Additional effects of engineered stem cells expressing a therapeutic gene and interferon-β in a xenograft mouse model of endometrial cancer

Enhanced anti-tumor efficacy with multi-transgene armed mesenchymal stem cells for treating peritoneal carcinomatosis

BACKGROUND

Mesenchymal stem cells (MSCs) have garnered significant interest for their tumor-tropic property, making them potential therapeutic delivery vehicles for cancer treatment. We have previously shown the significant anti-tumour activity in mice preclinical models and companion animals with naturally occurring cancers using non-virally engineered MSCs with a therapeutic transgene encoding cytosine deaminase and uracil phosphoribosyl transferase (CDUPRT) and green fluorescent protein (GFP). Clinical studies have shown improved response rate with combinatorial treatment of 5-fluorouracil and Interferon-beta (IFNb) in peritoneal carcinomatosis (PC). However, high systemic toxicities have limited the clinical use of such a regime.

METHODS

In this study, we evaluated the feasibility of intraperitoneal administration of non-virally engineered MSCs to co-deliver CDUPRT/5-Flucytosine prodrug system and IFNb to potentially enhance the cGAS-STING signalling axis. Here, MSCs were engineered to express CDUPRT or CDUPRT-IFNb. Expression of CDUPRT and IFNb was confirmed by flow cytometry and ELISA, respectively. The anti-cancer efficacy of the engineered MSCs was evaluated in both in vitro and in vivo model. ES2, HT-29 and Colo-205 were cocultured with engineered MSCs at various ratio. The cell viability with or without 5-flucytosine was measured with MTS assay. To further compare the anti-cancer efficacy of the engineered MSCs, peritoneal carcinomatosis mouse model was established by intraperitoneal injection of luciferase expressing ES2 stable cells. The tumour burden was measured through bioluminescence tracking.

RESULTS

Firstly, there was no changes in phenotypes of MSCs despite high expression of the transgene encoding CDUPRT and IFNb (CDUPRT-IFNb). Transwell migration assays and in-vivo tracking suggested the co-expression of multiple transgenes did not impact migratory capability of the MSCs. The superiority of CDUPRT-IFNb over CDUPRT expressing MSCs was demonstrated in ES2, HT-29 and Colo-205 in-vitro. Similar observations were observed in an intraperitoneal ES2 ovarian cancer xenograft model. The growth of tumor mass was inhibited by ~ 90% and 46% in the mice treated with MSCs expressing CDUPRT-IFNb or CDUPRT, respectively.

CONCLUSIONS

Taken together, these results established the effectiveness of MSCs co-expressing CDUPRT and IFNb in controlling and targeting PC growth. This study lay the foundation for the development of clinical trial using multigene-armed MSCs for PC.

The roles and therapeutic applications of cytokines in endometrial cancer

Endometrial cancer (EC) is a common gynecological cancer globally and the most frequent gynecologic malignancy in industrialized countries. Patients are typically diagnosed when the disease is still restricted to the uterus. 5-year overall survival ranges from 70 % to 90 % in patients without metastatic disease; however, the metastatic form of the disease affects 16 % of EC patients, with a 5-year survival rate of 16.8 %. The immune system can detect abnormal cells as non-self in the early stages of carcinogenesis, producing the appropriate pro-inflammatory environment to eliminate cancer cells. In a second phase, cancer cells use various immune-editing systems to alter the profile of the immune response from pro to anti-inflammatory, resulting in immune escape. The directors of this immune switching mechanism are cytokines. Studies have reported the increased expression of several pro-and anti-inflammatory cytokines in EC tissues and cell lines, including Interleukin (IL)- 6, IL-8, IL-31, IL-33, IL-10, TGF-β, VEGF, and IL-1Ra. Immune cells producing these cytokines have also been reported to be present in EC tissues. Therefore, in this study, we aimed to show the possible mechanisms of the mentioned cytokines on EC progression, as well as the most current and prospective advancements in cytokine-based therapeutic applications.

A promising therapeutic strategy for metastatic gestational trophoblastic disease: Engineered anticancer gene-expressing stem cells to selectively target choriocarcinoma

Gestational trophoblastic disease (GTD) is an unusual disease occurring in pregnancy that originates from abnormal trophoblastic cells and comprises a group of diseases with different properties of invasion, metastasis and recurrence. The GTD group includes hydatidiform moles and gestational trophoblastic neoplasms (GTNs), with GTNs being divided into invasive moles, choriocarcinoma, placental site trophoblastic tumors and epithelioid trophoblastic tumors. The present review focuses on current effective treatments for GTD, including conventional and novel promising direct enzyme prodrug therapies (DEPTs). Conventional therapies, such as chemotherapy and hysterectomy, are currently used in a clinical setting; however, the use of diverse DEPTs, including antibody-DEPT and gene-DEPT is also being attempted to cure GTNs. In addition, gene delivery tools using genetically engineered neural stem cells (NSCs) are presently being examined for the treatment of GTNs. The tumor-tropism of NSCs by chemoattractant factors is a unique characteristic of these cells and can serve as a vehicle to deliver anticancer agents. Previous studies have demonstrated that injection with NSC-expressing suicide genes into xenograft animal models has a significant inhibitory effect on tumor growth. Stem cells can be genetically engineered to express anticancer genes, which migrate to the metastatic sites and selectively target cancer cells, and are considered to effectively target metastatic GTNs. However, the safety issue of stem cell therapy, such as tumorigenesis, remains a challenge. Novel therapies comprising a combination of conventional and novel promising treatments are anticipated to be definitive treatments for metastasized and/or recurrent patients with GTNs.

A Potential Therapy Using Engineered Stem Cells Prevented Malignant Melanoma in Cellular and Xenograft Mouse Models

PURPOSE

In the present study, human neural stem cells (hNSCs) with tumor-tropic behavior were used as drug delivery vehicle to selectively target melanoma. A hNSC line (HB1.F3) was transduced into two types: one expressed only the cytosine deaminase (CD) gene (HB1.F3. CD) and the other expressed both CD and human interferon-β (IFN-β) genes (HB1.F3.CD. IFN-β).

Materials and Methods

This study verified the tumor-tropic migratory competence of engineered hNSCs on melanoma (A375SM) using a modified Boyden chamber assay in vitro and CM-DiI staining in vivo. The antitumor effect of HB1.F3.CD and HB1.F3.CD.IFN-β on melanoma was also confirmed using an MTT assay in vitro and xenograft mouse models.

RESULTS

A secreted form of IFN-β from the HB1.F3.CD.IFN-β cells modified the epithelial-mesenchymal transition (EMT) process and metastasis of melanoma. 5-Fluorouracil treatment also accelerated the expression of the pro-apoptotic protein BAX and decelerated the expression of the anti-apoptotic protein Bcl-xL on melanoma cell line.

CONCLUSION

Our results illustrate that engineered hNSCs prevented malignant melanoma cells from proliferating in the presence of the prodrug, and the form that secreted IFN-β intervened in the EMT process and melanoma metastasis. Hence, neural stem cell-directed enzyme/prodrug therapy is a plausible treatment for malignant melanoma.

Cancer-Specific Inhibitory Effects of Genetically Engineered Stem Cells Expressing Cytosine Deaminase and Interferon-β Against Choriocarcinoma in Xenografted Metastatic Mouse Models

Cancer treatments using stem cells expressing therapeutic genes have been identified for various types of cancers. In this study, we investigated inhibitory effects of HB1.F3.CD and HB1.F3.CD.IFN-β cells expressing Escherichia coli cytosine deaminase (CD) and human interferon-β (IFN-β) genes in intravenously (i.v.) injected mice with a metastasis model. In this treatment, pro-drug 5-fluorocytosine (5-FC) is converted to cytotoxic drug 5-fluorouracil by hNSCs expressing the CD gene, which inhibits DNA synthesis in cancer cells. Moreover, IFN-β induces apoptosis and reduces the growth of cancer cells. Upon MTT assay, proliferation of choriocarcinoma (JEG-3) cells decreased when co-cultured with hNSCs expressing CD and IFN-β genes. To confirm the cancer-tropic effect of these stem cells, chemoattractant factors (VEGF, CXCR4, and C-kit) secreted from JEG-3 cells were identified by polymerase chain reaction. hNSCs migrate toward JEG-3 cells due to ligand-receptor interactions of these factors. Accordingly, the migration capability of hNSCs toward JEG-3 cells was confirmed using an in vitro Trans-well assay, in vivo subcutaneously (s.c.) injected mice groups (xenograft model), and metastasis model. Intravenously injected hNSCs migrated freely to other organs when compared to s.c. injected hNSCs. Thus, we confirmed the inhibition of lung and ovarian metastasis of choriocarcinoma by i.v. injected HB1.F3.CD or HB1.F3.CD.IFN-β cells in the presence of 5-FC. Treatment of these stem cells also increased the survival rates of mice. In conclusion, this study showed that metastatic cancer was diminished by genetically engineered hNSCs and noncytotoxic drug 5-FC. This is the first report of the therapeutic potential of i.v. injected hNSCs in a metastasis model; therefore, the results indicate that this stem cell therapy can be used as an alternative novel tool to treat metastatic choriocarcinoma.

Current treatments for advanced melanoma and introduction of a promising novel gene therapy for melanoma (Review)

Metastatic melanoma is a fatal form of skin cancer that has a tendency to proliferate more rapidly than any other solid tumor. Since 2010, treatment options for metastatic melanoma have been developed including chemotherapies, checkpoint inhibition immunotherapies, e.g., anti‑cytotoxic T‑lymphocyte antigen‑4 (CTLA‑4) and anti‑programmed death‑1 (PD‑1), and molecular-targeted therapies, e.g., BRAF and MEK inhibitors. These treatments have shown not only high response rates yet also side‑effects and limitations. Notwithstanding its limitations, stem cell therapy has emerged as a new auspicious therapy for various tumor types. Since stem cells possess the ability to serve as a novel vehicle for delivering therapeutic or suicide genes to primary or metastatic cancer sites, these cells can function as part of gene‑directed enzyme prodrug therapy (GDEPT). This review focuses on introducing engineered neural stem cells (NSCs), which have tumor‑tropic behavior that allows NSCs to selectively approach primary and invasive tumor foci, as a potential gene therapy for melanoma. Therapy using engineered NSCs with cytotoxic agents resulted in markedly reduced tumor volumes and significantly prolonged survival rates in preclinical models of various tumor types. This review elucidates current treatment options for metastatic melanoma and introduces a promising NSC therapy.