京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21645号 / 医博第4451号 / 新制||医||1034(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 川口 義弥, 教授 羽賀 博典, 教授 小西 靖彦 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Pancreatic cancer (PC) remains one of the most challenging solid tumors to treat with a high unmet medical need as patients poorly respond to standard-of-care-therapies. Prominent desmoplastic reaction involving cancer-associated fibroblasts (CAFs) and the immune cells in the tumor microenvironment (TME) and their cross-talk play a significant role in tumor immune escape and progression. To identify the key cellular mechanisms induce an immunosuppressive tumor microenvironment, we established 3D co-culture model with pancreatic cancer cells, CAFs, monocyte as well as T cells. Using this model, we analysed the influence of tumor cells and fibroblasts on monocytes and their immune suppressive phenotype. Phenotypic characterization of the monocytes after 3D co-culture with tumor/fibroblast spheroids was performed by analysing the expression of defined cell surface markers and soluble factors. Functionality of these monocytes and their ability to influence T cell phenotype and proliferation was investigated. 3D co-culture of monocytes with pancreatic cancer cells and fibroblasts induced the production of immunosuppressive cytokines which are known to promote polarization of M2 like macrophages and myeloid derived suppressive cells (MDSCs). These co-culture spheroid polarized monocyte derived macrophages (MDMs) were poorly differentiated and had an M2 phenotype. The immunosuppressive function of these co-culture spheroids polarized MDMs was demonstrated by their ability to inhibit autologous CD4+ and CD8+ T cell activation and proliferation in vitro, which we could partially reverse by 3D co-culture spheroid treatment with therapeutic molecules that are able to re-activate spheroid polarized MDMs or block immune suppressive factors such as Arginase-I. In conclusion, we generated a physiologically relevant 3D co-culture model, which can be used as a promising tool to study complex cell-cell interactions between different cell types within the tumor microenvironment and to support drug screening and development. In future, research focused on better understanding of resistance mechanisms to existing cancer immunotherapies will help to develop new therapeutic strategies in order to combat cancer. / Bei Bauchspeicheldrüsenkrebs handelt es sich um eine maligne Tumorerkrankung, deren Behandlung Ärzte noch immer vor große Herausforderungen stellen und die zur dritthäufigsten krebsbedingten Todesursache der westlichen Welt zählt. Desmoplastische Reaktionen im Tumorgewebe sind hierbei ein besonderes Merkmal dieser Erkrankung. Dabei spielen tumor-assoziierte Fibroblasten sowie unterschiedliche Zellen des Immunsystems und deren Interaktionen eine essentielle Rolle hinsichtlich Tumorwachstum und der Herunterregulation des Immunsystems. Um zelluläre Mechanismen, die ein immunsuppressives Tumormilieu induzieren, zu identifizieren, entwickelten wir ein 3D Ko-Kultur Modell mit Bauchspeicheldrüsenkrebszellen, tumor-assoziierten Fibroblasten sowie Monozyten und T-Zellen. Mit Hilfe dieses Modells konnten wir den Einfluss von Tumorzellen und Fibroblasten auf den Phänotyp und das Verhalten von Monozyten untersuchen. Dazu wurden Monozyten in einer 3D Tumorzell/Fibroblasten Ko-Kultur kultiviert und differenziert, um anschließend die Expression definierter Zelloberflächenmarker und löslicher Faktoren zu analysieren. Des Weiteren wurde das Verhalten dieser 3D Ko-Kultur differenzierten myeloiden Zellpopulation sowie ihre Fähigkeit den Phänotyp von T Zellen und deren Proliferation zu beeinflussen untersucht. Die 3D Ko-Kultur der Monozyten zusammen mit den Tumorzellen und den Fibroblasten führten zur Produktion immunsuppressiver Zytokine und Chemokine, wodurch die Differenzierung der Monozyten in M2-ähnliche Makrophagen induziert wurde. Diese durch die 3D Tumorzell/Fibroblasten Sphäroide polarisierten aus Monozyten herangereiften M2-ähnlichen Makrophagen besaßen außerdem immunsuppressive funktionelle Eigenschaften, indem sie in der Lage waren, die Aktivierung und Proliferation von autologen CD4+ und CD8+ T Zellen in vitro zu inhibieren. Die Suppression sowohl der CD4+ als auch der CD8+ T Zellen konnte durch die Behandlung therapeutischer Moleküle, die die Re-Aktivierung der immunsuppressiven 3D Sphäroid polarisierten Makrophagen stimulierten oder suppressive Faktoren wie Arginase-I blockierten, wieder aufgehoben und die T Zell Proliferation teilweise wiederhergestellt werden. Unser etabliertes 3D Ko-Kultur System repräsentiert ein vielversprechendes physiologisch relevantes Modell, welches genutzt werden kann, um Zell-Zell Interaktion und Kommunikation im Tumormilieu zu untersuchen und dadurch die Wirkung von Medikamenten zu verbessern. Ein gezieltes besseres Verständnis von Tumorresistenz Mechanismen gegen bereits bestehende Immun Therapien fördert die Entwicklung neuer therapeutischer Ansätze zur Bekämpfung von Krebs.

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Ataxia Telangiectasia Mutated (ATM) gene helps to repair DNA damage and that increased cancer risks are associated with having a mutation in an ATM gene. ATM gene is newer compared to other known hereditary cancer genes. We present a rare care of 66-year-old female with extensive personal and family history of breast and pancreatic cancer had negative imaging surveillance until recent systemic imaging showed new pancreatic head 2.5x2.5 cm mass. Endoscopic ultrasound confirmed invasion of superior mesenteric vein with near confluence. No regional adenopathy was seen. She was felt to be borderline resectable and neoadjuavant chemotherapy was planned. She had a personal history of right breast cancer diagnosed in 1998 status post lumpectomy and axillary lymph node dissection and adjuvant chemotherapy with CMF regimen x 5 cycles and radiation therapy and endocrine therapy with tamoxifen for 5 years. In 2011 she was also diagnosed with rectal well to moderately differentiated adenocarcinoma status post abdominoperitoneal resection on 3/15/2011, 36 lymph nodes were negative, but the surgical circumferential radial margin was positive. She underwent adjuvant radiation therapy with total dose of 45 Gy. There was recurrence in vaginal and bladder wall adenocarcinoma in 2014 for which patient underwent an anterior exenteration. Pathology felt this was endocervical origin of malignancy and patient received megace therapy for 3 years based on hormone receptor positive status. For new diagnosis of pancreatic adenocarcinoma, she was started on Gemcitabine and Abraxane chemotherapy. Given extensive personal and family history of malignancy, she was referred to genetic counsellor. Hereditary cancers panel at invitae laboratory was positive for a heterozygous pathological variant in the ATM gene deletion (exons 62-63). ATM gene is associated with an increased risk for autosomal dominant breast, pancreatic and prostate cancer. Close relatives (children, siblings, and each parent) have up to a 50% chance of being a carrier of this variant. It is essential for treating physicians to educate patients and family members on the risk for subsequent malignancies.

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal common cancer in the United States: in 2017 there will be around 54,000 new cases and 43,000 patient deaths. (SEER, 2017) The high mortality of PDAC is related to late disease presentation and aggressiveness; nearly 52% of patients present with metastatic disease at the time of diagnosis. (SEER, 2017) Current treatments have marginal improvements on survival, with the most efficacious treatment, gemcitabine and nab-paclitaxel, having a median survival of 12.2 months. (Wu 2018) Failure of current PDAC treatments is attributed to the inefficacy of systemic chemotherapeutics and the development of resistance. (Rahib, 2014) The Dual Endothelin1/Signal PeptideVEGF receptor (DEspR), represents a promising therapeutic target for the treatment of PDAC: it is a highly expressed, specific tumor antigen, which is involved in tumor vasculogenesis and cancer stem cell (CSC) survival. DEspR is a developmentally crucial receptor, responsible for early angiogenesis and neural crest migration, with minimal expression in normal adult tissue. In vitro and in vivo studies of anti-DEspR therapy in PDAC have shown efficacy in decreasing CSC survival, tumor angiogenesis, and improving overall survival in xenograft models of PDAC, with anti-DEspR therapy being a promising candidate for clinical use. Furthermore, anti-DEspR therapy seems to augment chemotherapeutic therapy in vitro and in vivo, suggesting that a DEspR-targeted antibody drug conjugate (ADC) would be highly effective. ADCs are a re-emerging drug class with significant promise. Initial failures of ADCs in clinic were related to poor antigen specificity and failures in drug conjugation chemistry to minimally impact the antibody. To develop our ADC, I have developed a novel method of site-specific conjugation that relies on a novel method of supramolecular assembly. My system employs two specific protein sequences that do not self-interact, and tightly assemble through coulombic and hydrophobic interactions, allowing site-specific, stoichiometric self-assembly. To facilitate stable drug delivery, I have synthesized a novel enzymatically cleavable tyrosine-clickable linker, which prevents drug release prior to tumor delivery. Both further investigation into the efficacy of anti-DEspR therapy, and the development of a stoichiometric, site-specific, stable method for drug loading will provide an advancement in anti-cancer therapy.

BACKGROUND: Pancreatic ductal adenocarcinoma maintains a formidable mortality rate with rising incidence despite extensive research efforts. As of 2021 pancreatic cancer is the third leading cause of cancer-related deaths in the United States despite its incidence representing only 3% of all cancer diagnoses. Given the high mortality rate, research efforts push to improve prognosis by expanding knowledge and tools in the realms of diagnostics, genetics, development of screening modalities, and targeted treatments. Modifications in treatment algorithms have led to only modest improvements in outcome. Current research efforts focus on primary and secondary prevention aimed at modifications of known environmental and hereditary risk factors. Available studies highlight the relationship between relative geography and cancers; however, there is a paucity of research available on the Social Determinants of Health on access to pancreatic cancer care and outcomes. PROPOSED PROJECT: Data will be extracted from the Surveillance, Epidemiology, and End Results (SEER) database and combined with US Census data along with medical record information as relevant over a seven-year period from January 1, 2010, through December 31, 2017. Social Vulnerability Index scores will be derived from the available data as a surrogate for Social Determinant of Health and be assigned to each case of pancreatic cancer from 2010-2017. These scores will be grouped by zip code. Analysis will then be performed to identify the mean stage at time of diagnosis for each zip code. Further analysis will be performed to calculate survival curves for each zip code and cox proportional-hazards will be performed on results to determine statistical significance of SVI with respect to geography. CONCLUSIONS: The proposed study will investigate the impact of geography as a Social Determinant of Health (SDoH) within the United States on the stage at time of diagnosis for pancreatic ductal adenocarcinoma. As a secondary measure, overall survival following diagnosis of pancreatic ductal adenocarcinoma will be examined. SIGNIFICANCE: This study will identify the impact of social determinants of health on geography and correlate the impact on outcomes in pancreatic ductal adenocarcinoma in the United States of America. This study may also identify geographic regions in which the incidence of PDAC is higher than expected which would present a population to investigate for additional screening studies and development of risk prediction models.

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