Long-term activation of anti-tumor immunity in pancreatic cancer by a p53-expressing telomerase-specific oncolytic adenovirus.

BACKGROUND: Pancreatic cancer is an aggressive, immunologically "cold" tumor. Oncolytic virotherapy is a promising treatment to overcome this problem. We developed a telomerase-specific oncolytic adenovirus armed with p53 gene (OBP-702). METHODS: We investigated the efficacy of OBP-702 for pancreatic cancer, focusing on its long-term effects via long-lived memory CD8 + T cells including tissue-resident memory T cells (TRMs) and effector memory T cells (TEMs) differentiated from effector memory precursor cells (TEMps). RESULTS: First, in vitro, OBP-702 significantly induced adenosine triphosphate (ATP), which is important for memory T cell establishment. Next, in vivo, OBP-702 local treatment to murine pancreatic PAN02 tumors increased TEMps via ATP induction from tumors and IL-15Rα induction from macrophages, leading to TRM and TEM induction. Activation of these memory T cells by OBP-702 was also maintained in combination with gemcitabine+nab-paclitaxel (GN) in a PAN02 bilateral tumor model, and GN + OBP-702 showed significant anti-tumor effects and increased TRMs in OBP-702-uninjected tumors. Finally, in a neoadjuvant model, in which PAN02 cells were re-inoculated after resection of treated-PAN02 tumors, GN + OBP-702 provided long-term anti-tumor effects even after tumor resection. CONCLUSION: OBP-702 can be a long-term immunostimulant with sustained anti-tumor effects on immunologically cold pancreatic cancer.

Internal hernia caused by exposed structures after laparoscopic lateral lymph node dissection for rectal cancer: A case report.

Internal hernias secondary to exposed structures after lateral lymph node dissection (LLND) for rectal cancer are rare. A 53-year-old man who underwent laparoscopic ultra-low anterior resection and bilateral LND presented to our emergency department with sudden-onset severe abdominal pain and vomiting. Computed tomography demonstrated a closed loop obstruction of the intestine in the right lateral pelvic cavity and a significantly dilated small bowel in the abdominal cavity. Laparoscopic surgery revealed small bowel migration into the space between the right ureter and umbilical artery. The herniated bowel was laparoscopically reduced, and the small bowel exhibited no ischemic changes. Meanwhile, the hernial orifice was left unrepaired. The patient was discharged on the seventh postoperative day without complications. An internal hernia caused by exposed structures after lymphadenectomy should be a differential diagnosis in patients who have undergone LLND for rectal cancer and then present with severe abdominal pain and vomiting.

Local oncolytic adenovirotherapy produces an abscopal effect via tumor-derived extracellular vesicles.

Extracellular vesicles (EVs) play important roles in various intercellular communication processes. The abscopal effect is an interesting phenomenon in cancer treatment, in which immune activation is generally considered a main factor. We previously developed a telomerase-specific oncolytic adenovirus, Telomelysin (OBP-301), and occasionally observed therapeutic effects on distal tumors after local treatment in immunodeficient mice. In this study, we hypothesized that EVs may be involved in the abscopal effect of OBP-301. EVs isolated from the supernatant of HCT116 human colon carcinoma cells treated with OBP-301 were confirmed to contain OBP-301, and they showed cytotoxic activity (apoptosis and autophagy) similar to OBP-301. In bilateral subcutaneous HCT116 and CT26 tumor models, intratumoral administration of OBP-301 produced potent antitumor effects on tumors that were not directly treated with OBP-301, involving direct mediation by tumor-derived EVs containing OBP-301. This indicates that immune activation is not the main factor in this abscopal effect. Moreover, tumor-derived EVs exhibited high tumor tropism in orthotopic HCT116 rectal tumors, in which adenovirus E1A and adenovirus type 5 proteins were observed in metastatic liver tumors after localized rectal tumor treatment. In conclusion, local treatment with OBP-301 has the potential to produce abscopal effects via tumor-derived EVs.

Effect of the disulfide isomerase PDIa4 on the antibody production of Chinese hamster ovary cells.

Therapeutic monoclonal antibodies recognize and bind specific molecules on the surface of target cells, stimulating the immune system, which can attack these targeted cells. These antibodies are produced by mammalian cells, including Chinese hamster ovary (CHO) cells, because the formation of antibodies requires complicated posttranslational modifications, including peptidyl-prolyl cis/trans isomerization, disulfide bond formation, and glycosylation. Currently, it is thought that the efficient production of secretory proteins is limited by posttranslational processes. The ER is the biosynthesis site of all secreted and membrane proteins. The accumulation of unfolded proteins in the ER causes the ER stress response. During the ER stress state, various molecular chaperones are expressed to prevent proteins from the aggregate formation. The molecular chaperone involved in ER stress likely plays an essential role in the production of secretory proteins. The purpose of this study was to improve the production of monoclonal antibodies by cells. We elucidated the function of ER chaperones in the production of a monoclonal antibody. First, we quantitatively measured the mRNA expression levels of protein disulfide-isomerase family members. In CHO HcD6 cells treated with tunicamycin, the expression level of pdia4 was significantly increased. Second, we investigated the relationship between PDIa4 and antibody productivity in pdia4-knockdown cells. Both a decrease in the amount of secreted antibody and the accumulation of immature antibodies inside the cells were observed. Recombinant PDIa4 was able to refold the antibodies and Fabs. These results indicate that PDIa4 affects the production of monoclonal antibodies by catalyzing disulfide bond formation in these antibodies in CHO cells.

Immune Modulation by Telomerase-Specific Oncolytic Adenovirus Synergistically Enhances Antitumor Efficacy with Anti-PD1 Antibody.

The clinical benefit of monotherapy involving immune checkpoint inhibitors (ICIs) such as anti-programmed death-1 antibody (PD-1 Ab) is limited to small populations. We previously developed a telomerase-specific oncolytic adenovirus, Telomelysin (OBP-301), the safety of which was confirmed in a phase I clinical study. Here, we examined the potential of OBP-502, an OBP-301 variant, as an agent for inducing immunogenic cell death (ICD) and synergistically enhancing the efficacy of OBP-502 with PD-1 Ab using CT26 murine colon cancer and PAN02 murine pancreatic cancer cell lines. OBP-502 induced the release of ICD molecules such as adenosine triphosphate (ATP) and high-mobility group box protein 1 (HMGB1) from CT26 and PAN02 cells, leading to recruitment of CD8-positive lymphocytes and inhibition of Foxp3-positive lymphocyte infiltration into tumors. Combination therapy involving OBP-502 intratumoral administration and PD-1 Ab systemic administration significantly suppressed the growth of not only OBP-502-treated tumors but also tumors not treated with OBP-502 (so-called abscopal effect) in CT26 and PAN02 bilateral subcutaneous tumor models, in which active recruitment of CD8-positve lymphocytes was observed even in tumors not treated with OBP-502. This combined efficacy was similar to that observed in a CT26 rectal orthotopic tumor model involving liver metastases. In conclusion, telomerase-specific oncolytic adenoviruses are promising candidates for combined therapies with ICIs.

Delayed hydronephrosis due to retroperitoneal hematoma after a seatbelt injury: A case report.

RATIONALE: Hydronephrosis caused by retroperitoneal hematoma after a seatbelt injury is a unique clinical entity. PATIENT CONCERNS: A 21-year-old man, who had been wearing a seatbelt, was brought to our hospital after a motor vehicle collision, complaining of abdominal pain. Computed tomography (CT) revealed retroperitoneal hematoma in the upper pelvic region. Since he was hemodynamically stable throughout admission, he was managed conservatively. Seventeen days after initial discharge, the patient revisited our emergency department due to right back pain. DIAGNOSES: CT scans indicated retroperitoneal hematoma growth resulting in hydronephrosis of the right kidney. INTERVENTIONS: Laparoscopic drainage of the retroperitoneal hematoma was successfully performed. OUTCOMES: His symptoms resolved after the surgery. Follow-up CT scans three months later demonstrated complete resolution of the hydronephrosis and retroperitoneal hematoma. LESSONS: Our case highlights a patient with delayed hydronephrosis because of retroperitoneal hematoma expansion after a seatbelt injury.

Intramucosal Signet Ring Cell Gastric Cancer Diagnosed 15 Months after the Initial Endoscopic Examination.

The size and shape of intramucosal signet ring gastric cancer in this case remained endoscopically unchanged for 15 months. Laparoscopy-assisted distal gastrectomy was performed, and immunohistochemical analysis revealed Ki-67 and p53 mutations to be negative in this case. Signet ring gastric cancer has long been thought to confer a worse prognosis than other forms of gastric cancer; however, our case did not progress to advanced gastric cancer for 15 months.