Hook1 inhibits malignancy and epithelial–mesenchymal transition in hepatocellular carcinoma

Protein homeostasis maintained by HOOK1 levels promotes the tumorigenic and stemness properties of ovarian cancer cells through reticulum stress and autophagy

BACKGROUND

Ovarian cancer has a high mortality rate mainly due to its resistance to currently used therapies. This resistance has been associated with the presence of cancer stem cells (CSCs), interactions with the microenvironment, and intratumoral heterogeneity. Therefore, the search for new therapeutic targets, particularly those targeting CSCs, is important for improving patient prognosis. HOOK1 has been found to be transcriptionally altered in a substantial percentage of ovarian tumors, but its role in tumor initiation and development is still not fully understood.

METHODS

The downregulation of HOOK1 was performed in ovarian cancer cell lines using CRISPR/Cas9 technology, followed by growth in vitro and in vivo assays. Subsequently, migration (Boyden chamber), cell death (Western-Blot and flow cytometry) and stemness properties (clonal heterogeneity analysis, tumorspheres assay and flow cytometry) of the downregulated cell lines were analysed. To gain insights into the specific mechanisms of action of HOOK1 in ovarian cancer, a proteomic analysis was performed, followed by Western-blot and cytotoxicity assays to confirm the results found within the mass spectrometry. Immunofluorescence staining, Western-blotting and flow cytometry were also employed to finish uncovering the role of HOOK1 in ovarian cancer.

RESULTS

In this study, we observed that reducing the levels of HOOK1 in ovarian cancer cells reduced in vitro growth and migration and prevented tumor formation in vivo. Furthermore, HOOK1 reduction led to a decrease in stem-like capabilities in these cells, which, however, did not seem related to the expression of genes traditionally associated with this phenotype. A proteome study, along with other analysis, showed that the downregulation of HOOK1 also induced an increase in endoplasmic reticulum stress levels in these cells. Finally, the decrease in stem-like properties observed in cells with downregulated HOOK1 could be explained by an increase in cell death in the CSC population within the culture due to endoplasmic reticulum stress by the unfolded protein response.

CONCLUSION

HOOK1 contributes to maintaining the tumorigenic and stemness properties of ovarian cancer cells by preserving protein homeostasis and could be considered an alternative therapeutic target, especially in combination with inducers of endoplasmic reticulum or proteotoxic stress such as proteasome inhibitors.

Long non-coding RNA TPTEP1 exerts inhibitory effects on hepatocellular carcinoma by impairing microRNA-454-3p-mediated DLG5 downregulation

BACKGROUND

Hepatocellular carcinoma (HCC) is usually diagnosed at late stages, making it the second cause of malignancy-related death across the world. Long noncoding RNAs (lncRNAs) are of significance to tumorigenesis, highly suggestive of their functional roles as novel biomarkers for cancer therapy. The current study investigated the specific role of lncRNA TPTE pseudogene 1 (TPTEP1) in HCC.

METHODS

Expression of lncRNA TPTEP1, microRNA-454-3p (miR-454-3p) and discs large homolog 5 (DLG5) was determined in tissues samples from the recruited patients with HCC. Cell proliferation, migration and invasion assays were performed to determine effects of lncRNA TPTEP1, miR-454-3p and DLG5 on the malignant phenotype of tumor cells. Finally, the mouse HCC model was also established to disclose the tumor suppressor effects of lncRNA TPTEP1 in vivo.

RESULTS

LncRNA TPTEP1 was downregulated both in HCC cells and tissues, and played a negative regulatory role in HCC cell proliferation, migration and invasion. Mechanistically, lncRNA TPTEP1 competitively bound to miR-454-3p, thereby upregulating its endogenous target DLG5. Moreover, lncRNA TPTEP1 hindered activation of the protein kinase B signaling pathway, causing inhibited malignant phenotypes of HCC cells. Also, lncRNA TPTEP1 suppressed tumor growth and extrahepatic metastasis (lung) via miR-454-3p/DLG5 axis.

CONCLUSION

Taken together, this research revealed a concrete mechanism of lncRNA TPTEP1 in HCC.

The EMT modulator SNAI1 contributes to AML pathogenesis via its interaction with LSD1

Modulators of epithelial-to-mesenchymal transition (EMT) have recently emerged as novel players in the field of leukemia biology. The mechanisms by which EMT modulators contribute to leukemia pathogenesis, however, remain to be elucidated. Here we show that overexpression of SNAI1, a key modulator of EMT, is a pathologically relevant event in human acute myeloid leukemia (AML) that contributes to impaired differentiation, enhanced self-renewal, and proliferation of immature myeloid cells. We demonstrate that ectopic expression of Snai1 in hematopoietic cells predisposes mice to AML development. This effect is mediated by interaction with the histone demethylase KDM1A/LSD1. Our data shed new light on the role of SNAI1 in leukemia development and identify a novel mechanism of LSD1 corruption in cancer. This is particularly pertinent given the current interest surrounding the use of LSD1 inhibitors in the treatment of multiple different malignancies, including AML.

Monosomy 3 Influences Epithelial-Mesenchymal Transition Gene Expression in Uveal Melanoma Patients; Consequences for Liquid Biopsy

Despite outstanding advances in diagnosis and the treatment of primary uveal melanoma (UM), nearly 50% of UM patients develop metastases via hematogenous dissemination, driven by the epithelial-mesenchymal transition (EMT). Despite the failure in UM to date, a liquid biopsy may offer a feasible non-invasive approach for monitoring metastatic disease progression and addressing protracted dormancy. To detect circulating tumor cells (CTCs) in UM patients, we evaluated the mRNA expression of EMT-associated transcription factors in CD45-depleted blood fraction, using qRT-PCR. ddPCR was employed to assess UM-specific GNA11, GNAQ, PLCβ4, and CYSLTR2 mutations in plasma DNA. Moreover, microarray analysis was performed on total RNA isolated from tumor tissues to estimate the prognostic value of EMT-associated gene expression. In total, 42 primary UM and 11 metastatic patients were enrolled. All CD45-depleted samples were negative for CTC when compared to the peripheral blood fraction of 60 healthy controls. Tumor-specific mutations were detected in the plasma of 21.4% patients, merely, in 9.4% of primary UM, while 54.5% in metastatic patients. Unsupervised hierarchical clustering of differentially expressed EMT genes showed significant differences between monosomy 3 and disomy 3 tumors. Newly identified genes can serve as non-invasive prognostic biomarkers that can support therapeutic decisions.

Knockdown of SAR1B suppresses proliferation and induces apoptosis of RKO colorectal cancer cells

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. SAR1 gene homolog B (SAR1B) is a GTPase that has been reported to have a central role in the regulation of lipid homeostasis and is associated with numerous diseases. However, its role in cancer, particularly in CRC, remains unclear. The present study revealed that SAR1B was overexpressed in CRC samples and this was associated with shorter overall survival time in patients with CRC. Colony formation, cell proliferation and flow cytometry assays were conducted to evaluate the functions of SAR1B in CRC. It was reported that SAR1B may be associated with tumorigenesis of CRC. Knockdown of SAR1B suppressed cell proliferation and induced significant apoptosis of RKO cells. Furthermore, microarray analysis was performed to identify the potential targets of SAR1B in CRC. Bioinformatics analysis revealed that SAR1B was significantly involved in regulating ‘TGF-β signaling’, ‘paxillin signaling’, ‘cell cycle regulation by BTG family proteins’ and ‘IGF-1 signaling’. These results suggested that SAR1B may be considered a potential prognostic biomarker and therapeutic target for CRC.

LY75 Ablation Mediates Mesenchymal-Epithelial Transition (MET) in Epithelial Ovarian Cancer (EOC) Cells Associated with DNA Methylation Alterations and Suppression of the Wnt/β-Catenin Pathway

Growing evidence demonstrates that epithelial-mesenchymal transition (EMT) plays an important role in epithelial ovarian cancer (EOC) progression and spreading; however, its molecular mechanisms remain poorly defined. We have previously shown that the antigen receptor LY75 can modulate EOC cell phenotype and metastatic potential, as LY75 depletion directed mesenchymal-epithelial transition (MET) in EOC cell lines with mesenchymal phenotype. We used the LY75-mediated modulation of EMT as a model to investigate for DNA methylation changes during EMT in EOC cells, by applying the reduced representation bisulfite sequencing (RRBS) methodology. Numerous genes have displayed EMT-related DNA methylation patterns alterations in their promoter/exon regions. Ten selected genes, whose DNA methylation alterations were further confirmed by alternative methods, were further identified, some of which could represent new EOC biomarkers/therapeutic targets. Moreover, our methylation data were strongly indicative for the predominant implication of the Wnt/β-catenin pathway in the EMT-induced DNA methylation variations in EOC cells. Consecutive experiments, including alterations in the Wnt/β-catenin pathway activity in EOC cells with a specific inhibitor and the identification of LY75-interacting partners by a proteomic approach, were strongly indicative for the direct implication of the LY75 receptor in modulating the Wnt/β-catenin signaling in EOC cells.

The prognostic significance of SHP2 and its binding protein Hook1 in non-small cell lung cancer

Background

We previously reported that Hook1 inhibits the phosphatase activity of SHP2 in the regulation of the epithelial-mesenchymal transition (EMT) in lung cancer. In this study, we performed a comprehensive analysis of SHP2 and Hook1 expression and relationships with the prognosis of patients with non-small cell lung cancer (NSCLC).

Materials and methods

A total of 121 patients with NSCLC were included in this study. Expression of SHP2 and Hook1 was assessed by immunohistochemistry and Western blot analysis. The overall survival rate of NSCLC patients was analysed using Cox’s ratio hazard multivariate analysis and the log-rank test.

Results

In tumour tissue specimens, positive expression rates of SHP2 proteins were 58.4% by immunohistochemical analysis. A significant correlation between expression of SHP2 and that of Hook1 was observed. Based on Western blot analysis, we found that Hook1 was downregulated and that SHP2 has a tendency to overexpress without statistical significance in NSCLC tissues compared with their levels in normal lung tissues. The median overall survival (OS) of NSCLC patients who presented low levels of SHP2 expression were better (40 vs 24 months, p=0.004) than those of patients who exhibited high levels of SHP2 expression. The results of multivariate analysis showed that the level of SHP2 expression was an independent prognostic factor for OS.

Conclusion

SHP2 might play an important role in NSCLC and has the potential to serve as a clinical biomarker or NSCLC.

Clinicopathological and prognostic significance of SHP2 and Hook1 expression in patients with thyroid carcinoma

Some thyroid carcinomas (TCs) have an aggressive biological behavior and poor prognosis, and lacking of effective molecular markers is still the main obstacle for clinical stratified diagnosis and treatment of TC. The aim of the study was to discover the clinicopathological and prognostic implications of Src homology region 2-containing protein tyrosine phosphatase 2 (SHP2) and Hook microtubule tethering protein 1 (Hook1) expression in TC. The expression of SHP2 and Hook1 was detected by immunohistochemistry on tissue microarrays from 313 primary TCs who underwent surgery in January 2006 and January 2010 in Zhejiang Cancer Hospital. The χ² test, Kaplan-Meier method, and Cox proportional-hazards regression models were used to analyze the associations between their expressions and clinicopathological features and prognosis. The expression rates of SHP2 and Hook1 in TC were 57.5% (180/313) and 22.0% (69/313), respectively. SHP2 was positively correlated with Hook1 in TC. SHP2 expression differed significantly by age, histologic variants, maximal tumor diameter, intrathyroidal dissemination, metastases, and disease stage (P < .05). Moreover, patients with high SHP2 expression had reduced risk for death of disease compared with those with low SHP2 expression (hazard ratio, 0.267; 95% confidence interval, 0.105-0.684; P = .006) in univariate analysis, but that multivariate analysis failed to suggest that SHP2 was an independent prognostic factor. Hook1 expression differed significantly by histologic variants, maximal tumor diameter, and intrathyroidal dissemination (P < .05). However, there was no significant correlation between Hook1 expression and outcome in TC (P > .05). Our results suggested that SHP2 may be a favorable indicator of prognosis in TC.

Quantitative proteomic analysis of pancreatic cyst fluid proteins associated with malignancy in intraductal papillary mucinous neoplasms

Background

The application of advanced imaging technologies for identifying pancreatic cysts has become widespread. However, accurately differentiating between low-grade dysplasia (LGD), high-grade dysplasia (HGD), and invasive intraductal papillary mucinous neoplasms (IPMNs) remains a diagnostic challenge with current biomarkers, necessitating the development of novel biomarkers that can distinguish IPMN malignancy.

Methods

Cyst fluid samples were collected from nine IPMN patients (3 LGD, 3 HGD, and 3 invasive IPMN) during their pancreatectomies. An integrated proteomics approach that combines filter-aided sample preparation, stage tip-based high-pH fractionation, and high-resolution MS was applied to acquire in-depth proteomic data of pancreatic cyst fluid and discover marker candidates for IPMN malignancy. Biological processes of differentially expressed proteins that are related to pancreatic cysts and aggressive malignancy were analyzed using bioinformatics tools such as gene ontology analysis and Ingenuity pathway analysis. In order to confirm the validity of the marker candidates, 19 cyst fluid samples were analyzed by western blot.

Results

A dataset of 2992 proteins was constructed from pancreatic cyst fluid samples. A subsequent analysis found 2963 identified proteins in individual samples, 2837 of which were quantifiable. Differentially expressed proteins between histological grades of IPMN were associated with pancreatic diseases and malignancy according to ingenuity pathway analysis. Eighteen biomarker candidates that were differentially expressed across IPMN histological grades were discovered—7 DEPs that were upregulated and 11 that were downregulated in more malignant grades. HOOK1 and PTPN6 were validated by western blot in an independent cohort, the results of which were consistent with our proteomic data.

Conclusions

This study demonstrates that novel biomarker candidates for IPMN malignancy can be discovered through proteomic analysis of pancreatic cyst fluid.

Electronic supplementary material

The online version of this article (10.1186/s12014-018-9193-1) contains supplementary material, which is available to authorized users.