Down-regulation of TRAF4 targeting RSK4 inhibits proliferation, invasion and metastasis in breast cancer xenografts

Expression of RSK4 protein in non-small cell lung cancer tissues, adjacent tissues and its correlation with clinicopathological features

OBJECTIVE

To evaluate the expression of Ribosomal S6 kinase 4 (RSK4) protein in non-small cell lung cancer (NSCLC) tissues and adjacent non-tumor tissues, and to elucidate its correlation with clinicopathological features of NSCLC.

METHODS

We analyzed 100 NSCLC patients treated at the Second Affiliated Hospital of Zhejiang University School of Medicine from June 2020 to June 2022. Patient demographics and clinical data, including gender, age, history of diabetes, tumor location, degree of tumor differentiation, lymph node metastasis, and clinical stage, were collected. RSK4 protein expression was assessed in tissue samples via immunohistochemical staining.

RESULTS

RSK4 protein was positively expressed in 35.00% of cancerous tissues, significantly lower than the 69.00% observed in adjacent non-tumor tissues (P < 0.05). Patients with lower tumor differentiation, advanced Tumor Node Metastasis (TNM) stages, and lymph node metastases showed significantly reduced RSK4 expression compared to those with higher differentiation, earlier TNM stages, and no lymph node metastases (all P < 0.05). Cox regression analysis indicated that TNM stage, low differentiation, and lymph node metastases significantly influenced RSK4 expression (all P < 0.05). Survival analysis revealed a higher positive prognosis survival rate of 74.29% (26/35) among patients with positive RSK4 expression, versus 53.85% (35/65) in those with negative expression (P < 0.05). Spearman correlation analysis demonstrated a significant positive correlation of RSK4 expression with TNM stage, lymph node metastasis, and patient prognosis (all P < 0.05).

CONCLUSION

Positive RSK4 expression in NSCLC tissues is significantly correlated with advanced cancer stage, poor differentiation, and presence of lymph node metastasis, suggesting a potential tumor suppressor role for RSK4 in NSCLC. This association underscores its prognostic relevance in NSCLC patients.

Circular RNAs in the chemoresistance of triple-negative breast cancer: A systematic review

This study aims to assess studies on circular RNAs (circRNAs) in the chemoresistance of triple-negative breast cancer (TNBC) and provide relevant references for the development of new TNBC chemotherapy sensitivity biomarkers and therapeutic targets. The PubMed, Embase, Web of Knowledge, Cochrane Library, and four Chinese databases were searched up to January 27, 2023, and studies related to TNBC chemoresistance were included. The basic characteristics of the studies and the mechanisms of circRNAs in regulating TNBC chemoresistance were analyzed. A total of 28 studies published between 2018 and 2023 were included, and the chemotherapeutics included adriamycin, paclitaxel, docetaxel, 5-fluorouracil, lapatinib, and so forth. A total of 30 circRNAs were identified, 86.67% (n = 26) of these circRNAs were reported to act as microRNA (miRNA) sponges to regulate chemotherapy sensitivity, while only two circRNAs (circRNA-MTO1 and circRNA-CREIT) interacted with proteins. A total of 14, 12, and 2 circRNAs were reported to be associated with chemoresistance to adriamycin, taxanes, and 5-fluorouracil, respectively. Six circRNAs were found to act as miRNA sponges that promote chemotherapy resistance by regulating the PI3K/Akt signalling pathway. CircRNAs participate in the regulation of TNBC chemoresistance and can be used as biomarkers and therapeutic targets for improving chemotherapy sensitivity. However, further studies are needed to confirm the role of circRNAs in TNBC chemoresistance.

Ribosomal S6 kinase 4 (RSK4) tumor suppressor gene promoter methylation status in ovarian cancer

BACKGROUND

Previously, we reported lower RSK4 mRNA and protein levels in malignant ovarian tumors compared to normal and benign ovarian tissues. Also, we observed a significant inverse correlation between the advanced ovarian cancer stages and RSK4 mRNA levels. We did not investigate the mechanisms involved in RSK4-reduced expression in ovarian cancer. Thus, this study investigates whether RSK4 promoter methylation in ovarian cancer tissues is responsible for its low expression. Additionally, the reactivation of RSK4 expression and its effect was studied in ovarian cancer cell lines.

METHODS AND RESULTS

RSK4 promoter methylation percentage in malignant and benign ovarian tumors and normal ovary tissues was determined by combined bisulfite restriction analysis. The reactivation of RSK4 expression by decitabine treatment was studied in OVCAR3, SKOV3, TOV-112D, and TOV-21G cells by Western blotting. Cell proliferation was determined by XTT. A significantly high methylation percentage of the RSK4 promoter was observed among malignant and benign ovarian tumors but not in normal ovarian tissue. RSK4 promoter methylation was not associated with age, histological subtype, or stages of ovarian cancer. RSK4 promoter methylation correlates weakly but not significantly with RSK4 protein expression. No correlation was shown between RSK4 methylation and RSK4 mRNA expression. Decitabine induces RSK4 reactivation in all cell lines. However, cell proliferation was reduced only in TOV-112D cells.

CONCLUSION

These data indicate that although RSK4 promoter methylation is increased in malignant ovarian tumors, this mechanism is unlikely to regulate its expression in ovarian cancer. RSK4 reactivation reduced cell proliferation only in the endometroid histological subtype.

TRAF6 as a potential target in advanced breast cancer: a systematic review, meta-analysis, and bioinformatics validation

TRAF6 has emerged as a key regulator of breast cancer (BCa). However, the TRAF family constitutes of seven members that exhibit distinct and overlapping functions. To explore which TRAF represents a potential druggable target for BCa treatment, we searched Medline, Web of Science and Scopus for relevant studies from inception to June 27, 2021. We identified 14 in vitro, 11 in vivo and 4 human articles. A meta-analysis of pharmacological studies showed that in vitro inhibition of TRAF2/4 (mean difference (MD): - 57.49, 95% CI: - 66.95, - 48.02, P < 0.00001) or TRAF6 (standard(Std.)MD: - 4.01, 95% CI: - 5.75, - 2.27, P < 0.00001) is associated with reduction in BCa cell migration. Consistently, inhibition of TRAF2/4 (MD: - 51.08, 95% CI: - 64.23, - 37.94, P < 0.00001) and TRAF6 (Std.MD: - 2.80, 95% CI: - 4.26, - 1.34, P = 0.0002) is associated with reduced BCa cell invasion, whereas TRAF2/4 inhibition (MD: - 40.54, 95% CI: - 52.83, - 28.26, P < 0.00001) is associated with reduced BCa cell adhesion. Interestingly, only inhibition of TRAF6 (MD: - 21.46, 95% CI: - 30.40, - 12.51, P < 0.00001) is associated with reduced cell growth. In animal models of BCa, administration of pharmacological inhibitors of TRAF2/4 (Std.MD: - 3.36, 95% CI: - 4.53, - 2.18, P < 0.00001) or TRAF6 (Std.MD: - 4.15, 95% CI: - 6.06, - 2.24, P < 0.0001) in mice is associated with reduction in tumour burden. In contrast, TRAF6 inhibitors (MD: - 2.42, 95% CI: - 3.70, - 1.14, P = 0.0002) reduced BCa metastasis. In BCa patients, high expression of TRAF6 (Hazard Ratio: 1.01, CI: 1.01, 1.01, P < 0.00001) is associated with poor survival rate. Bioinformatics validation of clinical and pathway and process enrichment analysis in BCa patients confirmed that gain/amplification of TRAF6 is associated with secondary BCa in bone (P = 0.0079), and poor survival rate (P < 0.05). Overall, TRAF6 inhibitors show promise in the treatment of metastatic BCa. However, low study number and scarcity of evidence from animal and human studies may limit the translation of present findings into clinical practice.

The role of long non-coding RNA HCG18 in cancer

The incidence of cancer is increasing worldwide and is becoming the most common cause of death. Identifying new biomarkers for cancer diagnosis and prognosis is important for developing cancer treatment strategies and reducing mortality. Long non-coding RNAs (lncRNAs) are non-coding, single-stranded RNAs that play an important role as oncogenes or tumor suppressors in the occurrence and development of human tumors. Abnormal expression of human leukocyte antigen complex group 18 (HCG18) is observed in many types of cancer, and its imbalance is closely related to cancer progression. HCG18 regulates cell proliferation, invasion, metastasis, and anti-apoptosis through a variety of mechanisms. Therefore, HCG18 is a potential tumor biomarker and therapeutic target. However, the therapeutic significance of HCG18 has not been well studied, and future research may develop new intervention strategies to combat cancer. In this study, we reviewed the biological function, mechanism, and potential clinical significance of HCG18 in various cancers to provide a reference for future research.

TRAF4-mediated ubiquitination-dependent activation of JNK/Bcl-xL drives radioresistance

The E3 ligase TNF receptor-associated factor 4 (TRAF4) is upregulated and closely associated with tumorigenesis and the progression of multiple human malignancies. However, its effect on radiosensitivity in colorectal cancer (CRC) has not been elucidated. The present study found that TRAF4 was significantly increased in CRC clinical tumor samples. Depletion of TRAF4 impaired the malignant phenotype of CRC cells and sensitized irradiation-induced cell death. Irradiation activated the c-Jun N-terminal kinases (JNKs)/c-Jun signaling via increasing JNKs K63-linked ubiquitination and phosphorylation. Furthermore, c-Jun activation triggered the transcription of the antiapoptotic protein Bcl-xL, thus contributing to the radioresistance of CRC cells. TRAF4 was positively correlated with c-Jun and Bcl-xL, and blocking TRAF4 or inhibiting Bcl-xL with inhibitor markedly promoted ionizing radiation (IR)-induced intrinsic apoptosis and sensitized CRC cells to radiotherapy in vitro and in vivo. Our findings illustrate a potential mechanism of radioresistance, emphasizing the clinical value of targeting the TRAF4/Bcl-xL axis in CRC therapy.

SRC-3/TRAF4 facilitates ovarian cancer development by activating the PI3K/AKT signaling pathway

OBJECTIVE

Ovarian cancer is the seventh most common cancer in women, and it causes many deaths in women worldwide. Patients with ovarian cancer have a poor prognosis and low survival rate. This study aimed to explore the role of the SRC-3/TRAF4/PI3K/AKT pathway in ovarian cancer development.

METHODS

SRC-3 and TRAF4 expression in ovarian cancer cell lines were assessed using qRT-PCR and western-blotting. The expression of SRC-3 and TRAF4 in ovarian cancer cells was downregulated by transient transfection with sh-RNAs. An MTT assay was performed to evaluate cell proliferation. Cell migration and invasion were measured using a Transwell assay. Cell stemness was detected using a cell spheroidization assay and western blotting. The expression levels of stem cell factors and PI3K/AKT pathway proteins were determined by qRT-PCR and western blot analysis.

RESULTS

SRC-3 and TRAF4 were upregulated in ovarian cancer cell lines. TRAF4 is a downstream factor of SRC-3, and the protein level of TRAF4 was regulated by SRC-3. SRC-3 knockdown reduced TRAF4 expression. Silencing SRC-3 or TRAF4 inhibited cell proliferation, migration, and invasion, as well as the expression of stem cell factors. Furthermore, sh-TRAF4 as well as treatment with LY294002, the PI3K/Akt inhibitor, inhibited the phosphorylation of Akt and PI3K, thus repressing the activation of PI3K/AKT signaling pathway in ovarian cancer cell lines. However, TRAF4 overexpression reversed the effect of SRC-3 silencing on cell proliferation, migration, invasion, and stemness.

CONCLUSION

Our study demonstrated that SRC-3/TRAF4 promotes ovarian cancer cell growth, migration, invasion, and stemness by activating the PI3K/AKT pathway.

TRAF4 Inhibits the Apoptosis and Promotes the Proliferation of Breast Cancer Cells by Inhibiting the Ubiquitination of Spindle Assembly-Associated Protein Eg5

Tumor necrosis factor receptor associated factor 4 (TRAF4) is a RING domain E3 ubiquitin ligase that mediates the ubiquitination of various proteins and plays an important role in driving tumor progression. By studying the relationship between TRAF4 and Eg5, a member of the kinesin family that plays a critical role in spindle assembly, we demonstrated that TRAF4 regulated Eg5 ubiquitination and contributed to Eg5-mediated breast cancer proliferation and inhibited breast cancer apoptosis. TRAF4 and Eg5 were both highly expressed in breast cancer and their protein level was positively correlated. Relying on its Zinc fingers domain, TRAF4 interacted with Eg5 in the cytoplasm of breast cancer cells. TRAF4 was a mitosis-related protein, and by up-regulating the protein level of Eg5 TRAF4 participated in spindle assembly. Loss of TRAF4 resulted in monopolar spindles formation, but loss of function could be rescued by Eg5. Relying on its RING domain, TRAF4 up-regulated Eg5 protein levels by inhibition of Eg5 ubiquitination, thus stabilizing Eg5 protein level during mitosis. Furthermore, we found that Smurf2, a TRAF4-targeted ubiquitination substrate, mediated the regulation of Eg5 ubiquitination by TRAF4. TRAF4 inhibited the interaction between Smurf2 and Eg5, and down-regulated the protein level of Smurf2 by promoting its ubiquitination, thereby inhibited the Smurf2-catalyzed ubiquitination of Eg5 and up-regulated Eg5 protein levels. We also demonstrate that TRAF4 plays an important role in promoting cell proliferation and in inhibiting cell apoptosis induced by Eg5. In summary, our study suggests a new direction for investigating the role of TRAF4 in driving breast cancer progression.

The Research Progress in Physiological and Pathological Functions of TRAF4

Tumour necrosis factor receptor-associated factor 4 (TRAF4) is a member of the TRAF protein family, a cytoplasmic bridging molecule closely associated with various immune functions. The physiological processes of TRAF4 are mainly involved in embryonic development, cell polarity, cell proliferation, apoptosis, regulation of reactive oxygen species production. TRAF4 is overexpressed in a variety of tumors and regulates the formation and development of a variety of tumors. In this review, we summarize the physiological and pathological regulatory functions of TRAF4 and focus on understanding the biological processes involved in this gene, to provide a reference for further studies on the role of this gene in tumorigenesis and development.

LncRNA HCG18 upregulates TRAF4/TRAF5 to facilitate proliferation, migration and EMT of epithelial ovarian cancer by targeting miR-29a/b

Background

Although long noncoding RNA HLA complex group 18 (lncRNA HCG18) has been suggested to regulate cell growth in several tumours, the function of HCG18 in epithelial ovarian cancer (EOC) and its mechanism are still unclear.

Methods

shRNAs were applied to reduce HCG18 and related genes. For overexpression of miRNA, a miRNA mimic was transfected into cells. Quantitative real-time PCR (qRT–PCR) was used to detect levels of HCG18, miR-29a/b, and mRNAs. MTT, colony formation, wound healing and Transwell assays were used to evaluate cell proliferation, migration and invasion, respectively. A luciferase reporter assay was utilized to evaluate NF-κB activity and the binding of miRNAs with HCG18 or TRAF4/5. BALB nude mice injected with cells stably expressing shHCG18 or shNC were used for in vivo modelling. Subcutaneous tumour growth was monitored in nude mice, and immunohistochemistry (IHC) was used to determine expression of the proliferation marker Ki67.

Results

Abnormal expression of HCG18 and miR-29a/b was observed in EOC tissues. Knockdown of HCG18 using shRNA inhibited proliferation, migration, EMT and the proinflammatory pathway in EOC cells. miR-29a/b mimics and TRAF4/5 knockdown exhibited effects similar to HCG18 knockdown. Further experiments suggested that HCG18 directly targets miR-29a/b and upregulates TRAF4/5 expression, which are inhibited by targeting miR-29a/b. Moreover, overexpression of TRAF4/5 antagonized the inhibitory effect of HCG18 knockdown, suggesting that they are involved in HCG18-mediated oncogenic effects. Silencing HCG18 reduced tumour size and levels of Ki67 and TRAF4/5 while increasing miR-29a/b levels in vivo.

Conclusions

Taken together, our data revealed an oncogenic signalling pathway mediated by HCG18 in ovarian cell lines, which functions as a ceRNA of miR-29a/b and thus derepresses expression levels of TRAF4/5, facilitating NF-κB pathway-mediated promotion of EOC cell proliferation and migration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00415-y.

ZFPM2-AS1 facilitates cell growth in esophageal squamous cell carcinoma via up-regulating TRAF4

Emerging evidence has confirmed that long noncoding RNAs (lncRNAs) are strongly involved in tumor initiation and development. LncRNA ZFPM2 antisense RNA 1 (ZFPM2-AS1) has been identified as a tumor facilitator in some cancers; nevertheless, its functional significance and regulatory mechanism remain greatly unclear in esophageal squamous cell carcinoma (ESCC). Here, we detected ZFPM2-AS1 expression in ESCC cell lines using qRT-PCR. ZFPM2-AS1 knockdown models were established for investigating the biological function of ZFPM2-AS1 in ESCC cells. The association between miR-3612 and ZFPM2-AS1 or TRAF4 was assessed by RNA pull-down and luciferase reporter assays. The present study indicated that ZFPM2-AS1 was significantly up-regulated in ESCC cells. Functional assays manifested that ZFPM2-AS1 knockdown restrained cell proliferation, migration and invasion, and facilitated cell apoptosis in ESCC. Mechanistically, ZFPM2-AS1 promoted ESCC cell growth and up-regulated TRAF4 to trigger NF-κB pathway by sequestering miR-3612. Besides, miR-3612 was confirmed to be a tumor inhibitor in ESCC. Through restoration experiments, we observed that TRAF4 overexpression could recover the suppressive effect of ZFPM2-AS1 on ESCC cell growth. Collectively, all the results suggested that ZFPM2-AS1 was an oncogene in ESCC cell growth by up-regulating TRAF4 and activating NF-κB pathway.

Prominent roles of ribosomal S6 kinase 4 (RSK4) in cancer

RSK4 refers to one Ser/Thr protein kinase functioning downstream pertaining to the signaling channel of protein kinase (MAPK) stimulated by Ras/mitogen. RSK4 can regulate numerous substrates impacting cells' surviving state, growing processes and proliferating process. Thus, dysregulated RSK4 active state display a relationship to several carcinoma categories, covering breast carcinoma, esophageal squamous cell carcinoma, glioma, colorectal carcinoma, lung carcinoma, ovarian carcinoma, leukemia, endometrial carcinoma, and kidney carcinoma. Whether RSK4 is a tumor suppressor gene or one oncogene remains controversial. No specific inhibiting elements for RSK4 have been found. This review briefs the existing information regarding RSK4 activating process, the function and mechanism of RSK4 in different tumors, and the research progress and limitations of existing RSK inhibitors. RSK4 may be a potential target of molecular therapy medicine in the future.

RSK4: a new prognostic factor in glioma

Glioma is the most common and fatal brain tumour and has a poor prognosis. Ribosomal S6 protein kinase 4 (RSK4) has been found to be involved in multiple tumour types; however, the role of RSK4 in gliomas and its clinical relevance remain unclear. In the present study, RSK4 expression was found to be significantly increased in glioma tissues compared with matched adjunct non-noncancerous tissues. Moreover, the expression of RSK4 was significantly higher in high-grade (III and IV) glioma tissues than in low-grade (I and II) glioma tissues. The data showed that the expression of RSK4 was significantly correlated with WHO grade, three-year survival rate and five-year survival rate. Kaplan-Meier analyses showed that patients with high RSK4 expression had poor overall survival. In addition, multivariate Cox regression analysis showed that RSK4 might be an independent prognostic factor in glioma patients. Collectively, these results suggest that RSK4 may be a new prognostic factor in glioma patients, and RSK4 is expected to be a potential biomarker and a potential target for glioma therapy.

TRAF4 knockdown triggers synergistic lethality with simultaneous PARP1 inhibition in endometrial cancer

Endometrial cancer (EC) is one of the most common cancers among females worldwide. Advanced stage patients of EC have poor prognosis. Inevitable side effects and treatment tolerance of chemotherapy for EC remain to be addressed. Our results in this study showed that EC cells with higher tumor necrosis factor receptor-associated factor 4 (TRAF4) expression have lower sensitivity to poly ADP-ribose polymerase 1 (PARP1) inhibitors. Upon TRAF4 knockdown, the colony numbers of EC cells were markedly down-regulated, and the markers of DNA double-strand breakage were significantly up-regulated after the treatment of olaparib, a PARP1 inhibitor. TRAF4 knockdown reduced the phosphorylation of protein kinase B (Akt), promoted DNA double-strand breakage, and decreased levels of DNA repair related proteins, including phosphorylated-DNA-dependent protein kinase (p-DNA-PK) and RAD51 recombinase (RAD51). In addition, TRAF4's effect on the sensitivity of EC cells to olaparib was further found to be mainly mediated by Akt phosphorylation. Moreover, in vivo results showed that TRAF4 knockdown enhanced the sensitivity of EC to PARP1 inhibitors using a mouse xenograft model. Collectively, our data suggest that combined application of TRAF4 knockdown and PARP1 inhibition can be used as a promising strategy for synthetic lethality in EC treatment.

Ectopic Expression of miR-532-3p Suppresses Bone Metastasis of Prostate Cancer Cells via Inactivating NF-κB Signaling

miR-532-3p is a widely documented microRNA (miRNA) involved in multifaceted processes of cancer tumorigenesis and metastasis. However, the clinical significance and biological functions of miR-532-3p in bone metastasis of prostate cancer (PCa) remain largely unknown. Herein, we report that miR-532-3p was downregulated in PCa tissues with bone metastasis, and downexpression of miR-532-3p was significantly associated with Gleason grade and serum prostate-specific antigen (PSA) levels and predicted poor bone metastasis-free survival in PCa patients. Upregulating miR-532-3p inhibited invasion and migration abilities of PCa cells in vitro, while silencing miR-532-3p yielded an opposite effect on invasion and migration abilities of PCa cells. Importantly, upregulating miR-532-3p repressed bone metastasis of PCa cells in vivo. Our results further demonstrated that overexpression of miR-532-3p inhibited activation of nuclear facto κB (NF-κB) signaling via simultaneously targeting tumor necrosis factor receptor-associated factor 1 (TRAF1), TRAF2, and TRAF4, which further promoted invasion, migration, and bone metastasis of PCa cells. Therefore, our findings reveal a novel mechanism contributing to the sustained activity of NF-κB signaling underlying the bone metastasis of PCa.

YY1-induced lncRNA ZFPM2-AS1 facilitates cell proliferation and invasion in small cell lung cancer via upregulating of TRAF4

Background

Newly identified lncRNA zinc finger protein, FOG family member 2 antisense RNA 1 (ZFPM2-AS1) is identified as an oncogenic gene. However, the role of ZFPM2-AS1 in small cell lung cancer (SCLC) is poorly comprehended.

Methods

The expression of genes in SCLC tissues and cells was measured by qRT-PCR. Colony formation, EdU, CCK-8, transwell and wound healing as well as in vivo assays revealed the function of ZFPM2-AS1 in SCLC. ChIP, luciferase reporter, RIP and RNA pull down assays demonstrated the binding relation among genes.

Results

ZFPM2-AS1 was significantly upregulated in SCLC tissues and cells. ZFPM2-AS1 deficiency attenuated SCLC cell proliferation, invasion and migration. In addition, ZFPM2-AS1 was transcriptionally activated by Yin Yang 1 (YY1) factor. Further, miR-3612 was confirmed as downstream miRNA of ZFPM2-AS1. Moreover, TNF receptor associated factor 4 (TRAF4) was the target gene of miR-3612 in SCLC. ZFPM2-AS1, miR-3612 and TRAF4 jointly constituted a competing endogenous RNA (ceRNA) network in SCLC. Finally, TRAF4 could countervail ZFPM2-AS1 downregulation-mediated function on SCLC cell proliferation and invasion in vitro and tumor growth in vivo.

Conclusion

Our study elucidated the oncogenic effect of ZFPM2-AS1 in SCLC progression, indicating it may be a therapeutic target for SCLC.

Celecoxib Inhibits Hepatocellular Carcinoma Cell Growth and Migration by Targeting PNO1

Background

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

Material/Methods

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

Results

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

Conclusions

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

Long non‑coding RNA DLEU1 promotes cell proliferation of glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most common malignant tumor with high morbidity and mortality. This study investigated the role of long non‑coding RNAs (lncRNAs) in glioblastomagenesis progression. Using the GSE2223 and GSE59612 datasets, and RNA sequencing data of GBM from The Cancer Genome Atlas, differentially expressed (DE) genes including DE messenger RNAs (DEmRNAs) and DElncRNAs between GBM and normal controls were identified. Based on the competing endogenous RNA hypothesis, DElncRNA‑micro RNA (miRNA)‑DEmRNA interactions were obtained by target gene prediction. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes pathway analysis of DEmRNAs in the DElncRNA‑miRNA‑DEmRNA network was performed. Expression and function analyses of DElncRNAs were performed by reverse transcription‑polymerase chain reaction (RT‑PCR) and an established viability assay, respectively. In total, 712 DE genes were identified. Significant upregulation of lncRNA deleted in lymphocytic leukemia 1 (DLEU1) was revealed in GBM and a number of other types of cancer. DLEU1 interacted with 315 miRNAs and 105 DEmRNAs. The DEmRNAs were mainly enriched in tumorigenesis‑associated GO terms (angiogenesis, positive regulation of cell proliferation, positive regulation of fibroblast apoptotic processes and regulation of neutrophil migration) and pathways (Hippo signaling pathway, cancer pathways, and Wnt signaling pathway). Correlation analysis revealed that mRNA TNF receptor associated factor 4 (TRAF4) was associated with DLEU1 expression. RT‑PCR demonstrated that the expression levels of DLEU1 and TRAF4 were increased in GBM tissues. Small interfering RNA demonstrated that silencing DLEU1 downregulated TRAF4. The viability of GBM cells was significantly decreased following RNA interference with DLEU1 and TRAF4 production. The results demonstrate that DLEU1 and TRAF4 is highly expressed in GBM tissues and promotes proliferation of GBM cells. It may act as a competing endogenous RNA and influence tumorigenesis of GBM.

Triptolide Suppresses Growth of Breast Cancer by Targeting HMGB1 in Vitro and in Vivo

Triptolide has been indicated potent anti-cancer effect involving multiple molecular targets and signaling pathways. High-mobility group box 1 (HMGB1) is a highly conserved DNA-binding protein taking part in breast cancer development. The therapeutic effect of triptolide on HMGB1 has not been reported. Thus, our study aims to clarify the role of HMGB1 in triptolide-induced anti-growth effect on breast cancer in vitro and in vivo. We demonstrated that triptolide significantly suppressed growth of breast cancer cells by inhibition of cell viability, clonogenic ability. Further studies evidenced that triptolide treatment not only inhibited HMGB1 mRNA expression, but also decreased supernatant level of HMGB1 in vitro. In line with these observations, exogenous recombinant HMGB1 (rHMGB1) promoted cell proliferation of breast cancer, and triptolide reversed the rHMGB1-promoted proliferative effect. As well, triptolide enhanced the anti-proliferative activity of ethyl pyruvate (EP) (HMGB1 inhibitor). Furthermore, downstream correlation factors (Toll-like receptor 4 (TLR4) and phosphorylated-nuclear factor-kappaB (NF-κB) p65) of HMGB1 were significantly decreased in vitro after triptolide treatment. Consistantly, we confirmed that tumor growth was significantly inhibited after triptolide treatment in vivo. Meanwhile, immunohistochemical analyses showed that triptolide treatment significantly decreased the level of cytoplasmic HMGB1 and TLR4 expression, whereas the expression of NF-κB p65 was relatively higher in cytoplasm, and conversely lower in nucleus as compared to the control group. Collectively, these results demonstrate that triptolide suppresses the growth of breast cancer cells via reduction of HMGB1 expression in vitro and in vivo, which may provide new insights into the treament of breast cancer.

LncRNA MAFG-AS1 facilitates the migration and invasion of NSCLC cell via sponging miR-339-5p from MMP15

Non-small-cell carcinoma (NSCLC) is the most common cancer along with high mortality rate worldwide. In the present study, our data showed that lncRNA MAF BZIP Transcription Factor G Antisense RNA 1 (MAFG-AS1) was over-expressed in NSCLC tissues and cell lines. Overexpression of MAFG-AS1 promoted the migration, invasion and enhanced epithelial-mesenchymal transition (EMT) of NSCLC cell. In addition, miR-339-5p was predicted to be a target of MAFG-AS1 and the level of miR-339-5p was down-regulated in NSCLC. Over-expression of MAFG-AS1 significantly decreased the level of miR-339-5p in NSCLC cell. Moreover, the matrix metalloproteinase 15 (MMP15) was identified to be a target of miR-339-5p. The level of MMP15 was negatively regulated by miR-339-5p whereas positively controlled by MAFG-AS1. In addition, up-regulation of miR-339-5p neutralized the promoting impact of MAFG-AS1 on the migration, invasion and EMT of NSCLC cell. Finally, the xenograft model suggested that MAFG-AS1 promoted the metastasis of NSCLC cell in vivo. Altogether, we proved that MAFG-AS1-miR-339-5p-MMP15 axis might be a promising therapeutic target for the treatment of patients with NSCLC.

Genetic Alterations of TRAF Proteins in Human Cancers

The tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of cytoplasmic adaptor proteins regulate the signal transduction pathways of a variety of receptors, including the TNF-R superfamily, Toll-like receptors (TLRs), NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), and cytokine receptors. TRAF-dependent signaling pathways participate in a diverse array of important cellular processes, including the survival, proliferation, differentiation, and activation of different cell types. Many of these TRAF-dependent signaling pathways have been implicated in cancer pathogenesis. Here we analyze the current evidence of genetic alterations of TRAF molecules available from The Cancer Genome Atlas (TCGA) and the Catalog of Somatic Mutations in Cancer (COSMIC) as well as the published literature, including copy number variations and mutation landscape of TRAFs in various human cancers. Such analyses reveal that both gain- and loss-of-function genetic alterations of different TRAF proteins are commonly present in a number of human cancers. These include pancreatic cancer, meningioma, breast cancer, prostate cancer, lung cancer, liver cancer, head and neck cancer, stomach cancer, colon cancer, bladder cancer, uterine cancer, melanoma, sarcoma, and B cell malignancies, among others. Furthermore, we summarize the key in vivo and in vitro evidence that demonstrates the causal roles of genetic alterations of TRAF proteins in tumorigenesis within different cell types and organs. Taken together, the information presented in this review provides a rationale for the development of therapeutic strategies to manipulate TRAF proteins or TRAF-dependent signaling pathways in different human cancers by precision medicine.

Genetic Alterations of TRAF Proteins in Human Cancers

The tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of cytoplasmic adaptor proteins regulate the signal transduction pathways of a variety of receptors, including the TNF-R superfamily, Toll-like receptors (TLRs), NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), and cytokine receptors. TRAF-dependent signaling pathways participate in a diverse array of important cellular processes, including the survival, proliferation, differentiation, and activation of different cell types. Many of these TRAF-dependent signaling pathways have been implicated in cancer pathogenesis. Here we analyze the current evidence of genetic alterations of TRAF molecules available from The Cancer Genome Atlas (TCGA) and the Catalog of Somatic Mutations in Cancer (COSMIC) as well as the published literature, including copy number variations and mutation landscape of TRAFs in various human cancers. Such analyses reveal that both gain- and loss-of-function genetic alterations of different TRAF proteins are commonly present in a number of human cancers. These include pancreatic cancer, meningioma, breast cancer, prostate cancer, lung cancer, liver cancer, head and neck cancer, stomach cancer, colon cancer, bladder cancer, uterine cancer, melanoma, sarcoma, and B cell malignancies, among others. Furthermore, we summarize the key in vivo and in vitro evidence that demonstrates the causal roles of genetic alterations of TRAF proteins in tumorigenesis within different cell types and organs. Taken together, the information presented in this review provides a rationale for the development of therapeutic strategies to manipulate TRAF proteins or TRAF-dependent signaling pathways in different human cancers by precision medicine.