High S phase kinase-associated protein 2 expression is a potential prognostic biomarker for glioma

Association of human telomerase reverse transcriptase promoter mutation with unfavorable prognosis in glioma: A systematic review and meta-analysis

Background

Glioma is one of the most malignant and aggressive tumors, with an extremely poor prognosis. Human telomerase reverse transcriptase (hTERT) promoter mutation is regarded as a risk factor in tumor growth. Although the prevalence of hTERT promoter (pTERT) mutation in gliomas has been investigated, the results are inconsistent. This meta-analysis aims to investigate the prognostic value of hTERT in glioma patients and its interaction with other biomarkers.

Materials and Methods

We searched 244 citations from four databases: PubMed (2000-2021), Web of Science (2000-2021), Embase (2010-2021), and Cochrane Library (2000-2021) with 28 articles included.

Results

We calculated hazard ratios (HRs) using the random effect model and the pooled result suggested that TERT promoter mutation predicted poorer overall survival (HR: 1.53, 95% confidence interval [CI]: 1.34-1.75, P < 0.001, I2: 49.9%, pheterogeneity:0.002) and progression-free survival (HR: 1.55, 95% CI: 1.27-1.88, P < 0.001, I2: 0.0%, pheterogeneity: 0.473). For subgroup analysis, we analyzed multiple factors including iso-citrate dehydrogenase (IDH) genotype, age, diagnosis, pTERT region, so as to locate the sources of heterogeneity. Interestingly, in IDH mutant subgroup, pTERT mutation became a beneficial prognostic factor (HR: 0.73, 95% CI: 0.57-0.93, I2: 22.3%, pheterogeneity: 0.277), which is contrary to the results in pooled analysis.

Conclusion

In general, pTERT mutation may result in shorter survival time in glioma patients, but longer survival time when glioma patients are combined with IDH mutation.

Gene S-phase kinase associated protein 2 is a novel prognostic marker in human neoplasms

BACKGROUND

Neoplasms are a series of diseases affecting human health. Prognostic and tumor status-related markers for various tumors should be identified.

METHODS

Based on 19,515 samples from multiple sources, for the first time, this study provided an overview of gene S-phase kinase associated protein 2 (SKP2) in pan-cancer. Differential SKP2 expression in multiple comparison groups was identified by the Kruskal-Wallis test and Wilcoxon rank-sum test. The prognosis significance of SKP2 in individuals with neoplasm was evaluated through univariate Cox regression analysis and Kaplan-Meier curves. The area under the curve was utilized to detect the accuracy of SKP2 in predicting cancer status. Spearman's rank correlation coefficients were calculated in all correlation analyses. Gene set enrichment analysis was used to identify essential signaling pathways of SKP2 in human neoplasms.

RESULTS

The study disclosed the upregulated SKP2 expression in 15 neoplasms and decreased SKP2 expression in three cancers (p < 0.05). The transcription factor Forkhead Box M1 may contribute to the increased expression levels of SKP2 in certain tumors. Over-expressed SKP2 represented a risk factor for the prognosis of most cancer patients (hazard ratio > 1, p < 0.05). SKP2 expression made it feasible to distinguish neoplasm and control tissues of 21 neoplasms (sensitivity = 0.79, specificity = 0.87, area under the curve = 0.90), implying its potential in screening a series of neoplasms. Further, the research revealed the close association of SKP2 expression with DNA methyltransferases, mismatch repair genes, microsatellite instability, tumor mutational burden, neoantigen count, and immunity.

CONCLUSIONS

SKP2 plays an essential role in multiple neoplasms and may serve as a marker for treating and identifying these neoplasms.

Overexpression of Podoplanin Predicts Poor Prognosis in Patients With Glioma

High podoplanin (PDPN) expression correlates with poor prognosis in various cancers. However, the expression and clinical value of PDPN in glioma are unclear. In this study, PDPN expression was compared in 227 glioma tissues and 22 paired non-neoplastic tissues, and its association with prognostic factors was statistically analyzed. The effect of PDPN knockdown on the proliferation ability of glioma cells (U87MG and U118MG cell lines) was assessed along with the underlying molecular mechanism. Overexpression of PDPN was observed in the majority of glioma tissues compared with the expression in normal tissues. PDPN overexpression was positively correlated with IDH wild-type status, TERT promoter mutation status, and ATRX retention status, and was negatively correlated with 1p/19q codeletion status. The expression level of PDPN was positively correlated with the glioma grade in the diffuse astrocytoma, IDH wild-type. High PDPN expression was also negatively correlated with survival in astrocytoma patients with IDH mutation or wild-type and in glioblastoma patients with IDH wild-type. Grade, radiochemotherapy, and PDPN overexpression emerged as independent indicators for a poor prognosis of glioma patients. PDPN knockdown suppressed proliferation and reduced p-Akt and p-mTOR protein expression in glioma cells. PDPN is a potential biomarker or therapeutic target for glioma that is closely associated with tumor grade and poor prognosis, which may play a role in enhancing cell proliferation via Akt/mTOR signaling.

Platycodin D suppresses proliferation, migration, and invasion of human glioblastoma cells through regulation of Skp2

BACKGROUND

Platycodin D (PD) is a major bioactive component of Platycodon grandiflorum, a medicinal herb that is widely used in China, and is effective against various human cancers, including glioblastoma multiforme (GBM). S phase kinase-related protein 2 (Skp2) is oncogenic and overexpressed in various human tumors. It is highly expressed in GBM and its expression is correlated with tumor growth, drug resistance and poor prognosis. In this study, we investigated whether inhibition of glioma progression by PD is mediated by decreasing expression of Skp2.

METHODS

Cell Counting Kit-8 (CCK-8) and Transwell assays were used to determine the effects of PD on GBM cell proliferation, migration, and invasion in vitro. mRNA and protein expression were determined by real time polymerase chain reaction (RT-PCR) and western blotting, respectively. The U87 xenograft model was used to verify the anti-glioma effect of PD in vivo. Expression levels of Skp2 protein were analyzed by immunofluorescence staining.

RESULTS

PD suppressed proliferation and motility of GBM cells in vitro. The expression of Skp2 in U87 and U251 cells was significantly reduced by PD. PD mainly decreased the cytoplasmic expression of Skp2 in glioma cells. Skp2 protein expression was downregulated by PD, resulting in upregulation of its downstream targets, p21and p27. The inhibitory effect of PD was enhanced by Skp2 knockdown in GBM cells and reversed in cells with Skp2 overexpression.

CONCLUSION

PD suppresses glioma development by regulation of Skp2 in GBM cells.

Clinical and genomic features in patients with second primary glioblastoma following first primary renal cell carcinoma

PURPOSE

To explore the potential pathogenesis and clinical features of second primary glioblastoma (spGBM) following first primary renal cell carcinoma (fpRCC).

METHODS

Patients with spGBM after fpRCC were enrolled from our institution and the SEER dataset. Sanger sequencing, whole genome sequencing, and immunehistochemistry were used to detect molecular biomarkers.

RESULTS

Four and 122 cases from our institution and the SEER dataset, respectively, were collected with an overall median age of 69 years at spGBM diagnosis following fpRCC. The median interval time between fpRCC and spGBM was 50.7 months and 4 years, for the four and 122 cases respectively. The median overall survival time was 11.2 and 6.0 months for the two datasets. In addition, spGBM patients of younger age (< 75 years) or shorter interval time (< 1 year) had favorable prognosis (p = 0.081 and 0.05, respectively). Moreover, the spGBM cases were molecularly classified as TERT only paired with TP53 mutation, PIK3CA mutation, EGFR alteration, low tumor mutation burden, and stable microsatellite status.

CONCLUSIONS

This is the first study to investigate the pathogenesis and clinical features of spGBM following spRCC. We found that spGBMs are old-age related, highly malignant, and have short survival time. Moreover, they might be misdiagnosed and treated as brain metastases from RCC. Thus, the incidence of spGBMs after fpRCC is underestimated. Further studies are needed to investigate the underlying molecular mechanisms and clinical biomarkers for the development of spGBM following fpRCC.

Echinacoside (ECH) suppresses proliferation, migration, and invasion of human glioblastoma cells by inhibiting Skp2-triggered epithelial-mesenchymal transition (EMT)

BACKGROUND

Echinacoside (ECH) is a phenylethanoid extracted from the stems of Cistanches salsa, an herb used in Chinese medicine formulations, and is effective against glioblastoma multiforme (GBM). Epithelial-mesenchymal transition (EMT) is the cornerstone of tumorigenesis and metastasis, and increases the malignant behavior of GBM cells. The S phase kinase-related protein 2 (skp2), an oncoprotein associated with EMT, is highly expressed in GBM and significantly associated with drug resistance, tumor grade and dismal prognosis. The aim of this study was to explore the inhibitory effects of ECH against GBM development and skp2-induced EMT.

METHODS

CCK-8, EdU incorporation, transwell, colony formation and sphere formation assays were used to determine the effects of ECH on GBM cell viability, proliferation, migration and invasion in vitro. The in vivo anti-glioma effects of ECH were examined using a U87 xenograft model. The expression levels of skp2 protein, EMT-associated markers (vimentin and snail) and stemness markers (Nestin and sox2) were analyzed by immunohistochemistry, immunofluorescence staining and western blotting experiments.

RESULTS

ECH suppressed the proliferation, invasiveness and migration of GBM cells in vitro, as well as the growth of U87 xenograft in vivo. In addition, ECH downregulated the skp2 protein, EMT-related markers (vimentin and snail) and stemness markers (sox2 and Nestin). The inhibitory effects of ECH were augmented in the skp2-knockdown GBM cells, and reversed in cells with ectopic expression of skp2.

CONCLUSION

ECH inhibits glioma development by suppressing skp2-induced EMT of GBM cells.