胰島管腺癌是所有癌症中最惡性的腫瘤之一,伴隨著高致死率,五年存活率不到百分之五。由於大部分胰腺癌患者缺乏早期症狀,多在腫瘤擴散後才被確診為後期。 胰腺癌的轉移有許多複雜的機制參與,包含上皮細胞變間質細胞的轉換、血管新生、 淋巴管新生及淋巴轉移。先前文獻指出免疫細胞會滲入腫瘤微環境當中,並且促進腫 瘤細胞的發展。因此,我們提出假說,在胰腺癌腫瘤微環境的腫瘤相關纖維母細胞(胰 腺星狀細胞)、免疫細胞(單核細胞和巨噬細胞)可能會造成腫瘤的轉移。我們利用 人類胰腺星狀細胞、單核細胞和 PMA 分化成巨噬細胞收集而來的條件培養液培養胰 腺癌細胞,結果發現巨噬細胞條件培養基會造成胰腺癌細胞形態改變,以及增加細胞 的移動能力和爬行能力。更進一步,我們發現在巨噬細胞處理過後的胰腺癌細胞,細 胞外調控蛋白激酶的活性增加以及 E-鈣黏蛋白的表現量下降。此外,巨噬細胞條件 培養基當中的胞外體會增加細胞外調控蛋白激酶的活性。經由巨噬細胞條件培養基篩 選後的胰腺癌細胞原位注射於老鼠胰臟,結果顯示活化細胞外調控蛋白激酶與腫瘤的 生長、淋巴血管新生以及肝臟轉移相關。使用新穎新穎的組織蛋白去乙醯酶抑制劑之 抗癌藥物抗癌藥物可以壓制壓制巨噬細胞所造成的上皮變間質細胞的轉換和淋巴血 管新生。綜合以上,我們闡明在胰腺癌細胞進程中,巨噬細胞是透過活化細胞外調控蛋白激酶以及其下游路近路徑路徑,促使腫瘤轉移。最後,我們希望可以利用抑制細 胞外調控蛋白激酶的活性做為治療方針以減少胰腺癌的惡性發展。

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant cancers with high mortality rate that 5-year survival is less of 5%. Due to the lack of early symptoms, most PDAC patients were diagnosed at later-stage after the tumor has disseminated. The metastasis of PDAC is a complex mechanism which involves EMT process, angiogenesis, lymphangiogenesis and lymphatic metastasis. Previous studies have shown that immune cells infiltrate into the tumor microenvironment to promote cancer development. Thus, we hypothesize that tumor associated fibroblasts (pancreatic stellate cells) and immune cells (monocytes and macrophages) in tumor microenvironment may cause tumor metastasis in PDAC. We cultured PANC-1 cells with conditioned medium (CM) collected from human pancreatic stellate cells (HPasteC), naïve monocyte, or PMA-differentiated macrophages. Our results show that macrophage-derived CM (MCM) induced cell morphology change, increased cell movement and migration ability. We further detected ERK activation and E-cadherin suppression in MCM-treated PANC-1 cells. Exosomes in MCM are involved in MCM-induced ERK activation in PDAC cells. We further performed orthotopic injection of MCM-selected PANC-1 cells into the mouse pancreas and showed that ERK activation correlates with tumor growth, lymphangiogenesis and liver metastasis. Furthermore, we used novel HDAC inhibitor to ameliorate cancer EMT and lymphangiogenesis. Together, we demonstrate that macrophages promote PDAC progression via activation of ERK and its downstream targets. Ultimately, we hope to identify ways to prevent ERK over-activation and inhibit tumor malignancy in PDAC.

1. Siegel, R., Ward, E., Brawley, O. & Jemal, A. Cancer statistics, 2011: the impact of eliminating socioeconomic and racial disparities on premature cancer deaths. CA Cancer J. Clin. 61, 212-236 (2011).
2. Fokas, E. et al. Pancreatic ductal adenocarcinoma: From genetics to biology to radiobiology to oncoimmunology and all the way back to the clinic. Biochim. Biophys. Acta 1855, 61-82 (2015).
3. Matthaei, H., Schulick, R.D., Hruban, R.H. & Maitra, A. Cystic precursors to invasive pancreatic cancer. Nat. Rev. Gastroenterol. Hepatol. 8, 141-150 (2011).
4. Hruban, R.H. et al. Pancreatic intraepithelial neoplasia: a new nomenclature and classification system for pancreatic duct lesions. Am. J. Surg. Pathol. 25, 579-586 (2001).
5. Hezel, A.F., Kimmelman, A.C., Stanger, B.Z., Bardeesy, N. & Depinho, R.A. Genetics and biology of pancreatic ductal adenocarcinoma. Genes Dev. 20, 1218-1249 (2006).
6. Moskaluk, C.A., Hruban, R.H. & Kern, S.E. p16 and K-ras gene mutations in the intraductal precursors of human pancreatic adenocarcinoma. Cancer Res. 57, 2140-2143 (1997).
7. Ibrahim, I. et al. Risk of multiple pancreatic cancers in CDKN2A-p16-Leiden mutation carriers. Eur. J. Hum. Genet. (2018).
8. Redston, M.S. et al. p53 mutations in pancreatic carcinoma and evidence of common involvement of homocopolymer tracts in DNA microdeletions. Cancer Res. 54, 3025-3033 (1994).
9. Iacobuzio-Donahue, C.A. et al. DPC4 gene status of the primary carcinoma correlates with patterns of failure in patients with pancreatic cancer. J. Clin. Oncol. 27, 1806-1813 (2009).
10. Guerra, C. & Barbacid, M. Genetically engineered mouse models of pancreatic adenocarcinoma. Mol. Oncol. 7, 232-247 (2013).
11. Shiao, S.L., Ganesan, A.P., Rugo, H.S. & Coussens, L.M. Immune microenvironments in solid tumors: new targets for therapy. Genes & development 25, 2559-2572 (2011).
12. Quail, D.F. & Joyce, J.A. Microenvironmental regulation of tumor progression and metastasis. Nat. Med. 19, 1423-1437 (2013).
13. Martin, M., Wei, H. & Lu, T. Targeting microenvironment in cancer therapeutics. Oncotarget 7, 52575-52583 (2016).
14. Balkwill, F., Charles, K.A. & Mantovani, A. Smoldering and polarized inflammation in the initiation and promotion of malignant disease. Cancer Cell 7, 211-217 (2005).
15. Grivennikov, S.I., Greten, F.R. & Karin, M. Immunity, inflammation, and cancer. Cell 140, 883-899 (2010).
16. Martinez, F.O., Helming, L. & Gordon, S. Alternative activation of macrophages: an immunologic functional perspective. Annu. Rev. Immunol. 27, 451-483 (2009).
17. Matsuo, Y. et al. CXCL8/IL-8 and CXCL12/SDF-1alpha co-operatively promote invasiveness and angiogenesis in pancreatic cancer. Int. J. Cancer 124, 853-861 (2009).
18. Pylayeva-Gupta, Y., Grabocka, E. & Bar-Sagi, D. RAS oncogenes: weaving a tumorigenic web. Nat. Rev. Cancer 11, 761-774 (2011).
19. Eser, S., Schnieke, A., Schneider, G. & Saur, D. Oncogenic KRAS signalling in pancreatic cancer. Br. J. Cancer 111, 817-822 (2014).
20. Collisson, E.A. et al. A central role for RAF-->MEK-->ERK signaling in the genesis of pancreatic ductal adenocarcinoma. Cancer Discov. 2, 685-693 (2012).
21. Eser, S. et al. Selective requirement of PI3K/PDK1 signaling for Kras oncogene-driven pancreatic cell plasticity and cancer. Cancer Cell 23, 406-420 (2013).
22. Hugo, H. et al. Epithelial--mesenchymal and mesenchymal--epithelial transitions in carcinoma progression. J. Cell. Physiol. 213, 374-383 (2007).
23. Valastyan, S. & Weinberg, R.A. Tumor metastasis: molecular insights and evolving paradigms. Cell 147, 275-292 (2011).
24. Thiery, J.P. Epithelial-mesenchymal transitions in tumour progression. Nat. Rev. Cancer 2, 442-454 (2002).
25. Jechlinger, M., Grunert, S. & Beug, H. Mechanisms in epithelial plasticity and metastasis: insights from 3D cultures and expression profiling. J. Mammary Gland Biol. Neoplasia 7, 415-432 (2002).
26. Shi, Y. & Massague, J. Mechanisms of TGF-beta signaling from cell membrane to the nucleus. Cell 113, 685-700 (2003).
27. Hotz, B. et al. Epithelial to mesenchymal transition: expression of the regulators snail, slug, and twist in pancreatic cancer. Clin. Cancer Res. 13, 4769-4776 (2007).
28. Arumugam, T. et al. Epithelial to mesenchymal transition contributes to drug resistance in pancreatic cancer. Cancer Res. 69, 5820-5828 (2009).
29. Rasheed, Z.A. et al. Prognostic significance of tumorigenic cells with mesenchymal features in pancreatic adenocarcinoma. J. Natl. Cancer Inst. 102, 340-351 (2010).
30. Jung, H.Y., Fattet, L. & Yang, J. Molecular pathways: linking tumor microenvironment to epithelial-mesenchymal transition in metastasis. Clin. Cancer Res. 21, 962-968 (2015).
31. Oft, M., Heider, K.H. & Beug, H. TGFbeta signaling is necessary for carcinoma cell invasiveness and metastasis. Curr. Biol. 8, 1243-1252 (1998).
32. Achen, M.G. & Stacker, S.A. Molecular control of lymphatic metastasis. Ann. N. Y. Acad. Sci. 1131, 225-234 (2008).
33. Tang, R.F. et al. Overexpression of lymphangiogenic growth factor VEGF-C in human pancreatic cancer. Pancreas 22, 285-292 (2001).
34. Kurahara, H. et al. Impact of vascular endothelial growth factor-C and -D expression in human pancreatic cancer: its relationship to lymph node metastasis. Clin. Cancer Res. 10, 8413-8420 (2004).
35. Weinel, R.J., Neumann, K., Kisker, O. & Rosendahl, A. Expression and potential role of E-cadherin in pancreatic carcinoma. Int. J. Pancreatol. 19, 25-30 (1996).
36. Pignatelli, M. et al. Loss of membranous E-cadherin expression in pancreatic cancer: correlation with lymph node metastasis, high grade, and advanced stage. J. Pathol. 174, 243-248 (1994).
37. von Burstin, J. et al. E-cadherin regulates metastasis of pancreatic cancer in vivo and is suppressed by a SNAIL/HDAC1/HDAC2 repressor complex. Gastroenterology 137, 361-371, 371.e361-365 (2009).
38. Camps, M., Nichols, A. & Arkinstall, S. Dual specificity phosphatases: a gene family for control of MAP kinase function. FASEB J. 14, 6-16 (2000).
39. Lin, S.C. et al. Suppression of dual-specificity phosphatase-2 by hypoxia increases chemoresistance and malignancy in human cancer cells. J. Clin. Invest. 121, 1905-1916 (2011).
40. Yachida, S. & Iacobuzio-Donahue, C.A. The pathology and genetics of metastatic pancreatic cancer. Arch. Pathol. Lab. Med. 133, 413-422 (2009).
41. Padera, T.P. et al. Lymphatic metastasis in the absence of functional intratumor lymphatics. Science 296, 1883-1886 (2002).
42. Zhang, P. et al. Immunoglobulin-like transcript 4 promotes tumor progression and metastasis and up-regulates VEGF-C expression via ERK signaling pathway in non-small cell lung cancer. Oncotarget 6, 13550-13563 (2015).