[miR-21 promotes pulmonary fibrosis in rats via down-regulating the expression of ADAMTS-1].

Objective To observe the effect of miR-21 on bleomycin-induced pulmonary fibrosis in rats, and explore the related mechanism. Methods Peripheral blood was collected from idiopathic pulmonary fibrosis (IPF) patients (n=20) and healthy adults (n=20). Fluorescence quantitative real-time PCR was then used to measure miR-21 expression. Forty-five SD rats were randomly divided into control group, miR-21 agomir group and miR-21 antagomir group. Each group included 15 rats. After establishment of pulmonary fibrosis models by intratracheal administration with bleomycin A5, rats in control group, miR-21 agomir group and miR-21 antagomir group were injected at caudal vein with normal saline, miR21 agomir and miR21 antagomir, respectively. All rats were sacrificed on day 28 after modeling. Subsequently, the pulmonary tissues were removed for HE and Masson staining. The mRNA and protein expressions of a disintegrin-like and metalloproteinase with thrombospondin type 1 motif (ADAMTS-1), collagen type 1 (Col1) and collagen type 3 (Col3) were detected by fluorescence quantitative real-time PCR and Western blotting. Serum was separated to examine procollagen type 1 carboxyterminal propeptide (P1CP) and procollagen type 3 aminoterminal propeptide (P3NP) concentrations by ELISA. Results The level of miR-21 in peripheral blood was higher in IPF patients than in healthy adults. The alveolitis and pulmonary fibrosis extent in miR-21 agomir group was heavier than that in the control group. However, the alveolitis and pulmonary fibrosis extent in miR-21 antagomir group was improved when compared with the control group. In comparison with the control group, ADAMTS-1 mRNA and protein expression was significantly downregulated, whereas the mRNA and protein expressions of Col1 and Col3 were significantly upregulated and serum P1CP and P3NP concentrations were elevated in miR-21 agomir group. On the contrary, the level of ADAMTS-1 mRNA and protein expression in miR-21 antagomir group was higher than that in the control group; the levels of Col1 and Col3 mRNA and protein as well as serum P1CP and P3NP concentrations in miR-21 antagomir group were lower than those in the control group. Conclusion miR-21 promotes the progression of bleomycin-induced pulmonary fibrosis in rats. The mechanism is associated with downregulation of ADAMTS-1 expression and subsequent increase of pulmonary Col1 and Col3 contents.

[Inhibitory effects of suramin on growth of transplanted lung adencarcinoma in mice and its mechanisms].

BACKGROUND & OBJECTIVE: Recent study found that suramin could inhibit the growth of malignant tumors, but its in vivo effect on lung adenocarcinoma has seldom been reported. This study was to investigate the inhibitory effects of suramin on the growth and metastasis of transplanted lung adenocarcinoma in mice, and explore the mechanisms. METHODS: Lung adenocarcinoma LA795 cells were transplanted into 32 T739 mice. The tumor-bearing mice were randomized into control group, cisplatin (DDP) group, suramin group, and combination (suramin plus DDP) groupû each group contained 8 mice. Different treatments were served since Day 4 after transplantation. All mice were killed 24 days after transplantation. The metastatic tumor foci on the lung in mice were counted. The occurrence rate of lung metastasis and the inhibition rate of metastatic foci were calculated. The volume and weight of tumors were measured. The expression of epidermal growth factor receptor (EGFR), P-selectin and proliferating cell nuclear antigen (PCNA) in tumor tissues were detected by immunhistochemistry. RESULTS: DDP and suramin used alone or in combination significantly inhibited the growth of LA795 cells in mice (P<0.05), with growth inhibition rates of 34.9%, 23.8% and 57.3%, respectively. The occurrence rate of lung metastasis and the number of metastatic foci on lung surface were significantly lower in suramin group and combination group than in DDP group and control group (P<0.05). The protein levels of EGFR and P-selectin were significantly higher in control group than in DDP group, suramin group, and combination group (157.7+/-6.1 vs. 130.7+/-5.9, 110.3+/-5.8, and 89.2+/-5.4, P<0.05û 134.5+/-5.7 vs. 117.9+/-5.1, 96.2+/-5.4, and 78.3+/-4.5, P<0.01). The S phase fraction of tumor cells was significantly higher in control group than in DDP group, suramin group, and combination group [(89.7+/-3.8)% vs. (68.8+/-4.0)%, (65.2+/-4.2)%, and (51.3+/-4.2)%, P<0.01)]. CONCLUSION: Suramin could inhibit the proliferation and metastasis of LA795 cells in T739 mice through regulating the expression of EGFR, P-selectin and PCNA.