Synergistic effects of cisplatin-caffeic acid induces apoptosis in human cervical cancer cells via the mitochondrial pathways

Cervical cancer (CxCa) is a major health problem globally and is associated with the presence of human papillomavirus infection. Cisplatin (CDDP) is a platinum-based chemotherapeutic agent. Owing to its side effects and drug-resistance, novel anticancer agents with lower toxicity, including caffeic acid (CFC), are of interest. However, the effects of CDDP and CFC in combination are, to the best of our knowledge, uninvestigated. The present study investigated the effectiveness of CDDP and CFC in combination and its mechanism of action on four human cervical cancer cell lines, which were compared with the Chlorocebus sabaeus normal kidney Vero cell line. Cell viability was evaluated using a sulforhodamine B assay. Caspase-Glo assay kits, measuring the activity of caspases-3, -7, -8 and -9, were used to detect caspase activation in HeLa and CaSki cell lines in response to CDDP and CFC in combination. The results revealed that CDDP and CFC alone reduced the proliferation of HeLa, CaSki, SiHa and C33A cell lines. Treatment with CFC exhibited no significant cytotoxicity towards Vero cells. In addition, CDDP-CFC significantly inhibited cell growth of HeLa and CaSki cell lines. In HeLa and CaSki cell lines, a combination index <1 for CDDP and CFC indicated the synergistic growth inhibition; the combination of the two also significantly increased expression of caspase-3, -7 and -9. In conclusion, CFC may be a candidate anticancer agent that, when use in combination, may increase the therapeutic efficacy of CDDP.

Cratoxy formosum leaf extract inhibits proliferation and migration of human breast cancer MCF-7 cells

In this study we investigated how Cratoxy formosum (CF) leaf extract affects the viability and migration of human breast cancer cells including the mechanism(s) responsible. Our results showed that CF leaf extract strongly induced MCF-7 cell death in a concentration- and time-dependent manner, with IC₅₀ values of 85.70±4.52μg/mL and 53.74±3.02μg/mL at 24h and 48h, respectively. Additionally, CF leaf extract potentiated the activity of 4 anticancer drugs with the greatest synergy occurring between CF and 5-FU. CF leaf extract also caused a dose-dependent decrease in colony forming ability with IC₅₀ values of 36.37+1.80 μg/mL and cell migration, with IC₅₀ values of 43.68±0.86μg/mL. Moreover, CF significantly induced ROS formation, increased caspase 3 activities, and reduced the mitochondrial membrane potential, leading to cancer cell apoptosis and cell death. In addition, the extract inhibited cancer cell migration at 25μg/mL by reducing MMP 2 and MMP 9 protein expression. Moreover, CF leaf extracts strongly decreased expression of the cell cycle regulatory protein Rac1 and downstream protein, cdk6. CF leaf extract significantly stimulated p21 and this correlated with a reduction in cyclin D1 protein levels. In summary, CF leaf extract can inhibit cell proliferation, induce cell apoptosis, and reduce cell migration in the MCF-7 cell line. It could also be beneficial for enhancing the activity of anticancer drugs used to treat breast cancer.

Cytotoxic and antimigratory effects of Cratoxy formosum extract against HepG2 liver cancer cells

The aim of the present study was to investigate the molecular mechanisms underlying Cratoxylum formosum (CF) Dyer-induced cancer cell death and antimigratory effects in HepG2 liver cancer cells. The cytotoxic, antiproliferative and antimigratory effects of CF leaf extract on human liver cancer HepG2 cell lines were evaluated using sulforhodamine B, colony formation, and wound healing assays. In addition, apoptosis induction mechanisms were investigated via reactive oxygen species (ROS) formation, caspase 3 activities, and mitochondrial membrane potential (ΔΨm) disruption. Gene expression and apoptosis-associated protein levels were measured by reverse transcription-quantitative polymerase chain reaction and western blotting. CF induced HepG2 cell death in a time- and dose-dependent manner with half maximal inhibitory concentration values of 219.03±9.96 and 124.90±6.86 µg/ml at 24 and 48 h, respectively. Treatment with CF caused a significant and dose-dependent decrease in colony forming ability and cell migration. Furthermore, the present study demonstrated that CF induced ROS formation, increased caspase 3 activities, decreased the ΔΨm, and caused HepG2 apoptosis. CF marginally decreased the expression level of the cell cycle regulatory protein, ras-related C3 botulinum toxin substrate 1 (rho family, small GTP binding protein Rac1) and the downstream protein, cyclin dependent kinase 6. Additionally, CF significantly enhanced p21 levels, reduced cyclin D1 protein levels and triggered cancer cell death. CF leaf extracts induced cell death, stimulated apoptosis and inhibited migration in HepG2 cells. Thus, CF may be useful for developing an anticancer drug candidate for the treatment of liver cancer.