A Novel Molecular Therapy Using Bioengineered Adenovirus for Human Gastrointestinal Cancer

Replication-selective tumor-specific viruses constitute a novel approach for treatment of neoplastic disease. These vectors are designed to induce virus-mediated lysis of tumor cells after selective viral propagation within the tumor. Human telomerase is highly active in more than 85ｵ of primary cancers, regardless of their tissue origins, and its activity correlates closely with human telomerase reverse transcriptase (hTERT) expression. We constructed an attenuated adenovirus 5 vector (Telomelysin, OBP-301), in which the hTERT promoter element drives expression of E1 genes. Since only tumor cells that express telomerase activity would activate this promoter, the hTERT proximal promoter would allow for preferential expression of viral genes in tumor cells, leading to selective viral replication and oncolytic cell death. Lymphatic invasion is a major route for cancer cell dissemination, and adequate treatment of locoregional lymph nodes is required for curative treatment in patients with gastrointestinal tumors. We demonstrated that intratumoral injection of Telomelysin mediates effective in vivo purging of metastatic tumor cells from regional lymph nodes. Moreover, using noninvasive whole-body imaging, we found that intratumoral injection of Telomelysin followed by regional irradiation induces a substantial antitumor effect, resulting from tumor cell-specific radiosensitization, in an orthotopic human esophageal cancer xenograft model. These results illustrate the potential of oncolytic virotherapy as a promising strategy in the management of human gastrointestinal cancer

Ataxia-Telangiectasia Mutated and the Mre11-Rad50-NBS1 Complex:Promising Targets for Radiosensitization

Radiotherapy plays a central part in cancer treatment, and use of radiosensitizing agents can greatly enhance this modality. Although studies have shown that several chemotherapeutic agents have the potential to increase the radiosensitivity of tumor cells, investigators have also studied a number of molecularly targeted agents as radiosensitizers in clinical trials based on reasonably promising preclinical data. Recent intense research into the DNA damage-signaling pathway revealed that ataxia-telangiectasia mutated (ATM) and the Mre11-Rad50-NBS1 (MRN) complex play central roles in DNA repair and cell cycle checkpoints and that these molecules are promising targets for radiosensitization. Researchers recently developed three ATM inhibitors (KU-55933, CGK733, and CP466722) and an MRN complex inhibitor (mirin) and showed that they have great potential as radiosensitizers of tumors in preclinical studies. Additionally, we showed that a telomerase-dependent oncolytic adenovirus that we developed (OBP-301 [telomelysin]) produces profound radiosensitizing effects by inhibiting the MRN complex via the adenoviral E1B55kDa protein. A recent Phase I trial in the United States determined that telomelysin was safe and well tolerated in humans, and this agent is about to be tested in combination with radiotherapy in a clinical trial based on intriguing preclinical data demonstrating that telomelysin and ionizing radiation can potentiate each other. In this review, we highlight the great potential of ATM and MRN complex inhibitors, including telomelysin, as radiosensitizing agents

Multidisciplinary oncolytic virotherapy for gastrointestinal cancer

Replication-selective tumor-specific viruses represent a novel approach for treating neoplastic diseases. These vectors are designed to induce virus-mediated lysis of tumor cells after selective intracellular virus propagation. For targeting cancer cells, the use of tissue- or cell-specific promoters that are expressed in diverse tumor types but silent in normal cells is required. Human telomerase is highly active in more than 85% of primary cancers, regardless of tissue origin, and its activity is closely correlated with human telomerase reverse transcriptase (hTERT) expression. We constructed an attenuated adenovirus 5 vector (telomelysin, OBP-301) in which the hTERT promoter element drives expression of E1 genes. As only tumor cells that express the telomerase can activate this promoter, the hTERT proximal promoter allows for preferential expression of viral genes in tumor cells, leading to selective viral replication and oncolytic cell death. Upon US Food and Drug Administration approval, a phase 1 dose-escalation study of intratumoral injection of telomelysin for various solid tumors has been completed to confirm the safety, tolerability, and feasibility of the agent. Moreover, we found that adenoviral E1B 55-kDa protein in telomelysin inhibits the radiation-induced DNA repair machinery. Thus, tumor cells infected with telomelysin could be rendered sensitive to ionizing radiation. Recently, we assessed the safety and efficacy of intratumoral injection of telomelysin with radiotherapy in esophageal cancer patients not suited for standard treatments. This review highlights some very promising clinical advances in cancer therapeutic technologies using telomerase-specific oncolytic virotherapy

Laparoscopic Surgical Options as a Minimally Invasive Procedure for a Patient With Recurrent Postoperative Pain in Anterior Cutaneous Nerve Entrapment Syndrome: A Case Report

This report presents a case of a 70-year-old woman who developed anterior cutaneous nerve entrapment syndrome (ACNES) three years ago and had an anterior cutaneous neurectomy in the left Th10 region. Postoperatively, the pain had improved entirely, but 10 weeks later, she developed a recurrence in the vicinity of the wound. The anterior intercostal nerve branch (Th10), located between the transversus abdominis and internal oblique muscles, was dissected laparoscopically six months after the initial surgery. There was no re-recurrence of pain for four months postoperatively. The postoperative recurrence of ACNES was refractory to various treatments, including surgical neurectomy, and is often difficult to treat. In cases in which transversus abdominis plane block is effective, laparoscopic neurectomy through an intraperitoneal approach may be effective, and minimally invasive laparoscopic treatment may be an effective surgical option for patients with recurrent and refractory ACNES who have a low pain threshold and are prone to prolonged complaints due to wound pain