Dear Anil

Dear Anil Kuman,

First I encourage you to read the attached article referred to: MCF-7/ADR cells (re-designated NCI/ADR-RES) are not derived from MCF-7 breast cancer cells: a loss for breast cancer multidrug-resistant research. It is well known that cells lines cultured in vitro may undergo genetic drift.

 Concerning your question, your natural drug may have an action on some signaling pathway (s).  One possibility is that this signaling pathway is crucial for your  MCF/ADR cells. There is away to know the difference on signaling pathways of your cells that could help you to decipher probably the target of your drug such as the inhibition of the phosphorylation of one protein.  

 Do the phospho kinase array this could help you.  You will find an attached file referred to the product.

 Make your experiment at the same time with the same rate of cell number of MCF7 and MCF7/ADR and the same time of incubation and the concentration of the drug. do not wait until cell death.  The kit is very expensive approximately 400 Euro; so first do test to evaluate the ideal time to stop your culture before reaching the apoptosis of all the cells.

May be other researchers could help you with other reference of phosphor kinase array kit  less expensive and with more proteins

Good luck

Is it possible that a compound that doesn't affect one cell type affects another cell type?  Yes, of course it is.  That's essentially the question you're asking.  Although both lines are MCF-7, acquisition of resistance requires significant changes in a potentially innumerable number of genes and pathways.  Both lines are called MCF-7, but for all intents and purposes, these two cell lines aren't the same cell lines any more.  However, an academic answer like that doesn't help you very much.  To answer your question, I'll ask you two questions in return: 1. What is the MOA for your test compound (or at least proposed MOA) and 2. What is known in the literature about acquisition of doxorubicin resistance and the genetic or pathway changes that occur?  I'm not an expert with dox resistance but let's hypothesize that cells that are able to become resistant to dox tend to have altered expression of DNA damage repair proteins like ATM, ATR, DNA-PKcs, BRCA1 or 2, or perhaps a decreased expression of caspases or perhaps a downregulation of cell cycle proteins like CDKs or p53.  Looking at any or all of these proteins could help you to understand what makes these two cell lines different and then when you use your test compound, how that test compound affects those proteins.  Similarly, looking at cell cycle, via FACS could help to show that your resistant cells are undergoing massive arrest or doing an Annexin V assay could show major cell death.  Or doing H2AX foci, or a comet assay could show higher cell death and indicate how the test compound works in these cells.  There are a lot of ways to interrogate this system, but getting at the right assays requires you to know how your test compound works and what doxorubicin resistance is likely doing to your cells.

Dear Dr. Anil 

Usually natural compounds have shown to induce broad toxicity towards tumor cells but we partly assumed it has selective toxicity based on expression studies (specific genes and protein expression).  But if you think aside, cancer cells utilizes two mechanism such as "flight and fight" by altering their receptor proteins. Coming to your question, resistant cells already tuned their membranous receptor and proteins to inhibit the binding of resistant drugs, so their focus particularly on to eliminate the drug showing resistance to cancer cells but not for unresistant compound. May be this might the reason i think so that your compound showed an effective signatures against resistance cells to that of parental cells.

With regards,

Mani

Dear Dr. Anil Kumar Chauhan,

Sometimes resistant cells are proliferating much faster than the parental ones. This could affect your cytotoxicity assay resulsting in lower IC50s for the fast proliferating cells, i.e. the resistant ones.

Best regards,

Harris Pratsinis

Thank you, everyone, for your valuable suggestions... :) 

Hi Anil,

Sometimes natural compounds have a specific effect on cells with cancer stem cell phenotype. I know that some drug-resistant cell lines have a higher proportion of cells with CSC phenotype. Is it possible that this is the case for MCF-7/ADR? It might be worth checking out. You can do a quick flow cytometry staining with anti-CD44 and anti-CD24: cells with CSC phenotype should be CD44+/CD24-. Good luck!