Huafang Su

Reverse resistance to radiation in KYSE-150R esophageal carcinoma cell after epidermal growth factor receptor signal pathway inhibition by cetuximab

BACKGROUND AND PURPOSE The purpose of our study is to examine the capacity of cetuximab to reverse radiation resistance and investigate molecular mechanisms in human radiation-resistant esophageal carcinoma cell line KYSE-150R. MATERIALS AND METHODS The radioresistant cell line KYSE-150R was established by using fractionated irradiation (FIR). The KYSE-150R cell line was exposed to radiation, treatment with cetuximab, and combined treatment. Cell cycle distribution and apoptosis were analyzed using flow cytometry. Radiation survival was analyzed using clonogenic assays. RT(2) profiler PCR array was performed to analyze EGF/PDGF signaling pathway genes. RESULTS The established esophageal carcinoma cell line KYSE-150R showed higher radioresistance than parental cell line. Cetuximab could reverse the radiation resistance of KYSE-150R cells. Cell cycle analysis showed that combination with radiation and cetuximab resulted in the accumulation of cells in G1 and G2/M phases, with the reduction of cells within the S phase. Cetuximab enhanced the apoptosis induced by radiation. RT(2) profiler array showed that some intracellular signaling genes deriving from EGF/PDGF signaling pathway regulated by cetuximab. CONCLUSIONS Irradiation combined with EGFR blocked by cetuximab may reverse the resistance to radiation in radioresistant esophageal carcinoma cell. The mechanisms may include cell cycle perturbation and enhancement of radiation-induced apoptosis. Further studies are needed to evaluate the role of cetuximab in combination with radiotherapy in the management of esophageal carcinoma.

FH535 increases the radiosensitivity and reverses epithelial-to-mesenchymal transition of radioresistant esophageal cancer cell line KYSE-150R

BackgroundAcquired radioresistance has significantly compromised the efficacy of radiotherapy for esophageal cancer. The purpose of this study is to investigate the roles of epithelial-mesenchymal transition (EMT) and the Wnt/β-catenin signaling pathway in the acquirement of radioresistance during the radiation treatment of esophageal cancer.MethodsWe previously established a radioresistant cell line (KYSE-150R) from the KYSE-150 cell line (a human cell line model for esophageal squamous cell carcinoma) with a gradient cumulative irradiation dose. In this study, the expression of EMT phenotypes and the Wnt/β-catenin signaling pathway proteins were examined by real-time PCR, western blot and immunofluorescence in the KYSE-150R cells. The KYSE-150R cells were then treated with a β-Catenin/Tcf inhibitor FH535. The expressions of nuclear and cytoplasmic β-catenin and EMT markers in KYSE-150R cells were assessed at both mRNA and protein level after FH535 treatment. The radiosensitization effect of FH535 on KYSE-150R was evaluated by CCK8 analysis and a colony forming assay. DNA repair capacities was detected by the neutral comet assays.ResultsKYSE-150R cell line displayed obvious radiation resistance and had a stable genetic ability. EMT phenotype was presented in the KYSE-150R cells with decreased E-cadherin and increased snail and twist expressions. The up-regulated expressions of Wnt/β-catenin signaling pathway proteins (Wnt1, FZD1-4, GSK3β, CTNNB1 and Cyclin D1), the increased phosphorylation of GSK3β, and the decreased phosphorylation of β-catenin were observed in KYSE-150R cells compared with KYSE-150 cells, implicating the activation of the Wnt pathway in KYSE-150R cells. The expression of nuclear β-catenin and nuclear translocation of β-catenin from the cytoplasm was decreased after FH535 treatment. FH535 also reversed EMT phenotypes by increasing E-cadherin expression. The cell proliferation rates of KYSE-150R were dose-dependent and the radiation survival fraction was significantly decreased upon FH535 treatment. Neutral comet assays indicated that FH535 impairs DNA double stranded break repair in KYSE-150R cells.ConclusionsAcquisition of radioresistance and EMT in esophageal cancer cells is associated with the activation of the Wnt/β-catenin pathway. EMT phenotypes can be reduced and the radiosensitivity of esophageal cancer cells can be enhanced by inhibiting the Wnt/β-catenin pathway with FH535 treatment.

Treatment outcome comparisons between exons 19 and 21 EGFR mutations for non-small-cell lung cancer patients with malignant pleural effusion after first-line and second-line tyrosine kinase inhibitors

Recent studies demonstrated a significantly increased frequency of epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer (NSCLC) patients with malignant pleural effusions (MPEs). The purpose of this study is to investigate the effect of first-line and second-line EGFR-tyrosine kinase inhibitors (TKIs) in the treatment of NSCLC with MPEs harboring exon 19 deletion and L858R mutation. From 2010 to 2015, 203 NSCLC patients with MPEs harboring EGFR mutation treated with EGFR-TKIs were reviewed. The efficacy were evaluated with Pearson chi-square or Fisher’s exact tests, Log-rank test and Cox proportional hazards model. The objective response rate (ORR) and disease control rate (DCR) for patients treated with first-line and second-line EGFR-TKIs were 21.9%, 91.4% and 14.7%, 85.3%, respectively. The overall median PFS and OS of enrolled NSCLC patients with MPE were 9.3 months (95% CI, 8.4–10.2 months), 20.9 months (95% CI, 18.9–22.9 months) after first-line TKIs, and 7.6 months (95% CI, 6.6–8.6 months), 15.3 months (95% CI, 13.6–15.9 months) after second-line TKIs. The exon 19 deletion arm had a longer median PFS (9.4 vs 7.1 months, p=0.003) and OS (16.8 vs 13.8 months, p=0.003) compared with the L858R mutation arm after second-line TKIs. In a conclusion, EGFR genotype was an independent predictor of PFS and OS. No significant side effects differences between the two mutation groups was observed for first or second-line EGFR-TKIs. This study demonstrated that EGFR mutations are significant predictors for advanced NSCLC patients with MPE receiving second-line EGFR-TKIs treatment.

Simultaneous Modulated Accelerated Radiation Therapy and Concurrent Weekly Paclitaxel in the Treatment of Locally Advanced Nasopharyngeal Carcinoma

OBJECTIVES To evaluate the feasibility and efficacy of simultaneous accelerated radiation therapy (SMART) and concurrent weekly paclitaxel in the treatment of locally advanced nasopharyngeal carcinoma. METHODS Forty- one patients with pathologically confirmed nasopharyngeal carcinoma were treated by SMART with concurrent weekly paclitaxel. Daily fraction doses of 2.5 Gy and 2.0 Gy were prescribed to the gross tumor volume (GTV) and clinical target volume (CTV) to a total dose of 70 Gy and 56 Gy, respectively. Paclitaxel of 45 mg/m2 was administered concurrently with radiation therapy every week. Adjuvant chemotherapy was given four weeks after the completion of the radiotherapy (RT) if the tumor demonstrated only a partial response (PR). RESULTS All patients completed the radiotherapy (RT) course. Adjuvant chemotherapy was administered to 12 patients due to PR. The CR (complete remission) rate was 82.9% three months after RT. Thirty-nine (95.1%) patients completed the concurrent weekly chemotherapy with paclitaxel, and two patients skipped their sixth course. Seven patients had a 15% dosage reduction at the fifth and sixth course due to grade 3 mucositis. The median follow-up was 30 (range, 14-42) months. The three-year overall survival (OS), metastases-free survival (MFS), and local control rates were 77.0%, 64.4%, and 97.6%, respectively. No correlation between survival rate and T or N stage was observed. Grade 3 acute mucositis and xerostomia were present in 17.1% and 7.1%, respectively. CONCLUSION SMART with concurrent weekly paclitaxel is a potentially effective and toxicity tolerable approach in the treatment of locally advanced NPC.