Lu Jun Zhao

Prognostic value of epidermal growth factor receptor mutations in resected lung adenocarcinomas

The purpose of this study was to evaluate the association between epidermal growth factor receptor (EGFR) mutations and prognosis in patients with completely resected lung adenocarcinoma. A total of 131 patients were included in this study. EGFR mutation status in exons 18–21 of the tyrosine kinase-binding domain was detected using nested PCR amplification of individual exon. The χ2 test was used to analyze the associations between EGFR mutations and the different variables. The log-rank test and Cox regression model were used to evaluate the factors influencing disease-free survival (DFS) and overall survival (OS). EGFR mutations in 18–21 exons were detected in 58 of the 131 patients (44.3xa0%). Smoking status (Pxa0=xa00.029), N stage (Pxa0=xa00.021), and pathologic stage (Pxa0=xa00.048) were significantly associated with EGFR mutations. The median DFS in mutant EGFR and wild-type EGFR groups was 36.6 and 25.7xa0months, respectively (Pxa0=xa00.533). No significant correlation was observed between EGFR mutations and OS (Pxa0=xa00.564). However, patients with exon 19 mutation tended to have longer DFS than those with exon 21 mutation (46.2 vs. 21.9xa0months, Pxa0=xa00.056), and the 1-, 2-, and 3-year OS rates were significantly higher in patients with exon 19 mutation compared to patients with exon 21 mutation (100, 96.7, 93.3 vs. 91.3, 82.6, 60.9xa0%, respectively, Pxa0=xa00.01). Our data demonstrated that EGFR mutations do not have significant prognostic value in primary resected lung adenocarcinomas, but patients with exon 19 mutation tended to have better prognostic value compared to patients with exon 21 mutation.

Mesenchymal stem cells generate pericytes to promote tumor recurrence via vasculogenesis after stereotactic body radiation therapy.

BACKGROUNDnStereotactic body radiation therapy (SBRT) is postulated to enhance the recruitment of mesenchymal stem cells (MSCs) into the tumor microenvironment, which promote tumor recurrence. The aim of this study is to determine the molecular mechanisms behind SBRT stimulating MSC migration and differentiation.nnnMETHODSnIn vitro, mediated factors and migrated MSCs (post-SBRT) were generated. In vivo, bone-marrow derived MSCs were identified and harvested from green fluorescent protein (GFP)-expressing transgenic male mice and transplanted into sub-lethally irradiated recipient female mice to establish a model of bone marrow transplantation. Lewis lung carcinoma and malignant melanoma-bearing recipient mice were treated with SBRT, 14u2009Gy/1 fraction. The migration and differentiation potential of MSCs were characterized.nnnRESULTSnSBRT increased the release of stromal cell derived factor-1α (SDF-1α) and platelet-derived growth factor-B (PDGF-B) by tumor cells; these ligands bound to chemokine (C-X-C motif) receptor 4 (CXCR4) and platelet-derived growth factor receptor-β (PDGFR-β), respectively, on circulating bone marrow-derived MSCs, resulting in engraftment of the MSCs into the tumor parenchyma. The newly-homed MSCs differentiated into pericytes, which induced the tumor vasculogenesis, and promoted tumor regrowth. Targeted therapies, AMD3100 and imatinib abrogated MSC homing, vasculogenesis, and tumor regrowth.nnnCONCLUSIONnBone-marrow derived MSCs migrate to the tumor parenchyma and differentiate into pericytes, inducing tumor vasculogenesis after SBRT, and promoting tumor recurrence. MSC migration and maturation may be abrogated with AMD3100 and imatinib. This novel treatment strategy warrants clinical investigation.

Targeting pyruvate kinase M2 contributes to radiosensitivity of non-small cell lung cancer cells in vitro and in vivo

Aerobic glycolysis, a metabolic hallmark of cancer, is associated with radioresistance in non-small cell lung cancer (NSCLC). Pyruvate kinase M2 isoform (PKM2), a key regulator of glycolysis, is expressed exclusively in cancers. However, the impact of PKM2 silencing on the radiosensitivity of NSCLC has not been explored. Here, we show a plasmid of shRNA-PKM2 for expressing a short hairpin RNA targeting PKM2 (pshRNA-PKM2) and demonstrate that treatment with pshRNA-PKM2 effectively inhibits PKM2 expression in NSCLC cell lines and xenografts. Silencing of PKM2 expression enhanced ionizing radiation (IR)-induced apoptosis and autophagy in vitro and in vivo, accompanied by inhibiting AKT and PDK1 phosphorylation, but enhanced ERK and GSK3β phosphorylation. These results demonstrated that knockdown of PKM2 expression enhances the radiosensitivity of NSCLC cell lines and xenografts as well as may aid in the design of new therapies for the treatment of NSCLC.

Radiosensitizing effects of gefitinib at different administration times in vitro.

The optimal administration time for applying epidermal growth factor receptor inhibitors combined with radiotherapy has been unclear. We investigated the efficacy of combining gefitinib with radiation in different treatment schedules. We demonstrated that gefitinib was administered to A549 lung cancer cells in three ways (administration before irradiation, administration upon irradiation, administration after irradiation) to establish the radiosensitizing effect. Cell‐survival rates were evaluated by colony‐forming assays. Cell apoptosis and cell‐cycle distribution were investigated using flow cytometry; meanwhile, the expression of P21, Cdc25c, Bcl‐2, Bax, Rad51 and phosphorylated DNA‐PKcs (phospho‐DNA‐PK) after 6 Gy irradiation and/or gefitinib were determined by Western blot analysis. The sensitizer enhancement ratios of the gefitinib administration before irradiation, administration upon irradiation, and administration after irradiation groups were 2.23, 1.51 and 1.30, respectively. A higher apoptosis rate and G2/M phase arrest were observed in cells at 48 h after exposure to 6 Gy irradiation when gefitinib was administrated before irradiation. Increased cell apoptosis and cell cycle arrest were further supported by the expression changes of Bcl‐2, Bax, P21, Cdc25c, Rad51 and phospho‐DNA‐PK at the same time. The best radiosensitizing effect was obtained when gefitinib was delivered before irradiation. Apoptosis might be an important way of cell killing and G2/M phase arrest might be an important mechanism of apoptosis. The expression proportion changes of P21/Cdc25c proteins may play an important role in G2/M cell cycle arrest. Moreover, the pro‐apoptotic/antiapoptotic and DNA repair factors may be important modulators taking part in the molecular events of the radiosensitizing effect of gefitinib combined with irradiation. (Cancer Sci 2009)

Pericytes: a double-edged sword in cancer therapy

Pericytes, which envelope the vascular endothelium throughout the body, are often targeted to promote vascular normalization and restore normal function of blood vessels in cancer treatment. The goals of pericyte-targeted therapy tend to promote proper vascular normalization of the tumor. Tumor vascular normalization prevents metastasis, increases tumor oxygenation (making radiation more effective in killing tumor cells), optimizes Starling forces to increase delivery of cancer cell-directed therapies (e.g., chemotherapy or targeted agents), increases the efficacy of focal therapies (e.g., surgery or radiation), and increases recognition by the host immune system. We review how approaches in pericyte-targeted therapy aim to reach a balance between pro-angiogenic and anti-angiogenic function (i.e., by targeting platelet-derived growth factor beta receptors, vascular endothelial growth factor receptors and Tie-2) for tumor vascular normalization.

Radiotherapy and chemotherapy are associated with improved outcomes over surgery and chemotherapy in the management of limited-stage small cell esophageal carcinoma

BACKGROUNDnThis retrospective study evaluates the efficacy and safety of surgery and chemotherapy (S +CT) vs. radiotherapy and CT (RT+CT) in patients with limited stage small cell esophageal cancer (LS-SCEC).nnnPATIENTS AND METHODSnPatients included in analysis (from our hospital and the literature) were treated with S+CT or RT+CT between 1989 and 2012. The primary end point was overall survival (OS); secondary end points included tumor response and toxicity. Kaplan-Meier OS curves were compared with the log-rank test. Cox regression analysis was used to determine prognosticators for OS.nnnRESULTSnA total of 127 patients were included: 14 from our hospital and 113 from the literature. Fifty-four (43%) and 73 (57%) patients received S+CT or RT+CT, respectively. The median OS of all patients was 21.0 months. OS was longer for those who received RT+CT rather than S+CT (33.0 vs. 17.5 months, p=0.02), especially those with N1 disease. Uni- and multi-variate analyses showed tumor location (upper 1/3rd of esophagus) and type of treatment (S+CT) were poor prognostic factors of OS.nnnCONCLUSIONnLS-SCEC patients treated with RT+CT had an improved OS compared to those treated with S+RT. Thus, RT+CT should be considered as a primary approach for these patients.

Stereotactic body radiation therapy using the CyberKnife(®) system for patients with liver metastases.

The aim of this study was to evaluate the efficacy and toxicity of stereotactic body radiation therapy (SBRT) in the treatment of patients with liver metastases. Between August 2006 and July 2011, patients with 1–4 liver metastases were enrolled and treated with SBRT using the CyberKnife® system at Tianjin Medical University Cancer Institute and Hospital. The metastases were from different primary tumors, with a maximum tumor diameter of less than 6 cm. The primary endpoint was local control. Secondary endpoints were overall survival, progression-free survival, distant progression-free survival, and adverse events. Fifty-seven patients with 80 lesions were treated with SBRT. The 1-year and 2-year local control rates were 94.4% and 89.7%, respectively. The difference in local control between patients who received adjuvant treatment before SBRT and those who did not reached statistical significance (P=0.049). The median overall survival for the entire cohort was 37.5 months. According to the primary tumor sites, the median overall survival was not reached. The 2-year overall survival rate was 72.2% in the favorable group (primary tumors originating from the colon, breast, or stomach, as well as sarcomas); however, in the unfavorable group (primary tumors originating from the pancreas, lung, ovary, gallbladder, uterus, hepatocellular carcinoma, as well as olfactory neuroblastoma), the median overall survival and 2-year overall survival rates were 37.5 months and 55.9%, respectively (P=0.0001). Grade 1–2 fatigue, nausea, and vomiting were the most common adverse events, and no grade 3 and higher adverse events were observed. With excellent local control in the absence of severe toxicity, SBRT provides an alternative for patients with 1–4 liver metastases who cannot undergo surgery or other treatments.

The drug-resistance to gefitinib in PTEN low expression cancer cells is reversed by irradiation in vitro

BackgroundDespite of the recent success of EGFR inhibitory agents, the primary drug-resistant becomes a major challenge for EGFR inhibitor therapies. PTEN gene is an important positive regulatory factor for response to EGFR inhibitor therapy. Low-expression of PTEN is clearly one of the important reasons why tumor cells resisted to tyrosine kinase inhibitors.MethodsTo investigate the drug-resistance reversal to gefitinb and the mechanism in PTEN low expression cells which radiated with X-rays in vitro, We demonstrated that H-157 lung cancer cells (low-expression of PTEN but phospho-EGFR overexpressed tumor cells) exposed to X-rays. The PTEN expressions and radiosensitizing effects of tyrosine kinase inhibitor before and after irradiation were observed. The cell-survival rates were evaluated by colony-forming assays. The cell apoptosis was investigated using FCM. The expressions of phospho-EGFR and PTEN were determined by Western blot analysis.ResultsThe results showed that the PTEN expressions were significantly enhanced by X-rays. Moreover, the cell growth curve and survival curve were down-regulated in the gefitinib-treated groups after irradiation. Meanwhile, the radiation-induced apoptosis of tumor cells was increased by inhibition of the EGFR through up-regulation of PTEN.ConclusionThese results suggested that PTEN gene is an important regulator on TKI inhibition, and the resistance to tyrosine kinase inhibitors might be reversed by irradiation in PTEN low expression cancer cells.

Feasibility and Efficacy of Concurrent Chemoradiotherapy in Elderly Patients with Esophageal Squamous Cell Carcinoma: a Respective Study of 116 Cases from a Single Institution

BACKGROUNDnTo evaluate the safety and efficacy of combined chemoradiotherapy or radiotherapy alone in elderly patients with esophageal carcinoma to identify the best method of treatment.nnnMATERIALS AND METHODSnOne hundred and sixteen patients with esophageal carcinoma aged 70 and older who received definitive radiotherapy or chemoradiotherapy entered the study. Overall survival (OS), disease-free survival (DFS) and treatment- related toxicities were assessed.nnnRESULTSnThe median OS of the overall population was 17.9 months. For patients treated with cCRT, sCRT and radiotherapy alone, the median OS was 22.3 months, 18.0 months and 12.4 months respectively(P=0.044). Median OS for patients treated with radiotherapy dose ≥60Gy and <60Gy was 20.2 months and 10.9 months respectively (p=0.017). By univariate analysis, Chemoradiotherapy (include cCRT and sCRT) and radiotherapy dose ≥60Gy were found to achieve higher survival rates compared with radiotherapy alone and radiotherapy dose <60Gy (P=0.015, P=0.017). By multivariate analysis, chemoradiotherapy (HR=1.645, P=0.022) and radiotherapy dose ≥60Gy (HR=1.642, P=0.025) were identified as independent prognostic factors of OS.nnnCONCLUSIONSnDefinitive concurrent chemoradiotherapy could be considered as a feasible and effective treatment in esophageal carcinoma patients aged 70 and older. Radiotherapy dose 60Gy is an effective treatment option compared with standard dose radiotherapy, while higher doses are not beneficial to improve survival.

Stereotactic body radiation therapy for patients with recurrent pancreatic adenocarcinoma at the abdominal lymph nodes or postoperative stump including pancreatic stump and other stump

Background and aim The aim of this study is to evaluate the efficacy and safety of stereotactic body radiation therapy (SBRT) using CyberKnife in the treatment of patients with recurrent pancreatic adenocarcinoma at the abdominal lymph node or stump after surgery. Patients and methods Between October 1, 2006 and May 1, 2015, patients with recurrent pancreatic adenocarcinoma at the abdominal lymph node or stump after surgery were enrolled and treated with SBRT at our hospital. The primary end point was local control rate after SBRT. Secondary end points were overall survival, time to symptom alleviation, and toxicity, assessed using the Common Terminology Criteria for Adverse Events version 4.0. Results Twenty-four patients with 24 lesions (17 abdominal lymph nodes and seven stumps) were treated with SBRT, of which five patients presented with abdominal lymph nodes and synchronous metastases in the liver and lung. The 6-, 12-, and 24-month actuarial local control rates were 95.2%, 83.8%, and 62.1%, respectively. For the entire cohort, the median overall survival from diagnosis and SBRT was 28.9 and 12.2 months, respectively. Symptom alleviation was observed in eleven of 14 patients (78.6%) within a median of 8 days (range, 1–14 days) after SBRT. Nine patients (37.5%) experienced Common Terminology Criteria for Adverse Events version 4.0 grade 1–2 acute toxicities; one patient experienced grade 3 acute toxicity due to thrombocytopenia. Conclusion SBRT is a safe and effective treatment for patients with recurrent pancreatic adenocarcinoma at the abdominal lymph node or stump after surgery. Further studies are needed before SBRT can be recommended routinely.