Knockdown Of Bcl-2 Research Articles

Bcl-2 knockdown by multifunctional lipid nanoparticle and its influence in apoptosis pathway regarding cutaneous melanoma: in vitro and ex vivo studies.

Multifunctional therapies have emerged as innovative strategies in cancer treatment. In this research article, we proposed a nanostructured lipid carrier (NLC) designed for the topical treatment of cutaneous melanoma, which simultaneously delivers 5-FU and Bcl-2 siRNA. The characterized nanoparticles exhibited a diameter of 259 ± 9nm and a polydispersion index of 0.2, indicating a uniform size distribution. The NLCs were primarily localized in the epidermis, effectively minimizing the systemic release of 5-FU across skin layers. The ex vivo skin model revealed the formation of a protective lipid film, decreasing the desquamation process of the stratum corneum which can be associated to an effect of increasing permeation. In vitro assays demonstrated that A375 melanoma cells exhibited a higher sensitivity to the treatment compared to non-cancerous cells, reflecting the expected difference in their metabolic rates. The uptake of NLC by A375 cells reached approximately 90% within 4h. The efficacy of Bcl-2 knockdown was thoroughly assessed using ELISA, Western blot, and qRT-PCR analyses, revealing a significant knockdown and synergistic action of the NLC formulation containing 5-FU and Bcl-2 siRNA (at low concentration --100 pM). Notably, the silencing of Bcl-2 mRNA also impacted other members of the Bcl-2 protein family, including Mcl-1, Bcl-xl, BAX, and BAK. The observed modulation of these proteins strongly indicated the activation of the apoptosis pathway, suggesting a successful inhibition of melanoma growth and prevention of its in vitro spread.

Bcl-2 dependent modulation of Hippo pathway in cancer cells

IntroductionBcl-2 and Bcl-xL are the most studied anti-apoptotic members of Bcl-2 family proteins. We previously characterized both of them, not only for their role in regulating apoptosis and resistance to therapy in cancer cells, but also for their non-canonical functions, mainly including promotion of cancer progression, metastatization, angiogenesis, and involvement in the crosstalk among cancer cells and components of the tumor microenvironment. Our goal was to identify transcriptional signature and novel cellular pathways specifically modulated by Bcl-2.MethodsWe performed RNAseq analysis of siRNA-mediated transient knockdown of Bcl-2 or Bcl-xL in human melanoma cells and gene ontology analysis to identify a specific Bcl-2 transcriptional signature. Expression of genes modulated by Bcl-2 and associated to Hippo pathway were validated in human melanoma, breast adenocarcinoma and non-small cell lung cancer cell lines by qRT-PCR. Western blotting analysis were performed to analyse protein expression of upstream regulators of YAP and in relation to different level of Bcl-2 protein. The effects of YAP silencing in Bcl-2 overexpressing cancer cells were evaluated in migration and cell viability assays in relation to different stiffness conditions. In vitro wound healing assays and co-cultures were used to evaluate cancer-specific Bcl-2 ability to activate fibroblasts.ResultsWe demonstrated the Bcl-2-dependent modulation of Hippo Pathway in cancer cell lines from different tumor types by acting on upstream YAP regulators. YAP inhibition abolished the ability of Bcl-2 to increase tumor cell migration and proliferation on high stiffness condition of culture, to stimulate in vitro fibroblasts migration and to induce fibroblasts activation.ConclusionsWe discovered that Bcl-2 regulates the Hippo pathway in different tumor types, promoting cell migration, adaptation to higher stiffness culture condition and fibroblast activation. Our data indicate that Bcl-2 inhibitors should be further investigated to counteract cancer-promoting mechanisms.

HIF-1 contributes to autophagy activation via BNIP3 to facilitate renal fibrosis in hypoxia in vitro and UUO in vivo.

The molecular basis of renal interstitial fibrosis, a major pathological feature of progressive kidney diseases, remains poorly understood. Autophagy has been implicated in renal fibrosis, but whether it promotes or inhibits fibrosis remains controversial. Moreover, it is unclear how autophagy is activated and sustained in renal fibrosis. The present study was designed to address these questions using the in vivo mouse model of unilateral ureteral obstruction and the in vitro model of hypoxia in renal tubular cells. Both models showed the activation of hypoxia-inducible factor-1 (HIF-1) and autophagy along with fibrotic changes. Inhibition of autophagy with chloroquine reduced renal fibrosis in unilateral ureteral obstruction model, whereas chloroquine and autophagy-related gene 7 knockdown decreased fibrotic changes in cultured renal proximal tubular cells, supporting a profibrotic role of autophagy. Notably, pharmacological and genetic inhibition of HIF-1 led to the suppression of autophagy and renal fibrosis in these models. Mechanistically, knock down of BCL2 and adenovirus E1B 19-kDa-interacting protein 3 (BNIP3), a downstream target gene of HIF, decreased autophagy and fibrotic changes during hypoxia in BUMPT cells. Together, these results suggest that HIF-1 may activate autophagy via BNIP3 in renal tubular cells to facilitate the development of renal interstitial fibrosis.NEW & NOTEWORTHY Autophagy has been reported to participate in renal fibrosis, but its role and underlying activation mechanism is unclear. In this study, we report the role of HIF-1 in autophagy activation in models of renal fibrosis and further investigate the underlying mechanism.

The mitochondrial genome-encoded peptide MOTS-c interacts with Bcl-2 to alleviate nonalcoholic steatohepatitis progression

Nonalcoholic steatohepatitis (NASH) is a metabolism-associated fatty liver disease with accumulated mitochondrial stress, and targeting mitochondrial function is a potential therapy. The mitochondrial genome-encoded bioactive peptide MOTS-c plays broad physiological roles, but its effectiveness and direct targets in NASH treatment are still unclear. Here, we show that long-term preventive and short-term therapeutic effects of MOTS-c treatments alleviate NASH-diet-induced liver steatosis, cellular apoptosis, inflammation, and fibrosis. Mitochondrial oxidative capacity and metabolites profiling analysis show that MOTS-c significantly reverses NASH-induced mitochondrial metabolic deficiency. Moreover, we identify that MOTS-c directly interacts with the BH3 domain of antiapoptotic B cell lymphoma-2 (Bcl-2), increases Bcl-2 protein stability, and suppresses Bcl-2 ubiquitination. By using a Bcl-2 inhibitor or adeno-associated virus (AAV)-mediated Bcl-2 knockdown, we further confirm that MOTS-c improves NASH-induced mitochondrial dysfunction, inflammation, and fibrosis, which are dependent on Bcl-2 function. Therefore, our findings show that MOTS-c is a potential therapeutic agent to inhibit the progression of NASH.

Doxorubicin-conjugated siRNA lipid nanoparticles for combination cancer therapy.

Evasion of apoptosis is a hallmark of cancer, attributed in part to overexpression of the anti-apoptotic protein B-cell lymphoma 2 (Bcl-2). In a variety of cancer types, including lymphoma, Bcl-2 is overexpressed. Therapeutic targeting of Bcl-2 has demonstrated efficacy in the clinic and is the subject of extensive clinical testing in combination with chemotherapy. Therefore, the development of co-delivery systems for Bcl-2 targeting agents, such as small interfering RNA (siRNA), and chemotherapeutics, such as doxorubicin (DOX), holds promise for enabling combination cancer therapies. Lipid nanoparticles (LNPs) are a clinically advanced nucleic acid delivery system with a compact structure suitable for siRNA encapsulation and delivery. Inspired by ongoing clinical trials of albumin-hitchhiking doxorubicin prodrugs, here we developed a DOX-siRNA co-delivery strategy via conjugation of doxorubicin to the surface of siRNA-loaded LNPs. Our optimized LNPs enabled potent knockdown of Bcl-2 and efficient delivery of DOX into the nucleus of Burkitts' lymphoma (Raji) cells, leading to effective inhibition of tumor growth in a mouse model of lymphoma. Based on these results, our LNPs may provide a platform for the co-delivery of various nucleic acids and DOX for the development of new combination cancer therapies.

IL-17A inhibits the degradation of RANKL in osteoblasts by inhibiting BCL2-Beclin1-autophagy signaling

The inflammatory cytokine IL-17A is known to have the capacity to promote osteoclastogenesis, thereby enhancing bone loss. Moreover, IL-17A can promote the expression of RANKL in osteoblasts, contributing to its pro-osteoclastogenic effect. IL-17A is an autophagy regulator, which is also responsible for its regulation on RANKL expression. However, the specific role of autophagy in IL-17A-regulated RANKL expression and the underlying mechanism of IL-17A-regulated osteoblast autophagy remain unclear. IL-17A is known to inhibit autophagy by preventing BCL2 degradation. This study aimed to explore the significance of BCL2-dependent autophagy in IL-17A-regulated RANKL expression. Our results showed that IL-17A at 50 ng/mL could inhibit autophagic activity and promote RANKL protein expression in MC3T3-E1 osteoblast line. Moreover, the corresponding concentration of IL-17A could enhance BCL2 protein expression and the protein interaction between BCL2 and Beclin1 in MC3T3-E1 cells. However, the protein expression of RANKL and BCL2 promoted by 50 ng/mL of IL-17A was blocked by autophagy activation with Beclin1 pharmacological upregulation. Furthermore, RANKL protein expression promoted by 50 ng/mL of IL-17A was also reversed by autophagy activation with BCL2 knockdown. Importantly, the supernatant from osteoblasts treated with 50 ng/mL of IL-17A made osteoclast precursors (OCPs) form larger osteoclasts, which was reversed by BCL2 knockdown in osteoblasts. In conclusion, high levels of IL-17A prevent the degradation of RANKL by inhibiting BCL2-Beclin1-autophagy activation signal transduction in osteoblasts, thereby indirectly promoting osteoclastogenesis.

Synergistic Interactions between the Hypomethylating Agent Thio-Deoxycytidine and Venetoclax in Myelodysplastic Syndrome Cells

Interactions between the novel hypomethylating agent (HMA) thio-deoxycytidine (T-dCyd) and the BCL-2 antagonist ABT-199 (venetoclax) have been examined in human myelodysplastic syndrome (MDS) cells. The cells were exposed to agents alone or in combination, after which apoptosis was assessed, and a Western blot analysis was performed. Co-administration of T-dCyd and ABT-199 was associated with the down-regulation of DNA methyltransferase 1 (DNMT1) and synergistic interactions documented by a Median Dose Effect analysis in multiple MDS-derived lines (e.g., MOLM-13, SKM-1, and F-36P). Inducible BCL-2 knock-down significantly increased T-dCyd's lethality in MOLM-13 cells. Similar interactions were observed in the primary MDS cells, but not in the normal cord blood CD34+ cells. Enhanced killing by the T-dCyd/ABT-199 regimen was associated with increased reactive oxygen species (ROS) generation and the down-regulation of the anti-oxidant proteins Nrf2 and HO-1, as well as BCL-2. Moreover, ROS scavengers (e.g., NAC) reduced lethality. Collectively, these data suggest that combining T-dCyd with ABT-199 kills MDS cells through an ROS-dependent mechanism, and we argue that this strategy warrants consideration in MDS therapy.

Circ-JA760602 promotes the apoptosis of hypoxia-induced cardiomyocytes by transcriptionally suppressing BCL2.

Acute myocardial infarction (AMI) is myocardial necrosis caused by the complete or partial obstruction of a coronary artery. Circular RNAs (circRNAs) have been proven as regulators in the progression of various human diseases, including AMI. However, the role of novel circ-JA760602 in AMI remains unknown. Here, we investigated the role of circ-JA760602 in modulating the apoptosis of hypoxia-induced AMI cells using the AC16 cardiomyocyte in vitro cell model. The expression of circ-JA760602 in AC16 cardiomyocytes subjected to hypoxia was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was measured by cell counting kit-8 (CCK-8) assay. Apoptosis of cardiomyocytes was evaluated by TUNEL assay and flow cytometry analysis. The cellular location of circ-JA760602 was identified through fluorescence in situ hybridization (FISH) assay and subcellular fractionation assay. The downstream molecular mechanisms of circ-JA760602 were demonstrated by luciferase reporter assay, RNA binding protein immunoprecipitation (RIP) assay and chromatin immunoprecipitation (ChIP) assay. Rescue assays were performed to demonstrate the effects of BCL2 knockdown on circ-JA760602 silencing-mediated cardiomyocyte apoptosis. Circ-JA760602 expression was elevated after hypoxia treatment. Knockdown of circ-JA760602 enhanced viability and curbed apoptosis of hypoxia-treated cardiomyocytes. EGR1 and E2F1 could activate BCL2 transcription. Cytoplasmic circ-JA760602 bound with EGR1 and E2F1 to thus inhibit their nuclear translocation. BCL2 knockdown reversed the effects of circ-JA760602 silencing on the apoptosis of hypoxia-treated AC16 cells. Circ-JA760602 promotes hypoxia-induced apoptosis of cardiomyocytes by binding with EGR1 and E2F1 to inhibit the transcriptional activation of BCL2.

Selective Vulnerability of Senescent Glioblastoma Cells to BCL-XL Inhibition.

Glioblastoma (GBM) is a rapidly fatal malignancy typically treated with radiation and temozolomide (TMZ), an alkylating chemotherapeutic. These cytotoxic therapies cause oxidative stress and DNA damage, yielding a senescent-like state of replicative arrest in surviving tumor cells. Unfortunately, recurrence is inevitable and may be driven by surviving tumor cells eventually escaping senescence. A growing number of so-called “senolytic” drugs have been recently identified that are defined by their ability to selectively eliminate senescent cells. A growing inventory of senolytic drugs is under consideration for several diseases associated with aging, inflammation, DNA damage, as well as cancer. Ablation of senescent tumor cells after radiation and chemotherapy could help mitigate recurrence by decreasing the burden of residual tumor cells at risk of recurrence. This strategy has not been previously explored for GBM. We evaluated a panel of 10 previously described senolytic drugs to determine whether any could exhibit selective activity against human GBM persisting after exposure to radiation or TMZ. Three of the 10 drugs have known activity against BCL-XL and preferentially induced apoptosis in radiated or TMZ-treated glioma. This senolytic activity was observed in 12 of 12 human GBM cell lines. Efficacy could not be replicated with BCL-2 inhibition or senolytic agents acting against other putative senolytic targets. Knockdown of BCL-XL decreased survival of radiated GBM cells, whereas knockdown of BCL-2 or BCL-W yielded no senolytic effect.

Upregulation of microRNA-34a enhances myocardial ischemia-reperfusion injury via the mitochondrial apoptotic pathway

Mitochondrial oxidative injury can result in many cardiovascular diseases including cardiac ischemia-reperfusion (I/R) injury. This study was designed to investigate whether microRNA-34a (miR-34a) influences cardiac I/R or hypoxia/reoxygenation (H/R) injury by regulating the mitochondrial apoptotic pathway from oxidative injury.In vivo, myocardial infarction size was examined by Evan blue/TTC staining. Apoptosis was assessed by TUNEL assay. Heart function was measured by echocardiography. Lactate dehydrogenase (LDH) and creatine kinase (CK) were evaluated. In vitro, H9c2 cardiomyocytes were exposed to H/R stimulation. Cell viability was assessed by the CCK-8 assay and apoptosis was detected by Annexin V/PI staining. Mitochondrial superoxide, mitochondrial membrane potential (MMP) and ATP production was evaluated by detection kits, and related proteins were detected by western blotting analysis. We observed that the level of miR-34a was significantly upregulated in I/R rats compared to the sham group. Injection of adenovirus inhibiting miR-34a into the left ventricular anterior wall improved heart function and decreased I/R injury. H9c2 cardiomyocytes exposed to H/R stimulation displayed an obvious increase in miR-34a expression. In addition, miR-34a inhibitor alleviated, whereas miR-34a mimic aggravated H/R-induced mitochondrial injury. Bcl-2 was identified as a target gene of miR-34a by dual-luciferase reporter gene detection. Knockdown of Bcl-2 abolished the cardioprotection of the miR-34a inhibitor in H9c2 cells. In summary,our study demonstrates that inhibition of miR-34a exhibits therapeutic potential in treatment of myocardial I/R injury by restraining mitochondrial apoptosis.

Abstract P079: The impact of BCL2 expression on sensitivity to the novel Aurora kinase B inhibitor AZD2811 in small cell lung cancer

Abstract Purpose: Small cell lung cancer (SCLC) is a highly lethal malignancy, with rapidly-acquired therapeutic resistance. In contrast to non-SCLC, treatment strategies based on molecular subtypes have not been well established. Aurora kinase family proteins (AURKA and AURKB) are essential for cell division, regulating chromosomal segregation during mitosis, and are upregulated in cancer. Our group has demonstrated that cMYC-driven SCLC tumors were susceptible to an AURKA inhibitor, alisertib, making AURK proteins an attractive targeted therapeutic approach. A novel AURKB inhibitor, AZD2811NP (nanoparticle), is now being investigated in relapsed SCLC patients (NCT02579226), but molecular mechanisms of resistance have not yet been identified. Here, we hypothesize that targeting predictive markers related to the effect of AZD2811 may reinforce susceptibility to AURKB inhibition. Experimental Design: We evaluated susceptibility to AZD2811 in 63 human-derived SCLC cell lines using 96-hour proliferation assays. To identify translatable biomarkers of response, we correlated AZD2811 IC50 values with genomic (whole exome sequencing, WES), transcriptomic (RNASeq), and proteomic profiling (Reverse Phase Protein Array, RPPA) data. We validated changes in apoptosis and DNA damage markers induced by AZD2811 in SCLC cells infected with the lentivirus vectors expressing BCL-2 and shRNA against BCL-2 using western blot. We used SCLC patient-derived xenograft (PDX) models with distinct BCL-2 profiles to evaluate in vivo antitumor effect. Results: In the SCLC cells treated with AZD2811, 15/63 (24%) and 10/63 (16%) cell lines showed high sensitivity (IC50<30 nM, Cmax) and intermediate sensitivity (IC50=30-100nM). Comparing protein expression, we found that cMYC (Fold change, FC:2.5; P = 0.015) were a positive biomarker of sensitivity, while high BCL-2 (FC:1.86; P = 0.032) associated with resistance. cMYC-high SCLC cell lines that were susceptible to AZD2811 became resistant when BCL-2 was overexpressed. Conversely, BCL-2 knock-down enhanced response to AZD2811, inducing apoptosis and DNA damage, in BCL-2-high cells that were originally resistant to single-agent AZD2811. Similar to Bcl-2 knock-down, treatment with venetoclax (a BCL-2 inhibitor routinely used in other cancers) enhanced apoptosis and DNA damage induction in combination with AZD2811 in cells overexpressing BCL-2. In PDX models with high BCL-2, combination of AZD2811 and venetoclax prominently induced tumor regression and apoptosis compared with each monotherapy, while there was no significant difference in PDX models with low BCL-2 between the combination and the monotherapy. Conclusions: Our preclinical results indicate that high BCL-2 expression reduced the efficacy of AZD2811 in SCLC models, but that Bcl2-driven resistance could be overcome with the combined use of BCL-2 and AURKB inhibitors. Findings support a promising rational combination therapy for BCL-2-high SCLC to enhance response to aurora kinase B inhibition. Citation Format: Azusa Tanimoto, Carminia M. Della Corte, Kavya Ramkumar, Robert J. Cardnell, Allison C. Stewart, Carl M. Gay, Lauren Averett Byers, Qi Wang, Li Shen, Jing Wang, Jon Travers. The impact of BCL2 expression on sensitivity to the novel Aurora kinase B inhibitor AZD2811 in small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P079.

Wogonin protects glomerular podocytes by targeting Bcl-2-mediated autophagy and apoptosis in diabetic kidney disease

Diabetic kidney disease (DKD) is one of the microvascular complications of diabetes mellitus and a major cause of end-stage renal disease with limited treatment options. Wogonin is a flavonoid derived from the root of Scutellaria baicalensis Georgi, which has shown a potent renoprotective effect. But the mechanisms of action in DKD are not fully elucidated. In this study, we investigated the effects of wogonin on glomerular podocytes in DKD using mouse podocyte clone 5 (MPC5) cells and diabetic mice model. MPC5 cells were treated with high glucose (30 mM). We showed that wogonin (4, 8, 16 μM) dose-dependently alleviated high glucose (HG)-induced MPC5 cell damage, accompanied by increased expression of WT-1, nephrin, and podocin proteins, and decreased expression of TNF-α, MCP-1, IL-1β as well as phosphorylated p65. Furthermore, wogonin treatment significantly inhibited HG-induced apoptosis in MPC5 cells. Wogonin reversed HG-suppressed autophagy in MPC5 cells, evidenced by increased ATG7, LC3-II, and Beclin-1 protein, and decreased p62 protein. We demonstrated that wogonin directly bound to Bcl-2 in MPC5 cells. In HG-treated MPC5 cells, knockdown of Bcl-2 abolished the beneficial effects of wogonin, whereas overexpression of Bcl-2 mimicked the protective effects of wogonin. Interestingly, we found that the expression of Bcl-2 was significantly decreased in biopsy renal tissue of diabetic nephropathy patients. In vivo experiments were conducted in STZ-induced diabetic mice, which were administered wogonin (10, 20, 40 mg · kg−1 · d−1, i.g.) every other day for 12 weeks. We showed that wogonin administration significantly alleviated albuminuria, histopathological lesions, and p65 NF-κB-mediated renal inflammatory response. Wogonin administration dose-dependently inhibited podocyte apoptosis and promoted podocyte autophagy in STZ-induced diabetic mice. This study for the first time demonstrates a novel action of wogonin in mitigating glomerulopathy and podocytes injury by regulating Bcl-2-mediated crosstalk between autophagy and apoptosis. Wogonin may be a potential therapeutic drug against DKD.

Abstract 988: Targeting immunological and apoptotic cell death to improve therapeutic efficacy in melanoma

Abstract Apoptotic and immunological cell death are the two major pathways that can lead to demise of cancer cells. Targeting both pathways by combining chemotherapy and checkpoint inhibitors has proven to be more effective in treating lung cancer but not in melanoma, due to the fact that melanoma cells often express high levels of antiapoptotic proteins Bcl-2 ( 60%) which contribute to their resistance to chemotherapy. We have previously shown that melanoma cell lines with high Bcl-2 expression , regardless of their BRAF mutation, do not possess high PD-L1 ( AACR abstract #4747 2019). This is also seen in melanoma tissue obtained from patients. Here, we attempt to explore whether there is any relationship between Bcl-2 and PD-L1 in melanoma cells using knock in and knock out methods. Two melanoma cells derived from patients ( mel1220 which possess high levels of Bcl-2 and Mel-F which possess high levels of PD-L1 ) and their BRAF/MEK counterparts, Mel-1220 BMR and MelF BMR, respectively, were used for the study. Interestingly, cell lines with high Bcl-2 , their BMR counterparts showed no changes in Bcl-2 levels, However, in cell lines with high PD-L1 expression, the levels of PD-L1 is even higher when they become BMR. This could explain why after failure to BRAF/MEK inhibitor , the clinical response to anti PD-1 check point inhibitors varies. Next, we transfected PD-L1 using the SP-GFP-CD274-NU Vector ( purchased from Addgene )into the BcL-2 over expressing cell lines. Three clones were selected. Two clones ( 1220.PD-L1/1 and 1220 PD-L1/3) showed only slight decreased Bcl-2 expression ( less than 1 fold) and in one clone ( 1220.PD-L1/2), there is no effect seen. Furthermore, there is no discernable change in other antiapoptotic proteins ( Bcl-xl, BAX, Mcl-2 survivin, NOXA and PUMA ) by westernblot noted. Similar results were obtained with their BMR counterparts. Total knock down of Bcl-2 using CRISPR knockout ( kit purchased from Origene) results in cell death. In contrast, transfection of Bcl2 into PD-L1 overexpression results in decreased PD-L1 expression by 2-4 fold both by PCR and by westernblot in both clones. however , there is no discernable changes on surface PD-L1 by flow cytometery. Transfection of BCl-2 also does not affect other BCL-2 family proteins. Similar results were obtained with their BMR counterparts. From these data, it appears that the presence of Bcl-2 ( RNA/protein) could affect intrinsic PD-L1 expression, however, the surface PD-L1 which is the key to bind PD-1 did not change. On the other hand, the presence of PD-L1 RNA/protein has no discernable effect on BcL-2 expression. Whether partial knock down BCl-2 or treatment with Bcl-2 inhibitor can lead to increased PD-L1 expression is not known and is under investigation. Overall, it appears that combination of Bcl-2 inhibitor and check point inhibitor may be more effective in melanoma patients with high Bcl-2 expression. (Supported by VA merit review award; 1BX003328) Citation Format: Niramol Savaraj, Min You, Ying-Ying Li, Chunjing Wu, Medhi Wangpaichitr, Saurez Miguel, Alfred Chicco, Macus T. Kuo, Lynn G. Feun. Targeting immunological and apoptotic cell death to improve therapeutic efficacy in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 988.

MiRNA-Mediated Knock-Down of Bcl-2 and Mcl-1 Increases Fludarabine-Sensitivity in CLL-CII Cells.

Background:Over-expression of anti-apoptotic proteins such as Bcl-2 and Mcl-1 is associated with resistance to chemotherapeutic agents such as fludarabine. Moreover, an inverse relationship between miRNA-15a levels with Bcl-2 and Mcl-1 expression has been observed in CLL patients. In this study, the effect of miRNA-15a on apoptosis and sensitivity of the CLL cells to fludarabine was investigated. Methods:After treatments, the Mcl-1 and Bcl-2 expression levels were quantified by RT-qPCR. Trypan blue assay was used to explore the effects of miRNA-15a and fludarabine on cell proliferation. The cytotoxicity was measured using MTT assay and combination index analysis. Cell death was determined using cell death detection ELISA assay and caspase-3 activity assay Kits. Results:Results showed that miRNA-15a clearly decreased the mRNA levels of Bcl-2 and Mcl-1 in a time dependent manner, which led to CLL-II cell proliferation inhibition and enhancement of apoptosis (p < 0.05, relative to control). Transfection of the miRNA-15a synergistically reduced the cell survival rate and lowered the IC50 value of fludarabine. Furthermore, miRNA-15a significantly enhanced the apoptotic effect of fludarabine. Conclusions:Our data propose that suppression of Bcl-2 and Mcl-1 by miRNA-15a can effectively inhibit the cell proliferation and sensitize CLL cells to fludarabine. Therefore, miRNA-15a can be considered as a potential therapeutic target in CLL resistant patients.

Study on effects of miR-141-3p in proliferation, migration, invasion and apoptosis of colon cancer cells by inhibiting Bcl2.

This study aimed to investigate the relationship between miR-141-3p and B lymphocyte-2 gene (Bcl2) gene and its biological behavior on colon cancer cell line SW480. qRT-PCR was used to detect the expression level of miR-141-3p in colon cancer tissues and adjacent tissues, as well as in colon cancer cell line and normal human colonic epithelial cell line FHC. MTT assay, wound assay, and Transwell demonstrated the effects of miR-141-3p on colon cancer proliferation, migration and invasion. Targetscan7.1 predictive software and dual luciferase reporter assays were used to detect the targeted regulation of miR-141-3p on the apoptosis-related gene Bcl2. MTT assay, wound assay, Transwell and flow cytometry were used to detect the effect of Bcl2 on miR-141-3p on colon cancer proliferation, migration, invasion and apoptosis. Compared with adjacent tissues, the expression of miR-141-3p in colon cancer tissues was significantly down-regulated. Colon cancer patients with low expression of miR-141-3p had poorer prognosis. Compared with normal colonic epithelial cells, miR-141-3p expression was significantly down-regulated in colon cancer cell lines, and overexpression of miR-141-3p significantly attenuated the proliferation, migration and invasion of colon cancer cells. Knockdown of miR-141-3p significantly promoted the proliferation, migration and invasion of colon cancer cells. miR-141-3p targets the negative regulation of Bcl2. Knockdown of Bcl2 significantly attenuated the promotion of miR-141-3p inhibitor on proliferation, migration and invasion of colon cancer cells and inhibition of apoptosis. Knockdown of Bcl2 significantly enhanced the inhibition effect of miR-141-3p inhibitor on proliferation, migration and invasion of colon cancer cells. In conclusion, miR-141-3p can inhibit the cancer by regulating Bcl2, and miR-141-3p has the potential to become a potential therapeutic target for colon cancer.

MiR‐140‐3p inhibits colorectal cancer progression and its liver metastasis by targeting BCL9 and BCL2

Recent studies have identified microRNAs (miRNAs) as a compelling novel class of biomarker in colorectal cancer (CRC) development and metastasis. Here, we demonstrated that the level of plasma exosomal miR‐140‐3p in CRC patients was lower than that in healthy controls. The decreased miR‐140‐3p level was also observed in CRC patients with liver metastasis. The expression of miR‐140‐3p in CRC tissues were significantly lower than that in matched normal tissues. Functionally, miR‐140‐3p overexpression suppressed proliferation, migration, invasion, and β‐catenin nuclear translocation, as well as promoted apoptosis in LoVo cells, while inhibition of miR‐140‐3p reversed these cellular processes in HCT 116 cells. Notably, BCL9 and BCL2 were recognized as direct targets of miR‐140‐3p. BCL9 knockdown abrogated miR‐140‐3p inhibitor‐induced effects on HCT 116 cells with decreased proliferation, migration, and invasion. BCL2 knockdown increased apoptosis of miR‐140‐3p inhibitor‐transfected HCT 116 cells. In vivo experiments revealed that miR‐140‐3p overexpression inhibited tumor growth in LoVo xenograft model and diminished metastatic nodules in nude mice liver. Taken together, this work supports that miR‐140‐3p exerts as a tumor suppressor in CRC progression via targeting BCL9 and BCL2, and suggests miR‐140‐3p‐BCL9/BCL2 axis may be applied in miRNA‐based therapy and prognostication of CRC.

MiR-30c-5p inhibits glioma proliferation and invasion via targeting Bcl2.

BackgroundGlioma is a highly malignant brain tumor, characterized by the poor prognosis and high recurrence rates. Previous studies have confirmed that miRNA-30c-5p is closely associated with tumor cell biological properties. The present study explored the biological role of miR-30c-5p in human glioma malignant behavior and underlying mechanisms.MethodsLevels of miR-30c-5p were detected in glioma tissues and adjacent normal tissues. Two glioma cell lines including U87 and U251 were transfected with miR-30c-5p mimic or inhibitors. Cell proliferation was evaluated by MTT assay and colony formation assay. Cell apoptosis and invasive potential of glioma cells were assessed by flow cytometry and transwell assays, respectively. Luciferase reporter assay was performed to validate the target gene of miR-30c-5p.ResultsLevels of miR-30c-5p were dramatically decreased in glioma tissues as compared to the adjacent normal tissues. Upregulation of miR-30c-5p significantly suppressed cell growth and colony formation, and induced apoptosis in glioma cells. In contrast, inhibition of miR-30c-5p promoted the proliferation and inhibited apoptosis in tumor cells. Furthermore, miR-30c-5p strongly suppresses the invasion of glioma cells. Western blot showed that Bcl-2 was significantly decreased following treatment with miR-30c-5p mimics and increased after miR-30c-5p inhibitor treatment. Moreover, luciferase reporter assays indicated that transfection of miR-30c-5p led to a marked reduction of luciferase activity, but had no effect on Bcl-2 3'-UTR mutated fragment. Mechanically, miR-30c-5p promoted the activation of caspase 3 and caspase 9 in glioma cells. Furthermore, miR-30c-5p promoted apoptosis and inhibited colony formation and migration, and knockdown of Bcl2 further increased the number of apoptotic cells and suppressed colony formation and migration of glioma cells. By contrast, miR-30c-5p inhibitors decreased apoptosis and increased colony formation and migration, and restored Bcl2 expression further suppressed glioma cell apoptosis and enhanced colony formation and migration.ConclusionsThese results demonstrated that miR-30c-5p regulated growth, apoptosis and migration in glioma cells by targeting Bcl2, suggesting that miR-30c-5p might serve as a novel target for glioma therapy.

Insight into the Protective Effect of Salidroside against H2O2-Induced Injury in H9C2 Cells.

Salidroside is the important active ingredient of Rhodiola species, which shows a wide range of pharmacological activities such as antioxidative stress, anti-inflammation, and antiliver fibrosis. In this paper, we aimed to study the protective effect and mechanism of salidroside against H2O2-induced oxidative damage in H9C2 cells by determining cell proliferation rate, intracellular reactive oxygen species (ROS) level, antioxidant enzyme activities, and the expression of apoptosis-related proteins. The results showed that salidroside significantly alleviated cell growth inhibition induced by H2O2 treatment in H9C2 cells, decreased the levels of intracellular ROS and malondialdehyde (MDA), and increased the activity of superoxide dismutase (SOD) and catalase (CAT); meanwhile, salidroside upregulated the expression of Bcl-2 while downregulated the expression of Bax, p53, and caspase-3 in H2O2-treated H9C2 cells. Furthermore, the antiapoptotic effect of salidroside was almost eliminated by the knockdown of Bcl-2. In the further exploration, the Bcl-2 expression was decreased by the p53 overexpression and increased by p53 knockdown in H2O2-treated H9C2 cells. Consequently, salidroside could protect H9C2 cells against H2O2-induced oxidative damage, and the underlying mechanism may be related to scavenging intracellular ROS, increasing the activities of intracellular antioxidant enzymes and inhibiting the expression of apoptosis-related proteins.

Long noncoding RNA CEBPA-DT promotes cisplatin chemo-resistance through CEBPA/BCL2 mediated apoptosis in oral squamous cellular cancer.

Intrinsic or developing resistance to chemotherapy drugs including cisplatin (CDDP) remains the major limitation of cancer therapeutic efficacy in cancers. Recently, increasing evidence suggested that long noncoding RNAs (lncRNAs) play a critical role in various biological processes of tumors, and have been implicated in resistance to various drugs. However, the role of lncRNAs in cisplatin resistance is poorly understood. Here, we found that the expression of lncRNA CEBPA-DT/CEBPA/BCL2 was upregulated in cisplatin resistance OSCC cells (Cal27-CisR and HSC4-CisR) compared with their parental cells (Cal27 and HSC4). CEBPA-DT overexpression could upregulated both cytoplasmic and nuclear CEBPA expression. Down-regulation of CEBPA-DT enhances cisplatin sensitivity, facilitates cell apoptosis in cisplatin-resistant OSCC cells. In addition, we identified that CEBPA-DT regulates cisplatin chemosensitivity through CEBPA/BCL2-mediated cell apoptosis. Knockdown of CEBPA and BCL2 could alleviate the increasement of cisplatin resistance induced by CEBPA-DT overexpression. Our findings indicate that downregulation of lncRNA CEBPA-DT may be a potential therapy to overcome cisplatin resistance in OSCC.

Autophagy promotes malignant migration and invasion via miR-224-5p/BCL2 in pancreatic mucinous cystadenocarcinoma MCC1 cells.

The prognosis of invasive pancreatic mucinous cystadenocarcinoma (MCC) is poor, and the molecular mechanism underlying its development remains unclear. The present study aimed to explore the potential role of autophagy in pancreatic MCC. The results demonstrated an increase in autophagy signaling in pancreatic MCC tissues and the MCC1 cell line compared with adjacent tissues and normal human pancreatic ductal epithelium (HPDE) cells. In addition, abnormal autophagy activation facilitated the migration and invasion of MCC1 cells. MicroRNA (miR)-224-5p expression levels were significantly higher in MCC1 cells compared with those in HPDE cells. Treatment with rapamycin further demonstrated that high levels of autophagy elevated miR-224-5p expression in MCC1 cells in a time-dependent manner. BCL2 was identified as a downstream target gene of miR-224-5p, which binds to the 3′-untranslated region of BCL2. In addition, the results of the present study demonstrated that BCL2 knockdown reversed the inhibition of autophagy mediated by the miR-224-5p inhibitor. To the best of our knowledge, this is the first study to evaluate the role of autophagy in pancreatic MCC. Thus, these results suggested that autophagy may be hyperactivated in pancreatic MCC. In addition, the present study identified a positive feedback loop between autophagy signaling and miR-224-5p, which may promote the aggressive migration and invasion of MCC1. These results may provide a new insight into the relationship between autophagy and tumor metastasis in pancreatic MCC.