Reuse of osimertinib after small cell lung cancer transformation in lung adenocarcinoma with de-novo epidermal growth factor receptor T790M mutation: case report.

Osimertinib is a third-generation tyrosine kinase inhibitor for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-sensitizing mutations and acquired drug-resistant mutation T790M. Despite promising treatment benefits of osimertinib in first- and second-line settings, drug resistance has been an inevitable clinical issue. The resistance to osimertinib is heterogeneous, which may involve EGFR-dependent and independent mechanisms as well as histological transformation from NSCLC to small cell lung cancer (SCLC). Current clinical studies of NSCLC were mainly focused on patients with EGFR-sensitizing mutations or acquired T790M mutation or both. The treatments and drug-resistant mechanisms in patients with de-novo T790M mutation remain undefined. Herein, we reported the presence of the less common de-novo EGFR T790M mutation in a stage IV NSCLC patient. The patient received osimertinib as first-line treatment and achieved durable progression-free survival (PFS) for 24 months. After osimertinib resistance, tumor biopsy indicated histologic transformation from NSCLC to SCLC. Given persistent presence of de-novo T790M mutation, osimertinib was used in combination with etoposide and cisplatin as second-line treatment and the patient achieved partial response with PFS of 7 months. Our study suggested that NSCLC patients with de-novo T790M mutation could also benefit from osimertinib and the SCLC transformation may be a potential resistance mechanism that could be targeted through the combination of targeted therapy and chemotherapy.

Preliminary Clinical Validation of a Filtration-Based CTC Assay for Tumor Burden and HER2 Status Monitoring in Metastatic Breast Cancer.

BACKGROUND: Bearing multidimensional tumor-relevant information ranging from genomic alterations to proteomic makeup, circulating tumor cells (CTCs) constitute a promising material for liquid biopsy. The clinical validity of CTCs has been most extensively studied in metastatic breast cancer (MBC). The Cellsearch assay is currently the most widely used, while alternative strategies are pursued. A filtration-based microfluidic device has been described for CTC enrichment, but its clinical relevance remains unknown. METHODS: In this preliminary study, we prospectively enrolled 47 MBC patients and evaluated the performance of the abovementioned CTC assay for tumor burden monitoring and human epidermal growth factor receptor 2 (HER2) status determination. RESULTS: At baseline, 51.1% patients (24/47) were CTC positive. CTC count and positivity were also significantly higher in samples that accompanied poorer radiographic response evaluations. Serial blood draws suggested that CTC count enabled more accurate monitoring of tumor burden than serum markers carcinoembryonic antigen and cancer antigen 15-3. Also, in contrast to previous reports, CTC-HER2 status was moderately consistent with tumor-HER2 status. CTC-HER2 status assessment was further supported by HER2 copy number measurements in select samples. CONCLUSION: The preliminary results from this study suggest promise for the interrogated CDC assay in several aspects, including sensitive CTC detection, accurate disease status reflection, and HER2 status determination. More studies are warranted to validate these findings and further characterize the value of CTC assay.

Targeting H19 by lentivirus-mediated RNA interference increases A549 cell migration and invasion.

BACKGROUND: Lung cancer is one of the most common and a lethal malignancy in the world and non-small cell lung cancer (NSCLC) is the most usual type. H19 long non-coding RNA (lncRNA) plays essential roles in tumor development. But its role in tumor metastasis is still unclear. MATERIALS AND METHODS: MACC1 RNAi and Lentivirus-mediated H19-specific shRNA was used to establish H19 stable knocking-down A549 cells. Transwell assays were performed to examine the effect of H19 knocking-down on A549 cells migration and invasion. The downstream signaling proteins targeted by H19 were also examined by western blot. AG1478 and U0126 were used as the inhibitor of EGFR and ERK1/2, respectively. RESULTS: The knockdown of H19 increased the migration and invasion of A549 cells, and knockdown of metastasis-associated in colon cancer 1 (MACC1) decreased the migration and invasion of A549 cells. Furthermore, MACC1 protein targeted by H19 was upregulated as well as the downstream signaling proteins including epidermal growth factor receptor (EGFR), ß-catenin, extracellular-signal-regulated kinase 1/2 (ERK1/2). Inhibited the expression of EGFR or ERK1/2 significantly decreased the migration and invasion of tumor cells. CONCLUSION: Our findings showed that H19 functions as a suppressor of NSCLC and plays an important role in the migration and invasion of NSCLC. More importantly, H19 may regulate NSCLC metastasis through modulating cellular signaling pathway proteins related to cell proliferation and cell adhesion, including MACC1, EGFR, ß-catenin and ERK1/2. These results put forward our understanding of the detailed mechanism of H19 lncRNA regulating the process of NSCLC metastasis.

[Gefitinib versus Erlotinib as first-line treatment for patients with advanced EGFR mutation-positive non-small-cell lung cancer].

OBJECTIVE: To compare the efficacy of the erlotinib versus gefitinib in the first-line treatment of patients with advanced EGFR mutation-positive NSCLC. METHODS: Fifty patients with untreated advanced EGFR mutation- positive NSCLC were randomly divided into gefitinib group (n=27) and erlotinib group (n=23). The progression-free survival, objective response rate and disease control rate were evaluated to compare the efficacy of gefitinib and erlotinib. RESULTS: There were no significant differences in the objective response rate (P=0.711) and disease control rate (P=0.861) between the two groups. The progression-free survival of gefitinib group and erlotinib group was 8.0 months and 10.0 months, respectively. The efficacy of the two drugs was similar (P=0.293). CONCLUSION: There is no significant differences between gefitinib and erlotinib in the first-line treatment of patients with advanced EGFR mutation-positive NSCLC.

Reversal effect of BM-cyclin 1 on multidrug resistance by down-regulating MRP2 in BALB/C nude mice bearing C-A120 cells.

Our previous study demonstrated that BM-cyclin 1, a traditional anti-mycoplasma drug, could effectively reverse the multidrug resistance (MDR) of C-A120 cells. The present study aims to explore the reversal effect of BM-cyclin 1 on MDR and its mechanisms in BALB/C nude mice bearing C-A120 cells. Immunoblotting analysis and reverse transcription-polymerase chain reaction (RT-PCR) were used to study the change in multidrug resistance-associated protein 2 (MRP2) induced by BM-cyclin 1. We found that the expression levels of MRP2 protein and mRNA in C-A120 cells treated with BM-cyclin 1 were reduced significantly. Chemical colorimetry revealed no significant change in the level of glutathione (GSH). In the xenograft model, the inhibitory rate of C-A120 cells growth in BM-cyclin 1 plus adriamycin (ADM) group was 52%, which was significantly higher than in control group (P<0.01). The immunoblotting and RT-PCR results conclusively demonstrated that BM-cycin 1 could significantly reduce the expression of MRP2 in transplanted tumor. In conclusion, BM-cyclin 1 could effectively reverse the MDR of C-A120 cells in vivo by suppressing the expression of MRP2.

[Inhibitory effect of SHP-1 gene transfer on the proliferation of breast cancer cell line MDA-MB-231].

OBJECTIVE: To observe SHP-1 protein expression in breast cancer cell line MDA-MB-231 before and after SHP-1 gene transfer and its effect on the proliferation of MDA-MB-231 cells. METHODS: The eukaryotic expression vector pEGFP-C3-SHP-1 was constructed and transfected into breast cancer cell line MDA-MB-231 via Lipofectamine 2000, and the positive clones were selected using G418. SHP-1 expression in MDA-MB-231 cells was detected with immunocytochemistry and Western blotting, and the cell growth curve was observed using MTT assay. RESULTS: SHP-1 was highly expressed in transfected MDA-MB-231 cells, whose proliferation was significantly inhibited (P<0.05). CONCLUSION: SHP-1 gene transfer into MDA-MB-231 cells results in inhibition of the cell proliferation.

[Retrovirus-mediated SHP-1 gene expression in human breast cancer MDA-MB-231 cells].

OBJECTIVE: To construct a retrovirus-mediated expression system carrying human SHP-1 gene to transfer SHP-1 gene in human breast cancer MDA-MB-231 cells. METHODS: The full-length SHP-1 gene fragment was amplified by RT-PCR from the total RNA extracted from human breast cancer cell line MCF-7 over-expressing SHP-1 protein. The gene fragment was inserted into the vector pLNCX2 to construct the recombinant retroviral plasmid, which was transfected into the packaging cell PT67 via Lipofectamine2000. A cell line stably producing the virus was selected with G418. MDA-MB-231 cells was infected with the virus, and the expression of SHP-1 gene in the positive cell clone was detected with Western blotting. RESULTS: A 1.8 kb cDNA fragment of SHP-1 gene was obtained from MCF-7 cells and successfully inserted into the pLNCX2. A stable cell clone PT67/SHP-1 and virus supernatant were obtained. Expression of SHP-1 protein was detected in the cells infected with the virus. CONCLUSION: The recombinant retroviral vector carrying SHP-1 gene has been successfully constructed and MDA- MB-231/SHP-1 cell line expressing SHP-1 has been obtained to allow further functional study of SHP-1 in breast cancer.