Surface expression of anti-CD3scfv stimulates locoregional immunotherapy against hepatocellular carcinoma depending on the E1A-engineered human umbilical cord mesenchymal stem cells

Harnessing adenovirus in cancer immunotherapy: evoking cellular immunity and targeting delivery in cell-specific manner

Recombinant adenovirus (rAd) regimens, including replication-competent oncolytic adenovirus (OAV) and replication-deficient adenovirus, have been identified as potential cancer therapeutics. OAV presents advantages such as selective replication, oncolytic efficacy, and tumor microenvironment (TME) remodeling. In this perspective, the principles and advancements in developing OAV toolkits are reviewed. The burgeoning rAd may dictate efficacy of conventional cancer therapies as well as cancer immunotherapies, including cancer vaccines, synergy with adoptive cell therapy (ACT), and TME reshaping. Concurrently, we explored the potential of rAd hitchhiking to adoptive immune cells or stem cells, highlighting how this approach facilitates synergistic interactions between rAd and cellular therapeutics at tumor sites. Results from preclinical and clinical trials in which immune and stem cells were infected with rAd have been used to address significant oncological challenges, such as postsurgical residual tumor tissue and metastatic tissue. Briefly, rAd can eradicate tumors through various mechanisms, resulting from tumor immunogenicity, reprogramming of the TME, enhancement of cellular immunity, and effective tumor targeting. In this context, we argue that rAd holds immense potential for enhancing cellular immunity and synergistically improving antitumor effects in combination with novel cancer immunotherapies.

Systemic administration of mesenchymal stem cells loaded with a novel oncolytic adenovirus carrying a bispecific T cell engager against hepatocellular carcinoma

We previously established a hepatocellular carcinoma (HCC) targeting system of conditionally replicative adenovirus (CRAd) delivered by human umbilical cord-derived mesenchymal stem cells (HUMSCs). However, this system needed to be developed further to enhance the antitumor effect and overcome the limitations caused by the alpha-fetoprotein (AFP) heterogeneity of HCC. In this study, a bispecific T cell engager (BiTE) targeting programmed death ligand 1 controlled by the human telomerase reverse transcriptase promoter was armed on the CRAd of the old system. It was demonstrated on orthotopic transplantation model mice that the new system had a better anti-tumor effect with no more damage to extrahepatic organs and less liver injury, and the infiltration and activation of T cells were significantly enhanced in the tumor tissues of the model mice treated with the new system. Importantly, we confirmed that the new system eliminated the AFP-negative cells on AFP heterogeneous tumor models efficiently. Conclusion: Compared with the old system, the new system provided a more effective and safer strategy against HCC.

Mesenchymal stem cells-based therapy in liver diseases

Multiple immune cells and their products in the liver together form a complex and unique immune microenvironment, and preclinical models have demonstrated the importance of imbalances in the hepatic immune microenvironment in liver inflammatory diseases and immunocompromised liver diseases. Various immunotherapies have been attempted to modulate the hepatic immune microenvironment for the purpose of treating liver diseases. Mesenchymal stem cells (MSCs) have a comprehensive and plastic immunomodulatory capacity. On the one hand, they have been tried for the treatment of inflammatory liver diseases because of their excellent immunosuppressive capacity; On the other hand, MSCs have immune-enhancing properties in immunocompromised settings and can be modified into cellular carriers for targeted transport of immune enhancers by genetic modification, physical and chemical loading, and thus they are also used in the treatment of immunocompromised liver diseases such as chronic viral infections and hepatocellular carcinoma. In this review, we discuss the immunological basis and recent strategies of MSCs for the treatment of the aforementioned liver diseases. Specifically, we update the immune microenvironment of the liver and summarize the distinct mechanisms of immune microenvironment imbalance in inflammatory diseases and immunocompromised liver diseases, and how MSCs can fully exploit their immunotherapeutic role in liver diseases with both immune imbalance patterns.

Mesenchymal stem cell therapy for liver disease: full of chances and challenges

Liver disease is a major health problem that endangers human health worldwide. Currently, whole organ allograft transplantation is the gold standard for the treatment of end-stage liver disease. A shortage of suitable organs, high costs and surgical complications limit the application of liver transplantation. Mesenchymal stem cell therapy has been considered as a promising alternative approach for end-stage liver disease. Some clinical trials have confirmed the effectiveness of MSC therapy for liver disease, but its application has not been promoted and approved. There are still many issues that should be solved prior to using MSC therapy in clinical applications. The types of liver disease that are most suitable for MSC application should be determined, and the preparation and engraftment of MSCs should be standardized. These may be bottlenecks that limit the use of MSCs. We investigated 22 completed and several ongoing clinical trials to discuss these questions from a clinical perspective. We also discussed the important mechanisms by which MSCs play a therapeutic role in liver disease. Finally, we also proposed novel prospective approaches that can improve the therapeutic effect of MSCs.

PD-1+ Tim3+ tumor-infiltrating CD8 T cells sustain the potential for IFN-γ production, but lose cytotoxic activity in ovarian cancer

Persistent exposure to tumor antigens results in exhausted tumor-infiltrating T cells (TILs) that express the immune checkpoint molecules, PD-1 and Tim3, and lack anti-tumor immunity. To examine the exhausted status of TILs in ovarian cancer, the potential for cytokine production, proliferation and cytotoxicity by purified PD-1+ Tim3+ CD8 TILs was assessed. The production of IFN-γ and TNF-α by PD-1+ Tim3+ CD8 TILs remained the same in an intracellular cytokine staining assay and was higher in a cytokine catch assay than that by PD-1- Tim3- and PD-1+ Tim3- CD8 TILs. %Ki67+ was higher in PD-1+ Tim3+ CD8 TILs than in PD-1- Tim3- CD8 TILs. However, patients with high PD-1+ Tim3+ CD8 TILs had a poor prognosis. The potential for cytotoxicity was then examined. %Perforin+ and %granzyme B+ were lower in PD-1+ Tim3+ CD8 TILs than in PD-1- Tim3- and PD-1+ Tim3- CD8 TILs. To observe the potential for direct cytotoxicity by T cells, a target cell line expressing membrane-bound anti-CD3scFv was newly established and a cytotoxic assay targeting these cells was performed. The cytotoxicity of PD-1+ Tim3+ CD8 TILs was significantly lower than that of PD-1- Tim3- and PD-1+ Tim3- CD8 TILs. Even though PD-1+ Tim3+ CD8 TILs in ovarian cancer showed a sustained potential for cytokine production and proliferation, cytotoxicity was markedly impaired, which may contribute to the poor prognosis of patients with ovarian cancer. Among the impaired functions of exhausted TILs, cytotoxicity may be an essential target for cancer immunotherapy.

Engineered stem cells targeting multiple cell surface receptors in tumors

Multiple stem cell types exhibit inherent tropism for cancer, and engineered stem cells have been used as therapeutic agents to specifically target cancer cells. Recently, stem cells have been engineered to target multiple surface receptors on tumor cells, as well as endothelial and immune cells in the tumor microenvironment. In this review, we discuss the rationales and strategies for developing multiple receptor-targeted stem cells, their mechanisms of action, and the promises and challenges they hold as cancer therapeutics.

Oncolytic Adenovirus-A Nova for Gene-Targeted Oncolytic Viral Therapy in HCC

Hepatocellular carcinoma (HCC) is one of the most frequent cancers worldwide, particularly in China. Despite the development of HCC treatment strategies, the survival rate remains unpleasant. Gene-targeted oncolytic viral therapy (GTOVT) is an emerging treatment modality-a kind of cancer-targeted therapy-which creates viral vectors armed with anti-cancer genes. The adenovirus is a promising agent for GAOVT due to its many advantages. In spite of the oncolytic adenovirus itself, the host immune response is the determining factor for the anti-cancer efficacy. In this review, we have summarized recent developments in oncolytic adenovirus engineering and the development of novel therapeutic genes utilized in HCC treatment. Furthermore, the diversified roles the immune response plays in oncolytic adenovirus therapy and recent attempts to modulate immune responses to enhance the anti-cancer efficacy of oncolytic adenovirus have been discussed.

Bispecific CD3-HAC carried by E1A-engineered mesenchymal stromal cells against metastatic breast cancer by blocking PD-L1 and activating T cells

Background

PD-1/PD-L1 blockade can confer durable benefits in the treatment of metastatic cancers, but the response rate remains modest and potential adverse effects occur sometimes. Concentrating immunotherapeutic agents at the site of disease was believed to break local immune tolerance and reduce systemic toxicity. E1A-engineered mesenchymal stromal cell (MSC.E1A) was an attractive transfer system that preferentially homing and treating cancer metastasis, through which the tumor cells were modified by locally replicated adenoviruses to release CD3-HAC, a bifunctional fusion protein that anti-CD3 scfv linked with high-affinity consensus (HAC) PD-1. Subsequently, CD3-HAC, wbich was bound on PD-L1-positive breast cancer cells, recruited T cells to exhibit a potent antitumor immunity incombination with immune checkpoint blockade.

Methods

We constructed the CD3-HAC gene driven by human telomerase reverse transcriptase (hTERT) promoter into an adenoviral vector and the E1A gene into the lentiviral vector. The homing property of MSCs in vivo was analyzed with firefly luciferase-labeled MSCs (MSC.Luc) by bioluminescent imaging (BLI). The cytotoxicity of T cells induced by CD3-HAC towards PD-L1-positive cells was detected in vitro and in vivo in combination with 5-FU.

Results

Our data suggest that CD3-HAC could specifically bind to PD-L1-positive tumor cells and induce lymphocyte-mediated lysis effectively both in vitro and in vivo. The intervention with HAC diminished the effects of PD-1/PD-L1 axis on T cells exposed to MDA-MB-231 cells and increased lymphocytes activation. MSCs infected by AdCD3-HAC followed by LentiR.E1A could specially migrate to metastasis of breast cancer and produce adenoviruses in the tumor sites. Furthermore, treatment with MSC.CD3-HAC.E1A in combination with 5-FU significantly inhibited the tumor growth in mice.

Conclusions

This adenovirus-loaded MSC.E1A system provides a promising strategy for the identification and elimination of metastasis with locally released immuno-modulator.

Electronic supplementary material

The online version of this article (10.1186/s13045-019-0723-8) contains supplementary material, which is available to authorized users.

Multipotent mesenchymal stromal cells play critical roles in hepatocellular carcinoma initiation, progression and therapy

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, with high morbidity, relapse and mortality rates. Multipotent mesenchymal stromal cells (MSCs) can be recruited to and become integral components of the HCC microenvironment and can influence tumor progression. This review discusses MSC migration to liver fibrosis and the HCC microenvironment, MSC involvement in HCC initiation and progression and the widespread application of MSCs in HCC-targeted therapy, thus clarifying the critical roles of MSCs in HCC.