Concomitant high expression of ERα36, GRP78 and GRP94 is associated with aggressive papillary thyroid cancer behavior

The Isoforms of Estrogen Receptor Alpha and Beta in Thyroid Cancer

The incidence of thyroid cancer was predominant in women, indicating that the sex hormone may have a role in thyroid cancer development. Generally, the sex hormone exerts its function by binding to the correspondent nuclear receptors. Therefore, aberrant of these receptors may be involved in the development of thyroid cancer. Estrogen receptor alpha (ERα) and beta (ERβ), two main estrogen receptors, have been reported to have an important role in the pathogenesis of thyroid cancer. When the ERα and ERβ genes undergo the alternative RNA splicing, some ERα and ERβ isoforms with incomplete functional domains may be formed. To date, several isoforms of ERα and ERβ have been identified. However, their expression and roles in thyroid cancer are far from clear. In this review, we summarized the expressions and roles of ERα and ERβ isoforms in thyroid cancer, aiming to provide the perspective of modulating the alternative RNA splicing of ERα and ERβ against thyroid cancer.

Comprehensive analysis reveals GRP94 is associated with worse prognosis of breast cancer

BACKGROUND

Breast cancer (BC) is the most common cancer diagnosed in women around the world. Glucose-related protein 94 (GRP94) is a molecular chaperone on the endoplasmic reticulum (ER) that is associated with many malignancies, although its role in breast carcinogenesis has remained unclear. This study aimed to investigate the expression of GRP94 in BC and its relationship with BC clinicopathological features and prognosis based on a comprehensive analysis.

METHODS

The mutation and expression patterns of GRP94 in multiple cancers were elucidated from TCGA data. A GRP94 IS (immune score) was generated from breast tumors in Chinese women by multiplying the staining intensity and the percentage of positive cells. The relationship between GRP94 expression and clinicopathological parameters in TMA samples was identified by Spearman correlation analysis. We established a GRP94 co-expression interaction network from two databases (TCGA and STRING). Overall survival (OS) and relapse-free survival (RFS) were determined via the KM-plotter analysis platform.

RESULTS

GRP94 is mutated in most cancer types, and the average mutation frequency is 1.1%. GRP94 expression in BC was in the middle of the expression levels of the analyzed cancer types. The protein level of GRP94 was significantly higher in BC tissues than in normal breast tissues. A high level of GRP94 was positively associated with the levels of PR and AR and negatively associated with the level of EGFR but was not associated with age, pathological types, pathological grades, clinical stages or the levels of ER, HER2, P53, Ki67, or CK5/6. High expression of GRP94 predicted decreased OS and RFS in BC. The cluster analysis of the GRP94 gene coexpression network showed six dominant biological events, including ribosome biogenesis, amino acid activation, ER stress, protein folding and protein localization to the nucleus, cell cycle processes and ubiquitin-protein ligase activity involved in the mitotic cell cycle.

CONCLUSIONS

The study suggests that GRP94 could be a potential prognostic factor in BC.

MicroRNA-99a-3p/GRP94 axis affects metastatic progression of human papillary thyroid carcinoma by regulating ITGA2 expression and localization

Papillary thyroid cancer (PTC) usually has favorable prognosis; however, distant metastasis is a leading cause of death associated with PTC. MicroRNA-99a-3p (miR-99a-3p) is a member of the miR-99 family that is shown to be a tumor suppressor in various human cancers including the anaplastic thyroid cancer, another type of thyroid cancer. The Cancer Genome Atlas database and our previous study reported that miR-99a-3p is downregulated in human PTC tissues as well as human papillary thyroid carcinoma B-CPAP and TPC-1 cell lines. However, its pathological role in PTC remains unclear, especially its impact on PTC metastasis. In the present study, the role of miR-99a-3p in PTC metastasis was molecularly evaluated in in vitro and in vivo models. Our functional study revealed that overexpressing miR-99a-3p significantly suppresses epithelial-mesenchymal transition (EMT) and anoikis resistance as well as migration and invasion of B-CPAP and TPC-1 cells. The mechanical study indicated that glucose-regulated protein 94 (GRP94) is the direct target of miR-99a-3p. Moreover, GRP94 overexpression reverses the inhibitory effect of miR-99a-3p on PTC metastasis. In addition, the miR-99a-3p/GRP94 axis exerts its effect via inhibiting the expression and cytoplasmic relocation of integrin 2α (ITGA2). Furthermore, in vivo experiments confirmed that miR-99a-3p significantly inhibits tumor growth and lung metastasis in PTC xenograft mice. Overall, our findings suggested that the miR-99a-3p/GRP94/ITGA2 axis may be a novel therapeutic target for the prevention of PTC metastasis.

Molecular Chaperones and Thyroid Cancer

Thyroid cancers are the most common of the endocrine system malignancies and progress must be made in the areas of differential diagnosis and treatment to improve patient management. Advances in the understanding of carcinogenic mechanisms have occurred in various fronts, including studies of the chaperone system (CS). Components of the CS are found to be quantitatively increased or decreased, and some correlations have been established between the quantitative changes and tumor type, prognosis, and response to treatment. These correlations provide the basis for identifying distinctive patterns useful in differential diagnosis and for planning experiments aiming at elucidating the role of the CS in tumorigenesis. Here, we discuss studies of the CS components in various thyroid cancers (TC). The chaperones belonging to the families of the small heat-shock proteins Hsp70 and Hsp90 and the chaperonin of Group I, Hsp60, have been quantified mostly by immunohistochemistry and Western blot in tumor and normal control tissues and in extracellular vesicles. Distinctive differences were revealed between the various thyroid tumor types. The most frequent finding was an increase in the chaperones, which can be attributed to the augmented need for chaperones the tumor cells have because of their accelerated metabolism, growth, and division rate. Thus, chaperones help the tumor cell rather than protect the patient, exemplifying chaperonopathies by mistake or collaborationism. This highlights the need for research on chaperonotherapy, namely the development of means to eliminate/inhibit pathogenic chaperones.

CCNA1 gene as a potential diagnostic marker in papillary thyroid cancer

The malignancy that most affects the endocrine system is thyroid neoplasm, with an increasing incidence over the years. The most prevalent histological type of the carcinomas that affect the thyroid gland is papillary carcinoma with a prevalence of 80 % worldwide. The current diagnostic methodology may present inconclusive results, emphasizing the need for new effective and sensitive techniques to aid the diagnosis. For this, it is necessary to understand molecular and protein mechanisms in the identification of diagnostic and predictive markers in the lesions. The Cyclin A1 protein, encoded by the CCNA1 gene, is an important cell cycle regulator, belonging to the MAPK/ERK signaling pathway directly involved with thyroid cancer. The aim of this study was to evaluate the CCNA1 gene and Cyclin A1 protein expression in papillary thyroid carcinoma, follicular thyroid carcinoma, and benign thyroid lesions, by real time quantitative PCR and immunohistochemistry analysis, respectively, to verify their roles as potential diagnostic and predictive markers to future applications in the clinical routine. Overexpression of CCNA1 gene was observed in the papillary carcinoma group compared to the normal group (P = 0.0023), benign lesions (P = 0.0011), colloid goiter (P = 0.0124), and follicular carcinoma (P = 0.0063). No differential expression was observed in the papillary primary tumor group from negative lymph nodes compared with the one from positive lymph nodes (P = 0.3818). Although an increased expression of Cyclin A1 was observed in the PTC group compared to the other one in the IHC analysis, no significant difference was observed (Fisher's exact Test). A Cyclin A1 overexpression was detected with weak to mid-moderate immunoreactivity in the benign group (k = 0.56), (score 1.5); mid-moderate to moderate in the goiter group (k = 0.58); weak in the FTC group (k = 0.33); and mid-moderate to moderate in the PTC group (k = 0.48). Due to the small sample size in the IHC analysis and to the fact that not all RNA is translated into protein, the diagnostic potential of Cyclin A1 could not be assessed. However, these findings highlight the potential of the CCNA1 gene as a diagnostic marker for papillary thyroid carcinoma.

Tunicamycin promotes metastasis through upregulating endoplasmic reticulum stress induced GRP78 expression in thyroid carcinoma

Background

Thyroid cancer (TC) is the most common type of endocrine malignancy and its incidence is increasing over years. Conventional surgery, radiotherapy and chemotherapy are difficult to improve the significant effects of it due to aggression and metastasis of poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC), and these are regarded as the most malignant types of TC. Glucose-regulated protein (GRP78) is the key molecule of tumor growth, apoptosis and metastasis. However, the underlying mechanisms of GRP78 in TC still require discussion. This study aimed to explore the role of GRP78 and its potential mechanism in TC.

Results

GRP78 expression was increased in TC tissues when compared with adjacent normal tissues. Besides, down-regulation of GRP78 significantly inhibited the metastatic and proliferative ability of ATC cells in in vitro studies. In addition, tunicamycin-induced ER stress up-regulated the expression of GRP78, PERK and XBP1 as well as reversed the metastatic ability of GRP78 in ATC cells. Bioinformatics and statistical analysis of gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for RNA-sequencing data with regard to si-GRP78 and si-control showed that GRP78 might regulate the ability of metastasis through extracellular matrix (ECM) remodeling in ATC cells, as well as the expression of ECM components such as COL1A1 and MMP13, which were highly relevant to ATC cells. The analysis of GEPIA database confirmed that high genomic amplification of MMP13 and COL1A1 in TC tissues showed correlation with TNM stage. Further western blotting analysis showed that MMP13 might be the target of GRP78 in ATC cells and ER stress could activate the expression of MMP13 that is suppressed by GRP78 depletion.

Conclusions

GRP78 acts as an important regulator of metastasis under ER stress. In addition, the function of GRP78 might be mediated by ECM remodeling in ATC cells, implicating it as a therapeutic target in TC.

BCAP31, a cancer/testis antigen-like protein, can act as a probe for non-small-cell lung cancer metastasis

Non-small-cell lung cancer (NSCLC) represents most of lung cancers, is often diagnosed at an advanced metastatic stage. Therefore, exploring the mechanisms underlying metastasis is key to understanding the development of NSCLC. The expression of B cell receptor-associated protein 31 (BCAP31), calreticulin, glucose-regulated protein 78, and glucose-regulated protein 94 were analyzed using immunohistochemical staining of 360 NSCLC patients. It resulted that the high-level expression of the four proteins, but particularly BCAP31, predicted inferior overall survival. What’s more, BCAP31 was closely associated with histological grade and p53 status, which was verified by seven cohorts of NSCLC transcript microarray datasets. Then, three NSCLC cell lines were transfected to observe behavior changes BCAP31 caused, we found the fluctuation of BCAP31 significantly influenced the migration, invasion of NSCLC cells. To identify the pathway utilized by BCAP31, Gene Set Enrichment Analysis was firstly performed, showing Akt/m-TOR/p70S6K pathway was the significant one, which was verified by immunofluorescence, kinase phosphorylation and cellular behavioral observations. Finally, the data of label-free mass spectroscopy implied that BCAP31 plays a role in a fundamental biological process. This study provides the first demonstration of BCAP31 as a novel prognostic factor related to metastasis and suggests a new therapeutic strategy for NSCLC.

Heat shock proteins in thyroid malignancies: Potential therapeutic targets for poorly-differentiated and anaplastic tumours?

Thyroid cancer is the most common endocrine malignancy, with well-differentiated subtypes characterized by an excellent prognosis due to their optimal sensitivity to standard therapies whereas poorly differentiated and anaplastic tumours by chemo/radio-resistance and unfavourable outcome. Heat Shock Proteins (HSPs) are molecular chaperones overexpressed in thyroid malignancies and involved in crucial functions responsible for thyroid carcinogenesis, as protection from apoptosis, drug resistance and cell migration. Thus, HSPs inhibitors have been proposed as novel therapeutic agents in thyroid cancer to revert molecular mechanisms of tumour progression. In this review, we report an overview on the biological role of HSPs, and specifically HSP90s, in thyroid cancer and their potential involvement as biomarkers. We discuss the rationale to evaluate HSPs inhibitors as innovative anticancer agents in specific subtypes of thyroid cancer characterized by poor response to therapies with the objective to target single family chaperones to reduce, simultaneously, the expression/stability of multiple client proteins.

GM2-GM3 gangliosides ratio is dependent on GRP94 through down-regulation of GM2-AP cofactor in brain metastasis cells

GRP94 is an ATP-dependent chaperone able to regulate pro-oncogenic signaling pathways. Previous studies have shown a critical role of GRP94 in brain metastasis (BrM) pathogenesis and progression. In this work, an untargeted lipidomic analysis revealed that some lipid species were altered in GRP94-deficient cells, specially GM2 and GM3 gangliosides. The catalytic pathway of GM2 is affected by the low enzymatic activity of β-Hexosaminidase (HexA), responsible for the hydrolysis of GM2 to GM3. Moreover, a deficiency of the GM2-activator protein (GM2-AP), the cofactor of HexA, is observed without alteration of gene expression, indicating a post-transcriptional alteration of GM2-AP in the GRP94-ablated cells. One plausible explanation of these observations is that GM2-AP is a client of GRP94, resulting in defective GM2 catabolic processing and lysosomal accumulation of GM2 in GRP94-ablated cells. Overall, given the role of gangliosides in cell surface dynamics and signaling, their imbalance might be linked to modifications of cell behaviour acquired in BrM progression. This work indicates that GM2-AP could be an important factor in ganglioside balance maintenance. These findings highlight the relevance of GM3 and GM2 gangliosides in BrM and reveal GM2-AP as a promising diagnosis and therapeutic target in BrM research.

Co-downregulation of GRP78 and GRP94 Induces Apoptosis and Inhibits Migration in Prostate Cancer Cells

Background

Both glucose-regulated protein 78 kDa (GRP78) and glucose-regulated protein 94 kDa (GRP94) are important molecular chaperones that play critical roles in maintaining tumor survival and progression. This study investigated the effects in prostate cancer cells following the downregulation of GRP78 and GRP94.

Methods

RNA interference was used to downregulate GRP78 and GRP94 expression in the prostate cancer cell line, PC-3. The effects on apoptosis and cell migration was examined along with expression of these related proteins.

Results

Small interfering RNAs targeting GRP78 and GRP94 successfully down-regulated their expression. This resulted in the induction of apoptosis and inhibition of cell migration. Preliminary mechanistic studies indicated that caspase-9 (cleaved) and Bax expression levels were upregulated while Bcl-2 and vimentin expression levels were downregulated.

Conclusion

Co-downregulation of GRP78 and GRP94 expression induces apoptosis and inhibits migration in prostate cancer cells.