Correction: FGFR1ß is a driver isoform of FGFR1 alternative splicing in breast cancer cells.

[This corrects the article DOI: 10.18632/oncotarget.26530.].

FGFR1ß is a driver isoform of FGFR1 alternative splicing in breast cancer cells.

Abnormal FGFR1 alternative splicing is correlated with tumorigenicity and poor prognosis in several tumor types. We sought to determine the roles of FGFR1α and FGFR1ß variants in breast cancer. TCGA samples and cell lines were analyzed for FGFR1α/FGFR1ß expression. MCF-10A cells were used to overexpress these variants. Cell growth and transformation were assessed by SRB, colony formation, 3D-Matrigel, soft agar, cell motility assays. In TCGA, compared to FGFR1 non-amplified samples, FGFR1-amplified samples had significantly higher FGFR1α but not FGFR1ß levels. FGFR1ß expression levels and FGFR1ß/FGFR1α ratio were higher in basal subtype samples than in ER-positive/luminal samples in both TCGA and breast cancer cell lines. Both FGFR1α and FGFR1ß induced transformation of MCF-10A cells. However, only FGFR1ß-expressing cells, not FGFR1α, enhanced cell growth and cell motility. Cells with higher FGFR1ß levels and FGFR1ß/FGFR1α ratio were more sensitive to FGFR inhibitor BGJ-398. Interestingly, in ER-negative cells, FGFR inhibitors decreased FGFR1ß levels, likely by increasing expression of splicing repressor PTBP1. In ER-positive cells, estrogen treatment increased FGFR1ß levels by decreasing PTBP1 expression, which was blocked by 4-OHT. Lastly, combination treatment with BGJ-398 and 4-OHT synergistically inhibited cell survival. These findings suggest that FGFR1 alternative FGFR1α/FGFR1ß splicing plays an important role in breast cancer.

Rechallenge with pemetrexed-based chemotherapy improves the survival of patients with advanced non-squamous non-small-cell lung cancer.

Rechallenge chemotherapy with pemetrexed was shown to be efficient in malignant pleural mesothelioma; however, its role in non-small-cell lung cancer (NSCLC) has not been investigated. In this study, we retrospectively enrolled 31 patients with non-squamous NSCLC who had achieved disease control with initial pemetrexed treatment, followed by rechallenge with pemetrexed-based chemotherapy (PBC) upon disease progression. After the rechallenge, 5 patients (16.1%) achieved partial remission (PR), 17 (54.8%) achieved stable disease (SD) and 9 (29.1%) experienced progressive disease. The treatment was generally well tolerated, with a low rate of toxicity. The median progression-free survival (PFS) was 3.8 months with the rechallenge. Patients with a PFS of ≥10 months with initial PBC exhibited longer PFS and overall survival (OS) with the rechallenge compared to those with a PFS of <10 months with initial PBC (PFS: 6.2±0.33 vs. 3.1±0.26 months, respectively; P=0.011; and OS, 19.8±3.2 vs. 9.2±1.1 months, respectively; P=0.005). The time from the termination of initial PBC to disease progression was also associated with survival after the rechallenge. However, the response to initial PBC (PR vs. SD) did not affect PFS after the rechallenge. No significant differences were observed in thymidylate synthase expression, echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase gene fusion, or epithelial growth factor receptor mutation status between pemetrexed-sensitive and pemetrexed-resistant patients. Our results demonstrated that rechallenge with PBC was well tolerated and survival after the rechallenge was associated with survival during initial PBC. Therefore, patients with a PFS of ≥10 months or time-to-disease progression ≥3 months may be considered as candidates for pemetrexed rechallenge.

[Prognosis related clinical and molecular factors in malignant pleural mesothelioma].

OBJECTIVE: To identify potential prognosis related clinical and molecular factors in malignant pleural mesothelioma (MPM). METHODS: Seventy-nine patients with MPM treated in Beijing Cancer Hospital from June 1996 to May 2012 were enrolled in this study. Clinical and pathological data were collected, including age, gender, smoking status, treatment, response, and molecular biomarkers such as thymidylate synthetase (TS) expression, echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) gene rearrangement. The primary endpoint was overall survival (OS). SPSS 16.0 statistical analysis software was used for univariate analysis. The expression of TS was detected by immunohistochemistry (IHC). Fluorescence in situ hybridization (FISH) was performed to detect EML4-ALK gene rearrangement. Efficacy of the chemotherapy regimen including pemetrexed was analyzed with these molecular biomarkers. RESULTS: The median survival time (MST) of all patients was 15.5 months (95% CI: 10.6 - 20.4). Univariate survival analysis revealed that treatment factors including receiving operation, systemic chemotherapy, pemetrexed-based chemotherapy and capability of receiving second (or above) line chemotherapy were significantly related with OS. The MST of patients receiving operation was 5.4 months (95% CI: 3.6 - 7.3), significantly shorter than the 17.7months (95% CI: 11.8 - 23.5) in those who didn't receive operation (P = 0.030). Patients receiving systemic chemotherapy had a longer MST of 18.0 months (95% CI: 12.3 - 23.8) as compared to the 7.9 months (95% CI: 1.1 - 14.7) in those who didn't (P = 0.001). The MST of pemetrexed-based chemotherapy was 21.9 months (95% CI: 14.1-29.7) compared with 8.8 months (95% CI: 4.2 - 13.4) of regimens without pemetrexed (P = 0.000). For patients capable of receiving second (or above) line chemotherapy the MST was longer (21.0 months, 95% CI: 12.7 - 29.3) than those who could not (12.1 month, 95% CI: 6.4 - 17.8 month), P = 0.022. For the 42 patients treated with pemetrexed-based chemotherapy, the objective response rate (ORR) was 33.3% (14/42), the disease control rate (DCR) was 78.6% (33/42), the median progression-free survival (PFS) was 4.8 months (95% CI: 3.6 - 6.0) and MST was 21.9 months (95% CI: 14.1 - 29.7). Twenty-nine patients provided adequate specimens for detection of TS expression and 6 cases (20.7%) were positive. EML4-ALK gene rearrangement was studied in 32 patients and 6 (18.8%) were positive. TS expression was found to be inversely related to PFS of pemetrexed-based chemotherapy (P = 0.041). The MST was 19.6 months (95% CI: 6.0 - 7.9) in EML4-ALK-positive patients and 9.57 months (95% CI: 2.7 - 4.3) in negative ones (P = 0.159). CONCLUSIONS: Systemic chemotherapy especially pemetrexed-based regimen was proved to be a superior option for MPM with a significantly prolonged OS. Correlation between TS expression or EML4-ALK rearrangement and outcome of pemetrexed-based chemotherapy for MPM may contribute to future individualized treatment, which needs further validation from large-scale prospective studies.

[Correlation between the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors and EGFR mutations in advanced squamous cell lung cancer].

OBJECTIVE: To investigate the frequency of epidermal growth factor receptor (EGFR) mutations and their correlation with the efficacy of tyrosine kinase inhibitors (EGFR-TKI) in advanced squamous cell lung cancer. METHODS: This retrospective study enrolled 79 patients with advanced squamous cell lung cancer who received EGFR-TKI at Department of Thoracic Medical Oncology in Peking University Cancer Hospital from June 2004 to June 2011. Among them, 67 patients had tissue and/or plasma EGFR exon 19 and 21 mutation detection in order to make an analysis on the relationship between EGFR mutation and the TKI's effect. RESULTS: The disease control rate (DCR) was 56% in all the patients. The median progression free survival (mPFS) and median overall survival (mOS) was 3.7 months (95%CI: 2.0 - 5.0) and 11.5 months (95%CI: 6.6 - 14.2), respectively. Of the 67 patients who received EGFR mutation detection, there were 31 patients harboring EGFR-mutation, for whom the DCR was 71% (22/31), and mPFS and mOS was 6.3 months (95%CI: 2.2 - 10.0) and 13.5 months (95%CI: 7.3 - 18.6) respectively. 36 patients' EGFR status were wild type, for whom the DCR was 44% (16/36), mPFS and mOS was 2.2 months (95%CI: 1.1 - 4.0) and 6.4 months (95%CI: 4.0 - 12.0). There were 17 patients who received erlotinib and 7 patients who received gefitinib as second or more line treatment. mPFS and mOS were 7.9 months and 15.8 months in the erlotinib group, respectively; and the mPFS and mOS were both 6.3 months in gefitinib group; the difference between the 2 groups did not reach statistical significance. Cox-regression analysis showed that EGFR mutation was significantly correlated with PFS and OS (P < 0.05, respectively). EGFR mutation was significantly correlated with DCR by Chi-square test, P < 0.05. CONCLUSIONS: EGFR mutation was a predictor for advanced squamous cell lung cancer to EGFR-TKI. However, the effect was inferior in advanced squamous cell lung cancer as compared to lung adenocarcinoma. Erlotinib tended to be superior to gefitinib.

[Effect of pemetrexed plus platinum for chemotherapy-naive advanced non-small cell lung cancer].

OBJECTIVE: To evaluate the effect of pemetrexed plus platinum for chemotherapy-naive advanced non-small cell lung cancer (NSCLC), and to explore thymidylate synthetase (TS) expression as the predictive and prognostic factor for this treatment. METHODS: This retrospective study enrolled 51 patients with chemotherapy-naive advanced NSCLC (non-squamous) treated at Department of Thoracic Medical Oncology in Beijing Cancer Hospital from Jan 2008 to Oct 2009. All patients received pemetrexed plus platinum as first-line treatment. TS expression was detected in 30 patients who had enough tissue samples by immunohistochemistry. RESULTS: The objective response rate (ORR) was 37.3%. Median progression-free survival (PFS) was 5.3 months (95%CI: 3.9 - 6.7), and median overall survival (OS) was 19.0 months (95%CI: 11.6 - 26.4). Univariate analysis showed that gender, pathology, smoking status and response were significantly correlated with OS. Cox-regression analysis showed that pathology was an independent prognostic factor. Rate of Grade 3/4 adverse events was low. In 30 patients with enough tissue samples were available, TS expression positive rate was 33.3% (10/30). Chi-square test showed that TS expression was not associated with ORR. Multivariate analysis showed that pathology, response and TS expression (P = 0.003, 0.005 and 0.001, respectively) were the prognostic factors. CONCLUSION: The therapeutic effect and tolerance of pemetrexed plus platinum regiment were definite as first-line treatment for chemotherapy-naive advanced NSCLC, and TS expression was an independent prognostic factor.

Epidermal growth factor receptor genotype in plasma DNA and outcome of chemotherapy in the Chinese patients with advanced non-small cell lung cancer.

BACKGROUND: The genotype of epidermal growth factor receptor (EGFR) is associated with tyrosine kinase inhibitor and effectiveness of therapy, but its role in cytotoxic chemotherapy is still unknown. Previous studies indicated that certain EGFR mutations were associated with response and progression free survival following platinum based chemotherapy. Our recent studies have identified that EGFR genotypes in the tumour tissues were not associated with response to the first-line chemotherapy in Chinese patients with advanced non-small cell lung cancer (NSCLC). In this study, we investigated associations of EGFR genotypes from plasma of patients with advanced NSCLC and response to first-line chemotherapy and prognosis. METHODS: We enrolled 145 advanced NSCLC patients who had received first-line chemotherapy in our department. We examined plasma EGFR genotypes for these patients and associations of EGFR mutations with response to chemotherapy and clinical outcomes. RESULTS: There were 54 patients with known EGFR mutations and 91 cases of wild types. No significant difference was detected in the response rate to first-line chemotherapy between mutation carriers and wild-type patients (37.0% vs. 31.9%). The median survival time and 1-, 2-year survival rates were higher in mutation carriers than wild-types (24 months vs. 18 months, 85.7% vs. 65.7% and 43.7% vs. 25.9%, P = 0.047). Clinical stage (IV vs. IIIb), response to the first-line chemotherapy (partial vs. no) and EGFR genotype were independent prognostic factors. CONCLUSION: Plasma EGFR mutations in the Chinese patients with advanced NSCLC is not a predictor for the response to first-line chemotherapy, but an independent prognostic factor indicating longer survival.

Endothelium-specific overexpression of human IC53 downregulates endothelial nitric oxide synthase activity and elevates systolic blood pressure in mice.

AIMS: Hypertension is one of the major risk factors for cardiovascular diseases. Endothelial cells (ECs) exert important functions in the regulation of blood pressure. A novel gene, IC53, as an isoform of the cyclin-dependent kinase (CDK)-binding protein gene C53, is mainly expressed in vascular ECs and is upregulated in the failing heart of rats. Overexpression of IC53 promotes proliferation of ECs. To examine whether IC53 plays a role in the regulation of vascular tone and blood pressure, we constructed a transgenic (tg) mouse model of the IC53 gene and studied its phenotypes relevant to vascular function. METHODS AND RESULTS: IC53 cDNA was cloned from a human aorta cDNA library. Using the endothelium-specific VE-cadherin promoter, we constructed tg mice in which IC53 was specifically overexpressed in vascular endothelia and found that the tg mice exhibit elevated systolic blood pressure (SBP) in contrast to the wild-type (wt) controls. Further studies revealed impaired endothelium-dependent vasodilation, reduced nitric oxide (NO) production and decreased endothelial NO synthase (eNOS) expression, and activity in the tg mice. Inhibition of IC53 in human umbilical vein ECs induces upregulation of eNOS activity. CONCLUSION: Our results indicate that IC53 participates in the regulation of vascular homeostasis. Endothelium-specific overexpression of IC53 is associated with elevated SBP, which may be in part attributed to the downregulation of eNOS signalling.

Targeted cardiac overexpression of A20 improves left ventricular performance and reduces compensatory hypertrophy after myocardial infarction.

BACKGROUND: A20 was originally characterized as a tumor necrosis factor-inducible gene in human umbilical vein endothelial cells. As an inhibitor of nuclear factor-kappaB signaling, A20 protects against apoptosis, inflammation, and cardiac hypertrophy. In the present study, we tested the hypothesis that cardiac-specific overexpression of A20 could protect the heart from myocardial infarction. METHODS AND RESULTS: We investigated the role of constitutive human A20 expression in acute myocardial infarction using a transgenic model. Transgenic mice containing the human A20 gene under the control of the alpha-myosin heavy chain promoter were constructed. Myocardial infarction was produced by coronary ligation in A20 transgenic mice and control animals. The extent of infarction was then quantified by 2-dimensional and M-mode echocardiography and by molecular and pathological analyses of heart samples in infarct and remote heart regions 7 days after myocardial infarction. Constitutive overexpression of A20 in the murine heart resulted in attenuated infarct size and improved cardiac function 7 days after myocardial infarction. Significantly, we found a decrease in nuclear factor-kappaB signaling and apoptosis, as well as proinflammatory response, cardiac remodeling, and interstitial fibrosis, in noninfarct regions in the hearts of constitutive A20-expressing animals compared with control animals. CONCLUSIONS: Cardiac-specific overexpression of A20 improves cardiac function and inhibits cardiac remodeling, apoptosis, inflammation, and fibrosis after acute myocardial infarction.

KATP channel: relation with cell metabolism and role in the cardiovascular system.

ATP-sensitive potassium channel (K(ATP)) is one kind of inwardly rectifying channel composed of two kinds of subunits: the pore forming subunits and the regulatory subunits. K(ATP) channels exist in the sarcolemmal, mitochondrial and nuclear membranes of various tissues. Cell metabolism regulates K(ATP) gene expression and metabolism products regulate the channel by direct interactions, while K(ATP) controls membrane potentials and regulate cell activities including energy metabolism, apoptosis and gene expression. K(ATP) channels from different cell organelles are linked by some signal molecules and they can respond to common stimulation in a coordinate way. In the cardiovascular system K(ATP) has important functions. The most prominent is that opening of this channel can protect cardiac myocytes against ischemic injuries. The sarcolemmal K(ATP) may provide a basic protection against ischemia by energy sparing, while both the sarcolemmal K(ATP) and mitochondrial K(ATP) channels are necessary for the ischemia preconditioning. K(ATP) channels also have important functions including homeostasis maintenance and vascular tone regulation under physiological conditions. Further elucidation of the role of K(ATP) in the cardiovascular system will help us to regulate cell metabolism or prevent damage caused by abnormal channel functions.