Tumor exosomes: a double-edged sword in cancer therapy.

Tumor cells produce and secrete more nucleic acids, proteins and lipids than normal cells. These molecules are transported in the blood or around the cells in membrane-encapsulated exosomes. Tumor-derived or tumor-associated exosomes (usually 30-100 nm in diameter) contain abundant biological contents resembling those of the parent cells along with signaling messengers for intercellular communication involved in the pathogenesis, development, progression, and metastasis of cancer. As these exosomes can be detected and isolated from various body fluids, they have become attractive new biomarkers for the diagnosis and prognosis of cancer. Furthermore, tumor exosomes have also attracted increasing attention due to their potential as novel therapeutic strategies for the treatment of cancers. On the one hand, the lipid bilayer membrane-encapsulated vesicles are promising carriers of drugs and other therapeutic materials targeting specific cancer cells. On the other hand, tumor exosomes are important mediators for modulation of the microenvironment that orchestrates events critical to the growth and metastasis of cancer cells as well as chemoresistance. Here, we summarize the advances in our understanding of tumor-associated or tumor-derived exosomes in recent years, and discuss their roles in cancer development, progression, invasion, and metastasis of cancers and, more importantly, their potential in strategies for precision therapy of various cancers as well as important caveats.

Relationship between TLR4 and NF-κB p65 protein expressions and clinical radiosensitivity of patients with esophageal squamous cell carcinoma.

OBJECTIVE: To study the relationship between TLR4 and NF-κB p65 protein expressions in tumor tissues after radiotherapy and clinical radiosensitivity of patients with esophageal squamous cell carcinoma. METHODS: A total of 93 patients with esophageal squamous cell carcinoma first treated in our hospital by radiotherapy and surgeries from November 2010 to December 2013 were selected. They were then divided into a severe reaction group, a moderate reaction group and a mild reaction group according to the postoperative pathological examination results of tumor tissues. The expressions of TLR4 and NF-κB p65 in the tumor samples were detected by Western blotting. RESULTS: Compared with the severe reaction group, the expression levels of TLR4 and NF-κB p65 in the moderate reaction group significantly increased (P<0.05). Similarly, the expression levels of the mild reaction group were significantly higher than those of the moderate reaction group (P<0.05). CONCLUSION: Reducing the expression levels of TLR4 and NF-κB p65 proteins may increase the radiosensitivity of patients with esophageal cancer.

KIF22 promotes progress of esophageal squamous cell carcinoma cells and is negatively regulated by miR-122.

Esophageal squamous cell carcinoma (ESCC) increases at fast rate of all cancer types in China, which urges the investigations of its potential mechanism. In this research, a highly expressed kinesin superfamily protein 22 (KIF22) was founded both in ESCC tissues and cancer cell lines. The following experiments pointed out that down-regulation of KIF22 remarkably restrained the malignant progression of ESCC cells. Besides, KIF22 knockdown promoted ESCC cells apoptosis and arrested cells in G0/G1 phase, while KIF22 also regulated the expression of cell cycle- and EMT-related proteins. Previous research revealed that the aberrant expressions of microRNAs (miRNAs) are related to tumors development. Based on the predict result, KIF22 was considered as the target of miR-122, which was demonstrated by luciferase reporter assay. miR-122 inhibitor could significantly reverse the function of KIF22 knockdown, including cell proliferation, migration and invasion. Furthermore, down-expressed miR-122 altered the function of KIF22 knockdown on cell cycle- and EMT-related proteins. In a word, this work illustrated the regulatory function of KIF22/miR-122 axis in ESSC and provided potential targets for potential targets for ESSC treatment.

Improved sensitization effect of sunitinib in cancer cells of the esophagus under hypoxic microenviroment.

Radiotherapy is widely used in esophageal squamous cell carcinoma (ESCC) treatment. Promoting the radiation sensitivity of cancer cells is required. Recent studies have shown that sunitinib can inhibit the growth of several cancer lines. However, few studies on the radiosensitive effect of sunitinib on ESCC cells under hypoxic conditions have been conducted. In the present study, the radiosensitive effects of sunitinib on human ESCC cells were assessed, and the underlying mechanisms were explored. ESCC cells were exposed to hypoxia and treated with sunitinib at different concentrations prior to irradiation. Sunitinib potently inhibited ESCC cell proliferation in an MTT assay. In a clonogenic survival assay, sunitinib sensitized hypoxic ESCC cells to radiation, with sensitizing enhancement ratios of 1.31-1.59. In addition, sunitinib promoted the apoptosis of ESCC cells, but did not alter their cell cycle distribution. Radiosensitization was accompanied by inhibition of the radiation-induced upregulation of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) expression. Thus, sunitinib confers radiosensitivity to esophageal cancer cells, which is associated with the downregulation of HIF-1α and VEGF expression. Sunitinib can be a promising radiosensitizer for esophageal cancer radiotherapy.

Management of primary gastric small cell carcinoma in China.

BACKGROUND: Primary gastric small cell carcinomas (GSCCs) are increasingly identified by endoscopy, and account for 15-20% of all gastric neuroendocrine tumors (NETs). GSCCs have the worst prognosis with the highest rate of metastases. PURPOSE: To provide useful information for clinicians and researchers to better manage patients with GSCC, we studied the clinical features of GSCC and explored the corresponding therapies and prognosis. METHODS: A literature search was conducted through PUBMED, EMBASE, CNKI and WanFang Databases using search terms "stomach" or "gastric" and "small cell carcinoma" or "poorly differentiated neuroendocrine carcinoma", for the period 1999 to 2012. And the cases reported were all from China. Relevant articles were identified through manual review. The reference lists of these articles were reviewed to include further appropriate articles. RESULTS: Two hundred and five eligible cases were analyzed. The median age of patients was 62 years, with a male-to-female ratio of 5.4:1. Of the tumors, 53.17% were located in the upper stomach, 25.37% in the mid, 18.54% in the distal stomach, the remaining 2.93% were found in the total stomach. The mean size was 68mm in maximum diameter, with a range of 15-150 mm. Of the one hundred and thirty-five patients, fifty appeared to be pure GSCCs, eighty-five were mixed. The median overall survival time of 195 patients was 18.50 months. The 1-, 2-, and 5-year average survival rates of 142 patients were 66.75%, 37.13%, and 20.15%, respectively. CONCLUSIONS: GSCC is a rare tumor and it is notoriously aggressive with a strong propensity for both regional and distant spread. Therapies including surgical resection, chemotherapy, and local radiotherapy, by itself or in combination with other treatment, have been used to treat GSCCs in China. To identify the most effective treatment modalities for GSCCs, we still need prospective, multicenter, randomized clinical researches.

Management of small cell carcinoma of esophagus in China.

PURPOSE: Small cell carcinoma of esophagus (SCEC) is characterized by high malignancy and early metastasis. Although the morbidity of SCEC is very low, few studies of patients with SCEC have been conducted in China, there are no sufficient studies of SCEC conducted and reported in the existing published works, and the choices of treatment remain controversial. In this work, we aim to study the clinical characteristics of SCEC, and explore the corresponding treatment and prognosis through retrospective analysis. MATERIAL AND METHODS: The original articles were identified through the leading digital libraries in China in which the terms "esophagus or esophageal" and "small cell esophageal carcinoma" appeared from 2005 to 2009, 1,176 eligible cases were reviewed for clinical data. Analysis of survival was conducted using the Kaplan-Meier method, and differences were compared using the log-rank test. RESULTS: One thousand one hundred seventy-six eligible cases were analyzed; the median age of patients was 57 years, with a male-to-female ratio of 2.4:1. The number of SCEC accounted for 1.26 % of esophageal cancer treated in the same period. Of the tumors, 89.7 % were located in mid- and lower thoracic esophagus. The average tumor length was 5.4 cm (0.5-17 cm). The median overall survival was 11.1 months for all patients. The 1-, 2-, 3-, and 5-year average overall survival rates of 469 patients was 51.1, 25.5, 13.2, 7.9 %, respectively. The median survival time for LD patients who received systemic treatment was 16.8 m, whereas for those who received local treatment (surgery), the median survival time was 10.1 m; the median survival time for ED patients who received systemic treatment was 7.4 m, compared with 5.8 m for those who received sole treatment (chemotherapy or radiotherapy). CONCLUSIONS: SCEC is a tumor characterized by high malignancy and early metastasis. Although our retrospective analysis cannot provide definitive conclusions on the optimal treatment modality for SCEC, however, our results suggest that systemic treatment combined with surgical resection plays a major role in the therapy of SCEC, systemic therapy may be an effective approach for the treatment of SCEC, and randomized, prospective, multicenter studies are needed to identify optimal treatment modalities for SCEC.