In vivo toxicity assessment of non-cadmium quantum dots in BALB/c mice.

Along with widespread usage of QDs in electronic and biomedical industries, the likelihood of QDs exposure to the environment and humans is deemed to occur when the QD products are degraded or handled as waste for processing. To date, there are very few toxicological reports available in the literature for non-cadmium QDs in animal models. In this work, we studied the long term in vivo toxicity of InP/ZnS QDs in BALB/c mice. The biodistribution, body weight, hematology, blood biochemistry, and organ histology were determined at a very high dosage (25 mg/kg) of InP/ZnS QDs over 84 days period. Our results manifested that the QDs formulation did not result in observable toxicity in vivo within the evaluation period, thereby suggesting that the InP/ZnS QDs can be utilized as optical probes or nanocarrier for selected in vivo biological applications when an optimized dosage is employed. FROM THE CLINICAL EDITOR: This study investigated the toxicity of quantum dots in BALB/c mice, and concluded that no organotoxicity was detectable despite of using high concentration of InP/ZnS quantum dots with prolonged exposure of 3 months.

Overexpression of human telomerase reverse transcriptase C-terminal polypeptide sensitizes HeLa cells to 5-fluorouracil­induced growth inhibition and apoptosis.

5­Fluorouracil (5­FU) is a commonly used anti­tumor chemotherapeutic drug for cervical carcinoma. However, increased drug resistance may occur following several cycles of 5­FU­based chemotherapy. Novel strategies of gene therapy for enhancing the sensitivity of cancer cells to 5­FU chemotherapy have been intensively explored. Human telomerase reverse transcriptase (hTERT)C27 is a newly constructed hTERT C­terminal polypeptide that is capable of promoting chromosome end­to­end fusion during anaphase and inducing telomere dysfunction. In the present study, the effects of hTERTC27 overexpression on 5­FU­induced proliferation inhibition and apoptosis were observed. HeLa cells were cultured and transfected with the constructed pcDNA3.1 or pcDNA3.1­hTERTC27 vectors. Expression of hTERTC27 was detected using western blot analysis and was assessed using MTT assays and flow cytometry. The results demonstrated that overexpressed hTERTC27 increased the sensitivity of the HeLa cells to 5­FU and significantly inhibited HeLa cell proliferation with 5­FU treatment. In addition, hTERTC27 overexpression evidently promoted the 5­FU­induced apoptosis by increasing the expression of activated caspase­3 and ­9 and by downregulating the expression of B­cell lymphoma 2. The results suggest that hTERTC27 overexpression is a potential clinical strategy for enhancing the antitumor effect of 5­FU chemotherapy in the treatment of cervical carcinoma.