The authors gratefully acknowledge the equipment grant from the Natural Science and Engineering Research (NSERC) Council of Canada for HPLC, the operating grant from the Canadian Institute of Health Research (CIHR) and Canadian Breast Cancer Research (CBCR) Alliance to X.Y. Wu, and the University of Toronto Scholarship to R.X. Zhang and T. Zhang.

All animal experiments were approved by the Animal Care Committee of University Health Network at the Ontario Cancer Institute and conducted in accordance with the Canadian Council on Animal Care Guidelines.
1. Biological Sample Preparation
<ol>
	<li>Collect the whole blood, major organs, and breast tumor at predetermined time-points after intravenous (i.v.) administration of drug-containing formulations (e.g., DMPLN, liposomal DOX)
	<ol>
		<li>Inject a breast tumor-bearing mouse i.v. with a prepared drug-containing formulation.</li>
		<li>Anesthetize the mouse at designated time-points (e.g., 15 min) by giving inhalable 2% isoflurane in a sealed chamber.</li>
		<li>Lay the anesthetized mouse on its back and put its nose through a nosepiece that constantly supplies 2% isoflurane. 
		NOTE: To ensure the mouse undergoes deep anesthesia, gently pinch fore limbs of the mouse and look for any twitching movement.</li>
		<li>Thoroughly clean the chest and abdomen regions using 70% ethanol and then perform a terminal procedure of cardiac puncture on the deep anesthetized mice using a heparinized 1 mL syringe and a 23 G needle.</li>
		<li>Collect the whole blood into a labeled sodium heparin sprayed plastic tube and gently swirl the tube to ensure collected whole blood comes into contact with the coated heparin of the tube wall. Collect a minimum of 50 &#181;L of whole blood. Always keep the samples on ice.</li>
		<li>Tape all four limbs of the mouse to secure it and open the abdominal cavity and ribcage of the mouse using a pair of scissors and forceps. Shift the intestines to the side and push the liver upward to sufficiently expose the portal vein. Cut the portal vein for the blood drainage.</li>
		<li>Perfuse the whole mouse body with 50 mL of ice-cold 0.9% saline through the heart using a 10 mL syringe with a 25 G needle. 
		NOTE: Bend the needle at 90&#176; for guiding the syringe into the portal vein.</li>
		<li>Excise organs in the following order: heart, lung, liver, spleen, kidneys. Then, separate the breast tumor from the surrounding connective tissues using a pair of incision scissors at the right mammary fat pad of the mouse. Collect all organs individually into 1.5 mL polypropylene tubes and quickly freeze them in liquid nitrogen. 
		&#8203;NOTE: Separate the gallbladder from the liver.</li>
		<li>Store the whole blood at 4 &#176;C and excised tissues in the -80 &#176;C freezer until later HPLC analysis.</li>
	</ol>
	</li>
	<li>Extract DOX, MMC and DOXol from biological matrices.
	<ol>
		<li>Weigh all frozen dissected tissues quickly and transfer them into a 13 mL rounded-bottom conical tube. To avoid possible drug metabolism or degradation, keep the samples on ice.</li>
		<li>Add 1-5 mL of ice-cold cell lysis buffer into the tube. 
		NOTE: The volume of buffer to use depends on the tissue weight based on the tissue-buffer ratio of 1 g: 5 mL (w/v); for small organs, such as heart and spleen, the ratio is 1 g: 2 mL.</li>
		<li>Use an up-down stroke motion to homogenize the tissue samples on ice at a speed of 18,000 rpm using an electric hand homogenizer. 
		NOTE: Completed homogenization requires approximately 3 to 5 iterations of a short homogenization process of less than 15 s, followed by tissue cooling over ice between each short homogenization.</li>
		<li>Wash the 10 mm saw-tooth generator probe of the homogenizer with distilled deionized (DDI) H2O, 70% ethanol, and then DDI H2O between each tissue sample to avoid cross-contamination.</li>
		<li>Transfer 50 &#181;L of tissue homogenate or whole blood into a 1.5 mL polypropylene micro-centrifuge tube and spike with 5 &#181;L of an internal standard (I.S.) 4-methylumbelliferone (4-MU) (2000 ng/mL) into the tube. 
		NOTE: 4-MU solution was prepared in methanol here.</li>
		<li>Add 250 &#181;L of an ice-cold extraction solvent into the tube containing whole blood or tissue homogenate. 
		NOTE: The extraction solvent consists of 60% acetonitrile (ACN) and 40% ammonium acetate (5 mM) with pH adjusted to pH = 3.5 using 0.05% formic acid. Use a 1:5 (v/v) sample: extraction solvent to volume ratio.</li>
		<li>Vigorously vortex the mixture for 2 min, centrifuge at 3,000 x g force at 4 oC for 10 min and pipet 200 &#181;L supernatant into another pre-chilled fresh micro-centrifuge tube.</li>
		<li>Evaporate supernatant at 60 &#176;C under a slow stream of nitrogen gas with protection from light.</li>
		<li>Reconstitute the dried residue with 100 &#181;L of ice-cold methanol, vigorously vortex for 30 s and centrifuge at 3000 x g at 4 &#176;C for another 5 min.</li>
		<li>Transfer the supernatant into a HPLC vial insert and place sample vials into an autosampler tray for injection.</li>
	</ol>
	</li>
</ol>
2. HPLC Instrumentation and Operation Parameters
<ol>
	<li>Prepare HPLC mobile-phase with consistent reproducibility
	<ol>
		<li>Measure 500 mL of HPLC-grade H2O using a graduated cylinder.</li>
		<li>Measure 500 mL of HPLC-grade acetonitrile (ACN) using a separate graduated cylinder.</li>
		<li>Carefully add 0.5 mL of trifluoroacetic acid (TFA) (CAUTION) into each of 500 mL of H2O and ACN to obtain the mobile phase of H2O and ACN containing 0.1% TFA, respectively. 
		NOTE: TFA is corrosive and toxic and should be handled under a laboratory fume hood. All solvent mixtures are prepared at room temperature.</li>
		<li>Filter mobile phases through a nylon membrane filter with a 0.45 &#181;m pore size and transfer it into clean HPLC reservoir bottles.</li>
	</ol>
	</li>
	<li>Set-up HPLC instrumentation for simultaneous detection of DOX, MMC, and DOXol and I.S. 4-MU.
	<ol>
		<li>Switch on the gradient pump, de-gasser, auto-sampler, photodiode array detector, and multi &#955; fluorescence detector.</li>
		<li>Input the initial conditions of mobile-phase composition to 16.5% H2O (0.1% TFA) and 83.5% ACN (0.1% TFA) (v/v).</li>
		<li>Set the UV detector on two channels, one at 310 nm for 4-MU (I.S.) and the other at 360 nm for MMC.</li>
		<li>Set the fluorescence detector on two channels, one at &#955;ex/&#955;em =365/445 nm for 4-MU and the other at &#955;ex/ &#955;em=480 nm/560 nm for DOX and DOXol, respectively.</li>
		<li>Set an isocratic flow rate of 1.0 mL/min.</li>
		<li>Equilibrate a preinstalled reverse phase C18 column (4.6 mm x 250 mm, 5 &#181;m) at room temperature for 10 min for baseline establishment.</li>
	</ol>
	</li>
	<li>Separate drugs (DOX, MMC, DOXol and 4-MU) using gradient mobile-phase condition.
	<ol>
		<li>Inject 15 &#181;L of extracted and re-concentrated samples using the auto-sampler.</li>
		<li>Gradually change the initial mobile-phase condition (refer to protocol step 2.2.2) to 100% ACN (0.1% TFA) over 18 min using the automated gradient pump. 
		NOTE: During the separation process, four channels (two UV absorbent and two fluorescent) appear simultaneously with each channel displaying one drug compound (refer to Protocol step 2.2.3 and 2.2.4).</li>
		<li>Maintain 100% of ACN (0.1% TFA) for 1 min and then return to the initial mobile phase condition within 1 min.</li>
		<li>Re-condition the column with the initial mobile phase at flow rate of 1.5 mL/min for 4 min for the next sample injection.</li>
	</ol>
	</li>
</ol>
3. HPLC Validation
<ol>
	<li>Prepare working standards of DOX, MMC and DOXol, and 4-MU (I.S.).
	<ol>
		<li>Weigh separately 1 mg of DOX and MMC drug powder (CAUTION) and 4-MU on a fresh small weighing paper (3 x 3 inches2). 
		Note All anticancer drugs are considered a health hazard that can cause acute toxicity and germ cell mutagenicity on inhalation or ingestion. They should be handled carefully with gloves and masks.</li>
		<li>Transfer the weighed DOX, MMC and 4-MU into a new individual 1.5 mL polypropylene micro-centrifuge tube.</li>
		<li>Add 1 mL of methanol and vortex briefly to obtain 1 mg/mL concentration of DOX and MMC.</li>
		<li>Add 1 mL of methanol into a vial containing pre-weighed 1 mg of DOXol (CAUTION) and vortex briefly to obtain 1 mg/mL concentration of DOXol. 
		NOTE: DOXol is a cardio-toxic metabolite and should be handled carefully.</li>
		<li>Pipette 20 &#181;L of prepared stock solutions of DOX, MMC, DOXol and 4-MU into a new separate 1.5 mL polypropylene micro-centrifuge tube and add 980 &#181;L of methanol to obtain a working standard of 20 &#181;g/mL of each drug.</li>
		<li>Dilute 20 &#181;g/mL of DOX, MMC and DOXol using methanol to obtain the working standards of 50 ng - 20 &#181;g /mL for DOX, MMC, and DOXol and 2000 ng/mL for I.S. 4-MU.</li>
		<li>Seal the cap of the tube of working solutions with a narrow piece of paraffin film covering to prevent methanol evaporation, wrap the entire tube with aluminum foil to avoid exposure to direct light and store at -20 &#176;C.</li>
	</ol>
	</li>
	<li>Determine the linearity, precision, and accuracy of DOX, MMC and DOXol in biological matrices (i.e., whole blood and tumor homogenate).
	<ol>
		<li>Simultaneously spike 5 &#181;L of working standards of DOX and DOXol (50 ng/mL - 20 &#181;g/mL), MMC (1,000 ng/mL - 16 &#181;g/mL), and 4-MU (2 &#181;g/mL) into 50 &#181;L of blank whole blood or tissue homogenate in polypropylene micro-centrifuge tubes to obtain the standard concentration curve ranging from 5 - 2000 ng/mL for drug compounds and 200 ng/mL for 4-MU (I.S.).</li>
		<li>Perform the drug extraction assay described in Protocol 1.2.</li>
		<li>Use low, median and high concentrations of DOX and DOXol (50, 500, and 2,000 ng/mL) and MMC (100, 1000, 2,000 ng/mL) for intra- and inter-day precision and accuracy. 
		NOTE: Prepare fresh standard concentrations on the day of analysis.</li>
	</ol>
	</li>
	<li>Analysis of samples
	<ol>
		<li>Inject 15 &#181;L of the sample using the auto-sampler.</li>
		<li>Gradually change the mobile phase over 0 to 18 min, increasing the composition of ACN over the interval.</li>
		<li>After 18 min, hold the mobile phase condition for 1 min.</li>
		<li>Return to the initial condition over the next 2 min, then re-equilibrate for 4 min before the next injection.</li>
		<li>After each sample run, note that the peaks of drug compounds with their retention time are shown as follow: MMC, DOXol, 4-MU (I.S.) and DOX.</li>
		<li>Integrate the peak area under curve (AUC) of drug compounds using HPLC software.</li>
		<li>Calculate the AUC ratio between individual drug compound and I.S. (Equation 1) and use the standard curves prepared under the same extraction procedures to determine the drug concentrations of DOX, MMC and DOXol in DMPLN formulation. 
		<img alt="Equation 1" src="/files/ftp_upload/56159/56159eq1.jpg" /></li>
		<li>Calculate the drug recovery percentage (Equation 2) by comparing the drug concentrations reconstituted using methanol from the extracts of spiked biological samples to that of the standard (&#34;neat&#34;) drug solution in methanol. 
		<img alt="Equation 2" src="/files/ftp_upload/56159/56159eq2.jpg" /></li>
	</ol>
	</li>
</ol>

The authors have no competing financial interests and conflicts of interest.

Compared to other chromatographic methods that enable the detection of a single drug species at a time, the present HPLC protocol is able to simultaneously quantitate three drug compounds (DOX, MMC, and DOXol) in the same biological matrix without the need to change the mobile phase. This preparation and analysis method has been successfully applied to determine the pharmacokinetics and bio-distribution of two nanoparticle-based drug delivery systems (i.e., liposomal DOX and DMPLN)22. Sin...

Chemotherapy is a primary treatment modality for many cancers yet it is often associated with severe adverse effects and limited efficacy due to drug resistance and other factors1,2,3. To improve the outcome of chemotherapy, drug combination regimens have been applied in the clinic based on considerations such as non-overlapping toxicities, different mechanisms of drug action, and non-cross drug resistance4,5,6. In clinical trials, a better tumor response rate was often observed using simultaneously administered drug combinations compared to a regimen of sequential drug delivery7,8. However, due to sub-optimal bio-distribution of free drug forms, simultaneous injection of multiple drugs can cause prominent normal tissue toxicity that outweighs the therapeutic effect9,10,11. Nanocarrier-based drug delivery has been shown to alter the pharmacokinetics and bio-distribution of encapsulated drugs, enhancing tumor-targeted accumulation12,13,14. As reviewed in our recent articles, nanoparticles co-loaded with synergistic drug combinations have demonstrated the capability to mitigate the problems encountered by free drug combinations, due to their controlled temporal and spatial co-delivery of multiple drugs to tumor tissue, enabling synergistic drug effects against cancer cells4,15,16. As a result, superior therapeutic efficacy and low toxicity have been demonstrated in both pre-clinical and clinical studies4,17,18.
Our previous in vitro studies found that the combination of two anticancer drugs, doxorubicin (DOX) and mitomycin C (MMC), produced a synergistic effect against several breast cancer cells lines and, furthermore, co-loading DOX and MMC within polymer-lipid hybrid nanoparticles (DMPLN) overcame various multi-drug resistant associated efflux pumps (e.g., P-glycoprotein and breast cancer resistant protein)19,20,21. In vivo, DMPLN enabled spatial-temporal co-delivery of DOX and MMC to tumor sites and increased bioavailability of drugs within cancer cells, as indicated by moderation of the formation of the DOX metabolite doxorubicinol (DOXol)22. As a result, the DMPLN enhanced tumor cell apoptosis, tumor growth inhibition, and prolonged host survival compared to free DOX and MMC combination or a liposomal DOX formulation22,23,24,25.
Analyzing the actual amount of drugs co-delivered by a nanocarrier is critical for designing effective nanoparticle formulations. Many methods have been developed to analyze the plasma level of single DOX or MMC doses using high performance liquid chromatography (HPLC) alone or in combination with mass spectrometry (MS)26,27,28,29,30,31,32,33,34. However, these methods are often time-consuming and impractical for combination therapy as a large number of biological samples need to be prepared separately for analysis of multiple drugs (sometimes including drug metabolites). In addition to the strong plasma protein binding of DOX and MMC, red blood cells also have a great capacity to bind and concentrate many anticancer drugs35,36. Thus, plasma analysis for DOX or MMC may obfuscate actual blood drug concentrations. The present work (Figure 1) describes a simple and robust multiple drug analysis method using reverse phase HPLC to simultaneously extract and quantitate DOX, MMC and the DOX metabolite doxorubicinol (DOXol) from whole blood and various tissues (e.g., tumors). It has been successfully applied to determine the pharmacokinetics and bio-distribution of DOX and MMC as well as the formation of DOXol after drug delivery via free solutions or nanoparticle forms (i.e., DMPLN and liposomal DOX) in an orthotopically implanted murine breast-tumor mouse model after intravenous (i.v.) injection22.

<table style="border-collapse:collapse;width:635pt" width="846">
	<colgroup>
		<col style="width:188pt" width="250" />
		<col style="width:122pt" width="162" />
		<col style="width:89pt" width="119" />
		<col style="width:236pt" width="315" />
	</colgroup>
	<tbody>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Doxorubicin&#160;</td>
			<td class="xl20" style="width:122pt" width="162">Polymed Theraeutics</td>
			<td class="xl20" style="width:89pt" width="119">111023</td>
			<td class="xl20" style="width:236pt" width="315">Anticancer drug</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Mitomycin C</td>
			<td class="xl20" style="width:122pt" width="162">Polymed Theraeutics</td>
			<td class="xl20" style="width:89pt" width="119">060814</td>
			<td class="xl20" style="width:236pt" width="315">Anticancer drug</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">Doxorubicinol (DOXol)</td>
			<td class="xl20" style="width:122pt" width="162">Toronto Research Chemicals</td>
			<td class="xl20" style="width:89pt" width="119">D558020</td>
			<td class="xl21">Metabolite of DOX</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">4-Methylumbelliferone sodium salt&#160;</td>
			<td class="xl20" style="width:122pt" width="162">Sigma-Aldrich</td>
			<td class="xl20" style="width:89pt" width="119">M1508</td>
			<td class="xl21">Internal standard</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Myristic Acid</td>
			<td class="xl20" style="width:122pt" width="162">Sigma-Aldrich</td>
			<td class="xl20" style="width:89pt" width="119">544-63-8&#160;&#160;</td>
			<td class="xl21">Materials for poly-lipid hybrid nanoparticles</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Polyoxyethylene (100) Stearate</td>
			<td class="xl20" style="width:122pt" width="162">Spectrum</td>
			<td class="xl20" style="width:89pt" width="119">M1402</td>
			<td class="xl21">Materials for poly-lipid hybrid nanoparticles</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Polyoxyethylene (40) Stearate</td>
			<td class="xl20" style="width:122pt" width="162">Sigma-Aldrich</td>
			<td class="xl20" style="width:89pt" width="119">P3440</td>
			<td class="xl21">Materials for poly-lipid hybrid nanoparticles</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Pluronic F68 (PF68)</td>
			<td class="xl20" style="width:122pt" width="162">BASF Corp.</td>
			<td class="xl20" style="width:89pt" width="119">9003-11-6</td>
			<td class="xl21">Materials for poly-lipid hybrid nanoparticles</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">Ultrasonication (UP100H)</td>
			<td class="xl20" style="width:122pt" width="162">Hielscher, Ultrasound Technology</td>
			<td class="xl20" style="width:89pt" width="119">NA</td>
			<td class="xl21">Nanoparticle preparation</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Water Bath (ISOTEMP 3016HS)</td>
			<td class="xl20" style="width:122pt" width="162">Fisher Scientific</td>
			<td class="xl20" style="width:89pt" width="119">NA</td>
			<td class="xl21">Nanoparticle preparation</td>
		</tr>
		<tr height="105" style="height:78.75pt">
			<td class="xl20" height="105" style="width:188pt;height:78.75pt" width="250">Liposomal Doxorubicin&#160; (Caelyx)</td>
			<td class="xl20" style="width:122pt" width="162">Janssen</td>
			<td class="xl20" style="width:89pt" width="119">Purchased from the pharmacy Princess Margaret Hospital</td>
			<td class="xl21">Clinically-approved nanoparticle formulation&#160;</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">HPLC-graded Methanol</td>
			<td class="xl21">Caledon Chemicals</td>
			<td class="xl20" style="width:89pt" width="119">6701-7-40</td>
			<td class="xl21">HPLC mobile phase composition</td>
		</tr>
		<tr height="25" style="height:18.75pt">
			<td class="xl20" height="25" style="width:188pt;height:18.75pt" width="250">HPLC-graded H2O</td>
			<td class="xl21">Caledon Chemicals</td>
			<td class="xl20" style="width:89pt" width="119">8801-7-40</td>
			<td class="xl21">HPLC mobile phase composition</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">HPLC-graded Acetonitrile&#160;</td>
			<td class="xl20" style="width:122pt" width="162">Caledon Chemicals</td>
			<td class="xl20" style="width:89pt" width="119">1401-7-40</td>
			<td class="xl21">HPLC mobile phase composition</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Trifluoroacetic Acid</td>
			<td class="xl20" style="width:122pt" width="162">Sigma-Aldrich</td>
			<td class="xl20" style="width:89pt" width="119">302031</td>
			<td class="xl21">HPLC mobile phase composition</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">0.45 &#956;m Nylon Membrane Filter Paper</td>
			<td class="xl20" style="width:122pt" width="162">Whatman</td>
			<td class="xl20" style="width:89pt" width="119">WHA7404004</td>
			<td class="xl21">HPLC mobile phase preparation</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl29" height="42" style="height:31.5pt">1cc Plastic Syringes</td>
			<td class="xl20" style="width:122pt" width="162">Becton, Dickinson and Company</td>
			<td class="xl20" style="width:89pt" width="119">2606-309659</td>
			<td class="xl21">Treatment injection</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl29" height="42" style="height:31.5pt">5cc Plastic Syringes</td>
			<td class="xl20" style="width:122pt" width="162">Becton, Dickinson and Company</td>
			<td class="xl20" style="width:89pt" width="119">2608-309646</td>
			<td class="xl21">Tissue collections</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">30G 1/2 Needles</td>
			<td class="xl20" style="width:122pt" width="162">Becton, Dickinson and Company</td>
			<td class="xl20" style="width:89pt" width="119">305106</td>
			<td class="xl21">Treatment injection</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">25G 5/8 Needles</td>
			<td class="xl20" style="width:122pt" width="162">Becton, Dickinson and Company</td>
			<td class="xl20" style="width:89pt" width="119">305122</td>
			<td class="xl21">Tissue collections</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">Sterile 0.9% Saline</td>
			<td class="xl20" style="width:122pt" width="162">Univeristy of Toronto House Brand</td>
			<td class="xl20" style="width:89pt" width="119">1011</td>
			<td class="xl21">Tissue perfusion</td>
		</tr>
		<tr height="22" style="height:16.5pt">
			<td class="xl20" height="22" style="width:188pt;height:16.5pt" width="250">13 ml Rounded-bottom conical tube&#160;</td>
			<td class="xl20" style="width:122pt" width="162">SARSTEDT</td>
			<td class="xl20" style="width:89pt" width="119">62.515.006</td>
			<td class="xl21">Prolyprolene, tissue homogenization</td>
		</tr>
		<tr height="23" style="height:17.25pt">
			<td class="xl30" height="23" style="height:17.25pt">Alpha Minimum Essential Medium (MEM)&#160;</td>
			<td class="xl27">Gibco</td>
			<td class="xl28" style="width:89pt" width="119">12571063</td>
			<td class="xl21">Cell medium</td>
		</tr>
		<tr height="22" style="height:16.5pt">
			<td class="xl20" height="22" style="width:188pt;height:16.5pt" width="250">1 x Phosphate Buffer Saline</td>
			<td class="xl20" style="width:122pt" width="162">Gibco</td>
			<td class="xl20" style="width:89pt" width="119">10010023</td>
			<td class="xl21">Tissue homogenization</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Triton X-100</td>
			<td class="xl20" style="width:122pt" width="162">Sigma-Aldrich</td>
			<td class="xl20" style="width:89pt" width="119">X100-100 ML</td>
			<td class="xl21">Tissue homogenization</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Formic acid</td>
			<td class="xl20" style="width:122pt" width="162">Caledon Chemicals</td>
			<td class="xl20" style="width:89pt" width="119">1/5/3840</td>
			<td class="xl21">Adjust pH for extraction solvent</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">Sodium heparin sprayed plastic tubes</td>
			<td class="xl20" style="width:122pt" width="162">Becton, Dickinson and Company</td>
			<td class="xl20" style="width:89pt" width="119">367878</td>
			<td class="xl21">Blood collection</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Analytical Weigh Balance&#160;</td>
			<td class="xl20" style="width:122pt" width="162">Sartorius&#160;</td>
			<td class="xl21">CPA225D</td>
			<td class="xl21">NA</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">pH meters&#160;</td>
			<td class="xl20" style="width:122pt" width="162">Fisher Scientific</td>
			<td class="xl26">13-637-671</td>
			<td class="xl21">accumet BASIC</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Vortex Mixter</td>
			<td class="xl20" style="width:122pt" width="162">Fisher Scientific</td>
			<td class="xl20" style="width:89pt" width="119">02-215-365</td>
			<td class="xl21">Vortexing samples at desired speed</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">1.5 ml&#160; Microcentrifuge Tube</td>
			<td class="xl20" style="width:122pt" width="162">Fisherbrand</td>
			<td class="xl20" style="width:89pt" width="119">2043-05408129</td>
			<td class="xl21">Prolyprolene</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Model 1000 homogenizer</td>
			<td class="xl22">Fisher Scientific</td>
			<td class="xl20" style="width:89pt" width="119">08-451-672</td>
			<td class="xl21">Tissue homogenization</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Centrifuge 5702R</td>
			<td class="xl20" style="width:122pt" width="162">Eppendorf</td>
			<td class="xl20" style="width:89pt" width="119">5702R</td>
			<td class="xl21">Extraction preparation</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Heated Evaporator System</td>
			<td class="xl20" style="width:122pt" width="162">Glas-Col</td>
			<td class="xl20" style="width:89pt" width="119">NA</td>
			<td class="xl21">Sample reconstitution</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">HPLC Screw Thread Vials</td>
			<td class="xl20" style="width:122pt" width="162">DIKMA</td>
			<td class="xl20" style="width:89pt" width="119">5320</td>
			<td class="xl21">HPLC sample injection</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl20" height="42" style="width:188pt;height:31.5pt" width="250">HPLC Screw Caps with PTFE White Silicone Septa</td>
			<td class="xl20" style="width:122pt" width="162">DIKMA</td>
			<td class="xl20" style="width:89pt" width="119">5325</td>
			<td class="xl21">HPLC sample injection</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">HPLC Polypropylene Insert&#160;&#160;</td>
			<td class="xl20" style="width:122pt" width="162">Agilent Technologies</td>
			<td class="xl20" style="width:89pt" width="119">5182-0549</td>
			<td class="xl21">Maximum volume 250 &#956;l, HPLC sample injection</td>
		</tr>
		<tr height="25" style="height:18.75pt">
			<td class="xl20" height="25" style="width:188pt;height:18.75pt" width="250">Xbridge C18 Column</td>
			<td class="xl23">Waters Corporation</td>
			<td class="xl20" style="width:89pt" width="119">186003117</td>
			<td class="xl21">Drug analysis</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Gradient pump&#160;</td>
			<td class="xl23">Waters Corporation</td>
			<td class="xl20" style="width:89pt" width="119">W600</td>
			<td class="xl21">Drug analysis</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Auto-sampler</td>
			<td class="xl23">Waters Corporation</td>
			<td class="xl20" style="width:89pt" width="119">W2707</td>
			<td class="xl21">Drug analysis</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Photodiode array detector&#160;</td>
			<td class="xl23">Waters Corporation</td>
			<td class="xl20" style="width:89pt" width="119">W2998</td>
			<td class="xl21">Drug analysis</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Multi &#955; fluoresence detector&#160;</td>
			<td class="xl23">Waters Corporation</td>
			<td class="xl20" style="width:89pt" width="119">W2475</td>
			<td class="xl21">Drug analysis</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">EMPOWER 2</td>
			<td class="xl23">Waters Corporation</td>
			<td class="xl20" style="width:89pt" width="119">NA</td>
			<td class="xl21">Data analysis software</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Scientist</td>
			<td class="xl20" style="width:122pt" width="162">Micromath</td>
			<td class="xl20" style="width:89pt" width="119">NA</td>
			<td class="xl21">Pharmacokinetic analysis</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl20" height="21" style="width:188pt;height:15.75pt" width="250">Female Balb/c Mice</td>
			<td class="xl20" style="width:122pt" width="162">Jackson Laboratory</td>
			<td class="xl20" style="width:89pt" width="119">001026</td>
			<td class="xl21">In vivo</td>
		</tr>
		<tr height="63" style="height:47.25pt">
			<td class="xl20" height="63" style="width:188pt;height:47.25pt" width="250">EMT6/WT Breast Cancer Cells</td>
			<td class="xl20" style="width:122pt" width="162">Provided by Dr. Ian Tannock; Ontario Cancer Institute</td>
			<td class="xl20" style="width:89pt" width="119">NA</td>
			<td class="xl21">In vivo</td>
		</tr>
	</tbody>
</table>

sample extraction and simultaneous chromatographic quantitation of doxorubicin and mitomycin c following drug combination delivery in nanoparticles to tumor-bearing mice

Combination chemotherapy is frequently used in the clinic for cancer treatment; however, associated adverse effects to normal tissue may limit its therapeutic benefit. Nanoparticle-based drug combination has been shown to mitigate the problems encountered by free drug combination therapy. Our previous studies have shown that the combination of two anticancer drugs, doxorubicin (DOX) and mitomycin C (MMC), produced a synergistic effect against both murine and human breast cancer cells in vitro. DOX and MMC co-loaded polymer-lipid hybrid nanoparticles (DMPLN) bypassed various efflux transporter pumps that confer multidrug resistance and demonstrated enhanced efficacy in breast tumor models. Compared to conventional solution forms, such superior efficacy of DMPLN was attributed to the synchronized pharmacokinetics of DOX and MMC and increased intracellular drug bioavailability within tumor cells enabled by the nanocarrier PLN. 
To evaluate the pharmacokinetics and bio-distribution of co-administered DOX and MMC in both free solution and nanoparticle forms, a simple and efficient multi-drug analysis method using reverse-phase high performance liquid chromatography (HPLC) was developed. In contrast to previously reported methods that analyzed DOX or MMC individually in the plasma, this new HPLC method is able to simultaneously quantitate DOX, MMC and a major cardio-toxic DOX metabolite, doxorubicinol (DOXol), in various biological matrices (e.g., whole blood, breast tumor, and heart). A dual fluorescent and ultraviolet absorbent probe 4-methylumbelliferone (4-MU) was used as an internal standard (I.S.) for one-step detection of multiple drug analysis with different detection wavelengths. This method was successfully applied to determine the concentrations of DOX and MMC delivered by both nanoparticle and solution approaches in whole blood and various tissues in an orthotopic breast tumor murine model. The analytical method presented is a useful tool for pre-clinical analysis of nanoparticle-based delivery of drug combinations.

Two anticancer drugs, DOX and MMC, as well as the DOX metabolite, DOXol, were simultaneously detected without any biological interference under the same applied gradient HPLC condition using 4-MU as the I.S. for both the fluorescence and UV detectors. DOX, MMC, DOXol and 4-MU were well-separated from each other with retention times of 5.7 min for MMC, 10.4 min for DOXol, 10.9 min for 4-MU, and 11.1 min for DOX (Figure 2). Each drug in whole blood and various ...

Watch this Scientific Journal Video about Sample Extraction and Simultaneous Chromatographic Quantitation of Doxorubicin and Mitomycin C Following Drug Combination Delivery in Nanoparticles to Tumor-b

Sample Extraction and Simultaneous Chromatographic Quantitation of Doxorubicin and Mitomycin C Following Drug Combination Delivery in Nanoparticles to Tumor-bearing Mice

This protocol describes an efficient and convenient analytical process of sample extraction and simultaneous determination of multiple drugs, doxorubicin (DOX), mitomycin C (MMC) and a cardio-toxic DOX metabolite, doxorubicinol (DOXol), in the biological samples from a preclinical breast tumor model treated with nanoparticle formulations of synergistic drug combination.

Combination chemotherapy is frequently used in the clinic for cancer treatment; however, associated adverse effects to normal tissue may limit its ...

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Pharmacokinetics and Pharmacodynamics

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Unit 1

Pharmacokinetic Models

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10.8K Views.  University of Toronto. This protocol describes an efficient and convenient analytical process of sample extraction and simultaneous determination of multiple drugs, doxorubicin (DOX), mitomycin C (MMC) and a cardio-toxic DOX metabolite, doxorubicinol (DOXol), in the biological samples from a preclinical breast tumor model treated with nanoparticle formulations of synergistic drug combination.

Video: Sample Extraction and Simultaneous Chromatographic Quantitation of Doxorubicin and Mitomycin C Following Drug Combination Delivery in Nanoparticles to Tumor-bearing Mice

The Colon-26 Carcinoma Tumor-bearing Mouse as a Model for the Study of Cancer Cachexia

Cancer cachexia is the progressive loss of skeletal muscle mass and adipose tissue, negative nitrogen balance, anorexia, fatigue, inflammation, and activation of lipolysis and proteolysis systems. Cancer patients with cachexia benefit less from anti-neoplastic therapies and show increased mortality1. Several animal models have been established in order to investigate the molecular causes responsible for body and muscle wasting as a result of tumor growth. Here, we describe methodologies pertaining to a well-characterized model of cancer cachexia: mice bearing the C26 carcinoma2-4. Although this model is heavily used in cachexia research, different approaches make reproducibility a potential issue. The growth of the C26 tumor causes a marked and progressive loss of body and skeletal muscle mass, accompanied by reduced muscle cross-sectional area and muscle strength3-5. Adipose tissue is also lost. Wasting is coincident with elevated circulating levels of pro-inflammatory cytokines, particularly Interleukin-6 (IL-6)3, which is directly, although not entirely, responsible for C26 cachexia. It is well-accepted that a primary mechanism by which the C26 tumor induces muscle tissue depletion is the activation of skeletal muscle proteolytic systems. Thus, expression of muscle-specific ubiquitin ligases, such as atrogin-1/MAFbx and MuRF-1, represent an accepted method for the evaluation of the ongoing muscle catabolism2. Here, we present how to execute this model in a reproducible manner and how to excise several tissues and organs (the liver, spleen, and heart), as well as fat and skeletal muscles (the gastrocnemius, tibialis anterior, and quadriceps). We also provide useful protocols that describe how to perform muscle freezing, sectioning, and fiber size quantification.

Mice bearing the Colon-26 (C26) carcinoma represent a classical model of cancer cachexia. Progressive muscle wasting occurs in association with tumor growth, over-expression of muscle-specific ubiquitin ligases, and reductions in muscle cross-sectional area. Fat loss is also observed. Cachexia is studied in a time-dependent manner with increasing severity of wasting.

Cancer cachexia is the progressive loss of skeletal muscle mass and adipose tissue, negative nitrogen balance, anorexia, fatigue, inflammation, and ...

Transfer of Manipulated Tumor-associated Neutrophils into Tumor-Bearing Mice to Study their Angiogenic Potential In Vivo

The contribution of neutrophils to the regulation of tumorigenesis is getting increased attention. These cells are heterogeneous, and depending on the tumor milieu can possess pro- or anti-tumor capacity. One of the important cytokines regulating neutrophil functions in a tumor context are type I interferons. In the presence of interferons, neutrophils gain anti-tumor properties, including cytotoxicity or stimulation of the immune system. Conversely, the absence of an interferon signaling results in prominent pro-tumor activity, characterized with strong stimulation of tumor angiogenesis. Recently, we could demonstrate that pro-angiogenic properties of neutrophils depend on the activation of nicotinamide phosphoribosyltransferase (NAMPT) signaling pathway in these cells. Inhibition of this pathway in tumor-associated neutrophils leads to their potent anti-angiogenic phenotype. Here, we demonstrate our newly established model allowing in vivo evaluation of tumorigenic potential of manipulated tumor-associated neutrophils (TANs). Shortly, pro-angiogenic tumor-associated neutrophils can be isolated from tumor-bearing interferon-deficient mice and repolarized into anti-angiogenic phenotype by blocking of NAMPT signaling. The angiogenic activity of these cells can be subsequently evaluated using an aortic ring assay. Anti-angiogenic TANs can be transferred into tumor-bearing wild type recipients and tumor growth should be monitored for 14 days. At day 14 mice are sacrificed, tumors removed and cut with their vascularization assessed. Overall, our protocol provides a novel tool to in vivo evaluate angiogenic capacity of primary cells, such as tumor-associated neutrophils, without a need to use artificial neutrophil cell line models. vc

Here, we show therapeutic potential of anti-angiogenic tumor-associated neutrophils after their transfer into tumor-bearing mice. This protocol can be used to manipulate neutrophil activity ex vivo and to subsequently evaluate their functionality in vivo&#160;in developing tumors. It is an appropriate model for studying potential neutrophil-based immunotherapies.

The contribution of neutrophils to the regulation of tumorigenesis is getting increased attention. These cells are heterogeneous, and depending on the ...

In Vivo Imaging and Quantitation of the Host Angiogenic Response in Zebrafish Tumor Xenografts

Tumor angiogenesis is a key target of anti-cancer therapy and this method has been developed to provide a new model to study this process in vivo. A zebrafish xenograft is created by implanting mammalian tumor cells into the perivitelline space of two days-post-fertilization zebrafish embryos, followed by measuring the extent of the angiogenic response observed at an experimental endpoint up to two days post-implantation. The key advantage to this method is the ability to accurately quantitate the zebrafish host angiogenic response to the graft. This enables detailed examination of the molecular mechanisms as well as the host vs tumor contribution to the angiogenic response. The xenografted embryos can be subjected to a variety of treatments, such as incubation with potential anti-angiogenesis drugs, in order to investigate strategies to inhibit tumor angiogenesis. The angiogenic response can also be live-imaged in order to examine more dynamic cellular processes. The relatively undemanding experimental technique, cheap maintenance costs of zebrafish and short experimental timeline make this model especially useful for the development of strategies to manipulate tumor angiogenesis.

The aim of this method is to generate an in vivo model of tumor angiogenesis by xenografting mammalian tumor cells into a zebrafish embryo that has fluorescently-labelled blood vessels. By imaging the xenograft and associated vessels, a quantitative measurement of the angiogenic response can be obtained.

Tumor angiogenesis is a key target of anti-cancer therapy and this method has been developed to provide a new model to study this process in vivo. A ...

Evaluation of the In vivo Antitumor Activity of Polyanhydride IL-1&#945; Nanoparticles

Cytokine therapy is a promising immunotherapeutic strategy that can produce robust antitumor immune responses in cancer patients. The proinflammatory cytokine interleukin-1 alpha (IL-1&#945;) has been evaluated as an anticancer agent in several preclinical and clinical studies. However, dose-limiting toxicities, including flu-like symptoms and hypotension, have dampened the enthusiasm for this therapeutic strategy. Polyanhydride nanoparticle (NP)-based delivery of IL-1&#945; would represent an effective approach in this context since this may allow for a slow and controlled release of IL-1&#945; systemically while reducing toxic side effects. Here an analysis of the antitumor activity of IL-1&#945;-loaded polyanhydride NPs in a head and neck squamous cell carcinoma (HNSCC) syngeneic mouse model is described. Murine oropharyngeal epithelial cells stably expressing HPV16 E6/E7 together with hRAS and luciferase (mEERL) cells were injected subcutaneously into the right flank of C57BL/6J mice. Once tumors reached 3-4 mm in any direction, a 1.5% IL-1a - loaded 20:80 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane:1,6-bis(p-carboxyphenoxy)hexane (CPTEG: CPH) nanoparticle (IL-1&#945;-NP) formulation was administered to mice intraperitoneally. Tumor size and body weight were continuously measured until tumor size or weight loss reached euthanasia criteria. Blood samples were taken to evaluate antitumor immune responses by submandibular venipuncture, and inflammatory cytokines were measured through cytokine multiplex assays. Tumor and inguinal lymph nodes were resected and homogenized into a single-cell suspension to analyze various immune cells through multicolor flow cytometry. These standard methods will allow investigators to study the antitumor immune response and potential mechanism of immunostimulatory NPs and other immunotherapy agents for cancer treatment.

Evaluation of the In vivo Antitumor Activity of Polyanhydride IL-1&#945; Nanoparticles

A standard protocol is described to study the antitumor activity and associated toxicity of IL-1&#945; in a syngeneic mouse model of HNSCC.

Cytokine therapy is a promising immunotherapeutic strategy that can produce robust antitumor immune responses in cancer patients. The proinflammatory ...

Exploring Mitochondrial Energy Metabolism of Single 3D Microtissue Spheroids Using Extracellular Flux Analysis

Three-dimensional (3D) cellular aggregates, termed spheroids, have become the forefront of in vitro cell culture in recent years. In contrast to culturing cells as two-dimensional, single-cell monolayers (2D culture), spheroid cell culture promotes, regulates, and supports physiological cellular architecture and characteristics that exist in vivo, including the expression of extracellular matrix proteins, cell signaling, gene expression, protein production, differentiation, and proliferation. The importance of 3D culture has been recognized in many research fields, including oncology, diabetes, stem cell biology, and tissue engineering. Over the last decade, improved methods have been developed to produce spheroids and assess their metabolic function and fate.
Extracellular flux (XF) analyzers have been used to explore mitochondrial function in 3D microtissues such as spheroids using either an XF24 islet capture plate or an XFe96 spheroid microplate. However, distinct protocols and the optimization of probing mitochondrial energy metabolism in spheroids using XF technology have not been described in detail. This paper provides detailed protocols for probing mitochondrial energy metabolism in single 3D spheroids using spheroid microplates with the XFe96 XF analyzer. Using different cancer cell lines, XF technology is demonstrated to be capable of distinguishing between cellular respiration in 3D spheroids of not only different sizes but also different volumes, cell numbers,&#160;DNA content and type.
The optimal mitochondrial effector compound concentrations of oligomycin, BAM15, rotenone, and antimycin A are used to probe specific parameters of mitochondrial energy metabolism in 3D spheroids. This paper also discusses methods to normalize data obtained from spheroids and addresses many considerations that should be considered when exploring spheroid metabolism using XF technology. This protocol will help drive research in advanced in vitro spheroid models.

These protocols will help users probe mitochondrial energy metabolism in 3D cancer cell-line-derived spheroids using Seahorse extracellular flux analysis.

Three-dimensional (3D) cellular aggregates, termed spheroids, have become the forefront of in vitro cell culture in recent years. In contrast to culturing ...

Simultaneous Imaging and Flow-Cytometry-based Detection of Multiple Fluorescent Senescence Markers in Therapy-Induced Senescent Cancer Cells

Chemotherapeutic drugs can induce irreparable DNA damage in cancer cells, leading to apoptosis or premature senescence. Unlike apoptotic cell death, senescence is a fundamentally different machinery restraining&#160;propagation of cancer cells. Decades of scientific studies have revealed the complex pathological effects of senescent cancer cells in tumors and microenvironments that modulate cancer cells and stromal cells. New evidence suggests that senescence is a potent prognostic factor during cancer treatment, and therefore rapid and accurate detection of senescent cells in cancer samples is essential. This paper presents a method to visualize and detect therapy-induced senescence (TIS) in cancer cells. Diffuse large B-cell lymphoma (DLBCL) cell lines were treated with mafosfamide (MAF) or daunorubicin (DN) and examined for the senescence marker, senescence-associated &#946;-galactosidase (SA-&#946;-gal), the DNA synthesis marker 5-ethynyl-2&#8242;-deoxyuridine (EdU), and the DNA damage marker gamma-H2AX (&#947;H2AX). Flow cytometer imaging can help generate high-resolution single-cell images in a short period of time to simultaneously visualize and quantify the three markers in cancer cells.

Here we present a flow cytometry-based method for visualization and quantification of multiple senescence-associated markers in single cells.

Chemotherapeutic drugs can induce irreparable DNA damage in cancer cells, leading to apoptosis or premature senescence. Unlike apoptotic cell death, ...

Non-Destructive Evaluation of Regional Cell Density Within Tumor Aggregates Following Drug Treatment

Multicellular tumor spheroid (MCTSs) models have demonstrated increasing utility for in vitro study of cancer progression and drug discovery. These relatively simple avascular constructs mimic key aspects of in vivo tumors, such as 3D structure and pathophysiological gradients. MCTSs models can provide insights into cancer cell behavior during spheroid development and in response to drugs; however, their requisite size drastically limits the tools used for non-destructive assessment. Optical Coherence Tomography structural imaging and Imaris 3D analysis software are explored for rapid, non-destructive, and label-free measurement of regional cell density within MCTSs. This approach is utilized to assess MCTSs over a 4-day maturation period and throughout an extended 5-day treatment with Trastuzumab, a clinically relevant anti-HER2 drug. Briefly, AU565 HER2+ breast cancer MCTSs were created via liquid overlay with or without the addition of Matrigel (a basement membrane matrix) to explore aggregates of different morphologies (thicker, disk-like 2.5D aggregates or flat 2D aggregates, respectively). Cell density within the outer region, transitional region, and inner core was characterized in matured MCTSs, revealing a cell-density gradient with higher cell densities in core regions compared to outer layers. The matrix addition redistributed cell density and enhanced this gradient, decreasing outer zone density and increasing cell compaction in the cores. Cell density was quantified following drug treatment (0 h, 24 h, 5 days) within progressively deeper 100 &#181;m zones to assess potential regional differences in drug response. By the final timepoint, nearly all cell death appeared to be constrained to the outer 200 &#181;m of each aggregate, while cells deeper in the aggregate appeared largely unaffected, illustrating regional differences in the drug response, possibly due to limitations in drug penetration. The current protocol provides a unique technique to non-destructively quantify regional cell density within dense cellular tissues and measure it longitudinally.

The present protocol develops an image-based technique for rapid, non-destructive, and label-free regional cell density and viability measurement within 3D tumor aggregates. Findings revealed a cell-density gradient, with higher cell densities in core regions than outer layers in developing aggregates and predominantly peripheral cell death in HER2+ aggregates treated with Trastuzumab.

Multicellular tumor spheroid (MCTSs) models have demonstrated increasing utility for in vitro study of cancer progression and drug discovery. These ...

Quantifying Telomere Length Using Non-Radioactive Chemiluminescence Detection

Optimization of Performance Parameters of the TAGGG Telomere Length Assay

Telomeres are repetitive sequences which are present at chromosomal ends; their shortening is a characteristic feature of human somatic cells. Shortening occurs due to a problem with end replication and the absence of the telomerase enzyme, which is responsible for maintaining telomere length. Interestingly, telomeres also shorten in response to various internal physiological processes, like oxidative stress and inflammation, which may be impacted due to extracellular agents like pollutants, infectious agents, nutrients, or radiation. Thus, telomere length serves as an excellent biomarker of aging and various physiological health parameters. The TAGGG telomere length assay kit is used to quantify average telomere lengths using the telomere restriction fragment (TRF) assay and is highly reproducible. However, it is an expensive method, and because of this, it is not employed routinely for large sample numbers. Here, we describe a detailed protocol for an optimized and cost-effective measurement of telomere length using Southern blots or TRF analysis and non-radioactive chemiluminescence-based detection.

Author Spotlight: Optimization of Performance Parameters of the TAGGG Telomere Length Assay  

Here, we describe in detail the protocol for quantifying telomere length using non-radioactive chemiluminescent detection, with a focus on the optimization of various performance parameters of the TAGGG telomere length assay kit, such as buffer quantities and probe concentrations.

Telomeres are repetitive sequences which are present at chromosomal ends; their shortening is a characteristic feature of human somatic cells. Shortening ...

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Diagnosis of Vitreoretinal Lymphoma Using Cell-Free DNA

Cell-Free DNA Extraction of Vitreous and Aqueous Humor Specimens for Diagnosis and Monitoring of Vitreoretinal Lymphoma

Vitreoretinal lymphoma (VRL) represents an aggressive lymphoma, often categorized as primary central nervous system diffuse large B-cell lymphoma. To diagnose VRL, specimens such as vitreous humor and, more recently, aqueous humor are collected. Diagnostic testing for VRL on these specimens includes cytology, flow cytometry, and molecular testing. However, both cytopathology and flow cytometry, along with molecular testing using cellular DNA, necessitate intact whole cells. The challenge lies in the fact that vitreous and aqueous humor typically have low cellularity, and many cells get destroyed during collection, storage, and processing. Moreover, these specimens pose additional difficulties for molecular testing due to the high viscosity of vitreous humor and the low volume of both vitreous and aqueous humor. This study proposes a method for extracting cell-free DNA from vitreous and aqueous specimens. This approach complements the extraction of cellular DNA or allows the cellular component of these specimens to be utilized for other diagnostic methods, including cytology and flow cytometry.

Author Spotlight: Advancing VRL Diagnosis Using Cell-Free DNA Extraction from Vitreous Humor 

A procedure to extract cell-free DNA from vitreous and aqueous humor to perform molecular studies for diagnosing vitreoretinal lymphoma is established here. The method offers the ability to concurrently extract DNA from the cellular component of the sample or to reserve it for ancillary testing.

Vitreoretinal lymphoma (VRL) represents an aggressive lymphoma, often categorized as primary central nervous system diffuse large B-cell lymphoma. To ...

Common Carotid Artery Repair After Injection in a Mouse Model 

Facilitating Repeat Intracarotid Injections in Mouse Models by a Novel Injection Site Repair Technique

Given recent advances in the delivery of novel antitumor therapeutics using endovascular selective intraarterial delivery methods in neuro-oncology, there is an urgent need to develop methods for intracarotid injections in mouse models, including methods to repair the carotid artery in mice after injection to allow for subsequent injections. We developed a method of intracarotid injection in a mouse model to deliver therapeutics into the internal carotid artery (ICA) with two alternative procedures. 
During injection, the needle is inserted into the common carotid artery (CCA) after tying a suture around the external carotid artery (ECA) and injected therapeutics are delivered into the ICA. Following injection, the common carotid artery (CCA) can be ligated, which limits the number of intracarotid injections to one. The alternative procedure described in this article includes a modification where intracarotid artery injection is followed by injection site repair of the CCA, which restores blood flow within the CCA and avoids the complication of cerebral ischemia seen in some mouse models. 
We also compared the delivery of bone marrow-derived human mesenchymal stem cells (BM-hMSCs) to intracranial tumors when delivered through intracarotid injection with and without injection site repair following the injection. Delivery of BM-hMSCs does not differ significantly between the methods. Our results demonstrate that injection site repair of the CCA allows for repeat injections through the same artery and does not impair the delivery and distribution of injected material, thus providing a model with greater flexibility that more closely emulates intracarotid injection in humans.

Author Spotlight: Advancing Glioblastoma Treatment Through Intraarterial Delivery Strategies for Oncolytic Viruses and MicroRNAs

Repair of the intracarotid artery in a mouse model after injection returns blood flow to the artery without negatively impacting the distribution of the injected material. Injection site repair facilitates subsequent injections through the same artery and prevents cerebral ischemia in mouse strains that lack a complete Circle of Willis.

Given recent advances in the delivery of novel antitumor therapeutics using endovascular selective intraarterial delivery methods in neuro-oncology, there ...