REVIEW ARTICLES
Retinoic acid being the most active metabolite of vitamin A (retinol) regulates the wide spectrum of physiological processes including embryonic development, development of immune response, hematopoiesis, glucose and lipids metabolism, etc. Retinoic acid participates in the regulation of such important aspects of life-sustaining activity as cell differentiation, proliferation and programmed cell death. This review is focused on comparison of two highly homological members of lipid-binding proteins family, CRABP1 and CRABP2. Although binding of retinoic acid is the only known function of these proteins the physiological meaning this interaction seems to be rather different. CRABBP2 binding of retinoic acid leads to the activation of RAR / RXR nuclear receptors, that act as transcription factors, and further stimulation of expression of numerous retinoic responsive genes. The meaning of CRABP1 binding of retinoic acid is less clear. Some data evidences for the similar action of CRABP1 and CRABP2 in regard to the potentiation of the retinoic acid effect, while the majority of data points on the opposite role of CRABP1, that is reduction of intracellular concentration of retinoic acid and / or decrease of retinoic acid bioavailability through the potentiation of its catabolism or sequestration in the cytosol. The most recent publications also suggest some additional functions of these proteins that could be independent of retinoic acid signalling. The data concerning the roles of these proteins in carcinogenesis and tumor progression are contradictive as well.
This review covers the functions of retinoic acid as well as the molecular mechanisms mediating its activity including the different aspects of retinoic acid receptors activity. The review also comprises the comparative structural-functional analysis of CRABP proteins and probable mechanisms of their intracellular activity including those associated with retinoic acid signalling and retinoic acid-independent. A special attention is drawn to the analysis of the data on the involvement of CRABP proteins in the carcinogenesis and tumor progression. The data pointing on either oncogenic or tumor-suppressive functions are given for each protein.
Prostate cancer (PC) represents the second most frequent type of tumor in men worldwide. Proteomics represents a promising approach for the discovery of new biomarkers able to improve the management of PC patients. Markers more specific and sensitive than prostate-specific antigen are needed for PC diagnosis, prognosis and response to treatment. Moreover, proteomics could represent an important tool to identify new molecular targets for PC tailored therapy. Now several possible PC biomarkers sources, each with advantages and limitations, are under investigation, including tissues, urine, serum, plasma and prostatic fluids. Innovative high-throughput proteomic platforms are now identifying and quantifying new specific and sensitive biomarkers for PC detection, stratification and treatment. Nevertheless, many putative biomarkers are still far from being applied in clinical practice.
This review aims to discuss the recent advances in PC proteomics, emphasizing biomarker discovery and their application to clinical utility for diagnosis and patient stratification.
RESEARCH ARTICLES
Epstein–Barr virus (EBV), a representative of the herpesvirus family, is the etiological agent for a number of benign and malignant human neoplasms. Among the latter, the nasopharyngeal carcinoma (NPC) occupies a special place. In NPC development EBV plays a key role stimulating the progression of the pathological process from precancerous lesions to the cancer development. For most NPC patients, elevated levels of humoral IgG and IgA antibodies against capsid and early EBV antigens are characteristic and their antibody titers rise to high levels long before the diagnosis of cancer. Using this phenomenon, virus-specific antibodies are used for many years as markers for NPC screening, especially in cases of undiagnosed primary lesion. In recent years, in endemic for NPC regions (South China, South-East Asia) a great attention has been paid to the use of quantitative determination of EBV DNA copies in the blood plasma of patients with NPC as a method of early cancer detection and monitoring.
The aim of this study was to compare clinical significance of EBV DNA and humoral antibodies levels in blood plasma of NPC patients in non-endemic region, Russia. The results obtained indicate that both markers DNA / EBV and IgA antibodies against capsid EBV antigens can be successfully used for diagnosis of NPC in non-endemic region. However, in comparison with the virus-specific antibody titers, the viral DNA levels in the patients plasma are more sensitive and specific as NPC marker reflecting the efficacy of the therapy, and the state of remission or relapse.
Leptin is a multifunctional hormone with the activity of cytokines, which regulates critical signaling pathways that can induce cell proliferation, invasion, angiogenesis and tumor growth. Leptin plays an important role in the regulation of metabolism, energy exchange, functions of the neuro-endocrine system, including the pituitary, hypothalamus, adrenals, and immune system functions. Recently, some evidences have been appeared concerning the role of leptin in induction of chronic inflammatory processes, autoimmune pathologies, type 2 diabetes and cancer. An elevated blood level of the hormone is considered as a risk factor for different neoplasm development
Objective. Analysis of the hormone leptin (Lep), the long and short isoforms of its receptor (LepR1 and LepR2) expression in blood, tumor cells and normal skin fibroblasts in the patients with metastatic cutaneous melanoma (CM) with various clinico-pathological characteristics for prognostic assessment.
Materials and methods. 15 patients with metastatic CM (10 women and 5 men, aged 22 to 67 years with body mass from normal to obese) have been studied. The expression of Lep / LepR in the patient and donor blood sera, tumor and normal skin fibroblasts were determined using enzyme-linked immunosorbent assay (ELISA) and RT PCR using total RNAs isolated from pairs of tumor samples and normal tissue.
Results. Average level of leptin in the blood of CM patients and in tumor cells exceeds the normal one. Concentration of lepin in female CM patients was higher than in male patients. The expression level of Lep and LepR1 genes (but not LepR2) in tumor cells was relatively higher than in normal skin fibroblasts of these patients, and above the level of GAPDH gene expression. In the female patients with overweight (body mass index = 25,00–29,99 kg/m2 ) there was a trend to higher concentrations of leptin in the blood in comparison of the patients with normal body mass and leptin level in the sera of male CM patients. Earlier revealed relationship between the concentration of leptin in blood and the level of expression of the long isoform of its receptor in tumor cells is confirmed.
AUTHORS’ DATA
ISSN 2413-3787 (Online)