Ribosome assembly factor PNO1 is associated with progression and promotes tumorigenesis in triple‑negative breast cancer

Identification of hub genes and diagnostic efficacy for triple-negative breast cancer through WGCNA and Mendelian randomization

OBJECTIVE

Triple-negative breast cancer (TNBC) represents a particularly aggressive form of breast cancer with a poor prognosis due to a lack of targeted treatments resulting from limited a understanding of the underlying mechanisms. The aim of this study was the identification of hub genes for TNBC and assess their clinical applicability in predicting the disease.

METHODS

This study employed a combination of weighted gene co-expression network analysis (WGCNA) and differentially expressed genes (DEGs) to identify new susceptible modules and central genes in TNBC. The potential functional roles of the central genes were investigated using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses. Furthermore, a predictive model and ROC curve were developed to assess the diagnostic performance of the identified central genes. The correlation between CCNB1 and immune cells proportion was also investigated. At last, a Mendelian randomization (MR) analysis utilizing Genome-Wide Association Study (GWAS) data was analyzed to establish the causal effect of CCNB1 level on TNBC.

RESULTS

WGCNA was applied to determine gene co-expression maps and identify the most relevant module. Through a screening process, 1585 candidate hub genes were subsequently identified with WGCNA and DEGs. GO and KEGG function enrichment analysis indicated that these core genes were related to various biological processes, such as organelle fission, chromosome segregation, nuclear division, mitotic cell cycle phase transition, the cell cycle, amyotrophic lateral sclerosis, and motor proteins. Using STRING and Cytoscape, the top five genes with high degrees were identified as CDC2, CCNB1, CCNA2, TOP2A, and CCNB2. The nomogram model demonstrated good performance in predicting TNBC risk and was proven effective in diagnosis, as evidenced by the receiver operating characteristic (ROC) curve. Further investigation revealed a causal association between CCNB1 and immune cell infiltrates in TNBC. Survival analysis revealed high expression of the CCNB1 gene leads to poorer prognosis in TNBC patients. Additionally, analysis using inverse variance weighting revealed that CCNB1 was linked to a 2.8% higher risk of TNBC (OR: 1.028, 95% CI 1.002-1.055, p = 0.032).

CONCLUSION

We established a co-expression network using the WGCNA methodology to detect pivotal genes associated with TNBC. This finding holds promise for advancing the creation of pre-symptomatic diagnostic tools and deepening our comprehension of the pathogenic mechanisms involved in TNBC risk genes.

Pien Tze Huang Inhibits Proliferation of Colorectal Cancer Cells through Suppressing PNO1 Expression and Activating p53/p21 Signaling Pathway

OBJECTIVE

To explore the regulatory effect of Pien Tze Huang (PZH) on targeting partner of NOB1 (PNO1) and it's down-stream mediators in colorectal cancer (CRC) cells.

METHODS

Quantitative polymerase chain reaction was performed to determine mRNA levels of PNO1, TP53, and CDKN1A. Western blotting was performed to determine protein levels of PNO1, p53, and p21. HCT-8 cells were transduced with a lentivirus over-expressing PNO1. Colony formation assay was used to detect cell survival in PNO1 overexpression of HCT-8 cells after PZH treatment. Cell-cycle distribution, cell viability and cell apoptosis were performed to identify the effect of PNO1 overexpression on cell proliferation and apoptosis of HCT-8 cells after PZH treatment. Xenograft BALB/c nude mice bearing HCT116 cells transduced with sh-PNO1 or sh-Ctrl lentivirus were evaluated. Western blot assay was performed to detect PNO1, p53, p21 and PCNA expression in tumor sections. Terminal deoxynucleotidyl transferase dUTP nick end labling (TUNEL) assay was used to determine the apoptotic cells in tissues.

RESULTS

PZH treatment decreased cell viability, down-regulated PNO1 expression, and up-regulated p53 and p21 expressions in HCT-8 cells (P<0.05). PNO1 overexpression attenuated the effects of PZH treatment, including the expression of p53 and p21, cell growth, cell viability, cell cycle arrest and cell apoptosis in vitro (P<0.05). PNO1 knockdown eliminated the effects of PZH treatment on tumor growth, inhibiting cell proliferation inhibition and apoptosis induction in vivo (P<0.05). Similarly, PNO1 knockdown attenuated the effects of PZH treatment on the down-regulation of PNO1 and up-regulation of p53 and p21 in vivo (P<0.05).

CONCLUSION

The mechanism by which PZH induces its CRC anti-proliferative effect is at least in part by regulating the expression of PNO1 and its downstream targets p53 and p21.

PNO1 promotes the progression of osteosarcoma via TGF-β and YAP/TAZ pathway

This study aimed to explore the potential role and mechanisms of the partner of NOB1 homolog (PNO1) in osteosarcoma. The expression of PNO1 in tumor and adjacent tissue samples was examined using western blotting. Lentiviral transfection was used to establish sh-Ctrl and sh-PNO1 osteosarcoma cell lines. MTT assay, Celigo cell cytometer count, and cell colony formation assay were used to investigate the proliferation of osteosarcoma cells in vitro, whereas xenotransplantation assay was performed for in vivo experiments. Wound-healing and Transwell assays were chosen to verify the migration and invasion of osteosarcoma cells. Flow cytometry assay and caspase-3/7 activity analysis were adopted for the analysis of cell apoptosis and cell cycle. Finally, transcriptome sequencing and bioinformatics analysis were adopted to explore the acting mechanisms. The expression of PNO1 was higher in osteosarcoma tissues than that in adjacent tissues. Down-regulation of PNO1 inhibited the proliferation, migration, and invasion, and induced cell apoptosis and cell cycle arrest of osteosarcoma cells. Furthermore, according to transcriptome sequencing and Kyoto Encyclopedia of Genes and Genomes pathway analysis, we found that PNO1 might affect the progression of osteosarcoma via TGF-β and YAP/TAZ signaling pathways. PNO1 could be a potential target for osteosarcoma treatment.

Partner of NOB1 homolog transcriptionally activated by E2F transcription factor 1 promotes the malignant progression and inhibits ferroptosis of pancreatic cancer

Pancreatic cancer (PC) is one of the deadliest malignancies. Partner of NOB1 homolog (PNO1) has been reported to be involved in tumorigenesis. However, the role of PNO1 in PC remains to be elucidated. The purpose of this study was to examine the effects of PNO1 on the progression of PC and the possible mechanism related to E2F transcription factor 1 (E2F1), a transcription factor predicted by the JASPAR database to bind to the PNO1 promoter region and promoted the proliferation of pancreatic ductal adenocarcinoma. First, PNO1 expression in PC tissues and its association with survival rate were analyzed by the Gene Expression Profiling Interactive Analysis database. Western blot and reverse transcription-quantitative polymerase chain reaction were used to evaluate PNO1 expression in several PC cell lines. After PNO1 silencing, cell proliferation, migration, and invasion were measured by colony formation assay, 5-ethynyl-2'-deoxyuridine staining, wound healing, and transwell assays. Then, the lipid reactive oxygen species in PANC-1 cells was estimated by using C11-BODIPY581/591 probe. The levels of glutathione, malondialdehyde, and iron were measured. The binding between PNO1 and E2F1 was confirmed by luciferase and chromatin immunoprecipitation (ChIP) assays. Subsequently, E2F1 was overexpressed in PANC-1 cells with PNO1 knockdown to perform the rescue experiments. Results revealed that PNO1 was highly expressed in PC tissues and PNO1 expression was positively correlated with overall survival rate and disease-free survival rate. Significantly elevated PNO1 expression was also observed in PC cell lines. PNO1 knockdown inhibited the proliferation, migration, and invasion of PANC-1 cells. Moreover, ferroptosis was promoted in PNO1-silenced PANC-1 cells. Results of luciferase and ChIP assays indicated that E2F1 could bind to PNO1 promoter region. Rescue experiments suggested that E2F1 overexpression reversed the impacts of PNO1 depletion on the malignant behaviors and ferroptosis in PANC-1 cells. Summing up, PNO1 transcriptionally activated by E2F1 promotes the malignant progression and inhibits the ferroptosis of PC.

Current and novel approaches in the pharmacological treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal malignant tumours worldwide. The mortality-to-incidence ratio is up to 91.6% in many countries, representing the third leading cause of cancer-related deaths. Systemic drugs, including the multikinase inhibitors sorafenib and lenvatinib, are first-line drugs used in HCC treatment. Unfortunately, these therapies are ineffective in most cases due to late diagnosis and the development of tumour resistance. Thus, novel pharmacological alternatives are urgently needed. For instance, immune checkpoint inhibitors have provided new approaches targeting cells of the immune system. Furthermore, monoclonal antibodies against programmed cell death-1 have shown benefits in HCC patients. In addition, drug combinations, including first-line treatment and immunotherapy, as well as drug repurposing, are promising novel therapeutic alternatives. Here, we review the current and novel pharmacological approaches to fight HCC. Preclinical studies, as well as approved and ongoing clinical trials for liver cancer treatment, are discussed. The pharmacological opportunities analysed here should lead to significant improvement in HCC therapy.

Inhibition of ribosome assembly factor PNO1 by CRISPR/Cas9 technique suppresses lung adenocarcinoma and Notch pathway: Clinical application

Growth is crucially controlled by the functional ribosomes available in cells. To meet the enhanced energy demand, cancer cells re-wire and increase their ribosome biogenesis. The RNA-binding protein PNO1, a ribosome assembly factor, plays an essential role in ribosome biogenesis. The purpose of this study was to examine whether PNO1 can be used as a biomarker for lung adenocarcinoma and also examine the molecular mechanisms by which PNO1 knockdown by CRISPR/Cas9 inhibited growth and epithelial-mesenchymal transition (EMT). The expression of PNO1 was significantly higher in lung adenocarcinoma compared to normal lung tissues. PNO1 expression in lung adenocarcinoma patients increased with stage, nodal metastasis, and smoking. Lung adenocarcinoma tissues from males expressed higher PNO1 than those from females. Furthermore, lung adenocarcinoma tissues with mutant Tp53 expressed higher PNO1 than those with wild-type Tp53, suggesting the influence of Tp53 status on PNO1 expression. PNO1 knockdown inhibited cell viability, colony formation, and EMT, and induced apoptosis. Since dysregulated signalling through the Notch receptors promotes lung adenocarcinoma, we measured the effects of PNO1 inhibition on the Notch pathway. PNO1 knockdown inhibited Notch signalling by suppressing the expression of Notch receptors, their ligands, and downstream targets. PNO1 knockdown also suppressed CCND1, p21, PTGS-2, IL-1α, IL-8, and CXCL-8 genes. Overall, our data suggest that PNO1 can be used as a diagnostic biomarker, and also can be an attractive therapeutic target for the treatment of lung adenocarcinoma.