Beneficial bacteria are becoming ever more popular gene delivery method for hypoxia-tumor targeting in vivo. In this study we investigated the therapeutic effect of new recombinant Bifidobacterium breve strain expressing interleukin (IL)-24 gene (B. breve-IL24) on head and neck tumor xenograft in mice. Briefly, B. breve transformants were obtained through electro-transformation. Bacteria-tumor-targeting ability were analyzed in vivo over different time points (1, 3 and 7 days post-bacteria injection). Furthermore, the therapeutic effect of bacteria on tumor cells in vivo were analyzed as follows: 30 Balb/c nude mice bearing subcutaneous tumor were randomly divided in three groups (Drug group, green fluorescent protein (GFP) group and Saline group). The therapy lasted for 2 weeks and included B. breve-IL24 administration via tail vein for Drug group, B. breve-GFP for GFP group and phosphate buffered saline for Saline group. The tumor growth was monitored using standard caliper technique, while the apoptosis induction in vivo was analyzed by Real-time Positron Emission Tomography/Computed Tomography (PET/CT) imaging ([18F]-ML-10 tracer). At the end of the experiment, tumor tissues were collected and analyzed by western blotting. Briefly, our results suggested that our new recombinant bacterium has the capability of targeting tumor tissue in vivo. As for the therapeutic effect, our new strain has revealed to be a promising therapeutic approach against tumor growth in vivo. Briefly, higher tumor growth inhibition and higher tumor cell apoptosis induction were observed in Drug group compared with the GFP and Saline groups. To conclude, a new recombinant strain B. breve-IL24 offers a novel, safe and clinically acceptable therapeutic approach for tumor therapy in vivo.
BackgroundThe distal GI microbiota of hospitalized preterm neonates has been established to be unique from that of healthy full-term infants; the proximal GI, more specifically gastroesophageal colonization has not been systematically addressed. We prospectively evaluated early colonization of gastroesophageal portion of the GI tract of VLBW infants.MethodsThis study involved 12 infants admitted to a level III NICU with gestational age (GA) 27 +/− 0.5 weeks and birth weight 1105 +/− 77 grams. The gastroesophageal microbial flora was evaluated using 16S rDNA analysis of aspirates collected in a sterile manner during the first 28 days of life.ResultsBacteria were detected in 9 of the 12 neonates. Ureaplasma was the dominant species in the first week of life, however, staphylococci were the predominant bacteria overall. By the fourth week, Gram (−) bacteria increased in abundance to account for 50% of the total organisms. Firmicutes were present in the majority of the neonates and persisted throughout the 4 weeks comprising nearly half of the sequenced clones. Noticeably, only two distinct species of Staphylococcus epidermidis were found, suggesting acquisition from the environment.ConclusionsIn our neonates, the esophagus and stomach environment changed from being relatively sterile at birth to becoming colonized by a phylogenetically diverse microbiota of low individual complexity. By the fourth week, we found predominance of Firmicutes and Proteobacteria. Bacteria from both phyla (CONS and Gram (−) organisms) are strongly implicated as causes of hospital-acquired infections (HAI). Evaluation of the measures preventing colonization with potentially pathogenic and pathogenic microorganisms from the hospital environment may be warranted and may suggest novel approaches to improving quality in neonatal care.
BackgroundOptical imaging is one of the most common, low-cost imaging tools used for investigating the tumor biological behavior in vivo. This study explores the feasibility and sensitivity of a near infrared fluorescent protein mKate2 for a long-term non-invasive tumor imaging in BALB/c nude mice, by using a low-power optical imaging system.MethodsIn this study, breast cancer cell line MDA-MB-435s expressing mKate2 and MDA-MB-231 expressing a dual reporter gene firefly luciferase (fLuc)-GFP were used as cell models. Tumor cells were implanted in different animal body compartments including subcutaneous, abdominal and deep tissue area and closely monitored in real-time. A simple and low-power optical imaging system was set up to image both fluorescence and bioluminescence in live animals.ResultsThe presence of malignant tissue was further confirmed by histopathological assay. Considering its lower exposure time and no need of substrate injection, mKate2 is considered a superior choice for subcutaneous imaging compared with fLuc. On the contrary, fLuc has shown to be a better option when monitoring the tumor in a diffusive area such as abdominal cavity. Furthermore, both reporter genes have shown good stability and sensitivity for deep tissue imaging, i.e. tumor within the liver. In addition, fLuc has shown to be an excellent method for detecting tumor cells in the lung.ConclusionsThe combination of mKate2 and fLuc offers a superior choice for long-term non-invasive real-time investigation of tumor biological behavior in vivo.
In the present research, we have successfully built the MDA-MB-435s-mKate2 cell line that can be used as a suitable cell model for breast cancer therapy and anti-cancer drug evaluation by non-invasive fluorescence imaging in mice.
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