406 results match your criteria: "Irell & Manella Graduate School of Biological Sciences of the City of Hope[Affiliation]"

Hypomethylating agents (HMAs), such as decitabine and 5-azacytidine (AZA), are valuable treatment options for patients with acute myeloid leukemia that are ineligible for intensive chemotherapy. Despite providing significant extensions in survival when used alone or in combination, eventual relapse and resistance to HMAs are observed. The mechanisms leading to these outcomes are still not well defined and may, in part, be due to a focus on leukemic populations with limited information on the effects of HMAs on non-leukemic cells in the blood and other tissue compartments.

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Myosin VI drives arrestin-independent internalization and signaling of GPCRs.

Nat Commun

December 2024

Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA.

G protein-coupled receptor (GPCR) endocytosis is canonically associated with β-arrestins. Here, we delineate a β-arrestin-independent endocytic pathway driven by the cytoskeletal motor, myosin VI. Myosin VI engages GIPC, an adaptor protein that binds a PDZ sequence motif present at the C-terminus of several GPCRs.

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Functions of PMS2 and MLH1 important for regulation of divergent repeat-mediated deletions.

DNA Repair (Amst)

November 2024

Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA. Electronic address:

Article Synopsis
  • Repeat-mediated deletions (RMDs) occur when repetitive DNA elements bridge breaks in DNA, leading to the loss of certain sequences; this process requires careful resolution of sequence differences between the repeats.
  • The MLH1 protein and its partner PMS2 are essential for both preventing RMDs and resolving sequence divergence in these deletions.
  • Mutant studies of MLH1 and PMS2 reveal distinct functions where some mutants show defects in both suppression and resolution, while others affect only one function, suggesting a complex relationship between these processes.
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Desmoplasia is a hallmark feature of pancreatic ductal adenocarcinoma (PDAC) that contributes significantly to treatment resistance. Approaches to enhance drug delivery into fibrotic PDAC tumors continue to be an important unmet need. In this study, we have engineered a tumor-colonizing -based agent that expresses both collagenase and hyaluronidase as a strategy to reduce desmoplasia and enhance the intratumoral perfusion of anticancer agents.

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BaNDyT: Bayesian Network modeling of molecular Dynamics Trajectories.

bioRxiv

November 2024

Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, 1218 S 5th Ave, Monrovia, CA 91016.

Bayesian network modeling (BN modeling, or BNM) is an interpretable machine learning method for constructing probabilistic graphical models from the data. In recent years, it has been extensively applied to diverse types of biomedical datasets. Concurrently, our ability to perform long-timescale molecular dynamics (MD) simulations on proteins and other materials has increased exponentially.

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Effects from aging in single cells are heterogenous, whereas at the organ- and tissue-levels aging phenotypes tend to appear as stereotypical changes. The mammary epithelium is a bilayer of two major phenotypically and functionally distinct cell lineages: luminal epithelial and myoepithelial cells. Mammary luminal epithelia exhibit substantial stereotypical changes with age that merit attention because these cells are the putative cells-of-origin for breast cancers.

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Adoptive T cell therapies for solid tumors: T(I)ME is of the essence.

EBioMedicine

November 2024

Irell and Manella Graduate School of Biological Sciences, City of Hope National Medical Center, Duarte, CA, United States; Department of Immunooncology, City of Hope National Medical Center, Duarte, CA, United States; Department of Pediatrics, City of Hope Children's Cancer Center, Duarte, CA, United States. Electronic address:

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Modified vaccinia Ankara (MVA) virus is a widely used vaccine platform, making accurate titration essential for vaccination studies. However, the current plaque forming unit (PFU) assay, the standard for MVA titration, is prone to observer bias and other limitations that affect accuracy and precision. To address these challenges, we developed a new flow cytometry-based quantification method using a highly specific monoclonal antibody (mAb) for the detection of MVA-infected cells, as a more accurate titration assay.

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Meibomian gland lipid alterations and ocular surface sequela in Awat2 knockout murine model of meibomian gland dysfunction and evaporative dry eye disease.

Ocul Surf

October 2024

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA; Department of Ophthalmology and Vision Science, School of Medicine, University of California-Davis, Davis, CA, 95616, USA. Electronic address:

Article Synopsis
  • There is a need for better animal models to study meibomian gland dysfunction (MGD) and evaporative dry eye disease (EDED), leading researchers to evaluate Awat2 knockout (KO) mice for this purpose.
  • The study involved various tests on both wildtype and Awat2 KO mice, including ocular examinations, lipid analysis, and gene expression assessments.
  • Results showed that Awat2 KO mice exhibited characteristics similar to human MGD and EDED, such as corneal issues and impaired meibum secretion, making them suitable for testing new treatments.
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Article Synopsis
  • Oncogenic mutations like those in KRAS cause transcription-replication conflicts (TRCs) in pancreatic ductal adenocarcinoma (PDAC), making them more common in these cancer cells than in other tumors or normal cells.
  • The study identifies base-excision repair (BER) factors as key regulators of TRCs, with BER inhibitors increasing TRCs by disrupting RNA polymerase II and R-loop dynamics.
  • Combining ATR and BER inhibitors shows promise in enhancing DNA damage and reducing PDAC cell growth, emphasizing the therapeutic potential of targeting these pathways in cancer treatment.
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Tumor draining lymph nodes (TDLN) represent a key component of the tumor-immunity cycle. There are few studies describing how TDLNs impact lymphocyte infiltration into tumors. Here we directly compare tumor-free TDLNs draining "cold" and "hot" human triple negative breast cancers (TDLN and TDLN).

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Article Synopsis
  • Epstein-Barr virus (EBV) is linked to various cancers and diseases, yet despite extensive research, an effective vaccine has not been licensed, largely due to past efforts focusing on a single protein.
  • The study presents a new vaccine, MVA-EBV5-2, targeting five EBV entry glycoproteins, demonstrating genetic stability and the ability to produce strong immune responses in animal models.
  • Results showed that this vaccine generated higher levels of neutralizing antibodies in mice and rhesus macaques compared to traditional methods, effectively reducing EBV infection in treated models.
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A key step of Canonical Nonhomologous End Joining (C-NHEJ) is synapsis of DNA double strand break (DSB) ends for ligation. The DNA-PKcs dimer mediates synapsis in a long-range complex with DSB ends remaining apart, whereas the XLF homodimer can mediate synapsis in both long-range and short-range complexes. Recent structural studies found the PAXX homodimer may also facilitate synapsis in long-range complexes with DNA-PKcs via its interactions with Ku70.

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Article Synopsis
  • SF3B1 is a critical RNA splicing gene frequently mutated in cancer, but studying its pathogenic effects has been challenging due to the lack of suitable cell line models.
  • By comparing various genome editing techniques, the study found that prime editing, specifically using PE5max, was the most effective method for introducing the SF3B1 K700E mutation in multiple cell lines.
  • The researchers introduced this mutation into chronic lymphocytic leukemia cell lines using a novel approach called PRECIS, which not only mimicked key mutant characteristics but also revealed new insights into the mutation's role in cancer progression and genome instability.
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Repeat-mediated deletions (RMDs) are a type of deletion rearrangement that utilizes two repetitive elements to bridge a DNA double-strand break (DSB) that leads to loss of the intervening sequence and one of the repeats. Sequence divergence between repeats causes RMD suppression and indeed this divergence must be resolved in the RMD products. The mismatch repair factor, MLH1, was shown to be critical for both RMD suppression and a polarity of sequence divergence resolution in RMDs.

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Diabetes mellitus (DM) is a metabolic disease that heightens the risks of many vascular complications, including peripheral arterial disease (PAD). Various types of cells, including but not limited to endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and macrophages (MΦs), play crucial roles in the pathogenesis of DM-PAD. Long non-coding RNAs (lncRNAs) are epigenetic regulators that play important roles in cellular function, and their dysregulation in DM can contribute to PAD.

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Isolation of Mouse Pancreatic Endothelial Cells.

J Vis Exp

June 2024

Irell and Manella Graduate School, City of Hope; Department of Diabetes Complications and Metabolism, City of Hope;

The pancreas is a vital organ for maintaining metabolic balance within the body, in part due to its production of metabolic hormones such as insulin and glucagon, as well as digestive enzymes. The pancreas is also a highly vascularized organ, a feature facilitated by the intricate network of pancreatic capillaries. This extensive capillary network is made up of highly fenestrated endothelial cells (ECs) important for pancreas development and function.

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Article Synopsis
  • The third intracellular loop (ICL3) of the β2-adrenergic receptor is flexible and shifts between open and closed states, which is important for how it interacts with G proteins.
  • Lipid molecules, specifically phosphatidylinositol 4,5-bisphosphate (PIP2), help stabilize the receptor in its active form by keeping ICL3 open, leading to a tilting of the receptor in the membrane.
  • The ganglioside GM3 also affects receptor function by interacting with its extracellular loops, showing that lipids play a crucial role in the behavior and configuration of GPCRs.
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The human alkylation B (AlkB) homologs, ALKBH2 and ALKBH3, respond to methylation damage to maintain genomic integrity and cellular viability. Both ALKBH2 and ALKBH3 are direct reversal repair enzymes that remove 1-methyladenine (1meA) and 3-methylcytosine (3meC) lesions commonly generated by alkylating chemotherapeutic agents. Thus, the existence of deficiencies in ALKBH proteins can be exploited in synergy with chemotherapy.

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Exocrine-to-endocrine cross talk in the pancreas is crucial to maintain β-cell function. However, the molecular mechanisms underlying this cross talk are largely undefined. Trefoil factor 2 (Tff2) is a secreted factor known to promote the proliferation of β-cells in vitro, but its physiological role in vivo in the pancreas is unknown.

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In mammalian cells, DNA double-strand breaks are predominantly repaired by non-homologous end joining (NHEJ). During repair, the Ku70-Ku80 heterodimer (Ku), X-ray repair cross complementing 4 (XRCC4) in complex with DNA ligase 4 (X4L4) and XRCC4-like factor (XLF) form a flexible scaffold that holds the broken DNA ends together. Insights into the architectural organization of the NHEJ scaffold and its regulation by the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) were recently obtained by single-particle cryo-electron microscopy analysis.

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Unlabelled: Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8, is the causal agent of Kaposi sarcoma, a cancer that appears as tumors on the skin or mucosal surfaces, as well as primary effusion lymphoma and KSHV-associated multicentric Castleman disease, which are B-cell lymphoproliferative disorders. Effective prophylactic and therapeutic strategies against KSHV infection and its associated diseases are needed. To develop these strategies, it is crucial to identify and target viral glycoproteins involved in KSHV infection of host cells.

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Bayesian network models identify cooperative GPCR:G protein interactions that contribute to G protein coupling.

J Biol Chem

June 2024

Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, California, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, California, USA. Electronic address:

Cooperative interactions in protein-protein interfaces demonstrate the interdependency or the linked network-like behavior and their effect on the coupling of proteins. Cooperative interactions also could cause ripple or allosteric effects at a distance in protein-protein interfaces. Although they are critically important in protein-protein interfaces, it is challenging to determine which amino acid pair interactions are cooperative.

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4S-fluorination of ProB29 in insulin lispro slows fibril formation.

J Biol Chem

June 2024

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA. Electronic address:

Recombinant insulin is a life-saving therapeutic for millions of patients affected by diabetes mellitus. Standard mutagenesis has led to insulin variants with improved control of blood glucose; for instance, the fast-acting insulin lispro contains two point mutations that suppress dimer formation and expedite absorption. However, insulins undergo irreversible denaturation, a process accelerated for the insulin monomer.

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The role of bile acids in human aging.

Med Rev (2021)

April 2024

Department of Diabetes Complications and Metabolism, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA.

Bile acids are recognized as important signaling molecules that enable fine-tuned inter-communication from the liver, through the intestine, to virtually any organ, thus encouraging their pleiotropic physiological effects. Aging is a complex natural process defined as a progressive decline in cellular and organismal functions. A causal link between bile acids and the aging process is emerging.

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