Biology subjects

Mollaoglu, G.

Publications and source records attributed to Mollaoglu, G..

4 recordsLinked to original sources

bioRxiv2025

Plasminogen activator inhibitors orchestrate the immunosuppressive tumor microenvironment in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense extracellular matrix (ECM) that sustains an immunosuppressive tumor microenvironment (TME). While this protective niche has been described, the molecular determinants orchestrating its formation and dictating its immune interactions are not well defined. Using Perturb-map, we determine how dozens of different gene perturbations shape the growth and cellular environments of PDAC clones through space and time. Our study reveals dynamic, gene-specific adaptations of immune neighborhoods during clonal selection. We identified Serpinb2 (PAI2) and Serpine1 (PAI1) as key cancer-derived mediators of TME remodeling and immune evasion. These factors promote the deposition of a fibrin-rich ECM that shapes immune cell composition, locally retains and polarizes immunosuppressive macrophages and excludes cytotoxic T cells. Deletion of either Serpinb2 or Serpine1 greatly enhanced tumor response to anti-PD1 immunotherapy in an aggressive PDAC model. Transcriptomic analysis further linked their expression to distinct PDAC subtypes and poor patient survival. Our findings demonstrate that Serpinb2 and Serpine1 establish a permissive niche for tumor progression and show how PDAC cells exploit components of the fibrinolysis pathway to remodel the ECM, alter macrophage composition, and protect themselves from immune editing, ultimately reinforcing the role of extracellular factors in shaping an immune-privileged tumor niche.

cancer biology↗

bioRxiv2024

Bispecific antibody targeting of lipid nanoparticles

Lipid nanoparticles (LNP) are the most clinically advanced non-viral gene delivery system. While progress has been made for enhancing delivery, cell specific targeting remains a challenge. Targeting moieties such as antibodies can be chemically-conjugated to LNPs however, this approach is complex and has challenges for scaling up. Here, we developed an approach to generate antibody-conjugated LNPs that utilizes a bispecific antibody (bsAb) as the targeting bridge. As a docking site for the bsAb, we generated LNPs with a short epitope, derived from hemagglutinin antigen (HA), embedded in the PEG component of the particle (LNPHA). We generated bsAb in which one domain binds HA and the other binds different cell surface proteins, including PD-L1, CD4, CD5, and SunTag. Non-chemical conjugation of the bsAb and LNP resulted in a major increase in the efficiency and specificity of transfecting cells expressing the cognate target. LNP/bsAb mediated a 4-fold increase in in vivo transfection of PD-L1 expressing cancer cells, and a 26-fold increase in ex vivo transfection of quiescent primary human T cells. Additionally, we created a universal bsAb recognizing HA and anti-rat IgG2, enabling LNP tethering to off-the-shelf antibodies such as CD4, CD8, CD20, CD45, and CD3. By utilizing a molecular dock and bsAb technology, these studies demonstrate a simple and effective strategy to generate antibody-conjugated LNPs, enabling precise and efficient mRNA delivery.

bioengineering↗

bioRxiv2021

Targeting macrophages with CAR-T cells delays solid tumor progression and enhances anti-tumor immunity

Tumor-associated macrophages (TAMs) are one of the most abundant cell types in many solid tumors and typically exert protumor effects. This has led to an interest in macrophage-depleting agents for cancer therapy, but approaches developed to date have had limited success in clinical trials. Here, we report the development of a strategy for TAM depletion in mouse solid tumor models using chimeric antigen receptor (CAR) T cells targeting the macrophage marker F4/80 (F4.CAR-T). F4.CAR-T cells effectively killed macrophages in vitro and in vivo without toxicity. When injected into mice bearing orthotopic lung tumors, F4.CAR-T cells infiltrated tumor lesions and delayed tumor growth comparably to PD1 blockade, and significantly extended mouse survival. Anti-tumor effects were mediated by F4.CAR-T-produced IFN-{gamma}, which promoted upregulation of MHC molecules on cancer cells and tumor-infiltrating myeloid cells. Notably, F4.CAR-T promoted expansion of endogenous CD8 T cells specific for tumor-associated antigens and led to immune editing of highly antigenic tumor cell clones. Antitumor impact was also observed in mouse models of ovarian and pancreatic cancer. These studies provide proof-of-principle evidence to support CAR-T targeting of TAMs as a means to enhance antitumor immunity.

immunology↗

bioRxiv2021

P53 is a direct regulator of the immune co-stimulatory molecule CD80

Increasing evidence indicates oncogenes and tumor suppressors not only influence cell fitness but can also control the immunophenotype of cells. Here, we examined how 34 commonly mutated genes in colorectal cancer (CRC) may influence the expression of 8 key immunomodulatory proteins. To do this, we employed a functional genomics approach utilizing Pro-Code/CRISPR libraries for high-dimensional analysis. We introduced a library of 102 Pro-Code/gRNA combinations, targeting each of the 34 genes, in CT26 cells, a CRC cell model, and measured the expression of each of the immunomodulatory proteins by CyTOF mass cytometry. Notably, cells carrying a Pro-Code/CRISPR targeting the Trp53 lost expression of the immune co-stimulatory molecule CD80. Validation confirmed that Trp53 knockout resulted in the loss of CD80 and that activation of P53, through DNA damage or stabilization, resulted in CD80 upregulation. P53 ChIP-seq identified the CD80 promoter as a direct target of P53. CD80 regulation by P53 was identified in other cells, including normal epithelial cells and macrophages. Functionally, CD80 reduction caused by P53 loss led to a reduced capacity for CRC to prime antigen-specific T cells. These studies establish CD80, a canonical co-stimulatory molecule, as a direct target of the tumor suppressor and DNA damage response gene, P53.

immunology↗