Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor and refractory to existing therapies. The oncogene BMI-1, a member of Polycomb Repressive Complex 1 (PRC1) plays essential roles in various human cancers and becomes an attractive therapeutic target. Here we showed that BMI-1 is highly expressed in GBM and especially enriched in glioblastoma stem cells (GSCs). Then we comprehensively investigated the anti-GBM effects of PTC-209, a novel specific inhibitor of BMI-1. We found that PTC-209 efficiently downregulates BMI-1 expression and the histone H2AK119ub1 levels at microM concentrations. In vitro, PTC-209 effectively inhibits glioblastoma cell proliferation and migration, and GSC self-renewal. Transcriptomic analyses of TCGA datasets of glioblastoma and PTC-209-treated GBM cells demonstrate that PTC-209 reverses the altered transcriptional program associated with BMI-1 overexpression. And Chromatin Immunoprecipitation assay confirms that the derepressed tumor suppressor genes belong to BMI-1 targets and the enrichment levels of H2AK119ub1 at their promoters is decreased upon PTC-209 treatment. Strikingly, the glioblastoma growth is significantly attenuated by PTC-209 in a murine orthotopic xenograft model. Therefore our study provides proof-of-concept for inhibitors targeting BMI-1 in potential applications as an anti-GBM therapy.

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor and refractory to existing therapies. The oncogene BMI-1, a member of Polycomb Repressive Complex 1 (PRC1) plays essential roles in various human cancers and becomes an attractive therapeutic target. Here we showed that BMI-1 is highly expressed in GBM and especially enriched in glioblastoma stem cells (GSCs). Then we comprehensively investigated the anti-GBM effects of PTC-209, a novel specific inhibitor of BMI-1. We found that PTC-209 efficiently downregulates BMI-1 expression and the histone H2AK119ub1 levels at microM concentrations. In vitro, PTC-209 effectively inhibits glioblastoma cell proliferation and migration, and GSC self-renewal. Transcriptomic analyses of TCGA datasets of glioblastoma and PTC-209-treated GBM cells demonstrate that PTC-209 reverses the altered transcriptional program associated with BMI-1 overexpression. And Chromatin Immunoprecipitation assay confirms that the derepressed tumor suppressor genes belong to BMI-1 targets and the enrichment levels of H2AK119ub1 at their promoters is decreased upon PTC-209 treatment. Strikingly, the glioblastoma growth is significantly attenuated by PTC-209 in a murine orthotopic xenograft model. Therefore our study provides proof-of-concept for inhibitors targeting BMI-1 in potential applications as an anti-GBM therapy.

Summary Background: Biomarkers for esophageal squamous cell carcinoma (ESCC) identification with high sensitivity are not well established. Since abnormal expression of cadherins has been widely reported in cancer, we explored its feasibility as an ESCC biomarker. Methods: Expression of E-cadherin and N-cadherin were detected in 150 esophageal tissues by immunohistochemistry. Staining strength and percentage in different subcellular structures of each specimen were evaluated by 2 independent pathologists. A logistic regression-based classifier derived from E-cadherin and N-cadherin staining was generated. Results: E-cadherin exhibited decreased membrane expression in ESCC, while N-cadherin exhibited decreased expression in the nucleus but elevated expression in the cytoplasm. Both E-cadherin and N-cadherin could distinguish ESCC tissues from non-cancerous tissues (area under the curve (AUC) = 0.748, 0.801, respectively). E-cadherin and N-cadherin staining scores could be merged into a cadherin (CDH) logistic index, which showed better discrimination (AUC = 0.909) than E-cadherin or N-cadherin alone. Further investigation indicated that the CDH logistic index was significantly correlated with tumor size and differentiation in ESCC. Conclusion: Both E-cadherin and N-cadherin had a strong expression shift in ESCC compared with non-cancerous tissues. The CDH logistic index, a parameter integrating the expression data of both cadherins, could be used as a marker with high sensitivity and specificity in the identification of ESCC.

Summary Background: Biomarkers for esophageal squamous cell carcinoma (ESCC) identification with high sensitivity are not well established. Since abnormal expression of cadherins has been widely reported in cancer, we explored its feasibility as an ESCC biomarker. Methods: Expression of E-cadherin and N-cadherin were detected in 150 esophageal tissues by immunohistochemistry. Staining strength and percentage in different subcellular structures of each specimen were evaluated by 2 independent pathologists. A logistic regression-based classifier derived from E-cadherin and N-cadherin staining was generated. Results: E-cadherin exhibited decreased membrane expression in ESCC, while N-cadherin exhibited decreased expression in the nucleus but elevated expression in the cytoplasm. Both E-cadherin and N-cadherin could distinguish ESCC tissues from non-cancerous tissues (area under the curve (AUC) = 0.748, 0.801, respectively). E-cadherin and N-cadherin staining scores could be merged into a cadherin (CDH) logistic index, which showed better discrimination (AUC = 0.909) than E-cadherin or N-cadherin alone. Further investigation indicated that the CDH logistic index was significantly correlated with tumor size and differentiation in ESCC. Conclusion: Both E-cadherin and N-cadherin had a strong expression shift in ESCC compared with non-cancerous tissues. The CDH logistic index, a parameter integrating the expression data of both cadherins, could be used as a marker with high sensitivity and specificity in the identification of ESCC.

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor and refractory to existing therapies. The oncogene BMI-1, a member of Polycomb Repressive Complex 1 (PRC1) plays essential roles in various human cancers and becomes an attractive therapeutic target. Here we showed that BMI-1 is highly expressed in GBM and especially enriched in glioblastoma stem cells (GSCs). Then we comprehensively investigated the anti-GBM effects of PTC-209, a novel specific inhibitor of BMI-1. We found that PTC-209 efficiently downregulates BMI-1 expression and the histone H2AK119ub1 levels at microM concentrations. In vitro, PTC-209 effectively inhibits glioblastoma cell proliferation and migration, and GSC self-renewal. Transcriptomic analyses of TCGA datasets of glioblastoma and PTC-209-treated GBM cells demonstrate that PTC-209 reverses the altered transcriptional program associated with BMI-1 overexpression. And Chromatin Immunoprecipitation assay confirms that the derepressed tumor suppressor genes belong to BMI-1 targets and the enrichment levels of H2AK119ub1 at their promoters is decreased upon PTC-209 treatment. Strikingly, the glioblastoma growth is significantly attenuated by PTC-209 in a murine orthotopic xenograft model. Therefore our study provides proof-of-concept for inhibitors targeting BMI-1 in potential applications as an anti-GBM therapy.