Molecular Pathways Linked to Chemotherapy Resistance

What if cancer cells don’t just repair DNA damage, but actively decide when to stop? Our latest work in Nature Portfolio Cell Death & Disease uncovers a compelling systems-level mechanism linking metabolism to DNA repair: an ATM–AMPK–Wip1 feedback loop that dynamically controls how long DNA damage signals persist. Link: https://lnkd.in/giiWFrcF At first glance, DDR (DNA damage response) is often taught as a linear pathway. But biology rarely operates in straight lines. Instead, we show that: • DNA damage activates ATM • ATM engages AMPK, the cell’s metabolic sensor • AMPK stabilizes Wip1 • Wip1, in turn, shuts down ATM A closed loop. A regulatory circuit. A decision-making module. Why is this exciting? Because this loop acts like a molecular timer—fine-tuning how long a cell “keeps the alarm on” after DNA damage. And in cancer, this timing is everything. Under metabolic stress (a hallmark of tumors), this circuit can: → Accelerate DNA repair shutdown → Help cancer cells survive radiation and chemotherapy → Drive therapy resistance This also helps resolve a long-standing paradox: Why does AMPK sometimes suppress tumors, but in other contexts support their survival? The answer may lie not in AMPK alone, but in the network it participates in. From a translational perspective, one insight stands out: • Wip1 emerges as a precise therapeutic target Instead of broadly inhibiting metabolism (which comes with systemic toxicity), targeting Wip1 could selectively: • Prolong DNA damage signaling • Reinstate checkpoint control (p53, p38) • Sensitize tumors to treatment More broadly, this work reinforces a key idea in modern biology: Cells don’t just use pathways, they compute through circuits. Understanding these circuits is where the next breakthroughs in cancer therapy will come from. Curious to hear thoughts from others working at the intersection of metabolism, DDR, and systems biology. #CancerResearch #SystemsBiology #DNARepair #Metabolism #DDR #PrecisionOncology #Bioinformatics #TranslationalScience

Overcoming Glioblastoma Resistance to Chemotherapy: New Insights into Temozolomide Resistance Overview: Despite ongoing research, glioblastoma remains one of the deadliest brain cancers, with temozolomide (TMZ) serving as the frontline chemotherapy drug. While TMZ effectively penetrates the brain and induces DNA damage in cancer cells, tumor resistance mechanisms often render the treatment ineffective. Researchers from the Center for Genomic Integrity (IBS) and Ulsan National Institute of Science and Technology (UNIST) in South Korea have uncovered key insights into how glioblastomas evade TMZ’s effects, offering new hope for improved therapies. How Temozolomide (TMZ) Works — and Why It Fails: • Mechanism of Action: TMZ damages cancer cell DNA by adding a methyl group to guanine bases (O6-methylguanine or O6-meG), disrupting the cell’s ability to replicate. • Expected Outcome: In a successful scenario, this damage triggers cell death (apoptosis) in cancer cells. • The Problem: Glioblastoma cells often inactivate DNA repair pathways or find ways to bypass apoptosis, allowing mutated cells to survive and continue growing despite TMZ treatment. Key Insight: The failure of TMZ isn’t due to a lack of initial DNA damage but rather the cancer cells’ ability to sidestep the consequences of this damage through complex repair pathways. Key Discoveries from the Study: 1. Resistance Mechanisms Identified: • Researchers discovered specific DNA repair pathways that glioblastoma cells exploit to avoid TMZ-induced cell death. • These pathways enable the repair or tolerance of DNA mutations, allowing cancer cells to survive and resist therapy. 2. Bioinformatics Integration: • Advanced bioinformatics analysis revealed genetic and molecular signatures associated with TMZ resistance. • Identifying these patterns allows scientists to predict which tumors are likely to resist treatment and why. 3. Potential Therapeutic Targets: • Researchers pinpointed key proteins and pathways that could serve as targets to disrupt the repair mechanisms and restore TMZ sensitivity in resistant cells. The Takeaway: This groundbreaking research provides critical insights into how glioblastoma cells resist temozolomide treatment, shedding light on DNA repair mechanisms and potential therapeutic targets. By disrupting these resistance pathways, scientists hope to enhance the effectiveness of TMZ, improve survival rates, and bring us closer to a personalized approach to glioblastoma treatment. While challenges remain, these findings represent a promising step forward in the fight against one of the most aggressive forms of brain cancer.

🔥When Cancer Outsmarts Treatment, Science Must Outthink Cancer🔥 A recent Science Advances paper caught my attention, not just as a physician, but as someone who has spent decades watching cancer evolve faster than our therapies. The study reveals a critical mechanism in EGFR-mutant non-small cell lung cancer (NSCLC): 🧬 cancer cells don’t just mutate to resist drugs , they actively protect those mutations. 🔬 The key insight: Mutant EGFR proteins are stabilised by a newly identified P2Y2–integrin axis, driven by high extracellular ATP. This “protective shield” prevents EGFR degradation, allowing cancer cells to survive and thrive despite EGFR-TKI therapy. In simple terms: 👉 The cancer cell builds a biochemical bunker around its most dangerous mutation. ⚛️ What’s compelling is that when researchers disrupted this axis via P2Y2, FAK, or ATP-related pathways, especially in combination with TKIs , drug resistance weakened and tumour growth slowed. 👨⚕️ My perspective as a doctor: For years, we’ve focused almost exclusively on blocking the signal. This research reminds us that stability, trafficking, and cellular context matter just as much. 💎 Cancer is not static. It adapts, shields itself, and rewires survival pathways. ⚛️ Future oncology will not be: • One drug • One target • One pathway 👉 It will be systems-based, combination-driven, and biology-respecting. This is how we move from: ❌ chasing resistance ➡️ anticipating it And ultimately, this is how precision medicine becomes truly precise. 👉 Science like this gives hope not hype for patients facing resistant disease. Aspire. Inspire. Achieve.

Drug resistance is a principal limitation to the long-term efficacy of cancer therapies. Cancer genome sequencing can retrospectively delineate the genetic basis of drug resistance, but this requires large numbers of post-treatment samples to nominate causal variants. Here we prospectively identify genetic mechanisms of resistance to ten oncology drugs from CRISPR base editing mutagenesis screens in four cancer cell lines using a guide RNA library predicted to install 32,476 variants in 11 cancer genes. We identify four functional classes of protein variants modulating drug sensitivity and use single-cell transcriptomics to reveal how these variants operate through distinct mechanisms, including eliciting a drug-addicted cell state. We identify variants that can be targeted with alternative inhibitors to overcome resistance and functionally validate an epidermal growth factor receptor (EGFR) variant that sensitizes lung cancer cells to EGFR inhibitors. Our variant-to-function map has implications for patient stratification, therapy combinations and drug scheduling in cancer treatment. The text above is from the author's abstract, the full paper can be found here: https://lnkd.in/dTxWsMDN

Colorectal cancer (CRC) is not a genetic disease with a microbial bystander problem. It's a microbial ecosystem disease with a genetic consequence. This recent review (https://lnkd.in/eM_2EJS6)  reframes CRC pathogenesis entirely, not as the accumulation of somatic mutations in an otherwise passive gut, but as the coordinated output of polymicrobial consortia reprogramming immune, metabolic, neural, and endocrine networks simultaneously. The mechanistic case is now hard to dismiss: First, bacterial genotoxins leave traceable mutational signatures in human cancer genomes. Colibactin from pks⁺ E. coli generates defined SBS-pks and ID-pks patterns, reproduced in human intestinal organoids. Chronic colibactin exposure then selects for homologous recombination-proficient clones, conferring resistance to irinotecan. The same bacterium that initiates the tumor shapes its therapeutic trajectory. Second, the immunosuppressive TME in CRC is largely microbiome-constructed. F. nucleatum engages TIGIT to suppress NK cell cytotoxicity; ETBF drives IL-17–STAT3–NF-κB cascades recruiting MO-MDSCs to tumor-prone colonic regions; dysbiotic metabolite shifts, reduced butyrate, accumulated lactate, kynurenine IDO1 induction, collectively produce a TME of functional immune paralysis. Effector T cells are present but metabolically and spatially neutralized. Third, the neural axis is not peripheral. Increased intratumoral nerve density in CRC correlates with invasion and perineural spread. F. nucleatum and B. fragilis stimulate pro-neurogenic cytokines IL-6 and CXCL12, feeding the neuro-microbial loop. Enteric glial cells, previously considered structural, now emerge as microbiome-responsive immunomodulatory hubs driving myofibroblast proliferation and metastatic niche preparation. The AHA moment from this review: these axes don't operate sequentially. They are simultaneously active, mutually reinforcing, and collectively resistant to single-pathway intervention. Biofilm-structured consortia, F. nucleatum, ETBF, pks⁺ E. coli in coordinated spatial organization, create hypoxic, inflammation-sustaining niches that evolve alongside tumor progression, adapting to oxygen gradients and immune pressure in real time. The therapeutic implications are substantial. FMT from immunotherapy responders has restored PD-1 sensitivity in preclinical CRC models. Phage VA7 targeting B. fragilis reverses 5-FU chemoresistance. Engineered E. coli Nissle 1917 constructs carrying hypoxia-responsive biosensors deliver cytotoxic payloads directly into the TME. These are not future directions, several are in clinical phase evaluation now. #Oncology #ColorectalCancer #GutMicrobiome #TumorMicroenvironment #Immunotherapy #Microbiome #CancerResearch #PrecisionMedicine

I am excited to share the most recent publication from my group's efforts in understanding and revealing molecular determinants of chemoresistance in Ovarian Cancer. In this article, spearheaded by a super-talented graduate student, Harun Ozturk, we show that PRMT5, a protein encoded by a protein arginine methyl transferase gene, is highly upregulated during chemoresistance. More critically, Harun Ozturk's unbiased CRISPR screening identified that this upregulation is due to the inhibition of KEAP1 during chemotreatment. These findings not only reveal a novel mechanism of chemoresistance but also bring us closer to beating this significant clinical challenge because there are several available PRMT5 inhibitors. Our in vitro and in vivo findings show that these inhibitors may create a synthetic lethality in chemoresistance cells when combined with first-line chemo in high-grade serous ovarian cancer (HGSOC). I also want to thank all the other lab members and Sandra Orsulic for our productive collaboration. Here is a link to the full article: https://lnkd.in/gq4H5nwi Northwestern University ROBERT H. LURIE COMPREHENSIVE CANCER CENTER OF NORTHWESTERN UNIVERSITY

Blocking vitamin B7 shown to completely shut down treatment-resistant tumors. Oncologists have long known that many aggressive tumors exhibit an extreme "glutamine addiction," depending heavily on this specific amino acid to power their rapid cellular replication. However, when therapeutic interventions cut off this vital nutrient supply, resilient cancer cells routinely survive by activating an emergency metabolic bypass that utilizes a mitochondrial enzyme called pyruvate carboxylase. An international research team at the University of Lausanne has discovered that this structural backup system has a fatal vulnerability: it relies completely on biotin—commonly known as vitamin B7—to function. By running a comprehensive functional nutrient-genetic profile, scientists demonstrated that restricting the availability of biotin completely paralyzes this enzyme, trapping the cancer cells in an inescapable state of nutrient starvation that halts tumor growth. This metabolic trap proved exceptionally lethal in tumors harboring mutations in the FBXW7 gene, a common genetic alteration linked to chemotherapy resistance across a broad spectrum of human cancers. While this molecular discovery provides a powerful new blueprint for targeted oncology, public health experts emphasize that these preclinical findings are confined to controlled laboratory models and do not mean individuals should eliminate vitamin B7 from their daily diet. Biotin remains a fundamental cofactor for healthy systemic metabolism, nervous system function, and cellular gene regulation in normal human tissues. Instead, the true clinical value of the research lies in the development of highly specific, localized pharmacological agents designed to temporarily inhibit biotin-dependent enzymes directly within the tumor microenvironment.

Tumor-Derived Exosomes Tumor-derived exosomes (TDEs) are small extracellular vesicles released by cancer cells that play a crucial role in tumor growth, metastasis, immune evasion, and drug resistance. These exosomes carry a variety of bioactive molecules, including proteins, lipids, RNA, and DNA, which they deliver to other cells within the tumor microenvironment and even to distant organs, exerting a profound impact on cancer progression. One of the key functions of TDEs is to reshape the tumor microenvironment to favor cancer cell survival and proliferation. For example, TDEs carry oncogenic factors that promote angiogenesis (the formation of new blood vessels), allowing tumors to obtain more nutrients and oxygen. In addition, they transfer matrix metalloproteinases (MMPs), which degrade the extracellular matrix and promote cancer invasion and metastasis to other tissues. Tumor-derived exosomes also play an important role in immune evasion. They can suppress the activity of immune cells, such as T cells, natural killer (NK) cells, and dendritic cells, allowing cancer cells to evade immune detection and destruction. By carrying immunosuppressive molecules such as PD-L1 and TGF-β, TDEs help create an immunosuppressive microenvironment that protects tumors from immune attack. In addition, TDEs are associated with drug resistance, a major challenge in cancer treatment. They can transfer drug resistance molecules, such as specific microRNAs and proteins, to nearby cancer cells, making them less responsive to chemotherapy or targeted therapies. The exchange of drug resistance signatures between cancer cells through exosomes complicates treatment efforts and often leads to relapse. In summary, tumor-derived exosomes are important players in cancer progression. Their roles in reshaping the tumor microenvironment, promoting metastasis, enabling immune evasion, and promoting drug resistance make them promising targets for therapeutic intervention and potential biomarkers for early cancer diagnosis. References [1] Cong Lyu et al., Cell Death & Disease 2024 (https://lnkd.in/edhi3S5X) [2] Shiqian Chen et al., Chin J Cancer Res 2024 (10.21147/j.issn.1000-9604.2024.02.05) [3] Ladan Mashouri et al., Molecular Cancer 2019 (https://lnkd.in/dk72eUr8) #TumorExosomes #CancerResearch #TumorMicroenvironment #Metastasis #ImmuneEvasion #DrugResistance #ExosomeTherapy #Oncology #CancerTreatment #BiomedicalResearch #Exosomes #Newsletter #CancerBiomarkers #Biotech

🔬 CRISPR, NIR-II light, and the battle against cisplatin resistance in laryngeal cancer Cisplatin remains a cornerstone in treating laryngeal cancer, yet nearly half of patients eventually develop resistance, leading to recurrence and poor outcomes. A new study in npj Precision Oncology sheds light on a promising way forward: targeting TNFAIP2 with a light-controlled CRISPR-Cas9 nanosystem. Key findings: 🧬 TNFAIP2 identified as a resistance driver: High expression correlates with cisplatin resistance, tumor invasion, and poor survival. 🌐 Mechanism uncovered: TNFAIP2 activates the NRF2 pathway, enhancing oxidative stress defenses and epithelial–mesenchymal transition (EMT), both hallmarks of chemoresistance. 💡 Innovative solution: Researchers engineered a red blood cell–coated CRISPR-Cas9 nanosystem activated by second near-infrared (NIR-II) light. This allowed precise, non-invasive knockout of TNFAIP2 in resistant cells. 📉 Impact: TNFAIP2 knockout lowered the cisplatin IC50 from 12.55 → 4.37 µg/mL, reduced migration/invasion, elevated ROS, and triggered apoptosis. 🐭 In vivo validation: In mouse xenografts and PDX models, combining cisplatin with the NIR-II CRISPR nanosystem significantly suppressed tumor growth. 👉 Why it matters: This approach integrates gene editing, nanotechnology, and photothermal control to precisely re-sensitize tumors to chemotherapy—without systemic toxicity. While still preclinical, it represents a new paradigm in overcoming drug resistance in solid tumors. As medical innovation accelerates, the question becomes: Can light-controlled gene editing platforms like this be scaled safely for patients in the clinic? #CancerResearch #CRISPR #Oncology #Nanomedicine #MedicalWriting Figure and Paper: 📎 Li, X., Wang, J., Guo, J. et al. Targeting TNFAIP2 with NIR-II CRISPR-Cas9 nanosystem to overcome cisplatin resistance in laryngeal cancer. npj Precis. Onc. 9, 263 (2025). https://lnkd.in/eGerCvAS

Drug‑resistant cancer is usually described as “complex” and “multi‑factorial”, which is another way of saying “we don’t really know how it works.” Something needs to be said when a study actually does turn that complexity into a crisp mechanism. The new NSMB work on promoter reinforcement does exactly that: it shows that, under TEAD inhibition, mesothelioma cells don’t just rewire a few pathways, they rewire where regulation lives. Distal enhancers lose functional load; promoters, wired by a KLF4‑centric transcription factor network, become the primary survival engine. In other words, resistance here is not “new signalling,” it’s a hard switch from enhancer‑centric to promoter‑centric control under drug pressure, with promoter‑bound factors emerging as actionable vulnerabilities. For anyone working on targeted therapies, epigenetic drugs, or AI‑driven multi‑omics, this is the kind of mechanism‑level insight that turns “big data” into a precise, testable strategy: to kill resistant cells, you may need to stop treating promoters as bystanders and start treating them as the main target.