Extraction and characterization of exosomes from the exhaled breath condensate and sputum of lung cancer patients and vulnerable tobacco consumers-potential noninvasive diagnostic biomarker source.

Noninvasive sample sources of exosomes, such as exhaled breath and sputum, which are in close proximity to the tumor microenvironment and may contain biomarkers indicative of lung cancer, are far more permissive than invasive sample sources for biomarker screening. Standardized exosome extraction and characterization approaches for low-volume noninvasive samples are critically needed. We isolated and characterized exhaled breath condensate (EBC) and sputum exosomes from healthy nonsmokers (n= 30), tobacco smokers (n= 30), and lung cancer patients (n= 40) and correlated the findings with invasive sample sources. EBC samples were collected by using commercially available R-Tubes. To collect sputum samples the participants were directed to take deep breaths, hold their breath, and cough in a collection container. Dynamic light scattering, nanoparticle tracking analysis, and transmission electron microscopy were used to evaluate the exosome morphology. Protein isolation, western blotting, exosome quantification via EXOCET, and Fourier transform infrared spectroscopy were performed for molecular characterization. Exosomes were successfully isolated from EBC and sputum samples, and their yields were adequate and sufficiently pure for subsequent downstream processing and characterization. The exosomes were confirmed based on their size, shape, and surface marker expression. Remarkably, cancer exosomes were the largest in size not only in the plasma subgroups, but also in the EBC (p < 0.05) and sputum (p= 0.0036) subgroups, according to our findings. A significant difference in exosome concentrations were observed between the control sub-groups (p < 0.05). Our research confirmed that exosomes can be extracted from noninvasive sources, such as EBC and sputum, to investigate lung cancer diagnostic biomarkers for research, clinical, and early detection in smokers.

Enhancing Proliferation of Stem Cells from Human Exfoliated Deciduous Teeth (SHED) through hTERT Expression while Preserving Stemness and Multipotency.

BACKGROUND: Stem cells from human exfoliated deciduous teeth (SHED) hold promise in regenerative medicine owing to their multipotent capabilities resembling mesenchymal stem cells (MSCs). Despite their potential, SHED have not been extensively investigated because their limited lifespan and unavailability of cell-lines pose challenges for therapeutic applications. This study investigated the effect of ectopic human telomerase reverse transcriptase (hTERT) expression on SHEDs' proliferation while preserving stemness and genomic integrity. METHODS: Deciduous teeth were collected from children aged 6-10 years. After isolation and characterization, the SHED were transduced with pBabe-puro-hTERT retrovirus to establish SHED cell-line, which was evaluated and compared with pBabe-puro (mock control) for stemness, multipotency and growth attributes through flow cytometry, trilineage differentiation, and growth kinetics. We also estimated hTERT gene expression, genomic integrity, and validated cell-line through STR analysis. RESULTS: Following hTERT transduction, SHED displayed elevated hTERT gene expression while retaining fibroblast-like morphology and mesenchymal stem cell markers. Moreover, after hTERT transduction cellular shape remained same along with increased replicative lifespan and proliferation potential. SHED-hTERT cells exhibited multi-potency and maintained stemness, as evidenced by surface marker expression and multilineage differentiation. Furthermore, genomic integrity was not affected by hTERT integration, as confirmed by STR analysis and CDKN2A gene assessment. CONCLUSION: Ectopic hTERT expression in SHED successfully prolonged their replicative lifespan and improved their ability to proliferate and migrate, while preserving their stemness, multipotency and genomic integrity, suggesting minimal carcinogenic risk. Establishment of SHED cell-line holds potential in regenerative medicine applications, especially in cell-based drugs and tissue engineering experiments.