Guowen Wang

A Novel Gene P28GANK Confers Multidrug Resistance by Modulating the Expression of MDR-1, Bcl-2, and Bax in Osteosarcoma Cells

As previously reported, a novel gene P28GANK conferred a multidrug resistant phenotype in gastric cancer cells. The aim of this study was to explore the role of P28GANK in the development of multidrug resistance (MDR) in osteosarcoma cells. P28GANK gene was found to be overexpressed at the mRNA level and the protein level in a cisplatin induced MDR osteosarcoma cell line Saos-2/CDDP compared to its parent cell line Saos-2. Here, we transfected the osteosarcoma cell line Saos-2 with eukaryotic expression vector of P28GANK. In vitro drug sensitivity assay suggested that Saos-2-P28GANK cells conferred resistance to both P-glycoprotein (P-gp)-related and P-gp-nonrelated drugs. Blocking P28GANK expression in MDR osteosarcoma cells Saos-2/CDDP by P28GANK-specific small interfering RNA (siRNA) increased the cell sensitivity to various chemotherapeutic drugs. Flow cytometry examination suggested that P28GANK gene expression could suppress Adriamycin-induced apoptosis accompanied by decreased accumulation and increased release of Adriamycin. Semiquantitative RT-PCR, Western blot and Luciferase reporter assay suggested that P28GANK gene could significantly up-regulate the expression of MDR-1 and Bcl-2, transcription of the MDR-1 gene and down-regulate the expression of Bax. In addition, inhibition of P28GANK expression by RNA interference or P-gp inhibition could partially reverse P28GANK-mediated MDR. Taken together, our findings suggest that down-regulation of P28GANK gene expression could sensitize osteosarcoma cells to chemotherapeutic drugs by down-regulation of the MDR-1 and Bcl-2 and up-regulation of Bax gene expression, without altering the glutathione S-transferase activity, or intracellular glutathione content in osteosarcoma cells. Further study on biological function of P28GANK may be helpful for understanding MDR mechanism of osteosarcoma and developing a strategy for osteosarcoma treatment.

Comparison of FDG PET/CT and gadolinium-enhanced mri for the detection of bone metastases in patients with cancer: A meta-analysis

Objective At present, the differences in the efficacy between PET/CT and MRI for the detection of bone metastases in patients with cancer have not been clearly delineated. We performed a meta-analysis to compare the performance of FDG PET/CT with that of gadolinium-enhanced MRI for the detection of bone metastases in patients with cancer. Methods Studies about PET/CT and MRI for the detection of bone metastases were systematically searched in the MEDLINE, EMBASE, and EBM Review databases. We calculated sensitivities, specificities, diagnostic odds ratios, positive likelihood ratios, negative likelihood ratios (NLR), and constructed summary receiver operating characteristic curves using bivariate regression models for PET/CT and MRI, respectively. Results Across 9 studies (1116 patients), FDG PET/CT has similar patient-based sensitivity (0.803 vs 0.837), specificity (0.989 vs 0.977), diagnostic odds ratio (309.0 vs 221.9), positive likelihood ratio (61.7 vs 37.0), and negative likelihood ratio (0.200 vs 0.167) with gadolinium-enhanced MRI. Areas under the curve with 95% confidence interval for FDG PET/CT and gadolinium-enhanced MRI were 0.99 (0.98–0.99) and 0.98 (0.97–0.99), respectively. Conclusions FDG PET/CT and gadolinium-enhanced MRI have excellent diagnostic performance for the detection of bone metastases in patients with cancer.

PLA2G16 Expression in Human Osteosarcoma Is Associated with Pulmonary Metastasis and Poor Prognosis.

Background Osteosarcoma is the most frequent type of malignant bone tumor in children and adolescents and is associated with a high propensity for lung metastasis. Recent experiments have indicated that PLA2G16 contributes to osteosarcoma progression and metastasis in both mouse and human osteosarcoma cell lines. The aim of this study was to compare the expression of PLA2G16 in non-metastatic and metastatic osteosarcomas to determine whether PLA2G16 expression can serve as a biomarker of osteosarcoma prognosis and metastasis. Methods Quantitative real-time PCR was used to examine PLA2G16 mRNA in primary osteosarcoma patients (18 patients without metastases and 17 patients with metastases), and immunohistochemistry (IHC) staining of PLA2G16 was performed on tissue microarrays from 119 osteosarcoma patients. Tumor metastatic behavior and survival of the patients were followed up for a minimum of 36 months and a maximum of 171 months. The prognostic value of PLA2G16 expression was evaluated by the Kaplan–Meier method and a log-rank test. Multivariate Cox regression analysis was used to identify significant independent prognostic factors. Results Osteosarcoma patients with metastasis showed a higher expression of PLA2G16 at both the mRNA and protein levels (both at P values< 0.05) than did patients without metastasis. Osteosarcoma patients with positive IHC staining of PLA2G16 expression at primary sites had shorter overall survival and metastasis-free survival (both at P values <0.02). Moreover, multivariate Cox analysis identified PLA2G16 expression as an independent prognostic factor to predict poor overall survival and metastasis-free survival (both P values < 0.03). Conclusions This study indicated that PLA2G16 expression is a significant prognostic factor in primary osteosarcoma patients for predicting the development of metastases and poor survival.

PLA2G16 promotes osteosarcoma metastasis and drug resistance via the MAPK pathway

The prognosis of metastatic osteosarcoma is dismal and a better understanding of the mechanisms underlying disease progression is essential to improve treatment options and patient outcomes. We previously demonstrated Pla2g16 overexpression in mouse osteosarcoma contributes to metastasis phenotypes and increased expression of PLA2G16 is associated with metastasis and poor prognosis in human tumors. To further examine the mechanisms through which PLA2G16 contributes to human osteosarcoma metastasis and explore the potential of PLA2G16 as a therapeutic target in osteosarcoma, we generated a panel of human osteosarcoma cell lines expressing different levels of PLA2G16. The functional analyses of these cell lines demonstrated high levels of PLA2G16 expression increased osteosarcoma cell migration, invasion, clonogenic survival, and anchorage-independent colony formation. Importantly, this activity was dependent on the phospholipase activity of PLA2G16. Additionally, PLA2G16 overexpression decreased the sensitivity of cells to a panel of chemotherapeutic agents. Analysis of downstream pathways revealed the pro-metastasis functions of PLA2G16 were mediated through the MAPK pathway, as knockdown of PLA2G16 decreased ERK1/2 phosphorylation and pharmacological inhibition of MEK significantly repressed PLA2G16 mediated cell migration and clonogenic survival. Furthermore, PLA2G16 overexpression promoted xenograft tumor growth in vivo, and these tumors exhibit increased ERK1/2 phosphorylation. Lastly, the expression of PLA2G16 is strongly correlated with the increased ERK1/2 phosphorylation in human osteosarcoma samples, and the combined lesions are associated with reduced overall and metastasis-free survival. Collectively, these results demonstrate increased PLA2G16 expression activates the MAPK pathway to enhance osteosarcoma metastasis and may be a novel therapeutic target for these cancers.

Recombined humanized endostatin (Endostar) combined with chemotherapy for advanced bone and soft tissue sarcomas in stage IV

Purpose This retrospective case-series study evaluated efficacy and safety of Endostar combined with chemotherapy in the treatment of advanced bone and soft tissue sarcomas in stage IV. Materials and Methods Forty-seven patients diagnosed with stage IV bone and soft tissue sarcomas and treated with chemotherapy in Tianjin Medical University Cancer Institute & Hospital were reviewed. Of these patients, 23 patients were treated with Endostar plus chemotherapy (designated as combined group), and 24 patients received only chemotherapy (designated as control group). Progression-free survival (PFS), overall survival (OS), objective response rate (ORR) and clinical benefit response (CBR) were analyzed to find the difference between these two groups with the purpose to investigate the role of Endostar in metastatic sarcomas. Results Endostar combined with chemotherapy had significantly increased PFS. In the combined group and control groups, the median PFS (8.6 months versus 4.4 months) and the CBR (47.8% versus 16.7%) showed significant difference (P = 0.032), while the median overall survival (11.7 months versus 10.6 months, P = 0.658) and the ORR (17.4% versus 8.3%, P = 0.167) showed no significant difference. The common grade 3-4 side effects for both groups were myelosuppression and transient elevation of transaminases. Conclusion Endostar combined with chemotherapy had significant activity to increase the PFS and improve CBR in patients with advanced sarcomas, with tolerable side effects.

ONZIN Upregulation by Mutant p53 Contributes to Osteosarcoma Metastasis Through the CXCL5-MAPK Signaling Pathway

Background/Aims: Gain-of-function of mutant p53 is associated with a high rate of lung metastasis in osteosarcoma. To investigate the mechanism of mutant p53-induced osteosarcoma metastasis, expression array analysis was performed, comparing non-metastatic osteosarcomas from p53+/- mice with metastatic osteosarcomas from p53R172H/+ mice. Onzin (Plac8) was identified as one of the genes upregulated in p53R172H/+ mouse metastatic osteosarcomas. Accordingly, we investigated the role of ONZIN in human osteosarcoma metastasis. Methods: ONZIN function and its downstream targets were examined in osteosarcoma cell lines. Assays related to tumorigenesis and metastasis, including cell migration, invasion, clonogenic survival, and soft agar colony formation, were performed in osteosarcoma cells. Additionally, mouse xenograft models were used to examine the role of ONZIN overpression in tumorigenesis in vivo. Lastly, 87 osteosarcoma patients were recruited to investigate the clinical relevance of ONZIN overexpression in metastasis and prognosis. Results: ONZIN overexpression enhanced osteosarcoma cell proliferation, clonogenic survival, migration, and invasion independent of p53 status. Furthermore, ONZIN overexpression induced CXCL5 upregulation and resulted in increased ERK phosphorylation, which contributed to more aggressive osteosarcoma metastatic phenotypes. More importantly, overexpression of ONZIN in human osteosarcoma patients was closely associated with lung metastasis, poor prognoses, and survival. Conclusions: Overexpression of ONZIN promotes osteosarcoma progression and metastasis, and can serve as a clinical biomarker for osteosarcoma metastasis and prognosis.

Comparison of the therapeutic effects of surgery combined with postoperative radiotherapy and standalone radiotherapy in treating spinal metastases of lung cancer

OBJECT There are few studies comparing the therapeutic efficacy between surgery combined with postoperative radiotherapy and standalone radiotherapy in treating spinal metastases of lung cancer. The aim of this clinical study was to compare the clinical and functional efficacy, quality of life, and survival outcomes between surgery combined with postoperative radiotherapy and standalone radiotherapy in treating spinal metastases of lung cancer. METHODS A retrospective analysis of clinical data from June 2008 to December 2013 was performed with 46 patients suffering spinal metastases of lung cancer. Among the studied patients, 25 patients received standalone radiotherapy (radiotherapy group), and the other 21 patients received surgery combined with postoperative radiotherapy (surgery group). Follow-up and survival time were analyzed. Pain levels of the patients were assessed by visual analogue scale (VAS) from pre-treatment to one month and three months after starting treatment. 3 months after surgery, Neurologic deficit of the patients was evaluated using Frankel Grade, and functional impairment were classified by Karnofsky Score. The quality of life (QOL) was assessed by EORTC QLQ-C30 questionnaire. RESULTS The follow-up period of the patients ranged from 2 to 25 months with the average of 8.8 months. In radiotherapy group, the mean survival was 8.5 months with median survival time of 7.8 months. In surgery group, the mean survival was 10.6 months with median survival of 8.4 months. The difference in survival times between the two groups was not statistically significant (P=0.24>0.05). From pre-treatment to one month and three months after treatment initiation, the VAS in both groups showed statistical significant improvement (One month: P<0.01 Three months: P=0.001, p<<0.01). In the surgery group, 85.7% of all patients had functionally useful Frankel Grade D or E after surgery, compared with 71.4% pre-operatively. The percentage was 72.0% in the radiotherapy group post-treatment, compared with 68.0% pre-treatment. The relief of Frankel Grade in surgical group was superior to that of the radiotherapy group (p=0.025, p<0.01). KPS score (80-100) percentages in surgery group and in radiotherapy group were increased by 19% and 13.3%, respectively. The improvement of KPS was more in the surgery group (p=0.013, P<0.01). In radiotherapy group, the EORTC QLQ-C30 score was 86.13 ± 12.11 before treatment and 68.39 ± 14.96 after treatment. In surgery group, the EORTC QLQ-C30 score was 84.09 ± 9.48 before treatment and 54.64 ± 15.17 after treatment. The improvement of patient QOL was more in the surgery group (p=0.004, p<0.01). CONCLUSION Compared with standalone radiotherapy, surgery combined with postoperative radiotherapy did not significantly prolong the survival time. However, surgery can improve pain, function and QOL of patients with spinal metastases of lung cancer.