Biology subjects

Flietner, E.

Publications and source records attributed to Flietner, E..

3 recordsLinked to original sources

bioRxiv2025

A live tumor fragment platform to assess immunotherapy response in core needle biopsies while addressing challenges of tumor heterogeneity

BackgroundImmune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, providing durable and even curative responses. However, most patients do not respond and current biomarkers (eg, programmed death ligand (PD-L1), mismatch repair deficiency (dMMR)/high microsatellite instability (MSI) and tumor mutational burden) lack predictive accuracy. Ex vivo profiling of patient-derived tumor fragments shows promise as a predictive biomarker but relies on substantial surgical tissue to mitigate intra-specimen heterogeneity. Innovations are needed that address these challenges, particularly where limited tissue is available in core needle biopsies (CNBs). MethodsLive tumor fragments (LTFs) were generated from 59 human tumor resections and 31 CNBs from patients enrolled in observational clinical trials (ClinicalTrials.gov identifiers: NCT05478538, NCT05520099, NCT06349642) to assess cytokine induction following ICI treatment. LTFs were encapsulated in hydrogel and cultured ex vivo for up to 72 hours. A sequential treatment strategy that applies control and treatment within the same well was used with response to ICI or CD3/CD28 assessed using a multiplex secretome assay. Viability was assessed using established metabolic assays and dynamic optical coherence microscopy. ResultsLTFs maintained viability and retained T cells responsive to stimulation throughout ex vivo culture. Multiplex immunofluorescence and immunohistochemistry showed key components of the tumor microenvironment, including relative proportions of CD4+ and CD8+ immune cell populations, were preserved. Specimens positive for PD-L1 or dMMR/MSI-high were enriched for cytokine upregulation, including T-cell response cytokines IFN{gamma} and CXCL10, after PD-1 treatment. To demonstrate clinical applicability of the sequential treatment strategy, CNBs from patients with lung, gastrointestinal or kidney cancer were profiled and differential cytokine induction in response to ICI treatment was observed. ConclusionsThe novel ex vivo platform presented is capable of detecting T-cell response to ICI treatment by using a sequential treatment strategy. This approach addresses challenges associated with cross-well heterogeneity in tissue composition and requires half as much tissue as a cross-well comparison, mitigating tissue limitations typically associated with non-surgical biopsies. Importantly, the platform is compatible with established functional assays as well as non-destructive spatial imaging, enabling researchers to characterize response to ICI longitudinally. Ongoing trials will enable clinicians to assess platform performance in predicting response to immunotherapy.

cancer biology↗

bioRxiv2022

Genomic and transcriptional profiling stratifies VQ myeloma lines into two clusters with distinct risk signatures and drug responses

Multiple myeloma (MM) is a cancer of malignant plasma cells in the bone marrow and extramedullary sites. We previously characterized a VQ model for human high-risk MM. Different VQ lines display distinct disease phenotypes and survivals, suggesting significant intra-model variation. Here, we use whole exome sequencing and copy number variation (CNV) analysis coupled with RNA-Seq to stratify VQ lines into corresponding clusters: Cluster I VQ cells carried recurrent amplification of chromosome (chr) 3 and displayed upregulation of growth pathways and high-risk myeloma gene signatures, whereas Cluster II cells had monosomy chr5 and overexpressed genes and pathways associated with positive response to bortezomib (Btz) treatment in human MM patients. Consistently, in sharp contrast to Cluster II VQ cells that showed short-term response to Btz, Cluster I VQ cells were de novo resistant to Btz in vivo. Our study highlights Cluster I VQ lines as highly representative of human high-risk MM subset.

cancer biology↗

bioRxiv2018

Versican Proteolysis Predicts Immune Effector Infiltration And Post-Transplant Survival In Myeloma

High-dose alkylator-based conditioning followed by autologous stem-cell transplantation (ASCT) is a therapeutic mainstay for eligible patients with multiple myeloma. However, post-transplant relapses are common and prognostic biomarkers are scarce. Relapses are characterized by the influx of regulatory myeloid cells and dysfunctional T effectors. We have shown that myeloma-infiltrating myeloid cells produce versican (VCAN), a large matrix proteoglycan with tolerogenic activities. VCAN proteolysis by a-disintegrin-and-metalloproteinase-with-thrombospondin-motifs (ADAMTS) proteases generates versikine, a bioactive fragment (\"matrikine\") that regulates Batf3-dendritic cells, known to control CD8+-attracting chemokine networks. Here we demonstrate that intense VCAN proteolysis predicts CD8+ infiltration post-transplant and paradoxically portends significantly inferior survival outcomes. Our data suggest that VCAN proteolysis promotes the influx of CD8+ effectors that are rendered overwhelmingly dysfunctional and/or frankly immunoregulatory (CD8+ Treg) at the tumor site. Thus, complex immunosuppressive circuits orchestrated through VCAN accumulation and turnover generate conditions favorable for myeloma tumor regrowth and point to a readily-assayed biomarker to identify the patients at risk for relapse and early death. The dismal outcomes associated with VCAN proteolysis may be rationally overcome through immunotherapies such as checkpoint inhibition (e.g., anti-TIGIT), tumor vaccines or anti-myeloid (e.g., anti-CSF-1R) approaches.

immunology↗