Sorafenib down-regulates expression of HTATIP2 to promote invasiveness and metastasis of orthotopic hepatocellular carcinoma tumors in mice.

BACKGROUND & AIMS: Antiangiogenic agents can sometimes promote tumor invasiveness and metastasis, but little is known about the effects of the antiangiogenic drug sorafenib on progression of hepatocellular carcinoma (HCC).

METHODS: Sorafenib was administered orally (30 mg · kg(-1) · day(-1)) to mice with orthotopic tumors grown from HCC-LM3, SMMC7721, or HepG2 cells. We analyzed survival times of mice, along with tumor growth, metastasis within liver and to lung, and induction of the epithelial-mesenchymal transition. Polymerase chain reaction arrays were used to determine the effects of sorafenib on gene expression patterns in HCC cells. We analyzed regulation of HIV-1 Tat interactive protein 2 (HTATIP2) by sorafenib and compared levels of this protein in tumor samples from 75 patients with HCC (21 who received sorafenib after resection and 54 who did not).

RESULTS: Sorafenib promoted invasiveness and the metastatic potential of orthotopic tumors grown from SMMC7721 and HCC-LM3 cells but not from HepG2 cells. In gene expression analysis, HTATIP2 was down-regulated by sorafenib. HCC-LM3 cells that expressed small hairpin RNAs against HTATIP2 (knockdown) formed less invasive tumors in mice following administration of sorafenib than HCC-LM3 without HTATIP2 knockdown. Alternatively, HepG2 cells that expressed transgenic HTATIP2 formed more invasive tumors in mice following administration of sorafenib. Sorafenib induced the epithelial-mesenchymal transition in HCC cell lines, which was associated with expression of HTATIP2. Sorafenib regulated expression of HTATIP2 via Jun-activated kinase (JAK) and signal transducer and activator of transcription (STAT)3 signaling. Sorafenib therapy prolonged recurrence-free survival in patients who expressed lower levels of HTATIP2 compared with higher levels.

CONCLUSIONS: Sorafenib promotes invasiveness and the metastatic potential of orthotopic tumors from HCC cells in mice, down-regulating expression of HTATIP2 via JAK-STAT3 signaling.