Optimization of adenoviral gene transfer in human pluripotent stem cells

Triple-regulated conditionally replicating adenovirus for effective and safer treatment of peritoneal carcinomatosis

There is no effective therapy for peritoneal carcinomatosis derived from gastric cancer. An ideal conditionally replicating adenovirus (CRA) that selectively replicates in and kills cancer cells has not been developed for gastric cancer-derived peritoneal carcinomatosis. Using our platform technology of CRA regulated and treating tumors with multiple factors (m-CRA), we generated two types of survivin-responsive m-CRAs, Surv.m-CRA-CMVp and Surv.m-CRA-CEAp, consisting of E1A downstream of the survivin promoter, and the mutated E1B gene downstream of the human cytomegalovirus immediate early gene enhancer/promoter and carcinoembryonic antigen promoter, respectively. Survivin mRNA was expressed at high and undetectable levels in two gastric cancer cells and eleven normal cells, respectively. Carcinoembryonic antigen was expressed at high and very low levels in MKN-45 gastric cancer and normal PrEC cells, respectively, and was not detected in other cell types. While both Surv.m-CRA-CEAp and Surv.m-CRA-CMVp exhibited potent cytotoxic effects on MKN-45 cells in vitro, Surv.m-CRA-CEAp significantly reduced cytotoxicity to normal cells compared to Surv.m-CRA-CMVp. Control mice that received an intraperitoneal injection of MKN-45 cells gradually lost body weight and died of peritoneal carcinomatosis within 98 days. In contrast, all mice receiving Surv.m-CRA-CEAp or Surv.m-CRA-CMVp-infected MKN-45 cells increased their body weight and survived 120 days. In conclusion, the triple-regulated Surv.m-CRA-CEAp enhances cancer specificity (i.e., safety) without reducing the potent therapeutic effect for carcinoembryonic antigen-positive gastric cancer-derived peritoneal carcinomatosis. The modified E1B promoter strategy of CRA facilitates the development of novel CRAs for the effective and safe treatment of a variety of refractory cancers.

Application Prospect of Induced Pluripotent Stem Cells in Organoids and Cell Therapy

Since its inception, induced pluripotent stem cell (iPSC) technology has been hailed as a powerful tool for comprehending disease etiology and advancing drug screening across various domains. While earlier iPSC-based disease modeling and drug assessment primarily operated at the cellular level, recent years have witnessed a significant shift towards organoid-based investigations. Organoids derived from iPSCs offer distinct advantages, particularly in enabling the observation of disease progression and drug metabolism in an in vivo-like environment, surpassing the capabilities of iPSC-derived cells. Furthermore, iPSC-based cell therapy has emerged as a focal point of clinical interest. In this review, we provide an extensive overview of non-integrative reprogramming methods that have evolved since the inception of iPSC technology. We also deliver a comprehensive examination of iPSC-derived organoids, spanning the realms of the nervous system, cardiovascular system, and oncology, as well as systematically elucidate recent advancements in iPSC-related cell therapies.

Adenovirus Biology, Recombinant Adenovirus, and Adenovirus Usage in Gene Therapy

Gene therapy is currently in the public spotlight. Several gene therapy products, including oncolytic virus (OV), which predominantly replicates in and kills cancer cells, and COVID-19 vaccines have recently been commercialized. Recombinant adenoviruses, including replication-defective adenoviral vector and conditionally replicating adenovirus (CRA; oncolytic adenovirus), have been extensively studied and used in clinical trials for cancer and vaccines. Here, we review the biology of wild-type adenoviruses, the methodological principle for constructing recombinant adenoviruses, therapeutic applications of recombinant adenoviruses, and new technologies in pluripotent stem cell (PSC)-based regenerative medicine. Moreover, this article describes the technology platform for efficient construction of diverse "CRAs that can specifically target tumors with multiple factors" (m-CRAs). This technology allows for modification of four parts in the adenoviral E1 region and the subsequent insertion of a therapeutic gene and promoter to enhance cancer-specific viral replication (i.e., safety) as well as therapeutic effects. The screening study using the m-CRA technology successfully identified survivin-responsive m-CRA (Surv.m-CRA) as among the best m-CRAs, and clinical trials of Surv.m-CRA are underway for patients with cancer. This article also describes new recombinant adenovirus-based technologies for solving issues in PSC-based regenerative medicine.