TUSC3 accelerates cancer growth and induces epithelial-mesenchymal transition by upregulating claudin-1 in non-small-cell lung cancer cells

aCGH Analysis Reveals Novel Mutations Associated with Congenital Diaphragmatic Hernia Plus (CDH+)

Congenital diaphragmatic hernia (CDH) is a major birth anomaly that often occurs with additional non-hernia-related malformations, and is then referred to as CDH+. While the impact of genetic alterations does not play a major role in isolated CDH, patients with CDH+ display mutations that are usually determined via array-based comparative genomic hybridization (aCGH). We analyzed 43 patients with CDH+ between 2012 and 2021 to identify novel specific mutations via aCGH associated with CDH+ and its outcome. Deletions (n = 32) and duplications (n = 29) classified as either pathological or variants of unknown significance (VUS) could be detected. We determined a heterozygous deletion of approximately 3.75 Mb located at 8p23.1 involving several genes including GATA4, NEIL2, SOX7, and MSRA, which was consequently evaluated as pathological. Another heterozygous deletion within the region of 9p23 (9,972,017-10,034,230 kb) encompassing the Protein Tyrosine Phosphatase Receptor Type Delta gene (PTPRD) was identified in 2 patients. This work expands the knowledge of genetic alterations associated with CDH+ and proposes two novel candidate genes discovered via aCGH.

Downregulation of TUSC3 promotes EMT and hepatocellular carcinoma progression through LIPC/AKT axis

Background

Hepatocellular carcinoma (HCC) is one of the most common and malignant tumors in the digestive tract. Tumor Suppressor Candidate 3 (TUSC3) is one subunit of the endoplasmic reticulum Oligosaccharyl transferase (OST) complex, which plays an important role in N-glycosylation during the protein folding process. However, the role of TUSC3 in the initiation and progression of HCC has not been mentioned yet. In the present study, we aim to investigate the effects of TUSC3 on the initiation and progression of HCC.

Methods

Immunohistochemical assay and qRT-PCR were used to detect the expression of TUSC3 and lipase C hepatic type (LIPC) in HCC tissue and cells. Loss-of-function and gain-of-function were applied to detect the function of TUSC3 and LIPC in vivo and in vitro. Immunofluorescence assay and co-immunoprecipitation were used to detect the relationship between TUSC3 and LPC. Western blot was applied to detect the expression of epithelial–mesenchymal transition (EMT) markers and the Akt signaling pathway.

Results

TUSC3 was aberrantly decreased in hepatocellular carcinoma tissues compared to the matched adjacent normal tissues, which resulted in bigger size of tumor (P = 0.001, Table 2), worse differentiation (P = 0.006, Table 2) and an advanced BCLC stage. Down-regulation of TUSC3 led to the enhanced proliferation and migration of hepatocellular carcinoma cells in vivo and vitro, whereas the opposite effect could be observed in the TUSC3-overexpression group. The analysis of TUSC3 microarray showed that LIPC, a glycoprotein primarily synthesized and secreted by hepatocytes, was a downstream target of TUSC3, and it negatively modulated the development of HCC. The morphological changes in HCC cells indicated that TUSC3 regulated the epithelial-mesenchymal transition (EMT). Mechanistically, TUSC3 inhibited EMT progression through the LIPC/AKT axis.

Conclusion

Down-regulation of TUSC3 promotes EMT progression by activating AKT signaling via targeting LIPC in HCC, which is probably the possible mechanism driving TUSC3-deficient hepatocellular carcinoma cells toward a malignant phenotype.

TUSC3 induces drug resistance and cellular stemness via Hedgehog signaling pathway in colorectal cancer

Tumor suppressor candidate 3 (TUSC3) is a coding gene responsible for N-glycosylation of many critical proteins. TUSC3 gene plays an oncogenic role in colorectal cancer (CRC), however, the role of TUSC3 in drug resistance of CRC is still unclear. The aim of this study is to investigate the biological function and molecular mechanism of TUSC3 in CRC drug resistance. The expression of TUSC3 in CRC is positively correlated to tumor stage in 90 paired clinical samples, and negatively associated with overall survival and disease-free survival of CRC patients. In vitro, TUSC3 promotes the formation of stemness and induces the drug resistance to 5-fluorouracil and cis-dichlorodiammineplatinum(II) in CRC cells. The tissue microarray assay and bioinformatic analysis indicate that TUSC3 may promote the expression of CD133 and ABCC1 via Hedgehog signaling pathway. Treatment of Hedgehog signaling pathway agonist or inhibitor in TUSC3-silenced or TUSC3-overexpressed cells reverse the effects of TUSC3 in cellular stemness phenotype and drug resistance. Meanwhile, coimmunoprecipitation and immunofluorescence assays indicate a tight relationship between TUSC3 and SMO protein. Our data suggest that TUSC3 promotes the formation of cellular stemness and induces drug resistance via Hedgehog signaling pathway in CRC.

Aberrant expression of miR-4728 in patients with non-small cell lung cancer and its regulatory effects on tumor progression in tumor cells

Non-small cell lung cancer (NSCLC) is a common malignant tumor with poor prognosis and an increasing number of cases. MicroRNA (miR)-4728 is related with the progression of various types of cancer, and is dysregulated in NSCLC, which indicates that miR-4728 may serve as a biomarker for NSCLC. The present study aimed to investigate the clinical significance of miR-4728 in NSCLC diagnosis and prognosis, and to explore the biological function of miR-4728 in NSCLC progression. Serum and tissue samples were collected from 122 patients with NSCLC. By conducting reverse transcription-quantitative PCR, the Cell Counting Kit-8 assay and Transwell assays, the expression of miR-4728 and its effect on NSCLC cell proliferation, migration and invasion were investigated. The diagnostic value of miR-4728 was evaluated by plotting a receiver operating characteristic curve, and Kaplan-Meier and Cox regression analyses were conducted to assess the prognostic value of miR-4728. miR-4728 was significantly downregulated in NSCLC serum and tissue samples compared with healthy controls, with a relatively high diagnostic accuracy and ability to predict poor overall survival time in patients with NSCLC. By conducting gain- and loss-of-function experiments, the results indicated that miR-4728 knockdown significantly promoted NSCLC cell proliferation, migration and invasion compared with the inhibitor negative control (NC) group. By contrast, miR-4728 overexpression displayed the opposite effect on NSCLC cell proliferation, migration and invasion. The present study indicated that miR-4728 was downregulated in NSCLC and may serve as a candidate diagnostic and prognostic biomarker. NSCLC cell proliferation, migration and invasion were inhibited by miR-4728 overexpression compared with the mimic NC group, which suggested that miR-4728 may serve as a therapeutic target for NSCLC.

CircRNA hsa_circRNA_0000069 promotes the proliferation, migration and invasion of cervical cancer through miR-873-5p/TUSC3 axis

Background

Cervical cancer (CC) is the second leading cause of cancer deaths in women worldwide, still lacking effective biomarkers and therapies for diagnosis and treatment. CircRNAs are a class of endogenous RNAs that regulate gene expression through interacting with miRNAs, implicating in the progression of cancers. Yet the roles of circRNAs in CC are not fully characterized.

Methods

Fifty pairs of tumor and adjacent normal tissues from CC patients, as well as four CC cell lines and a normal human cervical epithelial cell line were subjected to qRT-PCR assay to assess the mRNA levels of hsa_circ_0000069. CCK-8 and colony formation assays were conducted to detect the proliferation of CC cells. Transwell assay was used to evaluate the migration and invasion capabilities of CC cells. RNA pull-down and luciferase assays were used to determine the interaction between hsa_circ_0000069 and miR-873-5p. A xenograft model of CC was established to verify the in vivo function of hsa_circ_0000069 in CC progression.

Results

We firstly demonstrated that hsa_circ_0000069 was significantly upregulated and closely related to the lymph node metastasis, and poor prognosis of CC patients. Besides, hsa_circ_0000069 promoted CC cell proliferation, migration, and invasion. The knockdown of hsa_circ_0000069 also inhibited CC tumor growth in vivo. Mechanically, we revealed that hsa_circ_0000069 functioned as an oncogene in CC, which is the sponge of miR-873-5p to facilitate the TUSC3 expression, consequently promoting CC progression.

Conclusion

We demonstrated a critical hsa_circ_0000069-miR-873-5p-TUSC3 function network involved in the CC progression, which provides mechanistic insights into the roles of CircRNAs in CC progression and a promising therapeutic target for CC treatment.

Tumour suppressor candidate 3 inhibits biological function and increases endoplasmic reticulum stress of melanoma cells WM451 by regulating AKT/GSK3-β/β-catenin pathway

Melanoma is a highly malignant and is a life-threatening disease with no effective treatment currently. This study aims to evaluate the significance of TUSC3, an endoplasmic reticulum stress (ERS)-inducible gene and explore its relationship with AKT/GSK3-β/β-catenin signalling pathway in melanoma cell WM451. We investigated TUSC3 expression in melanoma cell by qRT-PCR, CCK-8 and clonal formation assays were utilized to evaluate cell proliferation. Wound healing and transwell experiments detected cell migration and invasion. Flow cytometry detected the level of apoptosis. Western blot analysed MMP2, MMP9, p-AKT, p-GSK3-β, β-catenin and AKT, GSK3-β, ERS-related proteins and apoptosis-related proteins in WM451 cells. The results revealed that TUSC3 was remarkably decreased in melanoma cell lines. Overexpression of TUSC3 significantly inhibits melanoma cell WM451 biological functions and promotes expression of ERS-related proteins in WM451 cells, increases ERS in WM451 cells by inhibiting AKT/GSK3-β/β-catenin pathway. These finding suggest that TUSC3 regulates biological functions of melanoma cells WM451 and increases ERS in melanoma cells WM451 via the inhibition of the AKT/GSK3-β/β-catenin signalling pathway. SIGNIFICANCE OF THE STUDY: Melanoma is a highly malignant and is a life-threatening disease with no effective treatment currently. Therefore, studying the molecular mechanism of melanoma occurrence and metastasis is essential for the treatment of melanoma. Meanwhile, mounting studies suggest that TUSC3 is considered to be closely associated with the development of various malignancies. TUSC3 regulates proliferation, migration and epithelial-to-mesenchymal transition, but the molecular mechanism of the tumour suppressor effects of TUSC3 on melanoma cells is not well understood. Our study demonstrates that TUSC3 inhibits biological function of melanoma cells and increases ERS in melanoma cells by inhibiting AKT/GSK3-β/β-catenin pathway. And this is expected to be a new target and method for the treatment of melanoma.

Oligosaccharyltransferase: A Gatekeeper of Health and Tumor Progression

Oligosaccharyltransferase (OST) is a multi-span membrane protein complex that catalyzes the addition of glycans to selected Asn residues within nascent polypeptides in the lumen of the endoplasmic reticulum. This process, termed N-glycosylation, is a fundamental post-translational protein modification that is involved in the quality control, trafficking of proteins, signal transduction, and cell-to-cell communication. Given these crucial roles, N-glycosylation is essential for homeostasis at the systemic and cellular levels, and a deficiency in genes that encode for OST subunits often results in the development of complex genetic disorders. A growing body of evidence has also demonstrated that the expression of OST subunits is cell context-dependent and is frequently altered in malignant cells, thus contributing to tumor cell survival and proliferation. Importantly, a recently developed inhibitor of OST has revealed this enzyme as a potential target for the treatment of incurable drug-resistant tumors. This review summarizes our current knowledge regarding the functions of OST in the light of health and tumor progression, and discusses perspectives on the clinical relevance of inhibiting OST as a tumor treatment.

miR-873-5p inhibits the progression of colon cancer via repression of tumor suppressor candidate 3/AKT signaling

BACKGROUND AND AIM

We previously discovered that tumor suppressor candidate 3 (TUSC3) was overexpressed and predicted worse prognosis in colon cancer patients. However, the mechanisms of upregulation of TUSC3 in colon cancer remained unclear.

METHODS

MiR-873-5p was predicted and identified as the regulator of TUSC3 via online programs and luciferase reporter assays. The roles of miR-873-5p in regulating colon cancer cell proliferation, colony formation, and invasion were evaluated in vitro. Animal studies were performed to investigate the effects of miR-873-5p on proliferation and lung metastasis. Moreover, the miR-873-5p/TUSC3 related signaling pathway and the prognostic value of combining miR-873-5p and TUSC3 for colon cancer patients were also explored.

RESULTS

Here, we identified miR-873-5p as a novel regulator of TUSC3 in colon cancer. Functionally, ectopic expression or silencing of miR-873-5p, respectively, inhibited or promoted colon cancer cells proliferation, colony formation, and invasion, as well as prevented or enhanced the metastasis of colon cancer cells in vitro and in vivo. Molecularly, miR-873-5p functioned as a tumor suppressor by inhibiting the TUSC3/AKT pathway. Overexpression or silencing of TUSC3 could partially reverse the effects of the overexpression or repression of miR-873-5p on colon cancer progression caused by activation of the AKT pathway. Clinically, low miR-873-5p expression predicted poor survival in colon cancer patients, especially combined with high TUSC3 expression.

CONCLUSIONS

We identified miR-873-5p as a tumor suppressor, which acts by directly repressing TUSC3 in colon cancer.

TUSC3 as a potential biomarker for prognosis in clear cell renal cell carcinoma

The aim of the present study was to explore the expression levels of tumor suppressor candidate 3 (TUSC3) in human clear cell renal cell carcinoma (ccRCC) and its clinical value. Immunohistochemical staining, western blotting and reverse transcription-quantitative polymerase chain reaction were used to detect TUSC3 expression in paracancerous normal tissues and ccRCC tissues. The tissues were derived from the pathological specimens of 54 patients with ccRCC. Additionally, associations among TUSC3 expression and histological grade and clinicopathological staging of ccRCC were investigated. The results of these comparisons revealed that TUSC3 expression in ccRCC tissues was significantly lower than that in paracancerous tissues (P<0.05). TUSC3 expression in the high differentiation group was higher than that in the median and low differentiation groups (P<0.05). Expression levels of TUSC3 in stage I and II tissues were higher than those in stage III and IV tissues (P<0.05). The expression levels of TUSC3 in the lymph node metastasis group were lower than those in the non-lymph node metastasis group (P<0.05). In conclusion, the expression levels of TUSC3 in human ccRCC tissues were downregulated compared with those found in normal human renal tissue, and TUSC3 may inhibit the progression of ccRCC. Furthermore, the TUSC3 gene may be used as a promising tumor marker for the early diagnosis and prognosis of ccRCC.