Degradation of dibutyl phthalate (DBP) by a bacterial consortium and characterization of two novel esterases capable of hydrolyzing PAEs sequentially.

Phthalate esters (PAEs), a class of toxic anthropogenic compounds, have been predominantly used as additives or plasticizers, and great concern and interests have been raised regarding its environmental behavior and degradation mechanism. In the present study, a bacterial consortium consisting of Microbacterium sp. PAE-1 and Pandoraea sp. PAE-2 was isolated by the enrichment method, which could degrade dibutyl phthalate (DBP) completely by biochemical cooperation. DBP was converted to phthalic acid (PA) via monobutyl phthalate (MBP) by two sequential hydrolysis steps in strain PAE-1, and then PA was further degraded by strain PAE-2. Strain PAE-1 could hydrolyze many dialkyl Phthalate esters (PAEs) including dimethyl, diethyl, dibutyl, dipentyl, benzyl butyl, dihexyl, di-(2-ethyhexyl) and their corresponding monoalkyl PAEs. Two esterase genes named dpeH and mpeH, located in the same transcription unit, were cloned from strain PAE-1 by the shotgun method and heterologously expressed in Escherichia. coli (DE3). The Km and kcat values of DpeH for DBP were 9.60 ± 0.97 µM and (2.72 ± 0.06) × 106 s-1, while those of MpeH for MBP were 18.61 ± 2.00 µM and (5.83 ± 1.00) × 105 s-1, respectively. DpeH could only hydrolyze dialkyl PAEs to the corresponding monoalkyl PAEs, which were then hydrolyzed to PA by MpeH. DpeH shares the highest similarity (53%) with an alpha/beta hydrolase from Microbacterium sp. MED-G48 and MpeH shows only 25% identity with a secreted lipase from Trichophyton benhamiae CBS 112371, indicating that DpeH and MpeH are two novel hydrolases against PAEs.

Terrimonas soli sp. nov., isolated from farmland soil.

A Gram-staining-negative, aerobic, non-motile and rod-shaped bacterium that produced yellow viscous colonies, designated FL-8T, was isolated from farmland soil in Chuzhou, Anhui province, PR China. 16S rRNA gene sequence similarities between strain FL-8T and the type strains of species of the genus Terrimonas with validly published names ranged from 94.6 to 96.1 %. Strain FL-8T contained iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH as the predominant fatty acids. The predominant polar lipid of strain FL-8T was phosphatidylethanolamine. The sole respiratory quinone of strain FL-8T was MK-7 and the DNA G+C content was 44.8 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain FL-8T is considered to represent a novel species of the genus Terrimonas, for which the name Terrimonassoli sp. nov. is proposed. The type strain is FL-8T (=CCTCC AB 2017059T=JCM 32095T).

Low-dose docetaxel enhances the anti-tumour efficacy of a human umbilical vein endothelial cell vaccine.

Our previous studies have indicated that human umbilical vein endothelial cell (HUVEC) vaccination appears to be a potentially promising anti-angiogenesis therapy, but the modest therapeutic anti-tumour efficiency limits its clinical use. This highlights the importance of identifying more potent therapeutic HUVEC vaccine strategies for clinical testing. In the present study, the immune-modulating doses of docetaxel (DOC) was combined with 1 × 106 viable HUVECs as a means to enhance the therapeutic anti-tumour efficiency of the HUVEC vaccine. Our results demonstrated that 5 mg/kg DOC administrated prior to HUVEC vaccine could most effectively assist HUVEC vaccine to display a remarkable suppression of tumour growth and metastasis as wells as a prolongation of survival time in a therapeutic procedure. CD31 immunohistochemical analysis of the excised tumours confirmed a significant reduction in vessel density after treatment with the HUVEC vaccine with 5 mg/kg DOC. Additionally, an increased HUVEC-specific antibody level, activated CTLs and an elevated IFN-γ level in cultured splenocytes were revealed after treatment with HUVEC vaccine with 5 mg/kg DOC. Finally, 5 mg/kg DOC coupled with the HUVEC vaccine led to induction of significant increases in CD8+T cells and decrease in Tregs in the tumour microenvironment. Taken together, all the results verified that 5 mg/kg DOC could assist HUVEC vaccine to elicit strong HUVEC specific humoral and cellular responses, which could facilitate the HUVEC vaccine-mediated inhibition of cancer growth and metastasis. These findings provide the immunological rationale for the combined use of immune-modulating doses of DOC and HUVEC vaccines in patients with cancer.

Combination of Human Umbilical Vein Endothelial Cell Vaccine and Docetaxel Generates Synergistic Anti-Breast Cancer Effects.

Background: A human umbilical vein endothelial cell (HUVEC) vaccine is a promising anti-angiogenesis therapy, but the modest therapeutic antitumor efficacy restricts its clinical use. Preclinical evidence supports the combination of antiangiogenic agents and chemotherapy for cancer treatment. Materials and Methods: In the present study, docetaxel (DOC) was combined with HUVEC vaccine to develop a HUVEC-DOC treatment regime. This study was designed to investigate the synergistic anti-breast cancer effects and mechanisms of the HUVEC-DOC treatment. Results: Compared with either agent monotherapy, HUVEC-DOC treatment exhibited more favorable anti-EMT-6 breast cancer effects in vivo. CD31 immunohistochemical analysis of the excised tumors showed notable decreases in vessel density after HUVEC-DOC administration, while T cells isolated from mice immunized with HUVEC-DOC showed increased cytotoxicity against HUVECs. Furthermore, the quantity of interferon gamma released from HUVEC-DOC-administered mice was significantly higher than the other three groups, and enhanced CD8+ T cell infiltration was observed more frequently in tumors excised from HUVEC-DOC-treated mice. Finally, the percentage of regulatory T cells was significantly decreased after HUVEC-DOC immunization. Conclusions: All the data verified that combining DOC with a HUVEC vaccine could generate synergistic anti-breast cancer activity, which might have the potential for combination treatment of human breast cancer.

Assessment of in vivo anti-tumor activity of human umbilical vein endothelial cell vaccines prepared by various antigen forms.

Human umbilical vein endothelial cell (HUVEC) vaccine has been proved as an effective whole-cell vaccine, but the modest therapeutic anti-tumor efficiency limits its clinical use. Various antigen forms, including paraformaldehyde-fixed HUVEC, glutaraldehyde-fixed HUVEC, HUVEC lysate and live HUVEC, have been intensively used in HUVEC vaccine preparation, however, the most effective antigen form has not yet been identified. In the present study, these four commonly used antigen forms were used to prepare vaccines named Para-Fixed-EC, Glu-Fixed-EC, Lysate-EC, and Live-EC respectively, and the anti-tumor efficacy of these four vaccines was investigated. Results showed that Live-EC exhibited the most favorable anti-tumor growth and metastasis effects among the four vaccines in both H22 hepatocellular carcinoma and Lewis lung cancer models. High titer anti-HUVEC antibodies were detected in Live-EC immunized mice sera, and the immune sera of Live-EC group could significantly inhibit HUVEC proliferation and tube formation. Moreover, T cells isolated from Live-EC immunized mice exhibited strong cytotoxicity against HUVEC cells, with an increasing IFN-γ and decreasing Treg production in Live-EC immunized mice. Finally, CD31 immunohistochemical analysis of the excised tumors verified a significant reduction in vessel density after Live-EC vaccination, which was in accordance with the anti-tumor efficiency. Taken together, all the results proved that live HUVEC was the most effective antigen form to induce robust HUVEC specific antibody and CTL responses, which could lead to the significant inhibition of tumor growth and metastasis. We hope the present findings would provide a rationale for the further optimization of HUVEC vaccine.

In vivo antitumor activity evaluation of cancer vaccines prepared by various antigen forms in a murine hepatocellular carcinoma model.

Cancer cell vaccines with strong specificity and low tolerance have been revealed to be a promising option for oncology treatment. Various antigen forms, including tumor cell lysate and glutaraldehyde-fixed tumor cells, have been intensively used in cancer vaccine preparation. However, the most effective antigen form has not yet been identified. In the present study, the antitumor efficiency of vaccines prepared by these two antigen forms was systematically investigated. Murine H22 hepatocellular carcinoma cell lysate and glutaraldehyde-fixed H22 hepatocellular carcinoma cells were conjugated with Freund's adjuvant to prepare vaccines, H22-TCL and Fixed-H22-CELL, respectively. H22-TCL and Fixed-H22-CELL were administrated by subcutaneous immunization in prophylactic and therapeutic strategies. The results of the present study revealed that H22-TCL immunization induced more significant inhibition on tumor growth and metastasis compared with Fixed-H22-CELL injection. Furthermore, histopathological observation demonstrated that H22-TCL vaccine induced larger areas of continuous necrosis within tumors compared to the Fixed-H22-CELL vaccine, which was associated with the extent of tumor inhibition. More importantly, the H22-TCL vaccine injection elicited more evident antigen-specific antibody responses compared with the Fixed-H22-CELL injection. Splenocytes from H22-TCL vaccinated mice also exhibited a more significant T lymphocytes proliferation compared with that from Fixed-H22-CELL-treated mice. All the results indicated that whole tumor cell lysate may be a more effective antigen form in cancer vaccine preparation compared with glutaraldehyde-fixed tumor cells, which elicited more marked antigen specific humoral and cellular immune responses resulted with a superior antitumor efficiency. This would have important clinical signification for cancer vaccine preparation and serve a role in prompting this to other researchers.