Toxicity of C60 fullerene-cisplatin nanocomplex against Lewis lung carcinoma cells.

Cisplatin (Cis-Pt) is the cytotoxic agent widely used against tumors of various origin, but its therapeutic efficiency is substantially limited by a non-selective effect and high toxicity. Conjugation of Cis-Pt with nanocarriers is thought to be one option to enable drug targeting. The aim of this study was to estimate toxic effects of the nanocomplex formed by noncovalent interaction of C60 fullerene with Cis-Pt against Lewis lung carcinoma (LLC) cells in comparison with free drug. Scanning tunneling microscopy showed that the minimum size of C60-Cis-Pt nanoparticles in aqueous colloid solution was 1.1 nm whereas that of C60 fullerene was 0.72 nm, thus confirming formation of the nanocomplex. The cytotoxic effect of C60-Cis-Pt nanocomplex against LLC cells was shown to be higher with IC50 values 3.3 and 4.5 times lower at 48 h and 72 h, respectively, as compared to the free drug. 12.5 µM Cis-Pt had no effect on LLC cell viability and morphology while C60-Cis-Pt nanocomplex in Cis-Pt-equivalent concentration substantially decreased the cell viability, impaired their shape and adhesion, inhibited migration and induced accumulation in proapoptotic subG1 phase. Apoptosis induced by the C60-Cis-Pt nanocomplex was confirmed by caspase 3/7 activation and externalization of phosphatidylserine on the outer surface of LLC cells with the double Annexin V-FITC/PI staining. We assume that C60 fullerene as a component of the C60-Cis-Pt nanocomplex promoted Cis-Pt entry and intracellular accumulation thus contributing to intensification of the drug's toxic effect against lung cancer cells.

Berberine alkaloids inhibit the proliferation and metastasis of breast carcinoma cells involving Wnt/ß-catenin signaling and EMT.

Berberine alkaloids belong to the class of isoquinoline alkaloids that have been shown to possess anticancer potential, berberine exhibits inhibitory effects on breast cancer development. However, the exact mechanisms of action for anti-breast carcinoma of the alkaloids, including epiberberine, berberrubine and dihydroberberine are still unclear. MTT assay, colony formation, wound healing and transwell invasion assays detected these alkaloids suppressed proliferation, migration and invasion of breast cancer cells. Hoechst and Annexin V-FITC/PI staining were used to analyze the apoptosis of breast cancer cells. Western blotting investigated the changes noted in the expression levels of the key proteins involved in the Wnt/ß-catenin signaling pathway and epithelial to mesenchymal transition (EMT). The results showed that inhibited the proliferation of breast cancer cells. Berberine alkaloids inhibited the cell cycle at G2/M phase in MCF-7 cells, but in MDA-MB-231 cells berberine alkaloids arrested the cell cycle in G0/G1 and G2/M phases. By decreasing ß-catenin expression, increasing GSK-3ß expression and decreasing N-cadherin expression, increasing E-cadherin expression, which proved that epiberberine, berberrubine and dihydroberberine inhibited of metastasis of breast cancer cells through Wnt signaling pathway and reversed EMT except berberine. Furthermore, berberine alkaloids exert their anti-breast cancer effects through the synergistic action of intrinsic and extrinsic pathways of apoptosis. These findings highlight the different effects of different berberine alkaloids on breast cancer cells and confirm that berberine alkaloids may be potentially used in the treatment of breast cancer.

Nanocomplex of Berberine with C60 Fullerene Is a Potent Suppressor of Lewis Lung Carcinoma Cells Invasion In Vitro and Metastatic Activity In Vivo.

Effective targeting of metastasis is considered the main problem in cancer therapy. The development of herbal alkaloid Berberine (Ber)-based anticancer drugs is limited due to Ber' low effective concentration, poor membrane permeability, and short plasma half-life. To overcome these limitations, we used Ber noncovalently bound to C60 fullerene (C60). The complexation between C60 and Ber molecules was evidenced with computer simulation. The aim of the present study was to estimate the effect of the free Ber and C60-Ber nanocomplex in a low Ber equivalent concentration on Lewis lung carcinoma cells (LLC) invasion potential, expression of epithelial-to-mesenchymal transition (EMT) markers in vitro, and the ability of cancer cells to form distant lung metastases in vivo in a mice model of LLC. It was shown that in contrast to free Ber its nanocomplex with C60 demonstrated significantly higher efficiency to suppress invasion potential, to downregulate the level of EMT-inducing transcription factors SNAI1, ZEB1, and TWIST1, to unblock expression of epithelial marker E-cadherin, and to repress cancer stem cells-like markers. More importantly, a relatively low dose of C60-Ber nanocomplex was able to suppress lung metastasis in vivo. These findings indicated that сomplexation of natural alkaloid Ber with C60 can be used as an additional therapeutic strategy against aggressive lung cancer.

Mode of photoexcited C60 fullerene involvement in potentiating cisplatin toxicity against drug-resistant L1210 cells.

Introduction: C60 fullerene has received great attention as a candidate for biomedical applications. Due to unique structure and properties, C60 fullerene nanoparticles are supposed to be useful in drug delivery, photodynamic therapy (PDT) of cancer, and reversion of tumor cells' multidrug resistance. The aim of this study was to elucidate the possible molecular mechanisms involved in photoexcited C60 fullerene-dependent enhancement of cisplatin toxicity against leukemic cells resistant to cisplatin. Methods: Stable homogeneous pristine C60 fullerene aqueous colloid solution (10-4 М, purity 99.5%) was used in the study. The photoactivation of C60 fullerene accumulated by L1210R cells was done by irradiation in microplates with light-emitting diode lamp (420-700 nm light, 100 mW·cm-2). Cells were further incubated with the addition of Cis-Pt to a final concentration of 1 µg/mL. Activation of p38 MAPK was visualized by Western blot analysis. Flow cytometry was used for the estimation of cells distribution on cell cycle. Mitochondrial membrane potential (Δψm) was estimated with the use of fluorescent potential-sensitive probe TMRE (Tetramethylrhodamine Ethyl Ester). Results: Cis-Pt applied alone at 1 µg/mL concentration failed to affect mitochondrial membrane potential in L1210R cells or cell cycle distribution as compared with untreated cells. Activation of ROS-sensitive proapoptotic p38 kinase and enhanced content of cells in subG1 phase were detected after irradiation of L1210R cells treated with 10-5M C60 fullerene. Combined treatment with photoexcited C60 fullerene and Cis-Pt was followed by the dissipation of Δψm at early-term period, blockage of cell transition into S phase, and considerable accumulation of cells in proapoptotic subG1 phase at prolonged incubation. Conclusion: The effect of the synergic cytotoxic activity of both agents allowed to suppose that photoexcited C60 fullerene promoted Cis-Pt accumulation in leukemic cells resistant to Cis-Pt. The data obtained could be useful for the development of new approaches to overcome drug-resistance of leukemic cells.