Publications by authors named "Amir Vajdi"

Epithelial-to-mesenchymal transition (EMT) is associated with tumor initiation, metastasis, and drug resistance. However, the mechanisms underlying these associations are largely unknown. We studied several tumor types to identify the source of EMT gene expression signals and a potential mechanism of resistance to immuno-oncology treatment.

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Article Synopsis
  • Human cancers, including small cell lung cancer (SCLC), often show re-expression of germline factors like DDX4, which is linked to enhanced cell motility and resistance to the chemotherapy drug cisplatin.
  • DDX4 appears to upregulate proteins involved in DNA repair and immune/inflammatory responses, suggesting its role in promoting tumor growth and survival.
  • Higher levels of DDX4 in SCLC patients are associated with poorer survival rates, indicating that DDX4 may help cancer cells survive by boosting pathways related to DNA damage response and immune evasion, especially during chemotherapy.
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Unlabelled: Immunotherapy has shown limited efficacy in patients with EGFR-mutated lung cancer. Efforts to enhance the immunogenicity of EGFR-mutated lung cancer have been unsuccessful to date. Here, we discover that MET amplification, the most common mechanism of resistance to third-generation EGFR tyrosine kinase inhibitors (TKI), activates tumor cell STING, an emerging determinant of cancer immunogenicity (1).

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Some small cell lung cancers (SCLCs) are highly sensitive to inhibitors of the histone demethylase LSD1. LSD1 inhibitors are thought to induce their anti-proliferative effects by blocking neuroendocrine differentiation, but the mechanisms by which LSD1 controls the SCLC neuroendocrine phenotype are not well understood. To identify genes required for LSD1 inhibitor sensitivity in SCLC, we performed a positive selection genome-wide CRISPR/Cas9 loss of function screen and found that ZFP36L1, an mRNA-binding protein that destabilizes mRNAs, is required for LSD1 inhibitor sensitivity.

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Evolve and resequencing (E&R) was applied to lab adaptation of Toxoplasma gondii for over 1,500 generations with the goal of mapping host-independent virulence traits. Phenotypic assessments of steps across the lytic cycle revealed that only traits needed in the extracellular milieu evolved. Nonsynonymous single-nucleotide polymorphisms (SNPs) in only one gene, a P4 flippase, fixated across two different evolving populations, whereas dramatic changes in the transcriptional signature of extracellular parasites were identified.

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Neuroendocrine to nonneuroendocrine plasticity supports small cell lung cancer (SCLC) tumorigenesis and promotes immunogenicity. Approximately 20% to 25% of SCLCs harbor loss-of-function (LOF) mutations. Previous studies demonstrated that NOTCH functions as a SCLC tumor suppressor, but can also drive nonneuroendocrine plasticity to support SCLC growth.

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Introduction: STK11 and KEAP1 mutations (STK11 mutant [STK11] and KEAP1) are among the most often mutated genes in lung adenocarcinoma (LUAD). Although STK11 has been associated with resistance to programmed death-(ligand)1 (PD-[L]1) inhibition in KRAS LUAD, its impact on immunotherapy efficacy in KRAS wild-type (KRAS) LUAD is currently unknown. Whether KEAP1 differentially affects outcomes to PD-(L)1 inhibition in KRAS and KRAS LUAD is also unknown.

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Article Synopsis
  • Small cell lung carcinoma (SCLC) has a high mutation rate but typically shows a low response to immune checkpoint blockade (ICB) treatments, meaning it's hard to treat effectively with current immunotherapies.
  • Researchers discovered a specific group of SCLC cells that increase MHC I levels, which helps enhance the effectiveness of ICB, indicating a connection between loss of neuroendocrine traits and improved immune response.
  • The study suggests that using EZH2 inhibitors to change cell characteristics, alongside STING agonists, could boost T-cell activity against SCLC, presenting new strategies for treatment based on the tumor's immune properties.
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Resistance to oncogene-targeted therapies involves discrete drug-tolerant persister cells, originally discovered through in vitro assays. Whether a similar phenomenon limits efficacy of programmed cell death 1 (PD-1) blockade is poorly understood. Here, we performed dynamic single-cell RNA-Seq of murine organotypic tumor spheroids undergoing PD-1 blockade, identifying a discrete subpopulation of immunotherapy persister cells (IPCs) that resisted CD8+ T cell-mediated killing.

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Eradicating tumor dormancy that develops following epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment of EGFR-mutant non-small cell lung cancer, is an attractive therapeutic strategy but the mechanisms governing this process are poorly understood. Blockade of ERK1/2 reactivation following EGFR TKI treatment by combined EGFR/MEK inhibition uncovers cells that survive by entering a senescence-like dormant state characterized by high YAP/TEAD activity. YAP/TEAD engage the epithelial-to-mesenchymal transition transcription factor SLUG to directly repress pro-apoptotic BMF, limiting drug-induced apoptosis.

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Motivation: Over the past decade, there have been impressive advances in determining the 3D structures of protein complexes. However, there are still many complexes with unknown structures, even when the structures of the individual proteins are known. The advent of protein sequence information provides an opportunity to leverage evolutionary information to enhance the accuracy of protein-protein interface prediction.

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