ZHX2 inhibits proliferation and promotes apoptosis of human lung cancer cells through targeting p38MAPK pathway

Von Hippel-Lindau protein signalling in clear cell renal cell carcinoma

The distinct pathological and molecular features of kidney cancer in adaptation to oxygen homeostasis render this malignancy an attractive model for investigating hypoxia signalling and potentially developing potent targeted therapies. Hypoxia signalling has a pivotal role in kidney cancer, particularly within the most prevalent subtype, known as renal cell carcinoma (RCC). Hypoxia promotes various crucial pathological processes, such as hypoxia-inducible factor (HIF) activation, angiogenesis, proliferation, metabolic reprogramming and drug resistance, all of which contribute to kidney cancer development, growth or metastasis formation. A substantial portion of kidney cancers, in particular clear cell RCC (ccRCC), are characterized by a loss of function of Von Hippel-Lindau tumour suppressor (VHL), leading to the accumulation of HIF proteins, especially HIF2α, a crucial driver of ccRCC. Thus, therapeutic strategies targeting pVHL-HIF signalling have been explored in ccRCC, culminating in the successful development of HIF2α-specific antagonists such as belzutifan (PT2977), an FDA-approved drug to treat VHL-associated diseases including advanced-stage ccRCC. An increased understanding of hypoxia signalling in kidney cancer came from the discovery of novel VHL protein (pVHL) targets, and mechanisms of synthetic lethality with VHL mutations. These breakthroughs can pave the way for the development of innovative and potent combination therapies in kidney cancer.

Characterization of circSEC11A as a novel regulator of Iodine-125 radioactive seed-induced anticancer effects in hepatocellular carcinoma via targeting ZHX2/GADD34 axis

Iodine-125 (I-125) radioactive seed implantation is used for the local treatment of hepatocellular carcinoma (HCC), but the molecular mechanisms regulating its anticancer effects remain incompletely understood. In this study, we report that hsa_circ_0000647 (circSEC11A) is highly expressed after I-125 treatment in HCC cell lines and tissues and is a key regulator of I-125-induced anticancer effects. CircSEC11A acts as a competing endogenous RNA (ceRNA) to sponge miR-3529-3p, promoting the expression of zinc fingers and homeoboxes 2 (ZHX2) and enhancing I-125-induced anticancer effects. Dual-luciferase reporter assay, RNA pull-down, RNA immunoprecipitation, and fluorescence in situ hybridization were thereafter performed to verify the interaction among the molecules. Anticancer effects were detected using CCK-8, flow cytometry, TUNEL, EdU, transwell, and wound healing assays. Furthermore, ZHX2 transcriptionally inhibits GADD34, a negative regulator of endoplasmic reticulum stress (ERS), to enhance I-125- induced anticancer effects in vivo and in vitro. In conclusion, we characterized circSEC11A as a novel regulator of I-125-induced anticancer effects in HCC via miR-3529-3p/ZHX2/GADD34 axis-mediated ERS. Thus, circSEC11A may act as a potential therapeutic target for I-125 implantation in the clinic.

Zhx2 maintains islet β-cell mass and function by transcriptionally regulating Pax6

Emerging evidence shows that pancreatic β-cell function and quality are key determinants in the progression of type 2 diabetes (T2D). The transcription factor zinc finger homeobox 2 (Zhx2) is involved in proliferation and development of multiple cells. However, the exact role of Zhx2 in β-cells and T2D remains completely unknown. Here, we report that Zhx2 orchestrates β-cell mass and function by regulating paired box protein pax-6 (Pax6). We found that β-cell-specific knockout Zhx2 (Zhx2BKO) mice showed a decrease in β-cell proliferation and glucose homeostasis. Under prediabetic and diabetic conditions, we discovered glucose intolerance in both Zhx2BKO-HFD mice and Zhx2BKO-db/db mice, with reduced β-cell mass and insulin secretion. Mechanistically, we demonstrated that Zhx2 targeted the Pax6 promoter region (-1740∼-1563; -862∼-559; -251∼+75), enhanced promoter activity. Overall, Zhx2 maintains β-cell function by transcriptionally regulating Pax6, which provides a therapeutic target for diabetes intervention.

Identification of Glucocorticoid Receptor Target Genes That Potentially Inhibit Collagen Synthesis in Human Dermal Fibroblasts

Over several decades, excess glucocorticoids (GCs) of endogenous or exogenous origin have been recognized to significantly inhibit collagen synthesis and accelerate skin aging. However, little is known regarding their molecular mechanisms. We hypothesized that the action of GCs on collagen production is at least partially through the glucocorticoid receptor (GR) and its target genes, and therefore aimed to identify GR target genes that potentially inhibit collagen synthesis in Hs68 human dermal fibroblasts. We first confirmed that dexamethasone, a synthetic GC, induced canonical GR signaling in dermal fibroblasts. We then collected 108 candidates for GR target genes reported in previous studies on GR target genes and verified that 17 genes were transcriptionally upregulated in dexamethasone-treated dermal fibroblasts. Subsequently, by individual knockdown of the 17 genes, we identified that six genes, AT-rich interaction domain 5B, FK506 binding protein 5, lysyl oxidase, methylenetetrahydrofolate dehydrogenase (NADP + dependent) 2, zinc finger protein 36, and zinc fingers and homeoboxes 3, are potentially involved in GC-mediated inhibition of collagen synthesis. The present study sheds light on the molecular mechanisms of GC-mediated skin aging and provides a basis for further research on the biological characteristics of individual GR target genes.

Cell-in-cell promotes lung cancer malignancy by enhancing glucose metabolism through mitochondria transfer

Heterotypic cell-in-cell structure (CICs) is the definition of the entry of one type of living cells into another type of cell. CICs between immune cells and tumor cells have been found to correlate with malignancy in many cancers. Since tumor immune microenvironment promotes non-small cell lung cancer (NSCLC) progression and drug resistance, we wondered the potential significance of heterotypic CICs in NSCLC. Heterotypic CICs was analyzed by histochemistry in an expanded spectrum of clinical lung cancer tissue specimens. In vitro study was performed using the mouse lung cancer cell line LLC and splenocytes. Our results revealed that CICs formed by lung cancer cells and infiltrated lymphocytes were correlated with malignancy of NSCLC. In addition, we found CICs mediated the transfer of lymphocyte mitochondria to tumor cells, and promoted cancer cell proliferation and anti-cytotoxicity by activating MAPK pathway and up-regulating PD-L1 expression. Furthermore, CICs induces glucose metabolism reprogramming of lung cancer cells by upregulating glucose intake and glycolytic enzyme. Our findings suggest that CICs formed by lung cancer cell and lymphocyte contribute to NSCLC progression and reprogramming of glucose metabolism, and might represent a previously undescribed pathway for drug resistance of NSCLC.

ZHX2 in health and disease

As a transcriptional factor and the negative regulator of alpha fetal protein (AFP), Zinc fingers and homeoboxes 2 (ZHX2) has a well-established role in protection against hepatocellular carcinoma (HCC). However, recent studies have suggested ZHX2 as an oncogene in clear cell renal cell carcinoma (ccRCC) and triple-negative breast cancer (TNBC). Moreover, mounting evidence has illustrated a much broader role of ZHX2 in multiple cellular processes, including cell proliferation, cell differentiation, lipid metabolism, and immunoregulation. This comprehensive review emphasizes the role of ZHX2 in health and diseases which have been more recently uncovered.

Zinc Fingers and Homeobox Family in Cancer: A Double-Edged Sword

The zinc fingers and homeobox (ZHX) family includes ZHX1, ZHX2, and ZHX3, and their proteins have similar unique structures, containing two C2H2-type zinc finger motifs and four or five HOX-like homeodomains. The members of the ZHX family can form homodimers or heterodimers with each other or with a subunit of nuclear factor Y. Previous studies have suggested that ZHXs can function as positive or negative transcriptional regulators. Recent studies have further revealed their biological functions and underlying mechanisms in cancers. This review summarized the advances of ZHX-mediated functions, including tumor-suppressive and oncogenic functions in cancer formation and progression, the molecular mechanisms, and regulatory functions, such as cancer cell proliferation, migration, invasion, and metastasis. Moreover, the differential expression levels and their association with good or poor outcomes in patients with various malignancies and differential responses to chemotherapy exert opposite functions of oncogene or tumor suppressors. Therefore, the ZHXs act as a double-edged sword in cancers.

EZH2 affects malignant progression and DNA damage repair of lung adenocarcinoma cells by regulating RAI2 expression

BACKGROUND

Lung adenocarcinoma (LUAD) is featured in high morbidity and mortality. Aberrant activation of the histone methyltransferase EZH2 has close association with cancer progression. This research aimed to deeply dive into the role and possible molecular mechanisms of EZH2 and its downstream genes in malignant progression and DNA damage repair of LUAD cells.

METHODS

Expression of EZH2 in LUAD cells was analyzed by qRT-PCR, and the effects of EZH2 on proliferation, and apoptosis of LUAD cells were examined by CCK-8, colony formation and flow cytometry assays. The downstream targets of EZH2 were predicted by bioinformatics analysis. Then, the targeting relationship between EZH2 and RAI2 was examined by CHIP and luciferase reporter assays. Rescue assay were used to further validate the effect of EZH2/RAI2 on the malignant progression of LUAD cells. The expression levels of EZH2, RAI2 and p53 were examined by Western blot.

RESULTS

Upregulation of EZH2 was identified in LUAD tissues and cells. RAI2 was a downstream target gene of EZH2, and the two were negatively correlated. Silencing EZH2 suppressed proliferation of LUAD cells, promoted expression of p53, cell cycle arrest and apoptosis. While silencing RAI2 could reverse the above-mentioned effects caused by EZH2 silencing.

CONCLUSION

These results demonstrated that EZH2 promoted malignant progression and DNA damage repair of LUAD cells by targeting and negatively regulating RAI2.

ZHX2 inhibits thyroid cancer metastasis through transcriptional inhibition of S100A14

Background

Thyroid cancer is the most common malignant endocrine tumour, and metastasis has become the main reason for treatment failure. However, the underlying molecular mechanism of thyroid cancer metastasis remains poorly understood. We investigated the role of the tumour suppressor zinc fingers and homeoboxes 2 (ZHX2) in the metastasis of thyroid cancer.

Methods

To study the role of ZHX2 in thyroid cancer metastasis, we evaluated the EMT process using cell migration, wound healing and lung metastatic tumour formation in vitro and in vivo models.

Results

ZHX2 expression was significantly decreased in thyroid cancer tissues, which correlated with poor prognosis of thyroid cancer patients. ZHX2 knockdown significantly promoted the migration of thyroid cancer cells. Mechanistically, ZHX2 associated with the S100 calcium binding protein A14 (S100A14) promoter to decrease the transcription of S100A14. Moreover, S100A14 was highly expressed in human thyroid cancer samples, and its expression negatively correlated with ZHX2 expression.

Conclusions

Inhibition of S100A14 attenuated the ZHX2 knockdown-induced enhanced metastasis of thyroid cancer cells both in vitro and in vivo. The evidence presented here suggests that ZHX2 inhibits the progression of thyroid cancer by blocking S100A14-mediated metastasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02499-w.

STAT3 but Not STAT5 Contributes to the Protective Effect of Electroacupuncture Against Myocardial Ischemia/Reperfusion Injury in Mice

Electroacupuncture (EA) can help reduce infarct size and injury resulting from myocardial ischemia/reperfusion (I/R); however, the underlying molecular mechanism remains unknown. We previously reported that STAT5 plays a critical role in the cardioprotective effect of remote ischemic preconditioning (RIPC). Here, we assessed the effects of electroacupuncture pretreatment (EAP) on myocardial I/R injury in the presence and/or absence of Stat5 in mice and investigated whether EAP exerts its cardioprotective effects in a STAT5-dependent manner. Adult Stat5^fl/fl and Stat5-cKO mice were exposed to EAP at Neiguan (PC6) for 7 days before the induction of I/R injury by left anterior descending (LAD) coronary artery ligation. The myocardial infarct size (IS), area at risk, and apoptotic rate of cardiomyocytes were detected. RT-qPCR and western blotting were used to measure gene and protein expression, respectively, in homogenized heart tissues. RNA-seq was used to identify candidate genes and pathways. Our results showed that EAP decreased IS and the rate of cardiomyocyte apoptosis. We further found that STAT5 was activated by EAP in Stat5^fl/fl mice but not in Stat5-cKO mice, whereas the opposite was observed for STAT3. Following EAP, the levels of the antiapoptotic proteins Bcl-xL, Bcl-2, and p-AKT were increased in the presence of Stat5, while that of interleukin 10 (IL-10) was increased in both Stat5^fl/fl and Stat5-cKO. The gene expression profile in heart tissues was different between Stat5^fl/fl and the Stat5-cKO mice with EAP. Importantly, the top 30 DEGs under EAP in the Stat5-cKO mice were enriched in the IL-6/STAT3 signaling pathway. Our results revealed for the first time that the protective effect of EAP following myocardial I/R injury was attributable to, but not dependent on, STAT5. Additionally, we found that EAP could activate STAT3 signaling in the absence of the Stat5 gene, and could also activate antiapoptotic, survival, and anti-inflammatory signaling pathways.

Schisandrin B inhibits epithelial‑mesenchymal transition and stemness of large‑cell lung cancer cells and tumorigenesis in xenografts via inhibiting the NF‑κB and p38 MAPK signaling pathways

Lung cancer is one of the most common types of cancer in the world, resulting in numerous cancer‑associated deaths. The properties of cancer stem cells (CSCs) are important for the initiation and deterioration of lung cancer. Schisandrin B (SchB), an active compound extracted from Schisandra chinensis, exerts anticancer effects in various malignancies, including lung cancer. Nevertheless, the potential of SchB in epithelial‑mesenchymal transition (EMT) and CSC features of large‑cell lung cancer remains unclear. The present study established cancer stem‑like cells derived from large‑cell lung cancer cells, NCI‑H460 and H661, and revealed that SchB inhibited the viability of cancer stem‑like cells at concentrations of ≥40 µmol/l. Moreover, SchB prominently inhibited cell migration, invasion and EMT. Sphere‑forming assays and western blotting demonstrated that the stemness of cancer stem‑like cells was alleviated by SchB treatment. Mechanistically, the current findings revealed that SchB contributed to the suppression of the NF‑κB and p38 MAPK signaling pathways. Notably, further results revealed that the malignant behaviors of NCI‑H460‑CSCs induced by the activation of the NF‑κB and p38 MAPK signaling pathways were suppressed by SchB treatment. Consistently, the inhibitory role of SchB in EMT and CSC activities, as well as in the activation of the NF‑κB and p38 MAPK signaling pathways, was confirmed in vivo. In conclusion, the present study demonstrated that SchB exerted inhibitory effects on large‑cell lung cancer cells via targeting the NF‑κB and p38 MAPK signaling pathways, suggesting that SchB may act as a potential therapeutic drug for large‑cell lung cancer.

Upregulation of ZHX2 predicts poor prognosis and is correlated with immune infiltration in gastric cancer

The transcriptional repressor zinc finger homeobox 2 (ZHX2) is reported to regulate tumor progression in several human cancers, although little is known about its role in gastric cancer (GC). In the present study, we investigated the expression of ZHX2 and its relationship with the clinicopathological characteristics and prognosis of GC patients, and we also examined the effect of ZHX2 overexpression in GC cell lines. We used UALCAN (http://ualcan.path.uab.edu) and the Tumor Immune Estimation Resource (http://cistrome.org/TIMER) to examine ZHX2 mRNA expression, and also used Kaplan–Meier Plotter (https://kmplot.com) to determine whether ZHX2 expression was related to GC prognosis. Expression of ZHX2 protein was detected using immunohistochemical staining assays. Cell proliferation was evaluated using a cell counting kit‐8 and colony formation assays, whereas apoptosis was examined by flow cytometry. Wound healing and transwell assays were used to detect cell migration and invasion. We also performed Gene Set Enrichment Analysis (https://www.gsea‐msigdb.org) and used The Cancer Genome Atlas database (https://www.genome.gov/Funded‐Programs‐Projects/Cancer‐Genome‐Atlas) to examine the correlation of ZHX2 with immune infiltration. We report that ZHX2 is highly expressed in GC tissues and is significantly associated with clinical characteristics. Upregulation of ZHX2 predicted poor prognosis in GC. Furthermore, ZHX2 overexpression can promote the proliferation, invasion and migration, but inhibit apoptosis, of GC cells. High expression of ZHX2 in GC is correlated with the presence of infiltrating immune cells, including B cells, CD4⁺ T cells, macrophages and dendritic cells. Our data suggest that high expression of ZHX2 in GC predicts poor prognosis. In addition, ZHX2 may promote malignant behaviors of GC cells, and immune infiltration might be related to the oncogenic role of ZHX2 in GC.

Liver Kinase B1 (LKB1) Regulates Proliferation and Apoptosis of Non-Small Cell Lung Cancer A549 Cells via Targeting ERK Signaling Pathway

Objective

To study the effect and potential mechanism of LKB1 on non-small cell lung cancer (NSCLC) A549 cells.

Material and Methods

A549 cells were divided into control group, LKB1 negative control (NC) group, LKB1 group, ERK inhibitor group and LKB1 + ERK activator group. Cell proliferation and apoptosis were detected by cell counting kit (CCK-8) assay and flow cytometry, respectively. Transwell assay was used to analyze the invasion ability of A549 cells. The expression of apoptosis and ERK signaling pathway-related proteins were studied by Western blot. Furthermore, a nude mouse xenograft model was constructed and treated with LKB1, ERK inhibitor and activator, respectively. The tumor volume and tumor weight were measured. Immunohistochemistry was used to test the expression of Ki-67 protein in tumor tissues, and TUNEL staining was used to test the apoptosis. Moreover, Western blot was used to detect ERK signaling pathway-related proteins in tumor tissues.

Results

Compared with control and NC groups, cell proliferation and invasion were inhibited in ERK inhibitor and LKB1 groups, while apoptosis and apoptosis-related proteins were increased (p < 0.05). Further study showed that ERK activator can reverse the effect of LKB1 in A549 cells. In nude mice, ERK inhibitor and LKB1 can reduce cell tumorigenicity and inhibit proliferation. Apoptosis was increased by ERK inhibitor and LKB1 treatment. Western blot showed that LKB1 and ERK inhibitor could reduce the protein expression of p-ERK1/2. However, the indicators above were the opposite in the ERK activator group.

Conclusion

LKB1 overexpression can inhibit proliferation and promote apoptosis of NSCLC A549 cells, and its mechanism may be related to inhibition of the ERK signaling pathway.

ZHX2 inhibits SREBP1c-mediated de novo lipogenesis in hepatocellular carcinoma via miR-24-3p

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Lipogenesis has been considered as a critical player in HCC initiation and progression. However, the underlying mechanism is still not fully understood. Here, we identified zinc fingers and homeoboxes 2 (ZHX2), an HCC-associated tumor suppressor, as an important repressor of de novo lipogenesis. Ectopic expression of ZHX2 significantly inhibited de novo lipogenesis in HCC cells and decreased expression of FASN, ACL, ACC1, and SCD1. In accordance with this, ZHX2 was negatively associated with SREBP1c, the master regulator of de novo lipogenesis, in HCC cell lines and human specimens. Results from silencing and overexpression demonstrated that ZHX2 inhibited de novo lipogenesis and consequent HCC progression via repression of SREBP1c. Furthermore, treatment with the SREBP1c inhibitor fatostatin dampened the spontaneous formation of tumors in liver-specific Zhx2 knockout mice. Mechanistically, ZHX2 increased expression of miR-24-3p transcriptionally, which targeted SREBP1c and led to its degradation. In conclusion, our data suggest a novel mechanism through which ZHX2 suppresses HCC progression, which may provide a new strategy for the treatment of HCC. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

ZHX2 mediates proteasome inhibitor resistance via regulating nuclear translocation of NF-κB in multiple myeloma

Background

Multiple myeloma (MM) is an incurable hematological malignancy. Although proteasome inhibitors and immunomodulators have significantly improved patient outcomes, some patients respond poorly to treatment and almost all patients will relapse. Mechanisms of proteasome inhibitor resistance in multiple myeloma have not been fully elucidated. ZHX2 is a transcription regulator degraded via proteasome and presents both oncogenic or tumor suppressive effect in different cancers, however, it is still unknown that the role of ZHX2 in myeloma. In this study, we aim to demonstrate the effect and mechanism of ZHX2 on proteasome inhibitor resistance in MM.

Methods

GSE24080 gene expression profile datasets from Gene Expression Omnibus (GEO) were analyzed to evaluate the relationship between ZHX2 expression level and survival in MM. Expression of ZHX2 in human MM cell lines at baseline and after bortezomib (BTZ) treatment was determined by Western blotting (WB). The proliferation and apoptosis rate of MM cells treated with BTZ after the knockdown of ZHX2 were analyzed by flow cytometry. Nuclear translocation of NF‐κB after the knockdown of ZHX2 was evaluated by WB and immunofluorescence, and the expression of NF‐κB target genes was measured by real‐time quantitative PCR. Co‐immunoprecipitation (Co‐IP) and WB were used to detect the interaction of ZHX2 with NF‐κB.

Results

We found that higher ZHX2 expression was correlated with poorer clinical outcomes of patients. In addition, ZHX2 expression was relatively higher in RPMI‐8226 and MM.1S cell lines and the level of ZHX2 protein was upregulated after BTZ treatment. Knockdown of ZHX2 significantly enhanced the sensitivity of MM cells to BTZ, inhibited nuclear translocation of NF‐κB, and reduced mRNA expression of NF‐κB target genes. It was also revealed that ZHX2 directly binds to NF‐κB.

Conclusion

Our study showed that ZHX2 can promote proteasome inhibitor resistance in MM cells by regulating the nuclear translocation of NF‐κB.