Recent Update on Bacteria as a Delivery Carrier in Cancer Therapy: From Evil to Allies.

Cancer is associated with a comprehensive burden that significantly affects patient's quality of life. Even though patients' disease condition is improving following conventional therapies, researchers are studying alternative tools that can penetrate solid tumours to deliver the therapeutics due to issues of developing resistance by the cancer cells. Treating cancer is not the only the goal in cancer therapy; it also includes protecting non-cancerous cells from the toxic effects of anti-cancer agents. Thus, various advanced techniques, such as cell-based drug delivery, bacteria-mediated therapy, and nanoparticles, are devised for site-specific delivery of drugs. One of the novel methods that can be targeted to deliver anti-cancer agents is by utilising genetically modified non-pathogenic bacterial species. This is due to the ability of bacterial species to multiply selectively or non-selectively on tumour cells, resulting in biofilms that leads to disruption of metastasis process. In preclinical studies, this technology has shown significant results in terms of efficacy, and some are currently under investigation. Therefore, researchers have conducted studies on bacteria transporting the anti-cancer drug to targeted tumours. Alternatively, bacterial ghosts and bacterial spores are utilised to deliver anti-cancer drugs. Although in vivo studies of bacteria-mediated cancer therapy have shown successful outcome, further research on bacteria, specifically their targeting mechanism, is required to establish a complete clinical approach in cancer treatment. This review has focused on the up-to-date understanding of bacteria as a therapeutic carrier in the treatment of cancer as an emerging field.

Tissue banking in Asia Pacific region: past, present and future.

Tissue banking in the Asia Pacific regions is driven by two main forces-firstly the International Atomic Energy Agency (IAEA) via Regional Co-operative Agreement projects and secondly by the Asia Pacific Association of Surgical Tissue Banking (APASTB). This overview is written in three sections: (1) History of tissue banking in individual country in the region. (2) History of APASTB. (3) History of IAEA programme in Asia Pacific region. The current status and future of the tissue banking programme in the region will be discussed.

Evaluation of Entamoeba histolytica recombinant phosphoglucomutase protein for serodiagnosis of amoebic liver abscess.

BACKGROUND: Amoebic liver abscess (ALA) is the most frequent clinical presentation of extra-intestinal amoebiasis. The diagnosis of ALA is typically based on the developing clinical symptoms, characteristic changes on radiological imaging and serology. Numerous serological tests have been introduced for the diagnosis of ALA, either detecting circulating amoebic antigens or antibodies. However those tests show some pitfalls in their efficacy and/or the preparation of the tests are costly and tedious. The commercial IHA kit that used crude antigen was reported to be useful in diagnosis of ALA, however high antibody background in endemic areas may cause problems in its interpretation. Thus, discovery of well-defined antigen(s) is urgently needed to improve the weaknesses of current serodiagnostic tests. METHODS: Crude antigen of E. histolytica was analysed by 2-DE and Western blot to identify a protein of diagnostic potential for ALA. The corresponding gene of the antigenic protein was then cloned, expressed and the purified recombinant protein was subsequently evaluated for serodiagnosis of ALA in an indirect ELISA format. RESULTS: Analysis of crude antigen showed that phosphoglucomutase (PGM) has the diagnostic potential. Recombinant PGM (rPGM) showed 79.17% (19/24) sensitivity and 86.67% (195/225) specificity in diagnosis of ALA based on the COV of mean +1SD. There was no significant difference between rPGM-ELISA and IHA diagnostic kit in the diagnosis of ALA in terms of sensitivity and specificity at p-value < 0.05. CONCLUSION: In conclusion, rPGM-ELISA is found to be useful for serodiagnosis of ALA. Future studies will determine whether rPGM-ELISA also detects antibodies produced in amoebic dysentery and asymptomatic cases.

Preparation, characterization and anti-angiogenesis activity of endostatin covalently modified by polysulfated heparin.

To improve the stability and anti-angiogenesis activity of endostatin (ES), ES was modified by polysulfated heparin (PSH). SDS-PAGE and free amino group determination were employed to study purity and modification procedure. The inhibition of ES and PSH-ES on endothelial cell proliferation, chorioallantoic membrane (CAM) angiogenesis and choroidal neovascularization (CNV) were studied. Western blotting was employed to study the effects on the expression of vascular endothelial growth factor (VEGF) and pigment epithelium derived factor (PEDF). Changes of the secondary structure were analyzed by circular dichroism (CD) spectra and heat stability was also studied. Our study indicated that the modified product had a better heat tolerance than ES and its anti-angiogenesis activity in CAM model and CNV model were better than that of ES. More obvious down-regulation of VEGF and up-regulation of PEDF effects of PSH-ES than ES in chorioid tissues were detected. The result of CD analysis suggested that little secondary structure change was detected compared with that of ES. Compared with native ES, PSH-ES is a potential anti-tumor drug with better heat stability and better anti-angiogenesis activity both in CAM and CNV models.

Entamoeba histolytica acetyl-CoA synthetase: biomarker of acute amoebic liver abscess.

OBJECTIVE: To characterize the Entamoeba histolytica (E. histolytica) antigen(s) recognized by moribound amoebic liver abscess hamsters. METHODS: Crude soluble antigen of E. histolytica was probed with sera of moribund hamsters in 1D- and 2D-Western blot analyses. The antigenic protein was then sent for tandem mass spectrometry analysis. The corresponding gene was cloned and expressed in Escherichia coli BL21-AI to produce the recombinant E. histolytica ADP-forming acetyl-CoA synthetase (EhACS) protein. A customised ELISA was developed to evaluate the sensitivity and specificity of the recombinant protein. RESULTS: A ∼75 kDa protein band with a pI value of 5.91-6.5 was found to be antigenic; and not detected by sera of hamsters in the control group. Tandem mass spectrometry analysis revealed the protein to be the 77 kDa E. histolytica ADP-forming acetyl-CoA synthetase (EhACS). The customised ELISA results revealed 100% sensitivity and 100% specificity when tested against infected (n=31) and control group hamsters (n=5) serum samples, respectively. CONCLUSIONS: This finding suggested the significant role of EhACS as a biomarker for moribund hamsters with acute amoebic liver abscess (ALA) infection. It is deemed pertinent that future studies explore the potential roles of EhACS in better understanding the pathogenesis of ALA; and in the development of vaccine and diagnostic tests to control ALA in human populations.

Detection of Entamoeba histolytica in experimentally induced amoebic liver abscess: comparison of three staining methods.

OBJECTIVE: To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster. METHODS: Amoebic liver abscess was experimentally induced in a hamster by injecting 1 × 10(6) of axenically cultured virulent E. histolytica trophozoites (HM1-IMSS strain) into the portal vein. After a week post-inoculation, the hamster was sacrificed and the liver tissue sections were stained with H&E, PAS and IHC stains to detect the amoebic trophozoite. RESULTS: The three stains revealed tissue necrosis and amoebic trophozoites, but with varying clarity. H&E and PAS stained the trophozoites pink and magenta, respectively, however it was difficult to differentiate the stained trophozoites from the macrophages because of their similarity in size and morphology. On the other hand, IHC stain revealed distinct brown appearance of the trophozoites in the infected liver tissues. CONCLUSIONS: It can be concluded that out of the three stains, IHC is the best for identification of E. histolytica trophozoites in tissue sections.