Name: evaluating the effectiveness of cancer drug sensitization in vitro and in vivo
Uploaded: 2015-02-06T14:00:00.000+00:00
Duration: 9 min 19 s
Description: Watch this Scientific Journal Video about Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo at JoVE.com

This work was made possible by grants to JK from the Ontario Centres of Excellence and the Ontario Research Fund.
We would like to thank Siddika Pardhan and Dr. Peter Ferguson for technical assistance during filming.

NOTE: The following protocol was designed for use with adherent cells. Modifications are required to apply the method to non-adherent cells grown in suspension. The CAM experiments described in the protocol are designed for use with cells that express a fluorescent marker (e.g., GFP, RFP, etc.). Nine day old chicken embryos are required on day 2 of the experimental protocol for the CAM experiments.
1. Preparation and Transfection of Tumor Cells with Antisense Oligonucleotides (ASOs)
<ol>
	<li>Aspirate medium from T75 flask(s) containing cells of interest, wash with 1XPBS, and add 2 ml of 0.25% trypsin/EDTA. Add 10 ml of complete growth medium to each flask and transfer the cells in solution to a 50 ml tube. Count the cells and adjust the volume so that the final concentration is 1.0x105 cells per ml.</li>
	<li>Label two groups of T25 flasks: one group will contain eight flasks, labeled 1-8, and will be used for the real-time metabolism measurementexperiment; and the second group will also contain 8 flasks and will be used for the chicken embryo CAMexperiment. Add 2 ml of cells in solution to each flask and place in the incubator (37 &#176;C, 5% CO2 O/N).</li>
	<li>The next morning (Day 0, Time 0), label three 5 ml tubes as follows: control (non-targeting ASO or siRNA), &#39;target of interest&#39; (i.e., targeting ASO or siRNA), and Lipofectamine 2000 (or a similar transfection reagent). Dilute the stock ASO solutions to the appropriate concentration with serum free medium in the appropriate tube.
	<ol>
		<li>Add the required amount of transfection reagent to the appropriate tube and incubate in serum-free medium for 5 min. Add the transfection reagent solution to the ASO tubes and incubate for 20 min.</li>
	</ol>
	</li>
	<li>Add 250 &#181;l of control ASO transfection reagent solution to each of flasks 1-4 in each group, and 250 &#181;l of &#39;target of interest&#39; ASO transfection reagent solution to each of flasks 5-8 in each group. Incubate for 4 hr (37 &#7506;C, 5% CO2).
	<ol>
		<li>During incubation, carry out the steps described in section 2.1. After the incubation, add 3 ml of complete medium to each flask in the CAM experiment group and return to the incubator O/N (37 &#7506;C, 5% CO2). Process the metabolismexperiment group according to the description in section 2.2. Process the CAM experiment set according to the description in section 4.</li>
	</ol>
	</li>
</ol>
2. Biosensor Chip Preparation and Cell Seeding
<ol>
	<li>In a sterile environment, carefully wash six biosensor chips with 400 &#181;l of PBS. Sterilize the chips with 400 &#181;l of 70% ethanol for 20 min. Wash three times with 400 &#181;l of PBS.
	<ol>
		<li>Place the chips inside sterile tissue culture dishes to prevent contamination. Place three chips in a dish labeled &#39;control&#39;, and three in a dish labeled &#39;target of interest&#39;.</li>
	</ol>
	</li>
	<li>Label two 50 ml tubes as &#39;control&#39; and &#39;target of interest&#39;. Wash cells with PBS and add an appropriate volume of 0.25% Trypsin/EDTA. Wait until the monolayer detaches and collect the cells from each flask. Deposit the solution into the appropriate tube.
	<ol>
		<li>Count the cells and adjust the volume so that the final concentration is 6.0x105 cells/ml. Centrifuge and resuspend the cells if the initial concentration is too low.</li>
	</ol>
	</li>
	<li>Add 250 &#181;l of the cell solution to each biosensor chip in the appropriate group (for a total of 1.25x105 cells per chip). Perform this task one group at a time to minimize the risk of confusing the chips. Place the sterile dishes containing the chips inside a humidity chamber to prevent evaporation, and place the humidity chamber in the incubator O/N (37 &#7506;C, 5% CO2).</li>
	<li>The next morning (Day 1), carefully aspirate the medium from each chip and replace it with 250 &#181;l of growth medium supplemented with 0.2% fetal bovine serum (FBS) and 1x penicillin and streptomycin (P/S). Incubate for 4 hr (37 &#7506;C, 5% CO2).</li>
</ol>
3. Metabolism Measurement System Preparation and Solution Preparation
<ol>
	<li>During the incubation, prepare the requisite drug solutions and the metabolism measurement system for the upcoming assay. 
	NOTE: The metabolism measurement system contains a total of six modules. Each module accommodates one chip per experiment.
	<ol>
		<li>Subdivide the assay into the following experimental groups: one chip from each of the &#39;control&#39; and &#39;target of interest&#39; groups to receive vehicle for the duration of the assay; two chips from each group to receive drug treatment for a defined period of time during the assay, followed by vehicle during the washout period.</li>
		<li>For drug sensitization studies, modify the length, timing, and concentration of drug treatment to suit the particular drug in question. 
		NOTE: For cisplatin, the following steps were determined empirically with A549 cells, and may vary depending on cell line. Perform all stages with the default flow rate of 4 &#181;l/min. 
		6 hr of growth medium + 0.2% FBS and 1x P/S 
		24 hr of 6 &#181;M cisplatin in medium + 0.2% FBS 1x P/S 
		24 hr of growth medium + 0.2% FBS and 1x P/S 
		18 hr of growth medium + 0.2% FBS and 1x P/S 
		4 hr of 0.1% Triton-X 
		NOTE: Deviations from these steps will require calculation to determine the required volume of medium and drug solutions based on the desired flow rate and duration of experiment. The following sections are based on the steps described above.</li>
	</ol>
	</li>
	<li>Label and fill fourteen 50 ml tubes with 50 ml of growth medium + 0.2% FBS and 1x P/S. Place six in one metabolism measurement system tube rack, six in another, and the remaining two in a third tube rack that also contains tubes with cisplatin. Seal the first two racks with an air permeable membrane to prevent evaporation.</li>
	<li>Prepare a solution of 6 &#181;M cisplatin (of the appropriate volume) in medium + 0.2% FBS with 1x P/S. Dispense the required volume of cisplatin solution into four labeled 50 ml tubes.
	<ol>
		<li>Place the tubes in the remaining four slots in the third metabolism measurement tube rack. Ensure that the tubes are placed in the appropriate slots that correspond to the desired biomodules. Seal the tubes with an air permeable membrane.</li>
	</ol>
	</li>
	<li>Prepare and label six 50 ml tubes and fill them with 20 ml each of 0.1% Triton-X solution in medium. The Triton-X solution will lyse any remaining cells and provide a &#39;zero&#39; value for each chip. Place the tubes in a fourth metabolism measurement unit tube rack and seal with an air permable membrane to prevent excessive evaporation.</li>
	<li>Load the chips into the biomodules and initiate the experiment.</li>
</ol>
4. CAM Experiment Drug Treatment and Injection
NOTE: The steps and procedure for preparing chicken embryos for a CAM experiment are described elsewhere19
<ol>
	<li>Begin processing the CAM experiment 48 hr post-transfection (Day 2). Sub-divide the &#39;control&#39; and &#39;target of interest&#39; groups into two flasks for vehicle, and two for cisplatin. Aspirate the medium from the flasks and replenish with either 3 ml of fresh medium, or 6 &#181;M cisplatin. Incubate for 6 hr (37 &#7506;C, 5% CO2).</li>
	<li>Aspirate the medium, then wash and trypsinize the cells; collect the trypsinized cells in solution into four appropriately labeled 15 ml tubes.
	<ol>
		<li>Centrifuge and wash the cells three times with PBS. Re-suspend the cell pellet in 5 ml of PBS and count the cells.</li>
		<li>Adjust the volume so that the final cell concentration is 1.0x106 cells/ml. Transfer the cell solution into labeled 5 ml tubes for injection, and place on ice. Invert the tubes gently prior to injection to ensure that the cells are well mixed.</li>
	</ol>
	</li>
	<li>Set aside a total of 24 chicken embryos (9 days old) for injection (6 per group). Perform the injection using a glass needle attached to a flexible tube connected to a 1 ml syringe. The individual performing the injection should be blinded to the treatment group.
	<ol>
		<li>Using a stereo microscope, inject 1.0x105 cells in a volume of 100 &#181;l into the venous circulation of the CAM. Use a slow, pulsating technique to inject the full volume of cells. Gently dab the injection site with a soft wipe to stem the flow of blood and absorb any spillage. Label each embryo container appropriately following each injection.</li>
	</ol>
	</li>
	<li>Confirm the presence and distribution of fluorescent cells in the vasculature of the CAM following injection by visualizing them using a fluorescent microscope. Take note of any embryos in which the number of tumor cells appears low, or the distribution is poor.</li>
	<li>Place the chicken embryos in a humidity chamber and store them in an incubator (37 &#176;C, 60% humidity). Wait 7-9 days before enumerating metastatic foci.</li>
</ol>
5. Metastatic Focus Enumeration
<ol>
	<li>During the 7-9 day incubation period, monitor the embryos and discard any dead ones. Ensure that the humidity chamber remains moist at all times during the incubation period.</li>
	<li>Using a fluorescent stereo microscope at 20X magnification, scan the entire upper surface of the embryo CAM in a regular, grid-like pattern.</li>
	<li>Count the number of metastatic foci in each field of view, then tally the number for a final total per embryo. Doing so for the six embryos in each group will provide an average number of metastatic foci per treatment.</li>
</ol>

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The authors have nothing to disclose.

Due to the inherent cost and risk associated with clinical trials, there is a need to develop better and more rigorous pre-clinical testing methodology to adequately evaluate novel anti-cancer treatment regimens. Current commonly-used techniques all exhibit weaknesses that may limit their capacity to discriminate between potentially promising therapeutic targets/agents, and those that may be less effective. We devised a protocol to evaluate new anti-cancer approaches that addresses many of the shortcomings of traditional methods. 
A particularly important feature of the described protocol is the ability to measure cellular responses in real time, and to track changes in metabolism and adherence minute by minute. This allows for the identification of peak drug effects, optimal dosing and a more detailed understanding of the interaction between the components of drug combination treatment. Simultaneously, it provides insight into discrete metabolic alterations in cancer cells, which is information that is not provided by cell counting, apoptosis, or dye-conversion assays. A limitation of this assay is the inability to accurately determine the type of cell death that is occurring during drug treatment. Changes in viability will be reflected by changes in adherence to the biosensor chip, but this does not provide information regarding the manner of cell death. It is also possible to use fluorescence microscopy and live cell imaging techniques to determine similar metabolic data, and this can be used in addition to the experiments described in this protocol20,21. 
Furthermore, use of the chicken embryo CAM model to study metastatic frequency following treatment is an effective way to determine whether a new target, drug, or drug combination decreases the frequency of cancer cells which extravasate and/or invade surrounding tissue. This is a particularly relevant question from a clinical standpoint, because metastatic disease causes a high proportion of mortality amongst cancer patients. A potential limiting factor is that actual drug treatment does not occur in the CAM. Instead it occurs ex vivo and the pre-treated cells are then injected into the CAM. Therefore, this assay does not provide information regarding drug uptake or distribution in vivo. In addition, the intravenous CAM injections are technically challenging and require significant practice/experience. 
We used this protocol to evaluate the ability of a BRCA2-targeting ASO to sensitize tumor cells to the DNA damaging drug cisplatin. The results of our experiments identified BRCA2 as a promising target for therapeutic attack, and also provided rationale for further pre-clinical development of the BRCA2 ASO as a candidate drug. We envision this protocol being used to identify novel targets for combination treatment, particularly in the burgeoning field of DNA repair inhibition. We feel this protocol will be best used in addition to the more common techniques in cancer biology, in an effort to more stringently evaluate new anti-cancer approaches.

Acquired resistance to targeted and/or cytotoxic cancer treatment is an important clinical problem that can lead to treatment failure, relapse, and increased patient mortality1. Given the high level of heterogeneity in most tumors, it is a mathematical certainty that a tumor of sufficiently high cell number will contain a subset of cells resistant to single or combined therapies targeting molecular pathways on which those cells depend for survival2,3. Such tumor cells can be positively selected for during treatment, leading to disease recurrence. Development of novel therapies that simultaneously target different cancer cell survival mechanisms, either before or after treatment-mediated selection, is thus clinically important.
A high level of genome instability and mutation in tumor genomes is a fundamental characteristic that distinguishes cancer cells from non-tumor host cells4. Consequently, a useful strategy to increase the effectiveness of DNA-damaging chemotherapy and to prevent the development of resistance is to actively inhibit DNA repair in tumor cells5. This is an active field of investigation and a variety of novel DNA repair targets are being explored in a pre-clinical setting. A number of small molecule or antisense-based inhibitors of these targets have been developed and are undergoing testing6-8. The objective is to identify the most promising pre-clinical candidates and evaluate their safety and efficacy in clinical trials.
The high cost of clinical trials and the risk of failure (for a variety of reasons including sub-optimal pre-clinical evaluation) are formidable obstacles to progress in development of new therapies9. The use of appropriate and rigorous pre-clinical models to adequately evaluate new therapeutic targets and candidate drugs may decrease the high failure rate of clinical trials10.
Some commonly-used pre-clinical methods to evaluate the effectiveness of novel anti-cancer regimens are: a) measurement of capacity to reduce tumor cell proliferation in vitro (cell proliferation assays), b) therapy-induced reduction in capacity of tumor cells to form tissue culture colonies (colony formation assays), c) therapy-induced reduction in tumor cell metabolic activity in vitro (redox-dye conversion) , d) therapy-induced induction of in vitro tumor cell death (apoptotic, necrotic, autophagic, associated with mitosis and others)11, and e) in vivo therapy-induced reduction of growth or ablation of human and mouse xenografts12-14. 
A major weakness of the listed in vitro methods is that none of them provide continuous real-time evaluation of the effect of candidate therapies. Rather, they provide information only at selected, widely-separated time points during the course of treatment. Such measurements have diminished capacity to accurately reflect the magnitude and timing of tumor cell responses. In vivo mouse xenograft models are also limited by high cost, length of time to complete, and risk of sub-optimal dosing and treatment timing (scheduling). In addition, there is evidence that rodent xenograft models are limited predictors of clinical efficacy in humans, compared to in vitro assessment of responses of primary human tumor cells and established human tumor cell lines to candidate therapeutic interventions15,16. 
We devised a novel combination protocol to evaluate new drug combinations pre-clinically, in a manner that addresses the weaknesses of the more common procedures listed above. In place of proliferation, colony formation, or redox-dye conversion assays, we utilized a metabolism measurement unit to analyze cell adhesion, respiration, and acidification in real time during the entire treatment period17. Simultaneously, we investigated the effects of treatment combination in vivo by using a chicken embryo chorioallantoic membrane (CAM) model of invasion and metastasis18,19. We used these methods to evaluate the ability of an antisense oligonucleotide (ASO) targeting BRCA2 to potentiate the effectiveness of the commonly used chemotherapeutic drug cisplatin.

<table><tbody><tr><td>A549 cells</td><td>ATCC</td><td>CCL-185</td><td>http://www.atcc.org/products/all/CCL-185.aspx</td></tr><tr><td>AeraSeal film</td><td>Carl Roth GmbH</td><td></td><td></td></tr><tr><td>AMEM</td><td>Wisent Bioproducts</td><td>210-011-QK</td><td></td></tr><tr><td>Antisense oligodeoxynucleotides</td><td>Avecia</td><td></td><td>BRCA2 target sequence: 5&#039; - UAAGGAACGUCAAGAGAUAC - 3&#039; (bases 7241-7259 )</td></tr><tr><td>Axio Zoom V16 Microscope</td><td>Carl Zeiss</td><td></td><td>http://www.zeiss.ca/microscopy/en_ca/products/stereo-zoom-microscopes/axio-zoom-v16.html</td></tr><tr><td>Bionas Biosensor Chips</td><td>Bionas GmbH and Micronas GmbH</td><td>BIS8001D</td><td></td></tr><tr><td>Bionas Discovery 2500 System&amp;nbsp;</td><td>Bionas GmbH</td><td></td><td>http://www.bionas-discovery.com/prodservices/instruments/system2500/</td></tr><tr><td>Cisplatin</td><td>Sigma Aldrich</td><td>479306</td><td></td></tr><tr><td>Fertilized chicken eggs</td><td>Sourced locally</td><td></td><td></td></tr><tr><td>Fetal bovine serum&amp;nbsp;</td><td>Gibco - Life Technologies</td><td></td><td></td></tr><tr><td>Lipofectamine 2000&amp;nbsp;</td><td>Invitrogen - Life Technologies&amp;nbsp;</td><td>12566014</td><td>http://www.lifetechnologies.com/ca/en/home/life-science/protein-expression-and-analysis/transfection-selection/lipofectamine-2000.html</td></tr><tr><td>PBS</td><td>Wisent Bioproducts</td><td>311-010-CL</td><td></td></tr><tr><td>Trypsin (0.25%)/EDTA</td><td>Wisent Bioproducts</td><td>325-043-CL</td><td></td></tr></tbody></table>

evaluating the effectiveness of cancer drug sensitization in vitro and in vivo

Due to the high level of heterogeneity and mutations inherent in human cancers, single agent therapies, or combination regimens which target the same pathway, are likely to fail. Emphasis must be placed upon the inhibition of pathways that are responsible for intrinsic and/or adaptive resistance to therapy. An active field of investigation is the development and testing of DNA repair inhibitors that promote the action of, and prevent resistance to, commonly used chemotherapy and radiotherapy. We used a novel protocol to evaluate the effectiveness of BRCA2 inhibition as a means to sensitize tumor cells to the DNA damaging drug cisplatin. Tumor cell metabolism (acidification and respiration) was monitored in real-time for a period of 72 hr to delineate treatment effectiveness on a minute by minute basis. In combination, we performed an assessment of metastatic frequency using a chicken embryo chorioallantoic membrane (CAM) model of extravasation and invasion. This protocol addresses some of the weaknesses of commonly used in vitro and in vivo methods to evaluate novel cancer therapy regimens. It can be used in addition to common methods such as cell proliferation assays, cell death assays, and in vivo murine xenograft studies, to more closely discriminate amongst candidate targets and agents, and select only the most promising candidates for further development.

Results and figures adapted with permission from published work22.
BRCA2 inhibition induces a decrease in respiration in cisplatin treated tumor cells
Human A549 lung cancer cells treated with BRCA2-targeting ASO and cisplatin exhibited an early and irreversible decrease in respiration, compared to cells which received control ASO and cisplatin alone; after 24 hr of cisplatin treatment the difference in respiration between BRCA2 ASO and control ASO treated cells was 39% (Figure 1A). Importantly, this decrease in respiration started before a detectable drop in cell adhesion, suggesting that this occurred independent of changes in cell number. Respiration began to decrease approximately 10 hr before the first observable drop in adhesion, suggesting that a drop in respiration may be a formative event that precedes cell death (Figure 1B). No difference in acidification was observed during the 72 hr experiment time-frame, suggesting that BRCA2 ASO and cisplatin treatment has little to no effect on glucose metabolism (Figure 1C).
BRCA2 inhibition combined with cisplatin treatment decreases the frequency of metastasis
Human A549 lung cancer cells were treated with control ASO or BRCA2 ASO in the presence or absence of cisplatin, and injected into the venous circulation of the CAM (Figure 2A). Nine days following injection, cells treated with BRCA2 ASO and cisplatin exhibited a 77% lower frequency of metastatic foci compared to cells treated with control ASO and cisplatin, or BRCA2 ASO alone (Figure 2B). This suggests that BRCA2 ASO and cisplatin treatment has the potential to decrease or prevent metastatic burden in patients with solid tumors.
<img alt="Figure 1" src="/files/ftp_upload/52388/52388fig1highres.jpg" /> 
Figure 1.&#160;Real-time monitoring of tumor cell adherence, respiration, and acidification. A549 cells were transfected with BRCA2 ASO, plated onto biosensor chips, and treated with cisplatin for 24hrs using the Bionas Discovery System. Measurements of (A) respiration, (B) adherence, and (C) acidification were performed every 4 min over a period of 72 hr. Pink = control ASO, blue = BRCA2 ASO, green = control ASO + cisplatin, red = BRCA2 ASO + cisplatin. Figure adapted from published work with permission22. <a href="https://www.jove.com/files/ftp_upload/52388/52388fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/52388/52388fig2highres.jpg" /> 
Figure 2.&#160;Enumerating metastatic frequency using a chicken embryo CAM model. A549 cells transfected with BRCA2 ASO were treated with cisplatin for 6 hr, and then injected into the venous circulation of a 9 day old chicken embryo (A). Metastatic foci (B) (visualized using a confocal microscope with a 40x objective) were counted nine days following injection (C). Figure adapted from published work with permission22. <a href="https://www.jove.com/files/ftp_upload/52388/52388fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo at JoVE.com

Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo

Here, real-time monitoring of tumor cell metabolism, combined with an in vivo chicken embryo chorio-allantoic membrane (CAM) model of metastasis, are used to evaluate novel anti-cancer targets/agents for their ability to sensitize tumor cells to DNA damaging chemotherapeutics.

Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo

Due to the high level of heterogeneity and mutations inherent in human cancers, single agent therapies, or combination regimens which target the same ...

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Nanyang Technological University

Research

JoVE Journal

Medicine

8.2K Views.  Western University. Here, real-time monitoring of tumor cell metabolism, combined with an in vivo chicken embryo chorio-allantoic membrane (CAM) model of metastasis, are used to evaluate novel anti-cancer targets/agents for their ability to sensitize tumor cells to DNA damaging chemotherapeutics. 

Video: Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo

Establishing Dual Resistance to EGFR-TKI and MET-TKI in Lung Adenocarcinoma Cells In Vitro with a 2-step Dose-escalation Procedure

Drug resistance is a major challenge in cancer therapy. The generation of resistant sublines in vitro is necessary for discovering novel mechanisms to overcome this challenge. Here, a 2-step dose-escalation method for establishing dual-resistance to an epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), gefitinib, and a MET-TKI, PHA665752, is described. This method is based on simple stepwise dose-escalation of inhibitors for inducing acquired resistance in cell lines. The alternate method for generating resistant sublines involves exposing the cells to high concentrations of the inhibitor in one step. The stepwise dose-escalation method has a higher possibility of successfully inducing acquired resistance than this method. Activating EGFR mutations are biomarkers of a response to treatment with EGFR-TKI, which is an applied first-line treatment for non-small cell lung cancers (NSCLC) that harbor these mutations. However, despite reports of effective responses, the use of EGFR-TKI is limited because tumors inevitably acquire resistance. The major mechanisms behind EGFR-TKI resistance include a secondary mutation at the gatekeeper site, T790M in exon 20 of EGFR, and a bypass signal of MET. Thus, a potential solution for this issue would be a combination of EGFR-TKI and MET-TKI. This combined treatment has been shown to be effective in an in vitro study model. Acquired gefitinib-resistance was established through MET-amplification by stepwise dose-escalation of gefitinib for 12 months, and a cell line named PC-9MET1000 was generated in a previous study. To further investigate the mechanisms of acquired MET-TKI and EGFR-TKI resistance, a MET-TKI, PHA665752, was administered to these cells with stepwise dose-escalation in the presence of gefitinib for 12 months. This protocol has also been successfully applied for a number of combination therapies to establish acquired resistance to other inhibitor molecules.

Establishing Dual Resistance to EGFR-TKI and MET-TKI in Lung Adenocarcinoma Cells In Vitro with a 2-step Dose-escalation Procedure

An in vitro method for establishing dual resistance to an EGFR-TKI and a MET-TKI in cancer cells is described. This method is useful for developing treatments for patients with EGFR-mutations, who exhibit disease progression despite EGFR-TKI treatment with MET-amplification. It can also be modified for inhibitors targeting other molecules.

Drug resistance is a major challenge in cancer therapy. The generation of resistant sublines in vitro is necessary for discovering novel mechanisms to ...

Cancer Research

Preclinical Assessment of the Bioactivity of the Anticancer Coumarin OT48 by Spheroids, Colony Formation Assays, and Zebrafish Xenografts

In vitro and in vivo pre-clinical screening of novel therapeutic agents are an essential tool in cancer drug discovery. Although human cancer cell lines respond to therapeutic compounds in 2D (dimensional) monolayer cell cultures, 3D culture systems were developed to understand the efficacy of drugs in more physiologically relevant models. In recent years, a paradigm shift was observed in pre-clinical research to validate the potency of new molecules in 3D culture systems, more precisely mimicking the tumor microenvironment. These systems characterize the disease state in a more physiologically relevant manner and help to gain better mechanistic insight and understanding of the pharmacological potency of a given molecule. Moreover, with the current trend in improving in vivo cancer models, zebrafish has emerged as an important vertebrate model to assess in vivo tumor formation and study the effect of therapeutic agents. Here, we investigated the therapeutic efficacy of hydroxycoumarin OT48 alone or in combination with BH3 mimetics in lung cancer cell line A549 by using three different 3D culture systems including colony formation assays (CFA), spheroid formation assay (SFA) and in vivo zebrafish xenografts.

Here, we present the preclinical screening of anticancer coumarins using 3D culture and zebrafish.

In vitro and in vivo pre-clinical screening of novel therapeutic agents are an essential tool in cancer drug discovery. Although human cancer cell lines ...

Potentiation of Anticancer Antibody Efficacy by Antineoplastic Drugs: Detection of Antibody-drug Synergism Using the Combination Index Equation

Potentiation of hostile monoclonal antibodies (mAb) by chemotherapeutic agents constitutes a valuable strategy for designing effective and safer therapy against cancer. Here we provide a protocol to identify a rational combination at the preclinical step. First, we describe a cell-based assay to assess the synergism between anticancer mAb and cytotoxic drugs, that uses the combination index equation of Chou and Talalay1. This includes the measurement of tumor cell drug- and antibody-sensitivity using an MTT assay, followed by an automated computer analysis to calculate the combination index (CI) values. CI values of &lt;1 indicate synergism between tested mAbs and cytotoxic agents1. To corroborate the in vitro findings in vivo, we further describe a method to assess the combination regimen efficacy in a xenograft tumor model. In this model, the combined regimen significantly delays tumor growth, which results in a significant extended survival in comparison to single-agent controls. Importantly, the in vivo experimentation reveals that the combination regimen is well tolerated. This protocol allows the effective evaluation of anticancer drug combinations in preclinical models and the identification of rational combination to evaluate in clinical trials.

This protocol describes how to assess synergism between an anticancer antibody and antineoplastic drugs in preclinical models by using the combination index equation of Chou and Talalay.

Potentiation of hostile monoclonal antibodies (mAb) by chemotherapeutic agents constitutes a valuable strategy for designing effective and safer therapy ...

In Vitro Tumor Cell Rechallenge For Predictive Evaluation of Chimeric Antigen Receptor T Cell Antitumor Function

The field of chimeric antigen receptor (CAR) T cell therapy is rapidly advancing with improvements in CAR design, gene-engineering approaches and manufacturing optimizations. One challenge for these development efforts, however, has been the establishment of in vitro assays that can robustly inform selection of the optimal CAR T cell products for in vivo therapeutic success. Standard in vitro tumor-lysis assays often fail to reflect the true antitumor potential of the CAR T cells due to the relatively short co-culture time and high T cell to tumor ratio. Here, we describe an in vitro co-culture method to evaluate CAR T cell recursive killing potential at high tumor cell loads. In this assay, long-term cytotoxic function and proliferative capacity of CAR T cells is examined in vitro over 7 days with additional tumor targets administered to the co-culture every other day. This assay can be coupled with profiling T cell activation, exhaustion and memory phenotypes. Using this assay, we have successfully distinguished the functional and phenotypic differences between CD4+ and CD8+ CAR T cells against glioblastoma (GBM) cells, reflecting their differential in vivo antitumor activity in orthotopic xenograft models. This method provides a facile approach to assess CAR T cell potency and to elucidate the functional variations across different CAR T cell products.

Here, we describe an in vitro co-culture method to recursively challenge tumor-targeted T cells, which allows for phenotypic and functional analysis of antitumor T cell activity.

The field of chimeric antigen receptor (CAR) T cell therapy is rapidly advancing with improvements in CAR design, gene-engineering approaches and ...

Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications

Sensitization of adenylyl cyclase (AC) signaling has been implicated in a variety of neuropsychiatric and neurologic disorders including substance abuse and Parkinson&#39;s disease. Acute activation of G&#945;i/o-linked receptors inhibits AC activity, whereas persistent activation of these receptors results in heterologous sensitization of AC and increased levels of intracellular cAMP. Previous studies have demonstrated that this enhancement of AC responsiveness is observed both in vitro and in vivo following the chronic activation of several types of G&#945;i/o-linked receptors including D2 dopamine and &#956; opioid receptors. Although heterologous sensitization of AC was first reported four decades ago, the mechanism(s) that underlie this phenomenon remain largely unknown. The lack of mechanistic data presumably reflects the complexity involved with this adaptive response, suggesting that nonbiased approaches could aid in identifying the molecular pathways involved in heterologous sensitization of AC. Previous studies have implicated kinase and Gb&#947; signaling as overlapping components that regulate the heterologous sensitization of AC. To identify unique and additional overlapping targets associated with sensitization of AC, the development and validation of a scalable cAMP sensitization assay is required for greater throughput. Previous approaches to study sensitization are generally cumbersome involving continuous cell culture maintenance as well as a complex methodology for measuring cAMP accumulation that involves multiple wash steps. Thus, the development of a robust cell-based assay that can be used for high throughput screening (HTS) in a 384&#160;well format would facilitate future studies. Using two D2 dopamine receptor cellular models (i.e.&#160;CHO-D2L and HEK-AC6/D2L), we have converted our 48-well sensitization assay (&#62;20 steps 4-5 days) to a five-step, single day assay in 384-well format. This new format is amenable to small molecule screening, and we demonstrate that this assay design can also be readily used for reverse transfection of siRNA in anticipation of targeted siRNA library screening.

Persistent activation of inhibitory G protein-coupled receptors results in sensitization of adenylyl cyclase signaling. To identify the essential molecular pathways, nonbiased approaches are necessary; however, this strategy requires the development of a scalable cell-based cAMP sensitization assay. Herein, we describe a sensitization assay for small molecule and siRNA screening.

Sensitization of adenylyl cyclase (AC) signaling has been implicated in a variety of neuropsychiatric and neurologic disorders including substance abuse ...

Bioengineering

Patient-Derived Tumor Explants As a "Live" Preclinical Platform for Predicting Drug Resistance in Patients

An understanding of drug resistance and the development of novel strategies to sensitize highly resistant cancers rely on the availability of suitable preclinical models that can accurately predict patient responses. One of the disadvantages of existing preclinical models is the inability to contextually preserve the human tumor microenvironment (TME) and accurately represent intratumoral heterogeneity, thus limiting the clinical translation of data. By contrast, by representing the culture of live fragments of human tumors, the patient-derived explant (PDE) platform allows drug responses to be examined in a three-dimensional (3D) context that mirrors the pathological and architectural features of the original tumors as closely as possible. Previous reports with PDEs have documented the ability of the platform to distinguish chemosensitive from chemoresistant tumors, and it has been shown that this segregation is predictive of patient responses to the same chemotherapies. Simultaneously, PDEs allow the opportunity to interrogate molecular, genetic, and histological features of tumors that predict drug responses, thereby identifying biomarkers for patient stratification as well as novel interventional approaches to sensitize resistant tumors. This paper reports PDE methodology in detail, from collection of patient samples through to endpoint analysis. It provides a detailed description of explant derivation and culture methods, highlighting bespoke conditions for particular tumors, where appropriate. For endpoint analysis, there is a focus on multiplexed immunofluorescence and multispectral imaging for the spatial profiling of key biomarkers within both tumoral and stromal regions. By combining these methods, it is possible to generate quantitative and qualitative drug response data that can be related to various clinicopathological parameters and thus potentially be used for biomarker identification.

This paper describes methods for the generation, drug treatment, and analysis of patient-derived explants for assessing tumor drug responses in a live, patient-relevant, preclinical model system.

An understanding of drug resistance and the development of novel strategies to sensitize highly resistant cancers rely on the availability of suitable ...

Profiling Sensitivity to Targeted Therapies in EGFR-Mutant NSCLC Patient-Derived Organoids

Novel 3D cancer organoid cultures derived from clinical patient specimens represent an important model system to evaluate intratumor heterogeneity and treatment response to targeted inhibitors in cancer. Pioneering work in gastrointestinal and pancreatic cancers has highlighted the promise of patient-derived organoids (PDOs) as a patient-proximate culture system, with an increasing number of models emerging. Similarly, work in other cancer types has focused on establishing organoid models and optimizing culture protocols. Notably, 3D cancer organoid models maintain the genetic complexity of original tumor specimens and thus translate tumor-derived sequencing data into treatment with genetically informed targeted therapies in an experimental setting. Further, PDOs might foster the evaluation of rational combination treatments to overcome resistance-associated adaptation of tumors in the future. The latter focuses on intense research efforts in non-small-cell lung cancer (NSCLC), as resistance development ultimately limits the treatment success of targeted inhibitors. An early assessment of therapeutically targetable mechanisms using NSCLC PDOs could help inform rational combination treatments. This manuscript describes a standardized protocol for the cell culture plate-based assessment of drug sensitivities to targeted inhibitors in NSCLC-derived 3D PDOs, with potential adaptability to combinational treatments and other treatment modalities.

This protocol describes a standardized evaluation of drug sensitivities to targeted signaling inhibitors in NSCLC patient-derived organoid models.

Novel 3D cancer organoid cultures derived from clinical patient specimens represent an important model system to evaluate intratumor heterogeneity and ...

A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds

In the present study, we combined an in vitro 3D lung tumor model with an in silico model to optimize predictions of drug response based on a specific mutational background. The model is generated on a decellularized porcine scaffold that reproduces tissue-specific characteristics regarding extracellular matrix composition and architecture including the basement membrane. We standardized a protocol that allows artificial tumor tissue generation within 14 days including three days of drug treatment. Our article provides several detailed descriptions of 3D read-out screening techniques like the determination of the proliferation index Ki67 staining&#39;s, apoptosis from supernatants by M30-ELISA and assessment of epithelial to mesenchymal transition (EMT), which are helpful tools for evaluating the effectiveness of therapeutic compounds. We could show compared to 2D culture a reduction of proliferation in our 3D tumor model that is related to the clinical situation. Despite of this lower proliferation, the model predicted EGFR-targeted drug responses correctly according to the biomarker status as shown by comparison of the lung carcinoma cell lines HCC827 (EGFR -mutated, KRAS wild-type) and A549 (EGFR wild-type, KRAS-mutated) treated with the tyrosine-kinase inhibitor (TKI) gefitinib. To investigate drug responses of more advanced tumor cells, we induced EMT by long-term treatment with TGF-beta-1 as assessed by vimentin/pan-cytokeratin immunofluorescence staining. A flow-bioreactor was employed to adjust culture to physiological conditions, which improved tissue generation. Furthermore, we show the integration of drug responses upon gefitinib treatment or TGF-beta-1 stimulation - apoptosis, proliferation index and EMT - into a Boolean in silico model. Additionally, we explain how drug responses of tumor cells with a specific mutational background and counterstrategies against resistance can be predicted. We are confident that our 3D in vitro approach especially with its in silico expansion provides an additional value for preclinical drug testing in more realistic conditions than in 2D cell culture.

A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds

We present a three-dimensional (3D) lung cancer model based on a biological collagen scaffold to study sensitivity towards non-small-cell-lung-cancer-(NSCLC)-targeted therapies. We demonstrate different read-out techniques to determine the proliferation index, apoptosis and epithelial-mesenchymal transition (EMT) status. Collected data are integrated into an in silico model for prediction of drug sensitivity.

In the present study, we combined an in vitro 3D lung tumor model with an in silico model to optimize predictions of drug response based on a specific ...

In Vitro and In Vivo Evaluation of Photocontrolled Biologically Active Compounds - Potential Drug Candidates for Cancer Photopharmacology

Photocontrolled, biologically active compounds are an emerging class of &#34;smart&#34; drug candidates. They provide additional safety in systemic chemotherapy due to their precise spatiotemporal activation by directing a benign, non-ionizable light to a specific location within the patient&#39;s body. This paper presents a set of methods to evaluate the in vitro potency and ex vivo efficiency of the photoactivation of photocontrolled, biologically active compounds as well as the in vivo efficacy at early stages of drug development. The methodology is applied to anticancer cytotoxic peptides, namely, the diarylethene-containing analogs of a known antibiotic, gramicidin S. The experiments are performed using 2D (adherent cells) and 3D (spheroids) cell cultures of a cancer cell line (Lewis lung carcinoma, LLC), live tissue surrogates (pork meat mince), and an allograft cancer model (subcutaneous LLC) in immunocompetent mice. The selection of the most effective compounds and estimation of realistic phototherapeutic windows are performed via automated fluorescence microscopy. The photoactivation efficiency at varying illumination regimens is determined at different depths in a model tissue, and the optimal light dosage is applied in the final therapeutic in vivo experiment.

In Vitro and In Vivo Evaluation of Photocontrolled Biologically Active Compounds - Potential Drug Candidates for Cancer Photopharmacology

This protocol presents a set of experiments adopted for the evaluation of photoswitchable anticancer peptides, that can be used in the preclinical screening of such compounds. This includes cytotoxicity assessment in 2D and 3D cell cultures, the evaluation of ex vivo (model tissue) photoisomerization efficiency, and in vivo efficacy.

Photocontrolled, biologically active compounds are an emerging class of &#34;smart&#34; drug candidates. They provide additional safety in systemic ...

Chemistry

An Organotypic High Throughput System for Characterization of Drug Sensitivity of Primary Multiple Myeloma Cells

In this work we describe a novel approach that combines ex vivo drug sensitivity assays and digital image analysis to estimate chemosensitivity and heterogeneity of patient-derived multiple myeloma (MM) cells. This approach consists in seeding primary MM cells freshly extracted from bone marrow aspirates into microfluidic chambers implemented in multi-well plates, each consisting of a reconstruction of the bone marrow microenvironment, including extracellular matrix (collagen or basement membrane matrix) and stroma (patient-derived mesenchymal stem cells) or human-derived endothelial cells (HUVECs). The chambers are drugged with different agents and concentrations, and are imaged sequentially for 96 hr through bright field microscopy, in a motorized microscope equipped with a digital camera. Digital image analysis software detects live and dead cells from presence or absence of membrane motion, and generates curves of change in viability as a function of drug concentration and exposure time. We use a computational model to determine the parameters of chemosensitivity of the tumor population to each drug, as well as the number of sub-populations present as a measure of tumor heterogeneity. These patient-tailored models can then be used to simulate therapeutic regimens and estimate clinical response.

We describe a high-throughput drug sensitivity assay for primary multiple myeloma cells. It consists of a reconstruction of the bone marrow microenvironment (including extracellular matrix and stroma) in multi-well plates, and a non-invasive method for longitudinal quantification of cell viability.

In this work we describe a novel approach that combines ex vivo drug sensitivity assays and digital image analysis to estimate chemosensitivity and ...

Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo

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Chapters in this video

Establishing Dual Resistance to EGFR-TKI and MET-TKI in Lung Adenocarcinoma Cells In Vitro with a 2-step Dose-escalation Procedure

Preclinical Assessment of the Bioactivity of the Anticancer Coumarin OT48 by Spheroids, Colony Formation Assays, and Zebrafish Xenografts

Potentiation of Anticancer Antibody Efficacy by Antineoplastic Drugs: Detection of Antibody-drug Synergism Using the Combination Index Equation

In Vitro Tumor Cell Rechallenge For Predictive Evaluation of Chimeric Antigen Receptor T Cell Antitumor Function

Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications

Patient-Derived Tumor Explants As a "Live" Preclinical Platform for Predicting Drug Resistance in Patients

Profiling Sensitivity to Targeted Therapies in EGFR-Mutant NSCLC Patient-Derived Organoids

A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds

In Vitro and In Vivo Evaluation of Photocontrolled Biologically Active Compounds - Potential Drug Candidates for Cancer Photopharmacology

An Organotypic High Throughput System for Characterization of Drug Sensitivity of Primary Multiple Myeloma Cells