[Show abstract][Hide abstract] ABSTRACT: Background and Aims: MicroRNA-21 (miR-21) is reported to be overexpressed and to contribute to proliferation, apoptosis and gemcitabine resistance in pancreatic ductal adenocarcinomas (PDACs). The aims of this study were to explore regulation of miR-21 expression by epigenetic change and its impact on chemoresistance and malignant properties of of pancreatic cancer. Materials and methods: We retrospectively collected 41 cases of advanced pancreatic cancer patients who were sensitive or resistant to gemcitabine and assessed levels of serum circulating miR-21 for correlation with cytotoxic activity. Histone acetylation in the miR-21 promoter was also studied in gemcitabine-sensitive and gemcitabine-resistant PDAC cells. Gemcitabine-resistant HPAC and PANC-1 cells were transfected with pre-miR-21 precursors (pre-miR-21) and antisense oligonucleotides (anti-miR-21), and were treated with TSA. Finally, invasion and metastasis assays were performed and alteration in mir-21, PTEN, AKT and pAKT level was evaluated in these cells. Results: Serum miR-21 levels were increased in gemcitabine- resistant PDAC patients compared with gemcitabine-sensitive subjects. The miR-21 levels were increased in 6 PDAC cells treated with gemcitabine significantly, associated with 50% inhibitory concentrations (IC50s). Histone acetylation levels at miR-21 promoter were increased in PDAC cells after treatment with gemcitabine. Enhanced invasion and metastasis, increased miR-21 expression, decreased PTEN, elevated pAKT level were demonstrated in gemcitabine-resistant HPAC and PANC-1 cells. Pre-miR-21 transfection or TSA treatment further increased invasion and metastasis ability, decreased PTEN, and elevated pAKT levels in these two lines. In contrast, anti-miR-21 transfection could reverse invasion and metastasis, and PTEN and pAKT expressions induced by gemcitabine. Conclusions: MiR-21 upregulation induced by histone acetylation in the promoter zone is associated with chemoresistance to gemcitabine and enhanced malignant potential in pancreatic cancer cells.
Asian Pacific journal of cancer prevention: APJCP 01/2013; 14(12):7529-36. · 1.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the relationship between serum concentration of fluorouracil and therapeutic efficacy as well as adverse reactions in patients with unresectable locally advanced or measurable metastatic colorectal cancer, and to analyze its role in further improving therapeutic efficacy and reducing adverse reactions of fluorouracil-based chemotherapy.
Eighty-six patients were randomly assigned into three groups according to the average plasma concentration of fluorouracil after three cycles of chemotherapy with the initial regimen of two weeks FOLFOX-4 (oxaliplatin + leucovorin + fluorouracil) or FOLFIRI (irinotecan + leucovorin + fluorouracil): group 1 (plasma concentration of fluorouracil < 25 ng/ml), group 2 (25 - 35 ng/ml) and group 3 (> 35 ng/ml). The blood samples were taken at 12 h after continuous infusion of fluorouracil in each cycle and the plasma concentration of fluorouracil was detected by high performance liquid chromatography (HPLC) (about 5 am ± 1 h). The relationship between the drug plasma concentration, therapeutic efficacy and adverse reactions in different fluorouracil plasma concentration arms was analyzed retrospectively.
The average plasma concentrations of fluorouracil of the three groups were (23.48 ± 1.95) ng/ml, (31.47 ± 2.33) ng/ml and (39.89 ± 3.87) ng/ml, respectively (P < 0.01). As for therapeutic efficacy, the median OS of the groups 2 and 3 were 18.0 and 17.5 months, significantly higher than that in the group 1 (13.0 months, P < 0.01). The PFS were 4.5, 7.5 and 8.0 months, respectively (P < 0.01). In terms of adverse reactions, the incidences of bone marrow suppression, mucositis and diarrhea in the group 3 were significantly higher than that in the first two groups (P = 0.02, P = 0.04 and P = 0.02).
The patients with local advanced and metastatic colorectal cancer, receiving fluorouracil-based chemotherapy, and with an average plasma concentration of fluorouracil between 25 - 35 mg/L have a better prognosis, and lower incidence of adverse reactions such as bone marrow suppression, mucositis and diarrhea.
Zhonghua zhong liu za zhi [Chinese journal of oncology] 01/2012; 34(1):39-43.