Trastuzumab increases the sensitivity of HER2-amplified human gastric cancer cells to oxaliplatin and cisplatin by affecting the expression of telomere-associated proteins.

HER2 amplification occurs in ~20% of gastric cancer (GC) cases; however, in gastric and gastroesophageal junction cancer with HER2 gene amplification, trastuzumab in combination with cisplatin (DDP)-based chemotherapy has been reported to improve the oncological outcome. The aim of the present study was to evaluate the combined antitumor efficacy of trastuzumab and various platinum agents in GC cells and to elucidate mechanisms that may be involved in the interaction between trastuzumab and the platinum agents. The in vitro chemosensitivity of the GC cells to platinum agents was evaluated using the CellTiter 96® AQueous One Solution Cell Proliferation Assay kit. Treatment with 1.0µg/ml trastuzumab for 48 h significantly increased the sensitivity of NCI-N87 cells with HER2 amplification to oxaliplatin (Oxa) and DDP. This chemosensitivity was most prominent in the NCI-N87 cells, in which the half maximal inhibitory concentration of Oxa and DDP was decreased to ~3.29 and 6.91 times, respectively. The apoptotic effect of the platinum agents was evaluated by double-staining the GC cells with Annexin V-fluorescein isothiocyanate and propodium iodide. Consistent with the chemosensitivity analysis, apoptotic analysis indicated that trastuzumab significantly increased Oxa- and DDP-induced apoptosis in the NCI-N87 cells. Furthermore, the mRNA expression levels of various telomere-associated genes was determined by performing quantitative reverse transcription-polymerase chain reactions in a number of GC cell lines, and revealed that trastuzumab (alone and in combination with DDP) may downregulate the mRNA expression levels of the TPP1, TRF1, TRF2, TRF2IP and POT1 genes. However, western blot analysis demonstrated that trastuzumab (alone and in combination with DDP) may significantly downregulate the protein expression levels of telomeric repeat binding factor 2, protection of telomere 1 and TPP1 (formerly known as TINT1, PTOP and PIP). The results of the present study indicate a potential role of low-dose trastuzumab administration for increasing Oxa and DDP sensitivity in HER2-amplified GC cells, possibly via the downregulation of telomere-associated gene expression.

Transforming growth factor-ß1 small interfering RNA inhibits growth of human embryonic lung fibroblast HFL-I cells in vitro and defends against radiation-induced lung injury in vivo.

In the present study, a human transforming growth factor­ß1 (TGF­ß1) small interfering RNA (siRNA) plasmid vector (TGF­ß1­siRNA) was constructed to investigate its effects on the proliferation and differentiation of human lung fibroblasts in vitro and its interference effects on radiation­induced lung injury in vivo. Reverse transcription quantitative polymerase chain reaction and enzyme linked immunosorbent assay revealed that the mRNA and protein expression of TGF­ß1 in the HFL­I cells were inhibited by TGF­ß1­siRNA and flow cytometry demonstrated a significant increase in apoptosis of the HFL­I cells. Adult, female, specific­pathogen­free C57BL/6 mice were used in the in vivo animal investigations and were randomly divided into the four following groups: control without any treatment, radiation alone, radiation followed by empty vector transfection and radiation followed by TGF­ß1­siRNA vector transfection. Hematoxylin and eosin and Van­Gieson staining revealed that certain radiation­induced histopathological changes of the lung, including inflammation, edema, the density of surface pulmonary interstitial collagen fibers in the alveolar septum, TGF­ß1­positive reactions in alveolar epithelial cells and pulmonary interstitial macrophages were less marked in the mice transfected with TGF­ß1­siRNA compared with the mice without transfection or those transfected with empty vectors. The serum levels of TGF­ß1 levels in the irradiated mice increased significantly at four weeks and peaked at eight weeks after radiation, compared with the control. Serum levels of TGF­ß1 in the irradiated mice transfected with TGF­ß1­siRNA also increased gradually and a significant difference was observed compared with those irradiated without transfection. The mRNA expression levels of TGF­ß1 in the mice transfected with TGF­ß1­siRNA were markedly lower compared with those of the other radiation groups. The present study suggested that the TGF­ß1­siRNA vector reduced the activity of TGF­ß1 by downregulating the mRNA expression of TGF­ß1 and thereby effectively suppressing inflammatory reactions and defending against radiation­induced lung injury.

Promoter region methylation and loss of protein expression of PTEN and significance in cervical cancer.

The genetic basis underlying cervical tumorigenesis and progression are largely unknown. Phosphatase and tensin homologue (PTEN) is a tumor suppressor gene, and genetic changes of PTEN occurs in various types of cancer suggesting that the inactivation of PTEN may play an important role in the pathogenesis of a variety of human malignancies. In the present study, 102 cervical cancer specimens were examined for the expression of the PTEN gene and promoter methylation using methylation-specific-polymerase chain reaction and immunohistochemistry. The PTEN gene mutation was also assessed using PCR single-strand conformational polymorphism. We examined the correlation between PTEN expression and its associated methylation status and the clinical characteristics of cervical cancer. The results showed that there was one case of an A to G point mutation on exon 9 of the PTEN gene in the cervical cancer tissues. This mutation caused the change of aspartic acid to glycine, and the rate of mutation was 1%. The PTEN gene methylation rate of cervical cancer was 62% (63/102) and the rate was associated with the International Federation of Gynecology and Obstetrics stage, cell differentiation, tumor size and lymph node metastasis (P<0.05). The positive rate of PTEN expression was 49% (50/102) in cervical carcinoma and the PTEN expression between stage I-II and III-IV [60 (27/45) vs. 40% (23/57)] was statistically significant (P<0.01). The PTEN gene expression between the metastasis and no lymph node metastasis groups [26 (10/38) vs. 63% (40/64)] was significantly different (P<0.01). The PTEN gene promoter methylation and its protein expression had a significant correlation (P=0.042). These results suggest that hypermethylation can inactivate the transcription of PTEN and reduce its protein expression. Downregulated PTEN expression is involved in the pathogenesis, invasion and metastasis of cervical cancer, possibly by regulating the balance between apoptosis and proliferation. Therefore, the PTEN expression may be a good marker for the prognosis of cervical cancer.

miR-132/212 cluster inhibits the growth of lung cancer xenografts in nude mice.

OBJECTIVE: Lung cancer remains the leading cause of cancer-related death worldwide and microRNAs (miRNAs) play important roles in lung cancer progression. In this study, we investigate the effects of miR-132/212 cluster on the growth of subcutaneous xenografts of human lung cancer H1299 cells in nude mice, and further explore the underlying mechanisms. METHODS: Nude mice with subcutaneous transplantation tumor of human lung cancer H1299 cells were randomly divided into three groups: the sham group, the control vector group, and the microRNA-132/212 group. The control vector and microRNA-132/212 cluster plasmid was intratumoral injected respectively. Tumor volume was measured during the intervention process, with a tumor growth curve generated. Immunohistochemistry was performed to analyze the expression level of Ki-67, P21, CyclinD1 and CD31 in each group. RESULTS: The tumor volume of miR-132/212 group was significantly smaller than that of the control group at the terminal time point (P < 0.05). The expression levels of Ki-67, CyclinD1 and CD31 in the miR-132/212 group was significantly lower than the control group (P < 0.05), while the expression levels of P21 in the miR-132/212 group were significantly higher than the control group (P < 0.05). CONCLUSION: miR-132/212 cluster significantly inhibited the growth of subcutaneous xenografts of human lung cancer H1299 cells in nude mice. The inhibitory effect of miR-132/212 cluster in tumor growth may be mediated by upregulating the expression of P21 and downregulating the expression of CyclinD1, thereby inhibiting tumor tissue proliferation and angiogenesis and resulting in the inhibition of tumor growth.

[Expression of COX-2 and VEGF-C in papillary thyroid carcinoma and their relationship to cervical lymph metastases].

OBJECTIVE: To investigate the expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor-C (VEGF-C) in papillary thyroid carcinoma and their relationship to cervical lymph metastases. METHOD: In this study, the expressions of COX-2 and VEGF-C were examined by immunohistochemistry in papillary thyroid carcinoma tissues of 40 patients, and analysis was performed on the correlation of cervical lymph metastases with COX-2 and VEGF-C expression. RESULT: Positive expressions of COX-2 and VEGF-C were 70.0% (28/40) and 75.0% (30/40) respectively in papillary thyroid carcinoma. The positive rates of COX-2 and VEGF-C expression were 80.8% (21/26) and 84.6% (22/26) respectively in patients with cervical lymph metastases, and 50.0% (7/14) and 57.1% (8/14) respectively in patients without cervical lymph metastases, with a statistically significant difference between two groups (P<0.05, all). COX-2 was positively correlated to VEGF-C expression in papillary thyroid carcinoma (r=0.378, P<0.05). CONCLUSION: The results suggest that COX-2 and VEGF-C were highly expressed in papillary thyroid carcinoma, with possible interaction of their expressions, and may play a critical role in the cervical lymph metastases of papillary thyroid carcinoma.