Publications by authors named "Joanna Kovalski"

Oncogenic protein dosage is tightly regulated to enable cancer formation but how this is regulated by translational control remains unknown. The Myc oncogene is a paradigm of an exquisitely regulated oncogene and a driver of pancreatic ductal adenocarcinoma (PDAC). Here we use a CRISPR interference screen in PDAC cells to identify activators of selective MYC translation.

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Article Synopsis
  • The study investigates how cancer cells, particularly pancreatic ductal adenocarcinoma (PDAC), regulate oncogenic protein levels to survive, focusing on the Myc oncogene.
  • Using CRISPRi screens, four RNA binding proteins (RBPs) were identified as key activators of selective translation, with RBM42 being the most critical and linked to poor patient survival.
  • RBM42 was found to be a ribosome-associated protein that binds to the 5' untranslated region (5'UTR) of specific oncogenic transcripts, promoting their translation and supporting cancer growth, offering potential for new therapeutic strategies.
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Drug combinations are key to circumvent resistance mechanisms compromising response to single anti-cancer targeted therapies. The implementation of combinatorial approaches involving MEK1/2 or KRASG12C inhibitors in the context of KRAS-mutated lung cancers focuses fundamentally on targeting KRAS proximal activators or effectors. However, the antitumor effect is highly determined by compensatory mechanisms arising in defined cell types or tumor subgroups.

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Translational control of mRNAs is a point of convergence for many oncogenic signals through which cancer cells tune protein expression in tumorigenesis. Cancer cells rely on translational control to appropriately adapt to limited resources while maintaining cell growth and survival, which creates a selective therapeutic window compared to non-transformed cells. In this review, we first discuss how cancer cells modulate the translational machinery to rapidly and selectively synthesize proteins in response to internal oncogenic demands and external factors in the tumor microenvironment.

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A central component of Myc's role as a master coordinator of energy metabolism and biomass accumulation is its ability to increase the rate of protein synthesis, driving cell cycle progression, and proliferation. Importantly, Myc-induced alterations in both global and specific mRNA translation is a key determinant of Myc's oncogenic function. Herein, we provide five assays to enable researchers to measure global protein synthesis changes, to identify the translatome uniquely regulated by Myc and to investigate the mechanisms generating the tailored Myc translation network.

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KRAS receives and relays signals at the plasma membrane (PM) where it transmits extracellular growth factor signals to downstream effectors. SNORD50A/B were recently found to bind KRAS and inhibit its tumorigenic action by unknown mechanisms. KRAS proximity protein labeling was therefore undertaken in SNORD50A/B wild-type and knockout cells, revealing that SNORD50A/B RNAs shape the composition of proteins proximal to KRAS, notably by inhibiting KRAS proximity to the SNARE vesicular transport proteins SNAP23, SNAP29, and VAMP3.

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Although oncogenic mutations in the three major Ras isoforms, , and , are present in nearly a third of human cancers, therapeutic targeting of Ras remains a challenge due to its structure and complex regulation. However, an in-depth examination of the protein interactome of oncogenic Ras may provide new insights into key regulators, effectors and other mediators of its tumorigenic functions. Previous proteomic analyses have been limited by experimental tools that fail to capture the dynamic, transient nature of Ras cellular interactions.

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Proximity-dependent biotin labeling (BioID) may identify new targets for cancers driven by difficult-to-drug oncogenes such as Ras. Therefore, BioID was used with wild-type (WT) and oncogenic mutant (MT) H-, K-, and N-Ras, identifying known interactors, including Raf and PI3K, as well as a common set of 130 novel proteins proximal to all Ras isoforms. A CRISPR screen of these proteins for Ras dependence identified mTOR, which was also found proximal to MT Ras in human tumors.

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RNA-protein interactions play numerous roles in cellular function and disease. Here we describe RNA-protein interaction detection (RaPID), which uses proximity-dependent protein labeling, based on the BirA* biotin ligase, to rapidly identify the proteins that bind RNA sequences of interest in living cells. RaPID displays utility in multiple applications, including in evaluating protein binding to mutant RNA motifs in human genetic disorders, in uncovering potential post-transcriptional networks in breast cancer, and in discovering essential host proteins that interact with Zika virus RNA.

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Staphylococcus aureus is both a major bacterial pathogen as well as a common member of the human skin microbiota. Due to its widespread prevalence as an asymptomatic skin colonizer and its importance as a source of skin and soft tissue infections, an improved understanding of how S. aureus attaches to, grows within, and breaches the stratified layers of the epidermis is of critical importance.

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Article Synopsis
  • Thousands of enhancers exist in the human genome, yet few are linked to cancer progression, particularly concerning resistance related to drug therapies that target oncokinases.
  • A specific enhancer located 63 kb downstream of the MET gene was found to interact with the MET promoter, which increases MET expression when BRAF is inhibited, suggesting a key role in cancer drug resistance.
  • The study identified that the transcription factor MITF controls this enhancer activity, and modifying the MITF motif can reduce chromatin looping, drug resistance, while still allowing melanoma cell differentiation.
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Aberrations of protein-coding genes are a focus of cancer genomics; however, the impact of oncogenes on expression of the ~50% of transcripts without protein-coding potential, including long noncoding RNAs (lncRNAs), has been largely uncharacterized. Activating mutations in the BRAF oncogene are present in >70% of melanomas, 90% of which produce active mutant BRAF(V600E) protein. To define the impacts of oncogenic BRAF on the melanocyte transcriptome, massively parallel cDNA sequencing (RNA-seq) was performed on genetically matched normal human melanocytes with and without BRAF(V600E) expression.

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Although our understanding of the molecular regulation of adult neovascularization has advanced tremendously, vascular-targeted therapies for tissue ischemia remain suboptimal. The master regulatory transcription factors of the hypoxia-inducible factor (HIF) family are attractive therapeutic targets because they coordinately up-regulate multiple genes controlling neovascularization. Here, we used an inducible model of epithelial HIF-1 activation, the TetON-HIF-1 mouse, to test the requirement for VEGF in HIF-1 mediated neovascularization.

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Neovascularization is a crucial component of tumor growth and ischemia. Although prior work primarily used disease models, delineation of neovascularization in the absence of disease can reveal intrinsic mechanisms of microvessel regulation amenable to manipulation in illness. We created a conditional model of epithelial HIF-1 induction in adult mice (TetON-HIF-1 mice).

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