BIX-01294 sensitizes renal cancer Caki cells to TRAIL-induced apoptosis through downregulation of survivin expression and upregulation of DR5 expression

Inhibition of USP2 Enhances TRAIL-Mediated Cancer Cell Death through Downregulation of Survivin

Ubiquitin-specific protease 2 (USP2) is a deubiquitinase belonging to the USPs subfamily. USP2 has been known to display various biological effects including tumorigenesis and inflammation. Therefore, we aimed to examine the sensitization effect of USP2 in TRAIL-mediated apoptosis. The pharmacological inhibitor (ML364) and siRNA targeting USP2 enhanced TNF-related apoptosis-inducing ligand (TRAIL)-induced cancer cell death, but not normal cells. Mechanistically, USP2 interacted with survivin, and ML364 degraded survivin protein expression by increasing the ubiquitination of survivin. Overexpression of survivin or USP2 significantly prevented apoptosis through cotreatment with ML364 and TRAIL, whereas a knockdown of USP2 increased sensitivity to TRAIL. Taken together, our data suggested that ML364 ubiquitylates and degrades survivin, thereby increasing the reactivity to TRAIL-mediated apoptosis in cancer cells.

H3 histone methylation landscape in male urogenital cancers: from molecular mechanisms to epigenetic biomarkers and therapeutic targets

During the last decades, male urogenital cancers (including prostate, renal, bladder and testicular cancers) have become one of the most frequently encountered malignancies affecting all ages. While their great variety has promoted the development of various diagnosis, treatment and monitoring strategies, some aspects such as the common involvement of epigenetic mechanisms are still not elucidated. Epigenetic processes have come into the spotlight in the past years as important players in the initiation and progression of tumors, leading to a plethora of studies highlighting their potential as biomarkers for diagnosis, staging, prognosis, and even as therapeutic targets. Thus, fostering research on the various epigenetic mechanisms and their roles in cancer remains a priority for the scientific community. This review focuses on one of the main epigenetic mechanisms, namely, the methylation of the histone H3 at various sites and its involvement in male urogenital cancers. This histone modification presents a great interest due to its modulatory effect on gene expression, leading either to activation (e.g., H3K4me3, H3K36me3) or repression (e.g., H3K27me3, H3K9me3). In the last few years, growing evidence has demonstrated the aberrant expression of enzymes that methylate/demethylate histone H3 in cancer and inflammatory diseases, that might contribute to the initiation and progression of such disorders. We highlight how these particular epigenetic modifications are emerging as potential diagnostic and prognostic biomarkers or targets for the treatment of urogenital cancers.

The role of histone methylation in renal cell cancer: an update

Renal cell carcinoma accounts for 2-3% of all cancers. It is difficult to diagnose early. Recently, genome-wide studies have identified that histone methylation was one of the functional classes that is most frequently dysregulated in renal cell cancer. Mutation or mis-regulation of histone methylation, methyltransferases, demethylases are associated with gene expression and tumor progression in renal cell cancer. Herein, we summarize histone methylations, demethylases and their alterations and mechanisms in renal cell cancer.

The Role and Mechanism of Lysine Methyltransferase and Arginine Methyltransferase in Kidney Diseases

Methylation can occur in both histones and non-histones. Key lysine and arginine methyltransferases under investigation for renal disease treatment include enhancer of zeste homolog 2 (EZH2), G9a, disruptor of telomeric silencing 1-like protein (DOT1L), and protein arginine methyltransferases (PRMT) 1 and 5. Recent studies have shown that methyltransferases expression and activity are also increased in several animal models of kidney injury, such as acute kidney injury(AKI), obstructive nephropathy, diabetic nephropathy and lupus nephritis. The inhibition of most methyltransferases can attenuate kidney injury, while the role of methyltransferase in different animal models remains controversial. In this article, we summarize the role and mechanism of lysine methyltransferase and arginine methyltransferase in various kidney diseases and highlight methyltransferase as a potential therapeutic target for kidney diseases.

BIX01294 inhibits EGFR signaling in EGFR-mutant lung adenocarcinoma cells through a BCKDHA-mediated reduction in the EGFR level

BIX01294 (BIX), an inhibitor of the G9a histone methyltransferase, has been reported to have antitumor activity against a variety of cancers. However, the molecular mechanisms underlying its anticancer effects, particularly those against lung cancer, remain unclear. Here, we report that BIX induces apoptotic cell death in EGFR-mutant non-small cell lung cancer (NSCLC) cells but not in their wild-type counterparts. Treatment with BIX resulted in a significant reduction in the EGFR level and inhibition of EGFR signaling only in EGFR-mutant NSCLC cells, leading to apoptosis. BIX also inhibited mitochondrial metabolic function and decreased the cellular energy levels that are critical for maintaining the EGFR level. Furthermore, BIX transcriptionally downregulated the transcription of branched-chain α-keto acid dehydrogenase (BCKDHA), which is essential for fueling the tricarboxylic acid (TCA) cycle. Interestingly, this BCKDHA downregulation was due to inhibition of Jumanji-domain histone demethylases but not the G9a histone methyltransferase. We observed that KDM3A, a Jumonji histone demethylase, epigenetically regulates BCKDHA expression by binding to the BCKDHA gene promoter. BIX exposure also led to a significant decrease in the EGFR level, causing apoptosis in EGFR-TKI (tyrosine kinase inhibitor)-resistant cell lines, which are dependent on EGFR signaling for survival. Taken together, our current data suggest that BIX triggers apoptosis only in EGFR-mutant NSCLC cells via inhibition of BCKDHA-mediated mitochondrial metabolic function.

A drug known as BIX that is effective against bladder and breast cancers may also be effective in fighting non-small cell lung cancer (NSCLC). Although advances have been made in treatment of NSCLC, one of the most effective drugs targets a protein called EGFR, and EGFR gene mutations that lead to acquired drug resistance are common. Jaekyoung Son at the University of Ulsan, Seoul, South Korea, and colleagues investigated whether BIX is effective against NSCLC and attempted to elucidate its mechanism of action. The researchers found that BIX caused death of NSCLC cells, especially those with mutations in the EGFR gene. Further investigation showed that BIX was effective even against drug-resistant NSCLC cells, by acting via a different metabolic pathway. BIX shows promise as an alternative therapy for lung cancer, to overcome drug resistance.

BIX-01294, a G9a inhibitor, suppresses cell proliferation by inhibiting autophagic flux in nasopharyngeal carcinoma cells

G9a, a histone methyltransferase, has been found to be upregulated in a range of tumor tissues, and contributes to tumor growth and metastasis. However, the impact of G9a inhibition as a potential therapeutic target in nasopharyngeal carcinoma (NPC) is unclear. In the present study we aimed to investigate the anti-proliferative effect of G9a inhibition in the NPC cell lines CNE1 and CNE2, and to further elucidate the molecular mechanisms underlying these effects. The expression of G9a in NPC tumor tissues was significantly higher than that in normal nasopharyngeal tissues. The pharmacological inhibition of G9a by BIX-01294 (BIX) inhibited proliferation and induced caspase-independent apoptosis in NPC cells in vitro. Treatment with BIX induced autophagosome accumulation, which exacerbated the cytotoxic activity of BIX in NPC cells. Mechanistic studies have found that BIX impairs autophagosomes by initiating autophagy in a Beclin-1-independent way, and impairs autophagic degradation by inhibiting lysosomal cathepsin D activation, leading to lysosomal dysfunction. BIX was able to suppress tumor growth, possibly by inhibiting autophagic flux; it might therefore constitute a promising candidate for NPC therapy.

A Novel Nine Apoptosis-Related Genes Signature Predicting Overall Survival for Kidney Renal Clear Cell Carcinoma and its Associations with Immune Infiltration

Background: This study was designed to establish a sensitive prognostic model based on apoptosis-related genes to predict overall survival (OS) in patients with clear cell renal cell carcinoma (ccRCC). Methods: Obtaining the expression of apoptosis-related genes and associated clinical parameters from online datasets (The Cancer Genome Atlas, TCGA), their biological function analyses were performed through differently expressed genes. By means of LASSO, unadjusted and adjusted Cox regression analyses, this predictive signature was constructed and validated by internal and external databases (both TCGA and ArrayExpress). Results: A total of nine apoptosis-related genes (SLC27A2, TNFAIP2, IFI44, CSF2, IL4, MDK, DOCK8, WNT5A, APP) were ultimately screened as associated hub genes and utilized to construct a prognosis model. Then our constructed riskScore model significantly passed the validation in both the internal and external datasets of OS (all p < 0.05) and verified their expressions by qRT-PCR. Moreover, we conducted the Receiver Operating Characteristic (ROC), finding the area under the ROC curves (AUCs) were all above 0.70 which indicated that riskScore was a stable independent prognostic factor (p < 0.05). Furthermore, prognostic nomograms were established to figure out the relationship between 1-, 3- and 5-year OS and individual parameters for ccRCC patients. Additionally, survival analyses indicated that our riskScore worked well in predicting OS in subgroups of age, gender, grade, stage, T, M, N0, White (all p < 0.05), except for African, Asian and N1 (p > 0.05). We also explored its association with immune infiltration and applied cMap database to seek out highly correlated small molecule drugs. Conclusion: Our study successfully constructed a prognostic model containing nine hub apoptosis-related genes for ccRCC, helping clinicians predict patients' OS and making the prognostic assessment more standardized. Future prospective studies are required to validate our findings.

EHMT2 inhibitor BIX-01294 induces endoplasmic reticulum stress mediated apoptosis and autophagy in diffuse large B-cell lymphoma cells

Despite advancement in the treatment of diffuse large B-cell lymphoma (DLBCL), many patients tend to relapse or become refractory after initial therapy. Therefore, it is essential to identify novel therapeutic targets and drugs, understand the molecular pathogenesis mechanism of DLBCL, and find ways to prevent and treat relapsed or refractory DLBCL. BIX-01294 is a small molecule compound that specifically inhibits EHMT2 activity. In this study, we demonstrate that BIX-01294 triggered the inhibition of human DLBCL cell proliferation, lead to G₁ phase arrest via increasing P21 level and reducing cyclin E level. BIX-01294 also induced apoptosis via endogenous and exogenous apoptotic pathways. Moreover, BIX-01294 triggered autophagy and activated ER stress in human DLBCL cells. Furthermore, we showed that both key components of ER stress, ATF3, and ATF4, are required for BIX-01294-induced apoptosis and autophagy. Hence, this study provides new evidence that EHMT2 may be a new therapeutic target, and BIX-01294 may be a potential therapeutic drug for treating DLBCL.

BIX-01294-enhanced chemosensitivity in nasopharyngeal carcinoma depends on autophagy-induced pyroptosis

Nasopharyngeal carcinoma (NPC) is a common cancer in southern China and Southeast Asia. Nowadays, radiotherapy is the therapy of choice for NPC patients, and chemotherapy has been found as an alternative treatment for advanced NPC patients. However, finding novel drugs and pharmacologically therapeutic targets for NPC patients is still urgent and beneficial. Our study showed that BIX-01294 (BIX) can induce autophagic vacuoles formation and conversion of LC3B-I to LC3B-II in NPC cells in both dose- and time-dependent manners. Notably, the combination of BIX and chemotherapeutic drugs significantly decreased the cell viability and increased the lactate dehydrogenase release. Meanwhile, BIX plus cis-platinum (Cis) treatment induced pyroptosis in NPC cells as featured by cell swelling and bubble blowing from the plasma membrane, the increased frequency of annexin V and propidium iodide (PI) double-positive cells, as well as the cleavage of gasdermin E (GSDME) and caspase-3. Moreover, the deficiency of GSDME completely shifted pyroptosis to apoptosis. Furthermore, the inhibition of autophagy by chloroquine and the knockout of ATG5 gene significantly blocked the BIX-induced autophagy as well as pyroptosis in both in vitro and in vivo studies. Our data demonstrated that BIX-combined chemotherapeutic drugs could induce the Bax/caspase-3/GSDME-mediated pyroptosis through the activation of autophagy to enhance the chemosensitivity in NPC.

Improving TRAIL-induced apoptosis in cancers by interfering with histone modifications

Epigenetic regulation refers to alterations to the chromatin template that collectively establish differential patterns of gene transcription. Post-translational modifications of the histones play a key role in epigenetic regulation of gene transcription. In this review, we provide an overview of recent studies on the role of histone modifications in carcinogenesis. Since tumour-selective ligands such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) are well-considered as promising anti-tumour therapies, we summarise strategies for improving TRAIL sensitivity by inhibiting aberrant histone modifications in cancers. In this perspective we also discuss new epigenetic drug targets for enhancing TRAIL-mediated apoptosis.

Upregulation of DR5 and Downregulation of Survivin by IITZ-01, Lysosomotropic Autophagy Inhibitor, Potentiates TRAIL-Mediated Apoptosis in Renal Cancer Cells via Ubiquitin-Proteasome Pathway

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively is able to increase apoptosis in cancer cells as agent with minimum toxicity to noncancerous cells. However, all cancer cells are not sensitive to TRAIL-induced apoptosis. In this study, we showed the sub-lethal concentrations of a lysosomotropic autophagy inhibitor, IITZ-01, sensitizes cancer cells (renal, lung, and breast carcinoma) to TRAIL-induced apoptosis through DR5 upregulation and survivin downregulation through ubiquitin-proteasome pathway. Knockdown of DR5 or overexpression of survivin inhibited combined treatment with IITZ-01 and TRAIL-induced apoptosis. IITZ-01 downregulated protein expression of Cbl, ubiquitin E3 ligase, and decreased expression level of Cbl markedly led to increase DR5 protein expression and TRAIL sensitivity. Moreover, IITZ-01 decreased expression level of survivin protein via downregulation of deubiquitinase ubiquitin-specific protease 9X (USP9X) expression. Taken together, these results provide the first evidence that IITZ-01 enhances TRAIL-mediated apoptosis through DR5 stabilization by downregulation of Cbl and USP9X-dependent survivin ubiquitination and degradation in renal carcinoma cells.

TRAIL therapy and prospective developments for cancer treatment

Tumor Necrosis Factor (TNF) Related Apoptosis-Inducing Ligand (TRAIL), an immune cytokine of TNF-family, has received much attention in late 1990s as a potential cancer therapeutics due to its selective ability to induce apoptosis in cancer cells. TRAIL binds to cell surface death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5) and facilitates formation of death-inducing signaling complex (DISC), eventually activating the p53-independent apoptotic cascade. This unique mechanism makes the TRAIL a potential anticancer therapeutic especially for p53-mutated tumors. However, recombinant human TRAIL protein (rhTRAIL) and TRAIL-R agonist monoclonal antibodies (mAb) failed to exert robust anticancer activities due to inherent and/or acquired resistance, poor pharmacokinetics and weak potencies for apoptosis induction. To get TRAIL back on track as a cancer therapeutic, multiple strategies including protein modification, combinatorial approach and TRAIL gene therapy are being extensively explored. These strategies aim to enhance the half-life and bioavailability of TRAIL and synergize with TRAIL action ultimately sensitizing the resistant and non-responsive cells. We summarize emerging strategies for enhanced TRAIL therapy in this review and cover a wide range of recent technologies that will provide impetus to rejuvenate the TRAIL therapeutics in the clinical realm.

Novel cyclometalated iridium(iii) phosphine-imine (P^N) complexes: highly efficient anticancer and anti-lung metastasis agents in vivo

Iridium(iii)-based complexes with phosphine-imine (P^N) ligands are synthesized and authenticated. The combined treatment with Ir(iii) and BIX01294 potently inhibited tumour growth and lung metastasis in vitro and in vivo.

Honokiol Enhances TRAIL-Mediated Apoptosis through STAMBPL1-Induced Survivin and c-FLIP Degradation

Honokiol is a natural biphenolic compound extracted from traditional Chinese medicine Magnolia species, which have been known to display various biological effects including anti-cancer, anti-proliferative, anti-angiogenic, and anti-metastatic activities in cancer cells. Here, we found that honokiol sensitizes cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis through downregulation of anti-apoptotic proteins survivin and c-FLIP. Ectopic expression of survivin and c-FLIP markedly abolished honokiol and TRAIL-induced apoptosis. Mechanistically, honokiol induced protein degradation of c-FLIP and survivin through STAMBPL1, a deubiquitinase. STAMBPL1 interacted with survivin and c-FLIP, resulted in reduction of ubiquitination. Knockdown of STAMBPL1 reduced survivin and c-FLIP protein levels, while overexpression of STAMBPL1 inhibited honokinol-induced survivin and c-FLIP degradation. Our findings provided that honokiol could overcome TRAIL resistance through survivin and c-FLIP degradation induced by inhibition of STAMBPL1 expression.

Schistosoma japonicum Infection Promotes the Response of Tfh Cells Through Down-Regulation of Caspase-3-Mediating Apoptosis

CD4⁺ T follicular helper (Tfh) cells, a new subset of immune cells, have been demonstrated to be involved in granulomatous responses to Schistosoma japonicum (S. japonicum) infection. However, the role and underlying mechanisms of Tfh cell aggregation in S. japonicum infection remain incompletely understood. In this study, we provide evidence that S. japonicum infection enhances the accumulation of Tfh cells in the spleen, lymph nodes, and peripheral blood of C57BL/6 mice. Infection-induced Tfh cells exhibited more potent effects directly on B cell responses than the control Tfh cells (P < 0.05). Furthermore, reduced apoptosis of Tfh cells was found both in S. japonicum infected mice and in soluble egg antigen (SEA) treated Tfh cells (P < 0.05). Mechanistic studies reveal that caspase-3 is the primary drivers of down-regulated apoptotic Tfh cell death in S. japonicum infection. In summary, this study demonstrates that Tfh cell accumulation might have an impact on the generation of immune responses in S. japonicum infection, and caspase-3 signaling mediated apoptosis down-regulation might responsible for the accumulation of Tfh cell in this course.

WP1130 Enhances TRAIL-Induced Apoptosis through USP9X-Dependent miR-708-Mediated Downregulation of c-FLIP

WP1130, a partially selective deubiquitinases (DUB) inhibitor, inhibits the deubiquitinating activities of USP5, USP9X, USP14, USP37, and UCHL1. In this study, we investigate whether WP1130 exerts sensitizing effect on TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human renal carcinoma cells. Combinations of WP1130 and TRAIL significantly induced apoptosis in renal carcinoma, lung carcinoma and hepatocellular carcinoma cells, but not in normal cells (human mesangial cells (MC) and normal mouse kidney cells (TCMK-1)). The downregulation of c-FLIP protein expression was involved in combined treatment-induced apoptosis. WP1130-induced c-FLIP downregulation was regulated by microRNA (miR)-708 upregulation via inhibition of USP9X. Interestingly, knockdown of USP9X markedly induced c-FLIP downregulation, upregulation of miR-708 expression and sensitivity to TRAIL. Furthermore, ectopic expression of USP9X prevented c-FLIP downregulation and apoptosis upon combined treatment. In sum, WP1130 sensitized TRAIL-induced apoptosis through miR-708-mediated downregulation of c-FLIP by inhibition of USP9X.