PUMA and NF-kB Are Cell Signaling Predictors of Reovirus Oncolysis of Breast Cancer

Oncolytic viruses as emerging therapy against cancers including Oncovirus-induced cancers

There are several human viruses with known potential for causing cancers including, Hepatitis B virus, Hepatitis C virus, Epstein-Barr virus, Kaposi's sarcoma herpesvirus, Human T-cell lymphotropic virus, Human papillomavirus, and Merkel cell polyomavirus. Cancer is the second leading cause of death that affects humans worldwide, especially in developing countries. Surgery, chemotherapy, and radiotherapy can cure about 60% of humans with cancer but recurrent and metastatic diseases remain a major reason for death. In recent years, understanding the molecular characteristics of cancer cells has led to the improvement of therapeutic strategies using novel emerging therapies. Oncolytic viruses with the potential of lysing cancer cells defined the field of oncolytic virology, hence becoming a biotechnology tool rather than just a cause of disease. This study mainly focused on targeting cell proliferation and death pathways in human tumor-inducing viruses by developing innovative therapies for cancer patients based on the natural oncolytic properties of reovirus. To kill tumor cells efficiently and reduce the chance of recurrence both the direct ability of reovirus infection to lyse the tumor cells and the stimulation of a potent host immune response are applied. Hence, bioengineered stem cells can be used as smart carriers to improve the efficacy of oncolytic reovirus and safety profiles.

Therapeutic potential of phospho-thiadiazole derivatives as anti-glioblastoma agents: synthesis, biological assessment and computational study

In this study, three new phospho thiadiazole compounds (A, F and W) were investigated as possible cytotoxic agents. The compounds were synthesised and characterised by using spectroscopy methods. The crystal structure of compound A was investigated using X-ray crystallography, since the title compounds can exist as different tautomeric forms, their conformational and geometrical aspects were investigated computationally by the DFT method. NBO analysis suggested that these compounds can function as appropriate ligands for the reaction with the nitrogen bases of DNA. All the synthesised compounds were evaluated in vitro for their cytotoxic activities against cancer in the human glioblastoma cell lines (U-251) using the MTT assay. According to the annexin V-FITC/PI results, a combination of synthesised compounds with ReoT3D showed a synergistic effect to increase the percentage of apoptotic cells. Molecular docking study for A (the most toxic compound) showed how it interacts with DNA. Both in vitro and in silico results showed that A has promising inhibitory potential (IC₅₀: 48.1 ± 0.3 μM) and binding energy (-6.67 kcal/mol).

Reovirus Activated Cell Death Pathways

Mammalian orthoreoviruses (ReoV) are non-enveloped viruses with segmented double-stranded RNA genomes. In humans, ReoV are generally considered non-pathogenic, although members of this family have been proven to cause mild gastroenteritis in young children and may contribute to the development of inflammatory conditions, including Celiac disease. Because of its low pathogenic potential and its ability to efficiently infect and kill transformed cells, the ReoV strain Type 3 Dearing (T3D) is clinical trials as an oncolytic agent. ReoV manifests its oncolytic effects in large part by infecting tumor cells and activating programmed cell death pathways (PCDs). It was previously believed that apoptosis was the dominant PCD pathway triggered by ReoV infection. However, new studies suggest that ReoV also activates other PCD pathways, such as autophagy, pyroptosis, and necroptosis. Necroptosis is a caspase-independent form of PCD reliant on receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and its substrate, the pseudokinase mixed-lineage kinase domain-like protein (MLKL). As necroptosis is highly inflammatory, ReoV-induced necroptosis may contribute to the oncolytic potential of this virus, not only by promoting necrotic lysis of the infected cell, but also by inflaming the surrounding tumor microenvironment and provoking beneficial anti-tumor immune responses. In this review, we summarize our current understanding of the ReoV replication cycle, the known and potential mechanisms by which ReoV induces PCD, and discuss the consequences of non-apoptotic cell death—particularly necroptosis—to ReoV pathogenesis and oncolysis.

Mesenchymal stem cells loaded with oncolytic reovirus enhances antitumor activity in mice models of colorectal cancer

Oncolytic viruses (OVs) are promising alternative biological agents for treating cancer. However, triggered immune responses against viruses and their delivery to tumor sites are their primary limitations in cancer therapy. To address these challenges, mesenchymal stem cells (MSCs) can serve as permissive tools for OVs loading and delivery to tumor sites. Here, we evaluated the in vitro and in vivo antitumor capability of adipose-derived mesenchymal stem cells (AD-MSCs) as a new vehicle for Dearing strain of reovirus (ReoT3D) loading. We first isolated and confirmed the purity of MSCs, and the optimized dose of ReoT3D for MSCs loading was computed by a standard assay. Next, we used murine CT26 cell line to establish the colorectal cancer model in BALB/c mice and demonstrated the antitumor effects of MSCs loaded with reovirus. Our results demonstrated that multiplicity of infection (MOI) 1 pfu/cells of reovirus was the safe dose for loading into purified MSCs. Moreover, our anticancer experiments exhibited that treatment with MSCs loaded with ReoT3D was more effective than ReoT3D and MSCs alone. Higher anticancer impact of MSCs loaded with OV was associated with induction of apoptosis, cell cycle arrests, P53 expression in tumor sections, and reduced tumor growth and size. The present results suggest that MSCs as a permissive shuttle for oncolytic virus (OV) delivery increased the anticancer activity of ReoT3D in mice models of colorectal cancer and these findings should be supported by more preclinical and clinical studies.

MSCs loaded with oncolytic reovirus: migration and in vivo virus delivery potential for evaluating anti-cancer effect in tumor-bearing C57BL/6 mice

Background and aims

Several oncolytic viruses applications have been approved in the clinic or in different phases of clinical trials. However, these methods have some rudimentary problems. Therefore, to enhance the delivery and quality of treatment, considering the advantage of cell carrier-based methods such as Mesenchymal Stem Cells (MSC) have been proposed. This study was designed to evaluate the performance and quality of cancer treatment based on MSCs loaded by oncolytic reovirus in the cancerous C57BL/6 mouse model. Also, we evaluated MSCs migration potency in vitro and in vivo following the oncolytic reovirus infection.

Methods

C57BL/6 mice were inoculated with TC-1 cell lines and tumors were established in the right flank. Mice were systemically treated with reovirus, MSCs-loaded with reovirus, MSCs, and PBS as a control in separated groups. Effects of infected AD-MSCs with reovirus on tumor growth and penetration in the tumor site were monitored. All groups of mice were monitored for two months in order to therapeutic and anticancer potential. After treatments, tumor size alteration and apoptosis rate, as well as cytokine release pattern was assessed.

Results

The results of the current study indicated that the effect of reovirus infection on AD-MSCs is not devastating the migration capacity especially in MOI 1 and 5 while intact cells remain. On the other hand, MSCs play an efficient role as a carrier to deliver oncolytic virus into the tumor site in comparison with systemic administration of reovirus alone. Apoptosis intensity relies on viral titration and passing time. Followed by systemic administration, treatment with oncolytic reovirus-infected AD-MSCs and MSCs alone had shown significant inhibition in tumor growth. Also, treatment by reovirus causes an increase in IFN-γ secretion.

Conclusion

The results of in vitro and in vivo study confirmed the tumor-homing properties of infected AD-MSCs and the significant antitumor activity of this platform. Hence, our results showed that the cell carrier strategy using oncolytic reovirus-loaded AD-MSCs enhanced virus delivery, infiltration, and antitumor activity can be effectively applied in most cancers.

Mesenchymal stem cell carriers enhance antitumor efficacy induced by oncolytic reovirus in acute myeloid leukemia

Chemotherapy is the main treatment for acute myeloid leukemia (AML), but the therapeutic efficacy is modest, and most commonly manifests as relapse from remission. Thus, improving long-term AML survival is a crucial clinical challenge. In recent years, oncolytic virotherapy has provided an alternative approach for AML treatment. The use of oncolytic reoviruses has been explored in more than 30 clinical trials for safety and feasibility issues. However, like other oncolytic viruses, neutralizing antibodies (NAbs) reduce therapeutic efficacy. To tackle this problem, human umbilical cord mesenchymal stem cells (hUC-MSCs) were used to deliver reovirus using in vitro and in vivo models. Human UC-MSCs were successfully loaded with reovirus, without impairing biological function.We also observed in vitro protective effects of hUC-MSCs on reovirus in the presence of NAbs. In the immunocompromised AML mouse model, hUC-MSCs effectively carried reoviruses to tumor lesions and significantly prolonged the survival of AML xenografts in mice in the presence of a high titer anti-reovirus antibody (p = 0.001). However, reovirus-induced activation of AKT, stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), and NF-κB signaling led to the maintenance of intrinsic migratory properties and secretion of pro-inflammatory cytokines from hUC-MSCs, particularly CXCL10. In immuno-competent AML mice, MSCs carrying reovirus triggered immune responses, and eventually inhibited tumor growth. Therefore, these results suggest that MSCs as carriers of oncolytic reoviruses can enhance the antitumor efficacy of virotherapy.

Closely related reovirus lab strains induce opposite expression of RIG-I/IFN-dependent versus -independent host genes, via mechanisms of slow replication versus polymorphisms in dsRNA binding σ3 respectively

The Dearing isolate of Mammalian orthoreovirus (T3D) is a prominent model of virus-host relationships and a candidate oncolytic virotherapy. Closely related laboratory strains of T3D, originating from the same ancestral T3D isolate, were recently found to exhibit significantly different oncolytic properties. Specifically, the T3DPL strain had faster replication kinetics in a panel of cancer cells and improved tumor regression in an in vivo melanoma model, relative to T3DTD. In this study, we discover that T3DPL and T3DTD also differentially activate host signalling pathways and downstream gene transcription. At equivalent infectious dose, T3DTD induces higher IRF3 phosphorylation and expression of type I IFNs and IFN-stimulated genes (ISGs) than T3DPL. Using mono-reassortants with intermediate replication kinetics and pharmacological inhibitors of reovirus replication, IFN responses were found to inversely correlate with kinetics of virus replication. In other words, slow-replicating T3D strains induce more IFN signalling than fast-replicating T3D strains. Paradoxically, during co-infections by T3DPL and T3DTD, there was still high IRF3 phosphorylation indicating a phenodominant effect by the slow-replicating T3DTD. Using silencing and knock-out of RIG-I to impede IFN, we found that IFN induction does not affect the first round of reovirus replication but does prevent cell-cell spread in a paracrine fashion. Accordingly, during co-infections, T3DPL continues to replicate robustly despite activation of IFN by T3DTD. Using gene expression analysis, we discovered that reovirus can also induce a subset of genes in a RIG-I and IFN-independent manner; these genes were induced more by T3DPL than T3DTD. Polymorphisms in reovirus σ3 viral protein were found to control activation of RIG-I/ IFN-independent genes. Altogether, the study reveals that single amino acid polymorphisms in reovirus genomes can have large impact on host gene expression, by both changing replication kinetics and by modifying viral protein activity, such that two closely related T3D strains can induce opposite cytokine landscapes.

The synergistic anticancer effects of ReoT3D, CPT-11, and BBI608 on murine colorectal cancer cells

BACKGROUND

Many types of oncolytic viruses (OVs) were enrolled in clinical trials. Recently, an OV named Talimogene laherparepvec approved for the treatment of melanoma. This achievement highlighted the clinical application of OVs. Scientists focus on using these anticancer agents in combination with the current or/and new anticancer chemotherapeutics. They aim to increase the oncolytic effect of a new approach for the treatment of cancer cells.

OBJECTIVES

The present study aimed to assess the anticancer impacts of ReoT3D, irinotecan (CPT-11), and napabucasin (BBI608) against murine colorectal cancer cells (CT26). They are assessed alone and in combination with each other.

METHODS

Here, oncolytic reovirus was propagated and titrated. Then MTT assay was carried out to assess the toxicity of this OV and chemotherapeutics effect on CT26 cells. The anticancer effects of ReoT3D, CPT-11, and BBI608, alone and simultaneously, on CT26 cell line, were assessed by the induction of apoptosis, cell cycle arrest, colony-forming, migration, and real-time PCR experiments.

RESULTS

Alone treatment with ReoT3D, CPT-11, and BBI608 led to effectively inducing of apoptosis, cell cycle arrest, and apoptotic genes expression level and significantly reduce of colony-forming, migration, and anti-apoptotic genes expression rate. Importantly, the maximum anticancer effect against CT26 cell line was seen upon combination ReoT3D, CPT-11, and BBI608 treatment.

CONCLUSION

The present study highlights that combination of ReoT3D, CPT-11, and BBI560 showed synergistic anticancer activity against CT26 cell line. This modality might be considered as a new approach against colorectal cancer (CRC) in the in vivo and clinical trial investigations.

In Vitro Anti-cancer Activity of Adipose-Derived Mesenchymal Stem Cells Increased after Infection with Oncolytic Reovirus

Purpose: Reovirus type 3 Dearing (ReoT3D), a wild type oncolytic virus (OV) from the Reoviridae family, kills KRAS mutant cancer cells. However, the use of OVs has faced with some limitations such as immune responses, and delivery of OVs to the tumor sites in systemic therapy. To solve this, and also to increase the anti-cancer effects of these OVs, mesenchymal stem cells (MSCs) might be used as an effective vehicle for OVs delivery. In this study, we examined the anti-cancer effects of human adipose derived-MSCs (AD-MSCs) as a vehicle of ReoT3D against human glioblastoma cells.

Methods: Here, AD-MSCs were characterized and toxicity of ReoT3D on them was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Then, capability of AD-MSCs for virus production was assessed by real-time polymerase chain reaction (PCR), and different in vitro anti-cancer experiments were applied for our anti-cancer purposes.

Results: Our results from toxicity assay revealed that the isolated and provoked AD-MSCs were resistant to nontoxic concentration multiplicity of infection (MOI) >1 pfu/cells of ReoT3D. In addition, the results indicated that AD-MSCs were susceptible for virus life cycle complementation and were capable for production of virus progenies. Furthermore, our results showed that AD-MSCs had oncolysis effects and increased the anti-cancer effects of ReoT3D.

Conclusion: AD-MSCs as a susceptible host for oncolytic reovirus could increase the anti-cancer activity of this OV against glioblastoma multiforme (GBM) cell line.

Recent advances of oncolytic virus in cancer therapy

Oncolytic viruses have been taking the front stage in biological therapy for cancer recently. The first and most potent virus to be used in oncolytic virotherapy is human adenovirus. Recently, ongoing extensive research has suggested that other viruses like herpes simplex virus (HSV) and measles virus can also be considered as potential candidates in cancer therapy. An HSV-based oncolytic virus, T-VEC, has completed phase Ш clinical trial and has been approved by the U.S. Food and Drug Administration (FDA) for use in biological cancer therapy. Moreover, the vaccine strain of the measles virus has shown impressive results in pre-clinical and clinical trials. Considering their therapeutic efficacy, safety, and reduced side effects, the use of such engineered viruses in biological cancer therapy has the potential to establish a milestone in cancer research. In this review, we summarize the recent clinical advances in the use of oncolytic viruses in biological therapy for cancer. Additionally, this review evaluates the potential viral candidates for their benefits and shortcomings and sheds light on the future prospects.

Targeting XIST induced apoptosis of human osteosarcoma cells by activation of NF-kB/PUMA signal

The long noncoding RNA X-inactive specific transcript (XIST) plays vital roles in tumor progression. However, the underlying mechanisms remain unclear. This study investigated the effects and mechanisms of targeting XIST on osteosarcoma (OS) cells in vitro and in vivo. We used shRNA to knockdown XIST to evaluate cell growth and apoptosis in U2OS cells in vitro and xenograft formation in vivo. An observed relationship between XIST and the p53 upregulated modulator of apoptosis (PUMA) and nuclear factor-kappa B (NF-kB) pathway was further explored by using small interfering RNA (siRNA). Our results showed that suppression of XIST by short hairpin RNA (shRNA) impeded U2OS cell growth, induced apoptosis and lessened OS xenograft tumor growth. Targeting XIST increased NF-kB-dependent PUMA upregulation in U2OS cells. Upregulation of PUMA is correlated with suppression of XIST-induced apoptosis in U2OS cells. Therefore, inhibition of XIST could promote U2OS cell death via activation of NF-kB/PUMA pathways.

Astragaloside IV regulates NF-κB-mediated cellular senescence and apoptosis of hepatic stellate cells to suppress PDGF-BB-induced activation

Activated hepatic stellate cells (HSCs) are the principal effectors during hepatic fibrosis, which is characterized by the accumulation of extracellular matrix. Therefore, present therapies and investigations into hepatic fibrosis mainly focus on the suppression of activated HSCs. Astragaloside IV (ASIV) is an effective constituent extracted from the plant Astragalus membranaceus and has exhibited anti-fibrotic properties in hepatic fibrosis. However, its protective mechanism against hepatic fibrosis is not fully understood. The present study aimed to investigate the mechanistic role of ASIV on rat HSC-T6 cells activated with platelet-derived growth factor (PDGF)-BB. HSC-T6 cells were activated using PDGF-BB and subsequently treated with ASIV (final concentrations of 20 and 40 µg/ml) for 48 h. ASIV treatment decreased the expression of α1 type I collagen, α-smooth muscle actin and fibronectin on mRNA and protein levels, suggesting that ASIV suppresses PDGF-BB-induced HSC-T6 activation. Senescence-associated β-galactosidase activity, p21, high-mobility group AT-hook 1 and p53, common biomarkers of senescence, were upregulated by ASIV treatment. In addition, the expression of telomerase reverse transcriptase was reduced. ASIV promoted apoptosis of PDGF-BB-activated HSC-T6 cells. The NF-κB signaling pathway, which controls cellular senescence and apoptosis, was demonstrated to be stimulated by ASIV by increasing p65, p52, p50 and inhibitor of NF-κB kinase α expression levels, and by suppressing the expression of NF-κB inhibitor α. Taken together, these results demonstrated that ASIV promoted cellular senescence and apoptosis by activating the NF-κB pathway to suppress PDGF-BB-induced HSC-T6 activation; with potential implications for the treatment of hepatic fibrosis.

MiR-16-5p inhibits breast cancer by reducing AKT3 to restrain NF-κB pathway

Background: Breast cancer endangers the life of women and has become the major cause of deaths among them. MiRNAs are found to exert a regulatory effect on the migration, proliferation and apoptosis of breast cancer cells. This research aims at investigating the miR-16-5p expression and its effect on the pathogenesis of breast cancer. Methods: Their clinical data were analyzed with qRT-PCR. CCK8, EdU and Transwell was performed to explore the function of miR-16-5p in cell migration and proliferation of breast cancer cells. Dual-luciferase reporter assay, immunohistochemistry and Western blotting were carried out to explore the relation between miR-16-5p and AKT3. Results: It was discovered that miR-16-5p was lowly expressed in breast cancer patients. Meanwhile, breast cancer patients with under-expressed miR-16-5p had a lower survival rate than those with highly expressed miR-16-5p. Furthermore, decreased miR-16-5p in cell and animal models enhanced migration and proliferation of breast cancer cells, stimulated cell cycle and reduced cell apoptosis. Finally, we found miR-16-5p restrained the NF-κB pathway and decreased AKT3 gene, thereby suppressing the breast cancer development. Conclusion: It can be seen that miR-16-5p exhibits a low expression in breast cancer tissues, which can inhibit breast cancer by restraining the NF-κB pathway and elevating reducing AKT3.

The oncolytic efficacy and safety of avian reovirus and its dynamic distribution in infected mice

Primary liver cancer is a major public health challenge that ranks as the third most common cause of cancer worldwide despite therapeutic improvement. Reovirus has been emerging as a potential anti-cancer agent and is undergoing multiple clinical trials, and it is reported that reovirus can preferentially cause the cell death of a variety of cancers in a manner of apoptosis. As few studies have reported the efficacy of oncolytic activity and safety profile of avian reovirus, in our study, LDH assay, MTT assay, DAPI staining, and flow cytometry assay were performed to demonstrate the oncolytic effects of avian reovirus against the HepG2 cells, and quantitative real-time PCR (qRT-PCR) and animal experiments were conducted to investigate the dynamic distribution of avian reovirus in infected mice and then illustrate the safety and tissue tropism of avian reovirus. LDH assay, DAPI staining, and flow cytometry assay confirmed the efficacy of the oncotherapeutic effects of avian reovirus, and MTT assay has indicated that avian reovirus suppressed the proliferation of HepG2 cells and decreased their viability significantly. qRT-PCR revealed the dynamic distribution of avian reovirus in infected mice that avian reovirus might replicate better and have more powerful oncolytic activity in liver, kidney, and spleen tissues. Furthermore, histopathological examination clearly supported that avian reovirus appeared non-pathogenic to the normal host, so our study may provide the new insights and rationale for the new strategy of removing liver cancer.

Impact statement

We demonstrated the efficacy of oncolytic activity of avian reovirus (ARV) by LDH assay, MTT assay, DAPI staining, and flow cytometry assay, and also investigated the dynamic distribution of ARV in infected mice and then illustrated the safety and tissue tropism of ARV by quantitative real-time PCR (qRT-PCR) and animal experiments. Collectively, our study may provide the new insights and rationale for the new strategy of removing liver cancer.

Novel insights into the evolution of the caveolin superfamily and mechanisms of antiapoptotic effects and cell proliferation in lamprey

Caveolin-1 is the main structural and functional component of caveolin, and it is involved in the regulation of cholesterol transport, endocytosis, and signal transduction. Moreover, changes in caveolin-1 play an important role in tumorigenesis and inflammatory processes. Previous studies have demonstrated that human caveolin-1 is mainly located in the cell membrane and exhibits cell type- and stage-dependent functional differences during cancer development and inflammatory responses. However, the role of Lamprey-caveolin-like (L-caveolin-like) in lamprey remained unknown. Here, we demonstrated that L-caveolin-like performs anti-inflammation and oncogenic functions and the function of caveolin-1 diverged during vertebrate evolution. Moreover, the results reveal the mechanism underlying the antiapoptotic effects of L-caveolin-like. An L-caveolin-like gene from Lampetra japonica (L. japonica) was identified and characterized. L-Caveolin-like was primarily distributed in the leukocytes, intestines and supraneural bodies (Sp-bodies) immune organs as indicated by Q-PCR and immunohistochemistry assays. The mRNA and protein expression levels of L-caveolin exhibited consistent increases in expression at 2 and 72 h in adult tissues after exposure to lipopolysaccharide (LPS) and in leukocytes stimulated by Vibrio anguillarum (V. anguillarum), Staphylococcus aureus (S. aureus), and Poly I:C. Furthermore, the overexpression of pEGFP-N1-L-caveolin-like was associated with a distinct localization in mitochondria, with decreased cytochrome C (Cyt C) and mitochondrial Cyt C oxidase subunit I (CO I) expression. In addition, increased cellular ATP levels suggested that this protein prevented mitochondrial damage. The overexpression of pEGFP-N1-L-caveolin-like led to the altered expression of factors related to apoptosis, such as decreased Caspase-9, Caspase-3, p53, and Bax expression and increased Bcl-2 expression. In addition, the overexpression of pEGFP-N1-L-caveolin-like promoted cell proliferation associated with upregulated EGF, bFGF, and PDGFB expression. Together, these findings indicated that the L-caveolin-like protein from L. japonica induced the activation of antiapoptotic effects via the mitochondrial Cyt C-mediated Caspase-3 signaling pathway. Our analysis further suggests that L-caveolin-like is an oncogene protein product and anti-inflammatory molecule from lamprey that evolved early in vertebrate evolution.

Crosstalk Between Connexin32 and Mitochondrial Apoptotic Signaling Pathway Plays a Pivotal Role in Renal Ischemia Reperfusion-Induced Acute Kidney Injury

Aims: Perioperative acute kidney injury (AKI) resulting from renal ischemia reperfusion (IR) is not conducive to the postoperative surgical recovery. Our previous study demonstrated that reactive oxygen species (ROS) transmitted by gap junction (GJ) composed of connexin32 (Cx32) contributed to AKI. However, the precise underlying pathophysiologic mechanisms were largely unknown. This study focuses on the underlying mechanisms related to ROS transmitted by Cx32 responsible for AKI aggravation. Results: In a set of in vivo studies, renal IR was found to cause severe impairment in renal tissues with massive ROS generation, which occurred contemporaneously with activation of NF-κB/p53/p53 upregulated modulator of apoptosis (PUMA)-mediated mitochondrial apoptosis pathways. Cx32 deficiency alleviated renal IR-induced AKI, and simultaneously attenuated ROS generation and distribution in renal tissues, which further inhibited NF-κB/p53/PUMA-mediated mitochondrial apoptotic pathways. Correspondingly, in a set of in vitro studies, hypoxia reoxygenation (HR)-induced cellular injury, and cell apoptosis in both human kidney tubular epithelial cells (HK-2s) and rat kidney tubular epithelial cells (NRK52Es) were significantly attenuated by Cx32 inhibitors or Cx32 gene knockdown. More importantly, Cx32 inhibition not only decreased ROS generation and distribution in human or rat kidney tubular epithelial cells but also inhibited its downstream NF-κB/p53/PUMA-mediated mitochondrial apoptotic pathway activation. Innovation and Conclusion: This is the first identification of the underlying mechanisms of IR-induced renal injury integrally which demonstrates the critical role played by Cx32 in IR-induced AKI. Moreover, GJ composed of Cx32 manipulates ROS generation and distribution between neighboring cells, and alters activation of NF-κB/p53/PUMA-mediated mitochondrial apoptotic pathways. Both inhibiting Cx32 function and scavenging ROS effectively reduce mitochondrial apoptosis and subsequently attenuate AKI, providing effective strategies for kidney protection.

NF-κB Signaling in Targeting Tumor Cells by Oncolytic Viruses-Therapeutic Perspectives

In recent years, oncolytic virotherapy became a promising therapeutic approach, leading to the introduction of a novel generation of anticancer drugs. However, despite evoking an antitumor response, introducing an oncolytic virus (OV) to the patient is still inefficient to overcome both tumor protective mechanisms and the limitation of viral replication by the host. In cancer treatment, nuclear factor (NF)-κB has been extensively studied among important therapeutic targets. The pleiotropic nature of NF-κB transcription factor includes its involvement in immunity and tumorigenesis. Therefore, in many types of cancer, aberrant activation of NF-κB can be observed. At the same time, the activity of NF-κB can be modified by OVs, which trigger an immune response and modulate NF-κB signaling. Due to the limitation of a monotherapy exploiting OVs only, the antitumor effect can be enhanced by combining OV with NF-κB-modulating drugs. This review describes the influence of OVs on NF-κB activation in tumor cells showing NF-κB signaling as an important aspect, which should be taken into consideration when targeting tumor cells by OVs.

Current understanding of reovirus oncolysis mechanisms

Mammalian orthoreovirus (reovirus) is under development as a cancer virotherapy. Clinical trials demonstrate that reovirus-based therapies are safe and tolerated in patients with a wide variety of cancers. Although reovirus monotherapy has proven largely ineffective, reovirus sensitizes cancer cells to existing chemotherapeutic agents and radiation. Clinical trials are underway to test the efficacy of reovirus in combination with chemotherapeutic and radiation regimens and to evaluate the effectiveness of reovirus in conjunction with immunotherapies. Central to the use of reovirus to treat cancer is its capacity to directly kill cancer cells and alter the cellular environment to augment other therapies. Apoptotic cell death is a prominent mechanism of reovirus cancer cell killing. However, reoviruses can also kill cancer cells through nonapoptotic mechanisms. Here, we describe mechanisms of reovirus cancer cell killing, highlight how reovirus is used in combination with existing cancer treatments, and discuss what is known as to how reovirus modulates cancer immunotherapy.

Importin-β and exportin-5 are strong biomarkers of productive reoviral infection of cancer cells

Acute reoviral infection has been extensively studied given the virus's propensity to target malignant cells and activate caspase-3 mediated apoptosis. Reovirus infection of malignant N1E-115 mouse neuroblastoma cells led to significant increased expression of importin-β and exportin-5 mRNAs (qRTPCR) and proteins (immunohistochemistry) which was partially blocked by small interfering LNA oligomers directed against the reoviral genome. Co-expression analysis showed that the N1E-115 cells that contained reoviral capsid protein had accumulated importin-β and exportin-5, as well as activated caspase 3. Reoviral oncolysis using a syngeneic mouse model of multiple myeloma similarly induced a significant increase in importin-β and exportin-5 proteins that were co-expressed with reoviral capsid protein and caspase-3. Apoptotic proteins (BAD, BIM, PUMA, NOXA, BAK, BAX) were increased with infection and co-localized with reoviral capsid protein. Surprisingly the anti-apoptotic MCL1 and bcl2 were also increased and co-localized with the capsid protein suggesting that it was the balance of pro-apoptotic molecules that correlated with activation of caspase-3. In summary, productive reoviral infection is strongly correlated with elevated importin-β and exportin-5 levels which may serve as biomarkers of the disease in clinical specimens.

Importin-β and exportin-5 are indicators of acute viral infection: Correlation of their detection with commercially available detection kits

This work focused on immunohistochemistry markers of acute viral infections. Viral infected cells were detected by in situ based methods (reovirus, rabies virus) or cytologic changes (human papillomavirus, molloscum contagiosum virus, herpes simplex virus). Two proteins involved in nuclear trafficking, importin-β and exportin-5, were detected in the infected cells for each virus and not in the control tissues. A wide variety of other proteins, including caspase-3, and bcl-2 family members (bcl2, bclX, MCL1, BAK, BAX, BIM, BAD) showed wide variations in expression among the different viral infections. Specificity of the importin-β and exportin-5 signals varied greatly with different commercially available peroxidase conjugates. It is concluded that immunohistochemistry detection of importin-β and exportin-5 may be useful markers of acute viral infection, which suggests that increased nuclear trafficking may be an important concomitant of viral proliferation.

Hsp27 reduces cold ischemia-reperfusion injury in heart transplantation through regulation of NF-κB and PUMA signaling

BACKGROUND AND OBJECTIVE

Global myocardial ischemia-reperfusion (I/R) injury after heart transplantation is believed to impair graft function and aggravate episodes of both acute and chronic rejection. The 27-kDa heat shock protein (Hsp27) has a potent ability to alleviate I/R after cardiac transplantation. The aim of this study was to investigate the anti-I/R injury effect of Hsp27 to elucidate the underling mechanisms.

METHODS

Heart grafts from BALB/c mice were preserved in University of Wisconsin (UW) solution (control) or UW solution containing pAAV-Hsp27 (Hsp27 solution) at 4°C for 48 h and subsequently transplanted into syngeneic recipients for 72 h. The heart grafts were then collected for histopathological and gene expression analyses. An in vitro I/R model (H9c2 cells or H9c2/Hsp27 cells) was constructed. Then, protein and mRNA expression of Hsp27, p65, p53 upregulated modulator of apoptosis (PUMA), interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in heart tissues and H9c2 cells were detected with western blot and reverse transcription polymerase chain reaction analyses. Caspase-3 activity was detected using a commercial assay, while protein levels of IL-6, IL-1β, and TNF-α were detected using specific enzyme-linked immunosorbent assays. NF-κB activity was detected with an electrophoretic mobility shift assay. Cell apoptosis was detected with the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and flow cytometric analysis.

RESULTS

Cold I/R caused severe morphologic myocardial injury of heart grafts from wild type C57BL/c mice, whereas grafts from Hsp27 preservation showed less damage as demonstrated by decreased cell apoptosis/death and the preservation of the normal structure of the heart. Hsp27 inhibited I/R-induced injury as indicated by the reduction in cardiac troponin I activities and decreased cardiac tissue levels of the proinflammatory factors TNF-α, IL-1β, and IL-6. Hsp27 was further demonstrated to significantly inhibit nuclear translocation of p65 and p53 upregulated modulator of apoptosis (PUMA) expression.

CONCLUSIONS

These results suggested that the cardioprotective effect of Hsp27 could be due to the suppression of the myocardial inflammatory response and apoptosis by blocking the NF-κB-dependent pro-inflammatory and NF-κB-dependent PUMA signaling pathways.