Silencing UHRF1 Enhances Radiosensitivity of Esophageal Squamous Cell Carcinoma by Inhibiting the PI3K/Akt/mTOR Signaling Pathway

Globular adiponectin induces esophageal adenocarcinoma cell pyroptosis via the miR-378a-3p/UHRF1 axis

BACKGROUND

Antiapoptosis is a major factor in the resistance of tumor cells to chemotherapy and radiotherapy. Thus, activation of cell pyroptosis may be an effective option to deal with antiapoptotic cancers such as esophageal adenocarcinoma (EAC).

METHODS

Differential expression of ubiquitin-like versus PHD and ring finger structural domain 1 (UHRF1) in EAC and near normal tissues was analyzed, as well as the prognostic impact on survival in EAC. Also, the same study was done for globular adiponectin (gAD). Simultaneously, the mRNA expression of UHRF1 was observed in different EAC cell lines. Real time cellular analysis (RTCA) was used to detect cell proliferation, and flow cytometry and inverted fluorescence microscopy were used to detect pyroptosis. Biocredit analysis was conducted to observe the correlation between UHRF1 and key pyroptosis proteins. OD values and CCK8 assay were used to determine the effect of miR-378a-3p on EAC cells. Quantitative real-time polymerase chain reaction and Western blot were used to detect the correlation between UHRF1, gAD, and miR-378a-3p in EAC cells. Moreover, in vivo and in vitro experiments were performed to detect the relevant effects on tumor migration and invasion after inhibiting UHRF1 expression.

RESULTS

UHRF1 was negatively correlated with the survival of patients with EAC, while miR-378a-3p showed the opposite effect. Additionally, gAD promoted EAC cell pyroptosis, upregulated miR-378a-3p, and significantly inhibited the proliferation of EAC cells. gAD directly reduced UHRF1 expression in EAC cells by upregulating miR-378a-3p. In cell migration and invasion assays, inhibition of UHRF1 expression significantly suppressed EAC cell metastasis. In animal experiments, we again demonstrated that gAD induced pyroptosis in EAC cells by inhibiting the expression of UHRF1.

CONCLUSION

gAD-induced upregulation of miR-378a-3p significantly inhibited the proliferation of EAC by targeting UHRF1. Therefore, gAD may serve as an alternative therapy for chemotherapy- and radiation-refractory EAC or other cancers with the same mechanism of pyroptosis action.

Etomidate suppresses proliferation, migration, invasion, and glycolysis in esophageal cancer cells via PI3K/AKT pathway inhibition

Esophageal cancer remains a formidable challenge in oncology, characterized by its poor prognosis and limited therapeutic options. Recent investigations have unveiled the potential of repurposing existing drugs for cancer treatment. Notably, etomidate, an anesthetic agent traditionally used for inducing general anesthesia, has emerged as a promising candidate demonstrating significant anticancer properties across various tumor types. The present study aims to investigate the effects of etomidate on esophageal carcinoma cells, with a specific focus on its ability to modulate the PI3K/AKT signaling pathway and inhibit tumor proliferation. This study employed both in vitro and in vivo methodologies to assess the effects of etomidate on esophageal cancer cells. In vitro experiments evaluated the effects of etomidate on cell proliferation, migration, invasion, and glycolytic processes. An in vivo xenograft mouse model was established to investigate the therapeutic potential of etomidate on tumor growth and assess its impact on the PI3K/AKT signaling pathway in a physiologically relevant context. Etomidate demonstrated a significant inhibitory effect on the proliferation, migration, invasion, and glycolytic capacity of esophageal cancer cells. This multifaceted suppression of tumorigenic properties was closely associated with the inhibition of the PI3K/AKT pathway, as evidenced by reduced phosphorylation levels of PI3K and AKT. In vivo studies using a murine model of esophageal cancer corroborated these findings. Etomidate administration resulted in a substantial reduction in tumor volume and mass, accompanied by increased apoptotic activity and the inhibition of the PI3K/AKT pathway within the tumor tissue. This study demonstrates etomidate's potent inhibition of esophageal cancer progression through suppression of the PI3K/AKT pathway. These promising results warrant further clinical investigation of etomidate as a potential therapeutic strategy for esophageal cancer.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-024-00661-y.

DNMT1-driven methylation of RORA facilitates esophageal squamous cell carcinoma progression under hypoxia through SLC2A3

BACKGROUND

The RAR-related orphan receptor alpha (RORA), a circadian clock molecule, is highly associated with anti-oncogenes. In this paper, we defined the precise action and mechanistic basis of RORA in ESCC development under hypoxia.

METHODS

Expression analysis was conducted by RT-qPCR, western blotting, immunofluorescence (IF), and immunohistochemistry (IHC) assays. The functions of RORA were assessed by detecting its regulatory effects on cell viability, motility, invasion, and tumor growth. DNA pull-down assay and proteomic analysis were employed to identify proteins bound to the RORA promoter. The promoter methylation level of RORA was detected by DNA pyrosequencing. RNA-seq analysis was performed to explore the downstream mechanisms of RORA, and the transcriptional regulation of RORA on SLC2A3 was verified by ChIP-qPCR and dual-luciferase reporter assay. Glycolysis was assessed by detecting the consumption of glucose and the production of lactic acid and ATP.

RESULTS

In vitro, RORA was shown to suppress ESCC cell viability, motility, and invasion under hypoxic condition. In vivo, increased RORA expression in mouse xenografts impeded tumor growth. DNMT1 was identified to widely exist in the RORA promoter, increasing DNA methylation and reducing RORA expression in hypoxia-induced KYSE150 ESCC cells. Mechanistically, RORA was found to inactivate the transcription of glucose transporter protein SLC2A3 by interacting with its promoter F1 region. Furthermore, rescue experiments revealed that RORA-mediated suppressive effects on ESCC cell migration and invasion were largely based on its negative regulation of SLC2A3 and glycolysis.

CONCLUSION

DNMT1-driven methylation of RORA promotes ESCC progression largely through affecting SLC2A3 transcription and glycolysis. These findings turn RORA into potential target of anti-cancer therapeutic agents.

UHRF1 knockdown induces cell cycle arrest and apoptosis in breast cancer cells through the ZBTB16/ANXA7/Cyclin B1 axis

Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) is involved in tumorigenicity through DNA methylation in various cancers, including breast cancer. This study aims to investigate the regulatory mechanisms of UHRF1 in breast cancer progression. Herein, we show that UHRF1 is upregulated in breast cancer tissues and cell lines as measured by western blot analysis and immunohistochemistry. Breast cancer cells are transfected with a UHRF1 overexpression plasmid (pcDNA-UHRF1) or short hairpin RNA targeting UHRF1 (sh-UHRF1), followed by detection of cell proliferation, invasion, apoptosis, and cell cycle. UHRF1 overexpression promotes proliferation and invasion and attenuates cell cycle arrest and apoptosis in breast cancer cells, while UHRF1 knockdown shows the opposite effect. Moreover, methylation-specific PCR and ChIP assays indicate that UHRF1 inhibits zinc finger and BTB domain containing 16 (ZBTB16) expression by promoting ZBTB16 promoter methylation via the recruitment of DNA methyltransferase 1 (DNMT1). Then, a co-IP assay is used to verify the interaction between ZBTB16 and the annexin A7 (ANXA7) protein. ZBTB16 promotes ANXA7 expression and subsequently inhibits Cyclin B1 expression. Rescue experiments reveal that ZBTB16 knockdown reverses the inhibitory effects of UHRF1 knockdown on breast cancer cell malignancies and that ANXA7 knockdown abolishes the inhibitory effects of ZBTB16 overexpression on breast cancer cell malignancies. Additionally, UHRF1 knockdown significantly inhibits xenograft tumor growth in vivo. In conclusion, UHRF1 knockdown inhibits proliferation and invasion, induces cell cycle arrest and apoptosis in breast cancer cells via the ZBTB16/ANXA7/Cyclin B1 axis, and reduces xenograft tumor growth in vivo.

Deciphering the dual roles of PHD finger proteins from oncogenic drivers to tumor suppressors

PHD (plant homeodomain) finger proteins emerge as central epigenetic readers and modulators in cancer biology, orchestrating a broad spectrum of cellular processes pivotal to oncogenesis and tumor suppression. This review delineates the dualistic roles of PHD fingers in cancer, highlighting their involvement in chromatin remodeling, gene expression regulation, and interactions with cellular signaling networks. PHD fingers' ability to interpret specific histone modifications underscores their influence on gene expression patterns, impacting crucial cancer-related processes such as cell proliferation, DNA repair, and apoptosis. The review delves into the oncogenic potential of certain PHD finger proteins, exemplified by PHF1 and PHF8, which promote tumor progression through epigenetic dysregulation and modulation of signaling pathways like Wnt and TGFβ. Conversely, it discusses the tumor-suppressive functions of PHD finger proteins, such as PHF2 and members of the ING family, which uphold genomic stability and inhibit tumor growth through their interactions with chromatin and transcriptional regulators. Additionally, the review explores the therapeutic potential of targeting PHD finger proteins in cancer treatment, considering their pivotal roles in regulating cancer stem cells and influencing the immune response to cancer therapy. Through a comprehensive synthesis of current insights, this review underscores the complex but promising landscape of PHD finger proteins in cancer biology, advocating for further research to unlock novel therapeutic avenues that leverage their unique cellular roles.

Mechanisms of radiotherapy resistance and radiosensitization strategies for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the sixth most common cause of cancer-related mortality worldwide, with more than half of them occurred in China. Radiotherapy (RT) has been widely used for treating ESCC. However, radiation-induced DNA damage response (DDR) can promote the release of cytokines and chemokines, and triggers inflammatory reactions and changes in the tumor microenvironment (TME), thereby inhibiting the immune function and causing the invasion and metastasis of ESCC. Radioresistance is the major cause of disease progression and mortality in cancer, and it is associated with heterogeneity. Therefore, a better understanding of the radioresistance mechanisms may generate more reversal strategies to improve the cure rates and survival periods of ESCC patients. We mainly summarized the possible mechanisms of radioresistance in order to reveal new targets for ESCC therapy. Then we summarized and compared the current strategies to reverse radioresistance.

Natural and Synthetic Anticancer Epidrugs Targeting the Epigenetic Integrator UHRF1

Cancer is one of the leading causes of death worldwide, and its incidence and mortality are increasing each year. Improved therapeutic strategies against cancer have progressed, but remain insufficient to invert this trend. Along with several other risk factors, abnormal genetic and epigenetic regulations play a critical role in the initiation of cellular transformation, as well as tumorigenesis. The epigenetic regulator UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1) is a multidomain protein with oncogenic abilities overexpressed in most cancers. Through the coordination of its multiple domains and other epigenetic key players, UHRF1 regulates DNA methylation and histone modifications. This well-coordinated dialogue leads to the silencing of tumor-suppressor genes (TSGs) and facilitates tumor cells' resistance toward anticancer drugs, ultimately promoting apoptosis escape and uncontrolled proliferation. Several studies have shown that the downregulation of UHRF1 with natural compounds in tumor cells induces the reactivation of various TSGs, inhibits cell growth, and promotes apoptosis. In this review, we discuss the underlying mechanisms and the potential of various natural and synthetic compounds that can inhibit/minimize UHRF1's oncogenic activities and/or its expression.

The transcription factor HBP1 promotes ferroptosis in tumor cells by regulating the UHRF1-CDO1 axis

The induction of ferroptosis in tumor cells is one of the most important mechanisms by which tumor progression can be inhibited; however, the specific regulatory mechanism underlying ferroptosis remains unclear. In this study, we found that transcription factor HBP1 has a novel function of reducing the antioxidant capacity of tumor cells. We investigated the important role of HBP1 in ferroptosis. HBP1 down-regulates the protein levels of UHRF1 by inhibiting the expression of the UHRF1 gene at the transcriptional level. Reduced levels of UHRF1 have been shown to regulate the ferroptosis-related gene CDO1 by epigenetic mechanisms, thus up-regulating the level of CDO1 and increasing the sensitivity of hepatocellular carcinoma and cervical cancer cells to ferroptosis. On this basis, we constructed metal-polyphenol-network coated HBP1 nanoparticles by combining biological and nanotechnological. MPN-HBP1 nanoparticles entered tumor cells efficiently and innocuously, induced ferroptosis, and inhibited the malignant proliferation of tumors by regulating the HBP1-UHRF1-CDO1 axis. This study provides a new perspective for further research on the regulatory mechanism underlying ferroptosis and its potential role in tumor therapy.

Plumbagin downregulates UHRF1, p-Akt, MMP-2 and suppresses survival, growth and migration of cervical cancer CaSki cells

Plumbagin is a natural compound known to impede growth of cancerous cells. However, anti-cervical cancer effects of plumbagin and its underlying molecular mechanism still remains elusive. In this study, plumbagin reduced the viability of CaSki cells in a concentration dependent manner and suppressed their colony formation potential. It led to G2/M phase arrest with downregulation of E2F1 and upregulation of p21. Plumbagin reduced mitochondrial membrane potential and concomitantly increased the percentage of apoptotic cells as revealed by annexin V-propidium iodide staining. Real Time PCR and western blotting confirmed that plumbagin induced apoptosis by reducing the expression of pAkt, procaspase 9 and full-length PARP. Furthermore, scratch assay showed that plumbagin suppressed migratory potential of CaSki cells which could be due to the reduced expression and activity of MMP-2 and upregulation of TIMP2. Interestingly, plumbagin also downregulated UHRF1 expression. Transient silencing of UHRF1 like plumbagin, induced G2/M phase arrest, enhanced apoptosis and suppressed metastasis of CaSki cells suggesting the role of UHRF1 in mediating anti-cancer activities of plumbagin. Plumbagin at IC₂₀ (1 μM) interacted synergistically with cisplatin and reduced its IC₅₀ value by 13.23 fold with improved effectivity as revealed by augmented apoptosis in CaSki cells.

Irradiation-induced exosomal HMGB1 to confer radioresistance via the PI3K/AKT/FOXO3A signaling pathway in ESCC

Background

Radioresistance is a major cause of treatment failure in esophageal squamous cell carcinoma (ESCC) radiotherapy, and the underlying mechanisms of radioresistance are still unclear. Irradiation (IR) stimulates changes in tumor-derived exosome contents, which can be taken up by recipient cells, playing an important role in the proliferation, cell cycle and apoptosis of recipient cells. This study investigated the effect of IR-induced exosomal high mobility group box 1 (HMGB1) on radioresistance in ESCC cells.

Methods

Plasma exosomes were isolated from 21 ESCC patients and 24 healthy volunteers, and the expression of HMGB1 was examined. Then, the therapeutic effect of radiotherapy was analyzed according to the different expression levels of plasma exosomal HMGB1 in ESCC patients. The uptake of exosomes by recipient cells was verified by immunofluorescence staining, and the localization of exosomes and HMGB1 in cells before and after IR was evaluated. The effects of IR-induced exosomes on cell proliferation, invasion, apoptosis, cell cycle distribution and radioresistance after HMGB1 knockdown were verified. Moreover, western blotting was used to measure changes in the expression of cyclin B1, CDK1, Bax, Bcl2, phosphorylated histone H2AX and the PI3K/AKT/FOXO3A pathway in the HMGB1-knockdown exosome group and the negative control group.

Results

The expression of HMGB1 in ESCC plasma exosomes was significantly increased compared with that in healthy volunteers, and high expression of HMGB1 in plasma exosomes was associated with radioresistance (P = 0.016). IR-induced the release of exosomal HMGB1 and promoted proliferation and radioresistance in recipient cells, with a sensitization enhancement ratio (SER) of 0.906 and 0.919, respectively. In addition, IR-induced exosomal HMGB1 promotes G2/M phase arrest by regulating the proteins cyclin B1 and CDK1, cooperating with the proteins Bax and Bcl2 to reduce the apoptosis rate through the PI3K/AKT/FOXO3A signaling pathway, and participated in IR-induced DNA damage repair through γH2AX.

Conclusion

These findings indicate that high expression of plasma exosomal HMGB1 is associated with an adverse radiotherapy response. IR-induced exosomal HMGB1 enhances the radioresistance of ESCC cells.

Roles of PTEN inactivation and PD-1/PD-L1 activation in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the most common type of esophageal cancer in China and developing countries. The purpose of this review is to summarize the roles of inactivation of the tumor suppressor gene, phosphatase and tensin homolog (PTEN), and activation of the programmed cell death protein 1 (PD-1) upon binding to its ligand (PD-L1) in the promotion of ESCC. Studies of ESCC performed in vitro and in vivo indicated that PTEN and PD-L1 function in the regulation of cell proliferation, invasion, and migration; the epithelial-mesenchymal transition; resistance to chemotherapy and radiotherapy; and the PI3K/AKT signaling pathway. Certain genetic variants of PTEN are related to susceptibility to ESCC, and PTEN and PD-L1 also function in ESCC progression and affect the prognosis of patients with ESCC. There is also evidence that the expression of PD-L1 and PTEN are associated with the progression of certain other cancers. Future studies should further examine the relationship of PD-L1 and PTEN and their possible interactions in ESCC.