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

Periodic tryptophan protein 1 promotes colorectal cancer growth via ribosome biogenesis

BACKGROUND

Periodic tryptophan protein 1 (PWP1) is a member of the WD-40 family, located at the nucleus. The study of PWP1 in malignant tumors is at the initial stage. Its role and mechanism in colorectal cancer (CRC) remain unclear.

METHODS

KEGG pathway analysis were used for bioinformatics analysis. The protein expression of PWP1 in the tissue microarrays was detected by immunohistochemical methods. Colony and CCK-8 were used for PWP1 function in vitro, and the orthotopic model was used to assess PWP1 function in vivo. The growth of CRC was tracked by the Living Imaging System. Immunofluorescence was used for the quantification of nascent rRNAs. Polysome fractionation analysis was used to detect mRNA abundance.

RESULTS

GEO database was used to identify differential genes with elevated expression in CRC and followed by a KEGG analysis, which revealed that the ribosome synthesis pathway was enriched in CRC, with PWP1 displaying the most significant differential expression. Subsequently, the results of both in vitro and in vivo experiments demonstrated that PWP1 knockdown inhibited the proliferation of CRC. The results of immunofluorescence demonstrated that PWP1 knockdown suppressed de novo rRNA synthesis. Then, the differential proteins were examined, and this revealed that the most significantly downregulated proteins were those associated with DNA replication and mismatch repair functions following PWP1 interference. Moreover, ribosome profiling demonstrated significant downregulation of mRNAs associated with above functions.

CONCLUSION

We found that the PWP1-ribosome synthesis pathway is instrumental in achieving precise regulation of downstream signaling pathways, which in turn promote CRC growth.

Downregulating FGGY carbohydrate kinase domain containing promotes cell senescence by activating the p53/p21 signaling pathway in colorectal cancer

Carbohydrate kinases serve an oncogenic role in several types of cancer; however, the function of FGGY carbohydrate kinase domain containing (FGGY) in colorectal cancer (CRC) remains unknown. The present study investigated the function and possible molecular mechanisms of FGGY in CRC. The results showed that elevated levels of FGGY mRNA and protein were observed in CRC tissues, and a higher expression of FGGY was associated with advanced N stage and reduced overall survival time in patients with CRC. Silencing FGGY inhibited the viability of CRC cells by inducing cell cycle arrest and promoting apoptosis in vitro, thereby attenuating tumor growth in a xenograft mouse model. FGGY knockdown also enriched the senescence‑associated heterochromatin foci (SAHF) pathway and p53 pathway, as further confirmed by enhancing senescence‑associated β‑galactosidase (SA‑β‑gal) activity, with increased levels of SAHF‑associated proteins HP1γ and trimethylation of H3K9 (H3k9me3) in CRC cells, as well as upregulation of p53 and its downstream protein p21. Furthermore, p53 knockout rescued FGGY knockdown‑mediated reductions in cell viability, SA‑β‑gal activity, and the levels of HP1γ and H3k9me3 in CRC cells. These findings indicated that FGGY could act as a newly identified potential oncogene in CRC, partially through regulating the p53/p21 signaling pathway and altering cell senescence.

Effect of SNORD113-3/ADAR2 on glycolipid metabolism in glioblastoma via A-to-I editing of PHKA2

BACKGROUND

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor, characterized by its poor prognosis. Glycolipid metabolism is strongly associated with GBM development and malignant behavior. However, the precise functions of snoRNAs and ADARs in glycolipid metabolism within GBM cells remain elusive. The objective of the present study is to delve into the underlying mechanisms through which snoRNAs and ADARs exert regulatory effects on glycolipid metabolism in GBM cells.

METHODS

RNA immunoprecipitation and RNA pull-down experiments were conducted to verify the homodimerization of ADAR2 by SNORD113-3, and Sanger sequencing and Western blot experiments were used to detect the A-to-I RNA editing of PHKA2 mRNA by ADAR2. Furthermore, the phosphorylation of EBF1 was measured by in vitro kinase assay. Finally, in vivo studies using nude mice confirmed that SNORD113-3 and ADAR2 overexpression, along with PHKA2 knockdown, could suppress the formation of subcutaneous xenograft tumors and improve the outcome of tumor-bearing nude mice.

RESULTS

We found that PHKA2 in GBM significantly promoted glycolipid metabolism, while SNORD113-3, ADAR2, and EBF1 significantly inhibited glycolipid metabolism. SNORD113-3 promotes ADAR2 protein expression by promoting ADAR2 homodimer formation. ADAR2 mediates the A-to-I RNA editing of PHKA2 mRNA. Mass spectrometry analysis and in vitro kinase testing revealed that PHKA2 phosphorylates EBF1 on Y256, reducing the stability and expression of EBF1. Furthermore, direct binding of EBF1 to PKM2 and ACLY promoters was observed, suggesting the inhibition of their expression by EBF1. These findings suggest the existence of a SNORD113-3/ADAR2/PHKA2/EBF1 pathway that collectively regulates the metabolism of glycolipid and the growth of GBM cells. Finally, in vivo studies using nude mice confirmed that knockdown of PHKA2, along with overexpression of SNORD113-3 and ADAR2, could obviously suppress GBM subcutaneous xenograft tumor formation and improve the outcome of those tumor-bearing nude mice.

CONCLUSIONS

Herein, we clarified the underlying mechanism involving the SNORD113-3/ADAR2/PHKA2/EBF1 pathway in the regulation of GBM cell growth and glycolipid metabolism. Our results provide a framework for the development of innovative therapeutic interventions to improve the prognosis of patients with GBM.

Antihyperlipidemic drug rosuvastatin suppressed tumor progression and potentiated chemosensitivity by downregulating CCNA2 in lung adenocarcinoma

Rosuvastatin (RSV) is widely used to treat hyperlipidemia and hypercholesterolemia and is recommended for the primary and secondary prevention of cardiovascular diseases (CVD). In this study, we aimed to explore its action and mechanism in lung adenocarcinoma (LUAD) therapy. Lewis and CMT64 cell-based murine subcutaneous LUAD models were employed to explore the effects of RSV monotherapy combined with cisplatin and gemcitabine. Human lung fibroblasts and human LUAD cell lines were used to assess the effects of RSV on normal and LUAD cells. Bioinformatics and RNA interference were used to observe the contribution of cyclin A2 (CCNA2) knockdown to RSV inhibition and to improve chemosensitivity in LUAD. RSV significantly suppressed grafted tumor growth in a murine subcutaneous LUAD model and exhibited synergistic anti-tumor activity with cisplatin and gemcitabine. In vitro and in vivo experiments demonstrated that RSV impaired the proliferation and migration of cancer cells while showing little inhibition of normal lung cells. RNA interference and CCK8 detection preliminarily indicated that RSV inhibited tumor growth and enhanced the chemosensitivity to cisplatin and gemcitabine by downregulating CCNA2. RSV suppressed LUAD progression and enhanced chemosensitivity to cisplatin and gemcitabine by downregulating CCNA2, which should be prior consideration for the treatment of LUAD, especially for patients co-diagnosed with hyperlipidemia and hypercholesterolemia.

miR-326 overexpression inhibits colorectal cancer cell growth and proteasome activity by targeting PNO1: unveiling a novel therapeutic intervention strategy

Proteasome inhibition emerges as a promising strategy for cancer prevention. PNO1, pivotal for colorectal cancer (CRC) progression, is involved in proteasome assembly in Saccharomyces cerevisiae. Hence, we aimed to explore the role of PNO1 in proteasome assembly and its up- and down-streams in CRC. Here, we demonstrated that PNO1 knockdown suppressed CRC cells growth, proteasome activities and assembly, as well as CDKN1B/p27Kip1 (p27) degradation. Moreover, p27 knockdown partially attenuated the inhibition of HCT116 cells growth by PNO1 knockdown. The up-stream studies of PNO1 identified miR-326 as a candidate miRNA directly targeting to CDS-region of PNO1 and its overexpression significantly down-regulated PNO1 protein expression, resulting in suppression of cell growth, decrease of proteasome activities and assembly, as well as increasing the stability of p27 in CRC cells. These findings indicated that miR-326 overexpression can suppress CRC cell growth, acting as an endogenous proteasome inhibitor by targeting PNO1.

Pan-cancer exploration of PNO1: A prospective prognostic biomarker with ties to immune infiltration

The partner of NOB1 homolog (PNO1) is an RNA-binding protein that participates in ribosome biogenesis and protein modification. The functions of this molecule are largely unknown in cancers, particularly breast cancer. We employed bioinformatics methods to probe the putative oncogenic functions of PNO1 based on expression profiles and clinical data from the cancer genome atlas (TCGA), genotype-tissue expression project (GTEx), human protein atlas (HPA), cancer cell line encyclopedia (CCLE), UALCAN, drug sensitivity in cancer (GDSC) and UCSC XENA databases. Our analyses revealed that PNO1 was overexpressed in 31 malignancies, which excluded kidney chromophobe (KICH) and acute myeloid leukemia (LAML). Prognostic assessments have demonstrated that high PNO1 expression was significantly correlated with poor overall and disease-specific survival in various cancers. The promoter methylation level of PNO1 is significantly decreased in breast invasive carcinoma (BRCA), head and neck squamous cell carcinoma (HNSC), kidney renal papillary cell carcinoma (KIRP), prostate adenocarcinoma (PRAD), thyroid carcinoma (THCA) and uterine corpus endometrial carcinoma (UCEC). Furthermore, inhibition of PNO1 decreased the viability, migration and invasion of breast cancer cells, and these results were confirmed by mouse xenograft models of breast cancer. In addition, we discovered that tumor microenvironment (TME), immune infiltration, and chemotherapy sensitivity were influenced by PNO1 expression. Concordantly, our analyses revealed a significant positive correlation between PNO1 and programmed cell death ligand 1 (PD-L1) expression across breast carcinoma samples. In conclusion, these findings indicate that PNO1 could act as a promising prognostic biomarker and adjunct diagnostic indicator, because it affects tumor growth and invasion. Our study offers valuable new perspectives on the oncogenic role of PNO1 in various types of cancers.

Epigenetic Biomarkers and the Wnt/β-Catenin Pathway in Opisthorchis viverrini-associated Cholangiocarcinoma: A Scoping Review on Therapeutic Opportunities

BACKGROUND

Epigenetic modifications, such as DNA methylation and histone modifications, are pivotal in regulating gene expression pathways related to inflammation and cancer. While there is substantial research on epigenetic markers in cholangiocarcinoma (CCA), Opisthorchis viverrini-induced cholangiocarcinoma (Ov-CCA) is overlooked as a neglected tropical disease (NTD) with limited representation in the literature. Considering the distinct etiological agent, pathogenic mechanisms, and pathological manifestations, epigenetic research plays a pivotal role in uncovering markers and potential targets related to the cancer-promoting and morbidity-inducing liver fluke parasite prevalent in the Great Mekong Subregion (GMS). Emerging studies highlight a predominant hypermethylation phenotype in Opisthorchis viverrini (O. viverrini) tumor tissues, underscoring the significance of abnormal DNA methylation and histone modifications in genes and their promoters as reliable targets for Ov-CCA.

PRINCIPAL FINDINGS

Relevant published literature was identified by searching major electronic databases using targeted search queries. This process retrieved a total of 81 peer-reviewed research articles deemed eligible for inclusion, as they partially or fully met the pre-defined selection criteria. These eligible articles underwent a qualitative synthesis and were included in the scoping review. Within these, 11 studies specifically explored Ov-CCA tissues to investigate potential epigenetic biomarkers and therapeutic targets. This subset of 11 articles provided a foundation for exploring the applications of epigenetics-based therapies and biomarkers for Ov-CCA. These articles delved into various epigenetic modifications, including DNA methylation and histone modifications, and examined genes with aberrant epigenetic changes linked to deregulated signalling pathways in Ov-CCA progression.

CONCLUSIONS

This review identified epigenetic changes and Wnt/β-catenin pathway deregulation as key drivers in Ov-CCA pathogenesis. Promoter hypermethylation of specific genes suggests potential diagnostic biomarkers and dysregulation of Wnt/β-catenin-modulating genes contributes to pathway activation in Ov-CCA progression. Reversible epigenetic changes offer opportunities for dynamic disease monitoring and targeted interventions. Therefore, this study underscores the importance of these epigenetic modifications in Ov-CCA development, suggesting novel therapeutic targets within disrupted signalling networks. However, additional validation is crucial for translating these novel insights into clinically applicable strategies, enhancing personalised Ov-CCA management approaches.

Focusing on the Immune Cells: Recent Advances in Immunotherapy for Biliary Tract Cancer

Biliary tract cancer (BTC) represents a challenging malignancy characterized by aggressive behavior, high relapse rates, and poor prognosis. In recent years, immunotherapy has revolutionized the treatment landscape for various cancers, but its efficacy in BTC remains limited. This article provides a comprehensive overview of the advances in preclinical and clinical studies of immunotherapy for BTC. We explore the potential of immune checkpoint inhibitors in reshaping the management of BTC. Despite disappointing results thus far, ongoing clinical trials are investigating the combination of immunotherapy with other treatment modalities. Furthermore, research on the tumor microenvironment has unveiled novel targets for immunotherapeutic interventions. By understanding the current state of immunotherapy in BTC and highlighting future directions, this article aims to fuel further exploration and ultimately improve patient outcomes in this challenging disease.

Therapeutic potential of Pien Tze Huang in colitis-associated colorectal cancer: mechanistic insights from a mouse model

BACKGROUND

Pien Tze Huang (PZH), a traditional Chinese medicine formulation, is recognized for its therapeutic effect on colitis and colorectal cancer. However, its protective role and underlying mechanism in colitis-associated colorectal cancer (CAC) remain to be elucidated.

METHODS

A CAC mouse model was established using AOM/DSS. Twenty mice were randomly divided into four groups (n = 5/group): Control, PZH, AOM/DSS, and AOM/DSS + PZH groups. Mice in the PZH and AOM/DSS + PZH group were orally administered PZH (250 mg/kg/d) from the first day of experiment, while the control and AOM/DSS group received an equivalent volume of distilled water. Parameters such as body weight, disease activity index (DAI), colon weight, colon length, colon histomorphology, intestinal tumor formation, serum concentrations of pro-inflammatory cytokines, proliferation and apoptosis in colon tissue were assessed. RNA sequencing was employed to identify the differentially expressed transcripts (DETs) in colonic tissues and related signaling pathways. Wnt/β-Catenin Pathway-Related genes in colon tissue were detected by QPCR and immunohistochemistry (IHC).

RESULTS

PZH significantly attenuated AOM/DSS-induced weight loss, DAI elevation, colonic weight gain, colon shortening, histological damage, and intestinal tumor formation in mice. PZH also notably decreased serum concentration of IL-6, IL-1β, and TNF-α. Furthermore, PZH inhibited cell proliferation and promote apoptosis in tumor tissues. RNA-seq and KEGG analysis revealed key pathways influenced by PZH, including Wnt/β-catenin signaling pathway. IHC staining confirmed that PZH suppressed the expression of β-catenin, cyclin D1 and c-Myc in colonic tissues.

CONCLUSIONS

PZH ameliorates AOM/DSS-induced CAC in mice by suppressing the activation of Wnt/β-catenin signaling pathway.

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.

Clinical significance of PNO1 as a novel biomarker and therapeutic target of hepatocellular carcinoma

The RNA-binding protein PNO1 plays an essential role in ribosome biogenesis. Recent studies have shown that it is involved in tumorigenesis; however, its role in hepatocellular carcinoma (HCC) is not well understood. The purpose of this study was to examine whether PNO1 can be used as a biomarker of HCC and also examine the therapeutic potential of PNO1 knockout for the treatment of HCC. PNO1 expression was upregulated in HCC and associated with poor prognosis. PNO1 expression was positively associated with tumour stage, lymph node metastasis and poor survival. PNO1 expression was significantly higher in HCC compared to that in fibrolamellar carcinoma or normal tissues. Furthermore, HCC tissues with mutant Tp53 expressed higher PNO1 than those with wild-type Tp53. PNO1 knockout suppressed cell viability, colony formation and EMT of HCC cells. Since activation of Notch signalling pathway promotes HCC, we measured the effects of PNO1 knockout on the components of Notch pathway and its targets. PNO1 knockout suppressed Notch signalling by modulating the expression of Notch ligands and their receptors, and downstream targets. PNO1 knockout also inhibited genes involved in surface adhesion, cell cycle, inflammation and chemotaxis. PNO1 knockout also inhibited colony and spheroid formation, cell migration and invasion, and markers of stem cells, pluripotency and EMT in CSCs. Overall, our data suggest that PNO1 can be used as a diagnostic and prognostic biomarker of HCC, and knockout of PNO1 by CRISPR/Cas9 can be beneficial for the management of HCC by targeting CSCs.

Ribosome Biogenesis and Cancer: Insights into NOB1 and PNO1 Mechanisms

Post-transcriptional modifications (PTMs) are pivotal in the regulation of gene expression, and pseudouridylation is emerging as a critical player. This modification, facilitated by enzymes such as NOB1 (PNO1), is integral to ribosome biogenesis. PNO1, in collaboration with the NIN1/RPN12 binding protein 1 homolog (NOB1), is vital for the maturation of ribosomes, transitioning 20S pre-rRNA into functional 18S rRNA. Recent studies have highlighted PNO1's potential involvement in cancer progression; however, its underlying mechanisms remain unclear. Relentless growth characterizing cancer underscores the burgeoning significance of epitranscriptomic modifications, including pseudouridylation, in oncogenesis. Given PNO1's emerging role, it is imperative to delineate its contribution to cancer development to identify novel therapeutic interventions. This review summarizes the current literature regarding the role of PNO1 in cancer progression and its molecular underpinnings in oncogenesis. Overexpression of PNO1 was associated with unfavorable prognosis and increased tumor malignancy. At the molecular level, PNO1 facilitates cancer progression by modulating mRNA stability, alternative splicing, and translation efficiency. Its role in pseudouridylation of oncogenic and tumor-suppressor transcripts further underscores its significance in cancer biology. Although disruption of ribosome biogenesis is known to precipitate oncogenesis, the precise mechanisms by which these alterations contribute to cancer remain unclear. This review elucidates the intricate process of ribosomal small subunit maturation, highlighting the roles of crucial ribosomal proteins (RPs) and RNA-binding proteins (RBPs) as well as the positioning and function of NOB1 and PNO1 within the 40S subunit. The involvement of these components in the maturation of the small subunit (SSU) and their significance in the context of cancer therapeutics has been thoroughly explored. PNO1's burgeoning significance in oncology makes it a potential target for cancer therapies. Strategies aimed at modulating PNO1-mediated pseudouridylation may provide new avenues for cancer treatment. However, further research is essential to unravel the complete spectrum of PNO1 mechanisms in cancer and harness this knowledge for the development of targeted and more efficacious anticancer therapies.

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.

Breast cancer-derived exosomal lncRNA SNHG14 induces normal fibroblast activation to cancer-associated fibroblasts via the EBF1/FAM171A1 axis

BACKGROUND

Exosomes released from cancer cells can activate normal fibroblasts (NFs) into cancer-associated fibroblasts (CAFs), which promotes cancer development. Our study aims to explore the role and potential mechanisms of breast cancer exosomes-delivered long non-coding RNA (lncRNA) SNHG14 in regulating CAFs transformation.

METHODS

Adjacent normal tissues, cancerous and serum specimens were gathered in breast cancer patients. Exosomes and NFs were separated from breast cancer cells (SKBR-3) and normal tissues of patients, respectively. Cell viability and migration were measured with CCK-8 and Transwell assays. CAFs markers, fibroblast activation protein (FAP) and a-smooth muscle actin (α-SMA) were detected for assessing CAFs activation. The interactions between molecules were evaluated using dual luciferase reporter assay, RNA immunoprecipitation and chromatin immunoprecipitation.

RESULTS

SNHG14 and FAM171A1 were upregulated in breast cancer. Exosomes secreted by SKBR-3 cells induced NFs activation in CAFs, as indicated by upregulating CAFs marker levels and facilitated cell viability and migration. Exosomal SNHG14 silencing in SKBR-3 cells inhibited CAFs activation. SNHG14 positively regulated FAM171A1 expression through EBF1. FAM171A1 overexpression eliminated the inhibition effect of exosomal SNHG14 silencing in CAFs transformation.

CONCLUSION

Breast cancer-derived exosomal SNHG14 contributed to NFs transformation into CAFs by the EBF1/FAM171A1 axis.

Circ_0004676 exacerbates triple-negative breast cancer progression through regulation of the miR-377-3p/E2F6/PNO1 axis

BACKGROUND

The significant roles of circular RNAs (circRNAs) in different cancers and diseases have been reported. We now focused on the possible role of a newly recognized circRNA, circ_0004674 in triple-negative breast cancer (TNBC), and the related downstream mechanism.

METHODS

The expression of circ_0004674 in TNBC tissues and cells was determined followed by analysis of the correlation between circ_0004674 and TNBC patients' prognosis. The interaction between circ_0004674, miR-377-3p, E2F6, and PNO1 was then identified using bioinformatics analysis combined with FISH, RIP, RNA pull-down, RT-qPCR, and Western blot analysis. Using gain-of-function and loss-of-function methods, we analyzed the effect of circ_0004674, miR-377-3p, E2F6, and PNO1 on TNBC in vivo and in vitro.

RESULTS

Increased circ_0004674 and E2F6 but decreased miR-377-3p were observed in TNBC tissues and MDA-MB-231 TNBC cells, all of which findings were associated with poor prognosis in patients with TNBC. Silencing of circ_0004676 remarkably suppressed the proliferation, cell cycle progression, and migration of TNBC cells in vitro, as well as inhibiting tumorigenesis and metastasis in vivo. Additionally, circ_0004676 served as a sponge of miR-377-3p which bound to the transcription factor E2F6. In the presence of overexpression of circ_0004676, E2F6 expression and its target PNO1 expression were elevated, while miR-377-3p expression was decreased. Interestingly, overexpression of E2F6 could reverse the inhibitory effect on tumor growth caused by downregulation of circ_0004676.

CONCLUSION

Our study highlighted the carcinogenic effect of circ_0004676 on TNBC through regulation of the miR-377-3p/E2F6/PNO1 axis. 1. Circ_0004674 is highly expressed in TNBC tissues and cells. 2. Circ_0004674 upregulates the expression of E2F6 by sponging miR-377-3p. 3. E2F6 upregulates PNO1 by binding to the PNO1 promoter. 4. Circ_0004674 favors TNBC progression by regulating the miR-377-3p/E2F6/PNO1 axis. 5. This study provides a new target for the treatment of TNBC.

SNTB1 regulates colorectal cancer cell proliferation and metastasis through YAP1 and the WNT/β-catenin pathway

Colorectal cancer is a common type of digestive tract cancer with a significant morbidity and death rate across the world, partially attributing to the metastasis-associated problems. In this study, integrative bioinformatics analyses were performed to identify genes that might contribute to colorectal cancer metastasis, and 293 genes were dramatically increased and 369 genes were decreased within colon cancer samples. Among up-regulated genes, top five genes correlated with colorectal cancer patient's prognosis were verified for expression in clinical samples and syntrophin beta 1 (SNTB1) was the most up-regulated. In vitro, SNTB1 knockdown suppresses the malignant behaviors of colorectal cancer cells, including cell viability, colony formation capacity, as well as the abilities to migrate and invade. Furthermore, SNTB1 knockdown decreased the levels of Wnt1, C-Jun, C-Myc, TCF7, and cyclin D1, and inhibited EMT in both cell lines. In vivo, SNTB1 knockdown inhibited tumor growth and metastasis in nude mice models. SNTB1 positively regulated Yes1 associated transcriptional regulator (YAP1) expression; YAP1 partially reversed the effects of SNTB1 on colorectal cancer cell phenotypes and the Wnt/β-catenin/MYC signaling. In conclusion, SNTB1 knockdown inhibits colorectal cancer cell aggressiveness in vitro and tumor growth and metastasis in vivo through the Wnt/β-catenin/MYC signaling; YAP1 might mediate SNTB1 functions on colorectal cancer.

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.

ZNF521/EBF1 axis regulates AKR1B1 to promote the proliferation, migration, and invasion of gastric cancer cells

Although the incidence and death rates of gastric cancer (GC) are decreasing, approximately one million new cases and 800,000 GC-related deaths were reported worldwide in 2018. Currently, the oncogenesis of GC remains unclear, and the demand for novel treatment options are unmet. Here, we explored the role of aldo-keto reductase family 1 member B (AKR1B1) in the progression of GC. The proliferation, migration, and invasion of GC cells were evaluated by CCK-8 assay, wound healing assay, and transwell assay, respectively. The interaction between EBF transcription factor 1 (EBF1) and the promoter region of AKR1B1 was determined by luciferase reporter assay and chromatin immunoprecipitation (ChIP). Gene expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting assay. The expression of AKR1B1 was elevated in GC cells, resulting in increased cell proliferation, migration, and invasion. Meanwhile, EBF1 was a negative regulator of AKR1B1; its overexpression suppressed AKR1B1 expression and GC progression. Furthermore, knockdown of ZNF521 induced EBF1 expression, thus suppressing AKR1B1 expression and resulting in attenuated GC growth and invasiveness. Notably, knockdown of ZNF521 attenuated GC progression and was rescued by overexpression of AKR1B1. Our current study revealed a novel ZNF521/EBF1/AKR1B1 axis in GC and elaborated its important role in promoting GC progression, providing potential therapeutic targets for anti-GC treatments.

Mechanistic insights into zearalenone-accelerated colorectal cancer in mice using integrative multi-omics approaches

Zearalenone (ZEA), a secondary metabolite of Fusarium fungi found in cereal-based foods, promotes the growth of colon, breast, and prostate cancer cells in vitro. However, the lack of animal studies hinders a deeper mechanistic understanding of the cancer-promoting effects of ZEA. This study aimed to determine the effect of ZEA on colon cancer progression and its underlying mechanisms. Through integrative analyses of transcriptomics, metabolomics, metagenomics, and host phenotypes, we investigated the impact of a 4-week ZEA intervention on colorectal cancer in xenograft mice. Our results showed a twofold increase in tumor weight with the 4-week ZEA intervention. ZEA exposure significantly increased the mRNA and protein levels of BEST4, DGKB, and Ki67 and the phosphorylation levels of ERK1/2 and AKT. Serum metabolomic analysis revealed that the levels of amino acids, including histidine, arginine, citrulline, and glycine, decreased significantly in the ZEA group. Furthermore, ZEA lowered the alpha diversity of the gut microbiota and reduced the abundance of nine genera, including Tuzzerella and Rikenella. Further association analysis indicated that Tuzzerella was negatively associated with the expression of BEST4 and DGKB genes, serum uric acid levels, and tumor weight. Additionally, circulatory hippuric acid levels positively correlated with tumor weight and the expression of oncogenic genes, including ROBO3, JAK3, and BEST4. Altogether, our results indicated that ZEA promotes colon cancer progression by enhancing the BEST4/AKT/ERK1/2 pathway, lowering circulatory amino acid concentrations, altering gut microbiota composition, and suppressing short chain fatty acids production.

EXOSC8 promotes colorectal cancer tumorigenesis via regulating ribosome biogenesis-related processes

Extensive protein synthesis is necessary for uncontrolled cancer cell proliferation, requiring hyperactive ribosome biogenesis. Our previous Pan-cancer study has identified EXOSC8 as a potential copy number variation (CNV)-driven rRNA metabolism-related oncogene in colorectal cancer (CRC). Herein, we further investigated proliferation-prompting functions and mechanisms of EXOSC8 in CRC by performing in silico analyses and wet-lab experiments. We uncovered that increased EXOSC8 expression and CNV levels are strongly associated with ribosome biogenesis-related factor levels in CRC, including ribosome proteins (RPs), eukaryotic translation initiation factors and RNA polymerase I/III. EXOSC8 silence decreases nucleolar protein and proliferation marker levels, as well as rRNA/DNA and global protein syntheses. Clinically, EXOSC8 is upregulated across human cancers, particularly CNV-driven upregulation in CRC was markedly associated with poor clinical outcomes. Mechanistically, EXOSC8 knockdown increased p53 levels in CRC, and the oncogenic proliferation phenotypes of EXOSC8 depended on p53 in vitro and in vivo. We discovered that EXOSC8 knockdown in CRC cells triggers ribosomal stress, nucleolar RPL5/11 being released into the nucleoplasm and "hijacking" Mdm2 to block its E3 ubiquitin ligase function, thus releasing and activating p53. Furthermore, our therapeutic experiments provided initial evidence that EXOSC8 might serve as a potential therapeutic target in CRC. Our findings revealed, for the first time, that the RNA exosome gene (EXOSC8) promotes CRC tumorigenesis by regulating cancer-related ribosome biogenesis in CRC. This study further extends our previous Pan-cancer study of the rRNA metabolism-related genes. The inhibition of EXOSC8 is a novel therapeutic strategy for the RPs-Mdm2-p53 ribosome biogenesis surveillance pathway in CRC.

Pan-cancer analyses reveal multi-omics and clinical characteristics of RIO kinase 2 in cancer

RIO kinase 2 has emerged as a critical kinase for ribosome maturation, and recently it has also been found to play a fundamental role in cancer, being involved in the occurrence and progression of glioblastoma, liver cancer, prostate cancer, non-small cell lung cancer, and acute myeloid leukemia. However, our knowledge in this regard is fragmented and limited and it is difficult to determine the exact role of RIO kinase 2 in tumors. Here, we conducted an integrated pan-cancer analysis comprising 33 cancer-types to determine the function of RIO kinase 2 in malignancies. The results show that RIO kinase 2 is highly expressed in all types of cancer and is significantly associated with tumor survival, metastasis, and immune cell infiltration. Moreover, RIO kinase 2 alteration via DNA methylation, and protein phosphorylation are involved in tumorigenesis. In summary, RIO kinase two serves as a promising target for the identification of cancer and increases our understanding of tumorigenesis and cancer progression and enhancing the ultimate goal of improved treatment for these diseases.

Promoter hypermethylation of GALR1 acts as an early epigenetic susceptibility event in colorectal carcinogenesis

Epigenetics play an essential role in colorectal neoplasia process. There is a need to determine the appropriateness of epigenetic biomarkers for early detection as well as expand our understanding of the carcinogenic process. Therefore, the aim of the study was to assess how DNA methylation pattern of GALR1 gene evolves in a sample set representing colorectal neoplastic progression. The study was designed into three phases. Firstly, Methylation status of GALR1 was assessed with genome-wide DNA methylation beadchip and pyrosequencing assays in colorectal lesions and paired normal tissues. Then, linear mixed-effects modeling analyses were applied to describe the trend of DNA methylation during the progression of colorectal neoplasia. In the third phase, quantitative RT-PCR was used to examine GALR1 expression in patients with precursor lesion and colorectal cancer. We found that significant hypermethylation of GALR1 promoter was a widely existent modification in CRCs (P < 0.001). When further examined methylation pattern of GALR1 during neoplastic progression of CRC, we found that DNA methylation level of GALR1 showed a significant stepwise increase from normal to hyperplastic polyps, to adenomas and to carcinoma samples (P < 0.001). Besides, loss of mRNA expression is a common accompaniment to adenomas and carcinomas. Public omics data analyses showed an inverse correlation between gene expression and DNA methylation (P < 0.001). Our findings indicate that epigenetic alteration of GALR1 promoter is gradually accumulated during the colorectal neoplastic progression. It can potentially be a promising biomarker used for screening and surveillance of colorectal cancer.

Identifying General Tumor and Specific Lung Cancer Biomarkers by Transcriptomic Analysis

The bioinformatic pipeline previously developed in our research laboratory is used to identify potential general and specific deregulated tumor genes and transcription factors related to the establishment and progression of tumoral diseases, now comparing lung cancer with other two types of cancer. Twenty microarray datasets were selected and analyzed separately to identify hub differentiated expressed genes and compared to identify all the deregulated genes and transcription factors in common between the three types of cancer and those unique to lung cancer. The winning DEGs analysis allowed to identify an important number of TFs deregulated in the majority of microarray datasets, which can become key biomarkers of general tumors and specific to lung cancer. A coexpression network was constructed for every dataset with all deregulated genes associated with lung cancer, according to DAVID’s tool enrichment analysis, and transcription factors capable of regulating them, according to oPOSSUM´s tool. Several genes and transcription factors are coexpressed in the networks, suggesting that they could be related to the establishment or progression of the tumoral pathology in any tissue and specifically in the lung. The comparison of the coexpression networks of lung cancer and other types of cancer allowed the identification of common connectivity patterns with deregulated genes and transcription factors correlated to important tumoral processes and signaling pathways that have not been studied yet to experimentally validate their role in lung cancer. The Kaplan–Meier estimator determined the association of thirteen deregulated top winning transcription factors with the survival of lung cancer patients. The coregulatory analysis identified two top winning transcription factors networks related to the regulatory control of gene expression in lung and breast cancer. Our transcriptomic analysis suggests that cancer has an important coregulatory network of transcription factors related to the acquisition of the hallmarks of cancer. Moreover, lung cancer has a group of genes and transcription factors unique to pulmonary tissue that are coexpressed during tumorigenesis and must be studied experimentally to fully understand their role in the pathogenesis within its very complex transcriptomic scenario. Therefore, the downstream bioinformatic analysis developed was able to identify a coregulatory metafirm of cancer in general and specific to lung cancer taking into account the great heterogeneity of the tumoral process at cellular and population levels.

EBF1 promotes triple-negative breast cancer progression by surveillance of the HIF1α pathway

Early B cell factor 1 (EBF1) is a transcriptional factor with a variety of roles in cell differentiation and metabolism. However, the functional roles of EBF1 in tumorigenesis remain elusive. Here, we demonstrate that EBF1 is highly expressed in triple-negative breast cancer (TNBC). Furthermore, EBF1 has a pivotal role in the tumorigenicity and progression of TNBC. Moreover, we found that depletion of EBF1 induces extensive cell mitophagy and inhibits tumor growth. Genome-wide mapping of the EBF1 transcriptional regulatory network revealed that EBF1 drives TNBC tumorigenicity by assembling a transcriptional complex with HIF1α that fine-tunes the expression of HIF1α targets via suppression of p300 activity. EBF1 therefore holds HIF1α activity in check to avert extensive mitophagy-induced cell death. Our findings reveal a key function for EBF1 as a master regulator of mitochondria homeostasis in TNBC and indicate that targeting this pathway may offer alternative treatment strategies for this aggressive subtype of breast cancer.

Chemoresistant Cancer Cell Lines Are Characterized by Migratory, Amino Acid Metabolism, Protein Catabolism and IFN1 Signalling Perturbations

Simple Summary

While chemoresistance remains a major barrier to improving the outcomes for patients with ovarian cancer, the molecular features, and associated biological functions, which underpin chemoresistance in ovarian cancer remain poorly understood. In this study we aimed to provide insight into the proteins and metabolites, and their associated biological pathways, which play a role in conferring chemoresistance to ovarian cancer. Through mass spectrometry analysis comparing the proteome and metabolome of chemosensitive vs chemoresistant ovarian cancer cell lines we revealed numerous perturbations in signalling and metabolic pathways in chemoresistant cells. Further comparison to primary cells taken from patients with chemoresistant or chemosensitive disease identified a shared dysregulation in cytokine and type 1 interferon signalling. Our research sets the foundation for a deeper understanding of the proteomic and metabolomic features of chemoresistance and identifies type 1 interferon signalling as a common feature of chemoresistance.

Abstract

Chemoresistance remains the major barrier to effective ovarian cancer treatment. The molecular features and associated biological functions of this phenotype remain poorly understood. We developed carboplatin-resistant cell line models using OVCAR5 and CaOV3 cell lines with the aim of identifying chemoresistance-specific molecular features. Chemotaxis and CAM invasion assays revealed enhanced migratory and invasive potential in OVCAR5-resistant, compared to parental cell lines. Mass spectrometry analysis was used to analyse the metabolome and proteome of these cell lines, and was able to separate these populations based on their molecular features. It revealed signalling and metabolic perturbations in the chemoresistant cell lines. A comparison with the proteome of patient-derived primary ovarian cancer cells grown in culture showed a shared dysregulation of cytokine and type 1 interferon signalling, potentially revealing a common molecular feature of chemoresistance. A comprehensive analysis of a larger patient cohort, including advanced in vitro and in vivo models, promises to assist with better understanding the molecular mechanisms of chemoresistance and the associated enhancement of migration and invasion.

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

The aim of the present study was to investigate the expression of ribosome assembly factor partner of NOB1 homolog (PNO1) and its association with the progression of breast cancer (BC) in patients, as well as its biological function and underlying mechanism of action in BC cells. Bioinformatics and immunohistochemical analyses revealed that PNO1 expression was significantly increased in BC tissues and its high mRNA expression was associated with shorter overall survival (OS) and relapse-free survival (RFS) of patients with BC, as well as multiple clinical characteristics (including advanced stage of NPI and SBR, etc.) of patients with BC. Biological functional studies revealed that transduction of lentivirus encoding sh-PNO1 significantly downregulated PNO1 expression, reduced cell confluency and the number of BC cells in vitro and inhibited tumor growth in vivo. Moreover, PNO1 knockdown decreased the cell viability and arrested cell cycle progression at the G2/M phase, as well as downregulated cyclin B1 (CCNB1) and cyclin-dependent kinase 1 (CDK1) protein expression in BC cells. Correlation analysis demonstrated that PNO1 expression was positively correlated with both CDK1 and CCNB1 expression in BC samples. Collectively, PNO1 was upregulated in BC and associated with BC patient survival, and PNO1 knockdown suppressed tumor growth in vitro and in vivo. In addition, positive regulation of CCNB1 and CDK1 may be one of the underlying mechanisms.

Block of Proliferation 1 Promotes Proliferation, Invasion and Epithelial Mesenchymal Transformation in Gastric Cancer

Background

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide nowadays. Block of proliferation 1 (BOP1), a nucleolar protein involved in rRNA processing and ribosome assembly, is associated with tumor development in certain cancers of digestive system. Therefore, we hypothesized that BOP1 might play an important role in gastric cancer development.

Methods

Gene Expression Omnibus (GEO) database and The Cancer Genome Atlas (TCGA) were used to identify the differentially expressed genes and their clinical relevance. qPCR and western blot were performed further to examine the levels of BOP1 mRNA and protein, respectively. Cell viability, apoptosis, migration and invasion were investigated in gastric cancer cell lines with BOP1 silencing or overexpression. The epithelial mesenchymal transition (EMT) associated proteins, including E-cadherin and N-cadherin, were measured using immunoblotting. Finally, the downstream pathway of BOP1 were explored using bioinformatic analysis and qPCR.

Results

BOP1 was found up-regulated in gastric tumor tissues compared with paired normal tissues (P < 0.0001). Its expression was associated with more advanced pathological grades (P = 0.0006) and tumor location (P = 0.002), as well as a poor survival (HR 1.27, P = 0.015). BOP1 expression was increased in 4 kind of tumor cell lines compared with the normal group. The overexpression of BOP1 promoted cell proliferation and inhibit cell apoptosis, while silencing BOP1 showed a reversed trend. Immunoblotting results suggested that BOP enhanced N-cadherin, a mesenchymal marker, while reduced E-cadherin, an epithelial marker. Finally, bioinformatic prediction showed that the cell cycle could be a downstream pathway of BOP1.

Conclusions

The present study demonstrated that BOP1 contributed to the development of gastric cancer by promoting proliferation, invasion and epithelial mesenchymal transformation, which could be a biomarker or therapeutic target in GC.

Down-Regulating HAUS6 Suppresses Cell Proliferation by Activating the p53/p21 Pathway in Colorectal Cancer

Background: HAUS6 participates in microtubule-dependent microtubule amplification, but its role in malignancies including colorectal cancer (CRC) has not been explored. We therefore assessed the potential oncogenic activities of HAUS6 in CRC. Results: HAUS6 mRNA and protein expression is higher in CRC tissues, and high HAUS6 expression is correlated with shorter overall survival in CRC patients. HAUS6 knockdown in CRC cell lines suppressed cell growth in vitro and in vivo by inhibiting cell viability, survival and arresting cell cycle progression at G0/G1, while HAUS6 over-expression increased cell viability. We showed that these effects are dependent on activation of the p53/p21 signalling pathway by reducing p53 and p21 degradation. Moreover, combination of HAUS6 knockdown and 5-FU treatment further enhanced the suppression of cell proliferation of CRC cells by increasing activation of the p53/p21 pathway. Conclusion: Our study highlights a potential oncogenic role for HAUS6 in CRC. Targeting HAUS6 may be a promising novel prognostic marker and chemotherapeutic target for treating CRC patients.

EBF3 reactivation by inhibiting the EGR1/EZH2/HDAC9 complex promotes metastasis via transcriptionally enhancing vimentin in nasopharyngeal carcinoma

Metastasis is the major reason for treatment failure and accounts for cancer-related death in patients with nasopharyngeal carcinoma. However, the genetic alterations and molecular mechanisms that cause nasopharyngeal carcinoma metastasis are elusive. Herein, we performed RNA sequencing in patients with or without metastasis, and found that the early B-cell factor 3 (EBF3) was significantly elevated in the samples with metastasis. Mechanistically, EBF3 promoted metastasis by directly combining with the promoter of Vimentin and transcriptionally upregulating it. In addition, EBF3 was epigenetically silenced by EGR1/EZH2/HDAC9 complexes via sustaining the high level of H3K27-Me3 at its promoter. Clinically, there was a positive correlation between EBF3 and Vimentin in nasopharyngeal carcinoma tissues. Moreover, high expression of EBF3 or Vimentin was correlated with poor overall survival, while the combination of high EBF3 and Vimentin expression was associated with more significant poor prognosis. Therefore, specific agents targeting EBF3 or stabilizing the EGR1/EZH2/HDAC9 complex could be novel therapeutic strategies for cancer metastasis.

Upregulation of SNTB1 correlates with poor prognosis and promotes cell growth by negative regulating PKN2 in colorectal cancer

Background

Colorectal cancer (CRC) is one of the most highly malignant tumors and has a complicated pathogenesis. A preliminary study identified syntrophin beta 1 (SNTB1) as a potential oncogene in CRC. However, the clinical significance, biological function, and underlying mechanisms of SNTB1 in CRC remain largely unknown. Thus, the present study aimed to investigate the role of SNTB1 in CRC.

Methods

The expression profile of SNTB1 in CRC samples was evaluated by database analysis, cDNA array, tissue microarray, quantitative real-time PCR (qPCR), and immunohistochemistry. SNTB1 expression in human CRC cells was silenced using short hairpin RNAs (shRNA)/small interfering RNAs (siRNA) and its mRNA and protein levels were assessed by qPCR and/or western blotting. Cell viability, survival, cell cycle, and apoptosis were determined by the CCK-8 assay, colony formation, and flow cytometry assays, respectively. A xenograft nude mouse model of CRC was established to validate the roles of SNTB1 in vivo. Immunohistochemistry and TUNEL staining were used to determine the expression of SNTB1, PCNA, and cell apoptosis in tissue samples. Isobaric tag for relative and absolute quantification (iTRAQ) was used to analyze the differentially expressed proteins after knockdown of SNTB1 in CRC cells. Silence of protein kinase N2 (PKN2) using si-PNK2 was performed for rescue experiments.

Results

SNTB1 expression was increased in CRC tissues compared with adjacent noncancerous tissues and the increased SNTB1 expression was associated with shorter overall survival of CRC patients. Silencing of SNTB1 suppressed cell viability and survival, induced cell cycle arrest and apoptosis in vitro, and inhibited the growth of CRC cells in vivo. Further elucidation of the regulation of STNB1 on CRC growth by iTRAQ analysis identified 210 up-regulated and 55 down-regulated proteins in CRC cells after SNTB knockdown. A PPI network analysis identified PKN2 as a hub protein and was up-regulated in CRC cells after SNTB1 knockdown. Western-blot analysis further confirmed that SNTB1 knockdown significantly up-regulated PKN2 protein expression in CRC cells and decreased the phosphorylation of both ERK1/2 and AKT. Moreover, rescue experiments indicated that PKN2 knockdown significantly rescued SNTB1 knockdown-mediated decrease in cell viability, survival, and increase of cell cycle arrest at G0/G1 phase and apoptosis of CRC cells.

Conclusions

These findings indicate that SNTB1 is overexpressed in CRC. Elevated SNTB1 levels are correlated with shorter patient survival. Importantly, SNTB1 promotes tumor growth and progression of CRC, possibly by reducing the expression of PKN2 and activating the ERK and AKT signaling pathway. Our study highlights the potential of SNTB1 as a new prognostic factor and therapeutic target for CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02246-7.

Scouting for common genes in the heterogenous hypoxic tumor microenvironment and their validation in glioblastoma

Investigating the therapeutic and prognostic potential of genes in the heterogeneous hypoxic niche of glioblastoma. We have analyzed RNA expression of U87MG cells cultured in hypoxia compared to normoxia. Common differentially expressed genes (DEGs) from GSE45301 and GSE18494 and their functional enrichment was performed using MetaScape and PANTHER. Hub genes and their ontology were identified using MCode cytoHubba and ClueGO and validated with GlioVis, Oncomine, HPA and PrognoScan. Using the GEO2R analysis of GSE45301 and GSE18494 datasets, we have found a total of 246 common DEGs (180 upregulated and 66 downregulated) and identified 2 significant modules involved in ribosome biogenesis and TNF signaling. Meta-analysis of key genes of each module in cytoHubba identified 17 hub genes (ATF3, BYSL, DUSP1, EGFR, JUN, ETS1, LYAR, NIP7, NOLC1, NOP2, NOP56, PNO1, RRS1, TNFAIP3, TNFRSF1B, UTP15, VEGFA). Of the 17 hub genes, ATF3, BYSL, EGFR, JUN, NIP7, NOLC1, PNO1, RRS1, TNFAIP3 and VEGFA were identified as hypoxia signatures associated with poor prognosis in Glioma. Ribosome biogenesis emerged as a vital contender of possible therapeutic potential with BYSL, NIP7, NOLC1, PNO1 and RRS1 showing prognostic value.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02987-2.

LncRNA CASC21 induces HGH1 to mediate colorectal cancer cell proliferation, migration, EMT and stemness

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs) have been increasingly reported to serve vital parts in malignancies including CRC. Although cancer susceptibility 21 (CASC21) has been uncovered to play a part in CRC, its mechanism still needs further explanation. Thus, our study aimed to further explore the influence and mechanism of CASC21 in CRC progression. Quantitative real-time RT-PCR and western blot were performed to detect gene expression; a series of functional assays were performed to investigate the effect of CASC21 on CRC cells; in vivo tumour growth was evaluated via the nude mice xenograft model. The results revealed that CASC21 facilitated CRC cell proliferation, migration, epithelial-mesenchymal transition (EMT) and stemness. In addition, CASC21 was co-expressed with and bound to transcription factor POU5F1B (POU class 5 homeobox 1B). CASC21 recruited POU5F1B to HGH1 promoter to activate the transcription of HGH1 homolog. Also, CASC21 served as a competitive endogenous RNA (ceRNA) to up-regulate HGH1 via endogenously sponging miR-485-5p. Moreover, HGH1 overexpression counteracted the suppression of CASC21 deficiency on CRC tumour growth. In summary, our study indicated that CASC21 enhanced the expression of HGH1 to promote the malignancy of CRC by recruiting POU5F1B and sponging miR-485-5p, suggesting a key role of CASC21 in CRC progression.

Early B-cell factors involve in the tumorigenesis and predict the overall survival of gastric cancer

Gastric cancer (GC) is a heavy health burden around the world, which is the fifth most frequent tumor and leads to the third most common cancer-related deaths. It is urgent to identify prognostic markers as the guideline for personalized treatment and follow-up. We accessed the prognostic value of Early B-cell factors (EBFs) in GC. A total of 415 GC tissues and 34 normal tissues from The Cancer Genome Atlas Stomach Adenocarcinoma (TCGA-STAD) cohort, 616 external patients from GSE15459, GSE22377, GSE51105, GSE62245 were enrolled for analysis. Univariate and multivariate Cox regression analyses were employed to evaluate the sole and integrative prognostic value of EBFs, respectively. Genetic alterations, DNA methylation of EBFs were also evaluated, as well as the involved signaling pathways. We revealed that increased EBFs associated with the poor prognosis of GC patients, the prognostic model was established in TCGA-STAD cohort, and validated in Gene Expression Omnibus (GEO) cohorts, with effectiveness in both HER2 positive and negative patients. DNA methylation was involved in the impact on prognosis. Cell cycle, immune-associated, and MAPK pathways were influenced by EBFs. Anti-CTLA4 immunotherapy is more suitable for EBFs determining high-risk groups, but not anti-PD-1/PD-L1 therapy. 5-Fluorouracil, methotrexate, vorinostat are suitable to inhibit the function of EBFs. Our new findings provide novel insight into the prediction of prognosis and clinical treatment of GC patients based on EBFs.

Contribution of Energy Dysfunction to Impaired Protein Translation in Neurodegenerative Diseases

Impaired energy homeostasis and aberrant translational control have independently been implicated in the pathogenesis of neurodegenerative diseases. AMP kinase (AMPK), regulated by the ratio of cellular AMP and ATP, is a major gatekeeper for cellular energy homeostasis. Abnormal regulation of AMPK has been reported in several neurodegenerative diseases, including Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS). Most importantly, AMPK activation is known to suppress the translational machinery by inhibiting the mechanistic target of rapamycin complex 1 (mTORC1), activating translational regulators, and phosphorylating nuclear transporter factors. In this review, we describe recent findings on the emerging role of protein translation impairment caused by energy dysregulation in neurodegenerative diseases.

Targeting NUFIP1 Suppresses Growth and Induces Senescence of Colorectal Cancer Cells

NUFIP1 is an RNA-binding protein that interacts with fragile X mental retardation protein (FMRP) in the messenger ribonucleoprotein particle (mRNP). We previously showed that NUFIP1 was upregulated in colorectal cancer (CRC), but how the protein may contribute to the disease and patient prognosis is unknown. Here we combine database analysis, microarray, quantitative PCR, and immunohistochemistry of patients' samples to confirm our previous findings on NUFIP1 overexpression in CRC, and to reveal that increased expression of NUFIP1 in CRC tissues correlated with worse overall, recurrence-free, event-free and disease-free survival in patients, as well as with more advanced CRC clinicopathological stage. Loss of function analysis demonstrated that NUFIP1 knockdown suppressed cell growth in vitro and in vivo, inhibited cell viability and survival, and induced cell cycle arrest and apoptosis in vitro, as well as up-regulated Bax and down-regulated Bcl-2 protein expression. In addition, as a natural anticancer triterpene from various fruits and vegetables, ursolic acid (UA) treatment suppressed cell proliferation, down-regulated NUFIP1 protein expression, and further enhanced the effects of NUFIP1 knockdown in CRC cells in vitro. NUFIP1 knockdown up-regulated the expression of 136 proteins, down-regulated the expression of 41 proteins, and enriched multiple signaling pathways including the senescence-associated heterochromatin foci (SAHF) pathway. Furthermore, NUFIP1 knockdown enhanced the expression of senescence-associated-β-galactosidase (SA-β-gal), the SAHF markers HP1γ and trimethylation (H3k9me3), and the senescence-related protein HMGA2, as well as both p53 and its downstream p21 protein expression. Our findings suggest that NUFIP1 is overexpressed in CRC and correlates with disease progression and poor patient survival. NUFIP1 may exert oncogenic effects partly by altering senescence. UA may show potential to treat CRC by down-regulating NUFIP1.

Long noncoding RNA IL6-AS1 is highly expressed in chronic obstructive pulmonary disease and is associated with interleukin 6 by targeting miR-149-5p and early B-cell factor 1

Chronic obstructive pulmonary disease is a complex condition with multiple etiologies, including inflammation. We identified a novel long noncoding RNA (lncRNA), interleukin 6 antisense RNA 1 (IL6-AS1), which is upregulated in this disease and is associated with airway inflammation. We found that IL6-AS1 promotes the expression of inflammatory factors, especially interleukin (IL) 6. Mechanistically, cytoplasmic IL6-AS1 acts as an endogenous sponge by competitively binding to the microRNA miR-149-5p to stabilize IL-6 mRNA. Nuclear IL6-AS1 promotes IL-6 transcription by recruiting early B-cell factor 1 to the IL-6 promoter, which increases the methylation of the H3K4 histone and acetylation of the H3K27 histone. We propose a model of lncRNA expression in both the nucleus and cytoplasm that exerts similar effects through differing mechanisms, and IL6-AS1 probably increases inflammation via multiple pathways.

PNO1 regulates autophagy and apoptosis of hepatocellular carcinoma via the MAPK signaling pathway

Some studies have reported that activated ribosomes are positively associated with malignant tumors, especially in hepatocellular carcinoma (HCC). The RNA-binding protein PNO1 is a critical ribosome rarely reported in human tumors. This study aimed to explore the molecular mechanisms of PNO1 in HCC. Using 150 formalin-fixed and paraffin-embedded samples and 8 fresh samples, we found high PNO1 expression in HCC tumor tissues through Western blotting and RT-PCR. Moreover, the higher PNO1 expression was associated with poor HCC prognosis patients. In vitro and in vivo experiments indicated that PNO1 overexpression promoted the proliferation and depressed the apoptosis of HCC cells. High PNO1 expression also increased the autophagy of HCC cells. The molecular mechanisms underlying PNO1 were examined by RNA-seq analysis and a series of functional experiments. Results showed that PNO1 promoted HCC progression through the MAPK signaling pathway. Therefore, PNO1 was overexpressed in HCC, promoted autophagy, and inhibited the apoptosis of HCC cells through the MAPK signaling pathway.

Prognostic and immunological roles of Fc fragment of IgG binding protein in colorectal cancer

Valuable diagnostic and prognostic biomarkers are urgently needed for colorectal cancer (CRC), which is one of the leading causes of mortality worldwide. Previous studies have reported altered expression of a mucin-like protein Fc fragment of IgG binding protein (FCGBP) in various types of cancer, but its potential diagnostic, prognostic and immunological roles in CRC remain to be determined. Therefore, the aim of current study was to investigate the potential roles of FCGBP in CRC. The present study investigated FCGBP mutations and changes in its expression levels using a combination of microarray and public dataset analyses, as well as immunohistochemistry. The results demonstrated a 10.5% mutation frequency in the FCGBP coding sequence in CRC tissues, and identified decreased FCGBP mRNA or protein expression levels in colorectal adenoma and CRC (compared with those in normal colorectal tissues from healthy control subjects), including pathologically advanced CRC (stage III+IV vs. I+II). Survival analysis using the GEPIA and Kaplan-Meier Plotter databases revealed that low FCGBP expression levels were associated with short overall, disease-free, relapse-free and event-free survival times in patients with CRC. Notably, analysis using the online Tumor IMmune Estimation Resource database revealed a positive correlation between FCGBP expression levels and the extent of infiltrating immune cells, such as B cells and dendritic cells. Consistently, the expression levels of most markers (51/57) for various types of immune cells were significantly correlated with FCGBP expression levels in CRC tissues. These findings suggested that FCGBP may serve as a diagnostic and prognostic biomarker, and that FCGBP may be associated with immune infiltration in CRC.

Knockdown of PNO1 inhibits esophageal cancer progression

The present study aimed to investigate the role of partner of NOB1 homolog (PNO1) in esophageal cancer (EC). The expression levels of PNO1 in EC were primarily analyzed using data obtained from databases. PNO1 expression was also knocked down in EC cells (Eca-109 and TE1) to determine the biological effects of PNO1 on tumorigenesis in vitro and in vivo. In addition, possible downstream targets of PNO1 in EC were identified. The expression levels of PNO1 were upregulated in the tumor tissues compared with that noted in normal tissues. Moreover, the knockdown (KD) of PNO1 suppressed cell proliferation, migration and invasion, and promoted cell apoptosis (P<0.05). Furthermore, the protein expression levels of AKT1, Twist, Myc, mTOR, matrix metalloproteinase 2 (MMP2), nuclear factor (NF)-κB p65 and β-catenin 1 (CTNNB1) were downregulated following the KD of PNO1 in Eca-109 cells (P<0.05). In addition, the overexpression of CTNNB1 reversed the effects of PNO1 KD in Eca-109 cells (P<0.05). In conclusion, the findings of the present study suggest that PNO1 promotes EC progression by regulating AKT1, Twist, Myc, mTOR, MMP2, NF-κB p65 and CTNNB1 expression.

A panel of eight mRNA signatures improves prognosis prediction of osteosarcoma patients

Genetic alterations are vital to the progression of osteosarcoma carcinoma. The present study investigated a panel of gene signatures that could evaluate prognosis in osteosarcoma based on data from the Therapeutically Applicable Research To Generate Effective Treatments initiative. Osteosarcoma messenger RNA (mRNA) profiles and clinical data were downloaded from the therapeutically applicable research to generate effective treatments database. Patients with osteosarcoma were divided into two groups based on findings at diagnosis: with and without metastasis. Differentially expressed mRNAs were compared and analyzed between groups. Univariate and multivariate Cox regression analyses identified a set of eight mRNAs with the ability to classify patients into high-risk and low-risk groups with significantly different overall survival times. Further analysis indicated that the eight-mRNA signature was an independent prognostic factor after adjusting for other clinical factors. Receiver operating characteristic curve analysis demonstrated a good performance of the eight-mRNA signature. Further, the biological processes and signaling pathways of the eight-mRNA signature were reviewed using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes resources. Finally, the results of the TCGA analysis were verified by other cohorts from Gene Expression Omnibus database. The identification of an eight-mRNA signature not only provides a prognostic biomarker of osteosarcoma but also offers the potential of novel therapeutic targets for its treatment.

MYC-mediated upregulation of PNO1 promotes glioma tumorigenesis by activating THBS1/FAK/Akt signaling

PNO1 has been reported to be involved in tumorigenesis, however, its role in glioma remains unexplored. In the present study, PNO1 expression in glioma from on-line databases, cDNA, and tissue microarrays was upregulated and associated with poor prognosis. PNO1 knockdown inhibits tumor cell growth and invasion both in vitro and in vivo; whereas PNO1 overexpression promoted cell proliferation and invasion in vitro. Notably, PNO1 interacted with THBS1 and the promotion of glioma by PNO1 overexpression could be attenuated or even reversed by simultaneously silencing THBS1. Functionally, PNO1 was involved in activation of FAK/Akt pathway. Moreover, overexpressing MYC increased PNO1 promoter activity. MYC knockdown decreased PNO1 and THBS1 expression, while inhibited cell proliferation and invasion. In conclusion, MYC-mediated upregulation of PNO1 contributes to glioma progression by activating THBS1/FAK/Akt signaling. PNO1 was reported to be a tumor promotor in the development and progression of glioma and may act as a candidate of therapeutic target in glioma treatment.

TAF1A and ZBTB41 serve as novel key genes in cervical cancer identified by integrated approaches

Cervical cancer (CC) is the second most common cancer and the leading cause of cancer mortality in women. Numerous studies have found that the development of CC was associated with multiple genes. However, the mechanisms on gene level are enigmatic, hindering the understanding of its functional roles. This study sought to identify prognostic biomarkers of CC, and explore their biological functions. Here we conducted an integrated analysis to screen potential vital genes. Candidate genes were further tested by experiments in clinical specimens and cancer cell line. Then, molecular modeling was used to predict the three-dimensional structure of candidate genes’ proteins, and the interaction pattern was analyzed by docking simulation technique. Among the potential genes identified, we found that TAF1A and ZBTB41 were highly correlated. Furthermore, there was a definite interaction between the proteins of TAF1A and ZBTB41, which was affected by the activity of the p53 signaling pathway. In conclusion, our findings identified TAF1A and ZBTB41 could serve as biomarkers of CC. We confirmed their biological function and deciphered their interaction for the first time, which may be helpful for developing further researches.

Ribosome assembly factor URB1 contributes to colorectal cancer proliferation through transcriptional activation of ATF4

Ribosome assembly factor URB1 is essential for ribosome biogenesis. However, its latent role in cancer remains unclear. Analysis of The Cancer Genome Atlas database and clinical tissue microarray staining showed that URB1 expression was upregulated in colorectal cancer (CRC) and prominently related to clinicopathological characteristics. Silencing of URB1 hampered human CRC cell proliferation and growth in vitro and in vivo. Microarray screening, ingenuity pathway analysis, and JASPAR assessment indicated that activating transcription factor 4 (ATF4) and X‐box binding protein 1 (XBP1) are potential downstream targets of URB1 and could transcriptionally interact through direct binding. Silencing of URB1 significantly decreased ATF4 and cyclin A2 (CCNA2) expression in vivo and in vitro. Restoration of ATF4 effectively reversed the malignant proliferation phenotype of URB1‐silenced CRC cells. Dual‐luciferase reporter and ChIP assays indicated that XBP1 transcriptionally activated ATF4 by binding with its promoter region. X‐box binding protein 1 colocalized with ATF4 in the nuclei of RKO cells, and ATF4 mRNA expression was positively regulated by XBP1. This study shows that URB1 contributes to oncogenesis and CRC growth through XBP1‐mediated transcriptional activation of ATF4. Therefore, URB1 could be a potential therapeutic target for CRC.

APOE4 exacerbates synapse loss and neurodegeneration in Alzheimer's disease patient iPSC-derived cerebral organoids

APOE4 is the strongest genetic risk factor associated with late-onset Alzheimer’s disease (AD). To address the underlying mechanism, we develop cerebral organoid models using induced pluripotent stem cells (iPSCs) with APOE ε3/ε3 or ε4/ε4 genotype from individuals with either normal cognition or AD dementia. Cerebral organoids from AD patients carrying APOE ε4/ε4 show greater apoptosis and decreased synaptic integrity. While AD patient-derived cerebral organoids have increased levels of Aβ and phosphorylated tau compared to healthy subject-derived cerebral organoids, APOE4 exacerbates tau pathology in both healthy subject-derived and AD patient-derived organoids. Transcriptomics analysis by RNA-sequencing reveals that cerebral organoids from AD patients are associated with an enhancement of stress granules and disrupted RNA metabolism. Importantly, isogenic conversion of APOE4 to APOE3 attenuates the APOE4-related phenotypes in cerebral organoids from AD patients. Together, our study using human iPSC-organoids recapitulates APOE4-related phenotypes and suggests APOE4-related degenerative pathways contributing to AD pathogenesis.

APOE4 is a strong genetic risk factor for late-onset Alzheimer’s disease. Here, the authors show that APOE4 is associated with AD features in hiPSCs-derived cerebral organoids. Isogenic conversion of APOE4 to APOE3 attenuates the AD-associated phenotype.

Ribosome Biogenesis Alterations in Colorectal Cancer

Many studies have focused on understanding the regulation and functions of aberrant protein synthesis in colorectal cancer (CRC), leaving the ribosome, its main effector, relatively underappreciated in CRC. The production of functional ribosomes is initiated in the nucleolus, requires coordinated ribosomal RNA (rRNA) processing and ribosomal protein (RP) assembly, and is frequently hyperactivated to support the needs in protein synthesis essential to withstand unremitting cancer cell growth. This elevated ribosome production in cancer cells includes a strong alteration of ribosome biogenesis homeostasis that represents one of the hallmarks of cancer cells. None of the ribosome production steps escape this cancer-specific dysregulation. This review summarizes the early and late steps of ribosome biogenesis dysregulations described in CRC cell lines, intestinal organoids, CRC stem cells and mouse models, and their possible clinical implications. We highlight how this cancer-related ribosome biogenesis, both at quantitative and qualitative levels, can lead to the synthesis of ribosomes favoring the translation of mRNAs encoding hyperproliferative and survival factors. We also discuss whether cancer-related ribosome biogenesis is a mere consequence of cancer progression or is a causal factor in CRC, and how altered ribosome biogenesis pathways can represent effective targets to kill CRC cells. The association between exacerbated CRC cell growth and alteration of specific steps of ribosome biogenesis is highlighted as a key driver of tumorigenesis, providing promising perspectives for the implementation of predictive biomarkers and the development of new therapeutic drugs.

The molecular mechanisms of celecoxib in tumor development

BACKGROUND

Clinical studies have shown that celecoxib can significantly inhibit the development of tumors, and basic experiments and in vitro experiments also provide a certain basis, but it is not clear how celecoxib inhibits tumor development in detail.

METHODS

A literature search of all major academic databases was conducted (PubMed, China National Knowledge Internet (CNKI), Wan-fang, China Science and Technology Journal Database (VIP), including the main research on the mechanisms of celecoxib on tumors.

RESULTS

Celecoxib can intervene in tumor development and reduce the formation of drug resistance through multiple molecular mechanisms.

CONCLUSION

Celecoxib mainly regulates the proliferation, migration, and invasion of tumor cells by inhibiting the cyclooxygenases-2/prostaglandin E2 signal axis and thereby inhibiting the phosphorylation of nuclear factor-κ-gene binding, Akt, signal transducer and activator of transcription and the expression of matrix metalloproteinase 2 and matrix metalloproteinase 9. Meanwhile, it was found that celecoxib could promote the apoptosis of tumor cells by enhancing mitochondrial oxidation, activating mitochondrial apoptosis process, promoting endoplasmic reticulum stress process, and autophagy. Celecoxib can also reduce the occurrence of drug resistance by increasing the sensitivity of cancer cells to chemotherapy drugs.

HAX1 enhances the survival and metastasis of non-small cell lung cancer through the AKT/mTOR and MDM2/p53 signaling pathway

Background

HS‐1‐associated protein‐1 (HAX1) has been reported to be overexpressed in non‐small cell lung cancer (NSCLC) tissues. However, the underlying mechanism of HAX1 in NSCLC has not previously been demonstrated. The present study investigated the role and underlying mechanism of HAX1 in NSCLC.

Methods

The HAX1 expression were confirmed in NSCLC tissues through TCGA database and qRT‐PCR. Moreover, we performed qRT‐PCR, Western blotting, Transwell assays, TUNEL assays and so on to evaluate the role of HAX1 in A549 and H1299 cell lines.

Results

mRNA expression of HAX1 was overexpressed in NSCLC tissues compared to adjacent normal tissues according to The Cancer Genome Atlas (TCGA) database. QRT‐PCR assays showed that HAX1 mRNA expression was upregulated in NSCLC tissues. The high HAX1 mRNA levels were found to be positively associated with tumor size, TNM stage and lymphatic metastasis. Silencing of HAX1 promoted apoptosis and reduced invasion of A549 and H1299 cells by inhibiting the AKT/mTOR and MDM2/P53 signal pathway. AKT agonist SC79 could inhibit apoptosis and promote proliferation, migration and invasion of A549 and H1299 cells transfected with si‐HAX1.

Conclusions

The present study provided a better understanding of HAX1 mechanism in NSCLC and potential therapeutic target for NSCLC.

Death-associated protein kinase 1 suppresses hepatocellular carcinoma cell migration and invasion by upregulation of DEAD-box helicase 20

Death-associated protein kinase 1 (DAPK) is a calcium/calmodulin kinase that plays a vital role as a suppressor gene in various cancers. Yet its role and target gene independent of p53 is still unknown in hepatocellular carcinoma (HCC). In this study, we discovered that DAPK suppressed HCC cell migration and invasion instead of proliferation or colony formation. Using a proteomics approach, we identified DEAD-box helicase 20 (DDX20) as an important downstream target of DAPK in HCC cells and critical for DAPK-mediated inhibition of HCC cell migration and invasion. Using integrin inhibitor RGD and GTPase activity assays, we discovered that DDX20 suppressed HCC cell migration and invasion through the CDC42-integrin pathway, which was previously reported as an important downstream pathway of DAPK in cancer. Further research using cycloheximide found that DAPK attenuates the proteasomal degradation of DDX20 protein, which is dependent on the kinase activity of DAPK. Our results shed light on new functions and regulation for both DAPK and DDX20 in carcinogenesis and identifies new potential therapeutic targets for HCC.

Transcription Factor EBF1 Over-Expression Suppresses Tumor Growth in vivo and in vitro via Modulation of the PNO1/p53 Pathway in Colorectal Cancer

Early B cell factor 1 (EBF1) has been identified as an upstream transcription factor of the potential oncogene PNO1 and is involved in the growth of colorectal cancer (CRC) cells. However, its expression, biological function, and underlying mechanism of action in most solid tumors remain largely unknown. We postulated that EBF1 has a role in the pathophysiology of CRC. Analysis of EBF1 mRNA expression in CRC tumor samples from several public databases and directly from banked tissues revealed that EBF1 mRNA expression is lower in CRC tissue compared to non-cancerous colorectal tissue. Survival analysis of multiple datasets revealed that low EBF1 expression was correlated with shorter overall survival, relapse-free survival, and event-free survival in CRC patients. Transduction of lentivirus encoding full length EBF1 followed by in vitro and in vivo assays demonstrated that EBF1 over-expression in CRC cell lines suppresses cell growth by inhibiting cell viability, cell survival, and induces cell cycle arrest and apoptosis. Mechanistic investigation indicated that EBF1 over-expression down-regulates PNO1 mRNA and protein expression, as well as transcriptional activity while up-regulating the expression of p53 and p21 proteins. These findings suggest that EBF1 is a novel potential tumor suppressor in CRC with prognostic value for the identification of patients at high-risk of relapse.

PNO1, which is negatively regulated by miR-340-5p, promotes lung adenocarcinoma progression through Notch signaling pathway

Many studies have shown that the hyperactivation of ribosome biogenesis plays essential roles in the initiation and progression of cancers. As a ribosome assembly factor, PNO1 plays an important role in ribosome biogenesis. However, little is known about the expression and function of PNO1 in human tumors. In our present study, we aimed to explore the functional roles and the underlying molecular mechanisms of PNO1 in human lung adenocarcinoma (LUAD). Both bioinformatics databases and tumor tissues demonstrated that the expression of PNO1 in LUAD tissues was higher than that in adjacent tissues and predicted poor survival in LUAD patients. In vitro and in vivo assays suggested that downregulation of PNO1 expression suppressed LUAD cell proliferation and invasion. Further studies found that miR-340-5p depressed PNO1 expression via direct binding to the 3′ untranslated region (UTR) of PNO1. PNO1 expression was negatively correlated with miR-340-5p expression in LUAD cells and tissue samples. Moreover, upregulation or downregulation of miR-340-5p expression reversed the effects of PNO1 inhibition and overexpression, respectively. Meanwhile, downregulation of PNO1 inhibited Notch signaling pathway which modulated epithelial mesenchymal transition (EMT). These results indicate that PNO1, negatively regulated by miR-340-5p, played an important role in LUAD progression via Notch signaling pathway. The miR-340-5p/PNO1/Notch axis might be a potential target for individualized and precise treatment of LUAD patients in the future.