Biology subjects

Koblinski, J.

Publications and source records attributed to Koblinski, J..

3 recordsLinked to original sources

bioRxiv2022

Inhibition of LATS Kinases in Ovarian Cancer Activates Cyclin D1/CDK4 and Decreases DYRK1A Activity

The controlled division of cells requires a coordination of multiple cellular pathways. Hippo pathway controls the organ size and restricts cell proliferation in response to the signals from cell surface receptors, and genetic alterations in the components of this pathway are common in cancer. LATS1 and LATS2 are homologous protein kinases that relay the signals from the environment to the Hippo effector YAP by direct phosphorylation that promotes its degradation. The genes encoding these kinases undergo frequent genetic losses in human cancers, with particularly high rates in high grade serous ovarian carcinoma (HGSOC), a highly lethal cancer with poorly understood mechanisms of pathogenesis and progression. We hypothesized that loss of LATS kinases could be a driver in this cancer and investigated signaling pathways downstream of LATS that could influence the ovarian cancer tumorigenic phenotypes. Depletion of both LATS1 and LATS2 was required to increase cell proliferation and disrupt the assembly of the cell-cycle regulatory DREAM complex. LATS-depleted human ovarian cancer cells formed bigger tumors in the immunocompromised mice, consistent with their tumor suppressor role. DREAM assembly depends on the activity of DYRK1A protein kinase, which was decreased in the LATS1/2-depleted cells. Furthermore, loss of LATS kinases increased the inhibitory phosphorylation of the retinoblastoma (Rb) family proteins, further promoting the DREAM disassembly that was rescued by CDK4 inhibitor palbociclib. Our study describes a crosstalk between the Hippo pathway and the cell cycle regulatory machinery converging on cyclin D1, a major regulator of the Rb tumor suppressor family, and highlights cellular pathways that could contribute to ovarian cancer pathogenesis and progression.

cancer biology↗

bioRxiv2022

Limitations of Busulfan to Create Humanize Mice with an Innate Immune System.

Humanized mouse models have improved biomedical research by providing a tractable system with which to perform in vivo experiments on human tissues. Use of irritators is the standard method for establishing high levels of stem cell engraftment, however not all institutes have access to this instrumentation in the animal facility. The use of busulfan has been successfully used to precondition for stem cell engraftment on a limited number of mouse backgrounds. In this report we further test the utility of busulfan as a means to successfully engraft hIL15-Tg-NSG and SGM3-NSG mouse stains which are capable of establishing the innate NK cell and myeloid immune compartments. Results from our studies show that busulfan can successfully precondition hIL15-Tg-NSG mice but not SGM3-NSG mice for high levels of human immune cell engraftment. SGM3-NSG mice preconditioned with busulfan exhibited only 10-20% human CD45 cells in the bone marrow or spleen, where as NSG and hIL15-Tg-NSG mice routinely achieved [~]80%. Busulfan preconditioned SGM3-NSG mice showed elevated levels of granulocytic MDSC, and cDC1 and cDC2 myeloid populations. This is in contrast with hIL15-TG-NSG which showed robust reconstitution of mature CD16 expressing NK cells. We conclude from our studies that busulfan is an effective means to precondition mice for CD34+ stem cell engraftment, but it may have limitations when use to precondition the SGM3-NSG model.

immunology↗

bioRxiv2022

Genomic screening reveals UBA1 as a potent and druggable target in c-MYC-high TNBC models

Triple negative breast cancer (TNBC) accounts for over 30% of all breast cancer-related deaths, despite accounting for only 10%-15% of total breast cancer cases. Targeted therapy development has largely stalled in TNBC, underlined by a lack of traditionally druggable addictions like receptor tyrosine kinases (RTKs). Here, through full genome CRISPR/Cas9 screening of TNBC models, we have uncovered the sensitivity of TNBCs to the depletion of the Ubiquitin-Like Modifier Activating Enzyme 1 (UBA1). Targeting UBA1 with the first in-class UBA1 inhibitor TAK-243 induced unresolvable ER-stress and activating transcription factor 4 (ATF4)-mediated upregulation of pro-apoptotic NOXA, leading to cell death. In five patient derived xenograft models (PDXs) of TNBC, TAK-243 therapy led to tumor inhibition or frank tumor regression. In an intracardiac metastatic model of TNBC, TAK-243 markedly reduced metastatic burden. Importantly, there was an order of magnitude greater sensitivity of TNBC lines to TAK-243 compared to normal tissue-derived cells. Lastly, c-MYC expression correlates with TAK-243 sensitivity and cooperates with TAK-243 to induce a stress response and cell death. We posit UBA1 is an important new target in TNBC expressing high levels of c-MYC. SignificanceGenomic screening of TNBC cell lines revealed broad sensitivity to depletion of the E1 ubiquitin enzyme, UBA1. Disrupting UBA1 with the first in-class inhibitor TAK-243 in TNBC models induces ER-stress through an ATF4-NOXA axis that is dependent on c-MYC, leading to apoptosis, in vitro and in vivo, primary tumor growth inhibition and metastatic inhibition.

cancer biology↗