Non-invasive monitoring of Streptococcus pyogenes vaccine efficacy using biophotonic imaging.

Streptococcus pyogenes infection of the nasopharynx represents a key step in the pathogenic cycle of this organism and a major focus for vaccine development, requiring robust models to facilitate the screening of potentially protective antigens. One antigen that may be an important target for vaccination is the chemokine protease, SpyCEP, which is cell surface-associated and plays a role in pathogenesis. Biophotonic imaging (BPI) can non-invasively characterize the spatial location and abundance of bioluminescent bacteria in vivo. We have developed a bioluminescent derivative of a pharyngeal S. pyogenes strain by transformation of an emm75 clinical isolate with the luxABCDE operon. Evaluation of isogenic recombinant strains in vitro and in vivo confirmed that bioluminescence conferred a growth deficit that manifests as a fitness cost during infection. Notwithstanding this, bioluminescence expression permitted non-invasive longitudinal quantitation of S. pyogenes within the murine nasopharynx albeit with a detection limit corresponding to approximately 10(5) bacterial colony forming units (CFU) in this region. Vaccination of mice with heat killed streptococci, or with SpyCEP led to a specific IgG response in the serum. BPI demonstrated that both vaccine candidates reduced S. pyogenes bioluminescence emission over the course of nasopharyngeal infection. The work suggests the potential for BPI to be used in the non-invasive longitudinal evaluation of potential S. pyogenes vaccines

Improved in vivo antitumor effect of a daunorubicin - GnRH-III bioconjugate modified by apoptosis inducing agent butyric acid on colorectal carcinoma bearing mice

Compared to classical chemotherapy, peptide-based drug targeting is a promising therapeutic approach for cancer, which can provide increased selectivity and decreased side effects to anticancer drugs. Among various homing devices, gonadotropin-releasing hormone-III (GnRH-III) peptide represents a suitable targeting moiety, in particular in the treatment of hormone independent tumors that highly express GnRH receptors (e.g. colon carcinoma). We have previously shown that GnRH-III[(4)Lys(Ac),(8)Lys(Dau = Aoa)] bioconjugate, in which daunorubicin was attached via oxime linkage to the (8)Lys of a GnRH-III derivative, exerted significant in vivo antitumor effect on subcutaneously developed HT-29 colon tumor. In contrast, results of the study reported here indicated that this compound was not active on an orthotopically developed tumor. However, if Lys in position 4 was acylated with butyric acid instead of acetic acid, the resulting bioconjugate GnRH-III[(4)Lys(Bu),(8)Lys(Dau = Aoa)] had significant tumor growth inhibitory effect. Furthermore, it prevented tumor neovascularization, without detectable side effects. Nevertheless, the development of metastases could not be inhibited by the bioconjugate; therefore, its application in combination with a metastasis preventive agent might be necessary in order to achieve complete tumor remission. In spite of this result, the treatment with GnRH-III[(4)Lys(Bu),(8)Lys(Dau = Aoa)] bioconjugate proved to have significant benefits over the administration of free daunorubicin, which was used at the maximum tolerated dose

The gut fermentation product butyrate, a chemopreventive agent, suppresses glutathione S-transferase theta (hGSTT1) and cell growth more in human colon adenoma (LT97) than tumor (HT29) cells.

Contains fulltext : 48397.pdf (publisher's version ) (Closed access)PURPOSE: The gut fermentation product of dietary fiber, butyrate, inhibits growth of HT29, an established tumor cell line. It also induces detoxifying enzymes belonging to the glutathione S-transferase family (GSTs), namely hGSTM2, hGSTP1, hGSTA4, but not of hGSTT1 . Here we investigated kinetics of effects in HT29 and compared sensitivities with preneoplastic LT97 colon adenoma cells, to assess mechanisms of colon cancer chemoprevention in two stages of cell transformation. METHODS: We determined cell growth after butyrate treatment by quantifying DNA, GST expression by Northern/Western Blotting or biochemical analysis and butyrate consumption by measuring the residual concentrations in the cell culture supernatants. Stability of GST-theta (hGSTT1) mRNA was assessed in HT29 cells after inhibition of transcription with actinomycin D. RESULTS: LT97 adenoma cells consumed twofold more butyrate and were more sensitive to growth inhibition than HT29 (EC(50)1.9 mM and 4.0 mM, respectively). Butyrate did not induce GSTs, but instead reduced hGSTT1 in LT97 and HT29. CONCLUSIONS: Butyrate has suppressing-agent activities in human colon cells by inhibiting two survival factors, namely hGSTT1 and cell growth, with LT97 more sensitive than HT29. These findings indicate that butyrate formation in the gut lumen of humans could be protective by reducing survival of transformed colon cells