Overexpression of Src Is Associated with Worse Prognosis and Harbored the Potential as a Therapeutic Target in Urothelial Carcinoma

尿路上皮癌的Src過表達與預後較差有關，且是一個潛在的治療標的

葉碧雯1,2,7、李威明1,2,3、李經家1,2、趙子翔1,2、韋又菁4

、李學德5*、孔美蘭6*、吳文正1,2,7,8*

高雄醫學大學 泌尿學科1，高雄醫學大學附設醫院 泌尿科2，衛福部屏東醫院 泌尿科3，高雄市立大同醫院 病理科4，國立陽明醫學大學 解剖與細胞生物學研究所5，高雄榮民總醫院 醫學教育與研究科6，高雄醫學大學 再生醫學與細胞治療中心7，國立中山大學 醫學科學技術研究所8

Bi-Wen Yeh1,2,7, Wei-Ming Li1,2,3, Ching-Chia Li1,2, Zi-Shian Chao1,2, Yu-Ching Wei4, Hsueh-Te Lee5*, Mei-Lang Kung6* and Wen-Jeng Wu1,2,7,8*

Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University (KMU), Kaohsiung1; Department of Urology, KMU Hospital, Kaohsiung2; Department of Urology, Ministry of Health and Welfare Pingtung Hospital, Pingtung3; Department of Pathology, Kaohsiung Municipal Ta-Tung Hospital, KMU, Kaohsiung4; Institute of Anatomy and Cell Biology, National Yang-Ming University, Taipei5; Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung6; Regenerative Medicine and Cell Therapy Research Center, KMU, Kaohsiung7; Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan8

Purposes:

The proto-oncogene c-Src (Src) is a nonreceptor tyrosine kinase. Previous studies had revealed that its overexpression was correlated with advanced malignancy status and poor clinical prognosis in a variety of human cancers. Src interacts with multiple RTKs and further triggers multiple cellular signaling pathways, such as IL6/STAT3, PI3K/Akt, NF-kB-, and PTP4A3-downstream effectors; to promote proliferation, survival, adhesion, migration/invasion and metastatic spread. However, the role of Src involved in the progression and metastasis processes in urothelial cancer (UC) has not yet been concluded.

Materials and Methods:

One hundred and twelve UTUC specimens were analyzed for Src expression by immunohistochemistry. In addition, Src expression in UC cell lines was analyzed by RT-PCR and western blotting. In vitro characterizations of the cellular function of recombinant Src in epithelial-mesenchymal transition (EMT) and tumorigenic behaviors were performed by trans-well assay and colony formation assay, respectively. The cross-talk between Src and various markers; such as HDGF, IL6, EMT markers, cancer stemness and drug resistance related proteins expression, in UC cells were studied by Western blot and qPCR to identify the mechanisms underlying its action.

Results:

Our results shown that overexpression of Src can led to ECM degradation and increase the migration/invasion capability in UC cells. These results were derived from HDGF/Src/IL6 axis activation and further induced their downstream effectors. Besides, overexpression of cSrc can increase side population characters in UC cell lines. By treating these UC cell lines with Src tyrosine kinase inhibitors, the side population characters were diminished. In addition, Src tyrosine kinase inhibitor can decrease STAT3, EMT markers and cancer stemness CD133 marker expression. In vivo transient overexpression of Src increased tumor formation as well as the tumor size/weight in both C57BL/6 mice and NOD SCID mice. We further established Src stable clone cell line to confirm for these observations in orthotopic bladder cancer model. The results shown that overexpression of Src did result in increasing tumor formation and tumor growth (size and weight) ability. By histo-pathologic analysis, we found that increases of Src expression in UTUC tumor tissues is significantly correlated with poorer prognosis (CSS p<0.001; PFS p=0.001).

Conclusions: Our results demonstrated that block the activation of Src by inhibitor or its related pathways might have therapeutic effects for patients with Src overexpressed UC. Based on our study results, it seems that Src might be with potential to act as a potential prognostic prediction biomarker, or as a therapeutic target for those UC patients with Src overexpression. Further identification of the molecular mechanisms involved and searching for specific targetable regimens that are related to Src overexpressed UC is warranted.