在肺腺癌中，致癌驅動因子的突變已有藥物標的和預測指標能夠利用精準療法使用於病人。然而，不同於肺腺癌，生長快速的鱗狀上皮肺癌缺乏可行的藥物標的，因而成為治療的難題。SLC7A5是一種高度表達在快速生長的癌症中的基因，負責大型和中性的氨基酸的攝取。儘管如此，對於SLC7A5是否能在鱗狀上皮肺癌中作為治療標的和生物標記仍未被闡明。因此，在本研究中，我們除了指出SLC7A5在鱗狀上皮肺癌中具有高表現外，還能進一步預測病人將有較差的存活率。相關性分析指出SLC7A5的表現與SOX2有關，SOX2在快速生長的鱗狀上皮肺癌中作為影響細胞命運的基因。敲低SLC7A5的表現造成鱗狀上皮肺癌細胞的增殖能力降低、SOX2表現量降低和促進p21表達。而敲除SLC7A5後造成細胞譜系轉換、失去SOX2表現和減少進入細胞週期的S phase，更因此獲得了上皮間質轉化(epithelial to mesenchymal transition)的特性。我們發現當鱗狀上皮肺癌細胞在經過硼中子捕獲療法(BNCT)和cisplatin處理後會降低SLC7A5的表現。綜合上述，我們的研究結果發現，SLC7A5在快速生長的鱗狀上皮肺癌中所扮演的角色，且具有低表現SLC7A5的細胞可能與在硼中子捕獲療法和cisplatin治療中具有較高的耐受性有關。

Driver mutations in lung adenocarcinoma have provided druggable targets and predictive markers for targeted therapies in patients. However, unlike lung adenocarcinoma, the lack of druggable targets and approved targeted therapies in fast-growing lung squamous cell carcinoma has imposed a challenge in patient treatment. The solute carrier family 7 member 5 (SLC7A5), a transporter responsible for uptake of large and neutral amino acids, is highly expressed in fast-growing cancers. Nonetheless, the role of SLC7A5 as a therapeutic target and biomarker in lung squamous cell carcinoma has yet to be examined. In the present study, we report that SLC7A5 is highly expressed in lung squamous cell carcinoma and its high expression predicts a poor survival outcome in patients. Correlation analysis showed that SLC7A5 expression was associated with SOX2, a cell fate determining gene of fast-growing lung squamous cell carcinoma. Knockdown of SLC7A5 attenuated the ability of proliferation and decreased SOX2 expression while inducing p21 expression in lung squamous cell carcinoma cells. Knockout of SLC7A5 caused lineage switch to lose SOX2 expression and decrease S phase cell cycle entry, whereas gaining epithelial to mesenchymal transition feature in cancer cells. Treatment of lung squamous cell carcinoma cells with boron neutron capture therapy (BNCT) and cisplatin reduced SLC7A5 expression. Our findings support an essential role of SLC7A5 in fast-growing lung squamous cell carcinoma, and the decreased expression of SLC7A5 may contribute to tolerant state to BNCT and cisplatin treatments.

Abstract………………………………………………………………1
摘要…………………………………………………………………… 3
Acknowledgement……………………………………………4
Introduction………………………………………………………………6
Materials and Methods…………………………………………………13
Results…………………………………………………………………20
Discussion………………………………………………………………26
Figures…………………………………………………………………30
References………………………………………………………………44

1. 衛生福利部國民健康署, 109年死因結果分析. 2021.
2. Rodriguez-Canales, J., E. Parra-Cuentas, and Wistuba, II, Diagnosis and Molecular Classification of Lung Cancer. Cancer Treat Res, 2016. 170: p. 25-46.
3. Duma, N., R. Santana-Davila, and J.R. Molina, Non-Small Cell Lung Cancer: Epidemiology, Screening, Diagnosis, and Treatment. Mayo Clin Proc, 2019. 94(8): p. 1623-1640.
4. Lim, S.M., M.H. Hong, and H.R. Kim, Immunotherapy for Non-small Cell Lung Cancer: Current Landscape and Future Perspectives. Immune Netw, 2020. 20(1): p. e10.
5. Shtivelman E, H.T., Simon GR, Dennis PA, Otterson GA, Bueno R, Salgia R. Molecular pathways and therapeutic targets in lung cancer. Oncotarget. 2014 Mar 30;5(6):1392-433. doi: 10.18632/oncotarget.1891. , Molecular pathways and therapeutic targets in lung cancer. Oncotarget, 2014. 5(6): p. 1392-433.
6. Jackman, D., et al., Clinical definition of acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors in non-small-cell lung cancer. J Clin Oncol, 2010. 28(2): p. 357-60.
7. Barth RF, V.M., Harling OK, Kiger WS 3rd, Riley KJ, Binns PJ, Wagner FM, Suzuki M, Aihara T, Kato I, Kawabata S. , Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer. Radiat Oncol, 2012. 7: p. 146.
8. Nedunchezhian, K., et al., Boron Neutron Capture Therapy - A Literature Review. J Clin Diagn Res, 2016. 10(12): p. ZE01-ZE04.
9. Barth, R.F., P. Mi, and W. Yang, Boron delivery agents for neutron capture therapy of cancer. Cancer Commun (Lond), 2018. 38(1): p. 35.
10. Wittig A, S.W., Coderre JA. , Mechanisms of transport of p-borono-phenylalanine through the cell membrane in vitro. Radiat Res, 2000. 153(2): p. 173-80.
11. Wang, L.W., et al., Clinical trials for treating recurrent head and neck cancer with boron neutron capture therapy using the Tsing-Hua Open Pool Reactor. Cancer Commun (Lond), 2018. 38(1): p. 37.
12. Farias, R.O., et al., Exploring Boron Neutron Capture Therapy for non-small cell lung cancer. Phys Med, 2014. 30(8): p. 888-97.
13. Yu, H., et al., Influence of Neutron Sources and 10B Concentration on Boron Neutron Capture Therapy for Shallow and Deeper Non-small Cell Lung Cancer. Health Phys, 2017. 112(3): p. 258-265.
14. HN., C., Role of amino acid transport and countertransport in nutrition and metabolism. Physiol Rev., 1990. 70(1): p. 43-77.
15. Meier C, R.Z., Klauser S, Verrey F. , Activation of system L heterodimeric amino acid exchangers by intracellular substrates. EMBO J, 2002. 21(4): p. 580-9.
16. Yanagida O, K.Y., Chairoungdua A, Kim DK, Segawa H, Nii T, Cha SH, Matsuo H, Fukushima J, Fukasawa Y, Tani Y, Taketani Y, Uchino H, Kim JY, Inatomi J, Okayasu I, Miyamoto K, Takeda E, Goya T, Endou H. , Human L-type amino acid transporter 1 (LAT1) - characterization of function and expression in tumor cell lines. Biochim Biophys Acta, 2001. 1514(2): p. 291-302.
17. Kanai, Y., et al., Expression cloning and characterization of a transporter for large neutral amino acids activated by the heavy chain of 4F2 antigen (CD98). J Biol Chem, 1998. 273(37): p. 23629-32.
18. Friesema EC, D.R., Moerings EP, Verrey F, Krenning EP, Hennemann G, Visser TJ. , Thyroid hormone transport by the heterodimeric human system L amino acid transporter. Endocrinology, 2001. 142(10): p. 4339-48.
19. del Amo, E.M., A. Urtti, and M. Yliperttula, Pharmacokinetic role of L-type amino acid transporters LAT1 and LAT2. Eur J Pharm Sci, 2008. 35(3): p. 161-74.
20. Fotiadis, D., Y. Kanai, and M. Palacin, The SLC3 and SLC7 families of amino acid transporters. Mol Aspects Med, 2013. 34(2-3): p. 139-58.
21. Furuya, M., et al., Correlation of L-type amino acid transporter 1 and CD98 expression with triple negative breast cancer prognosis. Cancer Sci, 2012. 103(2): p. 382-9.
22. Namikawa, M., et al., Expression of amino acid transporters (LAT1, ASCT2 and xCT) as clinical significance in hepatocellular carcinoma. Hepatol Res, 2015. 45(9): p. 1014-1022.
23. Kaira, K., et al., Prognostic significance of L-type amino acid transporter 1 expression in resectable stage I-III nonsmall cell lung cancer. Br J Cancer, 2008. 98(4): p. 742-8.
24. Kaira, K., et al., Expression of L-type amino acid transporter 1 (LAT1) in neuroendocrine tumors of the lung. Pathol Res Pract, 2008. 204(8): p. 553-61.
25. Haining Z, K.N., Miyake K, Okada M, Okubo S, Zhang X, Fei Z, Tamiya T. , Relation of LAT1/4F2hc expression with pathological grade, proliferation and angiogenesis in human gliomas. BMC Clin Pathol, 2012. 12: p. 4.
26. Cormerais, Y., et al., Genetic Disruption of the Multifunctional CD98/LAT1 Complex Demonstrates the Key Role of Essential Amino Acid Transport in the Control of mTORC1 and Tumor Growth. Cancer Res, 2016. 76(15): p. 4481-92.
27. Shennan, Inhibition of system L (LAT1/CD98hc) reduces the growth of cultured human breast cancer cells. Oncology Reports, 1994. 20(4).
28. Oda, K., et al., L-type amino acid transporter 1 inhibitors inhibit tumor cell growth. Cancer Sci, 2010. 101(1): p. 173-9.
29. Kim CS, C.S., Chun HS, Lee SY, Endou H, Kanai Y, Kim DK., BCH, an inhibitor of system L amino acid transporters, induces apoptosis in cancer cells. Biol Pharm Bull., 2008. 31(6): p. 1096-100.
30. Singh, N., et al., Discovery of Potent Inhibitors for the Large Neutral Amino Acid Transporter 1 (LAT1) by Structure-Based Methods. Int J Mol Sci, 2018. 20(1).
31. Fong, H., K.A. Hohenstein, and P.J. Donovan, Regulation of self-renewal and pluripotency by Sox2 in human embryonic stem cells. Stem Cells, 2008. 26(8): p. 1931-8.
32. Maier, S., et al., SOX2 amplification is a common event in squamous cell carcinomas of different organ sites. Hum Pathol, 2011. 42(8): p. 1078-88.
33. Chou, Y.T., et al., The emerging role of SOX2 in cell proliferation and survival and its crosstalk with oncogenic signaling in lung cancer. Stem Cells, 2013. 31(12): p. 2607-19.
34. Lin SC, C.Y., Jiang SS, Chang JL, Chung CH, Kao YR, Chang IS, Wu CW. , Epigenetic Switch between SOX2 and SOX9 Regulates Cancer Cell Plasticity. Cancer Res, 2016. 76(23): p. 7036-7048.
35. Kuo, M.H., et al., Cross-talk between SOX2 and TGFbeta Signaling Regulates EGFR-TKI Tolerance and Lung Cancer Dissemination. Cancer Res, 2020. 80(20): p. 4426-4438.
36. Zhang, J., et al., Sex-determining region Y-box 2 expression predicts poor prognosis in human ovarian carcinoma. Hum Pathol, 2012. 43(9): p. 1405-12.
37. Piva, M., et al., Sox2 promotes tamoxifen resistance in breast cancer cells. EMBO Mol Med, 2014. 6(1): p. 66-79.
38. Dongre, A. and R.A. Weinberg, New insights into the mechanisms of epithelial-mesenchymal transition and implications for cancer. Nat Rev Mol Cell Biol, 2019. 20(2): p. 69-84.
39. Nieto, M.A., et al., EMT: 2016. Cell, 2016. 166(1): p. 21-45.
40. Zhang, Y. and R.A. Weinberg, Epithelial-to-mesenchymal transition in cancer: complexity and opportunities. Front Med, 2018. 12(4): p. 361-373.
41. Wilbertz T, W.P., Petersen K, Stiedl AC, Scheble VJ, Maier S, Reischl M, Mikut R, Altorki NK, Moch H, Fend F, Staebler A, Bass AJ, Meyerson M, Rubin MA, Soltermann A, Lengerke C, Perner S. , SOX2 gene amplification and protein overexpression are associated with better outcome in squamous cell lung cancer. Mod Pathol, 2011. 24(7): p. 944-53.
42. Huang, S.S. and J.S. Huang, TGF-beta control of cell proliferation. J Cell Biochem, 2005. 96(3): p. 447-62.
43. Hayashi, K., et al., c-Myc is crucial for the expression of LAT1 in MIA Paca-2 human pancreatic cancer cells. Oncol Rep, 2012. 28(3): p. 862-6.
44. Kochanowski, K., et al., Drug persistence - from antibiotics to cancer therapies. Curr Opin Syst Biol, 2018. 10: p. 1-8.
45. Ghosh, S., Cisplatin: The first metal based anticancer drug. Bioorg Chem, 2019. 88: p. 102925.
46. Li, J., et al., Gene expression response to cisplatin treatment in drug-sensitive and drug-resistant ovarian cancer cells. Oncogene, 2007. 26(20): p. 2860-72.
47. Meng, L., et al., Tumor suppressive miR-6775-3p inhibits ESCC progression through forming a positive feedback loop with p53 via MAGE-A family proteins. Cell Death Dis, 2018. 9(11): p. 1057.