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Laternser, S.

Publications and source records attributed to Laternser, S..

2 recordsLinked to original sources
bioRxiv2025

Mapping Tumor Microenvironment and Treatment Response of Diffuse Midline Glioma Using Multiplexed Immunofluorescence and AI Models

BackgroundDespite its clinical promise in non-solid tumor, immunotherapy is yet to show significant clinical efficacy for brain tumors including pediatric diffuse midline glioma (DMG). This indicated the need to fully explore DMG immune tumor microenvironment (TME). MethodWhole brains (49 DMGs, 20 non-DMG, 10 non-malignant) from 79 pediatric patients were used to establish a tissue microarray (918 cores) representing primary, metastatic, and adjacent healthy sites. CellDIVE MxIF multiplex assay was used to probe for 33 immune and cell type markers. RNA sequencing (n=62 patients) defined additional immune signatures. Findings were validated using patient plasma and DMG PDX models. Our annotated single-cell atlas was used to train a spatial AI model to predict antigens from H&E staining. FindingsWe found enrichment of M1-activated microglia in primary versus adjacent healthy tissue. PD1 positive cells were significantly (p<0.01) higher in tumor compared to adjacent controls. This was validated by mRNA profiling, further indicating two distinct groups with top 35 significant (p<0.05) genes revealing synaptic signature in the metastatic cohort. We stratified the patient cohort by treatment. Imipridone cohort (n=5) showed decreased progenitor (Nestin+, Vimentin+, and SOX2+) and increased macrophages/microglia infiltration. Increased T and B cells was validated in patient plasma following imipridone therapy. Combination therapy of imipridone and immunotherapy (n=7) resulted in increased myeloid (Iba1, CD68, CD163) and lymphoid (CD3, CD8) cells. Enhanced immune engagement was validated in DMG PDX models. Machine learning resulted in a spatial AI model capable of predicting 22 antigens using H&E slides. InterpretationsDMG tumors maintain a cold immune microenvironment, which is nevertheless dynamic and responsive to therapy, indicating the need to explore combination therapies. AI-assisted antigen detection is suitable for rapid interpretation of clinical biospecimens. FundingThis work was supported by Rising Tide, SNF, LilaBean Foundation, Swifty Foundation, Swiss to Cure DIPG and Yuvaan Tiwari Foundation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=45 SRC="FIGDIR/small/644698v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@198b382org.highwire.dtl.DTLVardef@312e0forg.highwire.dtl.DTLVardef@c71b82org.highwire.dtl.DTLVardef@1df1c35_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

cancer biology↗
bioRxiv2023

PI3K/mTOR is a therapeutically targetable genetic dependency in diffuse intrinsic pontine glioma

Diffuse midline glioma (DMG), including tumors diagnosed in the brainstem (diffuse intrinsic pontine glioma - DIPG), are uniformly fatal brain tumors that lack effective pharmacological treatment. Analysis of pooled CRISPR-Cas9 loss-of-function gene deletion screen datasets, identified PIK3CA and MTOR as targetable molecular dependencies across DIPG patient derived models, highlighting the therapeutic potential of the blood-brain barrier penetrant PI3K/Akt/mTOR inhibitor paxalisib. At the human equivalent maximum tolerated dose, mice treated with paxalisib experienced systemic feedback resulting in increased blood glucose and insulin levels, commensurate with DIPG patients in Phase 1b clinical trials who experienced hyperglycemia/hyperinsulinemia. To exploit genetic dependences, but maintain compliance and benefit, we optimized a paxalisib treatment regimen that employed reduced dosing more frequently, in combination with the anti-hyperglycemic drug, metformin. Combining optimized dosing with metformin restored glucose homeostasis and decreased phosphorylation of the insulin receptor in vivo, a common mechanism of PI3K-inhibitor resistance, extending the survival of DIPG xenograft models. RNA sequencing and phosphoproteomic profiling of DIPG models treated with paxalisib identified increased calcium-activated PKC signaling. Using the brain penetrant PKC inhibitor, enzastaurin in combination with paxalisib, we synergistically extended the survival of orthotopic xenograft models, benefits further promoted by metformin; thus, identifying a clinically relevant DIPG combinatorial approach. Brief SummaryDiffuse intrinsic pontine glioma is a lethal childhood brain tumor. Here we identify PIK3CA as a genetic dependency targeted by the brain penetrant pan-PI3K-inhibitor paxalisib.

cancer biology↗