The expression of the high mobility group I(Y) mRNA in thyroid cancers: useful tool of differential diagnosis of thyroid nodules

HMGA1 in cancer: Cancer classification by location

The high mobility group A1 (HMGA1) gene plays an important role in numerous malignant cancers. HMGA1 is an oncofoetal gene, and we have a certain understanding of the biological function of HMGA1 based on its activities in various neoplasms. As an architectural transcription factor, HMGA1 remodels the chromatin structure and promotes the interaction between transcriptional regulatory proteins and DNA in different cancers. Through analysis of the molecular mechanism of HMGA1 and clinical studies, emerging evidence indicates that HMGA1 promotes the occurrence and metastasis of cancer. Within a similar location or the same genetic background, the function and role of HMGA1 may have certain similarities. In this paper, to characterize HMGA1 comprehensively, research on various types of tumours is discussed to further understanding of the function and mechanism of HMGA1. The findings provide a more reliable basis for classifying HMGA1 function according to the tumour location. In this review, we summarize recent studies related to HMGA1, including its structure and oncogenic properties, its major functions in each cancer, its upstream and downstream regulation associated with the tumourigenesis and metastasis of cancer, and its potential as a biomarker for clinical diagnosis of cancer.

Enhanced expression of HMG-Y proteins in proliferating tissues

The high mobility group (HMG) proteins I and Y are well characterised non-histone chromosomal proteins which bind to A-T rich regions of DNA and regulate gene expression and/or DNA replication. A correlation has been demonstrated between the increased expression of HMG-Y proteins and malignancy. However, it is not known whether the expression of HMGs particularly, the Y group, is a function of proliferation rate. In the present study, we have used normal tissues of calf testes, thymus and liver. The results show distinctly high expression of HMG-Y proteins in testes than in thymus and the expression was practically undetectable in liver. The results suggest that even in normal tissues there is a direct correlation between the proliferation rate and the expression of the HMG-Y proteins, which can partly explain its increased expression in cancer.

Roles of HMGA proteins in cancer

The high mobility group A (HMGA) non-histone chromatin proteins alter chromatin structure and thereby regulate the transcription of several genes by either enhancing or suppressing transcription factors. This protein family is implicated, through different mechanisms, in both benign and malignant neoplasias. Rearrangements of HMGA genes are a feature of most benign human mesenchymal tumours. Conversely, unrearranged HMGA overexpression is a feature of malignant tumours and is also causally related to neoplastic cell transformation. Here, we focus on the role of the HMGA proteins in human neoplastic diseases, the mechanisms by which they contribute to carcinogenesis, and therapeutic strategies based on targeting HMGA proteins.

High-mobility group protein 1(Y): Metastasis-associated or metastasis-inducing?

Metastasis is the major cause of mortality and morbidity for patients with cancer. The high-mobility group protein 1(Y) [HMG-1(Y)] has a role in the transcription of many genes involved at different steps in the metastatic cascade and has been linked with cancer in human and animal models. This may represent a potential therapeutic target for patients. The following review summarizes and critically appraises the evidence for the role of HMG-1(Y) in metastasis.

Molecular pathogenesis of thyroid cancer

A number of molecular abnormalities have been described in association with the progression from normal thyroid tissue to benign adenomas to well-differentiated and finally anaplastic epithelial thyroid cancer. These include upregulation of proliferative factors, such as growth hormones and oncogenes, downregulation of apoptotic and cell-cycle inhibitory factors, such as tumor suppressors, disruption of normal cell-to-cell interactions, and cellular immortalization. The progression model for thyroid carcinoma has not been proven, but evidence suggests that an evolutionary molecular process is involved, especially in the development of follicular thyroid cancers for which there are distinct intermediate phenotypes. We present a comprehensive evaluation of factors involved in thyroid tumorigenesis and attempt to describe preliminary attributes of a progression model. The organization of this model should also provide a template for the incorporation of new information as it is derived from large-scale genomic studies.

A water-extract of the Korean traditional formulation Geiji-Bokryung-Hwan reduces atherosclerosis and hypercholesteremia in cholesterol-fed rabbits

Geiji-Bokryung-Hwan (GBH), a drug preparation consisting of five herbs of Cinnamomi Ramulus (Geiji), Poria Cocos (Bokryun), Mountan Cortex Radicis (Mokdanpi), Paeoniae Radix (Jakyak) and Persicae Semen (Doin), is a traditional Korean herbal medicine that is widely used in the treatment of atherosclerosis-related disorders. A water extract of GBH was found to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and inhibit low-density lipoprotein (LDL) oxidation more effectively than probucol, a well-known commercially available antioxidant. In order to evaluate the anti-atherogenic potential of this medication, New Zealand White (NZW) rabbits were fed a normal diet for 12 weeks, a high cholesterol diet, a high cholesterol diet containing 1% probucol or a high cholesterol diet containing 5% water-soluble extract of GBH. Both GBH and probucol reduced plasma cholesterol levels. LDLs from the GBH-treated group were more resistant to Cu(2+)-induced oxidation and contained more vitamin E than LDLs from the high cholesterol diet group. Endothelial damage, determined at week 6, was reduced by 55% in the GBH group (P<0.01). GBH treatment reduced an atherosclerotic area in the abdominal aorta by 58% (P<0.05) and cholesterol deposition in the thoracic aorta by 55% (P<0.05). The severity of atherosclerosis in the GBH group was significantly reduced after an adjustment using cholesterol exposure as an index of the cholesterol-lowering effect. On the other hand, diet-induced hyperlipidemic rabbits were given water extract of GBH in doses of 50 (Group B) and 200 mg/kg (Group C) and compared with controls (Group A). At 40 days after intervention in groups A, B and C, total and LDL cholesterol levels were significantly lowered (P<0.01). LDL/high density lipoprotein (HDL) ratio was also significantly decreased (P<0.01). This study concludes that the reduction in atherosclerosis by GBH relies not only on its cholesterol-lowering effect but also more heavily on its antioxidant potential, which prevents endothelial damage and inhibits LDL oxidative modification in hypercholesterolemic animals.

Thyroid nodules: diagnosis and therapy

Less than 1% of all cancers are present in the thyroid, yet thyroid nodules are found in 4 to 10% of the adult population. Because thyroid nodules are relatively common, the diagnostic dilemma is to distinguish between a more common benign nodule, which usually does not require specific treatment, and a malignant nodule, which requires thyroidectomy and further treatment. Thyroid nodules usually are an incidental finding on a routine examination by a primary care physician. When patients seek treatment for symptomatic nodules, a more serious problem may be indicated, and thyroid cancer is suggested. However, additional studies have demonstrated the use of genetic markers and immunohistochemistry in the diagnosis of thyroid nodules, which may lead to a more rational approach to the treatment. This article reviews literature published in the last 12 months pertaining to the pathogenesis, diagnosis, and treatment of thyroid nodules.

Elevated levels of high-mobility-group chromosomal proteins, HMGA1, in murine skin carcinoma

The high-mobility-group, HMGA1 (formerly HMGI(Y)) chromosomal proteins are known to be involved in gene regulation and their high expression is associated with neoplastic transformation of cells and metastatic tumor progression. Here, we present our results on the expression of HMGA1 in murine skin carcinoma as detected by acid-urea electrophoresis, reverse-phase high-performance liquid chromatography and Western blot. The enhanced expression of HMGA1 proteins directly correlates with the extent of cellular atypia and neoplastic changes noticed in the histopathology of tumor and suggest a potential use of these proteins as marker for determining the grade of skin tumor.

Genetic imbalances in preleukemic thymuses

To understand the molecular mechanisms involved in preleukemia, the suppression subtractive hybridization method was used in a murine radiation-induced thymic lymphoma model. Seventeen mRNAs overexpressed in preleukemic thymuses were identified: mouse laminin binding protein (p40/37LBP), E25 protein, Rattus norvegicus clone BB.1.4.1, profilin, poly(A) binding protein (PABP), mouse high mobility group protein 1, topoisomerase I, clusterin, proteasome RC1 subunit, rat prostatein C3 and C1 subunits; two ESTs and four unknown genes. The overexpression of PABP, clusterin, profilin, and the p40/37LBP mRNAs was confirmed in preleukemic thymuses and can be related to some cellular events observed during the preleukemic period, i.e., alterations of cell cycle and apoptosis properties. The p40/37LBP and 67-kDa laminin receptor proteins were upregulated during the preleukemic period. The data suggest that additional studies on p40/37LBP and 67-kDa laminin receptor regulation are required to evaluate their potential role in the lymphoma prevention by TNF-alpha and IFN-gamma.