Celastrol Attenuates the Invasion and Migration and Augments the Anticancer Effects of Bortezomib in a Xenograft Mouse Model of Multiple Myeloma

FBXW7 in Cancer: What Has Been Unraveled Thus Far?

: The FBXW7 (F-box with 7 tandem WD40) protein encoded by the gene FBXW7 is one of the crucial components of ubiquitin ligase called Skp1-Cullin1-F-box (SCF) complex that aids in the degradation of many oncoproteins via the ubiquitin-proteasome system (UPS) thus regulating cellular growth. FBXW7 is considered as a potent tumor suppressor as most of its target substrates can function as potential growth promoters, including c-Myc, Notch, cyclin E, c-JUN, and KLF5. Its regulators include p53, C/EBP-δ, Numb, microRNAs, Pin 1, Hes-5, BMI1, Ebp2. Mounting evidence has indicated the involvement of aberrant expression of FBXW7 for tumorigenesis. Moreover, numerous studies have also shown its role in cancer cell chemosensitization, thereby demonstrating the importance of FBXW7 in the development of curative cancer therapy. This comprehensive review emphasizes on the targets, functions, regulators and expression of FBXW7 in different cancers and its involvement in sensitizing cancer cells to chemotherapeutic drugs.

Molecular Mechanisms of Action of Tocotrienols in Cancer: Recent Trends and Advancements

Tocotrienols, found in several natural sources such as rice bran, annatto seeds, and palm oil have been reported to exert various beneficial health promoting properties especially against chronic diseases, including cancer. The incidence of cancer is rapidly increasing around the world not only because of continual aging and growth in global population, but also due to the adaptation of Western lifestyle behaviours, including intake of high fat diets and low physical activity. Tocotrienols can suppress the growth of different malignancies, including those of breast, lung, ovary, prostate, liver, brain, colon, myeloma, and pancreas. These findings, together with the reported safety profile of tocotrienols in healthy human volunteers, encourage further studies on the potential application of these compounds in cancer prevention and treatment. In the current article, detailed information about the potential molecular mechanisms of actions of tocotrienols in different cancer models has been presented and the possible effects of these vitamin E analogues on various important cancer hallmarks, i.e., cellular proliferation, apoptosis, angiogenesis, metastasis, and inflammation have been briefly analyzed.

Pharmacological Utilization of Bergamottin, Derived from Grapefruits, in Cancer Prevention and Therapy

Cancer still remains one of the leading causes of death worldwide. In spite of significant advances in treatment options and the advent of novel targeted therapies, there still remains an unmet need for the identification of novel pharmacological agents for cancer therapy. This has led to several studies evaluating the possible application of natural agents found in vegetables, fruits, or plant-derived products that may be useful for cancer treatment. Bergamottin is a furanocoumarin derived from grapefruits and is also a well-known cytochrome P450 inhibitor. Recent studies have demonstrated potent anti-oxidative, anti-inflammatory, and anti-cancer properties of grapefruit furanocoumarin both in vitro and in vivo. The present review focuses on the potential anti-neoplastic effects of bergamottin in different tumor models and briefly describes the molecular targets affected by this agent.

Systematic identification of Celastrol-binding proteins reveals that Shoc2 is inhibited by Celastrol

Colorectal cancer (CRC) is the third most commonly diagnosed cancer. Celastrol exhibits anti-tumor activities in a variety of cancers. However, the effect of Celastrol on human CRC and the underlying mechanisms still need to be elucidated. The present study aimed to use in vitro and in vivo methods to clarify the anti-tumor effect of Celastrol and use protein microarrays to explore its mechanisms. We demonstrated that Celastrol effectively inhibited SW480 CRC cell proliferation. Two weeks of Celastrol gavage significantly inhibited the growth of xenografts in nude mice. A total of 69 candidate proteins were identified in the protein microarray experiment, including the most highly enriched protein Shoc2, which is a scaffold protein that modulates cell motility and metastasis through the ERK pathway. Celastrol significantly inhibited ERK1/2 phosphorylation in cell lines and xenograft tumors. Down-regulation of Shoc2 expression using Shoc2 siRNA also inhibited ERK1/2 phosphorylation. Furthermore, down-regulation of Shoc2 expression also significantly inhibited proliferation, colony formation, and migration functions of tumor cells. In addition, the LD0 of Celastrol by gavage is equal or more than 80 mg/kg in C57 male mice. In summary, we unraveled the anti-CRC function of Celastrol and confirmed for the first time that it inhibited the ERK1/2 pathway through binding to Shoc2.

Evidence for the Involvement of the Master Transcription Factor NF-κB in Cancer Initiation and Progression

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is responsible for the regulation of a large number of genes that are involved in important physiological processes, including survival, inflammation, and immune responses. At the same time, this transcription factor can control the expression of a plethora of genes that promote tumor cell proliferation, survival, metastasis, inflammation, invasion, and angiogenesis. The aberrant activation of this transcription factor has been observed in several types of cancer and is known to contribute to aggressive tumor growth and resistance to therapeutic treatment. Although NF-κB has been identified to be a major contributor to cancer initiation and development, there is evidence revealing its role in tumor suppression. This review briefly highlights the major mechanisms of NF-κB activation, the role of NF-κB in tumor promotion and suppression, as well as a few important pharmacological strategies that have been developed to modulate NF-κB function.