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Breast cancer is one of the most prevalent cancers worldwide. Moreover, despite advances in antineoplastic therapies, induction of tumor cell death without off-target cytotoxicity remains a challenge. However, recent developments in localized radiotherapy and gene therapy have provided an opportunity to explore the potential for these strategies to be additive for the induction of cell death in tumor cells. Here, a novel adenoviral shuttle vector containing the proapoptotic gene Smac under the control of the ionizing radiation (IR)-induced Egr1 promoter was constructed. Following the transient transfection of the construct into MCF-7 and MDA-MB-435 breast cancer cell lines, acute and abundant expression of Smac was observed in response to IR treatment. Further analysis confirmed that the induction of Smac expression resulted in a decrease in cell viability, a slower rate of cell growth, a higher level of apoptosis and altered cell cycle progression. Using a clonogenic assay, IR-induced Smac expression was also found to significantly sensitize Smac-expressing cells to radiation-induced cell death. Taken together, these data suggest that Smac expression driven by the Egr1 promoter has the potential to serve as a radiotherapy-dependent gene therapy agent.

A total of 74 blood samples were collected from unrelated males of Han ethnic group in Chongqing of China. DNA was extracted by utilizing Chelex method (1). Each PCR reaction contained 2-10 ng DNA, 1 X Taq buffer, 1.5 mM MgCl2, 200 RM each dNTP (Pharmacia Biotech, Sweden), 1.5 U Taq polymerase (NEB, UK), 0.3 RM each primer. PCR amplifications were performed in a GeneAmp PCR System 9600 (Perkin-Elmer, Foster City, CA),with denaturing for 2 min at 94°C, followed by 30 cycles of 94°C for 50 s, 58°C for 50 s and 72°C for 30 s. PCR products were analyzed by horizontal non-denaturing polyacrylamide gel electrophoresis with discontinuous buffer system, gels were silver stained (2). Alleles were designated according to recommendation of the International Society of Forensic Genetics (3). The gene diversities, the haplotypes diversity, and the standard errors of diversity were calculated in accordance with Hou's method (4).

Mycobacterium abscessus (M. abscessus) is a non-tuberculous mycobacterium and an important emerging pathogen causing skin, soft tissue and pulmonary infections. The case of a 59-year-old man with a history of pulmonary tuberculosis (TB) and current pulmonary infection due to M. abscessus, complicated with pneumocardial disease and bronchiectasis, is described. Zhiel-Neelsen stain and acid Lowenstein-Jensen culture were both positive for acid-fast bacillus. The patient was initially misdiagnosed and ineffectively treated for pulmonary TB. Antimycobacterial susceptibility tests found the isolate to be resistant to four first-line and seven second-line antituberculosis drugs. The isolate was finally identified as M. abscessus using 16S ribosomal RNA and hsp65 and rpoB gene sequence analysis. Species of mycobacterium should be included in the differential diagnosis when patients do not respond to standard antituberculosis therapy. Molecular methods are useful for rapid and species-specific identification.