Clinical significance of SLP-2 in hepatocellular carcinoma tissues and its regulation in cancer cell proliferation, migration, and EMT

Stomatin‑like protein 2 induces metastasis by regulating the expression of a rate‑limiting enzyme of the hexosamine biosynthetic pathway in pancreatic cancer

Stomatin-like protein 2 (SLP-2) is associated with poor prognosis in several types of cancer, including pancreatic cancer (PC); however, the molecular mechanism of its involvement remains elusive. The present study aimed to elucidate the role of this protein in the development of PC. Human PC cell lines AsPC-1 and PANC-1 were transfected by a vector expressing SLP-2 shRNA. Analyses of cell proliferation, migration, invasion, chemosensitivity, and glucose uptake were conducted, while a mouse xenograft model was used to evaluate the functional role of SLP-2 in PC. Immunohistochemical analysis was retrospectively performed on human tissue samples to compare expression between the primary site (n=279) and the liver metastatic site (n=22). Furthermore, microarray analysis was conducted to identify the genes correlated with SLP-2. In vitro analysis demonstrated that cells in which SLP-2 was suppressed exhibited reduced cell motility and glucose uptake, while in vivo analysis revealed a marked decrease in the number of liver metastases. Immunohistochemistry revealed that SLP-2 was increased in liver metastatic sites. Microarray analysis indicated that this protein regulated the expression of glutamine-fructose-6-phosphate transaminase 2 (GFPT2), a rate-limiting enzyme of the hexosamine biosynthesis pathway. SLP-2 contributed to the malignant character of PC by inducing liver metastasis. Cell motility and glucose uptake may be induced via the hexosamine biosynthesis pathway through the expression of GFPT2. The present study revealed a new mechanism of liver metastasis and indicated that SLP-2 and its downstream pathway could provide novel therapeutic targets for PC.

Stomatin-like protein 2 (SLP2) regulates the proliferation and invasion of trophoblast cells by modulating mitochondrial functions

INTRODUCTION

Stomatin-like protein 2 (SLP2) is highly expressed in human first trimester trophoblast cells, but its functions in placental morpho-physiology remain unknown. This study aimed to determine the role of SLP2 in the proliferation and invasion of human first trimester trophoblast cells.

METHODS

Immunofluorescence was used to determine the expression and localization of SLP2 in normal and miscarriage human first trimester placenta. Western blot was used to determine the expression of SLP2, PCNA, Cyclin D3, N-cadherin, Vimentin, PGC1α and PPARα in HTR-8/SVneo cells. SLP2 was knocked down in the HTR-8/SVneo cells by using si-Slp2. Wound healing and migration assays were used to determine the effect of SLP2 knockdown on the migration and invasion in the HTR-8/SVneo cells. Mitochondrial membrane potential, reactive oxygen species (ROS), ATP production and biogenesis were measured to assess the effects of SLP2 knockdown on mitochondrial functions.

RESULT

SLP2 was strongly expressed in the cytotrophoblasts (CTB), syncytiotrophoblast (STB) and extravillous trophoblasts (EVT) of normal pregnancy placenta as compared to miscarriage placenta. SLP2 was highly expressed in the invasive EVT cell lines, HTR-8/SVneo and HPT-8 compared to the CTB cell line JAR. Knockdown of SLP2 significantly inhibited the migration and invasion of HTR-8/SVneo cells and placental villous explants, and repressed mitochondrial biogenesis and functions in HTR-8/SVneo cells.

DISCUSSION

Silencing of SLP2 inhibited the proliferation, migration and invasion of HTR-8/SVneo cells via the impairment of mitochondrial functions. This indicates that the downregulation of SLP2 in miscarriage placenta could be part of the pathogenesis and pathophysiology of the disease.

Effect of CELSR3 on the Cell Cycle and Apoptosis of Hepatocellular Carcinoma Cells

Cadherin EGF LAG seven-pass G-type receptor 3 (CELSR3) has been reported in cancers but its role and potential molecular mechanism in hepatocellular carcinoma (HCC) is unclear. Therefore, we aimed to investigate the clinical value and molecular mechanism of CELSR3 in HCC using an in vitro experiment, a meta-analysis and bioinformatics. The in vitro experiment determined the promoting effect of CELSR3 in the proliferation, invasion, and migration of HCC cells. CELSR3 knockout causes S-phage arrest in HCC cells. CELSR3 can also inhibit the apoptosis of HCC cells. The expression of the CELSR3 gene and protein was significantly elevated in HCC. Elevated CELSR3 was correlated to the bigger tumor size, higher pathological stage, and the worse overall survival of HCC. Methylation analysis revealed that the hypomethylation of CELSR3 regulated by DNMT1, DNMT3A, and DNMT3B may be the underlying mechanism of upregulated CELSR3. Biological enrichment analysis uncovered that the cell cycle, DNA replication, and PI3K-Akt signaling pathways were important pathways regulated by CELSR3 and its co-expressed genes in HCC. Taken together, upregulated CELSR3 is an important regulator in the progression and prognosis of HCC. The hypomethylation of CELSR3 and its regulation in the cell cycle may be the potential molecular mechanism in HCC.

SOX5 promotes cell invasion and metastasis via activation of Twist-mediated epithelial-mesenchymal transition in gastric cancer

Background

Sex-determining region Y-box protein 5 (SOX5) has been demonstrated to be implicated in oncogenic function in various types of cancers. However, the role of SOX5 in gastric cancer (GC) remains poorly elucidated. Herein, we investigated the role and the underlying mechanism of SOX5 in GC progression.

Methods

SOX5 mRNA and protein expression were detected by quantitative real-time PCR (qRT-PCR), Western blot and immunohistochemistry in human GC specimens, and their clinical significance was evaluated. The effects of SOX5 knockdown or overexpression on GC cell behavior were determined by proliferation, wound-healing and transwell assays in vitro, and metastasis assays in vivo; and epithelial-mesenchymal transition (EMT)-related markers were detected by qRT-PCR, Western blot and immunofluorescence staining.

Results

The up-regulated expression of SOX5 in GC specimens was significantly correlated with clinical metastasis and poor prognosis for patients with GC. Besides, SOX5 promoted GC cell migration and invasion in vitro, as well as GC cell metastasis in vivo. Mechanically, Twist-mediated EMT was likely involved in SOX5-facilitated GC cell behavior.

Conclusion

SOX5 has an important function in GC progression. In addition, SOX5 promotes GC cell invasion and metastasis via activation of Twist-mediated EMT, thus providing a potential therapeutic target for GC metastasis.

Expression and clinical significance of SLP-2 in ovarian tumors

The expression and clinical significance of stomatin-like protein 2 (SLP-2) in ovarian tumors were investigated. A total of 280 cases of ovarian tissue specimens preserved from inpatients after surgical treatments in the Department of Oncology of Yidu Central Hospital of Weifang from April 2013 to May 2016 were collected, including 130 cases of malignant ovarian tumor tissue specimens (malignant tumor group), 75 cases of benign ovarian tumor tissue specimens (benign tumor group) and 75 cases of normal ovarian tissue specimens from bilateral ovariectomy for unilateral ovarian lesions (control group). Immunohistochemistry was used to detect the expression of SLP-2 protein in the three groups. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was utilized to detect the relative expression of SLP-2 mRNA in the three groups, and the relationship between SLP-2 and clinicopathological parameters of the ovarian cancer patients was analyzed. The patients with ovarian cancer were divided into the SLP-2 high-expression group and the SLP-2 low-expression group according to the median of SLP-2 relative expression. The survival of patients was analyzed using the Kaplan-Meier and Cox regression model. The results of immunohistochemistry showed that the positive expression rate of SLP-2 protein in the malignant tumor group was significantly higher than that in the benign tumor and control groups (P<0.001). The results of RT-qPCR showed that compared with the control group, the relative expression of SLP-2 mRNA in the ovarian tissues in the benign tumor group and the malignant tumor group was increased (P<0.001). The relative expression of SLP-2 mRNA in the malignant tumor group was higher than that in the benign tumor group (P<0.001). The relative expression of SLP-2 mRNA correlated with clinical stage, pathological differentiation and lymph node metastasis of the patients with ovarian cancer (P<0.05). The 5-year overall survival (OS) in the SLP-2 mRNA high expression group was significantly lower than that in the SLP-2 mRNA low expression group at 5 years (P<0.05). SLP-2 mRNA was an independent prognostic factor influencing OS of the patients (P<0.05). SLP-2 may be involved in the occurrence and development of ovarian cancer and related to the clinical stage, pathological differentiation and lymph node metastasis of the patients with ovarian cancer, which may also play a role in promoting the invasion and metastasis processes of ovarian cancer. Therefore, SLP-2 is expected to be an effective biomarker for targeted treatment and prognosis of ovarian tumor.

Enhanced SLP-2 promotes invasion and metastasis by regulating Wnt/β-catenin signal pathway in colorectal cancer and predicts poor prognosis

Stomatin-like protein-2 (SLP-2) gene belongs to the stomatin supergene family, and previous studies have revealed up-regulated SLP-2 expression in gallbladder cancer, lung cancer, and esophageal cancer, while the role of SLP-2 in colorectal cancer (CRC) remains unclear and needs further investigation. Therefore, the expression levels of SLP-2 in CRC tissue and cell lines were tested in this study. Besides, we further explored the role of SLP-2 in CRC invasion and metastasis at molecular level via gene intervention technique. Our results demonstrated that the positive rate of SLP-2 expression in CRC tissues was higher than that in the adjacent non-cancerous tissues (P < 0.05); positive SLP-2 expression predicted poorer prognosis of CRC patients as an independent risk factor (P < 0.05). Cell activities and the capacity of migration and invasion significantly decreased after the suppression of SLP-2 in SW620 cells (P < 0.05). Furthermore, the suppression of SLP-2 in SW620 cells resulted in varieties of invasion and metastasis-related genes and Wnt/β-catenin signal pathway (P < 0.05). The present study identified that SLP-2 may predict a poor prognosis in CRC patients as a novel marker, and SLP-2 may facilitate the migration and invasion of CRC via regulating Wnt/β-catenin pathway activities.

[Silencing of SLP-2 inhibits the migration and invasion of cervical cancer cells in vitro]

OBJECTIVE

To investigate the effect of SLP-2 silencing on the migration and invasion of human cervical cancer cells and explore the mechanism.

METHODS

Small interfering RNA (siRNA) was used to knockdown the expression of SLP-2 in Hela cells and Siha cells. At 48 h after the transfection, the cells were examined for SLP-2 expression with Western blotting, and wound healing assay and Transwell assay were used to evaluate the changes in the cell migration; Matrigel Transwell assay was used to evaluate the changes in the invasion ability of the cells. The expressions of E-cadherin, β-catenin, vimentin and Twist in Hela and Siha cells following the transfection were detected with Western blotting.

RESULTS

Compared with the control cells, siRNA transfection significantly lowered the expression of SLP-2 and suppressed the migration and invasion ability of Hela cells and Siha cells (P < 0.01). Silencing SLP-2 induced obvious up-regulation of epithelial cell phenotype proteins E-cadherin and β-catenin, down- regulated the expression of interstitial cell phenotype protein vimentin, and lowered the expression of Twist in the cells.

CONCLUSIONS

Silencing SLP-2 via siRNA transfection can inhibit epithelial-mesenchymal transition of human cervical cancer cells and lower their migration and invasion abilities possibly in relation with downregulated expression of Twist.