Alexander Pietras Lab

Spatial and temporal dynamics of cancer-associated fibroblast niches in breast cancer - Breast Cancer Research Breast Cancer Research - Cancer-associated fibroblasts (CAFs) are the main constituents of the tumor microenvironment. Several studies have delineated CAF heterogeneity in different types of...

New paper out from the @kpietraslab.bsky.social lab.
I am happy to share that my first-author paper is now published. We map the spatial and temporal dynamics of cancer-associated fibroblasts in breast cancer using integrated spatial proteomics and transcriptomics.
link.springer.com/article/10.1...

Coevolution of neoplastic and non-neoplastic reactive astrocyte states converges on mesenchymal-like and injury-response programs during murine glioblastoma progression and post-radiotherapy recurrenc... Glioblastomas initially respond to radiotherapy but invariably recur, often within high-dose radiation treatment fields. Although stromal radiation responses are incompletely understood, evidence sugg...

📣 PREPRINT ALERT! Glioblastoma (GBM) often responds to radiotherapy, yet almost always recurs, frequently within high-dose radiation fields. www.biorxiv.org/content/10.6...

Check this out👇
Our neighbors @pietraslab.bsky.social has just published a new preprint detailing high-resolution profiling of the irradiated GBM microenvironment. ❄️Cool reading for the holidays❄️ Thanks for including us!

Thanks to collaborators @kpietraslab.bsky.social, @jonssonmelanomalab.bsky.social and @erc.europa.eu, Swedish Cancer Society, @vetenskapsradet.bsky.social, Swedish Childhood Cancer Fund, and Mrs. Berta Kamprad's Cancer Foundation (L2CancerBridge) for funding!

Targeting reactive astrocyte-like states or their intercellular signaling may represent a strategy to disrupt GBM recurrence after radiotherapy.

This convergence suggests a new angle on radioresistance: not just intrinsic tumor cell survival, but injury-response states shared across the TME.

Reactive astrocyte programs converge in both astrocytes and tumor cells after radiotherapy, potentially creating a permissive niche for GBM recurrence.

These reactive astrocyte-like tumor cells engage in receptor–ligand crosstalk with reactive astrocytes, involving known and putative drivers of aggressiveness and therapy resistance.

After radiotherapy, tumor cells with reactive astrocyte-like programs - enriched for mesenchymal and injury-response signatures - expand and persist in recurrent tumors.

We found that astrocyte states track with disease stage. We observed reactive non-neoplastic astrocytes as well as tumor cells that adopt reactive astrocyte-like phenotypes.

Across 13 non-neoplastic cell types and 10 tumor cell states, we mapped transcriptional changes during progression from healthy brain → primary GBM → recurrent GBM.

To dissect this, we used a genetically engineered mouse model of GBM and profiled healthy brain, primary tumors, and post-radiotherapy recurrences using single-cell + spatial transcriptomics and IHC.

Growing evidence suggests radiotherapy doesn’t just affect tumor cells, it reshapes the tumor microenvironment (TME) in ways that may support recurrence.

Coevolution of neoplastic and non-neoplastic reactive astrocyte states converges on mesenchymal-like and injury-response programs during murine glioblastoma progression and post-radiotherapy recurrenc... Glioblastomas initially respond to radiotherapy but invariably recur, often within high-dose radiation treatment fields. Although stromal radiation responses are incompletely understood, evidence sugg...

📣 PREPRINT ALERT! Glioblastoma (GBM) often responds to radiotherapy, yet almost always recurs, frequently within high-dose radiation fields. www.biorxiv.org/content/10.6...

Pericytes orchestrate a tumor-restraining microenvironment in glioblastoma - Nature Communications Improved understanding of the tumor ecosystem in glioblastoma is critical for developing new treatment strategies for the disease. Here, the authors identify pericytes as an active paracrine signaling...

New paper alert 🚨
We are delighted to present our latest paper in @natcomms.nature.com through fabulous work from co-first authors Sebastian Braun and Paulina Bolivar! Big thanks to all expert collaborators for taking this long journey with us!
Tweetorial in comments 🧵
www.nature.com/articles/s41...

Pericytes orchestrate a tumor-restraining microenvironment in glioblastoma - Nature Communications Improved understanding of the tumor ecosystem in glioblastoma is critical for developing new treatment strategies for the disease. Here, the authors identify pericytes as an active paracrine signaling...

Really excited to see this new paper from our friends & neighbors in the other Pietras lab @kpietraslab.bsky.social, uncovering surprising (?) roles of pericytes in the GBM microenvironment. Congrats all, and thanks for including us! www.nature.com/articles/s41...

Pericytes orchestrate a tumor-restraining microenvironment in glioblastoma - Nature Communications Improved understanding of the tumor ecosystem in glioblastoma is critical for developing new treatment strategies for the disease. Here, the authors identify pericytes as an active paracrine signaling...

Really excited to see this new paper from our friends & neighbors in the other Pietras lab @kpietraslab.bsky.social, uncovering surprising (?) roles of pericytes in the GBM microenvironment. Congrats all, and thanks for including us! www.nature.com/articles/s41...

Postdoctoral Researcher in "Cancer Neuroscience: the impact of neural activity on 3D genome organization and cellular plasticity in glioblastoma”

Excited to share I’ve received a #SSMF #Consolidator grant!

📣 Recruiting a #postdoc to study #cancer #neuroscience #3Dgenomics #multiomics #singlecellomics

🔬How neural inputs shape #3Dgenome and #cellplasticity in #glioblastoma #GBM

Interested? Apply now 👇
rb.gy/m7xz7b

Fantastic news, Silvia! Congrats!

How can senescent cells, which are damaged and growth arrested, both block tumor initiation as well as fuel its growth? A recent study published in Cancer Discovery @aacrjournals.bsky.social from Lin Zhou in the lab uncovered some new insights into this puzzle.
aacrjournals.org/cancerdiscov...

Thanks to all speakers, including bsky users @winklerlab.bsky.social @claudiakleinman.bsky.social @nelander-lab.bsky.social @gocastelobranco.bsky.social, the Ragnar Söderberg foundation, and co-hosts @remeseiro-lab.bsky.social, @maawim.bsky.social, and Fredrik Swartling.

Had a blast hosting the Brain Tumor Plasticity symposium at the Royal Swedish Academy of Sciences this week! Here's @leilaakkari.bsky.social with an outstanding talk on the evolving brain tumor microenvironment 🤩

Thrilled to share our latest work - we describe a novel and therapeutically relevant mechanism underlying dysregulation of innate immune receptor C5aR1 in the tumour microenvironment. Thanks and congratulations to all authors!

www.nature.com/articles/s41...

To this day, even the strongest treatments fail when the brain’s own healing turns against it. Flunarizine, a migraine drug, may help stop astrocytes from nurturing #glioblastoma back to life.

Read ⤵️

Phenotypic Screening Identifies Flunarizine as an Inhibitor of Radiotherapy-Induced Astrocyte Reactivity with Therapeutic Potential in Glioblastoma Radiotherapy is part of the standard-of-care for glioblastoma, yet tumors invariably recur as incurable lesions post-treatment. Recent studies suggest that radiation-induced astrocyte reactivity foste...

📣 Preprint alert! Happy to share our latest work, in which we identify Flunarizine as an inhibitor of astrocyte reactivity with therapeutic potential in glioblastoma (GBM). Details in 🧵:
www.biorxiv.org/content/10.1...

Phenotypic Screening Identifies Flunarizine as an Inhibitor of Radiotherapy-Induced Astrocyte Reactivity with Therapeutic Potential in Glioblastoma https://www.biorxiv.org/content/10.1101/2025.07.12.664538v1

#Glioblastoma #GBM #AstrocyteReactivity #DrugRepurposing #Radiotherapy #NeuroOncology

…the Swedish Cancer Society, the Swedish Research Council, the Swedish Childhood Cancer Fund, Ollie & Elof Ericssons foundation, the Crafoord foundation, the Swedish Brain Foundation, the Royal Physiographic Society in Lund, Stiftelsen Cancera, @embo.org, and the Fondation Bettencourt-Schueller.

This work was spearheaded by Pauline Jeannot with crucial contributions from collaborators @edinburgh-uni.bsky.social @lundstem.bsky.social @ahleniuslab.bsky.social , and supported by @erc.europa.eu, Mrs. Berta Kamprad's Cancer Foundation, the Ragnar Söderberg Foundation…

Our findings position Flunarizine as a clinically viable repurposed drug to target RT-induced astrocyte reactivity, delaying recurrence in preclinical models.