Efficient inhibition of intraperitoneal human ovarian cancer growth and prolonged survival by gene transfer of vesicular stomatitis virus matrix protein in nude mice

Matrix Protein of Vesicular Stomatitis Virus Targets the Mitochondria, Reprograms Glucose Metabolism, and Sensitizes to 2-Deoxyglucose in Glioblastoma

A potential therapeutic approach for cancer treatment is target oxidative phosphorylation and glycolysis simultaneously. The matrix protein of vesicular stomatitis virus (VSV MP) can target the surface of mitochondria, causing morphological changes that may be associated with mitochondrial dysfunction and oxidative phosphorylation inhibition. Previous research has shown that mitochondrial abnormalities can direct glucose metabolism toward glycolysis. Thus, after treatment with VSV MP, glycolysis inhibition is necessary to completely block glucose metabolism and eradicate cancer. Here, to inhibit glycolysis, the 2-deoxy-D-glucose (2-DG), a synthetic glucose analog was used to combine with VSV MP to treat cancer. This study aims to determine how VSV MP affects the glucose bioenergetic metabolism of cancer cells and to evaluate the synergistic effect of 2-DG when combined with VSV. Our results indicated that in U87 and C6 glioblastoma cell lines, VSV MP caused mitochondrial membrane potential loss, cytochrome c release, and glucose bioenergetics metabolism reprogramming. When combined with 2-DG, VSV MP synergistically aggravated cell viability, apoptosis, and G2/M phase arrest. Meanwhile, the combination therapy exacerbated ATP depletion, activated AMPK, and inhibited mammalian target of rapamycin signaling pathways. In addition, 2-DG treatment alone induced autophagy in glioblastoma cells; however, VSV MP inhibited the autophagy induced by 2-DG in combined treatment and finally contributed to the enhanced cytotoxic effect of the combination strategy in U87 and C6 cancer cells. In the orthotopic U87 glioblastoma model and subcutaneous C6 glioblastoma model, the combined treatment led to significant tumor regression and prolonged survival. A potent therapeutic approach for treating glioblastoma may be found in the combination of VSV MP and glycolytic inhibitors.

Viral Vectors in Gene Therapy: Where Do We Stand in 2023?

Viral vectors have been used for a broad spectrum of gene therapy for both acute and chronic diseases. In the context of cancer gene therapy, viral vectors expressing anti-tumor, toxic, suicide and immunostimulatory genes, such as cytokines and chemokines, have been applied. Oncolytic viruses, which specifically replicate in and kill tumor cells, have provided tumor eradication, and even cure of cancers in animal models. In a broader meaning, vaccine development against infectious diseases and various cancers has been considered as a type of gene therapy. Especially in the case of COVID-19 vaccines, adenovirus-based vaccines such as ChAdOx1 nCoV-19 and Ad26.COV2.S have demonstrated excellent safety and vaccine efficacy in clinical trials, leading to Emergency Use Authorization in many countries. Viral vectors have shown great promise in the treatment of chronic diseases such as severe combined immunodeficiency (SCID), muscular dystrophy, hemophilia, β-thalassemia, and sickle cell disease (SCD). Proof-of-concept has been established in preclinical studies in various animal models. Clinical gene therapy trials have confirmed good safety, tolerability, and therapeutic efficacy. Viral-based drugs have been approved for cancer, hematological, metabolic, neurological, and ophthalmological diseases as well as for vaccines. For example, the adenovirus-based drug Gendicine® for non-small-cell lung cancer, the reovirus-based drug Reolysin® for ovarian cancer, the oncolytic HSV T-VEC for melanoma, lentivirus-based treatment of ADA-SCID disease, and the rhabdovirus-based vaccine Ervebo against Ebola virus disease have been approved for human use.

Nanoparticle-Based Combination Therapy for Ovarian Cancer

Ovarian cancer is one of the most common malignant tumors in gynecology with a high incidence. Combination therapy, eg, administration of paclitaxel followed by a platinum anticancer drug is recommended to treat ovarian cancer due to its advantages in, eg, reducing side effects and reversing (multi)drug-resistance compared to single treatment. However, the benefits of combination therapy are often compromised. In chemo and chemo/gene combinations, co-deposition of the combined therapeutics in the tumor cells is required, which is difficult to achieve due to dramatic pharmacokinetic differences between combinational agents in free forms. Moreover, some undesired properties such as the low-water solubility of chemodrugs and the difficulty of cellular internalization of gene therapeutics also hinder the therapeutic potential. Delivery of dual or multiple agents by nanoparticles provides opportunities to tackle these limits. Nanoparticles encapsulate hydrophobic drug(s) to yield aqueous dispersions facilitating its administration and/or to accommodate hydrophilic genes facilitating its access to cells. Moreover, nanoparticle-based therapeutics can not only improve drug properties (eg, in vivo stability) and ensure the same drug disposition behavior with controlled drug ratios but also can minimize drug exposure of the normal tissues and increase drug co-accumulation at targeted tissues via passive and/or active targeting strategies. Herein, this work summarizes nanoparticle-based combination therapies, mainly including anticancer drug-based combinations and chemo/gene combinations, and emphasizes the advantageous outcomes of nanocarriers in the combination treatment of ovarian cancer. In addition, we also review mechanisms of synergetic effects resulting from different combinations.

Therapeutic Applications for Oncolytic Self-Replicating RNA Viruses

Self-replicating RNA viruses have become attractive delivery vehicles for therapeutic applications. They are easy to handle, can be rapidly produced in large quantities, and can be delivered as recombinant viral particles, naked or nanoparticle-encapsulated RNA, or plasmid DNA-based vectors. The self-replication of RNA in infected host cells provides the means for generating much higher transgene expression levels and the possibility to apply substantially reduced amounts of RNA to achieve similar expression levels or immune responses compared to conventional synthetic mRNA. Alphaviruses and flaviviruses, possessing a single-stranded RNA genome of positive polarity, as well as measles viruses and rhabdoviruses with a negative-stranded RNA genome, have frequently been utilized for therapeutic applications. Both naturally and engineered oncolytic self-replicating RNA viruses providing specific replication in tumor cells have been evaluated for cancer therapy. Therapeutic efficacy has been demonstrated in animal models. Furthermore, the safe application of oncolytic viruses has been confirmed in clinical trials. Multiple myeloma patients treated with an oncolytic measles virus (MV-NIS) resulted in increased T-cell responses against the measles virus and several tumor-associated antigen responses and complete remission in one patient. Furthermore, MV-CEA administration to patients with ovarian cancer resulted in a stable disease and more than doubled the median overall survival.

Self-replicating vehicles based on negative strand RNA viruses

Self-replicating RNA viruses have been engineered as efficient expression vectors for vaccine development for infectious diseases and cancers. Moreover, self-replicating RNA viral vectors, particularly oncolytic viruses, have been applied for cancer therapy and immunotherapy. Among negative strand RNA viruses, measles viruses and rhabdoviruses have been frequently applied for vaccine development against viruses such as Chikungunya virus, Lassa virus, Ebola virus, influenza virus, HIV, Zika virus, and coronaviruses. Immunization of rodents and primates has elicited strong neutralizing antibody responses and provided protection against lethal challenges with pathogenic viruses. Several clinical trials have been conducted. Ervebo, a vaccine based on a vesicular stomatitis virus (VSV) vector has been approved for immunization of humans against Ebola virus. Different types of cancers such as brain, breast, cervical, lung, leukemia/lymphoma, ovarian, prostate, pancreatic, and melanoma, have been the targets for cancer vaccine development, cancer gene therapy, and cancer immunotherapy. Administration of measles virus and VSV vectors have demonstrated immune responses, tumor regression, and tumor eradication in various animal models. A limited number of clinical trials have shown well-tolerated treatment, good safety profiles, and dose-dependent activity in cancer patients.

A Vesicular Stomatitis Virus-Inspired DNA Nanocomplex for Ovarian Cancer Therapy

Gene therapy provides a novel method for cancer therapy. This study shows a DNA nanocomplex that is inspired from vesicular stomatitis virus (VSV) for ovarian cancer therapy. This DNA nanocomplex consists of a cationized monomethoxy poly (ethylene glycol)-poly (d,l-lactide) (MPEG-PLA) nanoparticle and a plasmid encoding the matrix protein of vesicular stomatitis virus (VSVMP) that plays a critical role in the VSV-induced apoptosis of cancer cells. The cationized MPEG-PLA nanoparticle that is self-assembled by MPEG-PLA copolymer and N -[1-(2,3-dioleoyloxy) propyl]-N,N,N-trimethylammonium chloride (DOTAP) has low cytotoxicity and high transfection efficiency (>80%). Intraperitoneal administration of the p VSVMP nanocomplex remarkably inhibits the intraperitoneal metastasis of ovarian cancer and does not cause significant systemic toxicity. The apoptosis induction and anti-angiogenesis are involved in the anticancer mechanism. This work demonstrates a VSV-inspired DNA nanocomplex that has potential application for the treatment of intraperitoneal metastasis of ovarian cancer.

A 3D-Engineered Conformal Implant Releases DNA Nanocomplexs for Eradicating the Postsurgery Residual Glioblastoma

Gene therapy has great promise for glioblastoma treatment; however, it remains a great challenge to efficiently deliver genes to the brain. The incomplete resection of glioblastoma always leads to poor prognosis. Here, a 3D‐engineered conformal implant for eradicating the postsurgery residual glioblastoma is designed. This implant is constructed by 3D‐printing technology to match the tumor cavity and release an oncolytic virus‐inspired DNA nanocomplex to kill glioblastoma cells through apoptosis induction. Meanwhile, a 3D‐engineered subcutaneous glioblastoma xenograft is built to mimic the resection tumor cavity in mice. Insertion of the implant into the glioblastoma resection cavity efficiently delays tumor recurrence and significantly prolongs overall survival. This study provides a proof‐of‐concept of glioblastoma therapy using a conformal implant that releases oncolytic DNA nanocomplexs. This strategy can lead to the development of future precision therapy for eradicating postsurgery residual tumors.

Nanoparticles co-delivering pVSVMP and pIL12 for synergistic gene therapy of colon cancer

Nanoparticles delivering therapeutic genes have promising applications in cancer treatments.

VEGF-D-enhanced lymph node metastasis of ovarian cancer is reversed by vesicular stomatitis virus matrix protein

Lymphatic metastasis is a poor prognostic factor in ovarian cancer, which correlates to the majority of cancer deaths. Matrix protein (MP) of vesicular stomatitis virus (VSV) exhibits potent antitumor and antiangiogenic activities through inducing apoptosis and inhibiting angiogenesis. In this study, the antitumor and antimetastatic effects of MP were further investigated. Wild-type SKOV3 (WT-SK) cells were successfully transfected with empty vector pcDNA3.1 plasmid, or pcDNA3.1-VEGF-D recombinant plasmid to construct cell lines named EV-SK, and VEGFD-SK, respectively. Inhibition of VEGFD-SK cell migration and invasion was detected by Transwell and wound healing assay. Then, lymphogenous metastatic model of ovarian cancer was established by injecting VEGFD-SK cells subcutaneously into the left hindlimb claw pad of nude mice. The inducted apoptotic effect of MP on VEGFD-SK cells were assessed by flow analysis and Hoechst-33258 staining, respectively, in vitro. The in vivo antitumor and antiangiogenic activities of MP gene were evaluated with lymphogenous metastatic model of ovarian cancer. Tumor volume and lymphatic metastasis rates were measured. Lymphatic vessels were delineated using Evan's blue and LYVE-1 staining. Expression of VEGF-D and MMP-2 were evaluated by immunostaining. Apoptosis of tumor cells was analyzed by Hoechst-33258 staining. Mice bearing VEGFD-SK tumor cells displayed more rapid tumorigenesis, higher lymphogenous metastatic tendency and increased lymphatic vessel density compared with the mice bearing WT-SK or EV-SK cells. However, VEGF-D-enhanced metastasis was evidently reversed by MP. MP significantly reduced the invasion of VEGFD-SK cells, tumor volume, lymphatic metastasis rates and lymphatic vessel density compared with control groups (P<0.05), accompanied with down-expression of VEGF-D and MMP-2 and increased apoptosis. Our data indicate that MP has strong antitumor and antimetastatic abilities, and it may be a promising therapeutic strategy against the lymphatic metastasis of human ovarian cancer.

Ovarian cancer treatment with a tumor-targeting and gene expression-controllable lipoplex

Overexpression of folate receptor alpha (FRα) and high telomerase activity are considered to be the characteristics of ovarian cancers. In this study, we developed FRα-targeted lipoplexes loaded with an hTERT promoter-regulated plasmid that encodes a matrix protein (MP) of the vesicular stomatitis virus, F-LP/pMP_(2.5), for application in ovarian cancer treatment. We first characterized the pharmaceutical properties of F-LP/pMP_(2.5). The efficient expression of the MP-driven hTERT promoter in SKOV-3 cells was determined after an in-vitro transfection assay, which was significantly increased compared with a non-modified LP/pMP_(2.5) group. F-LP/pMP_(2.5) treatment significantly inhibited the growth of tumors and extended the survival of mice in a SKOV-3 tumor model compared with other groups. Such an anti-tumor effect was due to the increased expression of MP in tumor tissue, which led to the induction of tumor cell apoptosis, inhibition of tumor cell proliferation and suppression of tumor angiogenesis. Furthermore, a preliminary safety evaluation demonstrated a good safety profile of F-LP/pMP_(2.5) as a gene therapy agent. Therefore, FRα-targeted lipoplexes with therapeutic gene expression regulated by an hTERT promoter might be a promising gene therapy agent and a potential translational candidate for the clinical treatment of ovarian cancer.

Livin modulates the apoptotic effects of vesicular stomatotitis virus in lung adenocarcinoma

Vesicular stomatitis virus (VSV) has shown promise in cancer treatment. However, it achieved limited effects against lung cancer. Lung cancer has intrinsic mechanisms that render resistance to VSV. In this study, we attempted to explore the expression of the anti-apoptotic factor Livin in lung adenocarcinoma and its possible relationship to VSV vulnerability. We found VSV induced apoptosis in a time- and dose-dependent manner, with the concomitant change in the expression of Livin. We elevated the expression of Livin both transiently and stably, and the cells became insensitive to VSV treatment. We further found the BIR domain of Livin was mainly responsible for its modulation effects. This finding suggested a possible interaction with the second mitochondria-derived activator of caspase (SMAC). The knock-down of SMAC also inhibited apoptosis by VSV. The relationship was confirmed by the co-immunoprecipitation. Finally, we knocked down the endogenous Livin, and the knock-down sensitized cells to VSV treatment. Our results suggested the important role of Livin and its partner molecule in the process of VSV treatment.

Inhibition of lymphatic metastases by a survivin dominant-negative mutant

Metastasis is the most lethal attribute of human malignancy. High-level expression of survivin is involved in both carcinogenesis and angiogenesis in cancer. Previous studies indicate that a mutation of the threonine residue at position 34 (Thr34Ala) of survivin generates a dominant-negative mutant that induces apoptosis, inhibits angiogenesis, and suppresses highly metastatic breast carcinoma in mouse models. We investigated the efficacy of gene therapy with a survivin dominant-negative mutant and possible factors related to lymph node metastasis. The metastasis rate was compared between each group in order to find a survivin-targeted therapy against lymphangiogenesis in its earliest stages. We established lymph node metastasis models and treated animals with H22 tumors with Lip-mSurvivinT34A (Lip-mS), Lip-plasmid (Lip-P), or normal saline (NS). Eight days after the last dose, five randomly chosen mice from each group were sacrificed. We detected the apoptotic index, microvessel density (MVD), lymphatic microvessel density (LMVD), and the expression of VEGF-D with immunohistochemistry. After the remaining animals were sacrificed, we compared the tumor-infiltrated lymph nodes in each group. Administration of mSurvivinT34A plasmid complexed with cationic liposome (DOTAP/chol) resulted in the efficacious inhibition of tumor growth and lymph node metastasis within the mouse H22 tumor model. These responses were associated with tumor cell apoptosis, and angiogenesis and lymphangiogenesis inhibition. Our results suggested that Lip-mSurvivinT34A induced apoptosis and inhibited tumor angiogenesis and lymphangiogenesis, thus suppressing tumor growth and lymphatic metastasis. The mSurvivinT34A survivin mutant is a promising strategy of gene therapy to inhibit lymphatic metastasis.

Oncolytic myxoma virus: the path to clinic

Many common neoplasms are still noncurative with current standards of cancer therapy. More therapeutic modalities need to be developed to significantly prolong the lives of patients and eventually cure a wider spectrum of cancers. Oncolytic virotherapy is one of the promising new additions to clinical cancer therapeutics. Successful oncolytic virotherapy in the clinic will be those strategies that best combine tumor cell oncolysis with enhanced immune responses against tumor antigens. The current candidate oncolytic viruses all share the common property that they are relatively nonpathogenic to humans, yet they have the ability to replicate selectively in human cancer cells and induce cancer regression by direct oncolysis and/or induction of improved anti-tumor immune responses. Many candidate oncolytic viruses are in various stages of clinical and preclinical development. One such preclinical candidate is myxoma virus (MYXV), a member of the Poxviridae family that, in its natural setting, exhibits a very restricted host range and is only pathogenic to European rabbits. Despite its narrow host range in nature, MYXV has been shown to productively infect various classes of human cancer cells. Several preclinical in vivo modeling studies have demonstrated that MYXV is an attractive and safe candidate oncolytic virus, and hence, MYXV is currently being developed as a potential therapeutic for several cancers, such as pancreatic cancer, glioblastoma, ovarian cancer, melanoma, and hematologic malignancies. This review highlights the preclinical cancer models that have shown the most promise for translation of MYXV into human clinical trials.

Administration of PLGA nanoparticles carrying shRNA against focal adhesion kinase and CD44 results in enhanced antitumor effects against ovarian cancer

The two membrane-bound proteins, focal adhesion kinase (FAK) and CD44, are involved in processes critical to cancer progression. FAK has an active role in angiogenesis, cell proliferation and cell apoptosis, whereas the heavily glycosylated CD44 has been implicated in cancer metastasis. Here, using short hairpin RNA (shRNA) against FAK and CD44, we demonstrate that simultaneous knockdown of both these genes inhibits cancer growth more efficiently than knockdown of either gene individually. Plasmids targeting these genes or non-relative control sequences were constructed and delivered to ovarian cancer targets by biodegradable poly D,L-lactide-co-glycolide acid nanoparticles (PLGANPs). Nude mice were utilized in an intraperitoneal model of ovarian carcinomatosis to assess antitumor efficacy in vivo. Single gene knockdown resulted in significantly smaller tumors than those observed in the empty-vector control (P's<0.001). More importantly, knockdown of both genes resulted in tumors smaller than both the empty-vector group (P<0.0001) and the single gene knockdown groups (P's<0.001). Knockdown of both FAK and CD44 resulted in tumors with inhibited angiogenesis, reduced proliferation and increased apoptosis as compared with controls (P's<0.001) and single knockdown groups (P's<0.05). These results indicate that dual knockdown of FAK and CD44 in the tumors of patients with ovarian cancer may have an enhanced therapeutic effect, and point toward a mechanism involving the inhibition of angiogenesis, cellular proliferation and the induction of apoptosis.

Matrix protein of vesicular stomatitis virus: a potent inhibitor of vascular endothelial growth factor and malignant ascites formation

Malignant ascites is common in various types of cancers and is difficult to manage. Vascular endothelial growth factor (VEGF) has a pivotal role in malignant ascites. The matrix protein of vesicular stomatitis virus (VSVMP) has been shown to inhibit host gene expression and induce the apoptosis of cancer cells. The present study was designed to determine whether VSVMP suppresses the formation of ascites in ascites-producing peritoneal carcinomatosis. BALB/c female mice, 6-8 weeks old, bearing peritoneal tumors of H22 or MethA cells received an intraperitoneal administration of 50 μg VSVMP/250 μg liposome complexes, 50 μg empty plasmid/250 μg liposome complexes or 0.9% NaCl solution, respectively, every 2 days for 3 weeks. Administration of VSVMP resulted in a significant inhibition in ascites formation, improvement in health condition and prolonged survival of the treated mice. Decreased peritoneum osmolarity and reduced tumor vascularity coincided with dramatic reductions in the VEGF level in ascites fluid and plasma. Examination of floating tumor cells collected from the peritoneal wash revealed an apparently increased number of apoptotic cells and profound downregulation of VEGF mRNA in the VSVMP-treated mice. Our data indicate for the first time that in BALB/c mice bearing H22 or MethA cell peritoneal tumors, VSVMP may inhibit VEGF production and suppress angiogenesis, consequently abolishing ascites formation.

Efficient inhibition of ovarian cancer by recombinant CXC chemokine ligand 10 delivered by novel biodegradable cationic heparin-polyethyleneimine nanogels

Currently, great interest is focused on the anti-neoplastic effects of CXC chemokine ligand 10 (IP-10/CXCL10). IP-10 has shown significant antitumor and anti-metastatic properties via immunological, antiangiogenic and anti-neoplastic mechanisms. However, very few studies on the antitumor activity of IP-10 in human ovarian cancer have been reported. The use of polymeric nanoparticles to deliver functional genes intraperitoneally holds much promise as an effective therapy for ovarian cancer. In our study, a recombinant plasmid expressing IP-10 (pVITRO-IP-10) was constructed, and biodegradable cationic heparin-polyethyleneimine (HPEI) nanogels were prepared to deliver pVITRO-IP-10 into SKOV3 human ovarian cancer cells. Transfection efficiency was detected by expression profiling of green fluorescent protein. The expression of IP-10 was determined using RT-PCR and western blot analysis. In vitro, cell proliferation was evaluated by MTT assay. Apoptosis was examined by Hoechst33258/PI staining and flow cytometry assays. The effect on the inhibition of angiogenesis was evaluated by tube formation assay using human umbilical vein endothelial cells (HUVECs). Moreover, a SKOV3 intraperitoneal ovarian carcinomatosis model was established to investigate the antitumor activity of HPEI+pVITRO-IP-10 complexes in nude mice. Tumor weights were evaluated during the treatment course. Cell proliferation and apoptosis were evaluated by Ki-67 immunochemical staining and TUNEL assay, and the antiangiogenic effect of pVITRO-IP-10 was assessed by CD31 immunochemical staining and alginate-encapsulated tumor cell assay. pVITRO-IP-10 was efficiently transfected into SKOV3 cells by HPEI nanogels. Intraperitoneal administration of HPEI+pVITRO-IP-10 complexes led to effective growth inhibition of ovarian cancer, in which tumor weight decreased by ~69.92% in the treatment group compared with that in the empty vector control group. Meanwhile, decreased cell proliferation, increased tumor cell apoptosis and reduction in angiogenesis were observed in the HPEI+pVITRO-IP-10 group compared with those in the control groups. These results indicated that HPEI nanogel delivery of pVITRO-IP-10 may be of value in the treatment against human ovarian cancer.

Myxoma virus-mediated oncolysis of ascites-derived human ovarian cancer cells and spheroids is impacted by differential AKT activity

OBJECTIVE

We propose that metastatic epithelial ovarian cancer (EOC) is a potential therapeutic target for the oncolytic agent, Myxoma virus (MYXV).

METHODS

Primary EOC cells were isolated from patient ascites and cultured as adherent cells or in suspension using Ultra Low-Attachment dishes. MYXV expressing green fluorescent protein was used to infect cells and spheroids. Infection was monitored by fluorescence microscopy, viral titering and immunoblotting for M-T7 and M130 virus protein expression, and cell viability by alamarBlue assay. Akti-1/2 (5 μM) and rapamycin (20 nM) were used to assay the role of PI3K-AKT signaling in mediating MYXV infection.

RESULTS

Ascites-derived EOC cells grown in adherent culture are effectively killed by MYXV infection. EOC cells grown in suspension to form three-dimensional EOC spheroids readily permit MYXV entry into cells, yet are protected from the cytopathic effects of late MYXV infection. Upon reattachment (to model secondary metastasis), EOC spheroids are re-sensitized to MYXV-mediated oncolysis. The critical determinant that facilitates efficient MYXV infection is the presence of an activated PI3K-AKT signaling pathway. Treatment with the specific AKT inhibitor Akti-1/2 reduces infection of monolayer EOC cells and spheroids. Direct infection of freshly-collected ascites demonstrated that 54.5% of patient samples were sensitive to MYXV-mediated oncolytic cell killing. We also demonstrate that factor(s) present in ascites may negatively impact MYXV infection and oncolysis of EOC cells, which may be due to a down-regulation in endogenous AKT activity.

CONCLUSIONS

Differential activity of AKT serves as the mechanistic basis for regulating MYXV-mediated oncolysis of EOC spheroids during key steps of the metastatic program. In addition, we provide the first evidence that MYXV oncolytic therapy may be efficacious for a significant proportion of ovarian cancer patients with metastatic disease.

Vesicular stomatitis virus matrix protein (VSVMP) inhibits the cell growth and tumor angiogenesis in oral squamous cell carcinoma

The purpose of this study was to investigate the anticancer property of vesicular stomatitis virus matrix protein (VSVMP) in oral squamous cell carcinoma (OSCC) via in vitro and in vivo approaches. In this study, we found that OSCC cells treated with VSVMP showed retarded cell growth in vitro. The percentage of apoptotic cells in VSVMP group was much higher than that of the control groups. Moreover, our in vivo experiments showed that the growth of tumor xenografts was significantly suppressed by VSVMP treatment without any obvious side effects. Further studies revealed that the suppression of tumor growth may be caused by the synergistic effect of VSVMP related cell apoptosis enhancing and tumor angiogenesis suppression, and the latter is most likely correlated with the suppression of VEGF pathway. This study indicated that VSVMP treatment can effectively inhibited the cell growth and tumor angiogenesis in OSCC without obvious adverse effects. Therefore, VSVMP might be a potential and efficient strategy for OSCC treatment.

The p53 upregulated modulator of apoptosis (PUMA) chemosensitizes intrinsically resistant ovarian cancer cells to cisplatin by lowering the threshold set by Bcl-x(L) and Mcl-1

Ovarian cancer is the number one cause of death from gynecologic malignancy. A defective p53 pathway is a hallmark of ovarian carcinoma. The p53 mutation correlates significantly with resistance to platinum-based chemotherapy, early relapse and shortened overall survival in ovarian cancer patients. PUMA (p53 upregulated modulator of apoptosis), a BH3-only Bcl-2 family protein, was recently identified as a transcriptional target of p53 and a potent apoptosis inducer in various cancer cells. In this study, we showed that the induction of PUMA by cisplatin was abolished in p53-deficient SKOV3 cells. Elevated expression of PUMA-induced apoptosis and sensitized A2780s and SKOV3 ovarian cancer cells to cisplatin, and the combination of PUMA and low-dose cisplatin, significantly suppressed xenograft tumor growth in vivo through enhanced induction of apoptosis compared with treatment with PUMA or cisplatin alone. The effects of PUMA were mediated by enhanced caspase activation and release of cytochrome c and Smac (second mitochondria-derived activator of caspase) into the cytosol. Furthermore, PUMA chemosensitized intrinsically resistant SKOV3 cells to cisplatin through downregulation of B-cell lymphoma-extra large (Bcl-x(L)) and myeloid cell leukemia sequence 1 (Mcl-1). PUMA-mediated Bcl-x(L) downregulation mainly happened at the transcription level, whereas PUMA-induced Mcl-1 down-regulation was associated with caspase-dependent cleavage and proteasome-mediated degradation. To our knowledge, these data suggest a new mechanism by which overexpression of PUMA enhances sensitivity of SKOV3 cells to cisplatin by lowering the threshold set simultaneously by Bcl-x(L) and Mcl-1. Taken together, our findings indicate that PUMA is an important modulator of therapeutic responses of ovarian cancer cells and is potentially useful as a chemosensitizer in ovarian cancer therapy.

Efficient inhibition of C-26 colon carcinoma by VSVMP gene delivered by biodegradable cationic nanogel derived from polyethyleneimine

Biodegradable cationic nanoparticles have promising application as a gene delivery system. In this article, heparin-polyethyleneimine (HPEI) nanogels were prepared, and these nanogels were developed as a nonviral gene vector. The transfection efficiency of HPEI nanogels was comparable with that of PEI25K, while the cytotoxicity was lower than that of PEI2K and much lower than that of PEI25K in vitro. These HPEI nanogels also had better blood compatibility than PEI25K. After intravenous administration, HPEI nanogels degraded, and the degradation products were excreted through urine. The plasmid expressing vesicular stomatitis virus matrix protein (pVSVMP) could be efficiently transfected into C-26 colon carcinoma cells by HPEI nanogels in vitro, inhibiting the cell proliferation through apoptosis induction. Intraperitoneal injection of pVSVMP/HPEI complexes efficiently inhibited the abdominal metastases of C-26 colon carcinoma through apoptosis induction (mean tumor weight in mice treated with pVSVMP/HPEI complex = 0.93 g and in control mice = 3.28 g, difference = 2.35 g, 95% confidence interval [CI] = 1.75-2.95 g, P < 0.001) and prolonged the survival of treated mice. Moreover, intravenous application of pVSVMP/HPEI complexes also inhibited the growth of pulmonary metastases of C-26 colon carcinoma through apoptosis induction. The HPEI nanogels delivering pVSVMP have promising application in treating colon carcinoma.

Efficacy of RNAi targeting of pyruvate kinase M2 combined with cisplatin in a lung cancer model

PURPOSE

Pyruvate kinase isoenzyme M2 (PKM2) is a key enzyme in aerobic glycolysis; inhibition of PKM2 leads to the tumor growth inhibition. In this study, the effects of combined treatment with cisplatin (DDP) and a plasmid that expresses a short hairpin RNA (shRNA) targeting PKM2 on the growth of human A549 xenograft lung cancer model were investigated.

METHODS

The expression of PKM2 in A549 cells was determined by immunofluorescence. PKM2 expression levels were evaluated by Western blot analysis. In a human A549 lung cancer xenograft model, the effects of treatment with shRNA, with or without cisplatin, on tumor volume were determined. Apoptosis and cell proliferation status were examined to determine the mechanisms of tumor growth inhibition.

RESULTS

Expression of shRNA targeting PKM2 resulted in inhibition of PKM2 expression in A549 cells. In the lung cancer xenograft model, average tumor volume in the group treated with both cisplatin and shRNA was statistically lower than those of other groups (P < 0.05). The levels of apoptotic cells were significantly higher in samples from animals in the combined treatment group than those from untreated animals (P < 0.05). The cell proliferation rate, as determined by counting cells labeled with an anti-phospho-histone H3, a marker for mitosis, was lower in samples from animals treated with both cisplatin and shRNA than in samples from other groups (P < 0.05).

CONCLUSIONS

Use of RNA interfering (RNAi) targeting PKM2 significantly inhibited tumor growth when combined with cisplatin in a human A549 lung cancer xenograft model. The enhanced antitumor activity of the combined treatment compared to treatment with shRNA alone may result in part from increased induction of apoptosis and augmented inhibition of cancer cell proliferation.

Targeting CD24 for treatment of ovarian cancer by short hairpin RNA

BACKGROUND AIMS

CD24 is markedly overexpressed in ovarian cancer and plays a critical role in ovarian cancer survival and metastasis, rendering it an interesting target for anti-tumor therapy. Using short hairpin RNA (shRNA) targeting CD24, we aimed to investigate the anti-tumor efficacy of CD24 knockdown in ovarian cancer cells in vitro and in vivo.

METHODS

CD24 shRNA vector (CD24-shRNA) and empty plasmid vector (EP) were transfected into ovarian cancer SKOV3 cells and the knockdown efficacy assessed by Western blot analysis. The effects of CD24 knockdown in SKOV3 cells in vitro, including cell viability and apoptosis, were determined using methyl thiazolyl blue tetrazolium bromide (MTT), flow cytometry and propidium iodide (PI) staining assays. The effects in vivo of CD24 knockdown on angiogenesis, cell proliferation and apoptosis were assessed using immunohistochemistry against CD31, proliferating cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) assays.

RESULTS

Transfection of CD24-shRNA effectively down-regulated CD24 expression in vitro and in vivo. Administration of CD24-shRNA into nude mice bearing ovarian cancer significantly suppressed tumor volume growth.

CONCLUSIONS

Knockdown of CD24 expression by CD24-shRNA significantly inhibited cell viability and induced apoptosis of SKOV3 cells in vitro. Administration with CD24-shRNA in vivo suppressed tumor volume increase by microvessel density (MVD) decrease, cell proliferation inhibition and apoptosis induction. All the data suggested that knockdown of CD24 by shRNA might be a potential therapeutic approach against human ovarian cancer.

The anti-condyloma acuminatum effects of interferon-inducible protein 10 in vitro

BACKGROUND

Interferon-inducible protein 10 (IP-10) has been reported to show an effective antiviral and antineoplastic role in various murine models.

AIM

To investigate the anti-condyloma acuminatum effect and human papillomavirus (HPV)-inhibiting efficacy of a recombinant plasmid encoding IP-10 in vitro.

METHODS

A recombinant plasmid DNA carrying IP-10 cDNA was constructed. Condyloma acuminatum tissue particles were transfected with IP-10 and examined for apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry techniques. Relative real-time polymerase chain reaction (PCR) was used to validate the HPV inhibited level of the treatment groups. Immunohistochemistry was used to determine the IP-10 expression on condyloma acuminatum tissues.

RESULTS

Transfected IP-10 was expressed mainly in the cytoplasm of the condyloma acuminatum tissues. Plentiful apoptosis was observed in condyloma acuminatum tissues transfected with IP-10. In addition, HPV expression was lower in IP-10-treated tissues than in control tissues.

CONCLUSIONS

These observations suggest that IP-10 has strong anti-condyloma acuminatum effects, inducing apoptosis and inhibiting HPV, and therefore may be a novel and potentially effective therapy for condyloma acuminatum.

Human alpha-defensin-1 inhibits growth of human lung adenocarcinoma xenograft in nude mice

Human alpha-defensin-1 (HNP1), a small antimicrobial peptide, shows cytotoxicity to tumor cells in vitro and inhibitory activity for pathologic neovascularization in vivo. Here, we did a gene therapy with a plasmid that expresses a secretable form of HNP1 for assaying its antitumor activity. The expression and secretion of HNP1 were determined by reverse transcription-PCR and ELISA in vitro. We found that expression of HNP1 in A549 tumor cells caused significant growth inhibition. This effect is most likely cell autonomous, as a significant amount of recombinant HNP1 protein was found to be accumulated in the cytoplasm by immunohistochemical staining using an anti-HNP1 antibody and the supernatant containing secreted HNP1 failed to produce any noticeable antitumor activity. Flow cytometry and Hoechst 33258 staining showed that the number of apoptotic cells among the A549 cells expressing recombinant HNP1 proteins was significantly greater than that of the nontransfected control cultures, suggesting that this growth-inhibitory activity was due to an apoptotic mechanism triggered by the intracellular HNP1. The antitumor activity of intracellularly expressed HNP1 was also shown in vivo. Decreased microvessel density and increased lymphocyte infiltration were observed in tumor tissue from HNP1-treated mice through histologic analysis. These results indicate that intracellularly expressed HNP1 induces tumor cell apoptosis, which inhibits tumor growth. The antiangiogenesis effect of HNP1 may contribute to its inhibitory activity in vivo, and HNP1 might involve the host immune response to tumor. These findings provide a rationale for developing HNP1-based gene therapy for cancer.