Differential expression of p42.3 in low- and high-grade gliomas

Comprehensive Bioinformatics Analyses and Experimental Validation of the Cell Cycle Related Protein SAPCD2 as a New Biomarker and Potential Therapeutic Target in Pancreatic Cancer

Purpose

Pancreatic adenocarcinoma (PAAD) is a highly aggressive cancer with a poor prognosis, reliable markers are urgently needed for early detection and prognosis evaluation. SAPCD2, a cell cycle related gene, has been implicated in tumorigenesis and proposed as a potential therapeutic target in cancer. However, no comprehensive study has explored its expression and regulation, discussed its role in tumor prognosis and immune modulation, along with therapy response in pan-cancer until now.

Methods

SAPCD2 expression was analyzed using data from The Cancer Genome Atlas database (TCGA) and Human Protein Atlas (HPA) database. Genetic and epigenetic alterations of SAPCD2 and the immune microenvironment were explored via NCBI, TIMER2 and cBioPortal platforms. Western blot analysis and immunohistochemistry (IHC) were performed to check SAPCD2 protein expression in PAAD cells and tissues. Cell counting kit 8 (CCK8), flow cytometry, and transwell experiments were used to evaluate the role of SAPCD2 in PAAD cell lines.

Results

Our study found that SAPCD2 is notably upregulated in various cancers, especially early-stage digestive cancers, and is linked to poor survival in most cancers like PAAD and LIHC. Gene amplification and promoter DNA hypomethylation appear to drive this upregulation. Additionally, SAPCD2 expression correlates with tumor mutation burden, microsatellite instability, and immune scores across several cancers. In PAAD, elevated SAPCD2 levels correlated with reduced immune activity, whereas in stomach cancer (STAD), its prognostic impact appeared immune-independent. In PDAC cell lines, SAPCD2 knockdown reduced proliferation and invasion, and caused reduction of G0/G1 phase. PAAD cells with high SAPCD2 expression showed increased sensitivity to DNA-PK, p38α MAPK, and Bcl-2 inhibitors.

Conclusion

SAPCD2 serves as both a prognostic marker and a potential therapeutic target in PAAD, where its low expression may enhance responsiveness to specific drugs. These findings underscore SAPCD2's dual role in cancer progression and therapy.

Prognostic value of RNA methylation-related genes in gastric adenocarcinoma based on bioinformatics

Background

Gastric cancer (GC) is a malignant tumor that originates from the epithelium of the gastric mucosa and has a poor prognosis. Stomach adenocarcinoma (STAD) covers 95% of total gastric cancer. This study aimed to identify the prognostic value of RNA methylation-related genes in gastric cancer.

Methods

In this study, The Cancer Genome Atlas (TCGA)-STAD and GSE84426 cohorts were downloaded from public databases. Patients were classified by consistent cluster analysis based on prognosis-related differentially expressed RNA methylation genes Prognostic genes were obtained by differential expression, univariate Cox and least absolute shrinkage and selection operator (LASSO) analyses. The prognostic model was established and validated in the training set, test set and validation set respectively. Independent prognostic analysis was implemented. Finally, the expression of prognostic genes was affirmed by reverse transcription quantitative PCR (RT-qPCR).

Results

In total, four prognostic genes (ACTA2, SAPCD2, PDK4 and APOD) related to RNA methylation were identified and enrolled into the risk signature. The STAD patients were divided into high- and low-risk groups based on the medium value of the risk score, and patients in the high-risk group had a poor prognosis. In addition, the RNA methylation-relevant risk signature was validated in the test and validation sets, and was authenticated as a reliable independent prognostic predictor. The nomogram was constructed based on the independent predictors to predict the 1/3/5-year survival probability of STAD patients. The gene set enrichment analysis (GSEA) result suggested that the poor prognosis in the high-risk subgroup may be related to immune-related pathways. Finally, the experimental results indicated that the expression trends of RNA methylation-relevant prognostic genes in gastric cancer cells were in agreement with the result of bioinformatics.

Conclusion

Our study established a novel RNA methylation-related risk signature for STAD, which was of considerable significance for improving prognosis of STAD patients and offering theoretical support for clinical therapy.

The Function and Regulation of SAPCD2 in Physiological and Oncogenic Processes

The Suppressor APC Domain Containing 2 (SAPCD2) gene, also known by its aliases p42.3 and c9orf140, encodes a protein with an approximate molecular weight of 42.3 kDa. It was initially recognized as a cell cycle-associated protein involved in mitotic progression. Since the initial discovery of this gene, emerging evidence has suggested that its functions extend beyond that of regulating cell cycle progression to include modulation of planar polarization of cell progenitors and determination of cell fate throughout embryonic development. The underlying mechanisms driving such functions have been partially elucidated. However, the detailed mechanisms of action remain to be further characterized. The expression level of SAPCD2 is high throughout embryogenesis but is generally absent in healthy postnatal tissues, with restored expression in adult tissues being associated with various disease states. The pathological consequences of its aberrant expression have been investigated, most notably in the development of several types of cancers. The role of SAPCD2 in tumorigenesis has been supported by in vitro, in vivo, and retrospective clinical investigations and the mechanisms underlying its oncogenic function have been partially revealed. The potential of SAPCD2 as a diagnostic marker and therapeutic target of cancers have also been explored and have shown great promise. However, many questions pertaining to its oncogenic mechanisms as well as its value as a diagnostic marker and therapeutic target remain to be answered. In addition to its function as an oncogene, an involvement of SAPCD2 in other pathological processes such as inflammation has also been implicated and provides additional directions that warrant future investigation. This article reviews the current understanding of the normal cellular functions of SAPCD2 and the relevance of SAPCD2 in disease development with a primary focus on tumorigenesis. The mechanisms that regulate p43.2 expression, including the potential role of microRNAs in regulating its expression, are also reviewed. To the best of our knowledge, we are the first to comprehensively review the published findings regarding the physiological and pathological functions of this gene.

Silencing SAPCD2 Represses Proliferation and Lung Metastasis of Fibrosarcoma by Activating Hippo Signaling Pathway

The primary problem associated with fibrosarcoma is its high potential to metastasize to the lung. Aberrant expression of SAPCD2 has been widely reported to be implicated in the progression and metastasis in multiple cancer types. However, the clinical significance and biological roles of SAPCD2 in fibrosarcoma remain unknown. Here, we reported that SAPCD2 expression was markedly elevated in fibrosarcoma tissues, and its expression was differentially upregulated in fibrosarcoma cell lines compared with that in several primary fibroblast cell lines. Kaplan-Meier survival analysis revealed that SAPCD2 overexpression was significantly correlated with early progression and metastasis, and poor prognosis in fibrosarcoma patients. Our results further showed that silencing SAPCD2 inhibited the proliferation and increased the apoptosis of fibrosarcoma cells in vitro. Importantly, silencing SAPCD2 repressed lung metastasis of fibrosarcoma cells in vivo. Mechanistic investigation further demonstrated that silencing SAPCD2 inhibited the proliferation and lung metastasis of fibrosarcoma cells by activating the Hippo signaling pathway, as evidenced by the finding that constitutively active YAP1, YAP1-S127A, significantly reversed the inhibitory effect of SAPCD2 downregulation on the colony formation and anchorage-independent growth capabilities of fibrosarcoma cells, as well as the stimulatory effect on the apoptotic ratio of fibrosarcoma cells. In conclusion, SAPCD2 promotes the proliferation and lung metastasis of fibrosarcoma cells by regulating the activity of Hippo signaling, and this mechanism represents a potential therapeutic target for the treatment of lung metastatic fibrosarcoma.

Expression of p42.3 in non-small cell lung cancer

Background

Lung cancer is the most malignant tumor with the highest morbidity and mortality. This study aimed to investigate the role of the expression and the significance of the p42.3 gene in non-small cell lung cancer (NSCLC).

Methods

Lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) were analyzed based on the biological information data of The Cancer Genome Atlas (TCGA). Furthermore, 142 postoperative tumor tissue and normal tissue samples (70 cases of LUAD and 72 cases of LUSC) from NSCLC patients admitted to our hospital from 2005 to 2009 were retrospectively collected. Paraffin-embedded tissues were used to make the tissue microarrays (TMA), and the expression of the p42.3 protein was detected by immunohistochemical staining.

Results

The expression of p42.3 in both LUAD and LUSC was significantly upregulated (P<0.01) compared with the normal lung tissues. The p42.3 expression was significantly higher than that of LUAD (P<0.01) in the LUSC group. LUSC had a lower level of p42.3 DNA methylation and a higher level of p42.3 DNA amplification than LUAD. The expression rate of p42.3 protein decreased in patients 70 years or older (P=0.029). High expression of the p42.3 protein was an independent factor for worse pathological differentiation (P=0.043).

Conclusions

Both genetic and epigenetic alterations contributed to dysregulated p42.3 in NSCLC. Despite the temporary absence of TCGA-LUSC (TCGA data on LUSC) survival information, we observed that the up-regulated expression of p42.3 in LUSC was significantly higher than that in LUAD by analyzing the public database and reviewing the real-world data. Furthermore, a high expression of p42.3 protein was significantly correlated with poor differentiation of tumor tissues. Therefore, the prognostic value of p42.3 in LUSC deserves further study.

Overexpression of SAPCD2 correlates with proliferation and invasion of colorectal carcinoma cells

Background

Suppressor anaphase-promoting complex domain containing 2 (SAPCD2) is a novel gene playing important roles in the initiation, invasion, and metastasis of several malignancies. However, its role in colorectal carcinoma (CRC) still remains unclear.

Method

In this study, we investigated the expression and biological function of SAPCD2 in CRC. Immunohistochemistry (IHC) for SAPCD2 was performed in 410 pairs of CRC specimens and corresponding normal epithelial tissues, and in 50 adenoma tissues. Clinical pathological factors were analyzed in relation to the expression of SAPCD2. The biological functions of SAPCD2 in CRC cells and its effect on cell cycle were investigated in vitro and in vivo through gain/loss-of-function approaches.

Results

IHC showed that SAPCD2 expression was significantly higher in CRC tissues compared to adenoma and normal epithelium tissues and was correlated with tumor location (p = 0.018). SAPCD2 significantly promoted cell proliferation, migration, and invasion both in vitro and in vivo (p < 0.05). In addition, SAPCD2 knockdown in CRC cells was associated with reduced G₁/S transition, while overexpression caused G₂/M phase arrest (p < 0.05).

Conclusions

In sum, SAPCD2 is overexpressed in CRC tissues and plays a critical role in CRC progression. Therefore, it might represent a promising therapeutic target for CRC treatment.

Overexpression of p42.3 promotes cell proliferation, migration, and invasion in human gastric cancer cells

As a newly discovered tumor-specific gene, p42.3 is overexpressed in most of human gastric cancers (GC). However, the role of p42.3 in GC progression remains unclear. To assess the role of p42.3 in gastric cancers, immunohistochemistry and western blot were performed to detect the p42.3 expression in human GC tissues and cells. We also investigated the role of p42.3 in GC cell proliferation, migration, and invasion. Our results showed that the p42.3 expression was increased dramatically in human GC tissue and cells. In addition, we found that overexpression of p42.3 promotes GC cell proliferation, migration, and invasion abilities. Furthermore, p42.3 expression suppressed the E-cadherin protein level and promoted the β-catenin and p-ERK protein level. Taken together, overexpressed p42.3 is correlated with gastric cancer cell proliferation, migration, and invasion, suggesting its use as a biological marker in gastric cancer.

RNaseH2A is involved in human gliomagenesis through the regulation of cell proliferation and apoptosis

Mutations in the RNaseH2A gene are involved in Aicardi‑Goutieres syndrome, an autosomal recessive neurological dysfunction; however, studies assessing RNaseH2A in relation to glioma are scarce. This study aimed to assess the role of RNaseH2A in glioma and to unveil the underlying mechanisms. RNaseH2A was silenced in glioblastoma cell lines U87 and U251. Gene expression was assessed in the cells transfected with RNaseH2A shRNA or scramble shRNA by microarrays, validated by quantitative real time PCR. Protein expression was evaluated by western blot analysis. Cell proliferation was assessed by the MTT assay; cell cycle distribution and apoptosis were analyzed by flow cytometry. Finally, the effects of RNaseH2A on colony formation and tumorigenicity were assessed in vitro and in a mouse xenograft model, respectively. RNaseH2A was successively knocked down in U87 and U251 cells. Notably, RNaseH2A silencing resulted in impaired cell proliferation, with 70.7 and 57.8% reduction in the U87 and U251 cells, respectively, with the cell cycle being blocked in the G0/G1 phase in vitro. Meanwhile, clone formation was significantly reduced by RNaseH2A knockdown, which also increased cell apoptosis by approximately 4.5-fold. In nude mice, tumor size was significantly decreased after RNaseH2A knockdown: 219.29±246.43 vs. 1160.26±222.61 mm3 for the control group; similar findings were obtained for tumor weight (0.261±0.245 and 1.127±0.232 g) in the shRNA and control groups, respectively). In the microarray data, RNaseH2A was shown to modulate several signaling pathways responsible for cell proliferation and apoptosis, such as IL-6 and FAS pathways. RNaseH2A may be involved in human gliomagenesis, likely by regulating signaling pathways responsible for cell proliferation and apoptosis.