Collagen ultrastructural symmetry and its malignant alterations in human breast cancer revealed by polarization‐resolved second‐harmonic generation microscopy

Several specific alterations of the extracellular matrix can be considered a distinctive hallmark of cancer. In particular, a different morphology of the collagen scaffold is frequently found within the peritumoural environment. In this study, we report about a significant difference in the ultrastructural organization of collagen at the supra‐molecular level between the perilesional scaffold and the tumour area in human breast carcinoma samples. In particular, we demonstrated that polarization‐resolved second‐harmonic generation (P‐SHG) microscopy is able to link the altered collagen architecture at the ultrastructural level found in perilesional tissue with a different organization of collagen fibrils at the molecular level.     

Expression of non-muscle myosin isoforms in rabbit myometrium is estrogen-dependent

The putatative effects of different estrogen levels on the expression of non-muscle myosin isoforms in rabbit myometrium have been investigated using three monoclonal anti-platelet myosin heavy chain (MyHC) antibodies (NM-F6, NM-G2, and NM-A9). Western blotting analysis of proteolytic digests of human platelet actomyosin indicates that these antibodies are specific for three distinct epitopes. Comparative immunofluorescence tests on cultered human fibroblasts with polyclonal sequence-specific anti-MyHCA antibody suggest that the patterns of NM-F6, NM-.G2 and NM-A9, although similar, do not overlap with that of type-A MyHC. Distribution of NM myosin isoforms has been studied in indirect immunofluorescence assays using cryosections of tissues from rabbits at various stages of development, pregnancy, or from ovariectomized, 17#-estradiol-treated ovariectomized, and human chorionic gonadotropin-treated animals. Non-muscle myosin antigenicity is still present in the myometrium when the female becomes sexually competent. The immunoreactivity of non-muscle myosin for NM-F6 is steroid-independent, since it does not change with pregnancy or ovariectomy, but that of NM-G2 is estrogen-dependent; the latter disappears during pregnancy and in ovariectomized animals treated with estradiol, whereas it is expressed in ovariectomized rabbits. Although non-muscle myosin immunoreactivity for NM-A9 is detectable under all the experimental conditions, it can assume different patterns of intracellular distribution in vitro (punctate vs filamentous), depending on culture conditions and the presence of estrogens.