EBF1-Mediated Upregulation of Ribosome Assembly Factor PNO1 Contributes to Cancer Progression by Negatively Regulating the p53 Signaling Pathway

Identification of Prognostic Immune Genes in Bladder Urothelial Carcinoma

Background

The aim of this study is to identify possible prognostic-related immune genes in bladder urothelial carcinoma and to try to predict the prognosis of bladder urothelial carcinoma based on these genes.

Methods

The Cancer Genome Atlas (TCGA) expression profile data and corresponding clinical traits were obtained. Differential gene analysis was performed using R software. Reactome was used to analyze the pathway of immune gene participation. The differentially expressed transcription factors and differentially expressed immune-related genes were extracted from the obtained list of differentially expressed genes, and the transcription factor-immune gene network was constructed. To analyze the relationship between immune genes and clinical traits of bladder urothelial carcinoma, a multifactor Cox proportional hazards regression model based on the expression of immune genes was established and validated.

Results

Fifty-eight immune genes were identified to be associated with the prognosis of bladder urothelial carcinoma. These genes were enriched in Cytokine Signaling in Immune System, Signaling by Receptor Tyrosine Kinases, Interferon alpha/beta signaling, and other immune related pathways. Transcription factor-immune gene regulatory network was established, and EBF1, IRF4, SOX17, MEF2C, NFATC1, STAT1, ANXA6, SLIT2, and IGF1 were screened as hub genes in the network. The model calculated by the expression of 16 immune genes showed a good survival prediction ability (p < 0.05 and AUC = 0.778).

Conclusion

A transcription factor-immune gene regulatory network related to the prognosis of bladder urothelial carcinoma was established. EBF1, IRF4, SOX17, MEF2C, NFATC1, STAT1, ANXA6, SLIT2, and IGF1 were identified as hub genes in the network. The proportional hazards regression model constructed by 16 immune genes shows a good predictive ability for the prognosis of bladder urothelial carcinoma.

RAPTOR promotes colorectal cancer proliferation by inducing mTORC1 and upregulating ribosome assembly factor URB1

Mammalian target of rapamycin complex 1 (mTORC1) is evolutionally conserved and frequently activated in various tumors, including colorectal cancer (CRC). It has been reported that the ribosome assembly factor Urb1 acts downstream of mTORC1/raptor signaling and contributes to digestive organ development in zebrafish. Previously, we highlighted that URB1 was overexpressed in CRC. Here, we assessed the mTORC1/regulatory associated protein with mTOR (RAPTOR)-URB1 axis in CRC tumorigenesis. We found that RAPTOR was overexpressed in CRC tissues and cell lines, was a favorable predictor in patients with CRC, and positively correlated with URB1. Silencing of RAPTOR suppressed CRC cell proliferation and migration and induced cell cycle arrest and apoptosis in vitro and inhibited xenograft growth in vivo. Moreover, ectopic overexpression of RAPTOR exerted an inverse biological phenotype. Knockdown of RAPTOR quenched mTORC1 activity and reduced the expression of URB1 and cyclinA2 (CCNA2). In contrast, overexpression of RAPTOR activated mTORC1 and upregulated URB1 and CCNA2. Furthermore, URB1 and CCNA2 expression were also impeded by rapamycin, which is a specific inhibitor of mTORC1. Thus, RAPTOR promoted CRC proliferation, migration, and cell cycle progression by inducing mTORC1 signaling and transcriptional activation of both URB1 and CCNA2. Taken together, we concluded that RAPTOR has the potential to serve as a novel biomarker and therapeutic target for CRC.

LINC02273 drives breast cancer metastasis by epigenetically increasing AGR2 transcription

BACKGROUND

The majority of breast cancer patients die of metastasis rather than primary tumors, whereas the molecular mechanisms orchestrating cancer metastasis remains poorly understood. Long noncoding RNAs (lncRNA) have been shown to regulate cancer occurrence and progression. However, the lncRNAs that drive metastasis in cancer patients and their underlying mechanisms are still largely unknown.

METHODS

lncRNAs highly expressed in metastatic lymph nodes were identified by microarray. Survival analysis were made by Kaplan-Meier method. Cell proliferation, migration, and invasion assay was performed to confirm the phenotype of LINC02273. Tail vein model and mammary fat pad model were used for in vivo study. RNA pull-down and RIP assay were used to confirm the interaction of hnRNPL and LINC02273. Chromatin isolation by RNA purification followed by sequencing (ChIRP-seq), RNA-seq, ChIP-seq, and luciferase reporter assay reveal hnRNPL-LINC02273 regulates AGR2. Antisense oligonucleotides were used for in vivo treatment.

RESULTS

We identified a novel long noncoding RNA LINC02273, whose expression was significantly elevated in metastatic lesions compared to the primary tumors, by genetic screen of matched tumor samples. Increased LINC02273 promoted breast cancer metastasis in vitro and in vivo. We further showed that LINC02273 was stabilized by hnRNPL, a protein increased in metastatic lesions, in breast cancer cells. Mechanistically, hnRNPL-LINC02273 formed a complex which activated AGR2 transcription and promoted cancer metastasis. The recruitment of hnRNPL-LINC02273 complex to AGR2 promoter region epigenetically upregulated AGR2 by augmenting local H3K4me3 and H3K27ac levels. Combination of AGR2 and LINC02273 was an independent prognostic factor for predicting breast cancer patient survival. Moreover, our data revealed that LINC02273-targeting antisense oligonucleotides (ASO) substantially inhibited breast cancer metastasis in vivo.

CONCLUSIONS

Our findings uncover a key role of LINC02273-hnRNPL-AGR2 axis in breast cancer metastasis and provide potential novel therapeutic targets for metastatic breast cancer intervention.

Celecoxib Inhibits Hepatocellular Carcinoma Cell Growth and Migration by Targeting PNO1

Background

Celecoxib has shown anti-tumor activities against several types of cancer. Although the majority of research focuses on its mechanism via cyclooxygenase-2 (COX-2) enzyme inhibition, we identified a distinct mechanism behind celecoxib anti-cancer abilities.

Material/Methods

We treated hepatocellular carcinoma (HCC) Huh-7 cells and tumor xenograft mice models with celecoxib to test its effects on the tumor. Using gene chip method to identify the differential expressed genes after celecoxib treatment and using pathway enrichment analysis to predict the potential pathways for further study. We transfected cells with lentiviral shRNA to detect the effect of RNA binding gene partner of NOB1 (PNO1) on tumor growth in vitro and in vivo. Further we performed western blot to detect the effect of PNO1 on the protein kinase B (AKT) pathway.

Results

Celecoxib inhibited HCC cell growth in vitro and in vivo, and gene chip and pathway enrichment analysis revealed that PNO1 may be the potential target of celecoxib in HCC cells. Celecoxib significantly reduced levels of PNO1 in tumor tissue. Knockdown of PNO1 remarkably suppressed tumor growth and metastasis in vitro and in vivo. Disruption of PNO1 expression significantly reduced protein kinase B (AKT)/rapamycin (mTOR) signaling, indicating that this pathway may be involved in PNO1-mediated tumorigenic activity.

Conclusions

Celecoxib may exert its anti-tumor activity by inhibiting PNO1, and that AKT/mTOR signaling helps mediate the oncogenic effects of PNO1. This work offers the first evidence for a role of PNO1 as an HCC oncogene, which may open new avenues for prevention and treatment of HCC.