Neoadjuvant use of oncolytic herpes virus G47Δ prevents local recurrence after insufficient resection in tongue cancer models

A complete resection of tongue cancer is often difficult. We investigate the usefulness of administering G47Δ (teserpaturev), a triple-mutated oncolytic herpes simplex virus type 1, prior to resection. G47Δ exhibits good cytopathic effects and replication capabilities in all head and neck cancer cell lines tested. In an orthotopic SCCVII tongue cancer model of C3H/He mice, an intratumoral inoculation with G47Δ significantly prolongs the survival. Further, mice with orthotopic tongue cancer received neoadjuvant G47Δ (or mock) therapy with or without "hemilateral" resection, the maximum extent avoiding surgical deaths. Neoadjuvant G47Δ and resection led to 10/10 survival (120 days), whereas the survivals for G47Δ alone and resection alone were 6/10 and 5/10, respectively: all control animals died by day 11. Furthermore, 100% survival was achieved with neoadjuvant G47Δ therapy even when the resection area was narrowed to "partial," providing insufficient resection margins, whereas hemilateral resection alone caused death by local recurrence in half of the animals. G47Δ therapy caused increased number of tumor-infiltrating CD8+ and CD4+ cells, increased F4/80+ cells within the residual tongues, and increased expression of immune-related genes in and around the tumor. These results imply that neoadjuvant use of G47Δ is useful for preventing local recurrence after tongue cancer surgery.

Analysis of the value and safety of thyroid-stimulating hormone in the clinical efficacy of patients with thyroid cancer

BACKGROUND

Thyroid cancer (TC) is a common malignant tumor in the endocrine system. In recent years, the incidence and recurrence rates of TC have been raising due to increasing work pressure and irregular lifestyles. Thyroid-stimulating hormone (TSH) is a specific parameter for thyroid function screening. This study aims to explore the clinical value of TSH in regulating the progression of TC, so as to find a breakthrough for the early diagnosis and treatment of TC.

AIM

To explore the value and safety of TSH in the clinical efficacy of patients with TC.

METHODS

75 patients with TC admitted to the Department of Thyroid and Breast Surgery of our hospital from September 2019 to September 2021 were selected as the observation group, and 50 healthy subjects were selected as the control group during the same period. The control group was treated with conventional thyroid replacement therapy, and the observation group was treated with TSH suppression therapy. The soluble interleukin (IL)-2 receptor (sIL-2R), IL-17, IL-35 levels, free triiodothyronine (FT₃), free tetraiodothyronine (FT₄), CD3⁺, CD4⁺, CD8⁺, CD44V6, and tumor supplied group of factor (TSGF) levels were observed in the two groups. The occurrence of adverse reactions was compared between the two groups.

RESULTS

After treatment with different therapies, the levels of FT₃, FT₄, CD3⁺, and CD4⁺ in the observation group and the control group were higher than those before treatment, while the levels of CD8⁺, CD44V6, and TSGF were lower than those before treatment, and the differences were statistically significant (P < 0.05). More importantly, the levels of sIL-2R and IL-17 in the observation group were lower than those in the control group after 4 wk of treatment, while the levels of IL-35 were higher than those in the control group, and the differences were statistically significant (P < 0.05). The levels of FT₃, FT₄, CD3 ⁺, and CD4 ⁺ in the observation group were higher than those in the control group, and the levels of CD8⁺, CD44V6, and TSGF were lower than those in the control group. There was no significant difference in the overall incidence rate of adverse reactions between the two groups (P > 0.05).

CONCLUSION

TSH suppression therapy can improve the immune function of patients with TC, lower the CD44V6 and TSGF levels, and improve serum FT₃ and FT₄ levels. It demonstrated excellent clinical efficacy and a good safety profile.

Herpes simplex virus 1 as an oncolytic viral therapy for refractory cancers

The need for efficacious and non-toxic cancer therapies is paramount. Oncolytic viruses (OVs) are showing great promise and are introducing new possibilities in cancer treatment with their ability to selectively infect tumor cells and trigger antitumor immune responses. Herpes Simplex Virus 1 (HSV-1) is a commonly selected OV candidate due to its large genome, relative safety profile, and ability to infect a variety of cell types. Talimogene laherparevec (T-VEC) is an HSV-1-derived OV variant and the first and only OV therapy currently approved for clinical use by the United States Food and Drug Administration (FDA). This review provides a concise description of HSV-1 as an OV candidate and the genomic organization of T-VEC. Furthermore, this review focuses on the advantages and limitations in the use of T-VEC compared to other HSV-1 OV variants currently in clinical trials. In addition, approaches for future directions of HSV-1 OVs as cancer therapy is discussed.

Oncolytic Viruses: Immunotherapy Drugs for Gastrointestinal Malignant Tumors

Oncolytic virus therapy has advanced rapidly in recent years. Natural or transgenic viruses can target tumor cells and inhibit tumor growth and metastasis in various ways without interfering with normal cell and tissue function. Oncolytic viruses have a high level of specificity and are relatively safe. Malignant tumors in the digestive system continue to have a high incidence and mortality rate. Although existing treatment methods have achieved some curative effects, they still require further improvement due to side effects and a lack of specificity. Many studies have shown that oncolytic viruses can kill various tumor cells, including malignant tumors in the digestive system. This review discusses how oncolytic virus therapy improves malignant tumors in the digestive system from the point-of-view of basic and clinical studies. Also, the oncolytic virus anti-tumor mechanisms underpinning the therapeutic potential of oncolytic viruses are expounded. In all, we argue that oncolytic viruses might eventually provide therapeutic solutions to malignant tumors in the digestive system.

Oncolytic Herpes Simplex Virus-Based Therapies for Cancer

With the increased worldwide burden of cancer, including aggressive and resistant cancers, oncolytic virotherapy has emerged as a viable therapeutic option. Oncolytic herpes simplex virus (oHSV) can be genetically engineered to target cancer cells while sparing normal cells. This leads to the direct killing of cancer cells and the activation of the host immunity to recognize and attack the tumor. Different variants of oHSV have been developed to optimize its antitumor effects. In this review, we discuss the development of oHSV, its antitumor mechanism of action and the clinical trials that have employed oHSV variants to treat different types of tumor.

Current understanding of nonsurgical interventions for refractory differentiated thyroid cancer: a systematic review

Thyroid cancer incidence and related mortality is increasing year-on-year, and although treatment for early disease with surgery and radioiodine results in a 98% 5-year survival rate, recurrence and treatment refractory disease is evident in an unacceptable number of patients. Alternative treatment regimens have therefore been sought in the form of tyrosine kinase inhibitors, immunotherapy, vaccines, chimeric antigen receptor T-cell therapy and oncolytic viruses. The current review aims to consolidate knowledge and highlight the latest clinical trials using secondary therapies in thyroid cancer treatment, focusing on both in vitro and in vivo studies, which have investigated therapies other than radioiodine.

The rates of thyroid cancer and related deaths are increasing. Differentiated thyroid cancer is the most common type of thyroid cancer. Early disease can be treated with surgery and radioactive iodine with very good outcomes. However, this therapy does not work for a small number of patients making it important to find different (secondary) treatment options. This review summarizes the results of published research about secondary treatment options for differentiated thyroid cancer. Ongoing research including laboratory-based and clinical trials are also highlighted.

Neoadjuvant Use of Oncolytic Herpes Virus G47Δ Enhances the Antitumor Efficacy of Radiofrequency Ablation

G47Δ is a triple-mutated oncolytic herpes simplex virus type 1 designed to induce antitumor immune responses efficiently. We examine the usefulness of G47Δ as a neoadjuvant therapy for radiofrequency ablation (RFA), a standard local treatment for certain cancers such as liver cancer, but remote recurrences within the same organ often occur. In A/J mice harboring bilateral subcutaneous Neuro2a tumors, the left tumors were treated with G47Δ intratumoral injections followed by RFA. Whereas the RFA-treated tumors were all eradicated, the growth of the right tumors was evaluated and tumor-infiltrating lymphocytes were analyzed. The G47Δ+RFA treatment caused smaller volumes of right tumors, accompanied by increased CD8⁺/CD45⁺ T cells, compared with G47Δ monotherapy. After depletion of CD8⁺ T cells, the enhanced efficacy on the contralateral tumors was completely abolished. Neoadjuvant G47Δ led to rejection of rechallenged tumors, which was caused by efficient induction of specific antitumor immune responses shown by enzyme-linked immunospot (ELISPOT) assays. Treatment of tumor-harboring animals with an anti-programmed cell death 1 ligand 1 (PD-L1) antibody led to even greater efficacy on contralateral tumors. Our study indicates that the neoadjuvant use of G47Δ effectively enhances the efficacy of RFA via CD8⁺ T cell-dependent immunity that is further augmented by an immune checkpoint inhibitor.

Combining BRAF inhibition with oncolytic herpes simplex virus enhances the immune-mediated antitumor therapy of BRAF-mutant thyroid cancer

BACKGROUND

The aggressive clinical behavior of poorly differentiated and anaplastic thyroid cancers (PDTC and ATC) has proven challenging to treat, and survival beyond a few months from diagnosis is rare. Although 30%-60% of these tumors contain mutations in the BRAF gene, inhibitors designed specifically to target oncogenic BRAF have shown limited and only short-lasting therapeutic benefits as single agents, thus highlighting the need for improved treatment strategies, including novel combinations.

METHODS

Using a BRAFV600E-driven mouse model of ATC, we investigated the therapeutic efficacy of the combination of BRAF inhibition and oncolytic herpes simplex virus (oHSV). Analyses of samples from tumor-bearing mice were performed to immunologically characterize the effects of different treatments. These immune data were used to inform the incorporation of immune checkpoint inhibitors into triple combination therapies.

RESULTS

We characterized the immune landscape in vivo following BRAF inhibitor treatment and detected only modest immune changes. We, therefore, hypothesized that the addition of oncolytic virotherapy to BRAF inhibition in thyroid cancer would create a more favorable tumor immune microenvironment, boost the inflammatory status of tumors and improve BRAF inhibitor therapy. First, we showed that thyroid cancer cells were susceptible to infection with oHSV and that this process was associated with activation of the immune tumor microenvironment in vivo. Next, we showed improved therapeutic responses when combining oHSV and BRAF inhibition in vivo, although no synergistic effects were seen in vitro, further confirming that the dominant effect of oHSV in this context was likely immune-mediated. Importantly, both gene and protein expression data revealed an increase in activation of T cells and natural killer (NK) cells in the tumor in combination-treated samples. The benefit of combination oHSV and BRAF inhibitor therapy was abrogated when T cells or NK cells were depleted in vivo. In addition, we showed upregulation of PD-L1 and CTLA-4 following combined treatment and demonstrated that blockade of the PD-1/PD-L1 axis or CTLA-4 further improved combination therapy.

CONCLUSIONS

The combination of oHSV and BRAF inhibition significantly improved survival in a mouse model of ATC by enhancing immune-mediated antitumor effects, and triple combination therapies, including either PD-1 or CTLA-4 blockade, further improved therapy.

Oncolytic virus therapy in Japan: progress in clinical trials and future perspectives

Oncolytic virus therapy is a promising new option for cancer. It utilizes genetically engineered or naturally occurring viruses that selectively replicate in and kill cancer cells without harming normal cells. T-VEC (talimogene laherparepvec), a second-generation oncolytic herpes simplex virus type 1, was approved by the US Food and Drug Administration for the treatment of inoperable melanoma in 2015 and subsequently approved in Europe in 2016. Other oncolytic viruses using different parental viruses have also been tested in Phase III clinical trials and are ready for drug approval: Pexa-Vec (pexastimogene devacirepvec), an oncolytic vaccinia virus, CG0070, an oncolytic adenovirus, and REOLYSIN (pelareorep), an oncolytic reovirus. In Japan, as of May 2018, several oncolytic viruses have been developed, and some have already proceeded to clinical trials. In this review, we summarize clinical trials assessing oncolytic virus therapy that were conducted or are currently ongoing in Japan, specifically, T-VEC, the abovementioned oncolytic herpes simplex virus type 1, G47Δ, a third-generation oncolytic herpes simplex virus type 1, HF10, a naturally attenuated oncolytic herpes simplex virus type 1, Telomelysin, an oncolytic adenovirus, Surv.m-CRA, another oncolytic adenovirus, and Sendai virus particle. In the near future, oncolytic virus therapy may become an important and major treatment option for cancer in Japan.

Virotherapy as a Potential Therapeutic Approach for the Treatment of Aggressive Thyroid Cancer

Virotherapy is a novel cancer treatment based on oncolytic viruses (OVs), which selectively infect and lyse cancer cells, without harming normal cells or tissues. Several viruses, either naturally occurring or developed through genetic engineering, are currently under investigation in clinical studies. Emerging reports suggesting the immune-stimulatory property of OVs against tumor cells further support the clinical use of OVs for the treatment of lesions lacking effective therapies. Poorly differentiated thyroid carcinoma (PDTC) and anaplastic thyroid carcinoma (ATC), have a poor prognosis and limited treatment options. Therefore, several groups investigated the therapeutic potential of OVs in PDTC/ATC models producing experimental data sustaining the potential clinical efficacy of OVs in these cancer models. Moreover, the presence of an immunosuppressive microenvironment further supports the potential use of OVs in ATC. In this review, we present the results of the studies evaluating the efficacy of OVs alone or in combination with other treatment options. In particular, their potential therapeutic combination with multiple kinases inhibitors (MKIs) or immune checkpoint inhibitors are discussed.

Oncolytic virotherapy for anaplastic and poorly differentiated thyroid cancer: a promise or a clinical reality?

Oncolytic viruses (OVs) selectively infect and lyse cancer cells. A direct lytic effect of OVs has been theorized in the initial studies; however, the antineoplastic effect of OVs is also due to the induction of an immune response against cancer cells. Anaplastic thyroid cancer is one of the most aggressive human malignancies with a short survival time of about 6–12 months from the diagnosis. The lack of effective therapies has prompted to investigate the efficacy of OVs in anaplastic thyroid carcinoma. Different OVs have been tested in preclinical studies, either as single agents or in combinatorial treatments. In this review, the results of these studies are summarized and future perspective discussed.

Current status of clinical trials assessing oncolytic virus therapy for urological cancers

Oncolytic virus therapy has recently been recognized as a promising new option for cancer treatment. Oncolytic viruses replicate selectively in cancer cells, thus killing them without harming normal cells. Notably, T-VEC (talimogene laherparepvec, formerly called OncoVEX^GM-CSF ), an oncolytic herpes simplex virus type 1, was approved by the US Food and Drug Administration for the treatment of inoperable melanoma in October 2015, and was subsequently approved in Europe and Australia in 2016. The efficacies of many types of oncolytic viruses against urological cancers have been investigated in preclinical studies during the past decade, and some have already been tested in clinical trials. For example, a phase I trial of the third-generation oncolytic Herpes simplex virus type 1, G47Δ, in patients with prostate cancer was completed in 2016. We summarize the current status of clinical trials of oncolytic virus therapy in patients with the three major urological cancers: prostate, bladder and renal cell cancers. In addition to Herpes simplex virus type 1, adenoviruses, reoviruses, vaccinia virus, Sendai virus and Newcastle disease virus have also been used as parental viruses in these trials. We believe that oncolytic virus therapy is likely to become an important and major treatment option for urological cancers in the near future.

Oncolytic virus therapy: A new era of cancer treatment at dawn

Oncolytic virus therapy is perhaps the next major breakthrough in cancer treatment following the success in immunotherapy using immune checkpoint inhibitors. Oncolytic viruses are defined as genetically engineered or naturally occurring viruses that selectively replicate in and kill cancer cells without harming the normal tissues. T‐Vec (talimogene laherparepvec), a second‐generation oncolytic herpes simplex virus type 1 (HSV‐1) armed with GM‐CSF, was recently approved as the first oncolytic virus drug in the USA and Europe. The phase III trial proved that local intralesional injections with T‐Vec in advanced malignant melanoma patients can not only suppress the growth of injected tumors but also act systemically and prolong overall survival. Other oncolytic viruses that are closing in on drug approval in North America and Europe include vaccinia virus JX‐594 (pexastimogene devacirepvec) for hepatocellular carcinoma, GM‐CSF‐expressing adenovirus CG0070 for bladder cancer, and Reolysin (pelareorep), a wild‐type variant of reovirus, for head and neck cancer. In Japan, a phase II clinical trial of G47∆, a third‐generation oncolytic HSV‐1, is ongoing in glioblastoma patients. G47∆ was recently designated as a “Sakigake” breakthrough therapy drug in Japan. This new system by the Japanese government should provide G47∆ with priority reviews and a fast‐track drug approval by the regulatory authorities. Whereas numerous oncolytic viruses have been subjected to clinical trials, the common feature that is expected to play a major role in prolonging the survival of cancer patients is an induction of specific antitumor immunity in the course of tumor‐specific viral replication. It appears that it will not be long before oncolytic virus therapy becomes a standard therapeutic option for all cancer patients.

MiR-99a Inhibits Cell Proliferation and Tumorigenesis through Targeting mTOR in Human Anaplastic Thyroid Cancer

MicroRNAs (miRNAs) are emerging as critical regulators in carcinogenesis and tumor progression. Recently, miR-99a has been reported as a tumor suppressor gene in various human cancers, but its functions in the context of anaplastic thyroid cancer (ATC) remain unknown. In this study, we reported that miR-99a was commonly downregulated in ATC tissue specimens and cell lines with important functional consequences. Overexpression of miR-99a not only dramatically reduced ATC cell viability by inducing cell apoptosis and accumulation of cells at G1 phase, but also inhibited tumorigenicity in vivo. We then screened and identified a novel miR-99a target, mammalian target of rapamycin (mTOR), and it was further confirmed by luciferase assay. Up-regulation of miR-99a would markedly reduce the expression of mTOR and its downstream phosphorylated proteins (p-4E- BP1 and p-S6K1). Similar to restoring miR-99a expression, mTOR down-regulation suppressed cell viability and increased cell apoptosis, whereas restoration of mTOR expression significantly reversed the miR-99a antitumor activity and the inhibition of mTOR/p-4E-BP1/p-S6K1 signal pathway profile. In clinical specimens and cell lines, mTOR was commonly overexpressed and its protein levels were statistically inversely correlated with miR-99a expression. Taken together, our results demonstrated for the first time that miR-99a functions as a tumor suppressor and plays an important role in inhibiting the tumorigenesis through targeting the mTOR/p- 4E-BP1/p-S6K1 pathway in ATC cells. Given these, miR-99a may serve as a novel prognostic/diagnostic and therapeutic target for treating ATC.

The oncolytic herpes simplex virus vector, G47Δ, effectively targets tamoxifen-resistant breast cancer cells

The aim of the present study was to establish a tamoxifen-resistant cell line (MCF-7/TAM-R) and to investigate the therapeutic effect of G47Δ on this cell line both in vitro and in vivo. In the present study, the MCF-7/TAM-R monoclonal subline was established after exposing MCF-7 cells to tamoxifen for 21 days. Then, it was compared with a wild-type MCF-7 subline (MCF-7W), which was not treated with tamoxifen. Cell proliferation, viability, cell cycle and apoptosis analyses were carried out to examine the characteristics of the MCF-7/TAM-R cells. Both in vitro and in vivo toxicity studies were conducted to investigate the therapeutic effect of G47Δ on the MCF-7/TAM-R cells. Compared to the MCF-7W cells, we found that the MCF-7/TAM-R cells exhibited a higher proliferation ability (P<0.05) and a stronger resistance to the cytotoxic effects induced by 4-hydroxytamoxifen (4-OHT) (P<0.05). G47Δ demonstrated a high cytotoxic effect on both the MCF-7/TAM-R and MCF-7W cell lines. After being infected with G47Δ at an MOI of 0.01, >90% of the MCF-7/TAM-R and MCF-7W cells died on day 5. G47Δ induced cell cycle arrest in the G2/M phase. Furthermore, G47Δ inhibited tumor growth in subcutaneous tumor models of both MCF-7/TAM-R and MCF-7W. Thus, we conclude that G47Δ, a third generation oncolytic herpes simplex virus, is highly sensitive and safe in targeting tamoxifen-resistant breast cancer cells both in vitro and in vivo.