Study Of The Application Of The Osteopontin In The Diagnosis And Treatment Of The Hepatocellular Carcinoma

【Objective】To investigate the expression of osteopontin (OPN) and its correlationwith clinicopathological variables in hepatocellular carcinoma (HCC); toevaluate the clinical application of serum OPN level as a biomarker for HCCand to study the effect of anti-OPN antibodies on inhibiting tumor growth,metastasis and angiogenesis in HCCML3tumors and their promoting effect onthe radiotherapy of HCCLM3tumors.【Methods】1. Part one: Immunohistochemistry technique was used to detect theexpression of OPN in70primary HCC tissues,15liver cirrhosis tissues and10normal liver tissues.2. Part two: plasma levels of osteopontin (OPN) and Alpha-fetoprotein(AFP) were measured from70HCC patients,65patients with chronic liverdiseases (CLD) and65healthy control individuals using standard ELISA kits.3. Part three: HCCLM3were inoculated subcutaneously into the back of74Balb/c nude mice.1d after inoculation,50mice were randomized into fivegroups (10mice per group) according to different treatment: Group A (treatedwith normal Saline), Group B (treated with non-specific antibody), Group C, Dand E (treated with5mg/kg,10mg/kg, and20mg/kg of the anti-OPN antibodies,respectively). The treatments were repeated twice per week and tumor volume was measured every other day.10w later, tumors and lungs of the mice werecollected and carried on histopathologic examination. Microvessel density(MVD) was measured by immunhistochemical method. The other24nudemice bearing HCC tumors were randomly divided into four groups: Controlgroup (treated with normal Saline), Radiation group (treated with6MeVelectron ray on the tumor), Antibodies group (treated with20mg/kg anti-OPNantibody), Combination group (treated with20mg/kg anti-OPN antibody and6MeV electron ray on the tumor). The tumor volume was measured every dayand the enhancement factor (EF) was used to evaluate the radiationenhancement.【Results】1. The rate of OPN expression was significantly higher in tissues fromHCC than in tissues from liver cirrhosis and normal liver (P﹤0.001). And theoverexpression of OPN was significantly correlated with capsular infiltration(P=0.044) and early recurrence and metastasis (P=0.003).2. Significantly higher plasma OPN levels (median975ng/mL,range131-5920ng/mL)(P <0.001) were found in the HCC patients than inpatients with CLD (352ng/mL, range18-1875ng/mL) or healthy control(median103ng/mL,8-984ng/mL). Within the HCC patient group, plasma OPNlevel increased with the increasing of Child-Pugh class and of tumor stage.And the plasma OPN level was significantly correlated with capsular infiltration(P<0.05). Diagnostic sensitivity and specificity of OPN for HCC was87.1%and75.4%, respectively (cut-off value:617.6ng/mL). OPN had a greater areaunder curve value (0.872) than AFP (0.817)(P<0.01).3. Single dose of5mg/kg,10mg/kg and20mg/kg of anti-OPN antibodyhad significant inhibiting effect on the tumor growth (P﹤0.01), metastasis (P﹤0.05), and angiogenesis (P﹤0.05) when compared to controls. The inhibitionrate of tumor growth in combination group I (41.67%) was higher than that ofboth antibody group (11.86%) and radiation group (24.04%)(P﹤0.01). 【Conclusion】1. Overexpression of OPN is common in HCC and is closely related withcapsular infiltration and early recurrence and metastasis.2. Our results suggest that plasma OPN level may be a potentialdiagnostic marker for HCC.3. The anti-OPN antibody can inhibit the tumor growth, metastasis, andangiogenesis and promote radiotherapy effect on HCC tumors in mice, whichmay be a promising therapeutic agent for the treatment of HCC.