Chemoresistance is a leading cause of morbidity and mortality in patients with pancreatic cancer and remains an obstacle to successful treatment. The antioxidant transcription factor nuclear factor (erythroid-derived 2)-related factor 2 (NRF2), which plays important roles in tumor angiogenesis and invasiveness, is upregulated in pancreatic ductal adenocarcinoma (PDAC), where it correlates with poor survival. Here, we investigated the role of NRF2 in two 5-Fluourouracil-resistant (5-FUR) PDAC cell lines: BxPC-3 and CFPAC-1. Levels of NRF2 and antioxidants, such as heme oxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and superoxide dismutase 2 (SOD2), were higher in the chemoresistant cells than in their chemosensitive counterparts. Expression of epithelial mesenchymal transition (EMT) markers, stemness markers, including Nanog, Oct4, and CD133, and that of the drug transporter ATP binding cassette, subfamily G, member A2 (ABCG2) was also upregulated in 5-FUR PDAC cells. NRF2 knockdown reversed 5-FU resistance of PDAC cells via suppression of ABCG2 and HO-1. In summary, these data indicate that NRF2 is a potential target for resensitizing 5-FUR PDAC cells to 5-FU to improve treatment outcomes in patients with pancreatic cancer.

There is increasing need for third-line therapy of Helicobacter pylori due to increasing level of antibiotics resistance. The aim of this study was to compare rifabutin and levofloxacin rescue regimens in patients with first- and second-line Helicobacter pylori eradication failures. Patients, in whom a first treatment with proton pump inhibitor-clarithromycin-amoxicillin and a second trial with proton pump inhibitor-bismuth-tetracycline-metronidazole had failed, received treatment with either rifabutin or levofloxacin, plus amoxicillin (1 g twice daily) and standard dose proton pump inhibitor. Eradication rates were confirmed with 13C-urea breath test or rapid urease test 4 weeks after the cessation of therapy. Eradication rates were 71.4% in the rifabutin group, and 57.1% in the levofloxacin group, respectively. Although there was no significant difference in Helicobacter pylori eradication rates between two groups (p=0.656), rifabutin based regimen showed relatively higher eradication rate. Helicobacter pylori eradication rates of rifabutin- or levofloxacin-based triple therapy could not achieve enough eradication rate. Further studies would be needed on combination of levofloxacin and rifabutin-based regimen or culture based treatment.

Reactive oxygen species (ROS) play a key role in cancer development and progression. Ursodeoxycholic acid (UDCA) may possess antioxidant, anti-inflammatory and chemoprophylatic effects. Therefore, we aimed to investigate the effects and mechanisms of UDCA treatment on pancreatic cancer cells. The pancreatic cancer cell lines HPAC and Capan-1 were treated with 0.2 mM UDCA. To examine alterations in the levels of intracellular ROS, the DCF-DA stain was used and both stemness and epithelial-mesenchymal transition (EMT)-related genes were quantified using qRT-PCR and western blot analysis. The pancreatic cancer sphere culture was performed following seven days of treatment with 0.2 mM UDCA, as an indicator of stemness. Following treatment with UDCA, the level of intracellular ROS was decreased in the pancreatic cancer cells. UDCA decreased both the phosphorylation of STAT3 and the expression of peroxiredoxin II (Prx2). Furthermore, the treatment resulted in the upregulation of E-cadherin and in the downregulation of N-cadherin. In addition, UDCA decreased the expression of sex determining region Y-box 2 (Sox2) and it diminished the number of pancreatic cancer spheres formed. In conclusion UDCA suppressed the levels of intracellular ROS and Prx2 and it decreased EMT and stem cell formation in pancreatic cancer cells. Therefore, UDCA may provide favorable therapeutic benefits, through its antioxidant effects, for patients with pancreatic cancer.

Jun-Won Chung, Seok Hoo Jeong, Sun Mi Lee, Jhang Ho Pak, Gin Hyug Lee, Jin-Yong Jeong, and Jin-Ho Kim. Gut and Liver 2017;11:392-400. https://doi.org/10.5009/gnl16265

Chung CS, et al. J Korean Med Sci. 2017 Mar;32(3):421-426. https://doi.org/10.3346/jkms.2017.32.3.421

Kim JH, et al. J Korean Med Sci. 2016 Jun;31(6):873-878. https://doi.org/10.3346/jkms.2016.31.6.873