FOXP4-mediated induction of PTK7 activates the Wnt/ß-catenin pathway and promotes ovarian cancer development.

Ovarian cancer (OV) poses a significant challenge in clinical settings due to its difficulty in early diagnosis and treatment resistance. FOXP4, belonging to the FOXP subfamily, plays a pivotal role in various biological processes including cancer, cell cycle regulation, and embryonic development. However, the specific role and importance of FOXP4 in OV have remained unclear. Our research showed that FOXP4 is highly expressed in OV tissues, with its elevated levels correlating with poor prognosis. We further explored FOXP4's function through RNA sequencing and functional analysis in FOXP4-deficient cells, revealing its critical role in activating the Wnt signaling pathway. This activation exacerbates the malignant phenotype in OV. Mechanistically, FOXP4 directly induces the expression of protein tyrosine kinase 7 (PTK7), a Wnt-binding receptor tyrosine pseudokinase, which causes abnormal activation of the Wnt signaling pathway. Disrupting the FOXP4-Wnt feedback loop by inactivating the Wnt signaling pathway or reducing FOXP4 expression resulted in the reduction of the malignant phenotype of OV cells, while restoring PTK7 expression reversed this effect. In conclusion, our findings underscore the significance of the FOXP4-induced Wnt pathway activation in OV, suggesting the therapeutic potential of targeting this pathway in OV treatment.

HIF1A-dependent overexpression of MTFP1 promotes lung squamous cell carcinoma development by activating the glycolysis pathway.

Introduction: Mitochondrial fission process 1 (MTFP1) is an inner mitochondrial membrane (IMM) protein implicated in the development and progression of various tumors, particularly lung squamous cell carcinoma (LUSC). This study aims to provide a more theoretical basis for the treatment of LUSC. Methods: Through bioinformatics analysis, MTFP1 was identified as a novel target gene of HIF1A. MTFP1 expression in LUSC was examined using The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Proteomics Data Commons (PDC) databases. The Kaplan-Meier plotter (KM plotter) database was utilized to evaluate its correlation with patient survival. Western blot and chromatin immunoprecipitation (ChIP) assays were employed to confirm the regulatory relationship between MTFP1 and HIF1A. Additionally, cell proliferation, colony formation, and migration assays were conducted to investigate the mechanism by which MTFP1 enhances LUSC cell proliferation and metastasis. Results: Our findings revealed that MTFP1 overexpression correlated with poor prognosis in LUSC patients(P < 0.05). Moreover, MTFP1 was closely associated with hypoxia and glycolysis in LUSC (R = 0.203; P < 0.001, R = 0.391; P < 0.001). HIF1A was identified as a positive regulator of MTFP1. Functional enrichment analysis demonstrated that MTFP1 played a role in controlling LUSC cell proliferation. Cell proliferation, colony formation, and migration assays indicated that MTFP1 promoted LUSC cell proliferation and metastasis by activating the glycolytic pathway (P < 0.05). Conclusions: This study establishes MTFP1 as a novel HIF1A target gene that promotes LUSC growth by activating the glycolytic pathway. Investigating MTFP1 may contribute to the development of effective therapies for LUSC patients, particularly those lacking targeted oncogene therapies.

CENPK orchestrates ovarian cancer progression via GOLPH3-Mediated activation of mTOR signaling.

Ovarian cancer stands as a formidable clinical challenge, with limited therapeutic options. This investigation delves into the intricate molecular mechanisms governing ovarian cancer progression and uncovers Centromere Protein K (CENPK) as a central figure in disease pathogenesis. Elevated CENPK levels within ovarian cancer tissues conspicuously align with adverse clinical outcomes, positioning CENPK as a promising prognostic biomarker. Deeper exploration reveals a direct transcriptional connection between CENPK and the E2F1 transcription factor and clearly establishes E2F1's role as the master regulator of CENPK expression in ovarian cancer. Our inquiry revealing a suppression of tumor-promoting signaling pathways, most notably the mTOR pathway, upon CENPK silencing. Intriguingly, CENPK renders ovarian cancer cells more responsive to the mTOR inhibitor rapamycin, introducing a promising avenue for therapeutic intervention. In summation, our study unravels the multifaceted role of CENPK in ovarian cancer progression. It emerges as a prognostic indicator, a pivotal mediator of cell proliferation and tumorigenicity, and a regulator of the mTOR pathway, shedding light on potential therapeutic avenues for this formidable disease.

JHD205, A Novel Abemaciclib Derivative, Exerts Antitumor Effects on Breast Cancer by CDK4/6.

BACKGROUND: Efficient targeted molecular therapeutics are needed for the treatment of triple-negative breast cancer (TNBC), a highly invasive and difficult-to-treat form of breast cancer associated with a poor prognosis. OBJECTIVES: This study aims to evaluate the potential of selective CDK4/6 inhibitors as a therapeutic option for TNBC by impairing the cell cycle G1 phase through the inhibition of retinoblastoma protein (Rb) phosphorylation. METHODS: In this study, we synthesized a compound called JHD205, derived from the chemical structure of Abemaciclib, and examined its inhibitory effects on the malignant characteristics of TNBC cells. RESULTS: Our results demonstrated that JHD205 exhibited superior tumor growth inhibition compared to Abemaciclib in breast cancer xenograft chicken embryo models. Western blot analysis revealed that JHD205 could dosedependently degrade CDK4 and CDK6 while also causing abnormal changes in other proteins associated with CDK4/6, such as p-Rb, Rb, and E2F1. Moreover, JHD205 induced apoptosis and DNA damage and inhibited DNA repair by upregulating Caspase3 and p-H2AX protein levels. CONCLUSION: Collectively, our findings suggest that JHD205 holds promise as a potential treatment for breast carcinoma.

FBXO5-mediated RNF183 degradation prevents endoplasmic reticulum stress-induced apoptosis and promotes colon cancer progression.

Endoplasmic reticulum (ER) stress induces the unfolded protein response (UPR), and prolonged ER stress leads to cell apoptosis. Despite increasing research in this area, the underlying molecular mechanisms remain unclear. Here, we discover that ER stress upregulates the UPR signaling pathway while downregulating E2F target gene expression and inhibiting the G2/M phase transition. Prolonged ER stress decreases the mRNA levels of E2F2, which specifically regulates the expression of F-Box Protein 5(FBXO5), an F-box protein that functions as an inhibitor of the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase complex. Depletion of FBXO5 results in increased ER stress-induced apoptosis and decreased expression of proteins related to PERK/IRE1α/ATF6 signaling. Overexpression of FBXO5 wild-type (not its ΔF-box mutant) alleviates apoptosis and the expression of the C/EBP Homologous Protein (CHOP)/ATF. Mechanistically, we find that FBXO5 directly binds to and promotes the ubiquitin-dependent degradation of RNF183, which acts as a ubiquitin E3 ligase in regulating ER stress-induced apoptosis. Reversal of the apoptosis defects caused by FBXO5 deficiency in colorectal cancer cells can be achieved by knocking down RNF183 in FBXO5-deficient cells. Functionally, we observed significant upregulation of FBXO5 in colon cancer tissues, and its silencing suppresses tumor occurrence in vivo. Therefore, our study highlights the critical role of the FBXO5/RNF183 axis in ER stress regulation and identifies a potential therapeutic target for colon cancer treatment.

ß-catenin/TCF4-induced SCUBE3 upregulation promotes ovarian cancer development via HIF-1 signaling pathway.

The precise involvement and mechanistic role of the signal peptide-CUB-EGF-like domain-containing protein 3 (SCUBE3) in ovarian cancer (OV) remain poorly understood. Here, leveraging comprehensive data from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, we unveil the selective overexpression of SCUBE3 in ovarian cancer tissues and cells. Intriguingly, elevated SCUBE3 expression levels correlate with an unfavorable prognosis in patients. Through meticulous manipulation of SCUBE3 expression, we elucidate its consequential impact on in vitro proliferation and invasion of ovarian cancer cells, as well as in vivo tumor growth in mice. Our multifaceted investigations, encompassing luciferase reporter assays, chromatin immunoprecipitation (ChIP) experiments, and mining of public databases, successfully identify SCUBE3 as a direct downstream target gene of TCF4-a pivotal positive regulator within the ß-catenin/TCF4 complex. Furthermore, utilizing a recessive mutant mouse line (kta41) harboring a functionally impaired point mutation at position 882 in the SCUBE3 gene, we uncover SCUBE3's involvement in the intricate regulation of angiogenesis and epithelial-mesenchymal transition (EMT). Strikingly, Spearman correlation coefficient analysis unveils a close association between SCUBE3 and HIF1A in OV, with SCUBE3 exerting tight control over HIF1A mRNA expression. Moreover, functional inhibition of HIF1A significantly impedes the pro-proliferative and invasive capabilities of SCUBE3-overexpressing ovarian cancer cells. Collectively, our findings underscore the pivotal role of SCUBE3 in driving ovarian cancer progression, shedding light on its intricate molecular mechanisms and establishing it as a potential therapeutic target for this devastating disease.

USP14 regulates heme metabolism and ovarian cancer invasion through BACH1 deubiquitination and stabilization.

The deubiquitinating enzyme USP14 has been established as a crucial regulator in various diseases, including tumors, neurodegenerative diseases, and metabolic diseases, through its ability to stabilize its substrate proteins. Our group has utilized proteomic techniques to identify new potential substrate proteins for USP14, however, the underlying signaling pathways regulated by USP14 remain largely unknown. Here, we demonstrate the key role of USP14 in both heme metabolism and tumor invasion by stabilizing the protein BACH1. The cellular oxidative stress response factor NRF2 regulates antioxidant protein expression through binding to the antioxidant response element (ARE). BACH1 can compete with NRF2 for ARE binding, leading to the inhibition of the expression of antioxidant genes, including HMOX-1. Activated NRF2 also inhibits the degradation of BACH1, promoting cancer cell invasion and metastasis. Our findings showed a positive correlation between USP14 expression and NRF2 expression in various cancer tissues from the TCGA database and normal tissues from the GTEx database. Furthermore, activated NRF2 was found to increase USP14 expression in ovarian cancer (OV) cells. The overexpression of USP14 was observed to inhibit HMOX1 expression, while USP14 knockdown had the opposite effect, suggesting a role for USP14 in regulating heme metabolism. The depletion of BACH1 or inhibition of heme oxygenase 1 (coded by HMOX-1) was also found to significantly impair USP14-dependent OV cell invasion. In conclusion, our results highlight the importance of the NRF2-USP14-BACH1 axis in regulating OV cell invasion and heme metabolism, providing evidence for its potential as a therapeutic target in related diseases.

The atypical ubiquitin ligase RNF31 stabilizes c-Myc via epigenetic inactivation of FBXO32 and promotes cancer development.

RNF31, an atypical E3 ubiquitin ligase of the RING-between-RING protein family, is one of the important components of the linear ubiquitin chain complex LUBAC. It plays a carcinogenic role in a variety of cancers by promoting cell proliferation, invasion and inhibiting apoptosis. However, the specific molecular mechanism by which RNF31 exerts its cancer-promoting effects is still unclear. By analyzing the expression profile of RNF31-depleted cancer cells, we found that loss of RNF31 significantly resulted in the inactivation of the c-Myc pathway. We further showed that RNF31 played an important role in the maintenance of c-Myc protein levels in cancer cells by extending the half-life of c-Myc protein and reducing its ubiquitination. c-Myc protein levels are tightly regulated by the ubiquitin proteasome, in which the E3 ligase FBXO32 is required to mediate its ubiquitin-dependent degradation. We found that RNF31 inhibited the transcription of FBXO32 through EZH2-mediated trimethylation of histone H3K27 in the FBXO32 promoter region, leading to the stabilization and activation of c-Myc protein. Under this circumstance, the expression of FBXO32 was significantly increased in RNF31-deficient cells, promoting the degradation of c-Myc protein, inhibiting cell proliferation and invasion, increasing cell apoptosis, and ultimately blocking the progression of tumors. Consistent with these results, the reduced malignancy phenotype caused by RNF31 deficiency could be partially reversed by overexpression of c-Myc or further knockdown of FBXO32. Together, our results reveal a key association between RNF31 and epigenetic inactivation of FBXO32 in cancer cells, and suggest that RNF31 may be a promising target for cancer therapy.

Epigenetic reactivation of PEG3 by EZH2 inhibitors suppresses renal clear cell carcinoma progress.

PEG3 is a paternally imprinted gene located on chromosome 19q13.4 and one of the most common low-expression genes in human ovarian cancer. PEG3 plays an important role in p53-related cell death. However, whether PEG3 plays a role in renal clear cell carcinoma (ccRCC) remains unclear. Here, we found that PEG3 was epigenetic inactivated and played a tumor suppressor role in ccRCC. Overexpression of PEG3 inhibited ccRCC cell proliferation and colony formation, while removal of PEG3 significantly promoted cell proliferation in vitro and tumor formation in nude mice in vivo. EZH2-mediated H3K27me3 at the PEG3 promoter suppressed PEG3 expression. EZH2 specific inhibitors promote PEG3 transcriptional expression through the transition from H3K27me3 to H3K27ac at the PEG3 promoter region. Depletion of PEG3 inhibited the activation of the p53 signaling pathway, resulting in the resistance of ccRCC to EZH2 inhibitors treatment. Thus, our data show that EZH2-mediated epigenetic inactivation of PEG3 promotes the progress of ccRCC, and reactivation of PEG3 may be a promising strategy for ccRCC.

VHL-HIF-2α axis-induced SEMA6A upregulation stabilized ß-catenin to drive clear cell renal cell carcinoma progression.

SEMA6A is a multifunctional transmembrane semaphorin protein that participates in various cellular processes, including axon guidance, cell migration, and cancer progression. However, the role of SEMA6A in clear cell renal cell carcinoma (ccRCC) is unclear. Based on high-throughput sequencing data, here we report that SEMA6A is a novel target gene of the VHL-HIF-2α axis and overexpressed in ccRCC. Chromatin immunoprecipitation and reporter assays revealed that HIF-2α directly activated SEMA6A transcription in hypoxic ccRCC cells. Wnt/ß-catenin pathway activation is correlated with the expression of SEMA6A in ccRCC; the latter physically interacted with SEC62 and promoted ccRCC progression through SEC62-dependent ß-catenin stabilization and activation. Depletion of SEMA6A impaired HIF-2α-induced Wnt/ß-catenin pathway activation and led to defective ccRCC cell proliferation both in vitro and in vivo. SEMA6A overexpression promoted the malignant phenotypes of ccRCC, which was reversed by SEC62 depletion. Collectively, this study revealed a potential role for VHL-HIF-2α-SEMA6A-SEC62 axis in the activation of Wnt/ß-catenin pathway. Thus, SEMA6A may act as a potential therapeutic target, especially in VHL-deficient ccRCC.

Identification of the deubiquitinase USP28 as a novel molecular therapeutic target of ovarian cancer.

Ubiquitin specific proteinase 28 (USP28) is a member of the deubiquitylating enzymes, which are mainly involved in cell cycle, apoptosis and DNA damage repair. Although USP28 has been found to be upregulated in some tumors, its role in ovarian cancer (OV) remains unclear. Here we show that USP28 was highly expressed in OV samples compared with normal ovarian tissue, and OV patients with higher USP28 levels had a worse prognosis. We found that the abnormal expression of USP28 mRNA in OV was related to the activation of ß-catenin signaling pathway, and USP28 was a transcriptional target gene of the ß-catenin/YAP1/TBX5 complex. In addition, genetic ablation or pharmacological inhibition of USP28 impaired the proliferation ability of OV cells in vitro and in vivo. In conclusion, our findings show that ß-catenin/YAP1/TBX5-mediated aberrant expression of USP28 promotes the malignant phenotype of OV, suggesting that USP28 may be a therapeutic target for OV.

FBXO2 targets glycosylated SUN2 for ubiquitination and degradation to promote ovarian cancer development.

SAD1/UNC84 domain protein-2 (SUN2) plays a tumor suppressor role in various types of cancer by inhibiting cancer cell proliferation, migration and promoting apoptosis. However, the post-translational regulation of SUN2 and the cellular mechanism responsible for its proteasomal degradation remains largely unknown. Here, we show that FBXO2, an E3 ubiquitin ligase of the F-box proteins (FBPs) family targets glycosylated SUN2 for ubiquitination and degradation via the ubiquitin-proteasome system (UPS). By integrating the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and the Encyclopedia of Cancer Cell Lines (CCLE) databases, we revealed that FBXO2 was selectively highly expressed in ovarian cancer (OV) tissues and cells. Patients with relatively high FBXO2 expression levels were associated with worse prognosis. Manipulation of the expression of FBXO2 affecting ovarian cancer cell proliferation, migration/invasion in vitro, and tumor growth in mice in vivo. The transcription factor SOX6 promoted FBXO2 expression by recognizing a putative response element localized on the promoter region of FBXO2. Abnormally highly expressed FBXO2 recognized and targeted glycosylated SUN2 protein for ubiquitination-depended degradation to prevent cell apoptosis, promote cell proliferation, and ultimately promote the progression of OV. Thus, we revealed a new SOX6-FBXO2-SUN2 axis that contributed to the development of OV, and targeting this axis may represent an effective OV treatment strategy.

The USP18-FBXO6 axis maintains the malignancy of ovarian cancer.

Ubiquitin-specific protease 18 (USP18) is a deubiquitinating enzyme that reverses the post-translational modification of target proteins by ISG15 or ubiquitin, and is involved in a variety of cellular processes, including signal transduction, viral infection, and cancer development. Although high levels of USP18 mRNA have been observed in several types of cancer, its pathological significance in ovarian cancer (OV) is still elusive. Here, by integrating the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Genotypic Tissue Expression (GTEx) databases, we found that USP18 was abnormally up-regulated in OV tissues, and the increased expression of USP18 was associated with poor prognosis. We further showed that activated Jak-STAT3 signaling induced the expression of USP18, which in turn feedback maintained the activity of Jak-STAT3 signaling in OV. In addition, we found that USP18 played a cancer-promoting role in OV mainly through the transcriptional regulation of FBXO6. Silencing USP18 reduced the malignancy of OV, which can be largely reversed by overexpression of FBXO6. On the contrary, silencing FBXO6 significantly weaken the pro-proliferation function of USP18 in OV cells. In summary, our results indicate that USP18 is a downstream target gene of STAT3, and the USP18-FBXO6 axis might be a promising therapeutic target for OV.

ATAD2 drives colorectal cancer progression by regulating TRIM25 expression via a positive feedback loop with E2F transcriptional factors.

ATPase family AAA domain-containing protein 2 (ATAD2) is highly expressed in a variety of cancer types, and acts as a co-activator of androgen and estrogen receptors, as well as MYC and E2F transcription factors, to promote tumor cell proliferation. However, the regulation of ATAD2 and its related mechanisms are still elusive. Here, we show that ATAD2 protein was stabilized during DNA damage response in colorectal cancer (CRC) cells. TRIM25, an oncogenic ubiquitin E3 ligase, can interact with ATAD2 and stabilize ATAD2 upon genotoxic insult. We further demonstrated that ATAD2 played a tumor promoting role in CRC and acted as a transcriptional co-activator of E2Fs to promote the expression of TRIM25. Thus, our results revealed an unknown ATAD2-E2Fs-TRIM25 positive feedback loop that drove CRC progression.

SOX9-mediated UGT8 expression promotes glycolysis and maintains the malignancy of non-small cell lung cancer.

UDP-glycosyltransferases (UGTs) catalyze the covalent addition of sugars to small lipophilic chemicals and are associated with a wide range of diseases including cancer. The human genome contains 22 UGT genes which could be classified into four families: UGT1, UGT2, UGT3, and UGT8. The UGT8 family contains only one member which utilizes UDP galactose to galactosidate ceramide. Although higher UGT8 mRNA was observed in some types of cancer, its pathological significances remain elusive. Here, by integrating the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and the Genotype-Tissue Expression (GTEx) databases, we showed that UGT8 was selectively highly expressed in non-small cell lung cancer (NSCLC) and associated with worse prognosis. The transcription factor SOX9 promoted UGT8 expression in NSCLC by recognizing two putative response elements localized on the promoter region of UGT8. Silencing UGT8 impaired glycolysis and reduced the malignancy of NSCLC cells both in vitro and in vivo. On the contrary, inhibition of glycolysis by 2-deoxy-d-glucose (2-DG) significantly impaired the pro-proliferation function of UGT8 in NSCLC cells. In conclusion, our results suggest that UGT8 maintains the malignancy of NSCLC mainly via enhanced glycolysis and provides a promising therapeutic target for NSCLC.

Sustained ER stress promotes hyperglycemia by increasing glucagon action through the deubiquitinating enzyme USP14.

Endoplasmic reticulum (ER) stress plays an important role in metabolic diseases like obesity and type 2 diabetes mellitus (T2DM), although the underlying mechanisms and regulatory pathways remain to be elucidated. Here, we induced chronic low-grade ER stress in lean mice to levels similar to those in high-fat diet (HFD)-fed obese mice and found that it promoted hyperglycemia due to enhanced hepatic gluconeogenesis. Mechanistically, sustained ER stress up-regulated the deubiquitinating enzyme ubiquitin-specific peptidase 14 (USP14), which increased the stability and levels of 3',5'-cyclic monophosphate-responsive element binding (CREB) protein (CBP) to enhance glucagon action and hepatic gluconeogenesis. Exogenous overexpression of USP14 in the liver significantly increased hepatic glucose output. Consistent with this, liver-specific knockdown of USP14 abrogated the effects of ER stress on glucose metabolism, and also improved hyperglycemia and glucose intolerance in obese mice. In conclusion, our findings show a mechanism underlying ER stress-induced disruption of glucose homeostasis, and present USP14 as a potential therapeutic target against T2DM.