beta 1C Integrin expression in human endometrial proliferative diseases

Cell adhesion molecules in endometrial cancer - A systematic review

Adhesive molecules are responsible for the cell-cell interaction and the surrounding intercellular environment creating normal tissue architecture. The role of adhesion proteins in cancer refers to angiogenesis, loss of tissue continuity, and deprivation of intercellular contact with the extracellular matrix, promoting the spread of cancer through the formation of metastases. The integrity of the epithelium is disturbed - with disturbances in the whole mechanism of cell connections, thanks to which cancer cells infiltrate surrounding tissues, and move to lymphatic and blood vessels. Adhesive molecules are divided into five main families: cadherin, catenins, integrins, the immunoglobulin superfamily and non-classical adhesion molecules. In the present review we describe the role of all five families of adhesive molecules in endometrial cancer.

Regulation of the expression of CLU isoforms in endometrial proliferative diseases

Clusterin (CLU) is a nearly ubiquitous multifunctional protein synthesized in different functionally divergent isoforms, sCLU and nCLU, playing a crucial role by keeping a balance between cell proliferation and death. Studying in vivo CLU expression we found a higher mRNA expression both in neoplastic and hyperplastic tissues in comparison to normal endometria; in particular, by RT-qPCR we demonstrated an increase of the specific sCLU isoform in the neoplastic and hyperplastic endometrial diseases. On the contrary, no CLU increase was detected at the protein level. The CLU gene transcriptional activity was upregulated in the hyperplastic and neoplastic tissues, indicating the existence of a fine post-trans-criptional regulation of CLU expression possibly responsible for the protein decrease in the malignant disease. A specific CLU immunoreactivity was present in all the endometrial glandular cells in comparison to the other cellular compartments where CLU immunoreactivity was lower or absent. In conclusion, our results suggest the existence of a complex regulatory mechanism of CLU gene expression during the progression from normal to malignant cells, possibly contributing to endometrial carcinogenesis. Moreover, the specific alteration of the sCLU:nCLU ratio associated with the pathological stage, suggests a possible usage of CLU as molecular biomarker for the diagnosis/prognosis of endometrial proliferative diseases.

Alternative splicing of tumor suppressors and oncogenes

Alternative splicing is a fundamental mechanism to modulate gene expression programs in response to different growth and environmental stimuli. There is now ample evidence that alternative splicing errors, caused by mutations in cis-acting elements and defects and/or imbalances in trans-acting factors, may be causatively associated to cancer progression. Recent work indicates the existence of an intricate network of interactions between alternative splicing events and signal transduction pathways. In this network, splicing factors occupy a central position and appear to function both as targets and effectors of regulatory circuits. Thus, a change in their activity deeply affects alternative splicing profiles and hence the cell behavior. Here, we discuss a number of cases that exemplify the involvement of deregulated alternative splicing in tumor progression.

Cancer-Associated Perturbations in Alternative Pre-messenger RNA Splicing

For most of our 25,000 genes, the removal of introns by pre-messenger RNA (pre-mRNA) splicing represents an essential step toward the production of functional messenger RNAs (mRNAs). Alternative splicing of a single pre-mRNA results in the production of different mRNAs. Although complex organisms use alternative splicing to expand protein function and phenotypic diversity, patterns of alternative splicing are often altered in cancer cells. Alternative splicing contributes to tumorigenesis by producing splice isoforms that can stimulate cell proliferation and cell migration or induce resistance to apoptosis and anticancer agents. Cancer-specific changes in splicing profiles can occur through mutations that are affecting splice sites and splicing control elements, and also by alterations in the expression of proteins that control splicing decisions. Recent progress in global approaches that interrogate splicing diversity should help to obtain specific splicing signatures for cancer types. The development of innovative approaches for annotating and reprogramming splicing events will more fully establish the essential contribution of alternative splicing to the biology of cancer and will hopefully provide novel targets and anticancer strategies. Metazoan genes are usually made up of several exons interrupted by introns. The introns are removed from the pre-mRNA by RNA splicing. In conjunction with other maturation steps, such as capping and polyadenylation, the spliced mRNA is then transported to the cytoplasm to be translated into a functional protein. The basic mechanism of splicing requires accurate recognition of each extremity of each intron by the spliceosome. Introns are identified by the binding of U1 snRNP to the 5' splice site and the U2AF65/U2AF35 complex to the 3' splice site. Following these interactions, other proteins and snRNPs are recruited to generate the complete spliceosomal complex needed to excise the intron. While many introns are constitutively removed by the spliceosome, other splice junctions are not used systematically, generating the phenomenon of alternative splicing. Alternative splicing is therefore the process by which a single species of pre-mRNA can be matured to produce different mRNA molecules (Fig. 1). Depending on the number and types of alternative splicing events, a pre-mRNA can generate from two to several thousands different mRNAs leading to the production of a corresponding number of proteins. It is now believed that the expression of at least 70 % of human genes is subjected to alternative splicing, implying an enormous contribution to proteomic diversity, and by extension, to the development and the evolution of complex animals. Defects in splicing have been associated with human diseases (Caceres and Kornblihtt, Trends Genet 18(4):186-93, 2002, Cartegni et al., Nat Rev Genet 3(4):285-98, 2002, Pagani and Baralle, Nat Rev Genet 5(5):389-96, 2004), including cancer (Brinkman, Clin Biochem 37(7):584-94, 2004, Venables, Bioessays 28(4):378-86, 2006, Srebrow and Kornblihtt, J Cell Sci 119(Pt 13):2635-2641, 2006, Revil et al., Bull Cancer 93(9):909-919, 2006, Venables, Transworld Res Network, 2006, Pajares et al., Lancet Oncol 8(4):349-57, 2007, Skotheim and Nees, Int J Biochem Cell Biol 39:1432-1449, 2007). Numerous studies have now confirmed the existence of specific differences in the alternative splicing profiles between normal and cancer tissues. Although there are a few cases where specific mutations are the primary cause for these changes, global alterations in alternative splicing in cancer cells may be primarily derived from changes in the expression of RNA-binding proteins that control splice site selection. Overall, these cancer-specific differences in alternative splicing offer an immense potential to improve the diagnosis and the prognosis of cancer. This review will focus on the functional impact of cancer-associated alternative splicing variants, the molecular determinants that alter the splicing decisions in cancer cells, and future therapeutic strategies.

Regulation of TGF-β1 expression by androgen deprivation therapy of prostate cancer

In this paper we studied the in vivo neoadjuvant Androgen Deprivation Therapy (ADT) effect on the expression of TGF-β1 and its receptor Tβ-RII. Mechanisms of androgen dependence are critical to understanding prostate cancer progression to androgen independence associated with disease mortality, and TGF-β is thought to support prostatic apoptosis as its expression coincides with androgen ablation in benign and cancer tissues. Increase of both mRNA and protein level were shown for the first time only in the patients who underwent neoadjuvant ADT for 1-month. This transient increase of TGF-β expression after androgen ablation suggested cooperation of the pathways in prostate regression. Since no alteration was observed in the gene transcriptional activity, the molecular mechanism of this cooperation, probably act at the post-transcriptional level. TGF-β1 and Tβ-RII specific signals were co-localized within the neoplastic prostate epithelium. Our results suggests that the androgens deprivation by means of ADT for 1-month, involves a shift of the TGF-β1 mechanism in prostate cancer, suggesting that the TGF-β1 promotes prostate epithelial cell proliferation and inhibits apoptosis in a autocrine way.

Overexpression of a member of the pentraxin family (PTX3) in human soft tissue liposarcoma

A unique feature of human soft tissue liposarcoma is a stable (12;16)(q13;p11) translocation observed mainly in myxoid and roundcell liposarcomas. This translocation results in FUS/CHOP fusion transcripts with a corresponding oncogenic protein. We hypothesised that genes downstream of FUS/CHOP might serve as attractive candidates for novel tumour associated antigens. Among a panel of analysed genes, only pentraxin related gene (PTX3) demonstrated high expression in liposarcomas as compared to normal tissues. The analysis of RNA and protein expression demonstrated concordant results. However, the level of RNA and protein overexpression did not correlate in all cases. Finally, PTX3 expression was not related to presence of a FUS/CHOP fusion transcript within the liposarcoma tissues. PTX3 has been associated with adipocyte differentiation and now, additionally, is characterised by a markedly increased expression in human soft tissue liposarcoma. This finding mandates further research efforts to clarify the exact role of PTX3 in liposarcoma oncogenesis.

Holistic and network analysis of meningioma pathogenesis and malignancy

Meningiomas, which originate from arachnoid cells and constitute the largest subgroup of all intracranial tumors, are generally benign, yet have the capacity to progress into a higher histological grade of malignancy associated with an increase in biological aggressivity and/or capacity to recur. To elucidate meningioma pathogenesis and malignancy, we applied a holistic and network approach analyzing cDNA and tissue microarray results. A potential pathway leading to meningioma angiogenesis, apoptosis and proliferation was evidenced as well as a regulatory network of the biomarkers including Ki-67, AR, CD34, P53, c-MYC, etc. which might support clinical research. In this potential pathway, ITGB1 could be the most important "superoncogene" playing a vital role in apoptosis and proliferation, while FOXO3A, MDM4 and MT3 are important to the malignancy process. Some genes are first reported that could explain why radiation induces meningioma and why more female than male patients are affected. Further, we present the hypothesis that HIV-Tat protein might have a close relationship with meningioma pathogenesis and malignancy.

Aberrant and Alternative Splicing in Cancer

Pre-mRNA splicing is a sophisticated and ubiquitous nuclear process, which is a natural source of cancer-causing errors in gene expression. Intronic splice site mutations of tumor suppressor genes often cause exon-skipping events that truncate proteins just like classical nonsense mutations. Also, many studies over the last 20 years have reported cancer-specific alternative splicing in the absence of genomic mutations. Affected proteins include transcription factors, cell signal transducers, and components of the extracellular matrix. Antibodies against alternatively spliced products on cancer cells are currently in clinical trials, and competitive reverse transcription-PCR across regions of alternative splicing is being used as a simple diagnostic test. As well as being associated with cancer, the nature of the alternative gene products is usually consistent with an active role in cancer; therefore, the alternative splicing process itself is a potential target for gene therapy.