The scope of the analysis is unusually broad. The authors surveyed molecular and cellular evidence from 101 multicellular species whose maximum lifespans reach at least 250 years, drawing on the AnAge database and a wide range of primary studies to compile lifespan records. Ninety of these species are plants, from oaks and pines to the ancient seagrass Posidonia oceanica and the creosote bush of the American desert, while eleven are animals, including hydras, sponges, tubeworms and the freshwater planarian Schmidtea mediterranea. Some of these organisms only modestly exceed the 250-year threshold, but others may persist for thousands or even tens of thousands of years. At the far edge of the spectrum, the planarian and the jellyfish Turritopsis dohrnii are considered potentially immortal, meaning that no intrinsic limit to their lifespan has been demonstrated under suitable conditions.

What makes the review methodologically interesting is the way it frames the comparison. Rather than asking only why some species live longer than others, the authors examined two distinct dimensions of longevity: variation between exceptionally long-lived species and shorter-lived ones, and variation among individuals within a single long-lived species. This distinction matters because the mechanisms that make one species outlast another across evolutionary time need not be the same mechanisms that determine why one 500-year-old pine survives its neighbor. The evidence base they assembled spans genetics, genomics, transcriptomics, proteomics and metabolomics, alongside studies of telomere maintenance, stress resistance, regeneration and tumor formation, giving a genuinely multi-layered picture of what extreme longevity looks like at the level of cells and molecules.

Several recurring themes emerged from this cross-species survey. Compared with shorter-lived relatives, extremely long-lived organisms tend to show better DNA maintenance and repair, greater resistance to both cellular and environmental stress, pronounced regenerative capacity, better preservation of stem-cell populations, and mechanisms that appear to suppress cancer development. Comparative genomic studies have additionally identified longevity-associated pathways involved in programmed cell death, protein homeostasis, resistance to oxidative stress and responses to environmental damage. None of these features is exotic in itself; each is a familiar component of cellular housekeeping. What is striking is that they recur together, in organisms as different as a conifer and a cnidarian, suggesting that evolution has converged on a similar toolkit whenever lifespan is pushed to extremes.

Regeneration stands out as particularly important in some of the most remarkable cases. Hydra can continuously replace the cells of its body, effectively renewing itself throughout life. Turritopsis dohrnii can reverse from a mature medusa back to an earlier developmental stage, restarting its life cycle and earning its popular name as the immortal jellyfish. Planarians carry a population of adult stem cells called neoblasts, which can generate many different cell types and support the regeneration of entire body parts, an ability that underlies their apparent exemption from aging. Long-lived plants show an analogous pattern in a botanical register: species such as Scots pine and Ginkgo biloba appear to preserve the pluripotency of their cells during aging better than shorter-lived plants do, maintaining the developmental flexibility needed to keep growing and replacing tissues across centuries.

Equally instructive is what the review does not find. The idea that a single familiar aging mechanism can explain exceptional longevity does not survive the evidence. Telomere length, telomerase activity, metabolic rate and antioxidant activity do not consistently account for lifespan differences among individuals within exceptionally long-lived species. Telomere characteristics vary not only between species but even between tissues within the same organism, which complicates any attempt to read lifespan directly from telomere biology. The authors conclude that extreme longevity arises from multiple interacting biological strategies rather than from a universal molecular switch, a conclusion that cautions against the popular habit of reducing aging to any one measurable marker.

Cancer resistance may be another essential component of the picture. Long lifespans combined with extensive cell renewal should, in principle, multiply the opportunities for malignant transformation, yet tumors appear relatively uncommon in several exceptionally long-lived species. Planarians offer a vivid example: they combine extraordinary regenerative output with robust DNA-repair mechanisms and conserved regulators of cell division, apparently keeping proliferation under control even as tissues are continuously rebuilt. The authors suggest that the anticancer adaptations of long-lived organisms deserve systematic investigation, while being careful to note that the available evidence remains incomplete. Large animals such as elephants and whales have famously evolved extra copies of tumor-suppressor genes, and the new review extends that logic to the plant and invertebrate champions of longevity, where the relevant mechanisms are far less well characterized.

Perhaps the most conceptually significant finding is the convergence between the two dimensions of longevity the authors set out to compare. Mechanisms associated with lifespan variation within species overlap with those that distinguish longer-lived species from shorter-lived ones, and both categories point toward DNA maintenance, stemness and stress-resistance pathways. Notably, these are also the hallmark features of early developmental stages and of germ cells, the two contexts in which biology most conspicuously refuses to age. The authors compress this pattern into a memorable formulation: living young appears to be a strategy of living long. In other words, the longest-lived organisms seem to maintain, into adulthood and old age, a molecular state that most cells abandon during differentiation, keeping their tissues in something closer to an embryonic or germline configuration.

The review also insists that longevity cannot be understood apart from the environment. Temperature, ecological pressures and other external conditions interact with molecular pathways over evolutionary timescales, and these relationships differ substantially among species. A cold, stable deep-sea environment slows metabolism and damage accumulation for an Antarctic sponge, while a desert shrub survives through drought tolerance and clonal growth, so no single environmental condition can be generalized as longevity-promoting. This ecological framing matters for interpretation as well: laboratory conditions rarely reproduce the circumstances under which extreme lifespans evolved, and measurements taken in cultivation or captivity may not reflect what happens in the wild.

For readers hoping that ancient trees and immortal jellyfish will yield a prescription for human life extension, the authors are appropriately restrained. The review does not establish that the longevity mechanisms of these species can be directly transferred to humans. What these organisms provide instead is a set of comparative biological models for identifying pathways that warrant further mechanistic and translational investigation, particularly those linking genome maintenance, stem-cell preservation and stress resistance to healthy aging. Major knowledge gaps remain, and the authors are candid about them: many exceptionally long-lived species have received little molecular study, existing investigations use different methods and tissues, and the field lacks comprehensive cross-species healthspan data comparable to existing lifespan databases. Larger studies using standardized methods and incorporating environmental information will be needed to separate causal longevity mechanisms from mere correlations. Even so, the central message is clear and quietly provocative. Living for centuries does not depend on a single gene or pathway, but on overlapping strategies for keeping DNA intact, preserving regenerative capacity and stemness, resisting stress and limiting cancer. Understanding how those strategies operate across the tree of life may not make humans immortal, but it could redefine what healthy aging means for a species that currently measures its ambitions in decades rather than millennia.

Subject of Research: Comparative biology of exceptional longevity across long-lived plant and animal species

Article Title: Exceptional longevity across species linked to DNA maintenance, stemness and stress resistance

Article References: Exceptional longevity across species linked to DNA maintenance, stemness and stress resistance. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: longevity, aging, DNA repair, stem cells, stress resistance, regeneration, telomeres, cancer resistance, comparative genomics, planarians, Hydra, healthspan

The molecule in question is PD-1, or programmed cell death protein 1, a receptor best known as the target of the blockbuster class of cancer immunotherapies called immune checkpoint inhibitors. PD-1 normally acts as a molecular brake on immune responses, and tumors exploit this brake by co-opting the PD-1/PD-L1 axis to paralyze cytotoxic T lymphocytes, the immune system’s primary tumor-killing cells. What makes the new findings so provocative is that the researchers found radiotherapy itself, a treatment intended to unleash anti-tumor immunity, drives PD-1 expression onto tumor-associated monocytes, converting these cells into immunosuppressive agents that undermine the very immune attack radiation is supposed to provoke.

Monocytes are circulating white blood cells that can be recruited into tissues, including tumors, where they differentiate into macrophages and related myeloid cells. Within the tumor microenvironment, these myeloid cells often take on a suppressive phenotype, dampening T cell activity and fostering an immunologically cold milieu that resists both immunotherapy and other treatments. The new study demonstrates that after radiotherapy, a distinct subset of tumor-associated monocytes upregulates PD-1, and that these PD-1-positive monocytes actively suppress the anti-tumor activity of CD8-positive T cells, the cytotoxic lymphocytes responsible for recognizing and destroying cancer cells.

Perhaps the most technically significant contribution of the work is the delineation of the signaling pathway that connects radiation to PD-1 induction on monocytes. According to the researchers, radiotherapy triggers the adenosine-A2AR-cAMP-PKA-NF-κB axis. In this cascade, adenosine, a purine nucleoside that accumulates in stressed and damaged tissues, engages the A2A adenosine receptor (A2AR) on the monocyte surface. Receptor activation raises intracellular cyclic AMP (cAMP), which in turn activates protein kinase A (PKA), ultimately engaging the transcription factor NF-κB to drive PD-1 expression. This pathway is a classic example of how tissue damage signals can be hijacked by tumors: adenosine is abundant in the hypoxic, metabolically stressed environment of irradiated tumors, and the study shows that this damage-associated molecule becomes the trigger for an immunosuppressive monocyte program.

The functional consequences of this conversion are substantial. When PD-1-positive monocytes accumulate after radiation, they suppress the activity of CD8-positive T cells, blunting the immune-mediated tumor killing that radiation therapy is known to promote through mechanisms such as immunogenic cell death and antigen release. In other words, radiation delivers a double-edged signal: it damages tumor cells in ways that should alert the immune system, but it simultaneously generates a myeloid cell population that mutes that alert. This may help explain a long-standing puzzle in radiation oncology, namely why the much-discussed abscopal effect, in which localized radiation provokes systemic tumor regression, occurs so rarely in clinical practice.

Critically, the researchers did not stop at mechanistic description. They showed that targeting this PD-1-positive monocyte subset enhanced the efficacy of radiotherapy in their experimental models, suggesting that depleting or inhibiting these cells could convert a partially resistant tumor into one that responds robustly to radiation. This therapeutic implication is significant because it points toward combination strategies: rather than simply escalating radiation doses, which risks toxicity, clinicians could in principle pair standard radiotherapy with agents that prevent monocyte PD-1 induction or eliminate the suppressive subset altogether.

The clinical relevance of the findings received direct support from human tissue analysis. The team examined tissues from patients whose tumors had proven resistant to radiotherapy and found elevated infiltration of PD-1-positive monocytes compared with what would be expected in a responsive setting. This correlation between the presence of the suppressive monocyte subset and treatment failure in patients elevates the work beyond a laboratory observation and suggests that the pathway identified in preclinical models operates in human disease. If validated in larger cohorts, PD-1-positive monocyte infiltration could serve as a biomarker predicting which patients are likely to resist radiotherapy and therefore need combination treatment from the outset.

The study also reframes the ongoing conversation about PD-1 as a therapeutic target. Checkpoint inhibitors such as anti-PD-1 and anti-PD-L1 antibodies were developed to release the brake on T cells, and they have transformed outcomes in melanoma, lung cancer and many other malignancies. But the new findings indicate that PD-1 biology extends beyond T cells: myeloid cells expressing PD-1 after radiation represent a separate, radiation-induced reservoir of immunosuppression. This raises intriguing questions about whether PD-1-targeting drugs exert some of their effects through monocytes rather than exclusively through T cells, and whether patients receiving radiotherapy might benefit from checkpoint blockade precisely because it neutralizes the radiation-induced monocyte program.

From a broader perspective, the work exemplifies a growing appreciation that the success or failure of cancer treatment is decided not only by the intrinsic sensitivity of tumor cells but by the ecosystem surrounding them. The tumor microenvironment is a dense network of immune, stromal and vascular components that respond dynamically to therapy. Radiation-induced cell death releases damage-associated molecular patterns, including adenosine, and the new study shows how one such signal is translated, through a defined receptor-second messenger-transcription factor cascade, into a durable immunosuppressive state. Understanding these feedback loops at the molecular level is essential if combination therapies are to be designed rationally rather than empirically.

For patients and clinicians, the immediate takeaway is one of cautious optimism. The identification of the adenosine-A2AR-cAMP-PKA-NF-κB pathway and the suppressive PD-1-positive monocyte subset it generates offers multiple potential points of intervention, from adenosine receptor antagonists to strategies that deplete the monocyte subset, and the demonstration that targeting these cells boosts radiotherapy efficacy provides a proof of principle. Translating that principle into the clinic will require further validation, safety assessment and well-designed trials, but the study supplies a clear mechanistic target for overcoming one of radiotherapy’s most persistent limitations. As the authors conclude, depleting this distinct immunosuppressive monocyte subset that accumulates after radiation represents a promising strategy to overcome resistance and strengthen anti-tumor immunity, a conclusion that could reshape how radiation oncology and immunotherapy are combined in the years ahead.

Subject of Research: Radiotherapy-induced PD-1 expression on tumor-associated monocytes and its role in immunosuppression and radioresistance

Article Title: Radiotherapy drives PD-1 expression on monocytes to attenuate anti-tumor immunity

Article References: Zhang, J., Chen, C., Mu, Q., Hou, Y., & Zhang, X. (2026). Radiotherapy drives PD-1 expression on monocytes to attenuate anti-tumor immunity. Cancer Immunology, Immunotherapy. https://doi.org/10.1007/s00262-026-04519-4

Image Credits: AI Generated

DOI: 10.1007/s00262-026-04519-4

Keywords: radiotherapy, PD-1, monocytes, tumor microenvironment, radioresistance, CD8-positive T cells, adenosine, A2A receptor, NF-kB, immunotherapy, cancer resistance, myeloid cells

Decitabine, an established chemotherapy used for bone marrow disorders and acute myeloid leukemia, works by incorporating into the genome and triggering cell death. However, the researchers explain that DCTPP1 recognizes chemically modified pieces of DNA generated during this process and degrades them, reducing decitabine’s anticancer potency. In prostate cancer cells, where drug responses can become weaker, this degradation may contribute to incomplete therapeutic effects.

To identify ways to disable DCTPP1, the team began with structural biology and chemical screening. They screened 10,000 compounds to find candidates that inhibit DCTPP1 activity. Three distinct chemical classes emerged, suggesting that the protein can be blocked through specific binding interactions.

The researchers then used X-ray crystallography to determine atomic-resolution structures of DCTPP1 bound to these inhibitors. This approach revealed that each inhibitor class occupies a particular nucleotide-binding pocket. With binding modes clarified at the atomic level, the team combined the DCTPP1 inhibitors with decitabine in living prostate cancer cell cultures.

Their experiments indicate that adding DCTPP1 inhibitors boosts decitabine’s effectiveness at killing prostate cancer cells. The findings support the idea that stopping DCTPP1 prevents degradation of decitabine-related DNA modifications, allowing the chemotherapy’s genome-integrating mechanism to proceed more fully.

The study was published June 15 in Proceedings of the National Academy of Sciences as part of NIH-funded research. The authors emphasize that future work will test whether these inhibitor scaffolds can be optimized to further increase potency and potentially extend benefits to additional cancer types beyond prostate cancer.

For patients facing castration-resistant prostate cancer, a form that can metastasize and has a low five-year survival rate, improved drug combinations could be clinically valuable. By repurposing and enhancing an existing therapy rather than developing entirely new drugs, the approach offers a strategic path toward more durable responses.

Funding included support from the National Cancer Institute and additional foundations, reflecting the multi-institutional effort behind the program.

Subject of Research: DCTPP1 protein inhibition to enhance decitabine activity in prostate cancer
Article Title: Newly Identified Inhibitors May Boost Chemotherapy Drug’s Ability to Fight Treatment-Resistant Cancers
News Publication Date: June 15
Web References: https://www.pnas.org/doi/full/10.1073/pnas.2534029123
References: Proceedings of the National Academy of Sciences (June 15)
Image Credits: James Berger
Keywords: DCTPP1; decitabine; prostate cancer; inhibitors; X-ray crystallography; nucleotide-binding pocket; DNA damage; genome integrity; chemotherapy sensitization; treatment resistance