Piperine-chlorogenic acid hybrids modulate critical regulators of the cell cycle and inhibit the proliferation of melanoma cells

Abstract

Melanoma is considered the most aggressive form of skin cancer due to its high metastatic potential. Despite the introduction of new therapeutic approaches such as immunotherapy and target-directed therapies, the mortality rate remains high. Intrinsic and acquired tumor resistance represents a challenger for melanoma treatment independently of the treatment schedule adopted. In this scenario, it is important to identify new drug candidates to improve therapeutic proposals for melanoma. Importantly, natural products have been used as scaffolds for drug design and development of new anticancer prototypes. In the present study, the antitumor potential of a series of piperine-chlorogenic acid hybrids was investigated. The synthesized substances were obtained by molecular hybridization of the piperine (1) and chlorogenic acid (2) pharmacophore fragments using a N-acylhydrazone subunit as linker (3). The compounds were assayed against melanoma cell lines (SK-MEL-147, WM-1366, CHL- 1), which are representative of different melanoma subtypes. Cell viability assay revealed that SK-MEL-147 was more responsive to treatments than WM-1366 and CHL-1 cell lines. Based on IC 50 values, PQM-277, PQM 281, and PQM 286 were the most active compounds. Further investigations showed that PQM-277 induces cell cycle arrest at G2/M, while the compounds PQM 281 and PQM 286 inhibit cell cycle progression at G1/S. The molecular mechanism associated with the antiproliferative activity of these substances on SK-MEL-147 was investigated. The data showed that PQM-277 modulates the expression of critical regulators for G2/M transition and mitosis onset. There was a reduction of mRNA abundance for CCNB1 (cyclin B1), CDK1, AURKA (Aurora A), AURKB (Aurora B), and PLK1. Conversely, the mRNA expression levels of CDKN1A (p21), a negative regulator of the cell cycle, were upregulated in samples treated with PQM-277 when compared to control groups. Concerning antiproliferative activity of PQM 281 and 286, we demonstrated that these substances inhibit cell cycle progression by inducing cyclins D and E downregulation. In addition, the pro-apoptotic activity of the compounds PQM-277, PQM-281, and PQM-286 on SK-MEL-147 cells was evidenced. There was a concomitant BAX upregulation and Bcl-2 downregulation in samples treated with PQM-277, that in turn, contributed to intrinsic apoptosis pathway activation. Taken together, the data obtained in this study demonstrate that piperine-chlorogenic acid hybrids are promising pre-clinic prototypes and should be considered for further in vivo investigation.