Oncolytic Virus-Mediated Targeting of the ERK Signaling Pathway Inhibits Invasive Propensity in Human Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) cells have an exceptional ability to invade nerves through pronounced crosstalk between nerves and cancer cells; however, the mechanism of PDAC cell invasion remains to be elucidated. Here, we demonstrate the therapeutic potential of telomerase-specific oncolytic adenoviruses, OBP -301 and tumor suppressor p53-armed OBP-702, against human PDAC cells. Highly invasive PDAC cells exhibited higher levels of phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2) expression independent of KRAS expression; ERK1/2 inhibitor or small interfering RNA (siRNA) treatment significantly reduced the migration and invasion of PDAC cells, suggesting that the ERK signaling pathway is associated with the invasiveness of PDAC cells. OBP-702 infection suppressed ERK signaling and inhibited PDAC cell migration and invasion more efficiently than OBP-301. OBP-702 also effectively inhibited PDAC cell invasion even when invasiveness was enhanced by administration of motility stimulators, such as nerve and neurosecretory factors. Moreover, noninvasive whole-body imaging analyses showed that OBP-702 significantly suppressed tumor growth in an orthotopic PDAC xenograft model, although both viruses were equally effective against subcutaneous tumors, suggesting that OBP-702 can influence the orthotopic tumor microenvironment. Our data suggest that oncolytic virus-mediated disruption of ERK signaling is a promising antitumor strategy for attenuating the invasiveness of PDAC cells

Complete response of primary esophageal endocrine cell carcinoma resected after neoadjuvant chemotherapy with docetaxel/cisplatin/5-fluorouracil

　Esophageal endocrine cell carcinoma is extremely rare. We report a case of esophageal endocrine cell carcinoma showing histological complete response to neoadjuvant chemotherapy with docetaxel/cisplatin/5-fluorouracil (DCF). A 66-year-old man had been experiencing epigastralgia, and a type 2 tumor in the thoracic part of esophagus was detected by upper endoscopy. The biopsy showed endocrine cell carcinoma. PET/CT, endoscopy and an esophagogram showed that the patient had a 70-mm scaled type 2 tumor in the middle thoracic esophagus, and they also revealed lymph node metastases (no. 106recR). We diagnosed a cT3cN1cM0 cStage III tumor. With two courses of DCF treatment, both the primary tumor and lymph node metastases showed a partial response. We performed a subtotal esophagectomy with three-field lymph node dissection. The pathological examination of the resected specimens revealed no malignant cells in the esophagus or lymph nodes, and we concluded that the pathological effect of the DCF treatment was Grade 3

A patient with primary malignant melanoma of the esophagus who underwent esophagectomy

　We report the case of a 61-old-man with a primary malignant melanoma of the esophagus, an extremely rare and highly aggressive malignancy. He presented with dysphagia, and we performed an upper gastrointestinal endoscopy that detected a tumor in the thoracic part of the esophagus. The biopsy showed malignant melanoma. PET/CT, endoscopy and an esophagogram showed that a 70-mm scaled type 2+1 tumor in the thoracic esophagus and no metastases. We diagnosed a cT3cN0cM0 cStage II tumor. We then performed a subtotal esophagectomy with two-field lymph node dissection and esophagogastrostomy via a retrosternal route. The pathological examination of the resected specimens confirmed that the type 2+1 tumor was PMME (pT2N0M0 pStage II). We administered six courses of postoperative adjuvant chemotherapy with dacarbazine, and the patient has had no recurrence for 17 months after the surgery

Phase I dose-escalation study of endoscopic intratumoral injection of OBP-301 (Telomelysin) with radiotherapy in oesophageal cancer patients unfit for standard treatments

Purpose: OBP-301 (Telomelysin) is an attenuated type-5 adenovirus that contains the human telomerase reverse transcriptase promoter to regulate viral replication. OBP-301 sensitises human cancer cells to ionising radiation by inhibiting DNA repair, and radiation enhances coxsackievirus and adenovirus receptor-mediated OBP-301 infection on the contrary. We assessed OBP-301 with radiotherapy in oesophageal cancer patients unfit for standard chemoradiation treatments. Methods: A phase I dose-escalation study of OBP-301 with radiotherapy was conducted in 13 histologically confirmed oesophageal cancer patients deemed unfit to undergo surgery or chemotherapy. Study treatment consisted of OBP-301 administration by intratumoural needle injection using a flexible endoscope on days 1, 18 and 32. Radiotherapy was administered concurrently over 6 weeks, beginning on day 4, to a total of 60 Gy. Results: Of the 13 patients, 7, 3 and 3 patients were treated with 10(10), 10(11) and 10(12) virus particles, respectively. Study group comprised 10 males and 3 females, with a median age of 82 years (range, 53-91 years). All patients developed a transient, self-limited lymphopenia. Distribution studies revealed transient virus shedding in the plasma. Eight patients had local complete response (CR); all of them exhibited no pathologically viable malignant cells in biopsy specimens, and 3 patients had a partial response. The objective response rate was 91.7%. The clinical CR rate was 83.3% in stage I and 60.0% in stage II/III. Histopathological examination revealed massive infiltration of CD8 thorn cells and increased PD-L1 expression. Conclusion: Multiple courses of endoscopic intratumoural OBP-301 injection with radiotherapy are feasible and provide clinical benefits in patients with oesophageal cancer unfit for standard treatments. (C) 2021 Elsevier Ltd. All rights reserved