胰臟癌是一種極具侵襲性的癌症，其發病率幾乎等於其死亡率,而且胰臟癌是目前人類的惡性腫瘤中預後最差的。治療胰臟癌的方法最常見的為手術切除,但由於胰臟癌在早期的症狀病不明顯而且纖維化不顯著，僅有20％的胰臟癌患者有機會進行手術切除，其餘80%的患者是無法治癒的。甚至近年來胰臟癌患者常有藥物阻抗的特性，可能原因為胰臟癌晚期時纖維化已經很嚴重,導致藥物無法順利進入至胰臟病灶區達到治療的效果。近年來有許多研究顯示，腫瘤微環境與腫瘤細胞之間的相互作用在胰臟癌的發展過程中扮演很重要的角色，甚至與胰臟組織纖維化所造成的硬度有關。在機械生物學領域的研究當中，微環境中物理性的改變會影響周邊細胞的行為，進而促進腫瘤發展。胰臟星狀細胞在胰臟癌基質當中扮演很重要的角色，當胰臟星狀細胞活化之後，不僅會大量合成細胞外基質蛋白質造成胰臟纖維化，還會釋出趨化物質及生長因子供腫瘤細胞的生存。然而，胰臟星狀細胞的活化是否會受到由細胞外基質蛋白質組成的不同程度硬化所影響，進而促進胰臟癌的發展仍不清楚。在胰臟癌患者身上，我們同時觀察到纖維化程度、胰臟星狀細胞活化程度以及硬度都是上升的。這些數據顯示細胞外基質硬度和胰臟星狀細胞活化呈現正相關的。在細胞實驗，我們證實隨著硬度增加會促使胰臟星狀細胞活化。經過microarray分析，我們找到ARHGEF28是一個很重要的調節者。隨著硬度增加，ARHGEF28的表現量也跟著上升，當ARHGEF28的表現量被抑制住，在硬的環境下，胰臟星狀細胞仍然呈現不活化態。甚至我們發現硬度影響ARHGEF28的表現量可能是透過FAK/ERK/ETS1這條路徑。在動物實驗當中，為了模擬不同程度的纖維化，我們在KC老鼠身上依不同時間點施打胰臟發炎藥物cerulein，數據顯示細胞外基質硬度和胰臟星狀細胞活化呈現正相關的。另外，有滿多研究顯示慢性胰臟炎和胰臟癌的發展息息相關，會造成胰臟癌有纖維化大多和發炎物質有關係。在慢性胰臟發炎的小鼠胰臟當中，我們觀察到大量的TNF-α表現，TNF-α是一種發炎因子和胰臟星狀細胞的活化有關聯性。接著，我們想去探討TNF-α發炎物質在細胞外基質當中的角色，我們發現發炎物質也會造成胰臟星狀細胞纖維化。總結來說，發炎物質可能是最早期造成胰臟星狀細胞活化的調節者，進一步造成胰臟局部纖維化，纖維化所造成的硬度會又促使周邊不活化胰臟星狀細胞活化，而且可能是透過FAK/ERK/ARHGEF28這條路徑影響胰臟星狀細胞活化，而這麼樣的正回饋會加劇胰臟癌的發展，因此若針對ARHGEF28開發一款新的藥物，抑制ARHGEF28的表現，說不定可以有效控制胰臟癌。

Pancreatic cancer (PC) is an extremely aggressive cancer with an incidence rate that nearly equals its mortality rate and a very unfavorable prognosis. PC has poor prognosis of pancreatic cancer is due to unremarkable fibrosis during early stage of the cancer with limit efficacy therapies. The major therapy for pancreatic cancer is surgery, but only 20% have the opportunity to receive resection. The remaining 80% are unresectable and incurable tumors. Moreover, pancreatic cancer cells have a property of drug-resistant that decreases efficacy of therapies in pancreatic cancer patients because of extreme fibrosis in the last stage of cancer that blocks the delivery of chemotherapy drugs into pancreas tissues completely. Emerging evidence has revealed that the interaction between the tumor microenvironment and tumor cells plays a pivotal role in pancreatic tumorigenesis and is associated with increased tumor tissue rigidity. Research in the field of mechanical biology have shown that altered mechanical force in the microenvironment will affect peripheral cells behavior and then promote tumor progression. Pancreatic stellate cells (PSCs) are a major component of the stroma of pancreatic cancer. When PSCs activation, they not only synthesize extracellular matrix (ECM) protein to cause fibrosis in pancreas but also release cytokine and growth factors to regulate PC cells survival. However, whether PSC activation can be affected by ECM stiffness then promote cancer progression remain unclear. First, we found that fibrosis, PSC activation, and stiffness are increased in pancreatic tumor tissue of pancreatic cancer patients. These data showed ECM stiffness might be positive correlation with PSCs activation. Furthermore, we confirm that ECM stiffness active PSCs activation in vitro. From microarray data, we found that ARHGEF28 plays a key regulator in ECM stiffness-induced PSCs activation. We observed the expression of ARHGEF28 was upregulated in stiffer gel. After knockdown ARHGEF28 in PSCs cultured in stiffer gels, PSCs present quiescent form. Also, FAK/ERK/ETS1 might be a critical pathway to upregulate ARHGEF28 in stiffness-induced PSC activation. In vivo, we create different scales of pancreas fibrosis KrasG12D; Pdx-creTg (KC) mice by treating cerulein for different time. The data revealed that ECM stiffness of pancreas is positively correlated with PSC activation and metaplasia. It is well known that the chronic inflammation promote pancreas metaplasia and neoplastic transformation. In vivo data, we observed that TNF-α, one of inflammatory cytokines may activate PSCs during pancreatic injury, was the most upregulated in pancreatitis mouse model. We next explore the role of inflammatory cytokines in development of ECM stiffness. The results showed that inflammation cytokines may be the early mediators which activate PSCs to result in fibrosis and foster tumorigenesis. In this study, we have proved that ECM stiffness activates PSCs through the possible signaling pathway FAK/ERK/ARHGEF28. Taken together, inflammation cytokines may be the early mediators that activate PSCs to cause fibrosis, and ECM stiffness activate PSCs which is proven in our vitro data. This positive feedback in tumor microenvironment will promote tumor growth. Therefore, by blocking ARHGEF28 of PSCs in pancreatic cancer characteristics sever fibrosis, that will be efficient to control pancreatic cancer progression.

Apte, M. V. and J. S. Wilson (2012). "Dangerous liaisons: pancreatic stellate cells and pancreatic cancer cells." J Gastroenterol Hepatol 27 Suppl 2: 69-74.
Balkwill, F. and A. Mantovani (2001). "Inflammation and cancer: back to Virchow?" Lancet 357(9255): 539-545.
Bilimoria, K. Y., D. J. Bentrem, C. Y. Ko, J. Ritchey, A. K. Stewart, D. P. Winchester and M. S. Talamonti (2007). "Validation of the 6th edition AJCC Pancreatic Cancer Staging System: report from the National Cancer Database." Cancer 110(4): 738-744.
Chen, C. S., M. Mrksich, S. Huang, G. M. Whitesides and D. E. Ingber (1997). "Geometric control of cell life and death." Science 276(5317): 1425-1428.
Engler, A. J., M. A. Griffin, S. Sen, C. G. Bonnemann, H. L. Sweeney and D. E. Discher (2004). "Myotubes differentiate optimally on substrates with tissue-like stiffness: pathological implications for soft or stiff microenvironments." J Cell Biol 166(6): 877-887.
Feig, C., A. Gopinathan, A. Neesse, D. S. Chan, N. Cook and D. A. Tuveson (2012). "The pancreas cancer microenvironment." Clin Cancer Res 18(16): 4266-4276.
Friess, H., X. Z. Guo, B. C. Nan, J. Kleeff and M. W. Buchler (1999). "Growth factors and cytokines in pancreatic carcinogenesis." Ann N Y Acad Sci 880: 110-121.
Georges, P. C. and P. A. Janmey (2005). "Cell type-specific response to growth on soft materials." J Appl Physiol (1985) 98(4): 1547-1553.
Humphrey, J. D., E. R. Dufresne and M. A. Schwartz (2014). "Mechanotransduction and extracellular matrix homeostasis." Nat Rev Mol Cell Biol 15(12): 802-812.
Ilic, M. and I. Ilic (2016). "Epidemiology of pancreatic cancer." World J Gastroenterol 22(44): 9694-9705.
Joyce, J. A. (2005). "Therapeutic targeting of the tumor microenvironment." Cancer Cell 7(6): 513-520.
Junttila, M. R. and F. J. de Sauvage (2013). "Influence of tumour micro-environment heterogeneity on therapeutic response." Nature 501(7467): 346-354.
Kirkegard, J., F. V. Mortensen and D. Cronin-Fenton (2017). "Chronic Pancreatitis and Pancreatic Cancer Risk: A Systematic Review and Meta-analysis." Am J Gastroenterol 112(9): 1366-1372.
Kong, X., T. Sun, F. Kong, Y. Du and Z. Li (2014). "Chronic Pancreatitis and Pancreatic Cancer." Gastrointest Tumors 1(3): 123-134.
L., S. R., M. K. D. and J. Ahmedin (2018). "Cancer statistics, 2018." CA: A Cancer Journal for Clinicians 68(1): 7-30.
Li, X., Q. Ma, Q. Xu, W. Duan, J. Lei and E. Wu (2012). "Targeting the cancer-stroma interaction: a potential approach for pancreatic cancer treatment." Curr Pharm Des 18(17): 2404-2415.
Lindau, D., P. Gielen, M. Kroesen, P. Wesseling and G. J. Adema (2013). "The immunosuppressive tumour network: myeloid-derived suppressor cells, regulatory T cells and natural killer T cells." Immunology 138(2): 105-115.
Lu, P., V. M. Weaver and Z. Werb (2012). "The extracellular matrix: a dynamic niche in cancer progression." J Cell Biol 196(4): 395-406.
Miller, K. D., R. L. Siegel, C. C. Lin, A. B. Mariotto, J. L. Kramer, J. H. Rowland, K. D. Stein, R. Alteri and A. Jemal (2016). "Cancer treatment and survivorship statistics, 2016." CA Cancer J Clin 66(4): 271-289.
Neesse, A., H. Algul, D. A. Tuveson and T. M. Gress (2015). "Stromal biology and therapy in pancreatic cancer: a changing paradigm." Gut 64(9): 1476-1484.
Olive, K. P., M. A. Jacobetz, C. J. Davidson, A. Gopinathan, D. McIntyre, D. Honess, B. Madhu, M. A. Goldgraben, M. E. Caldwell, D. Allard, K. K. Frese, G. Denicola, C. Feig, C. Combs, S. P. Winter, H. Ireland-Zecchini, S. Reichelt, W. J. Howat, A. Chang, M. Dhara, L. Wang, F. Ruckert, R. Grutzmann, C. Pilarsky, K. Izeradjene, S. R. Hingorani, P. Huang, S. E. Davies, W. Plunkett, M. Egorin, R. H. Hruban, N. Whitebread, K. McGovern, J. Adams, C. Iacobuzio-Donahue, J. Griffiths and D. A. Tuveson (2009). "Inhibition of Hedgehog signaling enhances delivery of chemotherapy in a mouse model of pancreatic cancer." Science 324(5933): 1457-1461.
Pandol, S., M. Edderkaoui, I. Gukovsky, A. Lugea and A. Gukovskaya (2009). "Desmoplasia of pancreatic ductal adenocarcinoma." Clin Gastroenterol Hepatol 7(11 Suppl): S44-47.
Pickup, M. W., J. K. Mouw and V. M. Weaver (2014). "The extracellular matrix modulates the hallmarks of cancer." EMBO Rep 15(12): 1243-1253.
Provenzano, P. P. and S. R. Hingorani (2013). "Hyaluronan, fluid pressure, and stromal resistance in pancreas cancer." Br J Cancer 108(1): 1-8.
Quail, D. F. and J. A. Joyce (2013). "Microenvironmental regulation of tumor progression and metastasis." Nat Med 19(11): 1423-1437.
Sherman, M. H., R. T. Yu, D. D. Engle, N. Ding, A. R. Atkins, H. Tiriac, E. A. Collisson, F. Connor, T. Van Dyke, S. Kozlov, P. Martin, T. W. Tseng, D. W. Dawson, T. R. Donahue, A. Masamune, T. Shimosegawa, M. V. Apte, J. S. Wilson, B. Ng, S. L. Lau, J. E. Gunton, G. M. Wahl, T. Hunter, J. A. Drebin, P. J. O'Dwyer, C. Liddle, D. A. Tuveson, M. Downes and R. M. Evans (2014). "Vitamin D receptor-mediated stromal reprogramming suppresses pancreatitis and enhances pancreatic cancer therapy." Cell 159(1): 80-93.
van Horck, F. P., M. R. Ahmadian, L. C. Haeusler, W. H. Moolenaar and O. Kranenburg (2001). "Characterization of p190RhoGEF, a RhoA-specific guanine nucleotide exchange factor that interacts with microtubules." J Biol Chem 276(7): 4948-4956.
Wehr, A. Y., E. E. Furth, V. Sangar, I. A. Blair and K. H. Yu (2011). "Analysis of the human pancreatic stellate cell secreted proteome." Pancreas 40(4): 557-566.
Whatcott, C. J., C. H. Diep, P. Jiang, A. Watanabe, J. LoBello, C. Sima, G. Hostetter, H. M. Shepard, D. D. Von Hoff and H. Han (2015). "Desmoplasia in Primary Tumors and Metastatic Lesions of Pancreatic Cancer." Clin Cancer Res 21(15): 3561-3568.
Whitcomb, D. and J. Greer (2009). "Germ-line mutations, pancreatic inflammation, and pancreatic cancer." Clin Gastroenterol Hepatol 7(11 Suppl): S29-34.
Xia, N., C. K. Thodeti, T. P. Hunt, Q. Xu, M. Ho, G. M. Whitesides, R. Westervelt and D. E. Ingber (2008). "Directional control of cell motility through focal adhesion positioning and spatial control of Rac activation." Faseb j 22(6): 1649-1659.
Bourne, H. R., D. A. Sanders and F. McCormick (1990). "The GTPase superfamily: a conserved switch for diverse cell functions." Nature 348(6297): 125-132.
Colucci-D'Amato, L., C. Perrone-Capano and U. di Porzio (2003). "Chronic activation of ERK and neurodegenerative diseases." Bioessays 25(11): 1085-1095.
Hultgardh-Nilsson, A., B. Cercek, J. W. Wang, S. Naito, C. Lovdahl, B. Sharifi, J. S. Forrester and J. A. Fagin (1996). "Regulated expression of the ets-1 transcription factor in vascular smooth muscle cells in vivo and in vitro." Circ Res 78(4): 589-595.
Kim, H. (2008). "Cerulein pancreatitis: oxidative stress, inflammation, and apoptosis." Gut Liver 2(2): 74-80.
Kummerfeld, S. K. and S. A. Teichmann (2006). "DBD: a transcription factor prediction database." Nucleic Acids Res 34(Database issue): D74-81.
Manresa-Arraut, A., F. F. Johansen, C. Brakebusch, S. Issazadeh-Navikas and H. Hasseldam (2018). "RhoA Drives T-Cell Activation and Encephalitogenic Potential in an Animal Model of Multiple Sclerosis." Front Immunol 9: 1235.
Moreno-Layseca, P. and C. H. Streuli (2014). "Signalling pathways linking integrins with cell cycle progression." Matrix Biol 34: 144-153.
Norman, J. (1998). "The role of cytokines in the pathogenesis of acute pancreatitis." Am J Surg 175(1): 76-83.
van Horck, F. P., M. R. Ahmadian, L. C. Haeusler, W. H. Moolenaar and O. Kranenburg (2001). "Characterization of p190RhoGEF, a RhoA-specific guanine nucleotide exchange factor that interacts with microtubules." J Biol Chem 276(7): 4948-4956.
Apte, M. V., R. C. Pirola and J. S. Wilson (2012). "Pancreatic stellate cells: a starring role in normal and diseased pancreas." Front Physiol 3: 344.
Bischoff, F. and G. Bryson (1964). "CARCINOGENESIS THROUGH SOLID STATE SURFACES." Prog Exp Tumor Res 5: 85-133.
Chronopoulos, A., B. Robinson, M. Sarper, E. Cortes, V. Auernheimer, D. Lachowski, S. Attwood, R. García, S. Ghassemi, B. Fabry and A. del Río Hernández (2016). "ATRA mechanically reprograms pancreatic stellate cells to suppress matrix remodelling and inhibit cancer cell invasion." Nature Communications 7: 12630.
Grossman, S. P. (1986). "The role of glucose, insulin and glucagon in the regulation of food intake and body weight." Neurosci Biobehav Rev 10(3): 295-315.
Kuno, A., T. Yamada, K. Masuda, K. Ogawa, M. Sogawa, S. Nakamura, T. Nakazawa, H. Ohara, T. Nomura, T. Joh, T. Shirai and M. Itoh (2003). "Angiotensin-converting enzyme inhibitor attenuates pancreatic inflammation and fibrosis in male Wistar Bonn/Kobori rats." Gastroenterology 124(4): 1010-1019.
Landskron, G., M. De la Fuente, P. Thuwajit, C. Thuwajit and M. A. Hermoso (2014). "Chronic inflammation and cytokines in the tumor microenvironment." J Immunol Res 2014: 149185.
Larsen, S. (1993). "Diabetes mellitus secondary to chronic pancreatitis." Dan Med Bull 40(2): 153-162.
Masamune, A., K. Kikuta, N. Suzuki, M. Satoh, K. Satoh and T. Shimosegawa (2004). "A c-Jun NH2-terminal kinase inhibitor SP600125 (anthra[1,9-cd]pyrazole-6 (2H)-one) blocks activation of pancreatic stellate cells." J Pharmacol Exp Ther 310(2): 520-527.
McCarroll, J. A., S. Naim, G. Sharbeen, N. Russia, J. Lee, M. Kavallaris, D. Goldstein and P. A. Phillips (2014). "Role of pancreatic stellate cells in chemoresistance in pancreatic cancer." Front Physiol 5: 141.
Oberstein, P. E. and K. P. Olive (2013). "Pancreatic cancer: why is it so hard to treat?" Therap Adv Gastroenterol 6(4): 321-337.
Perusicova, J. (2002). "[Diabetes mellitus associated with chronic pancreatitis]." Vnitr Lek 48(9): 898-905.
Tomasek, J. J., G. Gabbiani, B. Hinz, C. Chaponnier and R. A. Brown (2002). "Myofibroblasts and mechano-regulation of connective tissue remodelling." Nat Rev Mol Cell Biol 3(5): 349-363.