Dysregulation of BCL-2 family proteins by leukemia fusion genes

The Role of Autophagy in the Function of CD4+ T Cells and the Development of Chronic Inflammatory Diseases

Uncontrolled acute inflammation progresses to persistent inflammation that leads to various chronic inflammatory diseases, including asthma, Crohn’s disease, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus. CD4⁺ T cells are key immune cells that determine the development of these chronic inflammatory diseases. CD4⁺ T cells orchestrate adaptive immune responses by producing cytokines and effector molecules. These functional roles of T cells vary depending on the surrounding inflammatory or anatomical environment. Autophagy is an important process that can regulate the function of CD4⁺ T cells. By lysosomal degradation of cytoplasmic materials, autophagy mediates CD4⁺ T cell-mediated immune responses, including cytokine production, proliferation, and differentiation. Furthermore, through canonical processes involving autophagy machinery, autophagy also contributes to the development of chronic inflammatory diseases. Therefore, a targeted intervention of autophagy processes could be used to treat chronic inflammatory diseases. This review focuses on the role of autophagy via CD4⁺ T cells in the pathogenesis and treatment of such diseases. In particular, we explore the underlying mechanisms of autophagy in the regulation of CD4⁺ T cell metabolism, survival, development, proliferation, differentiation, and aging. Furthermore, we suggest that autophagy-mediated modulation of CD4⁺ T cells is a promising therapeutic target for treating chronic inflammatory diseases.

Overcoming Steroid Resistance in Pediatric Acute Lymphoblastic Leukemia-The State-of-the-Art Knowledge and Future Prospects

Acute lymphoblastic leukemia (ALL) is the most common malignancy among children. Despite the enormous progress in ALL therapy, resulting in achieving a 5-year survival rate of up to 90%, the ambitious goal of reaching a 100% survival rate is still being pursued. A typical ALL treatment includes three phases: remission induction and consolidation and maintenance, preceded by a prednisone prephase. Poor prednisone response (PPR) is defined as the presence of ≥1.0 × 10⁹ blasts/L in the peripheral blood on day eight of therapy and results in significantly frequent relapses and worse outcomes. Hence, identifying risk factors of steroid resistance and finding methods of overcoming that resistance may significantly improve patients' outcomes. A mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK-ERK) pathway seems to be a particularly attractive target, as its activation leads to steroid resistance via a phosphorylating Bcl-2-interacting mediator of cell death (BIM), which is crucial in the steroid-induced cell death. Several mutations causing activation of MAPK-ERK were discovered, notably the interleukin-7 receptor (IL-7R) pathway mutations in T-cell ALL and rat sarcoma virus (Ras) pathway mutations in precursor B-cell ALL. MAPK-ERK pathway inhibitors were demonstrated to enhance the results of dexamethasone therapy in preclinical ALL studies. This report summarizes steroids' mechanism of action, resistance to treatment, and prospects of steroids therapy in pediatric ALL.

A systems genetics approach delineates the role of Bcl2 in leukemia pathogenesis

Leukemia is a group of malignancies of the blood forming tissues, and is characterized by the uncontrolled proliferation of blood cells. In the United States, it accounts for approximately 3.5% and 4% of all cancer-related incidences and mortalities, respectively. The current study aimed to explore the role of Bcl2 and associated genes in leukemia pathogenesis using a systems genetics approach. The transcriptome data from BXD Recombinant Inbred (RI) mice was analyzed to identify the expression of Bcl2 in myeloid cells. eQTL mapping was performed to select the potential chromosomal region and subsequently identify the candidate gene modulating the expression of Bcl2. Furthermore, gene enrichment and protein-protein interaction (PPI) analyses of the Bcl2-coexpressed genes were performed to demonstrate the role of Bcl2 in leukemia pathogenesis. The Bcl2-coexpressed genes were found to be enriched in various hematopoietic system related functions, and multiple pathways related to signaling, immune response, and cancer. The PPI network analysis demonstrated direct interaction of hematopoietic function related genes, such as Bag3, Bak1, Bcl2l11, Bmf, Mapk9, Myc, Ppp2r5c, and Ppp3ca with Bcl2. The eQTL mapping identified a 4.5 Mb genomic region on chromosome 11, potentially regulating the expression of Bcl2. A multi-criteria filtering process identified Top2a, among the genes located in the mapped locus, as the best candidate upstream regulator for Bcl2 expression variation. Hence, the current study provides better insights into the role of Bcl2 in leukemia pathogenesis and demonstrates the significance of our approach in gaining new knowledge on leukemia. Furthermore, our findings from the PPI network analysis and eQTL mapping provide supporting evidence of leukemia-associated genes, which can be further explored for their functional importance in leukemia. DATA AVAILABILITY: The myeloid cell transcriptomic data of the BXD mice used in this study can be accessed through our GeneNetwork (http://www.genenetwork.org) with the accession number of GN144.

Administration of Iodine-125 Seeds Promotes Apoptosis in Cholangiocarcinoma through the PI3K/Akt Pathway

Purpose. We aimed to examine the effects of 125I seeds on the gene expression of Bcl-2, Bax, and PI3K/Akt pathway components in cholangiocarcinoma cells. Methods. In vitro, human cholangiocarcinoma RBE cells were treated with 125I seeds (0.39 mCi or 0.85 mCi) for 72 h, 120 h, and 168 h. Cell proliferation and apoptosis were assessed. The expression of Bcl-2 and Bax was detected by RT-PCR, and Western blotting was carried out to explore changes in Akt activity. Result. 125I seeds inhibited the proliferation of RBE cells. The apoptosis rate of the RBE cells in the low-activity group was significantly higher than that in the high-activity group at 120 h and 168 h, while no difference was found between the two groups at 72 h. After 120 h of culture, the gene expression of Bcl-2 and Bax decreased in both groups, the ratio of $\text{Bcl}-2/\text{Bax}$ in the low-activity group decreased, and the PI3K/Akt signaling pathway was inhibited in both groups. Conclusion. 125I seeds affect the proliferation and apoptosis of cholangiocarcinoma cells in a dose-dependent manner. The therapeutic effect of low-activity 125I seeds on cancer cells may be better. 125I seed brachytherapy may promote the apoptosis of cholangiocarcinoma cells by inhibiting the PI3K/Akt signaling pathway and regulating the $\text{Bcl}-2/\text{Bax}$ ratio.

SFPQ-ABL1 and BCR-ABL1 utilize different signalling networks to drive B-cell acute lymphoblastic leukaemia

SFPQ-ABL1 is localized to the nuclear compartment and is a relatively weaker driver of cellular proliferation compared with BCR-ABL1.

SFPQ-ABL1 and BCR-ABL1 activate distinct signaling networks, both of which converge on inhibiting apoptosis and driving proliferation.

Philadelphia-like (Ph-like) acute lymphoblastic leukemia (ALL) is a high-risk subtype of B-cell ALL characterized by a gene expression profile resembling Philadelphia chromosome–positive ALL (Ph⁺ ALL) in the absence of BCR-ABL1. Tyrosine kinase–activating fusions, some involving ABL1, are recurrent drivers of Ph-like ALL and are targetable with tyrosine kinase inhibitors (TKIs). We identified a rare instance of SFPQ-ABL1 in a child with Ph-like ALL. SFPQ-ABL1 expressed in cytokine-dependent cell lines was sufficient to transform cells and these cells were sensitive to ABL1-targeting TKIs. In contrast to BCR-ABL1, SFPQ-ABL1 localized to the nuclear compartment and was a weaker driver of cellular proliferation. Phosphoproteomics analysis showed upregulation of cell cycle, DNA replication, and spliceosome pathways, and downregulation of signal transduction pathways, including ErbB, NF-κB, vascular endothelial growth factor (VEGF), and MAPK signaling in SFPQ-ABL1–expressing cells compared with BCR-ABL1–expressing cells. SFPQ-ABL1 expression did not activate phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling and was associated with phosphorylation of G2/M cell cycle proteins. SFPQ-ABL1 was sensitive to navitoclax and S-63845 and promotes cell survival by maintaining expression of Mcl-1 and Bcl-xL. SFPQ-ABL1 has functionally distinct mechanisms by which it drives ALL, including subcellular localization, proliferative capacity, and activation of cellular pathways. These findings highlight the role that fusion partners have in mediating the function of ABL1 fusions.

MicroRNA-221 regulates cell activity and apoptosis in acute lymphoblastic leukemia via regulating PTEN

T cell acute lymphoblastic leukemia (T-ALL), an aggressive and heterogeneous malignancy originating from T cell precursors (thymocytes), accounts for ~15% of all ALL cases in children and for ~25% in adults. The present study aimed to investigate the role of microRNA-221 (miR-221) in the regulation of cell viability and apoptosis of human T-ALL cells and its related regulatory mechanisms. To perform this investigation, miR-221 was upregulated or knocked down in human T-ALL cells (Jurkat cells) using miR-221 mimic or inhibitor, respectively. Then, cell viability was determined using a 3-(4,5-dimethylthiahiazol-2-y1)-2,5-diphenytetrazolium bromide assay, cell invasion and migration were analyzed via Transwell assays, and cell apoptosis was detected using flow cytometry. It was found that transfection with a miR-221 inhibitor significantly inhibited Jurkat cell viability, migration and invasion, and induced Jurkat cell apoptosis. Whereas, transfection with the miR-221 mimic resulted in the opposite effects. Besides, the results showed that phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was a target of miR-221. Moreover, it was observed that the effects of the miR-221 inhibitor on Jurkat cell viability, migration and invasion, and cell apoptosis were significantly eliminated by PTEN-small interfering RNA. In addition, it was shown that the phosphatidylinositol 3-kinase/AKT pathway was involved in the effect of miR-221 on Jurkat cells. In conclusion, the data indicated that miR-221 existed as an oncogene in T-ALL, and its downregulation could inhibit the development of ALL by targeting PTEN. Therefore, miR-221 may be a novel potential therapeutic target for ALL.

MCL-1 Inhibition Overcomes Anti-apoptotic Adaptation to Targeted Therapies in B-Cell Precursor Acute Lymphoblastic Leukemia

Multiple targeted therapies are currently explored for pediatric and young adult B-cell precursor acute lymphoblastic leukemia (BCP-ALL) treatment. However, this new armamentarium of therapies faces an old problem: choosing the right treatment for each patient. The lack of predictive biomarkers is particularly worrying for pediatric patients since it impairs the implementation of new treatments in the clinic. In this study, we used the functional assay dynamic BH3 profiling (DBP) to evaluate two new treatments for BCP-ALL that could improve clinical outcome, especially for relapsed patients. We found that the MEK inhibitor trametinib and the multi-target tyrosine kinase inhibitor sunitinib exquisitely increased apoptotic priming in an NRAS-mutant and in a KMT2A-rearranged cell line presenting a high expression of FLT3, respectively. Following these observations, we sought to study potential adaptations to these treatments. Indeed, we identified with DBP anti-apoptotic changes in the BCL-2 family after treatment, particularly involving MCL-1 - a pro-survival strategy previously observed in adult cancers. To overcome this adaptation, we employed the BH3 mimetic S63845, a specific MCL-1 inhibitor, and evaluated its sequential addition to both kinase inhibitors to overcome resistance. We observed that the metronomic combination of both drugs with S63845 was synergistic and showed an increased efficacy compared to single agents. Similar observations were made in BCP-ALL KMT2A-rearranged PDX cells in response to sunitinib, showing an analogous DBP profile to the SEM cell line. These findings demonstrate that rational sequences of targeted agents with BH3 mimetics, now extensively explored in clinical trials, may improve treatment effectiveness by overcoming anti-apoptotic adaptations in BCP-ALL.

Cotargeting BCL-2 and MCL-1 in high-risk B-ALL

Improving survival outcomes in adult B-cell acute lymphoblastic leukemia (B-ALL) remains a clinical challenge. Relapsed disease has a poor prognosis despite the use of tyrosine kinase inhibitors (TKIs) for Philadelphia chromosome positive (Ph+ ALL) cases and immunotherapeutic approaches, including blinatumomab and chimeric antigen receptor T cells. Targeting aberrant cell survival pathways with selective small molecule BH3-mimetic inhibitors of BCL-2 (venetoclax, S55746), BCL-XL (A1331852), or MCL1 (S63845) is an emerging therapeutic option. We report that combined targeting of BCL-2 and MCL1 is synergistic in B-ALL in vitro. The combination demonstrated greater efficacy than standard chemotherapeutics and TKIs in primary samples from adult B-ALL with Ph+ ALL, Ph-like ALL, and other B-ALL. Moreover, combined BCL-2 or MCL1 inhibition with dasatinib showed potent killing in primary Ph+ B-ALL cases, but the BH3-mimetic combination appeared superior in vitro in a variety of Ph-like ALL samples. In PDX models, combined BCL-2 and MCL1 targeting eradicated ALL from Ph- and Ph+ B-ALL cases, although fatal tumor lysis was observed in some instances of high tumor burden. We conclude that a dual BH3-mimetic approach is highly effective in diverse models of high-risk human B-ALL and warrants assessment in clinical trials that incorporate tumor lysis precautions.

Intrinsic and extrinsic apoptosis responses in leukaemia cells following daunorubicin treatment

BACKGROUND

Daunorubicin is used clinically in the treatment of myeloma, acute lymphatic and myelocytic leukaemia. The toxic lesions caused by daunorubicin induce various modes of cell death, including apoptosis. Apoptosis is highly regulated programmed cell death that can be initiated mainly via two pathways, through death receptors (extrinsic) or involvement of the mitochondria (intrinsic). Induction of apoptosis via these pathways has been alluded following treatment with daunorubicin, but never compared in acute lymphoblastic leukaemia over a time course.

METHODS

This study investigated the mechanisms of daunorubicin induced apoptosis in the treatment of CCRF-CEM, MOLT-4 (acute T-lymphoblastic leukaemia) and SUP-B15 (acute B-lymphoblastic leukaemia) cells. Cells were treated with daunorubicin for 4 h, and then placed in recovery medium (without daunorubicin) for 4 h, 12 h and 24 h. Apoptotic response was analysing using annexin-V expression, caspase activity, mitochondrial membrane potential change and an array to detect 43 apoptotic proteins.

RESULTS

Daunorubicin induced apoptosis in all leukemic cell lines, but with different levels and duration of response. Both apoptosis levels and caspase activity increased after four hours recovery then declined in CCRF-CEM and MOLT-4 cells. However, SUP-B15 cells displayed initially comparable levels but remained elevated over the 24 h assessment period. Changes in mitochondrial membrane potential occurred in both MOLT-4 and CCRF-CEM cells but not in SUP-B15 cells. Expression of apoptotic proteins, including Bcl-2, Bax, caspase 3 and FADD, indicated that daunorubicin potentially induced both extrinsic and intrinsic apoptosis in both CCRF-CEM and MOLT-4 cells, but only extrinsic apoptosis in SUP-B15 cells.

CONCLUSIONS

This study describes variations in sensitivities and timing of apoptotic responses in different leukaemia cell lines. These differences could be attributed to the lack of functional p53 in coordinating the cells response following cytotoxic treatment with daunorubicin, which appears to delay apoptosis and utilises alternative signalling mechanisms that need to be further explored.

Effect of MT2A on apoptosis and proliferation in HL60 cells

Although accumulating evidence has revealed that metallothioneins (MTs) and its family member MT2A are strongly linked to the risk of various solid tumors, researches on the occurrence and development of acute myeloid leukemia (AML) have rarely been investigated. Here, we constructed a lentiviral vector with MT2A over-expression and the interfering plasmids with MT2A expression inhibition to study the influence of MT2A on the bioactivities of HL60 cells. After cells were infected with a lentiviral vector containing the MT2A gene, both transcription and translation levels of MT2A were significantly increased in the over-expressed group in comparison with control groups. In vitro experiments, all results demonstrated that cell reproductive capacity was inhibited, but cell apoptosis rate was significantly increased. Together, the expression of apoptosis-related protein Bcl2 was remarkably reduced, while a high expression level of Bax protein was detected. Further experiments revealed that up-regulation of MT2A induced cell apoptosis and promoted G2/M phase arrest. The mechanism may be associated with down-regulated p-IκB-α and cyclinD1 expression and up-regulated IκB-α expression in the nuclear factor-kappaB (NF-κB) pathway. On the contrary, MT2A expression was down-regulated by interfering plasmids. We found that cell proliferative potential was notably increased in the interfering group compared with the negative and untreated group. What's more, MT2A may be closely related to AML cell proliferation and function via the NF-κB signal pathway.

Synthetically Engineered Adeno-Associated Virus for Efficient, Safe, and Versatile Gene Therapy Applications

Gene therapy directly targets mutations causing disease, allowing for a specific treatment at a molecular level. Adeno-associated virus (AAV) has been of increasing interest as a gene delivery vehicle, as AAV vectors are safe, effective, and capable of eliciting a relatively contained immune response. With the recent FDA approval of two AAV drugs for treating rare genetic diseases, AAV vectors are now on the market and are being further explored for other therapies. While showing promise in immune privileged tissue, the use of AAV for systemic delivery is still limited due to the high prevalence of neutralizing antibodies (nAbs). To avoid nAb-mediated inactivation, engineered AAV vectors with modified protein capsids, materials tethered to the capsid surface, or fully encapsulated in a second, larger carrier have been explored. Many of these engineered AAVs have added benefits, including avoided immune response, overcoming the genome size limit, targeted and stimuli-responsive delivery, and multimodal therapy of two or more therapeutic modalities in one platform. Native and engineered AAV vectors have been tested to treat a broad range of diseases, including spinal muscular atrophy, retinal diseases, cancers, and tissue damage. This review will cover the benefits of AAV as a promising gene vector by itself, the progress and advantages of engineered AAV vectors, particularly synthetically engineered ones, and the current state of their clinical translation in therapy.

Enhancement of leukemia-like phenotypes in Drosophila mxc mutant larvae due to activation of the RAS-MAP kinase cascade possibly via down-regulation of DE-cadherin

Loss of mxc gene function in mature hemocytes of Drosophila mxc^mbn1 mutant results in malignant hyperplasia in larval hematopoietic tissues termed lymph glands (LGs) owing to over-proliferation of immature cells. This is a useful model for genetic analyses of leukemia progression. To identify other mutations that deteriorate the hyperplasia, we aimed to investigate whether hyper-activation of common signaling cascade enabled to enhance the phenotypes. Ectopic expression of the constitutively active forms of MAPK signaling factors in the mutant increased the hyperplasia and the number of circulating hemocytes, resulting in the production of LG fragments. The LG phenotype was related to the reduced DE-cadherin level in the mutants. Depletion of Drosophila MCRIP, involved in MAPK-induced silencing of cadherin gene expression, exhibited a similar enhancement of the mxc^mbn1 phenotypes. Furthermore, expression of MMP1 proteinase that cleaves the extracellular matrix proteins increased in the mutant larvae harboring MAPK cascade activation. Depletion of Mmp1 and that of pnt (required for Mmp1 expression) suppressed the LG hyperplasia. Hence, we speculated that reduction in DE-cadherin level by either down-regulation of MCRIP or up-regulation of MMP1 was involved in the progression of the tumor phenotype. Our findings can contribute to understanding the mechanism underlying human leukemia progression.

miR‑378 in combination with ultrasonic irradiation and SonoVue microbubbles transfection inhibits hepatoma cell growth

Ultrasonic microbubbles in combination with microRNA (miRNAs/miRs) exhibited promising effects on cancer treatments. The aim was to investigate the role of miR-378 in hepatoma cells and the efficiency of it in combination with ultrasonic irradiation and SonoVue^® microbubbles method for cell transfection. HuH-7, Hep3B and SK-Hep1 cells were transfected with an miR-378 mimic using only Lipofectamine^® 3000 or combined with SonoVue microbubbles and ultrasonic irradiation at 0.5 W/cm² for 30 sec. mRNAs and protein levels of Cyclin D1, Bcl-2, Bax, Akt, p53 and Survivin were detected by reverse transcription-quantitative PCR and western blotting, respectively. Cell survival rate, proliferation, cell cycle and apoptosis were determined by Cell Counting Kit-8, cell double cytochemical staining and flow cytometry, respectively. It was found that using a combination of ultrasonic irradiation and the SonoVue microbubbles method increased the effectiveness of miR-378 transfection into hepatocellular carcinoma (HCC) cells, and increased the inhibition of cell survival and proliferation. Moreover, miR-378 increased the rate of apoptosis and upregulated the expression of Bax and p53, and suppressed the cell cycle and downregulated the expression of Cyclin D1, Bcl-2, Akt, β-catenin and Survivin much more effectively in the HCC cell line by applying the combined method. Thus, miR-378 was shown to be a suppressive factor to reduce proliferation and increase apoptosis in HCC cells. Additionally, the combination of ultrasonic irradiation and SonoVue microbubbles method was more efficient in the transfection of miRNA.

Effects of resveratrol on learning and memory in rats with vascular dementia

The purpose of the present study was to study the effects of resveratrol on cognitive function in rats with vascular dementia and to investigate the molecular mechanisms of its neuroprotective effects. Forty-five SD rats were randomly divided into 3 groups: The control group (Con group, n=15), the model group (VD group, n=15) and the resveratrol-treated VD group (Res group, n=15). The VD rats (the VD group and the Res group) were generated by bilateral common carotid artery occlusion. The rats in the Res group received daily resveratrol treatment intraperitoneally for 4 weeks. Cognitive function was tested using the Morris water maze test. The levels of SOD and MDA (oxidative stress indicators) were detected by ELISA kits. The protein expression of Bax, Bcl-2 and caspase-3 was detected by western blotting. Compared with the rats in the Con group, the rats in the VD group exhibited decreased cognitive function, significantly increased hippocampal content of MDA, Bax and caspase-3 (P<0.05), and significantly reduced hippocampal expression of SOD and Bcl-2 (P<0.05). Compared with the rats in the VD group, the rats in the Res group exhibited increased cognitive ability, reduced hippocampal content of MDA, Bax and caspase-3 (P<0.05), and increased hippocampal expression of SOD and Bcl-2 (P<0.05). Resveratrol treatment significantly improved the spatial learning and memory of the VD rats. The mechanism associated with the neuroprotective effects of resveratrol may be closely related to the inhibition of the apoptosis pathway and oxidative stress injury.

Mitochondria as emerging targets for therapies against T cell acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) comprises a heterogeneous group of hematologic malignancies, arising from diverse genetic alterations in the early lymphocyte development. T-cell subtype of ALL (T-ALL) accounts for about 15% and 25% of ALL in children and adults, respectively. Being less frequent among ALL subtypes, T-ALL represents a high-risk factor for poor prognosis due to its aggressiveness and resistance to common antileukemic drugs. Mitochondria were widely explored recently as a target for anticancer treatment because they are involved in a metabolic reprogramming of a cancer cell and play key roles in reactive oxygen species generation, Ca²⁺ signaling, and cell death induction. Accordingly, a new class of anticancer compounds named mitocans has been developed, which target mitochondria at distinct crucial points to promote their dysfunction and subsequent cell death. The present review analyses the role of mitochondria in malignant reprogramming and emerging therapeutic strategies targeting mitochondria as an "Achilles' heel" in T-ALL, with an emphasis on BH3 mimetics, sequestering pro-survival BCL proteins and voltage-dependent anion channel (VDAC)1-directed drugs, which promote the suppression of aerobic glycolysis, VDAC1 closure, mitochondrial Ca²⁺ overload, stoppage of the oxidative phosphorylation, oxidative stress, and release of proapoptotic factors.

Downregulation of microRNA-1 attenuates glucose-induced apoptosis by regulating the liver X receptor α in cardiomyocytes

Diabetic cardiomyopathy (DCM) is characterized by abnormal myocardial structure or performance. It has been suggested that microRNA-1 (miR-1) may be abnormally expressed in the hearts of patients with diabetes. In the present study, the role of miR-1 in glucose-induced apoptosis and its underlying mechanism of action was investigated in rat cardiomyocyte H9C2 cells. Cells were transfected with anti-miR-1 or miR-1-overexpression plasmids and the expression of miR-1 and liver X receptor α (LXRα) were determined by reverse transcription-quantitative polymerase chain reaction analysis. The proportion of apoptotic cells was determined using an Annexin-V-FITC apoptosis detection kit and the mitochondrial membrane potential (ΔΨ) was measured following staining with rhodamine 123. In addition, the expression of apoptosis-associated proteins was measured by western blot analysis. The results demonstrated that expression of miR-1 was significantly increased, whereas the expression of LXRα was significantly decreased in H9C2 cells following treatment with glucose. miR-1 knockdown significantly inhibited apoptosis, increased the ΔΨ and suppressed the cleavage of poly (adenosine diphosphate-ribose) polymerase, caspase-3 and caspase-9. It also significantly downregulated the expression of Bcl-2 and upregulated the expression of Bax. In addition, it was demonstrated that miR-1 regulates LXRα; transfection with anti-miR-1 significantly increased the expression of LXRα. Furthermore, treatment of cells with the LXR agonist GW3965 inhibited apoptosis in glucose-induced anti-miR-1 cells. These results suggest a novel function of miR-1: The regulation of cardiomyocyte apoptosis via LXRα, and provide novel insights into regarding the complex mechanisms involved in DCM.

Immediate early response gene 5 promotes irradiation combined with cisplatin-induced apoptosis in HeLa cells

The objective of this study was to explore the action and mechanism of immediate early response gene 5 (IER5) on the apoptosis induced by irradiation combined with cisplatin in HeLa cells. The IER5 gene was knocked down using IER5-specific small interfering (si)RNA to generate HeLa cells stably expressing low levels of IER5 (HeLa-siIER5). Apoptosis was induced by ⁶⁰Co γ-radiation, cisplatin, and radiation combined with cisplatin. Apoptosis and cell viability were evaluated by flow cytometry and Cell Counting Kit-8, respectively. Protein expression was determined by western blotting. Apoptosis was significantly inhibited in HeLa-siIER5 cells after γ-radiation combined with cisplatin exposure compared with siRNA control cells (P < 0.01). We also found that the expression of Bcl-2 was increased, and the levels of cleaved caspase-9 and cleaved PARP were reduced after γ-radiation combined with cisplatin treatment of HeLa-siIER5 cells. These results indicated that decreased expression of IER5 can reduce apoptosis induced by exposure to γ-radiation combined with cisplatin. Enhancing the expression of IER5 in tumor cells, and reducing its expression in normal cells, may be utilized as targeting strategies to improve the outcomes of chemo/radiotherapy for the treatment of patients with cervical cancer.