Physical cues from cellular external environment, especially substrate stiffness, have gradually been recognized as key factors that could mediate some cell behaviors and its physiological processes. In this study, atomic force microscopy was used to investigate the influence of substrate stiffness on cellular mechanical properties, which were regarded as potential indicators for early detection of tumor. Our results showed that the viscoelasticity of breast cancer cells was significantly lower than that of breast epithelial cells in the hard substrate, while the viscoelasticity of ovarian cancer cells did not change with substrate change. It can be seen that substrate stiffness indeed plays an important role in the development of tumor, which could be attribute to its regulation of the cellular mechanical properties.
DNA fragments in circulation released from apoptotic and necrotic cells were regarded as a novel prognostic or predictive biomarker for clinical diagnosis in recent years. However, DNA concentration in plasma ranged between 1 and 10 ng ml-1, which needed a single-molecule technology to analyze the base pair and concentration of DNA fragments. In this study, a series of different lengths of DNA fragments were studied, which showed that a good linear relationship between the DNA concentration and the molar concentration. The results suggested fluorescence correlation spectroscopy could access the nanomolar concentration of DNA labelled by SYBR Green I. Moreover, the relationship between the length of DNA fragment and the diffusion coefficient of DNA was scaled with the standard samples. The results demonstrates fluorescence correlation spectroscopy is a highly sensitive method for DNA detection.
Tumor progression and metastasis are often accompanied by the changes in the biomechanical properties of tumor tissues. In this study, the relationship between the pathological classification of different prostate tumor tissues and their biomechanical properties was investigated by atomic force microscopy. The results showed that higher pathological grade of prostate tumor tissues had lower elasticity and viscosity. Compared with traditional pathological analysis, the biomechanical characteristics of tumor tissues obtained by atomic force microscopy could offer a new index for fast clinic diagnosis and differentiation of tumor tissue. It can be used to assist in the assessment of Gleason scores of the gold standard for prostate cancer grading for radical prostatectomy.
The phosphatase and tensin homolog on chromosome 10 (PTEN) is one of important tumor suppressor proteins in ovarian cancer via negatively regulating the phosphatidylinositol 3-kinase–AKT signaling pathway and controlling genomic stability. Recent studies showed the physiological function of PTEN was closely related with its subcellular compartments. But only a few technologies could quantitatively measure the concentration of PTEN at different subcellular compartments in living cells. In this study, we used fluorescence correlation spectroscopy to measure the concentrations and dynamics of EGFP-PTEN in ovarian cancer cells HO-8910. Our results showed the increasing concentration of PTEN in the cytoplasm had an opposite trends with the nucleus after the oxidative stress stimulation which was induced by H2O2. Furthermore, the altered diffusion of PTEN at different subcellular compartments also illustrated the PTEN was trafficked from the cytoplasm to nucleus.