Autophagy occupies a paradoxical place in cancer biology. In established tumours, the self-digestion pathway often helps malignant cells survive chemotherapy, starvation and other stresses by breaking down damaged components and recycling their building blocks. Many cancers guard this survival mechanism jealously. The new work flips that logic: when PAX9 is present in oral cancer cells, it drives autophagy so hard and so persistently that the process crosses a threshold from protective to destructive, a phenomenon researchers call lethal autophagy.

The mechanism at the heart of this effect is transcriptional. PAX9 is a DNA-binding protein, and the team found that its ability to kill cancer cells depends entirely on that function. When the researchers introduced the wild-type gene into oral cancer cells, expression of autophagy-related genes rose, lysosomal function intensified, and autophagic flux — the complete flow of cellular cargo through autophagosomes and into lysosomes for degradation — accelerated markedly. The cells responded by forming fewer orospheres, structures that reflect tumour-initiating capacity, and by undergoing apoptosis.

To prove the transcription factor’s role directly, the team engineered two point mutations in the PAX9 protein, L27P and I29T, which sit in the paired DNA-binding domain. Both mutations blocked the autophagy response and restored cell viability, showing that without PAX9’s ability to engage its target genes, the lethal cascade never begins. The result is technically elegant: it separates PAX9’s transcriptional activity from any indirect protein-level effects and establishes the gene’s antitumour action as strictly transcription-dependent.

The most consequential discovery, however, concerns what PAX9-driven autophagy chooses to digest. The researchers found that epidermal growth factor receptor, EGFR, is degraded through the autophagy-lysosome route in PAX9-expressing cells. EGFR is one of the most important growth drivers in head and neck cancer; amplification of its gene copy number is linked to poor prognosis, and EGFR-targeting drugs are standard components of oral cancer therapy. By funneling EGFR into the lysosomal shredder, PAX9 simultaneously strips cancer cells of a central survival signal and primes them for death.

This finding carries immediate therapeutic weight. Restoring PAX9 activity in tumours could, in principle, remove EGFR from the cancer cell’s toolkit through an entirely different route than antibody or small-molecule blockade, and the study showed that PAX9 expression sensitised cells to cisplatin, a mainstay chemotherapy drug. In a xenograft model in nude mice, PAX9 overexpression inhibited tumour growth and enhanced cisplatin sensitivity, providing in vivo support for the idea that this developmental gene could complement existing treatments rather than replace them.

The clinical corollary is equally telling. When the team examined human oral cancer tissue samples, PAX9 expression dropped as tumour grade increased, and the same decline appeared in a DMBA-induced hamster model of oral carcinogenesis. In vitro, exposure to carcinogens reduced PAX9 levels while raising DNMT1, the enzyme responsible for maintaining DNA methylation patterns. That pattern suggests the gene is silenced epigenetically during malignant transformation, a hypothesis consistent with the group’s earlier work showing that reactivating PAX9 by inhibiting DNA methyltransferases triggers antitumour effects in oral squamous cell carcinoma. Related PAX family members, including PAX1 and PAX4, have also been linked to tumour suppression and methylation-based silencing in other cancers, hinting at a broader family-level theme.

The study also contributes to a growing literature on the transcriptional regulation of autophagy. Classic regulators such as TFEB, which links lysosomal biogenesis to autophagy, and FOXO factors have dominated that field; PAX9 now joins a select group of transcription factors capable of dialling autophagy into the lethal range. Earlier work on dendrogenin A and other ligand-dependent transcriptional inducers of lethal autophagy suggested the concept had therapeutic potential, but identifying a specific developmental transcription factor that naturally performs this function in oral tissue gives the idea a concrete molecular handle.

Translating these findings into the clinic will require overcoming the challenge of reactivating a silenced gene in tumour cells. DNA methyltransferase inhibitors already exist and are approved for haematological malignancies, and the current results suggest they could one day be paired with autophagy or EGFR-targeting strategies in oral cancer. Because PAX9 loss appears to track with tumour grade, the protein may also serve as a biomarker indicating which patients would benefit from therapies designed to restore or mimic its function.

For a gene whose canonical job is to build the palate and pattern the dentition of the developing embryo, PAX9’s second career as an executioner of oral cancer cells is a vivid reminder that developmental biology and oncology share far more machinery than is often appreciated. The authors note that funding came from the Indian Council of Medical Research, the National Key R&D Program of China, Guangdong and Shenzhen science programs, Tsinghua Shenzhen International Graduate School and the US National Institutes of Health, underscoring the international scope of the effort. If the transcriptional circuit the team mapped can be pharmacologically engaged in patients, the humble tooth-development gene may prove to be one of oral cancer’s most surprising vulnerabilities.

Subject of Research: PAX9-mediated lethal autophagy and EGFR degradation as a tumour-suppressive mechanism in oral squamous cell carcinoma

Article Title: PAX9 activates autophagy through a transcription-dependent mechanism, promoting EGFR degradation to restrict cell survival in oral cancer

Article References: Bhol, C. S., Kar, R. K., Mishra, S. R., Mishra, P., Mahapatra, K. K., Zhang, X., Patra, S. K., Patil, S., Sethi, G., Klionsky, D. J., Lobie, P. E., Pandey, V., & Bhutia, S. K. (2026). PAX9 activates autophagy through a transcription-dependent mechanism, promoting EGFR degradation to restrict cell survival in oral cancer. British Journal of Cancer. https://doi.org/10.1038/s41416-026-03608-6

Image Credits: AI Generated

DOI: 10.1038/s41416-026-03608-6

Keywords: PAX9, oral cancer, autophagy, EGFR, lethal autophagy, tumour suppressor, transcription factor, lysosome, cisplatin, chemosensitisation, oral squamous cell carcinoma, DNA methylation

One of the most pressing challenges in oncology is the resistance that develops against therapies directed at mutated RAS proteins, which drive roughly one-third of human cancers. MSK scientists employed state-of-the-art X-ray crystallography alongside analyses of clinical specimens from patients treated with the tri-complex inhibitor daraxonrasib. This drug operates by forming a ternary complex among RAS, the molecular glue, and the effector protein cyclophilin A (CYPA), blocking oncogenic signaling. Their research uncovered three distinct resistance mechanisms: secondary mutations in RAS diminishing drug affinity; mutations in the BRAF gene promoting RAF protein dimerization that obstructs inhibitor binding; and CYPA mutations compromising complex formation, primarily observed in laboratory settings. Defining these mechanisms not only elucidates how tumors bypass therapy but also guides the design of combination treatments that could preempt or counteract resistance, thereby broadening the impact of tri-complex inhibitors far beyond daraxonrasib itself.

Another pivotal advance arises in tackling the heterogeneity within tumors, particularly diffuse midline glioma (DMG), a lethal pediatric brain cancer notorious for its cellular diversity and therapeutic refractoriness. A collaborative effort between MSK and Columbia University deployed a computational framework that integrates single-cell transcriptomics with protein regulatory network analyses. They identified seven conserved, coexisting tumor cell states, each governed by distinct master regulator proteins. By systematically evaluating 372 cancer drugs, the team predicted compounds capable of inactivating these regulators. Subsequent in vivo validation in murine models demonstrated that while single-agent therapies targeting minor cell populations had limited efficacy, rationally designed drug combinations effectively suppressed all malignant states. Notably, combinations such as avapritinib with ruxolitinib and avapritinib with larotrectinib led to significant survival benefits, underscoring the power of systems biology to translate tumor complexity into actionable therapeutic regimens.

The study of pancreatic cancer, a malignancy often detected too late for curative intervention, also benefited from MSK’s innovation in organoid technology. By differentiating human pluripotent stem cells into pancreatic progenitors and introducing oncogenic alterations—including KRAS activation alongside CDKN2A, TP53, and SMAD4 deletions—researchers successfully recreated early tumorigenic states in three-dimensional cultures. This human-derived model revealed critical differences from established murine models by demonstrating the necessity for multiple concurrent mutations to initiate tumorigenesis. Crucially, the researchers identified suppression of TET1, a DNA demethylase important for cellular homeostasis, as a key epigenetic alteration promoting cancer progression. Restoration of TET1 function emerges as a promising preventive strategy, offering insights into early molecular events preceding overt pancreatic cancer and highlighting the potential of epigenetic interventions.

Expanding into rare cancers, MSK scientists developed the first biobank of patient-derived organoids for appendiceal cancer, a disease marked by aggressive peritoneal dissemination and limited treatment options. The team isolated primary and metastatic tumor cells, growing them into 3D organoids that faithfully recapitulate tumor heterogeneity and progression. Comparative genomic analysis revealed mutations driving cancer-specific pathways and underscored increased chemoresistance in metastatic lesions. Importantly, pharmacological targeting of the RAS and WNT pathways yielded potent antitumor activity in lab models, presenting new therapeutic candidates for clinical translation. This resource represents a critical platform for the study of appendiceal cancer biology and tailored drug discovery in a malignancy that has historically lagged in research investment.

In the realm of cancer metabolism, MSK researchers tackled the challenge of developing selective covalent inhibitors that irreversibly bind target proteins without off-target toxicity. By pioneering a novel ‘scavenging proteomics’ approach that detects residual unbound proteins, the team achieved unprecedented accuracy in characterizing molecular interactions inside cells. Applying this methodology, they designed CNP7, a small molecule that covalently inhibits HMGCS1, the first committed enzyme in the mevalonate pathway essential for cholesterol synthesis and cell growth. Unlike statins, which reversibly inhibit downstream enzymes such as HMGCR and exhibit declining efficacy, CNP7 locks HMGCS1’s catalytic cysteine, producing durable pathway suppression. Cryo-electron microscopy crystallized the atomic details of this interaction, while diverse cancer cell lines demonstrated differential sensitivity, suggesting that direct HMGCS1 targeting could refine metabolic intervention strategies with enhanced efficacy and specificity.

Collectively, these studies underscore a multi-faceted assault on cancer by combining detailed mechanistic insight, computational prowess, and biological model innovation. From unraveling resistance to RAS inhibitors, decoding tumor heterogeneity in pediatric brain cancers, modeling early pancreatic tumorigenesis, to innovating organoid resources for rare appendiceal tumors, MSK researchers are catalyzing a new era in precision oncology. The molecular tool developed for metabolic inhibition not only advances therapeutic design but also sets new standards in verifying drug target engagement at the cellular level. These insights carve a promising path towards more durable and individualized treatments for cancers that have long posed formidable challenges.

By elucidating the complex interplay between genetic mutations, protein interactions, and metabolic dependencies across diverse tumor types, MSK’s integrated approach holds transformative potential for improving patient outcomes. These cutting-edge discoveries embody the power of convergence science, combining structural biology, computational analysis, and patient-derived models to dismantle cancer’s defense mechanisms. The emergence of such comprehensive strategies signifies a paradigm shift that may soon translate into clinical breakthroughs for some of the most intractable malignancies.

As researchers continue to expand upon these findings, the implications resonate universally within the cancer research community. The frameworks developed for overcoming resistance, co-targeting heterogeneous tumor cell populations, and dissecting metabolic vulnerabilities can be adapted broadly across cancer types. Through sustained interdisciplinary efforts, these advances herald a new chapter in designing smarter, more effective cancer therapies that anticipate and circumvent tumor adaptability, ultimately improving survival and quality of life for patients worldwide.

Subject of Research: Mechanisms of resistance to RAS-targeted therapies, tumor heterogeneity in pediatric brain tumors, pancreatic cancer development, appendiceal cancer models, and targeting cancer metabolism.

Article Title: Advanced Multidisciplinary Approaches Illuminate Cancer Resistance and Reveal Novel Therapeutic Targets at Memorial Sloan Kettering Cancer Center.

News Publication Date: Not specified.

Web References:

• Cell: https://www.cell.com/cell/fulltext/S0092-8674(26)00332-6
• Nature Genetics: https://www.nature.com/articles/s41588-026-02550-w
• Developmental Cell (Pancreatic cancer): https://www.sciencedirect.com/science/article/pii/S1534580726001590
• Developmental Cell (Appendiceal cancer): https://www.cell.com/developmental-cell/fulltext/S1534-5807(26)00161-9
• Journal of the American Chemical Society: https://pubs.acs.org/doi/10.1021/jacs.6c02556

References: See above web references.

Image Credits: Memorial Sloan Kettering Cancer Center.

Keywords

RAS mutations, cancer resistance, molecular glue drugs, tumor heterogeneity, pediatric brain tumors, diffuse midline glioma, organoids, pancreatic cancer, appendiceal cancer, cancer metabolism, covalent inhibitors, mevalonate pathway, precision oncology, structural biology, computational modeling

Hepatocellular carcinoma remains a formidable clinical challenge, largely due to its late diagnosis and resistance to conventional therapies. Existing treatments, including surgical resection, locoregional therapies, and systemic agents, often fall short in delivering long-term survival benefits for many patients. The study’s focus on ChaC1, a known regulator of intracellular stress responses, capitalizes on the growing understanding that cancer cells rely heavily on proteostasis mechanisms to survive hostile tumor microenvironments. By targeting these delicate cellular processes, the research team aimed to disrupt the cancer’s adaptive capabilities, thereby inducing cell death selectively in malignant hepatocytes.

The researchers employed an innovative ChaC1-based screening platform, designed to identify compounds that modify the activity of this critical proteostasis effector. ChaC1 is implicated in regulating glutathione metabolism and redox balance, processes intricately linked to cellular oxidative stress management. Intriguingly, alterations in these pathways have been strongly associated with cancer cell survival and drug resistance. By leveraging this biochemical node as a screening target, the team succeeded in uncovering compounds that exerted augmented cytotoxic effects in HCC models.

Auranofin, a gold-containing compound with a long history of use in rheumatoid arthritis, emerged from the screens as a potent modulator of ChaC1 activity. Importantly, auranofin’s inhibition of thioredoxin reductase disrupts cellular antioxidant defenses, heightening oxidative stress—a vulnerability exploited by combining it with proteasome inhibitors. Proteasome inhibition is a therapeutic approach that hinders the degradation of misfolded or damaged proteins, leading to proteotoxic stress that cancer cells are particularly sensitive to. The synergistic effect of these two agents triggers an overwhelming accumulation of toxic protein aggregates and reactive oxygen species, compelling cancer cells towards apoptosis.

In vitro experiments conducted across various hepatocellular carcinoma cell lines demonstrated a dramatic reduction in cell viability when treated with the combined regimen of auranofin and proteasome inhibitors, compared to either agent alone. This finding underscores the therapeutic potential of capitalizing on dual vulnerabilities in the cellular protein quality control machinery. The study further delved into mechanistic analyses revealing that ChaC1 modulation aggravates oxidative and proteotoxic stress, effectively pushing tumor cells beyond their survival threshold.

Another intriguing aspect of the research pertains to the selective toxicity profile of the drug combination. While cancer cells exhibited pronounced susceptibility to the dual treatment, non-malignant hepatocytes were largely spared, suggesting a possible therapeutic window that could minimize collateral damage in normal tissue. This selectivity is paramount in cancer treatment development, where minimizing adverse effects remains a critical hurdle in clinical application.

The clinical implications of this discovery could be profound. Given that both auranofin and proteasome inhibitors such as bortezomib and carfilzomib are already FDA-approved agents, repurposing these drugs for HCC treatment could significantly shorten the timeline from bench to bedside. The use of clinically validated compounds also facilitates the design of combination therapy trials, as known pharmacokinetics and safety profiles can expedite regulatory approvals and patient enrollment.

Moreover, the identification of ChaC1 as a predictive biomarker for therapeutic responsiveness opens the door to more personalized medicine approaches in oncology. Patients with elevated ChaC1 expression or activity in their tumors might be stratified to receive this combinatorial treatment, enhancing efficacy and sparing non-responders from unnecessary toxicity. Future studies aimed at validating these biomarkers in clinical cohorts will be indispensable for translating the preclinical findings into routine clinical practice.

The research also raises exciting possibilities for investigating similar synergistic drug combinations in other cancers where proteostasis disruption is a hallmark, broadening the impact beyond hepatocellular carcinoma. Such cross-cancer applicability would underscore the universal importance of cellular stress response pathways in malignancy and cancer therapy.

From a molecular biology perspective, this study deepens our understanding of how redox regulation and protein degradation pathways converge to control cancer cell survival. It provides compelling evidence that targeting these interconnected cellular stress responses can deliver powerful anti-tumor effects. This aligns with emerging trends in oncology that emphasize combinational strategies over single-agent treatments for overcoming resistance and enhancing therapeutic durability.

In summary, Yu et al.’s work represents a significant advancement in the fight against hepatocellular carcinoma. By ingeniously leveraging ChaC1’s role in cellular stress response, they have uncovered a synergistic lethal interaction between auranofin and proteasome inhibitors. This discovery not only points to an innovative treatment strategy but also exemplifies the power of targeted, mechanism-based drug screening in oncology drug development. As follow-up in vivo studies and clinical trials advance, the oncology community awaits with anticipation the potential of these findings to improve outcomes for patients afflicted with this devastating disease.

This study’s multidisciplinary methodology, integrating molecular screening, pharmacology, and functional cell biology, serves as a paradigm for future drug discovery endeavors. The promising results encourage further exploration of proteostasis and oxidative stress networks as fertile ground for next-generation cancer therapies. With continuous advancements in biomarker-guided treatment and drug combination strategies, the dawn of more effective, less toxic cancer therapeutics appears within reach.

Given the urgent need to develop better therapies for hepatocellular carcinoma, the identification of this novel drug synergy brings hope to patients and clinicians alike. It also exemplifies the remarkable potential of repurposing existing drugs in innovative ways, a cost-effective and efficient path toward addressing unmet clinical needs. As our molecular toolkit and understanding of cancer complexities evolve, studies like this pave the pathway to transformative breakthroughs that could redefine clinical oncology in the near future.

Subject of Research: Hepatocellular carcinoma treatment and ChaC1-mediated cellular stress pathways.

Article Title: ChaC1-based drug screenings identify a synergistic lethal effect of auranofin and proteasome inhibitors in hepatocellular carcinoma cells.

Article References:
Yu, C., Liu, J., Jian, H. et al. ChaC1-based drug screenings identify a synergistic lethal effect of auranofin and proteasome inhibitors in hepatocellular carcinoma cells. Cell Death Discov. 11, 532 (2025). https://doi.org/10.1038/s41420-025-02838-6

Image Credits: AI Generated

DOI: 17 November 2025