Molecular mechanism of chemosensitization to paclitaxel in human melanoma cells induced by targeting the EGFR signaling pathway / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the molecular mechanism of epidermal growth factor receptor (EGFR) signaling pathway in mediating paclitaxel-resistance and improving paclitaxel sensitivity in human melanoma A375 cells.</p><p><b>METHODS</b>Human melanoma cell line A375 cells were treated with different concentrations of paclitaxel with or without 20 µmol/L AG1478 (EGFR inhibitor), 40 µmol/L PD98059 (extracellular signal conditioning kinase (ERK) 1/2 blockers) or 10 µmol/L LY294002 (PI3K inhibitor). MTT method was used to measure the proliferation of A375 cells. Flow cytometry was used to detect cell cycle and apoptosis in the A375 cells. The expressions of P-EGFR, P-ERK and P-AKT proteins were determined by Western blot analysis.</p><p><b>RESULTS</b>Paclitaxel (0.001 µmol/L to 0.1 µmol/L) inhibited the growth of A375 cells (P < 0.01) and induced apoptosis (P < 0.05) in a dose- and time-dependent manner. AG1478 (20 µmol/L) increased the 0.01 µmol/L paclitaxel-induced inhibition rate from 38.5% to 62.6% at 72 h. Different doses of paclitaxel induced apoptosis in A375 cells by different ways, in which G0/G1 phase cells were decreased and mitotic phase was prolonged at 0.01 µmol/L, and cell cycle arrest at G2/M phase by 0.1 µmol/L paclitaxel. When DNA damage occurred in A375 cells exposed to paclitaxel, expression of P-EGFR, P-ERK and P-AKT proteins was increased. When EGFR signaling pathway was blocked, paclitaxel did not activate MAPK signaling pathway or PI3K/AKT signaling pathway and did not change its effect on cell cycle in vitro. When EGFR was inhibited by 20 µmol/L tyrophostin AG1478, the 0.001 and 0.01 µmol/L paclitaxel-induced early apoptosis rate in A375 cells was increased by 1.73- and 1.80-fold, respectively. When the ERK signaling was blocked by 40 µmol/L PD98059, the 0.001 and 0.01 µmol/L paclitaxel-induced early apoptosis rate in A375 cells was increased by 2.73- and 2.25-fold, respectively. When the AKT signaling was blocked by 10 µmol/L LY294002, the 0.001 and 0.01 µmol/L paclitaxel-induced early apoptosis rate in A375 cells was increased by 2.02- and 1.46-fold, respectively.</p><p><b>CONCLUSIONS</b>Human melanoma A375 cells produce resistance to paclitaxel (0.001 to 0.1 µmol/L) by activating MAPK signaling and PI3K/AKT signaling pathways. Targeting EGFR, ERK and AKT signaling pathways significantly enhances the cytotoxic effect of paclitaxel on human melanoma cells.</p>

Isolated limb hyperthermic perfusion chemotherapy for melanoma of the extremities / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of isolated limb hyperthermic perfusion chemotherapy for melanoma of the extremities.</p><p><b>METHODS</b>Limb isolated hyperthermic perfusion chemotherapy was performed in 41 patients with malignant melanoma of the extremities, and then the primary lesions in 24 patients were removed at 14 - 21 days after chemotherapy. Tumor necrosis was examined by pathology.</p><p><b>RESULTS</b>Among the 41 patients, 40 cases were followed up for 6-113 months, and one was lost. There was no local recurrence in those patients. 29 cases were followed up for more than 3 years, and 26 of them were surviving. Forteen cases were followed up for more than five years, among them 9 cases were surviving. The 3-year and 5-year survival rates of the whole group were 95.0% and 70.0%, respectively. The average reduction of the tumor volume was 55.6% after perfusion. The pathological examination showed that tumor necrosis was 90% - 100% (complete response) in 21 cases (87.5%) and 60% - 89% (partial response) in 3 cases (12.5%).</p><p><b>CONCLUSIONS</b>The isolated limb hyperthermic perfusion chemotherapy is an effective treatment of limb malignant melanoma. It can significantly reduce the local recurrence rate, and improve the 5-year survival rate, prognosis and the quality of life of the patients.</p>

Cisplatin blood concentration of patients with malignant bone tumor of lower extremity with out discarding blood after hyperthermic antiblastic perfusion / 中华骨科杂志

Objective To explore the possibility of non-discarding blood after cisplatin hyperther-mic antiblastic perfusion(HAP)in treating the patients with malignant bone tumor of lower extremity.Methods Forty patients consisted of 31osteosarcomas and9malignant fibrous histiocytomas of bone.The clinical stages were wholly classified intoⅡB stage according to Ennekings surgical staging system for muscu-loskeletal tumors.The patients were divided into three groups:group1:discarding blood group(10cases),in whom200ml of the400ml blood remaining in heart-lung machine was discarded after HAP;group2:Non-discarding blood group(25cases),the blood remaining in heart-lung machine was not discarded after HAP and re-infused into systemic circulation;group3:systemic chemotherapy group(5cases),cisplatin was infused intravenously.The regional and the systemic blood cisplatin concentrations were determined at3,30and60minutes during HAP,and the systemic blood cisplatin concentrations were determined at0,0.5,1,2,4,8,12,24,48and72hours after HAP in the group1and group2.While1h after cisplatin infusion in-tra venously in the group3,the blood cisplatin concentration were also measured.Results The regional blood cis platin concen tra tions were high er than that in systemic blood at the time during HAP.The systemic blood cisplatin concen trations after HAP,ex cept at0minute in the group2were higher than that in the group1,there were sig nificant statistic differences between the two groups.The systemic blood cisplatin con-cen trations after HAP in the group2were simi lar to that after systemic chemotherapy.No severe adverse ef-fects in the group1were found.The Ennek ings surgical stagings for the tumors were turned fromⅡB intoⅡA in all the patients.Conclusion The method of non-discarding blood after HAP is available,it is not only local treatment ,but also systemic chemotherapy in the patients with malignant bone tumor of lower ex-tremi ty for limb-salvage surgery.