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HSP90 is a vital chaperone protein conserved across all organisms. As a chaperone protein, it correctly folds client proteins. Structurally, this protein is a dimer with monomer subunits that consist of three main conserved domains known as the N-terminal domain, middle domain, and the C-terminal domain. Multiple isoforms of HSP90 exist, and these isoforms share high homology. These isoforms are present both within the cell and outside the cell. Isoforms HSP90α and HSP90ß are present in the cytoplasm; TRAP1 is present in the mitochondria; and GRP94 is present in the endoplasmic reticulum and is likely secreted due to post-translational modifications (PTM). HSP90 is also secreted into an extracellular environment via an exosome pathway that differs from the classic secretion pathway. Various co-chaperones are necessary for HSP90 to function. Elevated levels of HSP90 have been observed in patients with cancer. Despite this observation, the possible role of HSP90 in cancer was overlooked because the chaperone was also present in extreme amounts in normal cells and was vital to normal cell function, as observed when the drastic adverse effects resulting from gene knockout inhibited the production of this protein. Differences between normal HSP90 and HSP90 of the tumor phenotype have been better understood and have aided in making the chaperone protein a target for cancer drugs. One difference is in the conformation: HSP90 of the tumor phenotype is more susceptible to inhibitors. Since overexpression of HSP90 is a factor in tumorigenesis, HSP90 inhibitors have been studied to combat the adverse effects of HSP90 overexpression. Monotherapies using HSP90 inhibitors have shown some success; however, combination therapies have shown better results and are thus being studied for a more effective cancer treatment.
Assuntos
Proteínas de Choque Térmico HSP90/metabolismo , Chaperonas Moleculares/metabolismo , Neoplasias/metabolismo , Animais , Carcinogênese/metabolismo , Carcinogênese/patologia , Humanos , Neoplasias/patologia , Isoformas de Proteínas/metabolismoRESUMO
Cancer is one of the leading causes of death across the world. Although conventional cancer treatments such as chemotherapy and radiotherapy have effectively decreased cancer progression, they come with many dose-limiting side-effects. Phytochemicals that naturally occur in spices, fruits, vegetables, grains, legumes, and other common foods are surprisingly effective complements to conventional cancer treatments. These biologically active compounds demonstrate anticancer effects via cell signaling pathway interference in cancerous cells. In addition, phytochemicals protect non-cancerous cells from chemotherapy-induced side-effects. This paper addresses the not only the potential of phytochemicals quercetin, isoflavones, curcumin, catechins, and hesperidin in terms of cancer treatment and protection against side-effects of chemotherapy, but also methods for increasing phytochemical bioavailability.
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Obesity has long been associated with endometrial cancer amongst postmenopausal women; in fact, obese women are more than twice as likely to develop endometrial cancer as women of normal weight. The risk of developing this type of cancer increases with weight gains in adulthood, especially among women who did not use hormonal therapy for menopause. Thus, with an association between menopause, obesity, and endometrial cancer established, it prompts the following question: what specific factors could cause higher risk levels for endometrial cancer in this cohort of women? In this paper, the factor of hormonal changes and imbalances associated with both obesity and menopause will be examined. The hormones that will be discussed are insulin and insulin-like factors, estrogen, and adipokines (specifically adiponectin, visfatin, and leptin).
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Angiogenesis is a significant event in a wide range of healthy and diseased conditions. This process frequently involves vasodilation and an increase in vascular permeability. Numerous players referred to as angiogenic factors, work in tandem to facilitate the outgrowth of endothelial cells (EC) and the consequent vascularity. Conversely, angiogenic factors could also feature in pathological conditions. Angiogenesis is a critical factor in the development of tumors and metastases in numerous cancers. An increased level of angiogenesis is associated with decreased survival in breast cancer patients. Therefore, a good understanding of the angiogenic mechanism holds a promise of providing effective treatments for breast cancer progression, thereby enhancing patients' survival. Disrupting the initiation and progression of this process by targeting angiogenic factors such as vascular endothelial growth factor (Vegf)-one of the most potent member of the VEGF family- or by targeting transcription factors, such as Hypoxia-Inducible Factors (HIFs) that act as angiogenic regulators, have been considered potential treatment options for several types of cancers. The objective of this review is to highlight the mechanism of angiogenesis in diseases, specifically its role in the progression of malignancy in breast cancer, as well as to highlight the undergoing research in the development of angiogenesis-targeting therapies.
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Hypoxia-inducible factor-1α (HIF-1α) is known as a transactivator for VEGF gene promoter. It can be induced by hypoxia. However, no study has been done so far to dissect HIF-1α-mediated effects from hypoxia or VEGF-mediated effects. By using a HIF-1α knockout (HIF-1α KO) cell system in mouse embryonic fibroblast (MEF) cells, this study analyzes cell migration and HIF-1α, hypoxia and VEGF activation. A hypoxia-mediated HIF-1α induction and VEGF transactivation were observed: both HIF-1α WT lines had significantly increased VEGF transactivation, as an indicator for HIF-1α induction, in hypoxia compared to normoxia; in contrast, HIF-1α KO line had no increased VEGF transactivation under hypoxia. HIF-1α promotes cell migration: HIF-1α-KO cells had a significantly reduced migration compared to that of the HIF-1α WT cells under both normoxia and hypoxia. The significantly reduced cell migration in HIF-1α KO cells can be partially rescued by the restoration of WT HIF-1α expression mediated by adenoviral-mediated gene transfer. Interestingly, hypoxia has no effect on cell migration: the cells had a similar cell migration rate under hypoxic and normoxic conditions for both HIF-1α WT and HIF-1α KO lines, respectively. Collectively, these data suggest that HIF-1α plays a role in MEF cell migration that is independent from hypoxia-mediated effects.
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Prostate cancer is the most frequently diagnosed malignancy in American men, and a more aggressive form of the disease is particularly prevalent among African Americans. The therapeutic success rate for prostate cancer can be tremendously improved if the disease is diagnosed early. Thus, a successful therapy for this disease depends heavily on the clinical indicators (biomarkers) for early detection of the presence and progression of the disease, as well as the prediction after the clinical intervention. However, the current clinical biomarkers for prostate cancer are not ideal as there remains a lack of reliable biomarkers that can specifically distinguish between those patients who should be treated adequately to stop the aggressive form of the disease and those who should avoid overtreatment of the indolent form.A biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. A biomarker reveals further information to presently existing clinical and pathological analysis. It facilitates screening and detecting the cancer, monitoring the progression of the disease, and predicting the prognosis and survival after clinical intervention. A biomarker can also be used to evaluate the process of drug development, and, optimally, to improve the efficacy and safety of cancer treatment by enabling physicians to tailor treatment for individual patients. The form of the prostate cancer biomarkers can vary from metabolites and chemical products present in body fluid to genes and proteins in the prostate tissues.Current advances in molecular techniques have provided new tools facilitating the discovery of new biomarkers for prostate cancer. These emerging biomarkers will be beneficial and critical in developing new and clinically reliable indicators that will have a high specificity for the diagnosis and prognosis of prostate cancer. The purpose of this review is to examine the current status of prostate cancer biomarkers, with special emphasis on emerging markers, by evaluating their diagnostic and prognostic potentials. Both genes and proteins that reveal loss, mutation, or variation in expression between normal prostate and cancerous prostate tissues will be covered in this article. Along with the discovery of prostate cancer biomarkers, we will describe the criteria used when selecting potential biomarkers for further development towards clinical use. In addition, we will address how to appraise and validate candidate markers for prostate cancer and some relevant issues involved in these processes. We will also discuss the new concept of the biomarkers, existing challenges, and perspectives of biomarker development.
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IMPORTANCE OF THE FIELD: Cancer is both a major health concern and a care-cost issue in the US and the rest of the world. It is estimated that there will be a total of 1,479,350 new cancer cases and 562,340 cancer deaths in 2009 within the US alone. One of the major obstacles in cancer therapy is the ability to target specifically cancer cells. Most existing chemotherapies and other routine therapies (such as radiation therapy and hormonal manipulation) use indiscriminate approaches in which both cancer cells and non-cancerous surrounding cells are treated equally by the toxic treatment. As a result, either the cancer cell escapes the toxic dosage necessary for cell death and consequently resumes replication, or an adequate lethal dose that kills the cancer cell also causes the cancer patient to perish. Owing to this dilemma, cancer- or organ/tissue-specific targeting is greatly desired for effective cancer treatment and the reduction of side effect cytotoxicity within the patient. AREAS COVERED IN THIS REVIEW: In this review, the strategies of targeted cancer therapy are discussed, with an emphasis on viral-based gene delivery and regulated gene expression. WHAT THE READER WILL GAIN: Numerous approaches and updates in this field are presented for several common cancer types. TAKE HOME MESSAGE: A summary of existing challenges and future directions is also included.