Histone demethylase KDM7A is required for stem cell maintenance and apoptosis inhibition in breast cancer

Competing endogenous RNAs regulatory crosstalk networks: The messages from the RNA world to signaling pathways directing cancer stem cell development

Cancer stem cells (CSCs) are one of the cell types that account for cancer heterogeneity. The cancer cells arrest in G0 and generate non-CSC progeny through self-renewal and pluripotency, resulting in tumor recurrence, metastasis, and resistance to chemotherapy. They can stimulate tumor relapse and re-grow a metastatic tumor. So, CSCs is a promising target for eradicating tumors, and developing an anti-CSCs therapy has been considered. In recent years competing endogenous RNA (ceRNA) has emerged as a significant class of post-transcriptional regulators that affect gene expression via competition for microRNA (miRNA) binding. Furthermore, aberrant ceRNA expression is associated with tumor progression. Recent findings show that ceRNA network can cause tumor progression through the effect on CSCs. To overcome therapeutic resistance due to CSCs, we need to improve our current understanding of the mechanisms by which ceRNAs are implicated in CSC-related relapse. Thus, this review was designed to discuss the role of ceRNAs in CSCs' function. Targeting ceRNAs may open the path for new cancer therapeutic targets and can be used in clinical research.

Combined expression of JHDM1D/KDM7A gene and long non-coding RNA RP11-363E7.4 as a biomarker for urothelial cancer prognosis

Bladder cancer is the tenth most frequently diagnosed cancer globally. Classification of high- or low-grade tumors is based on cytological differentiation and is an important prognostic factor. LncRNAs regulate gene expression and play critical roles in the occurrence and development of cancer, however, there are few reports on their diagnostic value and co-expression levels with genes, which may be useful as specific biomarkers for prognosis and therapy in bladder cancer. Thus, we performed a marker lesion study to investigate whether gene/lncRNA expression in urothelial carcinoma tissues may be useful in differentiating low-grade and high-grade tumors. RT-qPCR was used to evaluate the expression of the JHDM1D gene and the lncRNAs CTD-2132N18.2, SBF2-AS1, RP11-977B10.2, CTD-2510F5.4, and RP11-363E7.4 in 20 histologically diagnosed high-grade and 10 low-grade tumors. A protein-to-protein interaction network between genes associated with JHDM1D gene was constructed using STRING website. The results showed a moderate (positive) correlation between CTD-2510F5.4 and CTD2132N18.2. ROC curve analyses showed that combined JHDM1D and RP11-363E7.4 predicted tumor grade with an AUC of 0.826, showing excellent accuracy. In conclusion, the results indicated that the combined expression of JHDM1D and RP11-363E7.4 may be a prognostic biomarker and a promising target for urothelial tumor therapy.

A Genome-Wide Association Study of Endoxifen Serum Concentrations and Adjuvant Tamoxifen Efficacy in Early-Stage Breast Cancer Patients

Tamoxifen is part of the standard of care of endocrine therapy for adjuvant treatment of breast cancer. However, survival outcomes with tamoxifen are highly variable. The concentration of endoxifen, the 30-100 times more potent metabolite of tamoxifen and bioactivated by the CYP2D6 enzyme, has been described as the most relevant metabolite of tamoxifen metabolism. A genome-wide association study (GWAS) was performed with the objective to identify genetic polymorphisms associated with endoxifen serum concentration levels and clinical outcome in early-stage breast cancer patients receiving tamoxifen. A GWAS was conducted in 608 women of the CYPTAM study (NTR1509/PMID: 30120701). Germline DNA and clinical and survival characteristics were readily available. Genotyping was performed on Infinium Global Screening Array (686,082 markers) and single nucleotide polymorphism (SNP) imputation by using 1000 Genomes. Relapse-free survival during tamoxifen (RFSt) was defined the primary clinical outcome. Endoxifen serum concentration was analyzed as a continuous variable. Several genetic variants reached genome-wide significance (P value: ≤5 × 10-8). Endoxifen concentrations analysis identified 430 variants, located in TCF20 and WBP2NL genes (chromosome 22), which are in strong linkage disequilibrium with CYP2D6 variants. In the RFSt analysis, several SNP were identified (LPP gene: rs77693286, HR 18.3, 95% CI: 15.2-21.1; rs6790761, OR 18.2, 95% CI: 15.5-21.1). Endoxifen concentrations have a strong association with the chromosome 22, which contains the CYP2D6 gene.

Nuclear miR-451a activates KDM7A and leads to cetuximab resistance in head and neck squamous cell carcinoma

Cetuximab resistance has been a major challenge for head and neck squamous cell carcinoma (HNSCC) patients receiving targeted therapy. However, the mechanism that causes cetuximab resistance, especially microRNA (miRNA) regulation, remains unclear. Growing evidence suggests that miRNAs may act as "nuclear activating miRNAs" for targeting promoter regions or enhancers related to target genes. This study elucidates a novel mechanism underlying cetuximab resistance in HNSCC involving the nuclear activation of KDM7A transcription via miR-451a. Herein, small RNA sequencing, quantitative real-time polymerase chain reaction (qRT‒PCR) and fluorescence in situ hybridization (FISH) results provided compelling evidence of miR-451a nuclear enrichment in response to cetuximab treatment. Chromatin isolation via RNA purification, microarray analysis, and bioinformatic analysis revealed that miR-451a interacts with an enhancer region in KDM7A, activating its expression and further facilitating cetuximab resistance. It has also been demonstrated that the activation of KDM7A by nuclear miR-451a is induced by cetuximab treatment and is AGO2 dependent. Logistic regression analyses of 87 HNSCC samples indicated the significance of miR-451a and KDM7A in the development of cetuximab resistance. These discoveries support the potential of miR-451a and KDM7A as valuable biomarkers for cetuximab resistance and emphasize the function of nuclear-activating miRNAs.

The emerging roles of histone demethylases in cancers

Modulation of histone methylation status is regarded as an important mechanism of epigenetic regulation and has substantial clinical potential for the therapy of diseases, including cancer and other disorders. The present study aimed to provide a comprehensive introduction to the enzymology of histone demethylases, as well as their cancerous roles, molecular mechanisms, therapeutic possibilities, and challenges for targeting them, in order to advance drug design for clinical therapy and highlight new insight into the mechanisms of these enzymes in cancer. A series of clinical trials have been performed to explore potential roles of histone demethylases in several cancer types. Numerous targeted inhibitors associated with immunotherapy, chemotherapy, radiotherapy, and targeted therapy have been used to exert anticancer functions. Future studies should evaluate the dynamic transformation of histone demethylases leading to carcinogenesis and explore individual therapy.

KDM7A-DT induces genotoxic stress, tumorigenesis, and progression of p53 missense mutation-associated invasive breast cancer

Stress-induced promoter-associated and antisense lncRNAs (si-paancRNAs) originate from a reservoir of oxidative stress (OS)-specific promoters via RNAPII pausing-mediated divergent antisense transcription. Several studies have shown that the KDM7A divergent transcript gene (KDM7A-DT), which encodes a si-paancRNA, is overexpressed in some cancer types. However, the mechanisms of this overexpression and its corresponding roles in oncogenesis and cancer progression are poorly understood. We found that KDM7A-DT expression is correlated with highly aggressive cancer types and specific inherently determined subtypes (such as ductal invasive breast carcinoma (BRCA) basal subtype). Its regulation is determined by missense TP53 mutations in a subtype-specific context. KDM7A-DT transcribes several intermediate-sized ncRNAs and a full-length transcript, exhibiting distinct expression and localization patterns. Overexpression of KDM7A-DT upregulates TP53 protein expression and H2AX phosphorylation in nonmalignant fibroblasts, while in semi-transformed fibroblasts, OS superinduces KDM7A-DT expression in a TP53-dependent manner. KDM7A-DT knockdown and gene expression profiling in TP53-missense mutated luminal A BRCA variant, where it is abundantly expressed, indicate its significant role in cancer pathways. Endogenous over-expression of KDM7A-DT inhibits DNA damage response/repair (DDR/R) via the TP53BP1-mediated pathway, reducing apoptosis and promoting G2/M checkpoint arrest. Higher KDM7A-DT expression in BRCA is associated with KDM7A-DT locus gain/amplification, higher histologic grade, aneuploidy, hypoxia, immune modulation scores, and activation of the c-myc pathway. Higher KDM7A-DT expression is associated with relatively poor survival outcomes in patients with luminal A or Basal subtypes. In contrast, it is associated with favorable outcomes in patients with HER2+ER- or luminal B subtypes. KDM7A-DT levels are coregulated with critical transcripts and proteins aberrantly expressed in BRCA, including those involved in DNA repair via non-homologous end joining and epithelial-to-mesenchymal transition pathway. In summary, KDM7A-DT and its si-lncRNA exhibit several intrinsic biological and clinical characteristics that suggest important roles in invasive BRCA and its subtypes. KDM7A-DT-defined mRNA and protein subnetworks offer resources for identifying clinically relevant RNA-based signatures and prospective targets for therapeutic intervention.

Kdm7a expression is spatiotemporally regulated in developing Xenopus laevis embryos, and its overexpression influences late retinal development

BACKGROUND

Post-translational histone modifications are among the most common epigenetic modifications that orchestrate gene expression, playing a pivotal role during embryonic development and in various pathological conditions. Among histone lysine demethylases, KDM7A, also known as KIAA1718 or JHDM1D, catalyzes the demethylation of H3K9me1/2 and H3K27me1/2, leading to transcriptional regulation. Previous data suggest that KDM7A plays a central role in several biological processes, including cell proliferation, commitment, differentiation, apoptosis, and maintenance. However, information on the expression pattern of KDM7A in whole organisms is limited, and its functional role is still unclear.

RESULTS

In Xenopus development, kdm7a is expressed early, undergoing spatiotemporal regulation in various organs and tissues, including the central nervous system and the eye. Focusing on retinal development, we found that kdm7a overexpression does not affect the expression of genes critically involved in early neural development and eye-field specification, whereas unbalances the distribution of neural cell subtypes in the mature retina by disfavoring the development of ganglion cells while promoting that of horizontal cells.

CONCLUSIONS

Kdm7a is dynamically expressed during embryonic development, and its overexpression influences late retinal development, suggesting a potential involvement in the molecular machinery regulating the spatiotemporally ordered generation of retinal neuronal subtypes.

Histone demethylase KDM7A regulates bone homeostasis through balancing osteoblast and osteoclast differentiation

Histone methylation plays a crucial role in various cellular processes. We previously reported the in vitro function of histone lysine demethylase 7 A (KDM7A) in osteoblast and adipocyte differentiation. The current study was undertaken to investigate the physiological role of KDM7A in bone homeostasis and elucidate the underlying mechanisms. A conditional strategy was employed to delete the Kdm7a gene specifically in osterix-expressing osteoprogenitor cells in mice. The resulting mutant mice exhibited a significant increase in cancellous bone mass, accompanied by an increase in osteoblasts and bone formation, as well as a reduction in osteoclasts, marrow adipocytes and bone resorption. The bone marrow stromal cells (BMSCs) and calvarial pre-osteoblastic cells derived from the mutant mice exhibited enhanced osteogenic differentiation and suppressed adipogenic differentiation. Additionally, osteoclastic precursor cells from the mutant mice exhibited impaired osteoclast differentiation. Co-culturing BMSCs from the mutant mice with wild-type osteoclast precursor cells resulted in the inhibition of osteoclast differentiation. Mechanistic investigation revealed that KDM7A was able to upregulate the expression of fibroblast activation protein α (FAP) and receptor activator of nuclear factor κB ligand (RANKL) in BMSCs through removing repressive di-methylation marks of H3K9 and H3K27 from Fap and Rankl promoters. Moreover, recombinant FAP attenuated the dysregulation of osteoblast and adipocyte differentiation in BMSCs from Kdm7a deficient mice. Finally, Kdm7a deficiency prevented ovariectomy-induced bone loss in mice. This study establish the role of KDM7A in bone homeostasis through its epigenetic regulation of osteoblast and osteoclast differentiation. Consequently, inhibiting KDM7A may prove beneficial in ameliorating osteoporosis. KDM7A suppresses osteoblast differentiation and bone formation through. upregulating FAP expression and inactivating canonical Wnt signaling, and conversely promotes osteoclast differentiation and bone resorption through upregulating RANKL expression. These are based on its epigenetic removal of the repressive H3K9me2 and H3K27me2 marks from Fap and Rankl promoters. As a result, the expression of KDM7A in osteoprogenitor cells tends to negatively modulate bone mass.

Lysine-specific demethylase 7A (KDM7A): A potential target for disease therapy

Histone demethylation is a kind of epigenetic modification mediated by a variety of enzymes and participates in regulating multiple physiological and pathological events. Lysine-specific demethylase 7A is a kind of α-ketoglutarate- and Fe(II)-dependent demethylase belonging to the PHF2/8 subfamily of the JmjC demethylases. KDM7A is mainly localized in the nucleus and contributes to transcriptional activation via removing mono- and di-methyl groups from the lysine residues 9 and 27 of Histone H3. Mounting studies support that KDM7A is not only necessary for normal embryonic, neural, and skeletal development, but also associated with cancer, inflammation, osteoporosis, and other diseases. Herein, the structure of KDM7A is described by comparing the similarities and differences of its amino acid sequences of KDM7A and other Histone demethylases; the functions of KDM7A in homeostasis and dyshomeostasis are summarized via documenting its content and related signaling; the currently known KDM7A-specific inhibitors and their structural relationship are listed based on their structure optimization and pharmacological activities; and the challenges and opportunities in exploring functions and developing targeted agents of KDM7A are also prospected via presenting encountered problems and potential solutions, which will provide an insight in functional exploration and drug discovery for KDM7A-related diseases.

The dual functions of KDM7A in HBV replication and immune microenvironment

KDM7A (lysine demethylase 7A, also known as JHDM1D) is a histone demethylase, it is mainly involved in the intracellular post-translational modifications process. Recently, it has been proved that the histone demethylase members can regulate the replication of hepatitis B virus (HBV) and the expression of key molecules in the Janus-activated kinase-signal transducer and activator of the transcription (JAK/STAT) signaling pathway by chromatin modifying mechanisms. In our study, we identify novel roles of KDM7A in HBV replication and immune microenvironment through two subjects: pathogen and host. On the one hand, KDM7A is highly expressed in HBV-infected cells and promotes HBV replication in vitro and in vivo. Moreover, KDM7A interacts with HBV covalently closed circular DNA and augments the activity of the HBV core promoter. On the other hand, KDM7A can remodel the immune microenvironment. It inhibits the expression of interferon-stimulated genes (ISGs) through the IFN-γ/JAK2/STAT1 signaling pathway in both hepatocytes and macrophages. Further study shows that KDM7A interacts with JAK2 and STAT1 and affects their methylation. In general, we demonstrate the dual functions of KDM7A in HBV replication and immune microenvironment, and then we propose a new therapeutic target for HBV infection and immunotherapy. IMPORTANCE Histone lysine demethylase KDM7A can interact with covalently closed circular DNA and promote the replication of hepatitis B virus (HBV). The IFN-γ/JAK2/STAT1 signaling pathway in macrophages and hepatocytes is also downregulated by KDM7A. This study provides new insights into the mechanism of HBV infection and the remodeling of the immune microenvironment.

LncRNA JHDM1D-AS1 Is a Key Biomarker for Progression and Modulation of Gemcitabine Sensitivity in Bladder Cancer Cells

Long non-coding RNAs are frequently found to be dysregulated and are linked to carcinogenesis, aggressiveness, and chemoresistance in a variety of tumors. As expression levels of the JHDM1D gene and lncRNA JHDM1D-AS1 are altered in bladder tumors, we sought to use their combined expression to distinguish between low-and high-grade bladder tumors by RTq-PCR. In addition, we evaluated the functional role of JHDM1D-AS1 and its association with the modulation of gemcitabine sensitivity in high-grade bladder-tumor cells. J82 and UM-UC-3 cells were treated with siRNA-JHDM1D-AS1 and/or three concentrations of gemcitabine (0.39, 0.78, and 1.56 µM), and then submitted to cytotoxicity testing (XTT), clonogenic survival, cell cycle progression, cell morphology, and cell migration assays. When JHDM1D and JHDM1D-AS1 expression levels were used in combination, our findings indicated favorable prognostic value. Furthermore, the combined treatment resulted in greater cytotoxicity, a decrease in clone formation, G0/G1 cell cycle arrest, morphological alterations, and a reduction in cell migration capacity in both lineages compared to the treatments alone. Thus, silencing of JHDM1D-AS1 reduced the growth and proliferation of high-grade bladder-tumor cells and increased their sensitivity to gemcitabine treatment. In addition, the expression of JHDM1D/JHDM1D-AS1 indicated potential prognostic value in the progression of bladder tumors.

Advances in Biomarkers and Endogenous Regulation of Breast Cancer Stem Cells

Breast cancer is one of the most common cancers. Even if breast cancer patients initially respond to treatment, developed resistance can lead to a poor prognosis. Cancer stem cells (CSCs) are a group of undifferentiated cells with self-renewal and multipotent differentiation characteristics. Existing evidence has shown that CSCs are one of the determinants that contribute to the heterogeneity of primary tumors. The emergence of CSCs causes tumor recurrence, metastasis, and therapeutic resistance. Previous studies indicated that different stemness-associated surface markers can identify other breast cancer stem cell (BCSC) subpopulations. Deciphering the critical signaling networks that are involved in the induction and maintenance of stemness is essential to develop novel BCSC-targeting strategies. In this review, we reviewed the biomarkers of BCSCs, critical regulators of BCSCs, and the signaling networks that regulate the stemness of BCSCs.

Circular RNA circ_IRAK3 contributes to tumor growth through upregulating KIF2A via adsorbing miR-603 in breast cancer

Background

Breast cancer (BC) threatens the health of women around the world. Researchers have proved that hsa_circ_0005505 (circ_IRAK3) facilitates BC cell invasion and migration, but the regulatory mechanisms of circ_IRAK3 in BC remain mostly unknown. We aim to explore a new mechanism by which circ_IRAK3 promotes BC progression.

Methods

Levels of circ_IRAK3, microRNA (miR)-603, and kinesin family member 2A (KIF2A) mRNA in BC tissues and cells were examined by quantitative real-time polymerase chain reaction (qRT-PCR). The cell cycle progression, colony formation, and proliferation of BC cells were evaluated by flow cytometry, plate clone, or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assays. The migration, invasion, and apoptosis of BC cells were determined by transwell or flow cytometry assays. Several protein levels were detected using western blotting. The targeting relationship between circ_IRAK3 or KIF2A and miR-603 was verified via dual-luciferase reporter assay. The role of circ_IRAK3 in vivo was verified by xenograft assay.

Results

We observed higher levels of circ_IRAK3 in BC tissues and cell lines than their respective controls. Functional experiments presented that circ_IRAK3 silencing induced BC cell apoptosis, curbed cell proliferation, migration, and invasion in vitro, and decreased tumor growth in vivo. Mechanistically, circ_IRAK3 could modulate kinesin family member 2A (KIF2A) expression through acting as a microRNA (miR)-603 sponge. miR-603 silencing impaired the effects of circ_IRAK3 inhibition on the malignant behaviors of BC cells. Also, the repressive effects of miR-603 mimic on the malignant behaviors of BC cells were weakened by KIF2A overexpression.

Conclusions

circ_IRAK3 exerted a promoting effect on BC progression by modulating the miR-603/KIF2A axis, providing a piece of novel evidence for circ_IRAK3 as a therapeutic target for BC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02497-y.

Identification of a prognostic chemoresistance-related gene signature associated with immune microenvironment in breast cancer

Breast cancer is the most common form of cancer among women globally, and chemoresistance is a major challenge to disease treatment that is associated with a poor prognosis. This study was formulated to identify a reliable prognostic biosignature capable of predicting the survival of patients with chemoresistant breast cancer (CRBC) and evaluating the associated tumor immune microenvironment. Through a series of protein-protein interaction and weighted correlation network analyses, genes that were significantly associated with breast cancer chemoresistance were identified. Moreover, univariate Cox regression and lasso-penalized Cox regression analyses were employed to generate a prognostic model, and the prognostic utility of this model was then assessed using time-dependent receiver operating characteristic (ROC) and Kaplan-Meier survival curves. Finally, The CIBERSORT and ESTIMATE algorithms were additionally leveraged to assess relationships between the tumor immune microenvironment and patient prognostic signatures. Overall, a multigenic prognostic biosignature capable of predicting CRBC patient risk was successfully developed based on bioinformatics analysis and in vitro experiments. This biosignature was able to stratify CRBC patients into high- and low-risk subgroups. ROC curves also revealed that this biosignature achieved high diagnostic efficiency, and multivariate regression analyses indicated that this risk signature was an independent risk factor linked to CRBC patient outcomes. In addition, this signature was associated with the infiltration of the tumor microenvironment by multiple immune cell types. In conclusion, the chemoresistance-associated prognostic gene signature developed herein was able to effectively evaluate the prognosis of CRBC patients and to reflect the overall composition of the tumor immune microenvironment.

Hsa_circ_002178 Promotes the Growth and Migration of Breast Cancer Cells and Maintains Cancer Stem-like Cell Properties Through Regulating miR-1258/KDM7A Axis

Breast cancer (BrCa) is the most common malignancy in women. Accumulating evidence demonstrated that abnormal circRNA expression is associated with the occurrence and progression of tumors. We analyzed the GSE101123 data and found that the expression of hsa_circ_002178 (circ_002178) was significantly increased in BrCa tissues. However, the role and possible underlying mechanisms of circ_002178 in BrCa still remain unrevealed. In this investigation, the expression levels of circ_002178 in cancer tissues or BrCa cells were significantly upregulated compared with those in paracancer tissues or normal cells. High expression of circ_002178 was correlated with the low survival rate, clinical tumor size, lymph node metastasis, and tumor, nodes, and metastases grade. After microsphere culture, the expression of circ_002178 in SUM149PT and MDA-MB-231 cells was significantly increased. Further investigation exhibited that overexpression of circ_002178 contributed to the formation of microspheres, the elevated protein levels of stemness marker, and the increased activity of ALDH1 in SUM149PT cells. Besides, the overexpression of circ_002178 also significantly promoted the growth, invasion, and migration of BrCa cells. Correspondingly, the knockdown of circ_002178 showed the opposite result in MDA-MB-231 cells. Hsa_circ_002178 was further proved to downregulate the level of miR-1258 and reduce the inhibitory effect of miR-1258 on KDM7A, thus regulating the stem-like characteristics of BrCa cells and promoting the growth and migration of BrCa cells. Taken together, targeting the circ_002178/miR-1258/KDM7A axis may be a prospective strategy for the diagnosis and therapies of BrCa in the future.

Therapeutic potential of Liuwei Dihuang pill against KDM7A and Wnt/β-catenin signaling pathway in diabetic nephropathy-related osteoporosis

The effects of Liuwei Dihuang pill (LWDH) on diabetic nephropathy-related osteoporosis (DNOP) are unclear. The present study aimed to evaluate the effects of LWDH on KDM7A and Wnt/β-catenin signaling pathway in DNOP rats and the high glucose-induced MC3T3-E1 cells. A DNOP model was prepared by streptozotocin in 9-week-old male Sprague-Dawley (SD) rats to evaluate the effects of LWDH. The cell viability and differentiation capacity of high glucose-induced MC3T3-E1 cells were determined by CCK-8 assay, Alizarin Red staining, and alkaline phosphatase (ALP) staining, respectively. Furthermore, the expressions of KDM7A and Wnt1/β-catenin pathway-related proteins were determined by Western blot analysis. Treatment of DNOP rats with LWDH could significantly ameliorate the general state, degradation of renal function, and renal pathological changes. LWDH decreased the levels of TNF-α, IL-6, IL-8, IL-1β, ALP, and TRAP, and increased the calcium, phosphorus in serum, as well as decreased the level of the calcium and phosphorus in the urine. Besides, LWDH significantly improved bone mineral density (BMD), bone volume (BV), and the bone microstructure of DNOP rats. Moreover, LWDH increased the levels of the elastic modulus, ultimate load, and bending strength in the femurs. In MC3T3-E1 cells, serum-containing LWDH significantly increases in cell viability and osteoblastic differentiation capability. The expression of α-SMA, vimentin, KDM7A, Wnt1 and β-catenin were significantly down-regulated, and the E-cadherin, H3K9-Me2, H3K27-Me2, BMP-4, BMP-7, Runx2, osteocalcin, and Col1a1 were significantly up-regulated with LWDH treatment. The present study shows that LWDH has a therapeutic effect on DNOP, in part, through down-regulation of KDM7A and Wnt/β-catenin pathway.

MYC Regulates PHF8, Which Promotes the Progression of Gastric Cancer by Suppressing miR-22-3p

Plant homeodomain finger protein 8 (PHF8) has been reported to participate in cancer development and metastasis of various types of tumors. However, little is known about the functional mechanism of PHF8 in gastric cancer (GC). This study aimed to explore the PHF8 expression pattern and function, and the role of the MYC/miRNA/PHF8 axis in GC. PHF8 expression was upregulated in GC tissues and cells as measured using quantitative reverse transcription polymerase chain reaction and western blotting. PHF8 knockdown suppressed the proliferation, migration, and invasion of GC cells, as determined using the CCK-8 assay and Transwell assay. MicroRNA-22-3p targeted PHF8, as verified by a dual-luciferase reporter assay. MYC upregulated the protein expression of PHF8 but had no effect on PHF8 mRNA expression. MYC regulates PHF8 by affecting the stability of miR-22-3p. We identified a novel MYC/miR-22-3p/PHF8 regulatory axis in GC. Therefore, PHF8 may provide a new therapeutic target for patients with GC.

Histone Demethylase KDM4C Is Required for Ovarian Cancer Stem Cell Maintenance

Ovarian cancer is a highly deadly disease, which is often diagnosed at a late stage with metastases. However, most ovarian cancers relapse after surgery combined with platinum-based chemotherapy. Cancer stem cells (CSCs) are stem-like cells that possess high tumorigenic capability and display higher resistant capability against current therapies. However, our knowledge of ovarian CSCs and their molecular mechanism remains sparse. In the current study, we found that KDM4C, a histone demethylase, was required for ovarian cancer stem cell (CSC) maintenance. Depletion of KDM4C significantly reduced the CSC population and sphere formation in vitro. Moreover, we found that KDM4C can regulate the expression of stem cell factor OCT-4 via binding to its promoter. These data indicate that KDM4C is relevant for ovarian CSC maintenance and underscore its importance as a potential therapeutic target.

Epigenetic and breast cancer therapy: Promising diagnostic and therapeutic applications

The global burden of breast cancer (BC) is increasing significantly. This trend is caused by several factors such as late diagnosis, limited treatment options for certain BC subtypes, drug resistance which all lead to poor clinical outcomes. Recent research has reported the role of epigenetic alterations in the mechanism of BC pathogenesis and its hallmarks include drug resistance and stemness features. The understanding of these modifications and their significance in the management of BC carcinogenesis is challenging and requires further attention. Nevertheless, it promises to provide novel insight needed for utilizing these alterations as potential diagnostic, prognostic markers, predict treatment efficacy, as well as therapeutic agents. This highlights the importance of continuing research development to further advance the existing knowledge on epigenetics and BC carcinogenesis to overcome the current challenges. Hence, this review aims to shed light and discuss the current state of epigenetics research in the diagnosis and management of BC.

Histone Demethylase KDM7A Regulates Androgen Receptor Activity, and Its Chemical Inhibitor TC-E 5002 Overcomes Cisplatin-Resistance in Bladder Cancer Cells

Histone demethylase KDM7A regulates many biological processes, including differentiation, development, and the growth of several cancer cells. Here, we have focused on the role of KDM7A in bladder cancer cells, especially under drug-resistant conditions. When the KDM7A gene was knocked down, bladder cancer cell lines showed impaired cell growth, increased cell death, and reduced rates of cell migration. Biochemical studies revealed that KDM7A knockdown in the bladder cancer cells repressed the activity of androgen receptor (AR) through epigenetic regulation. When we developed a cisplatin-resistant bladder cancer cell line, we found that AR expression was highly elevated. Upon treatment with TC-E 5002, a chemical inhibitor of KDM7A, the cisplatin-resistant bladder cancer cells, showed decreased cell proliferation. In the mouse xenograft model, KDM7A knockdown or treatment with its inhibitor reduced the growth of the bladder tumor. We also observed the upregulation of KDM7A expression in patients with bladder cancer. The findings suggest that histone demethylase KDM7A mediates the growth of bladder cancer. Moreover, our findings highlight the therapeutic potential of the KMD7A inhibitor, TC-E 5002, in patients with cisplatin-resistant bladder cancer.

SETDB2 promoted breast cancer stem cell maintenance by interaction with and stabilization of ΔNp63α protein

The histone H3K9 methyltransferase SETDB2 is involved in cell cycle dysregulation in acute leukemia and has oncogenic roles in gastric cancer. In our study, we found that SETDB2 plays essential roles in breast cancer stem cell maintenance. Depleted SETDB2 significantly decreased the breast cancer stem cell population and mammosphere formation in vitro and also inhibited breast tumor initiation and growth in vivo. Restoring SETDB2 expression rescued the defect in breast cancer stem cell maintenance. A mechanistic analysis showed that SETDB2 upregulated the transcription of the ΔNp63α downstream Hedgehog pathway gene. SETDB2 also interacted with and methylated ΔNp63α, and stabilized ΔNp63α protein. Restoring ΔNp63α expression rescued the breast cancer stem cell maintenance defect which mediated by SETDB2 knockdown. In conclusion, our study reveals a novel function of SETDB2 in cancer stem cell maintenance in breast cancer.