BCL-2 inhibitors sensitize therapy-resistant chronic lymphocytic leukemia cells to VSV oncolysis

Zinc Oxide Nanoparticles Induce Renal Injury by Initiating Oxidative Stress, Mitochondrial Damage and Apoptosis in Renal Tubular Epithelial Cells

Zinc oxide nanoparticles (ZnO NPs) are widely used in many fields due to their unique physicochemical properties. However, the renal toxicity of ZnO NPs and the underlying mechanisms have not been well studied. We found that ZnO NPs induced injury in human renal proximal tubular epithelial cells (HK-2) in a dose- and size-dependent manner, as revealed by CCK-8, LDH and Annexin V-FITC assays. Mechanistically, ZnO NPs promoted oxidative stress and mitochondrial damage by generating ROS and induced apoptosis in HK-2 cells, as evidenced by the upregulation of Bax and Caspase 3 and downregulation of Beclin 1. In vivo, ZnO NPs induced tubular epithelial cell apoptosis and increased serum creatinine, serum urea nitrogen, and urinary protein in mice, suggesting damage to renal structure and function. These findings clarified our understanding of the biological mechanisms underlying ZnO NP-induced renal tubular epithelial cell injury and contributed to estimating the risk of ZnO NPs to the kidney.

Oncolytic viruses in hematological malignancies: hijacking disease biology and fostering new promises for immune and cell-based therapies

The increased tropism for malignant cells of some viruses has been highlighted in recent studies, prompting their use as a strategy to modify the transcriptional profile of those cells, while sparing the healthy ones. Likewise, they have been recognized as players modulating microenvironmental immunity, namely through an increase in antigen-presenting, natural-killer, and T CD8+ cytotoxic cells by a cross-priming mechanism elicited by tumor-associated antigens. The immunomodulatory role of the oncolytic virus seems relevant in hematological malignancies, which may relapse as a result of a proliferative burst elicited by an external stimulus in progenitor or neoplastic stem cells. By reprogramming the host cells and the surrounding environment, the potential of virotherapy ranges from the promise to eradicate the minimal measurable disease (in acute leukemia, for example), to the ex vivo purging of malignant progenitor cells in the setting of autologous bone marrow transplantation. In this review, we analyze the recent advances in virotherapy in hematological malignancies, either when administered alone or together with chemotherapeutic agents or other immunomodulators.

Identification of an Autophagy-Related lncRNA Prognostic Signature and Related Tumor Immunity Research in Lung Adenocarcinoma

Autophagy is closely associated with the tumor immune microenvironment (TIME) and prognosis of patients with lung adenocarcinoma (LUAD). In the present study, we established a signature on the basis of long noncoding RNAs (lncRNAs) related to autophagy (ARlncRNAs) to investigate the TIME and survival of patients with LUAD. We selected ARlncRNAs associated with prognosis to construct a model and divided each sample into different groups on the basis of risk score. The ARlncRNA signature could be recognized as an independent prognostic factor for patients with LUAD, and patients in the low-risk group had a greater survival advantage. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analysis suggested that several immune functions and pathways were enriched in different groups. A high-risk score correlated significantly negatively with high abundance of immune cells and stromal cells around the tumor and high tumor mutational burden. Low-risk patients had a higher PD-1, CTLA-4, and HAVCR2 expression and had a better efficacy of immune checkpoint inhibitors, including PD-1/CTLA-4 inhibitor. A reliable signature on the basis of ARlncRNAs was constructed to explore the TIME and prognosis of patients with LUAD, which could provide valuable information for individualized LUAD treatment.

Oncolytic viruses as a promising therapeutic strategy for hematological malignancies

The incidence of hematological malignancies such as multiple myeloma, leukemia, and lymphoma has increased over time. Although bone marrow transplantation, immunotherapy and chemotherapy have led to significant improvements in efficacy, poor prognosis in elderly patients, recurrence and high mortality among hematological malignancies remain major challenges, and innovative therapeutic strategies should be explored. Besides directly lyse tumor cells, oncolytic viruses can activate immune responses or be engineered to express therapeutic factors to increase antitumor efficacy, and have gradually been recognized as an appealing approach for fighting cancers. An increasing number of studies have applied oncolytic viruses in hematological malignancies and made progress. In particular, strategies combining immunotherapy and oncolytic virotherapy are emerging. Various phase I clinical trials of oncolytic reovirus with lenalidomide or programmed death 1(PD-1) immune checkpoint inhibitors in multiple myeloma are ongoing. Moreover, preclinical studies of combinations with chimeric antigen receptor T (CAR-T) cells are underway. Thus, oncolytic virotherapy is expected to be a promising approach to cure hematological malignancies. This review summarizes progress in oncolytic virus research in hematological malignancies. After briefly reviewing the development and oncolytic mechanism of oncolytic viruses, we focus on delivery methods of oncolytic viruses, especially systemic delivery that is suitable for hematological tumors. We then discuss the main types of oncolytic viruses applied for hematological malignancies and related clinical trials. In addition, we present several ways to improve the antitumor efficacy of oncolytic viruses. Finally, we discuss current challenges and provide suggestions for future studies.

The Role of Vesicular Stomatitis Virus Matrix Protein in Autophagy in the Breast Cancer

BACKGROUND

Breast cancer is one of the most difficult malignancies to treat. Therapeutics is used to target and kill the cancer cells. Non-human oncolytic viruses have the ability to cause cell death directly to cancers. The objective here was to investigate the role of Vesicular Stomatitis Virus (VSV) Matrix (M) protein in autophagy in the breast cancer cell line.

METHODS

Two different VSV wild type and mutant (M51R) M protein constructs were produced. Breast cancer cell line BT-20 was transfected by either wild type or mutant vectors. Transfection efficiency was measured using a fluorescent microscopy. Expression of VSV M protein was investigated at protein level. Cell cytotoxicity was measured using an MTT assay. The autophagy pathway was studied by Beclin-1 immunoassay. Data were statistically analyzed between different transfected groups.

RESULTS

It has been shown that the VSV M protein induced higher levels of Beclin-1 than the M51R mutant in the BT-20 cell line. Increased levels of Beclin-1 were also associated with VSV M cell-induced cytotoxicity.

CONCLUSION

It has been shown here that VSV wild type or mutant M proteins can cause autophagy-induced cell death by increasing Beclin-1 expression. This includes the possible role of VSV to be used as an oncolytic virus in breast cancer treatment. <br />.

Efficient Delivery and Replication of Oncolytic Virus for Successful Treatment of Head and Neck Cancer

Head and neck cancer has been treated by a combination of surgery, radiation, and chemotherapy. In recent years, the development of immune checkpoint inhibitors (ICIs) has made immunotherapy a new treatment method. Oncolytic virus (OV) therapy selectively infects tumor cells with a low-pathogenic virus, lyses tumor cells by the cytopathic effects of the virus, and induces anti-tumor immunity to destroy tumors by the action of immune cells. In OV therapy for head and neck squamous cell carcinoma (HNSCC), viruses, such as herpes simplex virus type 1 (HSV-1), vaccinia virus, adenovirus, reovirus, measles virus, and vesicular stomatitis virus (VSV), are mainly used. As the combined use of mutant HSV-1 and ICI was successful for the treatment of melanoma, studies are underway to combine OV therapy with radiation, chemotherapy, and other types of immunotherapy. In such therapy, it is important for the virus to selectively replicate in tumor cells, and to express the viral gene and the introduced foreign gene in the tumor cells. In OV therapy for HNSCC, it may be useful to combine systemic and local treatments that improve the delivery and replication of the inoculated oncolytic virus in the tumor cells.

Chemical, Physical and Biological Triggers of Evolutionary Conserved Bcl-xL-Mediated Apoptosis

Background: The evidence that pan-Bcl-2 or Bcl-xL-specific inhibitors prematurely kill virus-infected or RNA/DNA-transfected cells provides rationale for investigating these apoptotic inducers further. We hypothesized that not only invasive RNA or DNA (biological factors) but also DNA/RNA-damaging chemical or physical factors could trigger apoptosis that have been sensitized with pan-Bcl-2 or Bcl-xL-specific agents; Methods: We tested chemical and physical factors plus Bcl-xL-specific inhibitor A-1155463 in cells of various origins and the small roundworms (C. elegans); Results: We show that combination of a A-1155463 along with a DNA-damaging agent, 4-nitroquinoline-1-oxide (4NQO), prematurely kills cells of various origins as well as C. elegans. The synergistic effect is p53-dependent and associated with the release of Bad and Bax from Bcl-xL, which trigger mitochondrial outer membrane permeabilization. Furthermore, we found that combining Bcl-xL-specific inhibitors with various chemical compounds or physical insults also induced cell death; Conclusions: Thus, we were able to identify several biological, chemical and physical triggers of the evolutionarily conserved Bcl-xL-mediated apoptotic pathway, shedding light on strategies and targets for novel drug development.

A multi-scale systems pharmacology approach uncovers the anti-cancer molecular mechanism of Ixabepilone

It has been realized that FDA approved drugs may have more molecular targets than is commonly thought. Thus, to find the exact drug-target interactions (DTIs) is of great significance for exploring the new molecular mechanism of drugs. Here, we developed a multi-scale system pharmacology (MSSP) method for the large-scale prediction of DTIs. We used MSSP to integrate drug-related and target-related data from multiple levels, the network structural data formed by known drug-target relationships for predicting likely unknown DTIs. Prediction results revealed that Ixabepilone, an epothilone B analog for treating breast cancer patients, may target Bcl-2, an oncogene that contributes to tumor progression and therapy resistance by inhibiting apoptosis. Furthermore, we demonstrated that Ixabepilone could bind with Bcl-2 and decrease its protein expression in breast cancer cells. The down-regulation of Bcl-2 by Ixabepilone is resulted from promoting its degradation by affecting p-Bcl-2. We further found that Ixabepilone could induce autophagy by releasing Beclin1 from Beclin1/Bcl-2 complex. Inhibition of autophagy by knockdown of Beclin1 or pharmacological inhibitor augmented apoptosis, thus enhancing the antitumor efficacy of Ixabepilone against breast cancer cells in vitro and in vivo. In addition, Ixabepilone also decreases Bcl-2 protein expression and induces cytoprotective autophagy in human hepatic carcinoma and glioma cells. In conclusion, this study not only provides a feasible and alternative way exploring new molecular mechanisms of drugs by combing computation DTI prediction, but also reveals an effective strategy to reinforce the antitumor efficacy of Ixabepilone.

Shikonin potentiates paclitaxel antitumor efficacy in esophageal cancer cells via the apoptotic pathway

Shikonin is a natural naphthoquinone pigment that can suppress the growth of a number of cancer cell types. Paclitaxel is an antineoplastic chemotherapy drug, which is used for the treatment of various types of solid tumor cancer. However, acquired paclitaxel resistance results in the failure of therapy, and consequent metastasis and relapse. The aim of the present study was to investigate whether shikonin can sensitize esophageal cancer cells to paclitaxel-treatment and to elucidate the underlying mechanisms. The biological effects of these two agents on esophageal cancer cell lines KYSE270 and KYSE150 were investigated by MTT assay, cell cycle analysis, Annexin-V apoptosis assay, western blotting and reverse transcription-quantitative polymerase chain reaction. The results demonstrated that shikonin could significantly increase the cell growth inhibition effect induced by paclitaxel in the examined cell lines (P<0.001). The addition of shikonin to paclitaxel promoted cancer cell mitotic arrest and induced significantly higher levels of cell apoptosis. Notably, the mRNA and protein levels of Bcl-2 were downregulated, while p53 was upregulated in KYSE270 and KYSE150 cells following combined treatment. In summary, shikonin can sensitize esophageal cancer cells to paclitaxel-treatment by promoting cell mitotic arrest and reinforcing the susceptibility of esophageal cancer cells to apoptosis induced by paclitaxel, which is potentially associated with altered levels of Bcl-2 and p53.

Plasmacytoid dendritic cells orchestrate innate and adaptive anti-tumor immunity induced by oncolytic coxsackievirus A21

BACKGROUND

The oncolytic virus, coxsackievirus A21 (CVA21), has shown promise as a single agent in several clinical trials and is now being tested in combination with immune checkpoint blockade. Combination therapies offer the best chance of disease control; however, the design of successful combination strategies requires a deeper understanding of the mechanisms underpinning CVA21 efficacy, in particular, the role of CVA21 anti-tumor immunity. Therefore, this study aimed to examine the ability of CVA21 to induce human anti-tumor immunity, and identify the cellular mechanism responsible.

METHODS

This study utilized peripheral blood mononuclear cells from i) healthy donors, ii) Acute Myeloid Leukemia (AML) patients, and iii) patients taking part in the STORM clinical trial, who received intravenous CVA21; patients receiving intravenous CVA21 were consented separately in accordance with local institutional ethics review and approval. Collectively, these blood samples were used to characterize the development of innate and adaptive anti-tumor immune responses following CVA21 treatment.

RESULTS

An Initial characterization of peripheral blood mononuclear cells, collected from cancer patients following intravenous infusion of CVA21, confirmed that CVA21 activated immune effector cells in patients. Next, using hematological disease models which were sensitive (Multiple Myeloma; MM) or resistant (AML) to CVA21-direct oncolysis, we demonstrated that CVA21 stimulated potent anti-tumor immune responses, including: 1) cytokine-mediated bystander killing; 2) enhanced natural killer cell-mediated cellular cytotoxicity; and 3) priming of tumor-specific cytotoxic T lymphocytes, with specificity towards known tumor-associated antigens. Importantly, immune-mediated killing of both MM and AML, despite AML cells being resistant to CVA21-direct oncolysis, was observed. Upon further examination of the cellular mechanisms responsible for CVA21-induced anti-tumor immunity we have identified the importance of type I IFN for NK cell activation, and demonstrated that both ICAM-1 and plasmacytoid dendritic cells were key mediators of this response.

CONCLUSION

This work supports the development of CVA21 as an immunotherapeutic agent for the treatment of both AML and MM. Additionally, the data presented provides an important insight into the mechanisms of CVA21-mediated immunotherapy to aid the development of clinical biomarkers to predict response and rationalize future drug combinations.

Recent advances in vesicular stomatitis virus-based oncolytic virotherapy: a 5-year update

Oncolytic virus (OV) therapy is an anti-cancer approach that uses viruses that preferentially infect, replicate in and kill cancer cells. Vesicular stomatitis virus (VSV, a rhabdovirus) is an OV that is currently being tested in the USA in several phase I clinical trials against different malignancies. Several factors make VSV a promising OV: lack of pre-existing human immunity against VSV, a small and easy to manipulate genome, cytoplasmic replication without risk of host cell transformation, independence of cell cycle and rapid growth to high titres in a broad range of cell lines facilitating large-scale virus production. While significant advances have been made in VSV-based OV therapy, room for improvement remains. Here we review recent studies (published in the last 5 years) that address 'old' and 'new' challenges of VSV-based OV therapy. These studies focused on improving VSV safety, oncoselectivity and oncotoxicity; breaking resistance of some cancers to VSV; preventing premature clearance of VSV; and stimulating tumour-specific immunity. Many of these approaches were based on combining VSV with other therapeutics. This review also discusses another rhabdovirus closely related to VSV, Maraba virus, which is currently being tested in Canada in phase I/II clinical trials.

Innovative Therapy, Monoclonal Antibodies and Beyond

The seventh Edition of "Innovative Therapy, Monoclonal Antibodies and Beyond" Meeting took place in Milan, Italy, on January 27, 2017. The two sessions of the meeting were focused on: 1) Preclinical assays and novel biotargets; and 2) monoclonal antibodies, cell therapies and targeted molecules. Between these two sessions, a lecture entitled "HLA-antigens modulation and response to immune checkpoint inhibitor immunotherapy" was also presented. Despite the impressive successes in cancer immunotherapy in recent years, the response to immune based interventions occurs only in a minority of patients (∼20%). Several basic and translational mechanisms of resistance to immune checkpoint blockers (ICBs) were discussed during the meeting: 1. the impact of tumor microenvironment on the activity of immune system; 2. strategies to inhibit the cross-talk between extracellular matrix and myeloid-derived suppressor cells (MDSC) in the preclinical setting; 3. microRNA expression as a biomarker and as a target of therapy in non-small cell lung cancer (NSCLC); 4. the significance of complement activation pathways in response to immune checkpoint inhibitors; 5. the immunosuppressive activity of the microbiota by inducing IL-17 producing cells; and 6. modulation of HLA antigens as possible markers of response to ICB therapy. In order to overcome the deficiency in active anti-tumor T cells, several clinically applicable combination strategies were also discussed: 1. strategies to enhance the anticancer effects of immunogenic cell death inducing-chemotherapy; 2. the use of CAR T-cells in solid tumors; 3. the use of combination strategies involving oncolytic viruses and ICBs; 4. combinations of new ICBs with anti-PD-1/CTLA-4 therapy; and 4. combinations of targeted therapies and ICBs in melanoma. Overall, this conference emphasized the many novel strategies that are being investigated to improve the overall patient response to cancer immunotherapy. Optimization of biomarkers to accurately select patients who will respond to immunotherapy, coupled with combination strategies to improve long term patient survival remain critical challenges in the immuno-oncology field.

Antiviral Properties of Chemical Inhibitors of Cellular Anti-Apoptotic Bcl-2 Proteins

Viral diseases remain serious threats to public health because of the shortage of effective means of control. To combat the surge of viral diseases, new treatments are urgently needed. Here we show that small-molecules, which inhibit cellular anti-apoptotic Bcl-2 proteins (Bcl-2i), induced the premature death of cells infected with different RNA or DNA viruses, whereas, at the same concentrations, no toxicity was observed in mock-infected cells. Moreover, these compounds limited viral replication and spread. Surprisingly, Bcl-2i also induced the premature apoptosis of cells transfected with viral RNA or plasmid DNA but not of mock-transfected cells. These results suggest that Bcl-2i sensitizes cells containing foreign RNA or DNA to apoptosis. A comparison of the toxicity, antiviral activity, and side effects of six Bcl-2i allowed us to select A-1155463 as an antiviral lead candidate. Thus, our results pave the way for the further development of Bcl-2i for the prevention and treatment of viral diseases.

Murine Tumor Models for Oncolytic Rhabdo-Virotherapy

The preclinical optimization and validation of novel treatments for cancer therapy requires the use of laboratory animals. Although in vitro experiments using tumor cell lines and ex vivo treatment of patient tumor samples provide a remarkable first-line tool for the initial study of tumoricidal potential, tumor-bearing animals remain the primary option to study delivery, efficacy, and safety of therapies in the context of a complete tumor microenvironment and functional immune system. In this review, we will describe the use of murine tumor models for oncolytic virotherapy using vesicular stomatitis virus. We will discuss studies using immunocompetent and immunodeficient models with respect to toxicity and therapeutic treatments, as well as the various techniques and tools available to study cancer therapy with Rhabdoviruses.

The intersection between viral oncolysis, drug resistance, and autophagy

Resistance to both cytotoxic and targeted therapies is a major problem facing cancer treatment. The mechanisms of resistance to unrelated drugs share many common features, including up-regulation of detoxifying pathways, activation of pro-survival mechanisms, and ineffective induction of cell death. Oncolytic viruses (OVs) are promising biotherapeutics for cancer treatment that specifically replicate in and lyse cancer cells. In addition to direct viral lysis, the anti-tumor effects of OVs are mediated via innate and adaptive immune responses, and several adaptation mechanisms such as autophagy appear to contribute to their anti-tumor properties. Autophagy is a versatile pathway that plays a key role in cancer survival during stressful conditions such as starvation or cytotoxic drug challenges. Autophagy also plays a role in mediating innate and adaptive immune responses by contributing to antigen presentation and cytokine secretion. This role of autophagy in regulation of immune responses can be utilized to design therapeutic combinations using approaches that either stimulate or block autophagy to potentiate therapeutic efficacy of OVs. Additional studies are needed to determine optimal multimodal combination approaches that will facilitate future successful clinical implementation of OV-based therapies.

Big Data Offers Novel Insights for Oncolytic Virus Immunotherapy

Large-scale assays, such as microarrays, next-generation sequencing and various “omics” technologies, have explored multiple aspects of the immune response following virus infection, often from a public health perspective. Yet a lack of similar data exists for monitoring immune engagement during oncolytic virus immunotherapy (OVIT) in the cancer setting. Tracking immune signatures at the tumour site can create a snapshot or longitudinally analyse immune cell activation, infiltration and functionality within global populations or individual cells. Mapping immune changes over the course of oncolytic biotherapy—from initial infection to tumour stabilisation/regression through to long-term cure or escape/relapse—has the potential to generate important therapeutic insights around virus-host interactions. Further, correlating such immune signatures with specific tumour outcomes has significant value for guiding the development of novel oncolytic virus immunotherapy strategies. Here, we provide insights for OVIT from large-scale analyses of immune populations in the infection, vaccination and immunotherapy setting. We analyse several approaches to manipulating immune engagement during OVIT. We further explore immunocentric changes in the tumour tissue following immunotherapy, and compile several immune signatures of therapeutic success. Ultimately, we highlight clinically relevant large-scale approaches with the potential to strengthen future oncolytic strategies to optimally engage the immune system.

Butorphanol, a synthetic opioid, sensitizes ABCB1-mediated multidrug resistance via inhibition of the efflux function of ABCB1 in leukemia cells

Multidrug resistance (MDR) remains a formidable challenge in the use of chemotherapy and represents a powerful obstacle to the treatment of leukemia. ATP-binding cassette subfamily B member 1 (ABCB1) is a recognized factor which causes MDR and is closely related to poor outcome and relapse in leukemia. Ongoing research concerning the strategy for inhibiting the abnormally high activity of the ABCB1 transporter is critically needed. In the present study, we sought to elucidate the interaction between ABCB1 transporter and butorphanol. Our results showed that butorphanol significantly antagonized ABCB1-mediated drug efflux and increased the intracellular drug concentration by inhibiting the transport activity of ABCB1 in leukemia cells. Mechanistic investigations demonstrated that butorphanol did not alter the protein expression or localization of ABCB1 in HL60/VCR and K562/ADR cells. Furthermore, homology modeling indicated that butorphanol could fit into the large drug-binding cavity of ABCB1 and form a binding conformation. In conclusion, butorphanol reversed the ABCB1-mediated MDR in leukemia cells by directly suppressing the efflux activity of ABCB1.

Role of high expression of IL-9 in prognosis of CLL

Chronic lymphocytic leukemia (CLL) is a common leukemia in adults, but its pathogenesis is still poorly understood. Interleukin-9 (IL-9) is initially described as a growth factor secreted by helper T cells. Recently, the oncogenic activities of IL-9 were reported in some leukemia but not chronic lymphocytic leukemia (CLL). The purpose of the present study is to investigate the expression of IL-9 from patients with CLL and to evaluate its correlation with clinical characteristics. Serum and peripheral blood mononuclear cells (PBMCs) from patients with CLL were analyzed using ELISA, RT-PCR, and western blot. ELISA analysis indicated IL-9 could be detected in 20 of 47 sera from CLL patients while none serum sample from healthy volunteers contained detectable levels of IL-9. There was a higher expression of IL-9 within PBMCs from patients with CLL compared with B cells of healthy blood donors using RT-PCR and western blot. The upregulated IL-9 was correlated to the clinical staging, ZAP-70 expression, β2 microglobulin expression and IgVH status of CLL patients (P<0.05). Our findings suggest that overexpression of IL-9 may contribute to the pathogenesis of CLL and is associated with some adverse prognostic parameters.

Histone deacetylase inhibitors potentiate vesicular stomatitis virus oncolysis in prostate cancer cells by modulating NF-κB-dependent autophagy

Vesicular stomatitis virus (VSV) is an oncolytic virus that induces cancer cell death through activation of the apoptotic pathway. Intrinsic resistance to oncolysis is found in some cell lines and many primary tumors as a consequence of residual innate immunity to VSV. In resistant-tumor models, VSV oncolytic potential can be reversibly stimulated by combination with epigenetic modulators, such as the histone deacetylase inhibitor vorinostat. Based on this reversible effect of vorinostat, we reasoned that critical host genes involved in oncolysis may likewise be reversibly regulated by vorinostat. A transcriptome analysis in prostate cancer PC3 cells identified a subset of NF-κB target genes reversibly regulated by vorinostat, as well as a group of interferon (IFN)-stimulated genes (ISGs). Consistent with the induction of NF-κB target genes, vorinostat-mediated enhancement of VSV oncolysis increased hyperacetylation of NF-κB RELA/p65. Additional bioinformatics analysis revealed that NF-κB signaling also increased the expression of several autophagy-related genes. Kinetically, autophagy preceded apoptosis, and apoptosis was observed only when cells were treated with both VSV and vorinostat. VSV replication and cell killing were suppressed when NF-κB signaling was inhibited using pharmacological or genetic approaches. Inhibition of autophagy by 3-methyladenine (3-MA) enhanced expression of ISGs, and either 3-MA treatment or genetic ablation of the autophagic marker Atg5 decreased VSV replication and oncolysis. Together, these data demonstrate that vorinostat stimulates NF-κB activity in a reversible manner via modulation of RELA/p65 signaling, leading to induction of autophagy, suppression of the IFN-mediated response, and subsequent enhancement of VSV replication and apoptosis.

Autophagy contributes to modulating the cytotoxicities of Bcl-2 homology domain-3 mimetics

The dysregulation of apoptosis is a key step in developing cancers, and mediates resistance to cancer therapy. Commitment to apoptosis is caused by permeabilization of the outer mitochondrial membrane, a process regulated by the interactions between different proteins of Bcl-2 family. Furthermore, Bcl-2 family proteins also bind to the endoplasmic reticulum, where they modulate autophagy, another important pathway regulating cell survival and death. Dysregulation of Bcl-2 family has been demonstrated in a wide spectrum of human cancers, including gastrointestinal cancers. Therefore, targeting the Bcl-2 family of proteins represents a promising therapeutic approach for these malignancies. Recent advances have yielded small molecules that have close structural or functional similarity to BH3-only proteins and are therefore named BH3 mimetics. Of these BH3 mimetics, obatoclax, (-)-gossypol, and ABT-263 are currently in clinical trials for multiple cancers. Growing evidence indicates that these BH3 mimetics not only induce apoptosis, but also regulate autophagy which may serve as a pro-survival or pro-death mechanism to counteract or mediate the cytotoxicity of BH3 mimetics. This review discusses the role of autophagy in cell-fate decision upon BH3 mimetics treatment. Further exploration of our understanding of the association between autophagy and cellular outcomes in response to BH3 mimetics treatment will likely offer improved therapies for patients with cancer.