Biology subjects

Krndija, D.

Publications and source records attributed to Krndija, D..

2 recordsLinked to original sources

bioRxiv2019

A new analytical pipeline for the study of the onset of mammary gland oncogenesis based on mammary organoid transplantation and organ clearing

Metastasis formation is a multi-step process starting from the dissemination of transformed carcinomatous cells from the primary tumor and could occur at a very early stage of oncogenesis, before primary tumor detection. The adult mammary gland provides a unique model to investigate epithelial cell dissemination processes. Tissue clearing techniques allow imaging samples of large volume. uDSICO clearing, one of the latest tissue clearing technique developed, provides optical imaging of whole organ due to organ clearing and tissue size reduction. We wanted to take advantage of this technique to study rare events occurring in vivo. Here, we have established a new analytical pipeline exploiting the regenerative properties of the mammary epithelium following orthotropic transplantation of organoids together with the uDISCO organ size reduction and clearing method to study early cell dissemination in the mammary gland. As proof of concept, we analyzed the localization of epithelial cells overexpressing the oncogenic protein atypical protein kinase C iota (aPKCi+) in the normal mammary gland and we were able to visualize epithelial aPKCi+ cells, surrounded by normal epithelial cells, escaping from the normal mammary epithelium and disseminating into the surrounding stroma.

cell biology↗

bioRxiv2019

IGF1R undergoes active and directed centripetal transport on filopodia upon receptor activation

Filopodia are thin, actin-based membrane protrusions with roles in sensing external mechanical and chemical cues, such as growth factor gradients in tissues. It was proposed that the chemical sensing role of filopodia is achieved through clearance of activated signaling receptors from filopodia. Type I insulin-like growth factor receptor (IGF1R) is a key regulator of normal development and growth, as well as tumor development and progression. Its biological roles depend on its activation upon IGF1 binding at the cell membrane. IGF1R behavior at the cell membrane and in particular in filopodia, has not been established. We found that IGF1 activation led to a gradual reduction in IGF1R puncta in filopodia, and that this clearance depended on actin, non-muscle myosin II, and IGF1R kinase activity. Using single particle tracking of filopodial IGF1R, we established that ligand-free IGF1R undergoes non-directional unidimensional diffusion along the filopodium. Moreover, after initial diffusion, the ligand-bound IGF1R is actively transported along the filopodium towards the filopodium base, and consequently cleared from the filopodium. Our results show that IGF1R can move directionally on the plasma membrane protrusions, supporting a sensory role for filopodia in interpreting local IGF1 gradients.

cell biology↗