Assessment of pulmonary toxicity of MgO nanoparticles in rats

In this study, we have evaluated the pulmonary toxicity of MgO nanoparticles (MgO NPs) in rats following their exposure. NPs in phosphate buffered saline + 1% Tween 80 were exposed via intratracheal instillation at a doses of 1 mg/kg or 5 mg/kg into rat lungs and evaluated for various tissue damage markers like alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid and histopathology of lungs at 1, 7, and 30 days of post-exposure intervals. A dose-dependant increase in ALP and LDH activity was observed in BAL fluids of rat lungs than sham control at all post-exposure periods (P <0.05), and a dose-dependant infiltration of interstitial lymphocytes, peribronchiolar lymphocytic infiltration, and dilated and/or congested vessels at 1 day post-exposure period, worsened at 1 week period, and were reduced at 1 month at histology, indicating the pulmonary toxicity of MgO NPs. In conclusion, MgO NPs exposure produced a dose-dependent pulmonary toxicity in rats and was comparable with that of Quartz particles.

Synthesis and in vitro cytotoxic activity of novel coumarinylimidazo[2,1-b]thiazole derivatives

A series of novel coumarinylimidazo[2,1-b]thiazole derivatives were synthesized by the treatment of 3-(2-aminothiazol-4-yl)-2H-chromen-2-one with phenacyl bromides followed by Vilsmeier–Haack and Knoevenagel condensation reactions. All the synthesized compounds were evaluated for their in vitro cytotoxic activity.

Mitochondrial telomerase protects cancer cells from nuclear DNA damage and apoptosis

Most cancer cells express high levels of telomerase and proliferate indefinitely. In addition to its telomere maintenance function, telomerase also has a pro-survival function resulting in an increased resistance against DNA damage and decreased apoptosis induction. However, the molecular mechanisms for this protective function remain elusive and it is unclear whether it is connected to telomere maintenance or is rather a non-telomeric function of the telomerase protein, TERT. It was shown recently that the protein subunit of telomerase can shuttle from the nucleus to the mitochondria upon oxidative stress where it protects mitochondrial function and decreases intracellular oxidative stress. Here we show that endogenous telomerase (TERT protein) shuttles from the nucleus into mitochondria upon oxidative stress in cancer cells and analyzed the nuclear exclusion patterns of endogenous telomerase after treatment with hydrogen peroxide in different cell lines. Cell populations excluded TERT from the nucleus upon oxidative stress in a heterogeneous fashion. We found a significant correlation between nuclear localization of telomerase and high DNA damage, while cells which excluded telomerase from the nucleus displayed no or very low DNA damage. We modeled nuclear and mitochondrial telomerase using organelle specific localization vectors and confirmed that mitochondrial localization of telomerase protects the nucleus from inflicted DNA damage and apoptosis while, in contrast, nuclear localization of telomerase correlated with higher amounts of DNA damage and apoptosis. It is known that nuclear DNA damage can be caused by mitochondrially generated reactive oxygen species (ROS). We demonstrate here that mitochondrial localization of telomerase specifically prevents nuclear DNA damage by decreasing levels of mitochondrial ROS. We suggest that this decrease of oxidative stress might be a possible cause for high stress resistance of cancer cells and could be especially important for cancer stem cells.

Serum human telomerase reverse transcriptase: a novel biomarker for breast cancer diagnosis

BACKGROUND

Telomerase is a ribonucleoprotein complex composed mainly of a reverse transcriptase catalytic subunit, telomerase reverse transcriptase (hTERT). Expression of hTERT confers telomerase activity, indicating that hTERT is the rate-limiting component of human telomerase. The aim of the present study was to investigate the diagnostic implications of hTERT in the serum of breast cancer patients.

METHODS

The study was conducted on 159 breast cancer patients and 41 healthy volunteers as controls. The evaluation of hTERT, cancer antigen 15.3 and carcinoembryonic antigen were performed by enzyme-linked immunosorbent assay, and analysed for their correlation with the patient's clinicopathological features.

RESULTS

27 of 52 (51.9%) patients with stage I breast cancer, 31 of 40 (77.5%) with stage II and 30 of 34 (88.2%) patients with stage III exhibited elevated hTERT levels. Serum hTERT levels showed significantly higher mean values in patients with breast cancer than healthy individuals. The sensitivity and specificity of hTERT in cancer diagnosis was 68.9 and 83.3%, respectively, which is significantly higher than conventional markers. The expression of serum hTERT was significantly correlated with telomerase activity in breast cancer tissues. Pretreatment serum hTERT levels showed a significant correlation with clinical stage, while correlation with nodal status and tumor size were marginal and no correlation was found with family history and age.

CONCLUSION

Serum hTERT is useful for diagnosing and assessing the clinical stage of breast cancer and is superior to conventional markers. Therefore, serum hTERT could have a potential application as a novel biomarker for breast cancer diagnosis.

Squamous cell carcinoma antigen and cancer antigen 125 in southern Indian cervical cancer patients

Our objective was to evaluate the diagnostic value of squamous cell carcinoma antigen (SCC-ag) and cancer antigen (CA) 125 serum tumor markers for the detection of cervical cancer. Abnormal SCC-ag(>1.5 ng/mL) and CA125 (>35 U/mL) levels were found in 64.2% and 18.9% of a series of SCC patients and in 25.0% and 42.6% of adenocarcinoma (AC) patients. The SCC-ag and CA 125 markers appeared rather specific for cervical SCCs and ACs, respectively, also correlating with clinical stage and lymph node metastasis, but not tumor size or patient age. In conclusion, SCC-ag and CA 125 are useful and reproducible markers for advanced stage disease and thus prognosis of cervical cancer.

Evaluation of tumor markers in southern Indian breast cancer patients

Tumor markers are biochemical substances elaborated by tumor cells either due to the cause or effect of malignant processes. Here we investigated serum levels of cancer antigen (CA15.3) and carcino embryonic antigen (CEA) in 153 pre and post operated southern Indian breast cancer patients (stage-I- 45, stage-II-55, stage-III- 53 samples) and 37 normal controls.Patients with malignant lesions had high frequencies of abnormal CA15.3 in stage-II (46.3%) and stage-III ( 42.6%) and of CEA in stage-III (64.3%). The mean serum levels of CA 15.3 in all stages dropped significantly after 9 days of mastectomy, but this was not the case with CEA even after 27 days. At 27 days after mastectomy, values for CA 15.3 had again significantly increased. Tumor size, node metastases (>or= 4) and stage of disease (>or= III), but not patient's age, were associated with higher preoperative levels. Evaluation of CA15.3 and CEA values showed sensitivities and specificities of 35.3% and 18.3% and 95.6% and 62.7%, respectively. Based on these findings we conclude that correlation with CA 15.3 was superior to CEA in terms of stage of disease, so that this is the more powerful marker for detecting lesions and determining response to treatment.