Down-regulation and aberrant cytoplasmic expression of GLTSCR2 in prostatic adenocarcinomas

Characterization of HMGB1/2 Interactome in Prostate Cancer by Yeast Two Hybrid Approach: Potential Pathobiological Implications

High mobility group box B (HMGB) proteins are pivotal in the development of cancer. Although the proteomics of prostate cancer (PCa) cells has been reported, the involvement of HMGB proteins and their interactome in PCa is an unexplored field of considerable interest. We describe herein the results of the first HMGB1/HMGB2 interactome approach to PCa. Libraries constructed from the PCa cell line, PC-3, and from patients’ PCa primary tumor have been screened by the yeast 2-hybrid approach (Y2H) using HMGB1 and HMGB2 baits. Functional significance of this PCa HMGB interactome has been validated through expression and prognosis data available on public databases. Copy number alterations (CNA) affecting these newly described HMGB interactome components are more frequent in the most aggressive forms of PCa: those of neuroendocrine origin or castration-resistant PCa. Concordantly, adenocarcinoma PCa samples showing CNA in these genes are also associated with the worse prognosis. These findings open the way to their potential use as discriminatory biomarkers between high and low risk patients. Gene expression of a selected set of these interactome components has been analyzed by qPCR after HMGB1 and HMGB2 silencing. The data show that HMGB1 and HMGB2 control the expression of several of their interactome partners, which might contribute to the orchestrated action of these proteins in PCa

Abnormal Expression of PICT-1 and Its Codon 389 Polymorphism Is a Risk Factor for Human Endometrial Cancer

OBJECTIVE

The protein interacting with carboxyl terminus-1 (PICT-1) gene has been implicated as a tumor suppressor gene, and its alterations have been reported in several cancers. This study investigated the association of PICT-1 alterations with endometrial carcinogenesis.

METHODS

We analyzed the entire coding region of the PICT-1 gene using polymerase chain reaction-single-strand conformation polymorphism and DNA sequencing to examine PICT-1 mutations in endometrial cancer. Western blotting and immunohistochemical staining were performed to analyze the protein expression and cellular localization of PICT-1 in endometrial cancer cell lines and patient samples.

RESULTS

The codon 389 polymorphism of PICT-1 increased the risk of endometrial cancer. Interestingly, 2 of 13 endometrial cancers somatically acquired this mutation compared to normal counterparts. Immunohistochemical staining revealed lower levels of PICT-1 in samples from atypical endometrial hyperplasia and endometrial cancer tissues compared to normal endometrial tissues (p < 0.01). This decrease in PICT-1 expression was significantly correlated with histological grade and lymph node metastasis (p < 0.05).

CONCLUSIONS

The findings of this study suggest that disruption of PICT-1 protein expression and codon 389 polymorphism can contribute to the pathogenesis or neoplastic progression of endometrial cancer.

The protein interacting with carboxyl terminus-1 codon 389 polymorphism impairs protein interacting with carboxyl terminus-1 function and is a risk factor for uterine cervical cancer

PICT-1 is a nucleolar protein with various tumor suppressor functions. Recently, PICT-1 expression was reported to be dramatically reduced in several cancers. To investigate the role of PICT-1 in uterine cervical carcinogenesis, we examined its gene mutations, protein expression, cellular localization, and effect on p53 stabilization. PCR-SSCP analysis of the entire coding region of PICT-1 showed that a polymorphism at codon 389 may increase the risk of uterine cervical cancers, and also identified a novel missense mutation. Expression of wild-type PICT-1 inhibited the degradation of p53 in the presence or absence of HPV 18 E6 viral protein in vitro, while the expression of codon 389 polymorphic PICT-1 had a diminished inhibitory effect on p53 degradation. Moreover, we observed that PICT-1 degradation was induced both independently and cooperatively by E6 and E7 proteins from high-risk HPVs, but only marginal degradation was observed with proteins from low-risk HPV. Immunohistochemical staining of tumor samples revealed that lower levels of PICT-1 were observed in samples from CIN III and cervical cancer tissues, compared to normal cervical epithelium and CIN I, II tissues (P < 0.05). The reduction of PICT-1 may therefore be an early event in uterine cervical tumorigenesis. Our results indicated that PICT-1 counteracts HPV-induced p53 degradation and that aberrant PICT-1 function may contribute towards inactivating p53. Therefore, PICT-1 may play a critical role during the pathogenesis of uterine cervical cancers.

Suppression of GLTSCR2 expression in renal cell carcinomas

Nucleolar protein PICT-1/GLTSCR2 (GLTSCR2) has both tumor suppressive and oncogenic activities, depending on the types of cancer tissue and its expression level. The role of GLTSCR2 in renal cell carcinoma (RCC) has not yet been addressed. The aims of this study were to evaluate GLTSCR2 expression in RCC tissue and to determine pathological significance of GLTSCR2 in terms of tumor grade. RCC and adjacent normal tissue from 84 different patients was retrieved from nephrectomy specimens. The expression level of GLTSCR2 in RCC tissues was determined via immunohistochemical staining and invasion was determined using transwell chambers with Matrigel-coated membranes. The expression of GLTSCR2 was suppressed in about 80% of the carcinoma specimens compared to noncancerous renal tissue and inversely correlated with Fuhrman nuclear grade (r=-0.40, p<0.05). Knockdown of GLTSCR2 expression increased the invasiveness of SNU267 RCC cells. The expression of GLTSCR2 was suppressed in RCCs and its downregulation accentuated the malignant phenotype.

The expression of GLTSCR2 in cervical intra-epithelial lesion and cancer

BACKGROUND

GLTSCR2 was originally identified as a candidate tumor suppressor in several types of cancers. The present study was to investigate the expression pattern of GLTSCR2 in different cervical lesion tissues, appraise its potential role in cervical cancerogenesis.

METHODS

225 histologically confirmed samples representing a wide range of cervical disease processes were studied in this study using immunohistochemistry (IHC).

RESULTS

Compared with normal cervix and low-grade cervical intra-epithelial neoplasia (CIN I), cervical cancer and high-grade cervical intra-epithelial neoplasia (CIN II-III) tissues had lower expression scores of IHC staining of GLTSCR2. The positive staining signals of GLTSCR2 in CIN were decreased according to the grades of the intra-epithelial lesions. The IHC scores of GLTSCR2 in cervical cancer tissues were significantly lower than that in adjacent normal tissues. Different from previous report, we also found that GLTSCR2 was expressed in both nucleus and cytoplasm of cervical tissues, and the cytoplasmic expression of GLTSCR2 was observed in almost all tissues.

CONCLUSIONS

We demonstrated the GLTSCR2 expression decreased with the rise of the grade of cervical lesions. GLTSCR2 may play an important role in carcinogenesis of cervical cancer.