Biology subjects

Jochemsen, A. G.

Publications and source records attributed to Jochemsen, A. G..

3 recordsLinked to original sources

bioRxiv2023

Comparative phosphoproteome analysis of primary and metastatic uveal melanoma cell lines

Uveal melanoma (UM) is an ocular tumor that often develops asymptomatically. Statistically, every second patient eventually develops metastases that drastically worsen the prognosis by several months of overall survival. While isolated liver perfusion with melphalan and more recently immunotherapy (Tebentafusp) are the few treatment options available for metastatic UM patients, their application is complex or expensive. There is an urgent need to understand drug response and identify potential avenues for therapy. Hence, we focused on uncovering altered phosphorylation signaling events in metastatic UM using proteomics as an approach to identify potential drug targets. We analyzed the phosphoproteomes of the primary UM cell line Mel270 and two cell lines OMM2.3 and OMM2.5, derived from metastatic lesions of the same patient. We found 177 phosphosites to be altered significantly between primary and metastatic cell lines. Pathway analysis of up-regulated phosphosites in metastatic lines suggests that Rho signaling and mitotic cell cycle to be significantly altered uncovering potential routes of signaling for metastasis. Clinical data from LUMC and TCGA datasets uncovered MARK3 expression (which links to Rho signaling) correlation with chromosome 3 status, a prognostic marker in UM, suggesting that MARK3 kinase might be involved in metastatic UM signaling.

cancer biology↗

bioRxiv2021

Patient-derived zebrafish xenograft models reveal ferroptosis as a fatal and druggable weakness in metastatic uveal melanoma

Uveal melanoma (UM) is the most common intraocular melanoma, derived from transformed melanocytes of the uvea. Although treatment of primary UM is usually successful, there is a high risk (up to 50%) of liver metastasis with negligible long-term survival. There are currently no reproducible patient-derived animal models that faithfully recapitulate the latter stages of metastatic dissemination of UM, hindering the discovery of curative treatments. To overcome this problem and to accelerate the development of new metastatic UM treatments, we developed a patient-derived zebrafish xenograft (zf-PDX) model, using spheroid cultures generated from metastatic and primary UM tissues. Engrafted UM cells derived from these spheroid cultures give rise to metastatic lesions and recapitulate the molecular features of UMs and their potential drug sensitivity. Importantly, harnessing this versatile model, we reveal a high sensitivity of circulating UM cells to ferroptosis induction in vivo by Erastin and RSL3. Our findings are further corroborated by supportive analysis of patient data implicating ferroptosis as a new, and druggable, target for the treatment of metastatic UM patients, specifically in those with BAP1 loss in the tumor.

cancer biology↗

bioRxiv2020

Breast cancer dormancy is associated with a 4NG1 state and not senescence

Reactivation of dormant cancer cells can lead to cancer relapse, metastasis and patient death. Dormancy is a non-proliferative state and is linked to late relapse and death. No targeted therapy is currently available to eliminate dormant cells, highlighting the need for a deeper understanding and reliable models. Here, we thoroughly characterize the dormant D2.OR and proliferative D2A1 breast cancer cell line models in vivo and in vitro, and assess if there is overlap between a dormant and a senescent phenotype. We show that D2.OR but not D2A1 cells become dormant in the liver of an immunocompetent model. In vitro, we show that D2.OR cells are polyploid ER+/Her2+ cells, and in response to a 3D environment are growth arrested in G1, of which a subpopulation resides in a 4NG1 state. The dormancy state is reversible, and not associated with a senescence phenotype. This will aid future research on breast cancer dormancy.

cell biology↗