Cis-trimethoxystilbene, exhibits higher genotoxic and antiproliferative effects than its isomer trans-trimethoxystilbene in MCF-7 and MCF-10A cell lines.

Stilbenes are a class of natural compounds with a wide variety of biological effects, such as antitumor activity. The best-known stilbene is resveratrol, whose clinical application is limited due to its low bioavailability. Methoxylated derivatives of this stilbene, including cis-trimethoxystilbene (cis-TMS) and trans-trimethoxystilbene (trans-TMS) have demonstrated more pronounced cytotoxic and anti-proliferative effects than resveratrol. Thus, the objective of this study is to evaluate and compare the cytotoxicity and antiproliferative effects of cis- and trans-TMS in MCF-7 and its normal counterpart MCF-10A. Both compounds were cytotoxic, genotoxic, and induced G2-M accumulation and cell death in the two cell lines. These results suggested that the genotoxicity of cis- and trans-TMS is involved in the reduction of cellular proliferation of MCF-7 and MCF-10A cells, but notably, such antiproliferative effects are more pronounced for cis- than trans-TMS.

Effect of diterpenoid kaurenoic acid on genotoxicity and cell cycle progression in gastric cancer cell lines.

The goal of our study was to evaluate the effect of kaurenoic acid, obtained from copaiba oil resin, in gastric cancer (GC) and a normal mucosa of stomach (MNP01) cell lines. The compound was tested at concentrations of 2.5, 5, 10, 30 and 60µg/mL. Comet and micronucleus assays were used to access its potential genotoxicity in vitro. Moreover, we evaluated the effect of kaurenoic acid in cell cycle progression and in the transcription of genes involved in the control of the cell cycle: MYC, CCND1, BCL2, CASP3, ATM, CHK2 and TP53. Kaurenoic acid induced an increase on cell DNA damage or micronucleus frequencies on GC cell lines in a dose-dependent manner. The GC and MNP01 cell lines entering DNA synthesis and mitosis decreased significantly with kaurenoic acid treatment, and had an increased growth phase compared with non-treated cells. The treatment induced apoptosis (or necrosis) even at a concentration of 2.5µg/mL in relation to non-treated cells. GC cell lines presented reduced MYC, CCND1, BCL2 and CASP3 transcription while ATM, CHK2 and TP53 increased in transcription in relation to non-treated cells, especially at a concentration above 10µg/mL. The gene transcription in the MNP01 (non-treated non-cancer cell line) was designated as a calibrator for all the GC cell lines. In conclusion, our results showed that kaurenoic acid obtained from Copaifera induces DNA damage and increases the micronuclei frequency in a dose-dependent manner in GC cells, with a significant genotoxicity observed above the concentration of 5µg/mL. Moreover, this compound seems to be able to induce cell cycle arrest and apoptosis in GC cells.

(-)-Hinokinin Induces G2/M Arrest and Contributes to the Antiproliferative Effects of Doxorubicin in Breast Cancer Cells.

Breast cancer incidence rises worldwide and new chemotherapeutical strategies have been investigated to overcome chemoresistance. (-)-Hinokinin is a dibenzylbutyrolactone lignan derived from the partial synthesis of (-)-cubebin extracted from Piper cubeba seeds. Biological effects of dibenzylbutyrolactone lignans include antiviral, antitumor, anti-inflammatory, and trypanocidal activities. In the present study, we evaluated the ability of (-)-hinokinin to modulate the antiproliferative effects of doxorubicin intumoral (MCF-7 and SKBR-3) and normal (MCF-10 A) breast cell lines. Treatment with (-)-hinokinin did not affect the cellular proliferation or contribute to the antitproliferative effects of doxorubicin in MCF-10 A cells. After 24 and 48 hours of treatment with (-)-hinokinin, MCF-7 and SKBR-3 were accumulated in G2/M and, when combined with doxorubicin, (-)-hinokinin contributed to the antiproliferative effects of this chemotherapic by modulation of the cyclin-dependent kinase inhibitor 1. Apoptotic cell death was observed in response to (-)-hinokinin alone in MCF-7, but not in SKBR-3 even 72 hours after treatment. In MCF-7, doxorubicin-induced apoptosis was not increased by (-)-hinokinin. The findings of the present study suggest (-)-hinokinin as an antiproliferative agent that contributes to the effects of doxorubicin. (-)-Hinokinin modulates apoptotic cell death via the molecular regulation of the cell cycle and apoptotic control genes, but the cellular genetic background directly affects the cell fate decision in response to treatment.