Molecular and cellular paradigms of multidrug resistance in cancer

BACKGROUND: The acquisition of resistance to chemotherapy is a major hurdle in the successful application of cancer therapy. Several anticancer approaches, including chemotherapies, radiotherapy, surgery and targeted therapies are being employed for the treatment of cancer. However, cancer cells reprogram themselves in multiple ways to evade the effect of these therapies, and over a period of time, the drug becomes inactive due to the development of multi‐drug resistance (MDR). MDR is a complex phenomenon where malignant cells become insensitive to anticancer drugs and attain the ability to survive even after several exposures of anticancer drugs. In this review, we have discussed the molecular and cellular paradigms of multidrug resistance in cancer. RECENT FINDINGS: An Extensive research in cancer biology revealed that drug resistance in cancer is the result of perpetuated intracellular and extracellular mechanisms such as drug efflux, drug inactivation, drug target alteration, oncogenic mutations, altered DNA damage repair mechanism, inhibition of programmed cell death signaling, metabolic reprogramming, epithelial mesenchymal transition (EMT), inherent cell heterogeneity, epigenetic changes, redox imbalance, or any combination of these mechanisms. An inevitable cross‐link between inflammation and drug resistance has been discussed. This review provided insight molecular mechanism to understand the vulnerabilities of cancer cells to develop drug resistance. CONCLUSION: MDR is an outcome of interplays between multiple intricate pathways responsible for the inactivation of drug and development of resistance. MDR is a major obstacle in regimens of successful application of anti‐cancer therapy. An improved understanding of the molecular mechanism of multi drug resistance and cellular reprogramming can provide a promising opportunity to combat drug resistance in cancer and intensify anti‐cancer therapy for the upcoming future.