No abstract

Clin Invest Med 2008; 31 (3): E160-E167. AbstractPurpose: Nanotechnology is an emerging field with significant translational potential in medicine. In this study, we applied gold nanoparticles (GNP) to enhance radiation sensitivity and growth inhibition in radiation-resistant human prostate cancer cells. Methods: Gold nanoparticles (GNPs) were synthesized using HAuCl4 as the gold particle source and NaBH4 as the reductant. Either thio-glucose or sodium citrate was then added to the solution separately to bind the GNPs to form thio-glucose-capped gold nanoparticles (Glu-GNP) and neutral gold nanoparticles (TGS-GNPs). Human prostate carcinoma DU-145 cells were exposed to vehicle, irradiation, 15nM TGS-GNPs, or 15nM Glu-GNPs, or GNPs plus irradiation. The uptake assays of GNP were performed using hemocytometer to count cells and the mass spectrometry was applied to calculate gold mass. The cytotoxicity induced by GNPs, irradiation, or GNPs plus irradiation was measured using a standard colorimetric MTT assay. Results: Exposure to Glu-GNPs resulted in a three times increase of nanoparticle uptake compared to that of TGSGNPs in each target cell (p<0.005). Cytoplasmic intracellular uptake of both TGS-GNPs and Glu-GNPs resulted in a growth inhibition by 30.57% and 45.97% respectively, comparing to 15.88% induced by irradiation alone, in prostate cancer cells after exposure to the irradiation. GluGNPs showed a greater enhancement, 1.5 to 2 fold increases within 72 hours, on irradiation cytotoxicity compared to TGS-GNPs. Tumour killing, however, did not appear to correlate linearly with nanoparticle uptake concentrations. Conclusion: These results showed that functional glucosebound gold nanoparticles enhanced radiation sensitivity and toxicity in prostate cancer cells. In vivo studies will be followed to verify our research findings.ORIGINAL RESEARCH

Zika virus is a teratogenic mosquito-transmitted flavivirus that is associated with birth defects in newborns and Guillain–Barré syndrome in adults. The virus can also be sexually transmitted, but currently, very little is known about the cell types supporting virus replication and persistence in human testes. Using primary cell cultures, we observed that Sertoli but not Leydig cells are highly susceptible to Zika virus infection, a process that is dependent on the TAM family receptor Axl. In cell culture, Sertoli cells could be productively infected with Zika virus for at least 6-weeks. Infection of Sertoli cells resulted in dramatic changes to the transcriptional profile of these cells. The most upregulated mRNA in infected cells was basic fibroblast growth factor (FGF2), a cytokine that was found to enhance Zika virus replication and support viral persistence. Together these findings provide key insights into understanding how Zika virus persists in the male reproductive tract and in turn may aid in developing antiviral therapies or strategies to minimize sexual transmission of this pathogen.

No abstract

Hypocrellins are perylenequinone pigments with substantial absorption in the red spectral region and high singlet oxygen yield. They are available in pure monomeric form and may be derivatized to optimize properties of red light absorption, tissue biodistribution and toxicity. In vitro screening of synthetic derivatives of the naturally occurring compound, hypocrellin B (HB), for optimal properties of cyto-(dark) toxicity and phototoxicity resulted in selection of three compounds for preclinical evaluation: HBEA-R1 (ethanolaminated HB), HBBA-R2 (butylaminated HB) and HBDP-R1 [2-(N,N-dimethylamino)-propylamine-HB]. Extinction coefficients at 630 nm (epsilon 630) are 6230, 6190 and 4800, respectively; and 1O2 quantum yields, phi, 0.60, 0.32 and 0.42. Intracellular uptake is essentially complete within 2 h (HBEA-R1, HBBA-R2) and 20 h (HBDP-R1). Greatest uptake is associated with lysosomes and Golgi. The HBEA-R1 and HBBA-R2 elicit phototoxicity in vitro primarily via the type II mechanism, with some type I activity under stringently hypoxic conditions. Transcutaneous phototherapy with HBEA-R1 permanently ablates EMT6/Ed tumors growing in the flanks of Balb/c mice, with minimal cutaneous effects. The HBBA-R2 does not elicit mutagenic activity in strains TA98 and TA100 of Salmonella typhimurium. Further development of selected hypocrellin derivatives as photosensitizers for photodynamic therapy is warranted.