Liver cancer comprises a group of malignant tumors, among which hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common. ICC is especially pernicious and associated with poor clinical outcome. Studies have shown that a subset of human ICCs may originate from mature hepatocytes. However, the mechanisms driving the trans-differentiation of hepatocytes into malignant cholangiocytes remain poorly defined. We adopted lineage tracing techniques and an established murine hepatocyte-derived ICC model by hydrodynamic injection of activated forms of AKT (myr-AKT) and Yap (YapS127A) proto-oncogenes. Wild-type, Notch1 ^flox/flox , and Notch2 ^flox/flox mice were used to investigate the role of canonical Notch signaling and Notch receptors in AKT/Yap-driven ICC formation. Human ICC and HCC cell lines were transfected with siRNA against Notch2 to determine whether Notch2 regulates biliary marker expression in liver tumor cells. We found that AKT/Yap-induced ICC formation is hepatocyte derived and this process is strictly dependent on the canonical Notch signaling pathway in vivo. Deletion of Notch2 in AKT/Yap-induced tumors switched the phenotype from ICC to hepatocellular adenoma-like lesions, while inactivation of Notch1 in hepatocytes did not result in significant histomorphological changes. Finally, in vitro studies revealed that Notch2 silencing in ICC and HCC cell lines down-regulates the expression of Sox9 and EpCAM biliary markers. Notch2 is the major determinant of hepatocyte-derived ICC formation in mice.

Background/aim

Xihuang Wan (XHW), a traditional Chinese medicine (TCM), has been used in China for a variety of cancers including lung cancer. The present study evaluated the efficacy of XHW on a Lewis lung mouse model and explored the potential mechanism via transcriptomics.

Materials and methods

The mice were randomized into 6 groups: 1) untreated control (n=10); 2) low-dose XHW; 3) medium-dose XHW; 4) high-dose XHW; 5) cisplatin; and 6) untreated blank (n=4). Lewis lung carcinoma (LLC) cells were injected subcutaneously except for the 4 mice in the blank group. The body weight and tumor length and width were measured every 3 days. RNA-sequencing was performed on tumors in the high-dose XHW group and the control group.

Results

XHW inhibited the growth of LLC in a syngeneic mouse model, without toxicity, with equivalent efficacy to cisplatin. RNA-sequencing demonstrated that many signaling pathways were involved in XHW-mediated inhibition of LLC, including tumor necrosis factor, estrogen, cyclic guanosine 3', 5'-monophosphate-protein kinase G, apelin and the peroxisome proliferator-activated receptor signaling pathways.

Conclusion

XHW inhibited LLC carcinoma through different pathways and shows clinical promise for patients who cannot tolerate platinum-based drugs.

Liver metastasis is a recalcitrant disease that usually leads to death of the patient. The present study established a unique patient-derived orthotopic xenograft (PDOX) nude mouse model of a highly aggressive liver metastasis of colon cancer. The aim of the present study was to demonstrate proof-of-concept that candidate drug combinations could significantly inhibit growth and re-metastasis of this recalcitrant tumor. The patient's liver metastasis was initially established subcutaneously in nude mice and the subcutaneous tumor tissue was then orthotopically implanted in the liver of nude mice to establish a PDOX model. Two studies were performed to test different drugs or drug combination, indicating that 5-fluorouracil (5-FU) + irinotecan (IRI) + bevacizumab (BEV) and regorafenib (REG) + selumetinib (SEL) had significantly inhibited liver metastasis growth (p = 0.013 and p = 0.035, respectively), and prevented liver satellite metastasis. This study is proof of concept that a PDOX model of highly aggressive colon-cancer metastasis can identify effective drug combinations and that the model has future clinical potential.