Loss of Expression of PTEN is Associated with Worse Prognosis in Patients with Cancer

Downregulation of STRAP promotes tumor growth and metastasis in hepatocellular carcinoma via reducing PTEN level

The serine-threonine kinase receptor-associated protein (STRAP) has been implicated in multiple human cancers. However, its expression and function are currently unclear and controversial in different tissue types. In the present study, we report that aberrant downregulation of STRAP in hepatocellular carcinoma (HCC) facilitated tumor cell growth and metastasis in a phosphatase and tensin homologue (PTEN)-dependent manner. Immunohistochemical analysis and quantitative real-time polymerase chain reaction results indicated that STRAP was frequently downregulated in HCC samples. Functionally, knockdown of STRAP by RNA inference in HCC cells promoted proliferation and migration in vitro and tumorigenicity and lung metastasis in vivo. Through detecting the expression of some tumor-related genes using western blot analysis, we found the tumor suppressor PTEN was decreased upon STRAP silencing. Further analyses demonstrated that silenced STRAP led to PTEN protein degradation. Immunohistochemical analysis revealed that STRAP expression was closely associated with PTEN expression in 30 cases of HCC samples. These findings strongly suggest that STRAP plays an inhibitory role in HCC via regulating PTEN expression and could be a potential therapeutic target for this disease. © 2017 IUBMB Life, 70(2):120-128, 2018.

Voltage-gated calcium channels: Novel targets for cancer therapy

Voltage-gated calcium channels (VGCCs) comprise five subtypes: The L-type; R-type; N-type; P/Q-type; and T-type, which are encoded by α₁ subunit genes. Calcium ion channels also have confirmed roles in cellular functions, including mitogenesis, proliferation, differentiation, apoptosis and metastasis. An association between VGCCs, a reduction in proliferation and an increase in apoptosis in prostate cancer cells has also been reported. Therefore, in the present study, the online clinical database Oncomine was used to identify the alterations in the mRNA expression level of VGCCs in 19 cancer subtypes. Overall, VGCC family genes exhibited under-expression in numerous types of cancer, including brain, breast, kidney and lung cancers. Notably, the majority of VGCC family members (CACNA1C, CACNA1D, CACNA1A, CACNA1B, CACNA1E, CACNA1H and CACNA1I) exhibited low expression in brain tumors, with mRNA expression levels in the top 1–9% of downregulated gene rankings. A total of 5 VGCC family members (CACNA1A, CACNA1B, CACNA1E, CACNA1G and CACNA1I) were under-expressed in breast cancer, with a gene ranking in the top 1–10% of the low-expressed genes compared with normal tissue. In kidney and lung cancers, CACNA1S, CACNA1C, CACNA1D, CACNA1A and CACNA1H exhibited low expression, with gene rankings in the top 1–8% of downregulated genes. In conclusion, the present findings may contribute to the development of new cancer treatment approaches by identifying target genes involved in specific types of cancer.

Novel Investigations of Flavonoids as Chemopreventive Agents for Hepatocellular Carcinoma

We would like to highlight the application of natural products to hepatocellular carcinoma (HCC). We will focus on the natural products known as flavonoids, which target this disease at different stages of hepatocarcinogenesis. In spite of the use of chemotherapy and radiotherapy in treating HCC, patients with HCC still face poor prognosis because of the nature of multidrug resistance and toxicity derived from chemotherapy and radiotherapy. Flavonoids can be found in many vegetables, fruits, and herbal medicines that exert their different anticancer effects via different intracellular signaling pathways and serve as antioxidants. In this review, we will discuss seven common flavonoids that exert different biological effects against HCC via different pathways.