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 Research Institute, Mysore, 570020, India Academy of Scientific and Innovative Analysis (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 actually a multifactorial illness and among the top αvβ5 web causes of mortality worldwide. Cancer cells create various approaches to lessen drug sensitivity and ultimately result in chemoresistance. Chemoresistance is initiated either by intrinsic things or due to the prolonged use of chemotherapeutics as acquired resistance. Further, chemoresistance can also be one of the important factors behind tumor recurrence and metastasis. For that reason, overcoming chemoresistance is amongst the principal challenges in cancer therapy. Many mechanisms are involved in chemoresistance. Amongst them, the essential part of ABC transporters and tumor microenvironment have been properly studied. Recently, microRNAs (miRNAs) regulation in tumor development, metastasis, and chemotherapy has got wider interest Topoisomerase Synonyms because of its function in regulating genes involved in cancer progression and therapy. Noncoding RNAs, which includes miRNAs, have already been associated with the regulation of tumor-suppressor and tumor-promoter genes. Further, miRNA also can be employed as a reliable diagnostic and prognostic marker to predict the stage and kinds of cancer. Current evidences have revealed that miRNAs regulation also influences the function of drug transporters and the tumor microenvironment, which affects chemosensitivity to cancer cells. For that reason, miRNAs could be a promising target to reverse back chemosensitivity in cancer cells. This critique comprehensively discusses the mechanisms involved in cancer chemoresistance and its regulation by miRNAs.1. Introduction Cancer is amongst the important non-communicable ailments plus the major result in of death worldwide. Chemotherapy could be the most generally preferred therapeutic strategy due to the fact of its effectiveness and widespread availability. On the other hand, the majority of the chemotherapies bring about adverse unwanted effects, and also the long-time use induces chemoresistance. Chemoresistance is often a mechanism when the prolonged use of an anticancer agent or even a group of anticancer agents fails to show its anti-cancerous property towards cancer cells and allows cancer cells or tumors to develop and metastasize into other organs aggressively. Chemoresistance is mainly of two types which include innate-chemoresistance and acquiredchemoresistance [1]. Majorly, three elements are involved in drug resistance: initially, decreased intake of your drugs inside the cell or improved release of drugs outside of your cell. The second may be the degradation and deactivation of intracellular thiols, along with the third is definitely the sophisticated intracellular DNA repair mechanism. Apart from these, many components including, mutation, hypoxia, cancer stem cells, and epigenetic alterations, are involved inside the regulation of chemoresistance [2,3]. Amongst them,noncoding RNAs (ncRNAs), one of the basic epigenetic modifications, play a vital part in chemoresistance. ncRNAs are endogenous, single-stranded RNAs that will modulate the expression of receptors and genes involved in cancer chemoresistance. ncRNAs are also referred to as epigenetic modifiers, as they regulate gene expression by modifying loca