{
  "id": 10443349,
  "title": "PGG Enhances Olaparib Efficacy via cGAS-STING Signaling and Sensitizes Triple-Negative Breast Cancer to PD- L1 Blockade",
  "url": "https://urgent.news/2026/09/28/pgg-enhances-olaparib-efficacy-via-cgas-sting-signaling-and",
  "topic": "health",
  "section": "Health & Medicine",
  "published": "2026-09-28T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.26.752069v1?rss=1"
  },
  "original_language": "en",
  "account": "Triple-negative breast cancer (TNBC) presents a formidable challenge due to its aggressive nature and limited targeted therapy options. While PARP inhibitors such as olaparib (Ola) exploit synthetic lethality, their clinical effectiveness is diminished by drug resistance and the rarity of BRCA mutations. In a groundbreaking study, researchers investigated the potential of 1,2,3,4,6-penta-O-galloyl-{beta}-D-glucose (PGG), a natural polyphenolic compound, to enhance Ola's efficacy in TNBC cells. PGG triggers a state of homologous recombination deficiency (HRD) by disrupting the PALB2-BRCA2 interaction, rendering cells more susceptible to Ola's effects. This dual therapy led to heightened oxidative stress, mitochondrial dysfunction, and accelerated apoptosis, ultimately promoting immunogenic cell death and the release of immunogenic cell death (ICD)-associated damage-associated molecular patterns (DAMPs). The resulting surge in cytosolic double-stranded DNA activated the innate immune cGAS-STING pathway, driving robust immune cell infiltration into the tumor microenvironment. Intriguingly, cGAS-STING hyperactivation induced compensatory PD-L1 upregulation on TNBC cells, making them more susceptible to anti-PD-L1 antibody treatment. When combined with Ola and PGG, this strategy resulted in near-total tumor eradication and maximal cytotoxic T cell infiltration. Moreover, bioinformatics analyses identified potential targets associated with extracellular matrix organization and stromal tension, offering a bioinformatics-derived rationale for investigating the tumor microenvironment. In summary, this study unveils PGG as a multi-functional therapeutic agent that combines intracellular synthetic lethality, innate immune sensing, and microenvironmental remodeling to transform immunologically \"cold\" TNBC into a \"hot\" tumor environment, paving the way for innovative treatment strategies.",
  "summary": "Triple-negative breast cancer (TNBC) is a highly aggressive malignancy and options for targeted therapy are limited. Although PARP inhibitors (PARPi) like olaparib (Ola) leverage synthetic lethality, their clinical utility is severely impeded by drug resistance and low frequency of BRCA mutations. In this study, 1,2,3,4,6-penta-O-galloyl-{beta}-D-glucose (PGG), a natural polyphenolic compound,…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 2,
    "also_reported_by": [
      {
        "outlet": "bioRxiv",
        "title": "Palmitate-activated IRE1-XBP1 signaling limits DNA damage and is associated with H2A.X-linked DNA damage response transcripts in triple-negative breast cancer cells",
        "url": "https://urgent.news/2026/09/28/palmitate-activated-ire1-xbp1-signaling-limits-dna-damage-and-is",
        "published": "2026-09-28T00:00:00.000Z"
      }
    ]
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}