BRCA2 결손 마우스 유래 3-D 췌장 오거노이드의 염색체 불안정성 분석

Abstract

Pancreatic cancer remains to be one of the most lethal diseases despite extensive researches. While essential genes responsible for driving pancreatic cancer were revealed, such as K-Ras or Brca2, molecular mechanism to drive pancreatic cancer is to be elucidated. To unveil molecular mechanism about how Brca2 deficiency is related to the development of pancreatic cancer, I have utilized mouse models and 3-D pancreatic organoid culture throughout this study. Brca2 is tumor-suppressor gene that functions in DNA repair, telomere homeostasis and mitotic checkpoint. During mitosis, it mediates the acetylation of BubR1 with PCAF, thus reinforces spindle assembly checkpoint and prevents chromosome instability. In this study, BubR1K243R/+ acetylation deficient mouse model were crossed with K-RasG12D/+

Pdx1-CRE mouse, to assess how chromosome instability can affect the development of pancreatic cancer. Surprisingly, BubR1K243R/+

K-RasG12D/+

Pdx1-CRE mice exhibited expedited tumor growth with shortened life span compared to KRasG12D/+

Pdx1-CRE mice. Analysis of mitotic progression with Mouse embryonic fibroblast implied that mitotic progression was aberrated in the existence of BubR1 acetylation deficiency and oncogenic K-Ras mutation. As well-known tumor-suppressor gene, Brca2 mutation is the highest risk factor of familiar pancreatic cancer and also frequently found in spontaneous pancreatic as well. In order to assess how Brca2 depletion can influence on the integrity of telomere in the context of pancreatic ductal epithelium, I have utilized 3-D organoid culture from Brca2 f11/f11

mTerc-/- mouse model. Unlike other genotypes, Brca2 f11/f11

mTerc-/- showed higher rate of telomere fragility, heterogeneity of length with increased aneuploidy rate. Lastly, I have established pancreatic cancer organoid culture method from patient-derived biopsy sample. This method is envisioned to be the most faithful avatar that reflects individual cancers. A tiny tissue from Endoscopic Ultrasound (EUS)-guided Fine-needle Biopsy (FNB) could be successfully generate pancreatic ductal epithelium, presumably from pancreatic ductal adenocarcinoma and normal ductal tissue. This methodology will be utilized to analyze the patterns of chromosome instability including telomere instability to scrutinize the molecular mechanism of human pancreatic cancer development.