Name: potentiation of anticancer antibody efficacy by antineoplastic drugs: detection of antibody-drug synergism using the combination index equation
Uploaded: 2019-01-19T13:30:00
Description: Watch this Scientific Journal Video about Potentiation of Anticancer Antibody Efficacy by Antineoplastic Drugs: Detection of Antibody-drug Synergism Using the Combination Index Equation at JoVE.com

Grant support: Fondation de Projet de L&#39;Universit&#233; de Nantes, les Bagouz&#39; &#224; Manon, La Ligue contre le Cancer comit&#233; de Loire-Atlantique, comit&#233; du Morbihan, and comit&#233; de Vend&#233;e, une rose pour S.A.R.A.H, L&#39;Etoile de Martin and la Soci&#233;t&#233; Fran&#231;aise de Lutte contre les Cancers et les leuc&#233;mies de L&#39;Enfant et de L&#39;adolescent (SFCE).&#160;M.B. and J.F. are supported by La Ligue Contre Le Cancer. The authors thank the UTE-facility of the Structure F&#233;d&#233;rative de Recherche Fran&#231;ois Bonamy. The authors also thank Dr. S. Suzin (Inserm, Paris) for providing the IMR5 cells and Ms. H. Est&#233;phan for her technical assistance.

Animal housing and experimental procedure were approved by the French Government (agreements #C44-278 and #APAFIS 03479.01). Animal care and procedures were conducted under directive EU 2010/63/EU and French Law #2013-118 on the protection of animals used for scientific purposes.
1. Evaluation of the Drug Interaction Between mAb 8B6 and Topotecan In Vitro
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	<li>96-well sample preparation 
	CAUTION: Consult the institution&#39;s Health and Safety committee a...

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Otol Neurotol 2012: 33;291-6.</a> Otol Neurotol. 34 (4), 777-778 (2013).</li><li>Choi, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitization+of+lung+cancer+cells+by+altered+dimerization+of+HSP27.">Sensitization of lung cancer cells by altered dimerization of HSP27.</a> Oncotarget. 8 (62), 105372-105382 (2017).</li><li>Weiner, L. M., Surana, R., Wang, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monoclonal+antibodies:+versatile+platforms+for+cancer+immunotherapy.">Monoclonal antibodies: versatile platforms for cancer immunotherapy.</a> Nature Reviews Immunology. 10 (5), 317-327 (2010).</li><li>Mellor, J. D., Brown, M. P., Irving, H. R., Zalcberg, J. 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W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+proapoptotic+antiganglioside+GM2+monoclonal+antibody+and+evaluation+of+its+therapeutic+effect+on+melanoma+and+small+cell+lung+carcinoma+xenografts.">Characterization of a proapoptotic antiganglioside GM2 monoclonal antibody and evaluation of its therapeutic effect on melanoma and small cell lung carcinoma xenografts.</a> Cancer Research. 65 (14), 6425-6434 (2005).</li><li>Nakamura, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Apoptosis+induction+of+human+lung+cancer+cell+line+in+multicellular+heterospheroids+with+humanized+antiganglioside+GM2+monoclonal+antibody.">Apoptosis induction of human lung cancer cell line in multicellular heterospheroids with humanized antiganglioside GM2 monoclonal antibody.</a> Cancer Research. 59 (20), 5323-5330 (1999).</li><li>Cochonneau, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+cycle+arrest+and+apoptosis+induced+by+O-acetyl-GD2-specific+monoclonal+antibody+8B6+inhibits+tumor+growth+in+vitro+and+in+vivo.">Cell cycle arrest and apoptosis induced by O-acetyl-GD2-specific monoclonal antibody 8B6 inhibits tumor growth in vitro and in vivo.</a> Cancer Letters. 333 (2), 194-204 (2013).</li><li>Chou, T. 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To predict the effect of drug interactions, three methods can be used: the isobologram methodology17, the nonlinear mixture model18, and the combination index1. Combination index analysis is the most commonly used because its application is simplified by the availability of a user-friendly computer program. For this purpose, we first characterized the dose-effect response of each agent used alone or in combination, by performing an MTT assay<sup clas...

The conventional approach in the treatment of a large number of different types of cancer was based on monotherapy. Even if it is still used in many cases, this method met several obstacles leading to opting for combined therapies2. Particularly, cancer cells are more susceptible to develop resistance when treated with a single drug by inducing alternative survival mechanisms3, resulting in therapeutic failure in patients4. Moreover, in monotherapy, drugs are usually administrated at a high dose. This situation often results in the occurrence of strong dose-dependent side effects that can be intolerable and force physicians to stop the treatment2. For these reasons, the association of anticancer molecules is now preferred to monotherapy.
Ideal drug combinations would be those that act in synergy against tumor cells, without increased toxicity against normal cells. Synergism refers to the interaction of two or more drugs that produces a therapeutic effect greater than the sum of each individual drug acting separately. Such interactions may result in enhanced clinical therapeutic efficacy2. It limits treatment resistance, increases efficacy, and can also reduce toxicity2. In fact, the dosage of each drug can be reduced to lower their side effects by targeting different pathways. In addition, one of the molecules can also serve as a sensitizing agent against cancer cells. The effect of the second drug may be enhanced on sensitized cells and fewer dosages can be used5.
Combined therapy can include two or more chemotherapeutic drugs and/or biologics, such as monoclonal antibodies6. These mAbs specifically target cells expressing a cell surface antigen of interest and are able to kill tumor cells through immunological pathways including antibody-dependent cell-mediated cytotoxicity (ADCC), with the involvement of immune effector cells7, and complement-dependent cytotoxicity (CDC)6. They can also act via a non-immunological mechanism mediated by apoptosis8,9,10,11. In this case, the induction of the process of programmed cell death may sensitize cancer cells, weaken their function, and make the associated chemotherapeutic drug more effective at a lower dosage. As such, proapoptotic mAb are good candidates for designing combination regimens with antineoplastic drugs.
Different mathematical models have been described to assess drug synergism; one of them is based on the combination index method1. This method is based on the median-effect principle developed by Chou1. The median-effect equation correlates the drug dose and drug effect as follows.
<img alt="Equation 1" src="/files/ftp_upload/58291/58291eq1.jpg" />
Here, D is the drug dose; Dm is the median-effect dose; Fa is the fraction affected by the dose; m is an exponent that signifies the shape of the dose-effect plot1. The median-effect dose is used to calculate the dose Dx of a drug that inhibits or kills &#34;x&#34; percent of cells. The CI value is then calculated to assess the additive effect of the drug combination, as follows1.
<img alt="Equation 2" src="/files/ftp_upload/58291/58291eq2.jpg" style="font-size: 14px;" />
A CI value of 1 indicates an additive effect and a CI value of &#60;1 indicates a synergistic effect, while a CI value of &#62;1 indicates antagonism1. The application of this method is further facilitated by the availability of a computer program, CompuSyn, that determines synergism and antagonism at all doses or effect levels simulated automatically12.
Our group has developed the mAb 8B6 specific for O-acetyl-GD2 ganglioside (OAcGD2) neuroblastoma antigen13 and further demonstrated that this mAb is able to induce cell death with attributes of apoptosis11. To test whether mAb 8B6 can sensitize neuroblastoma cells to the antineoplastic agent topotecan, we adapted the above-mentioned method developed by Chou1. First, we determine the effective dose 50 (ED50) values of mAb 8B6 and topotecan. Next, the neuroblastoma cells with equipotent ratios of the two compounds based on ED50 values are exposed to determine the CI values using the above-mentioned simulation software. This method allows us to demonstrate synergism between mAb 8B6 and topotecan in vitro. Next, we describe a protocol to further assess the potency and the safety of this combination regimen in vivo. This protocol can be easily applied to select potent and safe anticancer mAb and chemotherapeutic agent combinations in preclinical studies. A schematic representation of this study is provided in Figure 1.

<table border="0" cellpadding="0" cellspacing="0" style="width:1389px;" width="1390">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Cell Proliferation kit (MTT)</td>
			<td style="width:161px;">Roche</td>
			<td style="width:132px;">11-465-007-001</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">CompuSyn software</td>
			<td style="width:161px;">ComboSyn</td>
			<td style="width:132px;"></td>
			<td style="width:852px;">Combosyn can be downloaded for free at http://www.combosyn.com</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Electric shaver</td>
			<td style="width:161px;">Bioseb</td>
			<td style="width:132px;">BIO-1556</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Fetal calf serum</td>
			<td style="width:161px;">Eurobio</td>
			<td style="width:132px;">CVFSVFF00-01</td>
			<td style="width:852px;">10% heat-inactivated fetal calf serum in RPMI 1640</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Firefox&#160;</td>
			<td style="width:161px;">Mozilla Corporation</td>
			<td style="width:132px;"></td>
			<td style="width:852px;">Firefox can be downloaded for free at http://www.mozilla.org/en-US/firefox/</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Heat lamp</td>
			<td style="width:161px;">Verre&#38;Quartz</td>
			<td style="width:132px;">4003/1R</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:244px;">Human neuroblastoma IMR-5 cell line</td>
			<td style="width:161px;">Accegen Biotechnology</td>
			<td style="width:132px;">ABC-TC0450</td>
			<td style="width:852px;">IMR-5 is a clone of the human neuroblastoma cell line IMR32 5459762. IMR-5 cells were generously provided by Dr. Santos Susin (U.872, Paris, France)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">L-glutamine</td>
			<td style="width:161px;">Gibco</td>
			<td style="width:132px;">25030-024</td>
			<td style="width:852px;">2 mM in RPMI 1640</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Lysis solution&#160;</td>
			<td style="width:161px;">Roche&#160;</td>
			<td style="width:132px;">11-465-007-001</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">mAb 8B6</td>
			<td style="width:161px;">University of Nantes</td>
			<td style="width:132px;">N/A</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Matrigel</td>
			<td style="width:161px;">Corning</td>
			<td style="width:132px;">354248</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:244px;">Multiskan FC</td>
			<td style="width:161px;">Thermofischer Scientific&#160;</td>
			<td style="width:132px;">N08625</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Needle 21G 1 &#189;&#160;</td>
			<td style="width:161px;">BD Microlance</td>
			<td style="width:132px;">304432</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Needle 25G 1</td>
			<td style="width:161px;">Terumo</td>
			<td style="width:132px;">NN-2525R</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:244px;">NSG mice</td>
			<td style="width:161px;">Charles River Laboratories</td>
			<td style="width:132px;">5557</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:244px;">Nunc MicroWell 96-well microplates</td>
			<td style="width:161px;">Thermofisher</td>
			<td style="width:132px;">167008</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">PBS</td>
			<td style="width:161px;">VWR</td>
			<td style="width:132px;">L182-10</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">PBS, 0,05% EDTA</td>
			<td style="width:161px;">Sigma-Aldrich</td>
			<td>E9884</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">PC that runs windows 7</td>
			<td style="width:161px;">Microsoft</td>
			<td style="width:132px;"></td>
			<td style="width:852px;">Windows 7 can be purchased at http://www.microsoft.com/en-gb/software-download/windows7</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Penicillin-Streptomycin</td>
			<td style="width:161px;">Gibco</td>
			<td style="width:132px;">15140-122</td>
			<td style="width:852px;">100 units/mL penicillin and 100 mg/mL streptomycin in RPMI 1640</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:244px;">Reagent reservoir</td>
			<td style="width:161px;">Thermofischer Scientific</td>
			<td style="width:132px;">8094</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Rodent restrainer</td>
			<td style="width:161px;">Bioseb</td>
			<td style="width:132px;">TV-150-SM</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">RPMI 1640</td>
			<td style="width:161px;">Gibco</td>
			<td style="width:132px;">31870-025</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Syringe 1 mL</td>
			<td style="width:161px;">Henke Sass Wolf</td>
			<td style="width:132px;">5010.200V0</td>
			<td style="width:852px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Topotecan</td>
			<td style="width:161px;">Sigma-Aldrich</td>
			<td style="width:132px;">T2705</td>
			<td style="width:852px;"></td>
		</tr>
	</tbody>
</table>

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.

The representative results and figures are adapted with permission from earlier published work14.
Anti-OAcGD2 mAb 8B6 Synergistically Enhances the Inhibitory Effects of Topotecan on Neuroblastoma Cell Line Growth:
To establish the drug and the antibody concentrations to be used for assessing synergism between topotecan and mAb 8...

Watch this Scientific Journal Video about Potentiation of Anticancer Antibody Efficacy by Antineoplastic Drugs: Detection of Antibody-drug Synergism Using the Combination Index Equation at JoVE.com

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

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 ...

Research

JoVE Journal

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