Arsenic trioxide inhibits cholangiocarcinoma cell growth and induces apoptosis

The ATO/miRNA-885-5p/MTPN axis induces reversal of drug-resistance in cholangiocarcinoma

PURPOSE

Cholangiocarcinoma (CCA) is the second most malignant tumor of the hepatobiliary system. Due to its cumbersome early diagnosis and rapid progression, chemotherapy has become the main treatment option. Primary drug resistance is a major cause of the poor efficacy of chemotherapeutic drugs. Therefore, it is considered urgent to explore new drugs to overcome primary drug resistance of CCA.

METHODS

Western blot and qRT-PCR assays were used to assess the expression of myotrophin (MTPN) and microRNA-885-5p (miR-885-5p) in CCA tissues and cells. The viability of CCA cells treated with arsenic trioxide (ATO), 5-fluorouracil (5-Fu) and cisplatin (CDDP) was analyzed using a CCK-8 assay. A luciferase reporter assay was used to assess the interaction between miR-885-5p and MTPN. Kaplan-Meier analyses were used for survival assessments.

RESULT

We found that ATO can reduce the resistance of CCA cells to 5-Fu and CDDP and promote the killing effect of 5-Fu and CDDP. Low-dose ATO showed an anti-drug-resistance effect through up-regulation of the expression of miR-885-5p. Combined with sequencing results and database predictions, we found that MTPN may serve as a direct target of miR-885-5p. After MTPN knockdown, the sensitivity of CCA cells to 5-FU and CDDP was increased. Finally, we found that ATO can reverse chemotherapy resistance induced by overexpression of MTPN.

CONCLUSION

Our data indicate that the ATO/miR-885-5p/MTPN axis may serve as a target for improving the sensitivity of CCA cells to chemotherapy.

Autophagy as a Potential Therapy for Malignant Glioma

Glioma is the most frequent and aggressive type of brain neoplasm, being anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM), its most malignant forms. The survival rate in patients with these neoplasms is 15 months after diagnosis, despite a diversity of treatments, including surgery, radiation, chemotherapy, and immunotherapy. The resistance of GBM to various therapies is due to a highly mutated genome; these genetic changes induce a de-regulation of several signaling pathways and result in higher cell proliferation rates, angiogenesis, invasion, and a marked resistance to apoptosis; this latter trait is a hallmark of highly invasive tumor cells, such as glioma cells. Due to a defective apoptosis in gliomas, induced autophagic death can be an alternative to remove tumor cells. Paradoxically, however, autophagy in cancer can promote either a cell death or survival. Modulating the autophagic pathway as a death mechanism for cancer cells has prompted the use of both inhibitors and autophagy inducers. The autophagic process, either as a cancer suppressing or inducing mechanism in high-grade gliomas is discussed in this review, along with therapeutic approaches to inhibit or induce autophagy in pre-clinical and clinical studies, aiming to increase the efficiency of conventional treatments to remove glioma neoplastic cells.

Arsenic sulfide as a potential anti‑cancer drug

Arsenic sulfide (As4S4) is the main component of realgar, which is widely used in traditional Chinese medicine. Previous studies have shown the beneficial effects of As4S4 in the treatment of hematological malignant diseases, however, its effects on solid tumors have yet to be fully elucidated. The current study aimed to explore the anti‑cancer effect and the mechanism of As4S4 on solid tumors in vitro and in vivo. Cells from four human solid tumor cell lines, including the MKN45 gastric cancer cell line, the A375 malignant melanoma cell line, the 8898 pancreatic carcinoma cell line and the HepG2 hepatocellular carcinoma cell line, were treated with As4S4 in vitro, using the L02 embryonic liver cells as a control. The efficacy of As4S4 was assessed in vivo using mice implanted with Lewis lung carcinoma cells. The results of the current study demonstrated that As4S4 significantly inhibited the proliferation of solid tumor cells in a dose‑ and time‑dependent manner, but produced a less pronounced effect on L02 cells. Additionally, As4S4 was observed to induce apoptosis (including morphological changes and an enhanced sub‑G1 population), which was accompanied by the activation of caspase‑3 and ‑9. Furthermore, treatment with As4S4 significantly inhibited the growth of implanted tumors in mice. These results suggest that As4S4 possesses potent in vitro and in vivo antitumor activity via the induction of cell apoptosis.

Anticancer effect of arsenic trioxide on cholangiocarcinoma: in vitro experiments and in vivo xenograft mouse model

The purpose of our study was to investigate anticancer activity of arsenic trioxide (As2O3) on cholangiocarcinoma through in vitro and in vivo experiments using human cholangiocarcinoma cancer cells (CC-t6 cells) and a nude mouse model. The effect of As2O3 on CC-t6 cell survival was determined in vitro using MTT assay. Analysis of cell cycle phase distribution and quantification of apoptosis/necrosis, which were achieved by flow cytometry, were performed in order to understand the mechanism of As2O3. In vivo experiment was performed to assess the effectiveness of local injection of As2O3 on tumor inhibition by comparing the following three groups each consisting of five nude mouse xenograft models: high dose As2O3 (5 mg/kg), low dose As2O3 (1 mg/kg), and saline. In MTT assay, As2O3 inhibited the growth of CC-t6 cells more effectively than cisplatin or adriamycin at concentrations between 1 and 100 μM for most time points between 24 and 72 h (p < 0.05). With increased concentration of As2O3, there was dose-dependent increase in G 0/G 1 phase and dose-dependent decrease in S phase. As2O3-mediated inhibition of cell viability was achieved via induction of apoptosis and necrosis in a dose-dependent manner. Injection of As2O3 into CC-t6-induced tumors in nude mice inhibited the growth of subcutaneous tumor xenografts. As2O3 treatment dose-dependently inhibited the proliferation of CC-t6 cells via G 0/G 1 phase arrest and retarded tumor growth in nude mice, suggesting that As2O3 may be effective in the treatment of cholangiocarcinoma.

Role of the stromal-derived factor-1 (SDF-1)-CXCR4 axis in the interaction between hepatic stellate cells and cholangiocarcinoma

BACKGROUNDS & AIMS

Cholangiocarcinoma (CCA) is highly fatal because of early invasion, widespread metastasis, and lack of an effective therapy. Migration, invasion, and metastasis of CCA cells are modulated by signals received from stromal cells. The SDF-1-CXCR4 axis emerges as a pivotal regulator of migration and survival of different tumor cells. The aim of the present study was to characterize the interaction between CCA cells and human hepatic stellate cells (hHSC) focusing on the role of SDF-1.

METHODS

The intrahepatic CCA cell line HuCCT-1 and primary hHSC were used for this study. RNA expression was examined by RTQ-PCR and protein expression by Western blotting. Immunofluorescence microscopy and immunohistochemistry were also employed. Migration of CCA cells was assessed using modified Boyden chambers.

RESULTS

CXCR4 was clearly expressed in CCA cells of human CCA liver specimens. SDF-1 and hHSC conditioned medium (CM) promoted HuCCT-1 cell migration, which was abrogated by pre-incubation with AMD3100, a non-peptide antagonist of the CXCR4 receptor. In addition, HuCCT-1 cells silenced for CXCR4 did not migrate in presence of SDF-1. Both P-ERK and p-AKT were implicated in HuCCT-1 migration and showed a biphasic trend under stimulation of SDF-1. Finally, SDF-1 induced apoptotic rescue of HuCCT-1 cells by binding to CXCR4.

CONCLUSIONS

Our study demonstrates that CCA cells migration and survival are modulated by the crosstalk between SDF-1, released by hHSC, and HuCCT-1 cells bearing CXCR4.

Interleukin-6-driven progranulin expression increases cholangiocarcinoma growth by an Akt-dependent mechanism

BACKGROUND AND OBJECTIVES

Cholangiocarcinoma is a devastating cancer of biliary origin with limited treatment options. The growth factor, progranulin, is overexpressed in a number of tumours. The study aims were to assess the expression of progranulin in cholangiocarcinoma and to determine its effects on tumour growth.

METHODS

The expression and secretion of progranulin were evaluated in multiple cholangiocarcinoma cell lines and in clinical samples from patients with cholangiocarcinoma. The role of interleukin 6 (IL-6)-mediated signalling in the expression of progranulin was assessed using a combination of specific inhibitors and shRNA knockdown techniques. The effect of progranulin on proliferation and Akt activation and subsequent effects of FOXO1 phosphorylation were assessed in vitro. Progranulin knockdown cell lines were established, and the effects on cholangiocarcinoma growth were determined.

RESULTS

Progranulin expression and secretion were upregulated in cholangiocarcinoma cell lines and tissue, which were in part via IL-6-mediated activation of the ERK1/2/RSK1/C/EBPβ pathway. Blocking any of these signalling molecules, by either pharmacological inhibitors or shRNA, prevented the IL-6-dependent activation of progranulin expression. Treatment of cholangiocarcinoma cells with recombinant progranulin increased cell proliferation in vitro by a mechanism involving Akt phosphorylation leading to phosphorylation and nuclear extrusion of FOXO1. Knockdown of progranulin expression in cholangiocarcinoma cells decreased the expression of proliferating cellular nuclear antigen, a marker of proliferative capacity, and slowed tumour growth in vivo.

CONCLUSIONS

Evidence is presented for a role for progranulin as a novel growth factor regulating cholangiocarcinoma growth. Specific targeting of progranulin may represent an alternative for the development of therapeutic strategies.