Molecular Targets in Advanced Therapeutics of Cancers: The Role of Pharmacogenetics.

The advent of advanced molecular targeted therapy has resulted in improved prognoses for patients with advanced malignancies. However, despite the significant success and specificity of this advocated targeted therapy, significant on- and off-target adverse effects and inter-individual variability in treatment responses have been reported. The interpatient variability in drug response has been suggested to be partly due to variations in patient genomes. Therefore, the identification of genetic biomarkers by conducting pharmacogenetics studies can help predict patient responses to targeted therapy and may serve as a basis for individualized treatment. In this review, both clinically established and potential molecular targets are highlighted. Overall, current literature suggests that individualization of targeted therapy is promising; however, integrating the clinical benefits of identified biomarkers into clinical practice for personalized medicine remains a major challenge, and further studies to validate these markers and identify novel therapeutic approaches are needed.

The influence of genetic polymorphisms on the efficacy and side effects of anastrozole in postmenopausal breast cancer patients.

Breast cancer is a common cause of cancer mortality among women. Several genetic factors have been implicated in its development. Current treatment guidelines for estrogen receptor-positive breast cancer recommend that anastrozole [or any of the other two aromatase inhibitors (letrozole and exemestane)] is used as an alternative to tamoxifen or following several years of tamoxifen treatment. Nevertheless, this approach is still associated with many challenges, ranging from the recurrence of breast cancer to considerable interindividual variability in the tolerability of anastrozole, which may cause adverse effects, such as musculoskeletal symptoms, and lead to the withdrawal of many patients from treatment. Variabilities in the genes encoding the drug target (aromatase) or its metabolizing enzymes (CYP3A and UGT1A) contribute toward the interindividual variability in anastrozole's pharmacokinetics and/or pharmacodynamics. This paper reviews the role of genetic polymorphisms of CYP19A1, CYP3A4, and UGT1A4 in the responses of female hormone receptor-positive postmenopausal breast cancer patients to anastrozole. Many reviews in the literature have suggested that the study of functional polymorphisms and investigation of relevant genetic markers may provide valuable information in predicting responses to anastrozole in terms of its therapeutic and adverse effects. Nevertheless, more studies are required before the knowledge of its pharmacogenomics can be applied to the individualization of treatment to ensure that patients receive the maximum benefits. Therefore, future analyses, including but not limited to genome-wide association studies, are encouraged to address some of the gray areas in the pharmacogenomics of anastrozole therapy in postmenopausal breast cancer cases; this will help in providing guidance for future pharmacogenomics protocols when anastrozole is utilized in patients' management.

Iron deficiency and its epigenetic effects on iron homeostasis.

Iron deficiency is a common micronutrient deficiency associated with metabolic changes in the levels of iron regulatory proteins, hepcidin and ferroportin. Studies have associated dysregulation of iron homeostasis to other secondary and life-threatening diseases including anaemia, neurodegeneration and metabolic diseases. Iron deficiency plays a critical role in epigenetic regulation by affecting the Fe2+/α-ketoglutarate-dependent demethylating enzymes, Ten Eleven Translocase 1-3 (TET 1-3) and Jumonji-C (JmjC) histone demethylase, which are involved in epigenetic erasure of the methylation marks on both DNA and histone tails, respectively. In this review, studies involving epigenetic effects of iron deficiency associated with dysregulation of TET 1-3 and JmjC histone demethylase enzyme activities on hepcidin/ferroportin axis are discussed.

A review of molecular mechanisms of the anti-leukemic effects of phenolic compounds in honey.

Hematologic malignancies constitute about 9% of all new cases of cancers as reported via the GLOBOCAN series by International Agency for Research on Cancer (IARC) in 2008. So far, the conventional therapeutic and surgical approaches to cancer therapy have not been able to curtail the rising incidence of cancers, including hematological malignancies, worldwide. The last decade has witnessed great research interest in biological activities of phenolic compounds that include anticancer, anti-oxidation and anti-inflammation, among other things. A large number of anticancer agents combat cancer through cell cycle arrest, induction of apoptosis and differentiation, as well as through inhibition of cell growth and proliferation, or a combination of two or more of these mechanisms. Various phenolic compounds from different sources have been reported to be promising anticancer agents by acting through one of these mechanisms. Honey, which has a long history of human consumption both for medicinal and nutritional uses, contains a variety of phenolic compounds such as flavonoids, phenolic acids, coumarins and tannins. This paper presents a review on the molecular mechanisms of the anti-leukemic activity of various phenolic compounds on cell cycle, cell growth and proliferation and apoptosis, and it advocates that more studies should be conducted to determine the potential role of honey in both chemoprevention and chemotherapy in leukemia.

The Role of microRNAs in Alzheimer's Disease and Their Therapeutic Potentials.

MicroRNAs (miRNAs) are short, endogenous, non-coding RNAs that post-transcriptionally regulate gene expression by base pairing with mRNA targets. Altered miRNA expression profiles have been observed in several diseases, including neurodegeneration. Multiple studies have reported altered expressions of miRNAs in the brains of individuals with Alzheimer's disease (AD) as compared to those of healthy elderly adults. Some of the miRNAs found to be dysregulated in AD have been reported to correlate with neuropathological changes, including plaque and tangle accumulation, as well as altered expressions of species that are known to be involved in AD pathology. To examine the potentially pathogenic functions of several dysregulated miRNAs in AD, we review the current literature with a focus on the activities of ten miRNAs in biological pathways involved in AD pathogenesis. Comprehensive understandings of the expression profiles and activities of these miRNAs will illuminate their roles as potential therapeutic targets in AD brain and may lead to the discovery of breakthrough treatment strategies for AD.

Polyphenols as key players for the antileukaemic effects of propolis.

Propolis (a bee product) which has a long history of medicinal use by humans has attracted a great deal of research interest in the recent time; this is due to its widely reported biological activities such as antiviral, antifungal, antibacterial, anti-inflammatory, antioxidant, and anticarcinogenic properties. Crude form of propolis and its phenolic contents have both been reported to exhibit antileukaemic effects in various leukaemia cell lines. The ability of the polyphenols found in propolis to arrest cell cycle and induce apoptosis and differentiation in addition to inhibition of cell growth and proliferation makes them promising antileukaemic agents, and hence, they are believed to be a key to the antileukaemic effects of propolis in different types of leukaemia. This paper reviews the molecular bases of antileukaemic activity of both crude propolis and individual polyphenols on various leukaemia cell lines, and it indicates that propolis has the potential to be used in both treatment and prevention of leukaemia. This however needs further evaluation by in vitro, in vivo, and epidemiological studies as well as clinical trials.