Role of dietary phytochemicals in modulation of miRNA expression: Natural swords combating breast cancer

The National Cancer Institute had projected breast cancer (BC) as one of the topmost prevalent malignancies around the globe. In many cases, BC becomes resistant to chemotherapy, radiation and hormonal therapies. Traditional BC therapies are associated with adverse side effects, drug resistance and recurrence. Extensive research work has shown that these dietary phytochemicals (DPs) may exert therapeutic effects by regulating the miRNA expression. A large number of DPs have been researched as miRNA regulatory agents against BC and some other DPs have not yet been tested against BC. We have discussed the effects of curcumin, diallyl disulphide, 3,3' diindolylmethane, ellagic acid, genistein, indole-3-carbinol, quercetin, resveratrol, and sulforaphane on regulation of expression of BC miRNAs in a wide range of in vitro and in vivo models. We have also shown some of the possible DPs (Oleanolic acid, capsaicin, benzyl isothiocyanate, epigallocatechin gallate, phenethyl isothiocyanate and ursolic acid) that have shown miRNA regulatory activities and have not yet been tested against BC miRNAs. Finally, current limitations, challenges, future perspectives of DPs and BC research are also critically discussed.