Bevacizumab Combined with Icotinib Overcomes Osimertinib Resistance in a Patient of Non-Small Cell Lung Cancer / 中国医学科学杂志(英文版)

A 61-year-old Chinese woman was diagnosed as primary pulmonary adenocarcinoma of left superior lobe with epidermal growth factor receptor (EGFR) 19 del mutation positive. Treatment with icotinib was given, but her disease progressed after 6 months remission. CT-guide needle biopsy for the new lesion in inferior lobe of left lung demonstrated intrapulmonary metastasis, and EGFR gene panel by Amplification Refractory Mutation System Polymerase Chain Reaction (ARMS-PCR) confirmed EGFR T790M mutation. Treatment with osimertinib was initiated. After 2 months remission, the disease progressed. Re-biopsy was performed for the tumor in the inferior lobe of left lung, and ARMS-PCR demonstrated no other gene mutation except EGFR 19 del. Icotinib was re-challenged, but disease progressed continuously. Bevacizumab was added, and partial response was achieved after 2-cycle of combination therapy. The non-small cell lung cancer (NSCLC) in this case maintained EGFR activating mutation and lost EGFR T790M mutation was a genetic change after osimertinib treatment. This case suggests the re-challenge of the first-generation EGFR-TKIs combined with bevacizumab may overcome the tumor resistance and prolong survival of NSCLC patient.

Relationship between epidermal growth factor receptor gene expression and radiosensitivity of non-small-cell lung cancer cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the relationship between epidermal growth factor receptor (EGFR) gene expression and radiosensitivity of non-small-cell lung cancer (NSCLC) cells.</p><p><b>METHODS</b>EGFR sequence-specific double-stranded RNA (dsRNA-EGFR) was chemically synthesized. NSCLC cell line SPC-A1 was transfected with dsRNA-EGFR formulated with Lipofectamine 2000. Western blot and real-time PCR were used to determine the EGFR mRNA and protein expression, respectively. Colony inhibition test was adopted to observe the radiosensitizing effect. To establish the nude mouse tumor models, calculate the tumor growth inhibition rate and make the tumor growth curve by measuring its size and weight.</p><p><b>RESULTS</b>EGFR mRNA levels were 1.51 ± 0.22, 1.38 ± 0.15 and 0.45 ± 0.11 in the control group, dsRNA-unrelated group and dsRNA-EGFR group, respectively (F = 482.7, P < 0.01). The contents of EGFR protein were 2340.87 ± 10.99, 2231.85 ± 35.66 and 832.03 ± 39.13 in the control group, dsRNA-unrelated group and dsRNA-EGFR group, respectively (F = 263.3, P < 0.05). Compared with the control group, dsRNA-EGFR sequence specifically decreased the expressions of EGFR mRNA by 70.2% and EGFR protein by 64.5%. The colony inhibition rates of the control group, dsRNA-unrelated combined with radiotherapy group and dsRNA-EGFR combined with radiotherapy group were 9.3%, 12.5% and 65.5%, and the tumor growth inhibition rates were 21.3%, 24.4% and 64.2%, respectively. The combination of dsRNA-EGFR and radiotherapy significantly inhibited the tumor growth in vitro and in vivo.</p><p><b>CONCLUSIONS</b>DsRNA-EGFR shows an apparent inhibitory effect on the expression of EGFR mRNA and protein of NSCLC cells, effectively inhibit the tumor growth in vivo, and enhance the radiosensitivity of NSCLC.</p>