STING activation disrupts tumor vasculature to overcome the EPR limitation and increase drug deposition.

The low success rate of cancer nanomedicines has raised debate on the role of the enhanced permeability and retention (EPR) effect on tumor deposition of nanotherapeutics. Here, we report a bifunctional nanoscale coordination polymer (NCP), oxaliplatin (OX)/2',3'-cyclic guanosine monophosphate-adenosine monophosphate (GA), to overcome the EPR limitation through stimulator of interferon genes (STING) activation and enhance chemotherapeutic and STING agonist delivery for tumor eradication. OX/GA encapsulates GA and OX in the NCP to protect GA from enzymatic degradation and improve GA and OX pharmacokinetics. STING activation by OX/GA disrupts tumor vasculatures and increases intratumoral deposition of OX by 4.9-fold over monotherapy OX-NCP. OX/GA demonstrates exceptional antitumor effects with >95% tumor growth inhibition and high cure rates in subcutaneous, orthotopic, spontaneous, and metastatic tumor models. OX/GA induces immunogenic cell death of tumor cells and STING activation of innate immune cells to enhance antigen presentation. NCPs provide an excellent nanoplatform to overcome the EPR limitation for effective cancer therapy.

Nanoscale Metal-Organic Layer Reprograms Cellular Metabolism to Enhance Photodynamic Therapy and Antitumor Immunity.

Abnormal cancer metabolism causes hypoxia and immunosuppressive tumor microenvironment (TME), which limits the antitumor efficacy of photodynamic therapy (PDT). Herein, we report a photosensitizing nanoscale metal-organic layer (MOL) with anchored 3­bromopyruvate (BrP), BrP@MOL, as a metabolic reprogramming agent to enhance PDT and antitumor immunity. BrP@MOL inhibited mitochondrial respiration and glycolysis to oxygenate tumors and reduce lactate production. This metabolic reprogramming enhanced reactive oxygen species generation during PDT and reshaped the immunosuppressive TME to enhance antitumor immunity. BrP@MOL-mediated PDT inhibited tumor growth by >90% with a 40% cure rate, rejected tumor re-challenge, and prevented lung metastasis. Further combination with immune checkpoint blockade potently regressed the tumors with >98% tumor inhibition and an 80% cure rate.

STING agonist-conjugated metal-organic framework induces artificial leukocytoid structures and immune hotspots for systemic antitumor responses.

Radiotherapy is widely used for cancer treatment, but its clinical utility is limited by radioresistance and its inability to target metastases. Nanoscale metal-organic frameworks (MOFs) have shown promise as high-Z nanoradiosensitizers to enhance radiotherapy and induce immunostimulatory regulation of the tumor microenvironment. We hypothesized that MOFs could deliver small-molecule therapeutics to synergize with radiotherapy for enhanced antitumor efficacy. Herein, we develop a robust nanoradiosensitizer, GA-MOF, by conjugating a STING agonist, 2',3'-cyclic guanosine monophosphate-adenosine monophosphate (GA), on MOFs for synergistic radiosensitization and STING activation. GA-MOF demonstrated strong anticancer efficacy by forming immune-cell-rich nodules (artificial leukocytoid structures) and transforming them into immunostimulatory hotspots with radiotherapy. Further combination with an immune checkpoint blockade suppressed distant tumors through systemic immune activation. Our work not only demonstrates the potent radiosensitization of GA-MOF, but also provides detailed mechanisms regarding MOF distribution, immune regulatory pathways and long-term immune effects.

Phosphate Coordination to Metal-Organic Layer Secondary Building Units Prolongs Drug Retention for Synergistic Chemoradiotherapy.

Chemoradiotherapy combines radiotherapy with concurrent chemotherapy to potentiate antitumor activity but exacerbates toxicities and causes debilitating side effects in cancer patients. Herein, we report the use of a nanoscale metal-organic layer (MOL) as a 2D nanoradiosensitizer and a reservoir for the slow release of chemotherapeutics to amplify the antitumor effects of radiotherapy. Coordination of phosphate-containing drugs to MOL secondary building units prolongs their intratumoral retention, allowing for continuous release of gemcitabine monophosphate (GMP) for effective localized chemotherapy. In the meantime, the MOL sensitizes cancer cells to X-ray irradiation and provides potent radiotherapeutic effects. GMP-loaded MOL (GMP/MOL) enhances cytotoxicity by 2-fold and improves radiotherapeutic effects over free GMP in vitro. In a colon cancer model, GMP/MOL retains GMP in tumors for more than four days and, when combined with low-dose radiotherapy, inhibits tumor growth by 98 %. The synergistic chemoradiotherapy enabled by GMP/MOL shows a cure rate of 50 %, improves survival, and ameliorates cancer-proliferation histological biomarkers.

Nanoscale coordination polymer synergizes photodynamic therapy and toll-like receptor activation for enhanced antigen presentation and antitumor immunity.

While activating antitumor immunity with toll-like receptor (TLR) agonists provides a promising approach toward cancer immunotherapy, existing TLR agonists, including resiquimod (R848), have shown poor tumor selectivity and ineffective TLR activation in tumors for optimal antitumor effects. We hypothesized that improved delivery of TLR agonists to tumors and their effective combination with tumor antigens could significantly enhance their antitumor efficacy. Here, we report a novel nanoscale coordination polymer, Ce6/R848, for the co-delivery of Ce6 photosensitizer to elicit immunogenic cell death via photodynamic therapy (PDT) and cholesterol-conjugated R848 (Chol-R848) for tumor-selective TLR7/8 activation. Upon light irradiation, Ce6-mediated PDT released tumor antigens while selectively delivered R848 activated TLR7/8 in the tumors to synergistically activate antigen-presenting cells and prime T cells for enhanced innate and adaptive antitumor immune responses. Ce6/R848 achieved a 50% cure rate and 99.4% inhibition of tumor growth in subcutaneous MC38 colorectal tumors with minimal systemic toxicity.

Co-delivery of three synergistic chemotherapeutics in a core-shell nanoscale coordination polymer for the treatment of pancreatic cancer.

The combination chemotherapy regimen FOLFIRINOX comprising folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin is the first-line treatment for patients with advanced pancreatic cancer, but its use remains prohibitive for the majority of patients due to severe side effects. Here, we report a core-shell nanoscale coordination polymer (NCP) nanoparticle co-delivering a potent and synergistic combination of oxaliplatin, gemcitabine, and SN38 (OGS), for the treatment of pancreatic cancer in mouse models. OGS contains key synergistic components of FOLFIRINOX in a controllable drug ratio., It exhibited particle stability in blood circulation and enhanced deposition of the drugs in acidic tumor environments. In vitro, OGS showed superior cytotoxicity over free drug combinations and robust cytotoxic synergism among its three components. In vivo, OGS improved drug circulation, increased tumor deposition, and exhibited superior antitumor efficacy over the free drug combination in both subcutaneous and orthotopic pancreatic tumor models. OGS treatment achieved 75-91% tumor growth inhibition and prolonged mouse survival by 1.6- to 2.8-folds while minimizing systemic toxicities such as neutropenia, hepatotoxicity, and renal toxicity. This work uncovers a novel and clinically relevant nanomedicine strategy to co-deliver synergistic combination chemotherapies for difficult-to-treat cancers.