Vitamin E Analog α -TEA, Methylseleninic Acid, andTrans-Resveratrol in Combination Synergistically Inhibit Human Breast Cancer Cell Growth

Phytofabrication of Nanoparticles as Novel Drugs for Anticancer Applications

Cancer is one of the foremost causes of death globally and also the major stumbling block of increasing life expectancy. Although the primary treatment of surgical resection, chemotherapy, and radiotherapy have greatly reduced the mortality of cancer, the survival rate is still low because of the metastasis of tumor, a range of adverse drug reactions, and drug resistance. For all this, it is relevant to mention that a growing amount of research has shown the anticarcinogenic effect of phytochemicals which can modulate the molecular pathways and cellular events include apoptosis, cell proliferation, migration, and invasion. However, their pharmacological potential is hindered by their low water solubility, low stability, poor absorption, and rapid metabolism. In this scenario, the development of nanotechnology has created novel formulations to maximize the potential use of phytochemicals in anticancer treatment. Nanocarriers can enhance the solubility and stability of phytochemicals, prolong their half-life in blood and even achieve site-targeting delivery. This review summarizes the advances in utilizing nanoparticles in cancer therapy. In particular, we introduce several applications of nanoparticles combined with apigenin, resveratrol, curcumin, epigallocatechin-3-gallate, 6-gingerol, and quercetin in cancer treatment.

Resveratrol and cancer treatment: updates

Cancer, a growing health problem worldwide, affects millions of people every year. The overall survival rates of most cancers have been prolonged owing to the efforts of clinicians and scientists. However, some tumors develop resistance to chemoradiotherapeutic agents, and the cancer research community continues to search for effective sensitizers. Resveratrol, a natural polyphenolic phytoalexin, has shown promising effects in inhibiting proliferation and cancer progression in several tumor models. However, its molecular mechanisms and applications in chemotherapy and radiotherapy have yet to be fully determined. In this concise review, we highlight the role and related molecular mechanisms of resveratrol in cancer treatment. In particular, we focus on the role of resveratrol in the tumor microenvironment and the sensitization of cancer cells for chemotherapy and radiotherapy. Resveratrol shows promising efficacies in cancer treatment and may be applied in clinical therapy, but it requires further clinical study.

Development, Maintenance, and Reversal of Multiple Drug Resistance: At the Crossroads of TFPI1, ABC Transporters, and HIF1

Early detection and improved therapies for many cancers are enhancing survival rates. Although many cytotoxic therapies are approved for aggressive or metastatic cancer; response rates are low and acquisition of de novo resistance is virtually universal. For decades; chemotherapeutic treatments for cancer have included anthracyclines such as Doxorubicin (DOX); and its use in aggressive tumors appears to remain a viable option; but drug resistance arises against DOX; as for all other classes of compounds. Our recent work suggests the anticoagulant protein Tissue Factor Pathway Inhibitor 1α (TFPI1α) plays a role in driving the development of multiple drug resistance (MDR); but not maintenance; of the MDR state. Other factors; such as the ABC transporter drug efflux pumps MDR-1/P-gp (ABCB1) and BCRP (ABCG2); are required for MDR maintenance; as well as development. The patient population struggling with therapeutic resistance specifically requires novel treatment options to resensitize these tumor cells to therapy. In this review we discuss the development, maintenance, and reversal of MDR as three distinct phases of cancer biology. Possible means to exploit these stages to reverse MDR will be explored. Early molecular detection of MDR cancers before clinical failure has the potential to offer new approaches to fighting MDR cancer.

A potential role for resveratrol as a radiation sensitizer for melanoma treatment

BACKGROUND

Radiotherapy (XRT) is used to improve local control of melanoma and for palliation of metastatic disease. Clinical use of XRT for melanoma is often limited by extent of disease and the relative radioresistance of melanoma may limit the effectiveness of XRT. Our group and others have previously shown that resveratrol (RSV) enhances radiation sensitivity in radioresistant prostate cancer cell lines.

MATERIAL AND METHODS

In this study, the effects of XRT in combination with RSV on radioresistant melanoma lines, SK-Mel-5 and HTB-65, were evaluated by assessment of proliferation and apoptosis. Clonogenic assay, comparison of proliferating cell nuclear antigen staining, Quick Cell Proliferation assay, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and caspase-3 activity assay were used to assess proliferation and apoptosis, as appropriate.

RESULTS

We found that the percentage of colonies, proliferating cell nuclear antigen + cells and the optical density value of melanoma cells were decreased after addition of RSV to XRT (XRT/RSV). TUNEL + cells and the relative caspase-3 activity in melanoma cells were increased after addition of RSV to XRT (XRT/RSV). We investigated the possible molecular mechanisms of decreased proliferation and increased apoptosis by using reverse transcriptase-polymerase chain reaction and immunohistochemical staining. The anti-proliferative effect of XRT/RSV correlated with decreased expression of pro-proliferative molecule cyclin B, cyclin D, cdk2 and cdk4. The pro-apoptotic effect of XRT/RSV correlated with decreased expression of the anti-apoptotic molecule FLIP, Bcl-2, and survivin.

CONCLUSION

These data suggest that RSV enhances radiation sensitivity of melanoma cells by inhibiting proliferation and promoting apoptosis. Resveratrol may have a potential role as a radiation sensitizer for melanoma treatment.

α-TEA-induced death receptor dependent apoptosis involves activation of acid sphingomyelinase and elevated ceramide-enriched cell surface membranes

BACKGROUND

Alpha-tocopherol ether-linked acetic acid (α-TEA), an analog of vitamin E (RRR-alpha-tocopherol), is a potent and selective apoptosis-inducing agent for human cancer cells in vivo and in vitro. α-TEA induces apoptosis via activation of extrinsic death receptors Fas (CD95) and DR5, JNK/p73/Noxa pathways, and suppression of anti-apoptotic mediators Akt, ERK, c-FLIP and survivin in breast, ovarian and prostate cancer cells.

RESULTS

In this study, we demonstrate that α-TEA induces the accumulation of cell surface membrane ceramide, leading to co-localization with Fas, DR5, and FADD, followed by activation of caspases-8 and -9 and apoptosis in human MDA-MB-231 breast cancer cells. α-TEA treatment leads to increased acid sphingomyelinase (ASMase) activity by 30 min, peaking at 4 hrs, which is correlated with ASMase translocation from cytosol to the cell surface membrane. Functional knockdown of ASMase with either the chemical inhibitor, desipramine, or siRNA markedly reduces α-TEA-induced cell surface membrane accumulation of ceramide and its co-localization with Fas, DR5, and FADD, cleavage of caspases-8 and -9 and apoptosis, suggesting an early and critical role for ASMase in α-TEA-induced apoptosis. Consistent with cell culture data, immunohistochemical analyses of tumor tissues taken from α-TEA treated nude mice bearing MDA-MB-231 xenografts show increased levels of cell surface membrane ceramide in comparison to tumor tissues from control animals.

CONCLUSION

Taken together, these studies demonstrate that ASMase activation and membrane ceramide accumulation are early events contributing to α-TEA-induced apoptosis in vitro and perhaps in vivo.