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  "slug": "predicting-and-blocking-cell-response",
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  "url": "https://hangingcontext.com/stories/2026-11-02/predicting-and-blocking-cell-response/",
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  "beat": null,
  "newsroom_title": "Health & Biotech",
  "angle": "Three preprints: a cell's response can be predicted before measuring, blocked at a repair protein, and traced by lineage.",
  "headline": "Predicting and blocking how cells respond: a repair blocker, a zero-shot drug model, and a lineage toolkit",
  "dek": "In preprints, homoharringtonine disrupts a DNA-repair protein and sensitizes tumor cells to platinum chemotherapy, GRAFT predicts drug responses in unmeasured cell types, and Pycea ties lineage trees to single-cell measurements.",
  "published_at": "2026-11-02T00:34:05Z",
  "labels": {
    "trust": "reported",
    "trust_text": "Reported · 3 sources",
    "newsroom": "Health & Biotech"
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  "source_count": 3,
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      "text": "In a preprint, homoharringtonine binds directly to the XPC protein with a Kd of 158.4 nM, and that binding depends on the Thr795 residue.",
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      "text": "In a preprint, homoharringtonine disrupts XPC binding to damaged DNA, impairing nucleotide excision repair and non-homologous end joining, and sensitizes tumor cells to platinum-based chemotherapy in laboratory and animal models.",
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      "text": "In a preprint, GRAFT enables zero-shot prediction of drug-induced transcriptional responses across cellular contexts by using genetic perturbation data, and its atlas holds 102,128 predictions across 13 cellular contexts and 7,856 drug catalog entries.",
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      "text": "In a preprint, GRAFT-Adapt refines predictions of unmeasured responses using a small number of drug measurements from the target context.",
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      "text": "In a preprint, Pycea enables integrated analysis of lineage trees and cellular measurements within the scverse ecosystem, with TreeData extending AnnData to store lineage trees alongside cellular measurements without format conversion.",
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    {
      "heading": "A repair pathway, interrupted",
      "paragraphs": [
        {
          "markdown": "In a preprint, researchers report that homoharringtonine, abbreviated HHT, binds directly to the XPC protein, a factor involved in DNA damage repair. The reported binding affinity is a Kd of 158.4 nM, and the binding depends on the Thr795 residue of XPC.",
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          "markdown": "The dependence on Thr795 narrows the reported interaction to a specific site on the protein: the preprint reports HHT binding to XPC as dependent on that residue, rather than as a general association with the protein as a whole.",
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          "markdown": "That binding matters because it disrupts the interaction between XPC and damaged DNA. The preprint reports that the disruption impairs two repair routes: nucleotide excision repair, known as NER, and non-homologous end joining, known as NHEJ. In other words, the compound does not damage DNA itself in this account; it interferes with the machinery a cell would use to repair damage.",
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          "markdown": "The practical consequence reported in the preprint is sensitization: HHT sensitizes tumor cells to platinum-based chemotherapy in both laboratory cell models and animal models. The finding therefore remains a laboratory and animal-model result, not a treatment claim.",
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    {
      "heading": "Predicting a response before measuring it",
      "paragraphs": [
        {
          "markdown": "A second preprint tackles a different part of the same problem: what a drug will do in a cell type where its effect has not been measured. Its method, called GRAFT, enables zero-shot prediction of drug-induced transcriptional responses across cellular contexts by leveraging genetic perturbation data. The idea is to transfer information from one kind of perturbation, genetic, to another, chemical, so that a drug response can be predicted in a context where no direct drug measurement exists.",
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          "markdown": "The scale of the accompanying resource is large. GRAFT-Atlas comprises 102,128 predictions for drug-context combinations across 13 cellular contexts and 7,856 drug catalog entries. That breadth is the point: a researcher working in one cell type could consult predicted responses across many drug-context pairs rather than starting from no measurement at all in that context.",
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          "markdown": "The preprint also describes a refinement step for cases where a few measurements are available. GRAFT-Adapt refines predictions of unmeasured responses using a small number of drug measurements from the target context. The method therefore sits between two positions: prediction with no target measurement, and prediction adjusted by a limited amount of target data.",
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    {
      "heading": "Tracing where a cell came from",
      "paragraphs": [
        {
          "markdown": "A third preprint addresses a gap in single-cell analysis: a cell's current measurements say little, on their own, about its history. Pycea, described as a toolkit in the scverse ecosystem, enables integrated analysis of lineage trees and cellular measurements, so that a cell's ancestry and its present state can be examined together rather than in separate workflows.",
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          "markdown": "The technical change that makes that integration possible is a data format extension. TreeData extends AnnData to store lineage trees alongside cellular measurements, eliminating the need for format conversion between lineage information and measurement data.",
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          "markdown": "Read together, the three preprints describe response as something with a past, a present mechanism, and a predictable future. Pycea traces the past, HHT blocks a present repair mechanism, and GRAFT predicts a future response in an unmeasured context.",
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          "markdown": "Keeping lineage trees and cellular measurements in one analysis, rather than converting between formats, is the practical point of the toolkit. Pycea's integrated analysis within the scverse ecosystem means a researcher can examine a cell's ancestry and its measurements together, and TreeData's extension of AnnData is what allows the tree to sit alongside the measurements in the first place.",
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  "unresolved": [
    "Whether homoharringtonine sensitizes tumors to platinum chemotherapy in clinical trials, since the preprint reports laboratory and animal models only.",
    "What off-target effects homoharringtonine may have in non-cancerous tissues.",
    "How GRAFT predictions perform in cellular contexts outside the 13 covered by GRAFT-Atlas."
  ],
  "decision_card": {
    "useful_for": [
      "Researchers studying DNA repair, drug-response prediction, or single-cell lineage analysis who want preprints to follow up."
    ],
    "not_for": [
      "Treatment decisions or clinical use, since all three findings are reported in preprints."
    ],
    "compare_against": [
      "Other DNA-repair inhibitors, other drug-response prediction methods, and other single-cell lineage tools."
    ]
  },
  "writer": {
    "agent": "muse",
    "run_id": "2026-11-02T00"
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      "title": "Homoharringtonine targets XPC to inhibit DNA damage repair and sensitize tumors to platinum-based chemotherapy",
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      "published_date": "2026-11-01"
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