Vaccinia Virus GLV-1h153 Is Effective in Treating and Preventing Metastatic Triple-Negative Breast Cancer

Targeted Inhibition of p21 Promotes the Growth of Breast Cancer Cells and Impairs the Tumor-Killing Effect of the Vaccinia Virus

PURPOSE

Vaccinia virus is widely used as an oncolytic agent for human cancer therapy, and several versions of vaccinia virus have demonstrated robust antitumor effects in breast cancer. Most vaccinia viruses are modified by thymidine kinase (TK) deletion. The function of the cyclin-dependent kinase inhibitor p21 in breast cancer remains controversial. We explored the impact of p21 gene knockdown (KD) on breast cancer cells and whether p21 KD interferes with the antitumor effect of TK-negative vaccinia virus.

METHODS

p21 KD MDA-MB-231 and p21 KD MCF-7 cells were prepared, and cell proliferation and migration rates were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and scratch healing assays. The tumor growth of xenografts originating from p21KD MDA-MB-231 cells and control cells was compared in a mouse model. The colony formation and sphere-forming abilities of p21 KD breast cancer cells were also determined using low-melting agarose and serum-free culture. The tumor-killing effect of the vaccinia virus was determined in breast cancer cells and mouse models using an MTT assay and tumor cell xenografts.

RESULTS

p21 KD increased the growth and migration of MDA-MB-231 and MCF-7 cells and promoted the cell growth of MDA-MB-231 cells in mice, while decreasing the colony formation and sphere formation abilities. Expression of TK was reduced in p21 KD MDA-MB-231 cells. Oncolytic effects of both wild-type and TK-deleted vaccinia viruses were attenuated in p21KD MDA-MB-231 cells. The tumor-killing effect of TK-deleted vaccinia virus was also weakened in xenografted mice bearing p21 KD MDA-MB-231 cells.

CONCLUSION

Targeted inhibition of p21 accelerates the proliferation and migration of breast cancer cells and impairs the tumor-killing effect of vaccinia virus, suggesting that p21 levels in cancer cells interfere with vaccinia virus oncolytic therapy.

Joining Forces: The Combined Application of Therapeutic Viruses and Nanomaterials in Cancer Therapy

Cancer, on a global scale, presents a monumental challenge to our healthcare systems, posing a significant threat to human health. Despite the considerable progress we have made in the diagnosis and treatment of cancer, realizing precision cancer therapy, reducing side effects, and enhancing efficacy remain daunting tasks. Fortunately, the emergence of therapeutic viruses and nanomaterials provides new possibilities for tackling these issues. Therapeutic viruses possess the ability to accurately locate and attack tumor cells, while nanomaterials serve as efficient drug carriers, delivering medication precisely to tumor tissues. The synergy of these two elements has led to a novel approach to cancer treatment-the combination of therapeutic viruses and nanomaterials. This advantageous combination has overcome the limitations associated with the side effects of oncolytic viruses and the insufficient tumoricidal capacity of nanomedicines, enabling the oncolytic viruses to more effectively breach the tumor's immune barrier. It focuses on the lesion site and even allows for real-time monitoring of the distribution of therapeutic viruses and drug release, achieving a synergistic effect. This article comprehensively explores the application of therapeutic viruses and nanomaterials in tumor treatment, dissecting their working mechanisms, and integrating the latest scientific advancements to predict future development trends. This approach, which combines viral therapy with the application of nanomaterials, represents an innovative and more effective treatment strategy, offering new perspectives in the field of tumor therapy.

A recombinant oncolytic influenza virus expressing a PD-L1 antibody induces CD8+ T-cell activation via the cGas-STING pathway in mice with hepatocellular carcinoma

OBJECTIVE

To evaluate targeted killing of hepatocellular carcinoma (HCC) cells by a recombinant oncolytic influenza virus expressing a PD-L1 antibody (rgFlu/PD-L1) and to develop a novel immunotherapy for HCC.

METHODS

Using influenza virus reverse genetics, a recombinant oncolytic virus was generated in the background of the A/Puerto Rico/8/34 (PR8) virus, then identified via screening and passage in specific pathogen-free chicken embryos. Hepatocellular carcinoma cell killing by rgFlu/PD-L1 was confirmed in vitro and in vivo. Transcriptome analyses were used to explore PD-L1 expression and function. Western blotting revealed that PD-L1 activated the cGas-STING pathway.

RESULTS

rgFlu/PD-L1 expressed the PD-L1 heavy and light chain in PB1 and PA, respectively; PR8 served as the backbone. The hemagglutinin titer of rgFlu/PD-L1 was 2⁹, and the virus titer was 9-10 logTCID₅₀/mL. Electron microscopy revealed that the rgFlu/PD-L1 morphology and size were consistent with wild-type influenza virus. The MTS assay showed that rgFlu/PD-L1 induced significant killing of HCC cells but not normal cells. rgFlu/PD-L1 inhibited PD-L1 expression and induced apoptosis in HepG2 cells. Notably, rgFlu/PD-L1 controlled the viability and function of CD8⁺ T cells by activating the cGas-STING pathway.

CONCLUSION

rgFlu/PD-L1 activated the cGas-STING pathway in CD8⁺ T cells, causing them to kill HCC cells. This approach represents a novel immunotherapy for liver cancer.

Triple-Negative Breast Cancer: Basic Biology and Immuno-Oncolytic Viruses

Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer. TNBC diagnoses account for approximately one-fifth of all breast cancer cases globally. The lack of receptors for estrogen, progesterone, and human epidermal growth factor 2 (HER-2, CD340) results in a lack of available molecular-based therapeutics. This increases the difficulty of treatment and leaves more traditional as well as toxic therapies as the only available standards of care in many cases. Recurrence is an additional serious problem, contributing substantially to its higher mortality rate as compared to other breast cancers. Tumor heterogeneity also poses a large obstacle to treatment approaches. No driver of tumor development has been identified for TNBC, and large variations in mutational burden between tumors have been described previously. Here, we describe the biology of six different subtypes of TNBC, based on differential gene expression. Subtype differences can have a large impact on metastatic potential and resistance to treatment. Emerging antibody-based therapeutics, such as immune checkpoint inhibitors, have available targets for small subsets of TNBC patients, leading to partial responses and relatively low overall efficacy. Immuno-oncolytic viruses (OVs) have recently become significant in the pursuit of effective treatments for TNBC. OVs generally share the ability to ignore the heterogeneous nature of TNBC cells and allow infection throughout a treated tumor. Recent genetic engineering has allowed for the enhancement of efficacy against certain tumor types while avoiding the most common side effects in non-cancerous tissues. In this review, TNBC is described in order to address the challenges it presents to potential treatments. The OVs currently described preclinically and in various stages of clinical trials are also summarized, as are their strategies to enhance therapeutic potential.

Identification of oncolytic vaccinia restriction factors in canine high-grade mammary tumor cells using single-cell transcriptomics

Mammary carcinoma, including triple-negative breast carcinomas (TNBC) are tumor-types for which human and canine pathologies are closely related at the molecular level. The efficacy of an oncolytic vaccinia virus (VV) was compared in low-passage primary carcinoma cells from TNBC versus non-TNBC. Non-TNBC cells were 28 fold more sensitive to VV than TNBC cells in which VV replication is impaired. Single-cell RNA-seq performed on two different TNBC cell samples, infected or not with VV, highlighted three distinct populations: naïve cells, bystander cells, defined as cells exposed to the virus but not infected and infected cells. The transcriptomes of these three populations showed striking variations in the modulation of pathways regulated by cytokines and growth factors. We hypothesized that the pool of genes expressed in the bystander populations was enriched in antiviral genes. Bioinformatic analysis suggested that the reduced activity of the virus was associated with a higher mesenchymal status of the cells. In addition, we demonstrated experimentally that high expression of one gene, DDIT4, is detrimental to VV production. Considering that DDIT4 is associated with a poor prognosis in various cancers including TNBC, our data highlight DDIT4 as a candidate resistance marker for oncolytic poxvirus therapy. This information could be used to design new generations of oncolytic poxviruses. Beyond the field of gene therapy, this study demonstrates that single-cell transcriptomics can be used to identify cellular factors influencing viral replication.

The identification of cellular genes influencing viral replication/propagation has been studied using hypothesis-driven approaches and/or high-throughput RNA interference screens. In the present report, we propose a methodology based on single-cell transcriptomics. We have studied, in the context of oncolytic virotherapy, the susceptibility of different grades of primary low-passage mammary carcinoma cells of canine origin to an oncolytic vaccinia virus (VV). We highlight a fault in replication of VV in cells that originated from high-grade triple-negative breast carcinomas (TNBC). Single-cell RNA-seq performed on TNBC cell samples infected with VV suggested that the reduced activity of the virus was associated with a higher mesenchymal status of the cells. We also demonstrate that high expression of one gene, DDIT4, is detrimental to VV production. Considering that DDIT4 is associated with a poor prognosis in various cancers including TNBC, our data highlight DDIT4 as a candidate resistance marker for oncolytic poxvirus therapy. Beyond the field of cancer gene therapy, we demonstrate here that single-cell transcriptomics increases the arsenal of tools available to identify cellular factors influencing viral replication.

Tumor suppressor role of microRNA-1296 in triple-negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis, which lacks effective targeted therapies. There is an urgent need to better understand the underlying molecular mechanisms of TNBC aggressiveness and identify novel, efficient targets for therapeutic intervention.

METHODS

miRNA qRT-PCR was used to determine the expression of miR-1296 in cell lines. The miR-1296 overexpression effects in TNBC cell lines were investigated using assays of colony formation, cell cycle and apoptosis. Immunoblotting was performed to determine the expression of the miR-1296 target protein, and luciferase assays were performed to confirm the target of miR-1296 action.

RESULTS

miR-1296 expression was significantly suppressed in TNBC cell lines and tissues samples. Overexpression of miR-1296 significantly suppressed cell proliferation of two TNBC cell lines when compared to control miRNA-expressing cells. A significant decrease in the S-phase of the cell cycle was observed following miR-1296 overexpression, accompanied by induction of apoptosis in TNBC cells. Cyclin D1 (CCND1) was identified as a target of miR-1296 action. miR-1296 overexpression significantly suppressed the luciferase activity of reporter plasmid containing the 3'UTR of CCND1 and protein expression levels of CCND1 in TNBC cells. The effects of miR-1296 overexpression on TNBC cell growth were reversed by CCND1 overexpression. miR-1296 expression sensitized TNBC cells to cisplatin treatment.

CONCLUSION

Our results demonstrate a novel tumor suppressor role for miR-1296 in triple-negative breast cancer cell lines, identify CCND1 as its target of action, and demonstrate a potential role for miR-1296 in sensitizing breast cancer cells to cisplatin.

Viruses as nanomedicine for cancer

Oncolytic virotherapy, a type of nanomedicine in which oncolytic viruses (OVs) are used to selectively infect and lyse cancer cells, is an emerging field in cancer therapy. Some OVs exhibit a specific tropism for cancer cells, whereas others require genetic modification to enhance their binding with and entry into cancer cells. OVs both kill tumor cells and induce the host’s immune response against tumor cells. Armed with antitumor cellular molecules, antibodies, and/or in combination with anticancer drugs, OVs can accelerate the lysis of cancer cells. Among the OVs, vaccinia virus has been the focus of preclinical and clinical research because of its many favorable properties. In this review, the basic mechanisms of action of OVs are presented, including their entry, survival, tumor lysis, and immune activation, and the latest research in vaccinia virus-based virotherapy and its status as an anticancer nanomedicine in prospective clinical trials are discussed.

Murine model of hepatic breast cancer

BACKGROUND AND AIMS

Breast cancer is the most common cancer in women and the second leading cause of cancer-related deaths in this population. Breast cancer related deaths have declined due to screening and adjuvant therapies, yet a driving clinical need exists to better understand the cause of the deadliest aspect of breast cancer, metastatic disease. Breast cancer metastasizes to several distant organs, the liver being the third most common site. To date, very few murine models of hepatic breast cancer exist.

METHODS

In this study, a novel murine model of liver breast cancer using the MDA-MB-231 cell line is introduced as an experimental (preclinical) model.

RESULTS

Histological typing revealed consistent hepatic breast cancer tumor foci. Common features of the murine model were vascular invasion, lung metastasis and peritoneal seeding.

CONCLUSIONS

The novel murine model of hepatic breast cancer established in this study provides a tool to be used to investigate mechanisms of hepatic metastasis and to test potential therapeutic interventions.

An overview of triple-negative breast cancer

PURPOSE

Triple-negative breast cancer (TNBC) is a heterogeneous group of tumors comprising various breast cancers simply defined by the absence of estrogen receptor, progesterone receptor and overexpression of human epidermal growth factor receptor 2 gene. In this review, we discuss the epidemiology, risk factors, clinical characteristics and prognostic variables of TNBC, and present the summary of recommended treatment strategies and all other available treatment options.

METHODS

We performed a systematic literature search using Medline and selected those articles which seemed relevant for this review. In addition, the ClinicalTrials.gov was also scanned for ongoing trials.

RESULTS

TNBC accounts for 10-20 % of all invasive breast cancers and has been found to be associated with African-American race, younger age, higher grade and mitotic index, and more advanced stage at diagnosis. Locoregional treatment is similar to other invasive breast cancer subtypes and involves surgery-mastectomy with or without adjuvant radiotherapy or breast conservation followed by adjuvant radiotherapy. Due to lack of drug-targetable receptors, chemotherapy is the only recommended systemic treatment to improve disease outcome. TNBC is sensitive to chemotherapy as demonstrated by high pathological complete response rates achieved after neoadjuvant chemotherapy, and this approach also allows for breast-conserving surgery. The peak risk of relapse is at 3 years after surgery, thereafter recurrence risk rapidly decreases. Survival after metastatic relapse is shorter as compared to other breast cancer subtypes, treatment options are few and response rates are poor and lack durability. Important molecular characteristics have now been identified that can subdivide this group of breast cancers further and can provide alternative systemic therapies.

CONCLUSIONS

To improve therapeutic outcome of TNBC, reliable predictive biomarkers and newer drugs against the known molecular pathways are required.

Silk-elastin-like protein polymer matrix for intraoperative delivery of an oncolytic vaccinia virus

BACKGROUND

Oncolytic viral efficacy may be limited by the penetration of the virus into tumors. This may be enhanced by intraoperative application of virus immediately after surgical resection.

METHODS

Oncolytic vaccinia virus GLV-1h68 was delivered in silk-elastin-like protein polymer (SELP) in vitro and in vivo in anaplastic thyroid carcinoma cell line 8505c in nude mice.

RESULTS

GLV-1h68 in SELP infected and lysed anaplastic thyroid cancer cells in vitro equally as effectively as in phosphate-buffered saline (PBS), and at 1 week retains a thousand fold greater infectious plaque-forming units. In surgical resection models of residual tumor, GLV-1h68 in SELP improves tumor control and shows increased viral β-galactosidase expression as compared to PBS.

CONCLUSION

The use of SELP matrix for intraoperative oncolytic viral delivery protects infectious viral particles from degradation, facilitates sustained viral delivery and transgene expression, and improves tumor control. Such optimization of methods of oncolytic viral delivery may enhance therapeutic outcomes.

Promising oncolytic agents for metastatic breast cancer treatment

New therapies for metastatic breast cancer patients are urgently needed. The long-term survival rates remain unacceptably low for patients with recurrent disease or disseminated metastases. In addition, existing therapies often cause a variety of debilitating side effects that severely impact quality of life. Oncolytic viruses constitute a developing therapeutic modality in which interest continues to build due to their ability to spare normal tissue while selectively destroying tumor cells. A number of different viruses have been used to develop oncolytic agents for breast cancer, including herpes simplex virus, adenovirus, vaccinia virus, measles virus, reovirus, and others. In general, clinical trials for several cancers have demonstrated excellent safety records and evidence of efficacy. However, the impressive tumor responses often observed in preclinical studies have yet to be realized in the clinic. In order for the promise of oncolytic virotherapy to be fully realized for breast cancer patients, effectiveness must be demonstrated in metastatic disease. This review provides a summary of oncolytic virotherapy strategies being developed to target metastatic breast cancer.

Gene therapy using therapeutic and diagnostic recombinant oncolytic vaccinia virus GLV-1h153 for management of colorectal peritoneal carcinomatosis

BACKGROUND

Peritoneal carcinomatosis (PC) is a terminal progression of colorectal cancer (CRC). Poor response to cytoreductive operation and chemotherapy coupled with the inability to reliably track disease progression by the use of established diagnostic methods, make this a deadly disease. We examined the effectiveness of the oncolytic vaccinia virus GLV-1h153 as a therapeutic and diagnostic vehicle. We believe that viral expression of the human sodium iodide transporter (hNIS) provides both real-time monitoring of viral therapy and effective treatment of colorectal peritoneal carcinomatosis (CRPC).

METHODS

Infectivity and cytotoxic effect of GLV-1h153 on CRC cell lines was assayed in vitro. Viral replication was examined by standard viral plaque assays. Orthotopic CRPC xenografts were generated in athymic nude mice and subsequently administered GLV-1h153 intraperitoneally. A decrease in tumor burden was assessed by mass. Orthotopic tumors were visualized by single-photon emission computed tomography/computed tomography after Iodine ((131)I) administration and by fluorescence optical imaging.

RESULTS

GLV-1h153 infected and killed CRC cells in a time- and concentration-dependent manner. Viral replication demonstrated greater than a 2.35 log increase in titer over 4 days. Intraperitoneal treatment of orthotopic CRPC xenografts resulted in a substantial decrease in tumor burden. Infection of orthotopic xenografts was therapeutic and facilitated monitoring by (131)I-single-photon emission computed tomography/computed tomography via expression of hNIS in infected tissue.

CONCLUSION

GLV-1h153 kills CRC in vitro effectively and decreases tumor burden in vivo. We demonstrate that GLV-1h153 can be used as an agent to provide accurate delineation of tumor burden in vivo. These findings indicate that GLV-1h153 has potential for use as a therapeutic and diagnostic agent in the treatment of CRPC.

Molecular imaging of oncolytic viral therapy

Oncolytic viruses have made their mark on the cancer world as a potential therapeutic option, with the possible advantages of reduced side effects and strengthened treatment efficacy due to higher tumor selectivity. Results have been so promising, that oncolytic viral treatments have now been approved for clinical trials in several countries. However, clinical studies may benefit from the ability to noninvasively and serially identify sites of viral targeting via molecular imaging in order to provide safety, efficacy, and toxicity information. Furthermore, molecular imaging of oncolytic viral therapy may provide a more sensitive and specific diagnostic technique to detect tumor origin and, more importantly, presence of metastases. Several strategies have been investigated for molecular imaging of viral replication broadly categorized into optical and deep tissue imaging, utilizing several reporter genes encoding for fluorescence proteins, conditional enzymes, and membrane protein and transporters. Various imaging methods facilitate molecular imaging, including computer tomography, magnetic resonance imaging, positron emission tomography, single photon emission CT, gamma-scintigraphy, and photoacoustic imaging. In addition, several molecular probes are used for medical imaging, which act as targeting moieties or signaling agents. This review will explore the preclinical and clinical use of in vivo molecular imaging of replication-competent oncolytic viral therapy.

A novel vaccinia virus with dual oncolytic and anti-angiogenic therapeutic effects against triple-negative breast cancer

Vascular endothelial growth factor (VEGF) expression is higher in triple-negative breast cancers (TNBC) compared to other subtypes and is reported to predict incidence of distant metastases and shorter overall survival. We investigated the therapeutic impact of a vaccinia virus (VACV) GLV-1h164 (derived from its parent virus GLV-1h100), encoding a single-chain antibody (scAb) against VEGF (GLAF-2) in an orthotopic TNBC murine model. GLV-1h164 was tested against multiple TNBC cell lines. Viral infectivity, cytotoxicity, and replication were determined. Mammary fat pad tumors were generated in athymic nude mice using MDA-MB-231 cells. Xenografts were treated with GLV-1h164, GLV-1h100, or PBS and followed for tumor growth. Viral infectivity was time- and concentration-dependent. GLV-1h164 killed TNBC cell lines in a dose-dependent fashion with greater than 90% cytotoxicity within 4 days at a multiplicity of infection of 5.0. In vitro, cytotoxicity of GLV-1h164 was identical to GLV-1h100. GLV-1h164 replicated efficiently in all cell lines with an over 400-fold increase in copy numbers from the initial viral dose within 4 days. In vivo, mean tumor volumes after 2 weeks of treatment were 73, 191, and 422 mm(3) (GLV-1h164, GLV-1h100, and PBS, respectively) (p < 0.05). Both in vivo Doppler ultrasonography and immuno-staining showed decreased neo-angiogenesis in GLV-1h164-treated tumors compared to both GLV-1h100 and PBS controls (p < 0.05). This is the first study to demonstrate efficient combination of oncolytic and anti-angiogenic activity of a novel VACV on TNBC xenografts. Our results suggest that GLV-1h164 is a promising therapeutic agent that warrants testing for patients with TNBC.

Oncolytic Poxviruses

Current standard treatments of cancer can prolong survival of many cancer patients but usually do not effectively cure the disease. Oncolytic virotherapy is an emerging therapeutic for the treatment of cancer that exploits replication-competent viruses to selectively infect and destroy cancerous cells while sparing normal cells and tissues. Clinical and/or preclinical studies on oncolytic viruses have revealed that the candidate viruses being tested in trials are remarkably safe and offer potential for treating many classes of currently incurable cancers. Among these candidates are vaccinia and myxoma viruses, which belong to the family Poxviridae and possess promising oncolytic features. This article describes poxviruses that are being developed for oncolytic virotherapy and summarizes the outcomes of both clinical and preclinical studies. Additionally, studies demonstrating superior efficacy when poxvirus oncolytic virotherapy is combined with conventional therapies are described.

Role of MAPK in oncolytic herpes viral therapy in triple-negative breast cancer

Triple-negative breast cancers (TNBCs) have poor clinical outcomes owing to a lack of targeted therapies. Activation of the MEK/MAPK pathway in TNBC has been associated with resistance to conventional chemotherapy and biologic agents and has a significant role in poor clinical outcomes. NV1066, a replication-competent herpes virus, infected, replicated in and killed all TNBC cell lines (MDA-MB-231, HCC1806, HCC38, HCC1937, HCC1143) tested. Greater than 90% cell kill was achieved in more-sensitive lines (MDA-MB-231, HCC1806, HCC38) by day 6 at a multiplicity of infection (MOI) of 0.1. In less-sensitive lines (HCC1937, HCC1143), NV1066 still achieved >70% cell kill by day 7 (MOI 1.0). In vivo, mean volume of flank tumors 14 days after treatment with NV1066 was 57 versus 438 mm(3) in controls (P=0.002). NV1066 significantly downregulated p-MAPK activation by 48 h in all cell lines in vitro and in MDA-MB-231 xenografts in vivo. NV1066 demonstrated synergistic effects with a MEK inhibitor, PD98059 in vitro. We demonstrate that oncolytic viral therapy (NV1066) effectively treats TNBC with correlation to decreased MEK/MAPK signaling. These findings merit future studies investigating the potential role of NV1066 as a sensitizing agent for conventional chemotherapeutic and biologic agents by downregulating the MAPK signaling pathway.

Viral warfare! Front-line defence and arming the immune system against cancer using oncolytic vaccinia and other viruses

BACKGROUND

Despite mankind's many achievements, we are yet to find a cure for cancer. We are now approaching a new era which recognises the promise of harnessing the immune system for anti-cancer therapy. Pathogens have been implicated for decades as potential anti-cancer agents, but implementation into clinical therapy has been plagued with significant drawbacks. Newer 'designer' agents have addressed some of these concerns, in particular, a new breed of oncolytic virus: JX-594, a genetically engineered pox virus, is showing promise.

OBJECTIVE

To review the current literature on the use of oncolytic viruses in the treatment of cancer; both by direct oncolysis and stimulation of the immune system. The review will provide a background and historical progression for the surgeon on tumour immunology, and the interplay between oncolytic viruses, immune cells, inflammation on tumourigenesis.

METHODS

A literature review was performed using the Medline database.

CONCLUSIONS

Viral therapeutics hold promise as a novel treatment modality for the treatment of disseminated malignancy. It provides a multi-pronged attack against tumour burden; direct tumour cell lysis, exposure of tumour-associated antigens (TAA), induction of immune danger signals, and recognition by immune effector cells.

Vaccinia virus GLV-1h153 in combination with 131I shows increased efficiency in treating triple-negative breast cancer

We investigated the therapeutic efficacy of a replication-competent oncolytic vaccinia virus, GLV-1h153, carrying human sodium iodide symporter (hNIS), in combination with radioiodine in an orthotopic triple-negative breast cancer (TNBC) murine model. In vitro viral infection was confirmed by immunoblotting and radioiodine uptake assays. Orthotopic xenografts (MDA-MB-231 cells) received intratumoral injection of GLV-1h153 or PBS. One week after viral injection, xenografts were randomized into 4 treatment groups: GLV-1h153 alone, GLV-1h153 and (131)I (∼ 5 mCi), (131)I alone, or PBS, and followed for tumor growth. Kruskal-Wallis and Wilcoxon tests were performed for statistical analysis. Radiouptake assay showed a 178-fold increase of radioiodine uptake in hNIS-expressing infected cells compared with PBS control. Systemic (131)I-iodide in combination with GLV-1h153 resulted in a 6-fold increase in tumor regression (24 compared to 146 mm(3) for the virus-only treatment group; P<0.05; d 40). We demonstrated that a novel vaccinia virus, GLV-1h153, expresses hNIS, increases the expression of the symporter in TNBC cells, and serves both as a gene marker for noninvasive imaging of virus and as a vehicle for targeted radionuclide therapy with (131)I.

An oncolytic vaccinia virus expressing the human sodium iodine symporter prolongs survival and facilitates SPECT/CT imaging in an orthotopic model of malignant pleural mesothelioma

BACKGROUND

The purpose of this work was to examine the ability of an oncolytic vaccinia virus expressing the human sodium iodine transporter (hNIS) to provide real time monitoring of viral therapy and effective treatment of malignant pleural mesothelioma (MPM).

METHODS

Infectivity and cytotoxic effects of GLV-1h153 on mesothelioma cell lines of all histologic subtypes were assayed in vitro. Viral replication was examined by standard viral plaque assay. Orthotopic MPM xenografts were generated in athymic nude mice, treated with intrapleural GLV-1h153, and assessed for effect on tumor burden and survival. Orthotopic tumors were also imaged on single photon emission computed tomography (SPECT)/computed tomography (CT) after (131)I administration.

RESULTS

GLV-1h153-infected and killed all cell lines in a time- and concentration-dependent manner. Viral replication demonstrated a >2.5-log increase in titer over 4 days. Intrapleural treatment of orthotopic MPM xenografts resulted in a significant decrease in tumor burden 1 week after treatment and an improvement in survival. Infection of orthotopic xenografts was both therapeutic and facilitated monitoring by (131)I-SPECT/CT via expression of hNIS in infected tissue.

CONCLUSION

Our results suggest that GLV-1h153 may be a promising therapeutic agent for MPM and warrants further investigation.

Expression and regulatory function of miRNA-182 in triple-negative breast cancer cells through its targeting of profilin 1

We aimed to evaluate the expression of microRNA-182 (miR-182) in triple-negative breast cancer (TNBC) tissues and the TNBC cell line MDA-MB-231 and to investigate the effects of mirR-182 on the cellular behavior of MDA-MB-231 and the expression of the target gene profilin 1 (PFN1), thus providing new methods and new strategies for the treatment of TNBC. Quantitative real-time PCR (qRT-PCR) was utilized to evaluate the expression of miR-182 in TNBC tissues, relatively normal tissues adjacent to TNBC and the TNBC cell line MDA-MB-231. Forty-eight hours after the MDA-MB-231 cells were transfected with the miR-182 inhibitor, qRT-PCR was utilized to detect the changes in miR-182 expression levels, and an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was utilized to determine the effects of miR-182 on cell viability. Flow cytometry was adopted to determine whether miR-182 affects the proliferation rates and apoptosis levels of the MDA-MB-231 cells. The transwell migration assay method was used to investigate the effects of miR-182 on the migration of the MDA-MB-231 cells. A luciferase reporter gene system was applied to validate that PFN1 was the target gene of miR-182. Western blot was used to measure the effects of miR-182 on the PFN1 protein expression levels in the cells. qRT-PCR results showed that compared with the relatively normal tissues adjacent to TNBC, miR-182 expression was significantly increased in the TNBC tissues and the MDA-MB-231 cells (p<0.01). Compared with the control group, MDA-MB-231 cells transfected with the miR-182 inhibitor and incubated for 48 h showed significantly decreased miR-182 expression (p<0.01). The results of an MTT assay showed that inhibition of miR-182 in MDA-MB-231 cells led to significantly reduced cell viability (p<0.05). Flow cytometry analysis indicated that inhibition of miR-182 expression resulted in significantly decreased cell proliferation (p<0.05) and significantly increased levels of apoptosis (p<0.05). The results of a transwell migration assay showed that after inhibited of miR-182 expression, the number of cells passing through the transwell membranes was significantly decreased (p<0.05). The results from a luciferase reporter gene system showed that compared with the control group, the relative luciferase activity of the group transfected with the miR-182 inhibitor was significantly increased (p<0.05). Western blot analysis showed that compared with the control group, PFN1 protein expression levels were significantly increased in the MDA-MB-231 cells transfected with the miR-182 inhibitor and incubated for 48 h (p<0.05). In conclusion, miR-182 is upregulated in TNBC tissues and cells. It promotes the proliferation and invasion of MDA-MB-231 cells and could negatively regulate PFN1 protein expression. Treatment strategies utilizing inhibition of miR-182 expression or overexpression of the PFN1 gene might benefit patients with TNBC.