g RNA Researchjournal homepage: keaipublishing/en/journals/non-coding-rna-researchmicroRNAs in cancer chemoresistance: The sword plus the shieldPriya Mondal a, b, Syed Musthapa Meeran a, b, a bDepartment of Biochemistry, CSIR-Central Meals Technological Analysis Institute, Mysore, 570020, India Academy of Scientific and Revolutionary Investigation (AcSIR), Ghaziabad, 201002, IndiaA R T I C L E I N F OKeywords: Cancer Noncoding RNA Multi-drug resistance Autophagy miRNA HypoxiaA B S T R A C TCancer is really a multifactorial illness and among the leading causes of mortality worldwide. Cancer cells create various approaches to decrease drug sensitivity and sooner or later result in chemoresistance. Chemoresistance is initiated either by intrinsic aspects or due to the prolonged use of chemotherapeutics as acquired resistance. Additional, chemoresistance is also one of the big reasons behind tumor recurrence and metastasis. Consequently, overcoming chemoresistance is amongst the key challenges in cancer therapy. Various mechanisms are involved in chemoresistance. Amongst them, the key function of ABC transporters and tumor microenvironment happen to be well studied. Lately, microRNAs (miRNAs) regulation in tumor development, metastasis, and chemotherapy has got wider interest on account of its part in regulating genes involved in cancer progression and therapy. Noncoding RNAs, including miRNAs, have already been linked together with the regulation of tumor-suppressor and P/Q-type calcium channel Purity & Documentation tumor-promoter genes. Further, miRNA can also be utilised as a dependable TrkC list diagnostic and prognostic marker to predict the stage and varieties of cancer. Current evidences have revealed that miRNAs regulation also influences the function of drug transporters as well as the tumor microenvironment, which impacts chemosensitivity to cancer cells. Therefore, miRNAs can be a promising target to reverse back chemosensitivity in cancer cells. This assessment comprehensively discusses the mechanisms involved in cancer chemoresistance and its regulation by miRNAs.1. Introduction Cancer is among the key non-communicable diseases along with the leading lead to of death worldwide. Chemotherapy will be the most typically preferred therapeutic strategy for the reason that of its effectiveness and widespread availability. On the other hand, most of the chemotherapies trigger adverse side effects, and the long-time use induces chemoresistance. Chemoresistance is really a mechanism when the prolonged use of an anticancer agent or maybe a group of anticancer agents fails to show its anti-cancerous house towards cancer cells and makes it possible for cancer cells or tumors to develop and metastasize into other organs aggressively. Chemoresistance is mainly of two forms such as innate-chemoresistance and acquiredchemoresistance [1]. Majorly, three elements are involved in drug resistance: first, decreased intake on the drugs inside the cell or increased release of drugs outdoors in the cell. The second will be the degradation and deactivation of intracellular thiols, and the third would be the advanced intracellular DNA repair mechanism. Besides these, numerous variables such as, mutation, hypoxia, cancer stem cells, and epigenetic modifications, are involved in the regulation of chemoresistance [2,3]. Amongst them,noncoding RNAs (ncRNAs), one of the fundamental epigenetic modifications, play a important role in chemoresistance. ncRNAs are endogenous, single-stranded RNAs which can modulate the expression of receptors and genes involved in cancer chemoresistance. ncRNAs are also known as epigenetic modifiers, as they regulate gene expression by modifying loca