Dietary Phytochemicals in Cancer Signalling Pathways: Role of miRNA Targeting

Cancer is a multi-factorial health condition involving uncontrolled cell divisions. The disease has its roots in genetic mutation. This disease affects men, women, and even children. Chemotherapy, photodynamic, photothermal, and hormonal therapies have been used to treat this deadliest disease, but a huge percentage of patients have chances of disease recurrence or resistance. Nowadays, dysregulation in miRNAs is considered one of the key factors for the development and progression of different types of cancers as they control the expression of genes responsible for cell proliferation, growth, differentiation, and apoptosis. Dietary phytochemicals with anticancer properties have been gaining focus for cancer treatment since they have been found more effective in targeting cancer via regulating miRNAs expression. These phytochemicals have no side effects and are readily available at a low cost. Several dietary phytochemicals with regulatory effects on the expression of miRNAs have been reported, including curcumin, diallyl disulfide, 3, 30-diindolylmethane, ellagic acid, genistein, indole-3-carbinol, quercetin, resveratrol, and sulforaphane. They exert their regulatory effects against different cancers either by upregulating or downregulating different cancer signalling pathways and inhibiting their progression. Curcumin down-regulates SHH pathways, epigallocatechin-3-gallate regulates the Notch pathway and inhibits TGFβ1/SMAD signalling, and resveratrol regulates the Wnt/β-catenin pathway and carnosic acid-induced apoptosis in colon cancer cell via JAK2/STAT3 signalling pathway. The miRNAs are used for the treatment of cancer as essential modulators in cellular pathways. Therefore, identifying the miRNAs and their targets and countering them with specific phytochemicals provide a safe and effective mechanism for the treatment of cancer.