Prothymosin α/HOTAIR透過EGFR使膀胱癌病人接受化療後產生惡病質

胡哲源¹，謝嘉興 ²

¹成大醫院，²衛生福利部台南醫院

Prothymosin α/HOTAIR signaling axis regulates cachexia in bladder cancer patients during cisplatin chemotherapy in an EGFR-dependent manner

Che-Yuan Hu¹, Gia-Shing Shieh ²

¹Department of Urology, National Cheng Kung University Hospital

²Department of Urology, Tainan Hospital, Department of Health, Executive Yuan, Tainan, Taiwan

Purpose:

Cachexia is one of the leading causes of cancer-related deaths in advanced or metastatic cancer. Cisplatin-based chemotherapy remains the first line of choice in treating metastatic bladder cancer (BCa), however, chemotherapy itself can induce muscle wasting and body weight loss. It negatively affects patients’ quality of life and brings poor prognosis. Little is known about the underlying mechanisms why chemotherapeutic agents also lead to the development and progression of cachexia. We investigated the role of Prothymosin α (ProT) and lncRNA HOTAIR during the formation of cachexia, and the possible correlation with the EGFR expression induced by chemotherapy.

Materials and Methods:

We evaluated the correlation of ProT and HOTAIR from specimens of BCa patients who received transurethral resection of bladder tumor (TURBT). Next we checked the expression of ProT and HOTAIR in various human cancer cell lines, and whether knockdown or overexpression of ProT will affect HOTAIR level in these cells. We used cisplatin to treat bladder cancer cells and evaluated the change on expression of EGFR, ProT and HOTAIR. EGFR inhibitor was also utilized to confirm the upstream role of EGFR in signaling pathway. We also knocked down HOTAIR expression by CRISPRi in murine MBT-2 bladder cancer cells and measured the alteration of cytokine level. MBT-2 syngeneic bladder tumor model in C3H/HeN mice was treated with cisplatin to induce cachexia. We examined the status of muscle atrophy and cachexia factors with or without inhibition of HOTAIR expression.

Results:

Elevated ProT and HOTAIR were noted in BCa patients’ tumor compared with adjacent normal tissue. Besides, the expression between ProT and HOTAIR was highly correlated (r²= 0.799, p< 0.0001). The condition was also noted in bladder cancer cell lines. In vitro data suggested that treatment with cisplatin in BCa cells enhanced the expression of EGFR, ProT and HOTAIR. Giving EGFR antagonist reversed the overexpression of ProT and HOTAIR. ProT upregulated HOTAIR expression, and the mechanism was dependent on NF-κB activation. Moreover, knockdown of HOTAIR in MBT-2 murine bladder cancer cells decreased the downstream cytokines related to cachexia, and in vivo study showed that cisplatin-induced cachexia was ameliorated in HOTAIR-silenced mice by observation of increased calf circumference, cross-sectional area of myofiber, and downregulation of cachexia factors.

Conclusions:

Chemotherapy-induced cachexia may be related to HOTAIR upregulation, and EGFR-ProT-HOTAIR axis may play vital role in the development of cachexia. Reversion of this signal transduction pathway may be a potential therapeutic target in clinical practice.