Karianne Giller Fleten

Appendiceal adenocarcinomas (AA) are a rare and heterogeneous mix of tumors for which few preclinical models exist. The rarity of AA has made performing prospective clinical trials difficult, which has partly contributed to AA remaining an orphan disease with no chemotherapeutic agents approved by the FDA for its treatment. AA has a unique biology in which it frequently forms diffuse peritoneal metastases but almost never spreads via a hematogenous route and rarely spreads to lymphatics. Given the localization of AA to the peritoneal space, intraperitoneal delivery of chemotherapy could be an effective treatment strategy. Here, we tested the efficacy of paclitaxel given by intraperitoneal administration using three orthotopic patient-derived xenograft (PDX) models of AA established in immunodeficient NSG mice. Weekly intraperitoneal paclitaxel treatment dramatically reduced AA tumor growth in all three PDX models. Comparing the safety and efficacy of intravenous with intraperitoneal administration, intraperitoneal delivery of paclitaxel was more effective, with reduced systemic side effects in mice. Given the established safety record of intraperitoneal paclitaxel in gastric and ovarian cancers, and lack of effective chemotherapeutics for AA, these data showing the activity of intraperitoneal paclitaxel in orthotopic PDX models of mucinous AA support the evaluation of intraperitoneal paclitaxel in a prospective clinical trial.Significance:The activity and safety of intraperitoneal paclitaxel in orthotopic PDX models of mucinous appendiceal adenocarcinoma supports the evaluation of intraperitoneal paclitaxel in a prospective clinical trial of this rare tumor type.

Background: Hyperthermic intraperitoneal chemotherapy (HIPEC) following cytoreductive surgery is a potentially curative treatment for patients with peritoneal metastases. Currently, there is no standardized protocol for performing HIPEC and there is large variation in the key parameters. In vivo models can be a valuable tool to better understand the impact of these parameters and how to improve this treatment strategy. Methods: Peritoneal tumors were established in immunodeficient mice by intraperitoneal injection of the high-grade serous human ovarian cancer cell line B76. Thirty-minute perfusion with cisplatin or mitomycin C at 37 or 41 °C was performed 4 days later. Treatment efficacy was assessed by measuring bioluminescence and overall survival. Results: We successfully established a closed peritoneal chemotherapy perfusion model in mice bearing peritoneal metastases. Perfusion with cisplatin and mitomycin C significantly inhibited tumor growth and increased overall survival by 38–48%. The addition of hyperthermia did not improve survival, although a clear synergistic effect with hyperthermia was observed in vitro for both drugs. Conclusion: The results suggest that intraperitoneal perfusion of cisplatin and mitomycin C can be a valuable adjuvant to cytoreductive surgery, while the addition of moderate hyperthermia did not improve efficacy. Additional studies investigating long-term outcome are necessary to determine the impact of hyperthermia as a component of the HIPEC procedure.

Activated RAS is a common driver of cancer that was considered undruggable for decades. Recent advances have enabled the development of RAS inhibitors, but the efficacy of these inhibitors remains limited by resistance. In this study, we developed a pan-RAS inhibitor, ADT-007, (Z)-2-(5-fluoro-1-(4-hydroxy-3,5-dimethoxybenzylidene)-2-methyl-1H-inden-3-yl)-N-(furan-2-ylmethyl)acetamide, that binds nucleotide-free RAS to block GTP activation of effector interactions and MAPK/AKT signaling, resulting in mitotic arrest and apoptosis. ADT-007 potently inhibited the growth of RAS-mutant cancer cells irrespective of the RAS mutation or isozyme. Wild-type RAS (RASWT) cancer cells with GTP-activated RAS from upstream mutations were equally sensitive. Conversely, RASWT cancer cells harboring downstream BRAF mutations and normal cells were essentially insensitive to ADT-007. Sensitivity of cancer cells to ADT-007 required activated RAS and dependence on RAS for proliferation, whereas insensitivity was attributed to metabolic deactivation by UDP-glucuronosyltransferases that were expressed in RASWT and normal cells but repressed in RAS-mutant cancer cells. ADT-007 displayed unique advantages over KRAS mutant-specific, pan-KRAS, and pan-RAS inhibitors that could impact in vivo antitumor efficacy by escaping compensatory mechanisms that lead to resistance. Local administration of ADT-007 showed robust antitumor activity in syngeneic immunocompetent and xenogeneic immune-deficient mouse models of colorectal and pancreatic cancers. The antitumor activity of ADT-007 was associated with the suppression of MAPK signaling and activation of innate and adaptive immunity in the tumor immune microenvironment. Oral administration of ADT-007 prodrug also inhibited tumor growth. Thus, ADT-007 has the potential to address the complex RAS mutational landscape of many human cancers and to improve treatment of RAS-driven tumors. Significance: ADT-007, a first-in-class pan-RAS inhibitor, has unique selectivity for cancer cells with mutant RAS or activated RAS protein and the capability to circumvent resistance to suppress tumor growth, supporting further development of ADT-007 analogs.

Appendiceal adenocarcinomas (AAs) are a rare and heterogeneous mix of tumors for which few preclinical models exist. The rarity of AA has made performing prospective clinical trials difficult, which has partly contributed to AA remaining an orphan disease with no chemotherapeutic agents approved by the FDA for its treatment. AA has a unique biology in which it frequently forms diffuse peritoneal metastases but almost never spreads via a hematogenous route and rarely spreads to lymphatics. Given the localization of AA to the peritoneal space, intraperitoneal (IP) delivery of chemotherapy could be an effective treatment strategy. Here, we tested the efficacy of paclitaxel given by IP administration using three orthotopic patient-derived xenograft (PDX) models of AA established in immunodeficient NSG mice. Weekly IP paclitaxel treatment dramatically reduced AA tumor growth in all three PDX models. Comparing the safety and efficacy of intravenous (IV) to IP administration, IP delivery of paclitaxel was more effective with reduced systemic side effects in mice. Given the established safety record of IP paclitaxel in gastric and ovarian cancers, and lack of effective chemotherapeutics for AA, these data showing the activity of IP paclitaxel in orthotopic PDX models of mucinous AA support the evaluation of IP paclitaxel in a prospective clinical trial.

Appendiceal adenocarcinomas (AA) are a rare and heterogeneous mix of tumors for which few preclinical models exist. The rarity of AA has made performing prospective clinical trials difficult, which has partly contributed to AA remaining an orphan disease with no chemotherapeutic agents approved by the FDA for its treatment. AA has a unique biology in which it frequently forms diffuse peritoneal metastases but almost never spreads via a hematogenous route and rarely spreads to lymphatics. Given the localization of AA to the peritoneal space, intraperitoneal delivery of chemotherapy could be an effective treatment strategy. Here, we tested the efficacy of paclitaxel given by intraperitoneal administration using three orthotopic patient-derived xenograft (PDX) models of AA established in immunodeficient NSG mice. Weekly intraperitoneal paclitaxel treatment dramatically reduced AA tumor growth in all three PDX models. Comparing the safety and efficacy of intravenous with intraperitoneal administration, intraperitoneal delivery of paclitaxel was more effective, with reduced systemic side effects in mice. Given the established safety record of intraperitoneal paclitaxel in gastric and ovarian cancers, and lack of effective chemotherapeutics for AA, these data showing the activity of intraperitoneal paclitaxel in orthotopic PDX models of mucinous AA support the evaluation of intraperitoneal paclitaxel in a prospective clinical trial.Significance:The activity and safety of intraperitoneal paclitaxel in orthotopic PDX models of mucinous appendiceal adenocarcinoma supports the evaluation of intraperitoneal paclitaxel in a prospective clinical trial of this rare tumor type.

Appendiceal adenocarcinomas (AA) are a rare and heterogeneous mix of tumors for which few preclinical models exist. The rarity of AA has made performing prospective clinical trials difficult, which has partly contributed to AA remaining an orphan disease with no chemotherapeutic agents approved by the FDA for its treatment. AA has a unique biology in which it frequently forms diffuse peritoneal metastases but almost never spreads via a hematogenous route and rarely spreads to lymphatics. Given the localization of AA to the peritoneal space, intraperitoneal delivery of chemotherapy could be an effective treatment strategy. Here, we tested the efficacy of paclitaxel given by intraperitoneal administration using three orthotopic patient-derived xenograft (PDX) models of AA established in immunodeficient NSG mice. Weekly intraperitoneal paclitaxel treatment dramatically reduced AA tumor growth in all three PDX models. Comparing the safety and efficacy of intravenous with intraperitoneal administration, intraperitoneal delivery of paclitaxel was more effective, with reduced systemic side effects in mice. Given the established safety record of intraperitoneal paclitaxel in gastric and ovarian cancers, and lack of effective chemotherapeutics for AA, these data showing the activity of intraperitoneal paclitaxel in orthotopic PDX models of mucinous AA support the evaluation of intraperitoneal paclitaxel in a prospective clinical trial. Significance: The activity and safety of intraperitoneal paclitaxel in orthotopic PDX models of mucinous appendiceal adenocarcinoma supports the evaluation of intraperitoneal paclitaxel in a prospective clinical trial of this rare tumor type.