Normalization Of Tumor Vasculature Research Articles

A Wurster-Type Covalent Organic Framework with Internal Electron Transfer-Enhanced Catalytic Capacity for Tumor Therapy.

The low immunogenicity of tumors, along with the abnormal structural and biochemical barriers of tumor-associated vasculature, impedes the infiltration and function of effector T cells at the tumor site, severely inhibiting the efficacy of antitumor immunotherapy. In this study, a cobaloxime catalyst and STING agonist (MSA-2)-coloaded Wurster-type covalent organic framework (Co-TB COF-M) with internal electron transfer-enhanced catalytic capacity was developed as a COF-based immune activator. The covalently anchored cobaloxime adjusts the energy band structure of TB COF and provides it with good substrate adsorption sites, enabling it to act as an electron transmission bridge between the COF and substrate in proton reduction catalytic reactions. This property significantly enhances the sonodynamic catalytic performance. Under sono-irradiation, Co-TB COF-M can produce a substantial amount of reactive oxygen species (ROS) to induce Gasdermin D-mediated pro-inflammatory pyroptosis, thereby effectively enhancing the immunogenicity of tumors. Furthermore, MSA-2 is specifically released in response to ROS at the tumor site, minimizing the off-target side effects. More importantly, Co-TB COF-induced STING activation normalizes tumor vasculature and increases the expression of endothelial T cell adhesion molecules, which greatly enhance the infiltration and function of effector T cells. Thus, Co-TB COF-M as an immune activator could remold the tumor microenvironment, leading to increased infiltration and an improved function of T cells for immunotherapy.

Taohong Siwu decoction enhances the chemotherapeutic efficacy of doxorubicin by promoting tumor vascular normalization

BackgroundInstead of completely suppressing blood vessels inside tumors, vascular normalization therapy is proposed to normalize and prune the abnormal vasculature in tumor microenvironment (TME) to acquire a normal and stable blood flow and perfusion. The theoretical basis for the use of “blood-activating and stasis-resolving” formulas in Traditional Chinese Medicine to treat cancer is highly consistent with the principle of vascular normalization therapy, suggesting the potential application of these traditional formulas in vascular normalization therapy. PurposeTo study the underlying mechanisms of a classical “blood-activating and stasis-resolving” formula, Taohong Siwu decoction (TSD), in enhancing the efficacy of chemotherapy for breast cancer treatment. Study designHUVECs and transgenic zebrafish embryos were used as the major model in vitro. A 4T1 mouse breast cancer model was applied to study tumor vasculature normalization of TSD and the combination effects with DOX. ResultsOur data showed that TSD exhibited anti-angiogenic potential in HUVECs and transgenic zebrafish embryos. After 20 days treatment, TSD significantly normalized the tumor vasculature by remodeling vessel structure, reducing intratumoral hypoxia and vessel leakage, and promoting vessel maturation and blood perfusion in 4T1 breast tumor-bearing mice. Moreover, the anti-tumor efficacy of doxorubicin liposome in 4T1 breast tumors was significantly improved by TSD, including the suppression of tumor cell proliferation, angiogenesis, hypoxia, and the increase of cell apoptosis, which is likely through the vascular normalization induced by TSD. TSD also shifted the macrophage polarization from M2 to M1 phenotype in TME during the combination therapy, as evidenced by the reduced number of CD206+ macrophages and increased number of CD86+ macrophages. Additionally, TSD treatment protected against doxorubicin-induced cardiotoxicity in animals, as evidenced by the reduced cardiomyocytes apoptosis and improved heart function. ConclusionThis study demonstrated for the first time that TSD as a classical Chinese formula can enhance the drug efficacy and reduce the side effects of doxorubicin. These findings can support that TSD could be used as an adjuvant therapy in combination with conventional chemotherapy for the future breast cancer treatment.

Targeting RhoA expression with formononetin and salvianolic acid B to mitigate pancreatic cancer-associated endothelial cells changes

Ethnopharmacological relevanceAccording to the theory of Qi and blood in Traditional Chinese Medicine (TCM), the combination of Qi-reinforcing herbs and blood-activating herbs has a synergistic effect in improving blood stasis syndrome, especially in tumor treatment. The classic “Radix Astragali - Salvia miltiorrhiza” duo exemplifies this principle, renowned for invigorating Qi and activating blood flow, employed widely in tumor therapies. Our prior research underscores the potent inhibition of pancreatic tumor xenografts by the combination of Formononetin (from Radix Astragali) and Salvianolic acid B (from Salvia miltiorrhiza) in vitro. However, it remains unclear whether this combination can inhibit the abnormal vascularization of pancreatic tumors to achieve its anti-cancer effect. Aim of the studyAbnormal vasculature, known to facilitate tumor growth and metastasis. Strategies to normalize tumor-associated blood vessels provide a promising avenue for anti-tumor therapy. This study aimed to unravel the therapeutic potential of Formononetin combined with Salvianolic acid B (FcS) in modulating pancreatic cancer's impact on endothelial cells, illuminate the underlying mechanisms that govern this therapeutic interaction, thereby advancing strategies to normalize tumor vasculature and combat cancer progression. Materials and methodsA co-culture system involving Human Umbilical Vein Endothelial Cells (HUVECs) and PANC-1 cells was established to investigate the potential of targeting abnormal vasculature as a novel anti-tumor therapeutic strategy. We systematically compared HUVEC proliferation, migration, invasion, and lumenogenesis in both mono- and co-culture conditions with PANC-1 (H-P). Subsequently, FcS treatment of the H-P system was evaluated for its anti-angiogenic properties. Molecular docking was utilized to predict the interactions between Formononetin and Salvianolic acid B with RhoA, and the post-treatment expression of RhoA in HUVECs was assessed. Furthermore, we utilized shRhoA lentivirus to elucidate the role of RhoA in FcS-mediated effects on HUVECs. In vivo, a zebrafish xenograft tumor model was employed to assess FcS's anti-tumor potential, focusing on cancer cell proliferation, migration, apoptosis, and vascular development. ResultsFcS treatment demonstrated a significant, dose-dependent inhibition of PANC-1-induced alterations in HUVECs, including proliferation, migration, invasion, and tube formation capabilities. Molecular docking analyses indicated potential interactions between FcS and RhoA. Further, FcS treatment was found to downregulate RhoA expression and modulated the PI3K/AKT signaling pathway in PANC-1-induced HUVECs. Notably, the phenotypic inhibitory effects of FcS on HUVECs were attenuated by RhoA knockdown. In vivo zebrafish studies validated FcS's anti-tumor activity, inhibiting cancer cell proliferation, metastasis, and vascular sprouting, while promoting tumor cell apoptosis. ConclusionsThis study underscores the promising potential of FcS in countering pancreatic cancer-induced endothelial alterations. FcS exhibits pronounced anti-abnormal vasculature effects, potentially achieved through downregulation of RhoA and inhibition of the PI3K/Akt signaling pathway, thereby presenting a novel therapeutic avenue for pancreatic cancer management.

Endothelial cell-specific LAT1 ablation normalizes tumor vasculature.

Some endothelial cells in the tumor vasculature express a system L amino acid transporter, LAT1. To elucidate the role of LAT1 in tumor-related endothelial cells, tumor cells were injected into endothelial cell-specific LAT1 conditional knockout mice (Slc7a5flox/flox; Cdh5-Cre-ERT2), and we found that the shape of the tumor vasculature was normalized and the size and numbers of lung metastasis was reduced. TNF-α-induced expression of VCAM1 and E-selectin at the surface of HUVEC, both of which are responsible for enhanced monocyte attachment and premetastatic niche formation, was reduced in the presence of LAT1 inhibitor, nanvuranlat. Deprivation of tryptophan, a LAT1 substrate, mimicked LAT1 inhibition, which led to activation of MEK1/2-ERK1/2 pathway and subsequent cystathionine γ lyase (CTH) induction. Increased production of hydrogen sulfide (H2S) by CTH was at least partially responsible for tumor vascular normalization, leading to decreased leakiness and enhanced delivery of chemotherapeutic agents to the tumor.

VAMANA: A phase 2 study of low-dose bevacizumab plus CCNU in relapsed/recurrent glioblastoma.

LBA2064 Background: There are limited systemic therapy options for recurrent glioblastomas (rGBM). CCNU and/or Bevacizumab are often used to treat rGBM not amenable to local therapy. The addition of Bevacizumab (10 mg/kg) to CCNU failed to improve overall survival in the EORTC 26101 study. The question is whether the failure was due to the high dose of Bevacizumab used in the study. High doses of Bevacizumab may lead to excessive pruning & destruction of blood vessels, hampering the delivery of CCNU. In vitro & in vivo studies showed that a lower dose of Bevacizumab (1-1.5 mg/kg) has the potential to normalize tumor vasculature leading to improved drug delivery & outcomes. To test this hypothesis, we conducted this study to evaluate the efficacy of low-dose Bevacizumab in combination with CCNU in rGBM. Methods: This was a phase 2 open-label, single-arm trial that included adults with rGBM with an ECOG PS 0-2 and adequate organ & marrow function. The participants received CCNU 110 mg/m2 PO once a day, on day 1 of a 42-day cycle (max. 8 cycles) with Bevacizumab 1.5 mg/kg intravenously every 3 weeks (max.16 cycles). Appropriate anti-emetic prophylaxis was given. Treatment continued until disease progression, clinical deterioration, or development of intolerable side effects. Response assessment was done with MRI Brain +/- spine at 2 monthly intervals till disease progression. The modified RANO criteria were used for response assessment. Safety assessments were done on day 8 of cycle 1, & days 21 & 42 of each cycle. The primary end-point of this study was overall survival (OS) and secondary end-points were progression-free survival (PFS) & safety. A 6-month OS ≥ 40% was the signal to explore this regimen further and if the 6-month OS <20% it would be considered futile. Descriptive statistics were performed and the Kaplan-Meier method was used for time-to-event analysis. Results: Forty-six patients were enrolled in this study. The median age was 42 years (IQR 33-52.75) and 78.3% (36/46) were males. Most patients (76.1%, 35/46) had an ECOG PS of 1. The median follow-up duration was 15.27 months (95% CI 13.47-17.06). The median number of doses of Bevacizumab and CCNU were 4 and 2 respectively. Three (6.5%) patients completed all planned doses of Bevacizumab and CCNU. The objective response rate (ORR) was 15.2 % (7/46). The median OS was 6.133 months (95% CI 5.474-6.793). The 6-month OS was 57.1%. The median PFS was 3.267 months (95% CI 0.850-5.684). The most frequent grade 3 or higher toxicities seen were neutropenia (7/46, 15.2%), thrombocytopenia (5/46,10.8%), elevated ALT levels (3/46, 6.5%), anemia (2/46, 4.3%) and hyponatremia (2/46, 4.3%). Conclusions: This study demonstrates the efficacy of low-dose Bevacizumab in combination with CCNU in rGBM (the median OS exceeded the preplanned cut-off of 40%) with an acceptable toxicity profile and no new safety signals. This combination should be explored further in a phase III randomized study. Clinical trial information: CTRI/2020/07/026696 .

Identification of hypoxic macrophages in glioblastoma with therapeutic potential for vasculature normalization

Monocyte-derived tumor-associated macrophages (Mo-TAMs) intensively infiltrate diffuse gliomas with remarkable heterogeneity. Using single-cell transcriptomics, we chart a spatially resolved transcriptional landscape of Mo-TAMs across 51 patients with isocitrate dehydrogenase (IDH)-wild-type glioblastomas or IDH-mutant gliomas. We characterize a Mo-TAM subset that is localized to the peri-necrotic niche and skewed by hypoxic niche cues to acquire a hypoxia response signature. Hypoxia-TAM destabilizes endothelial adherens junctions by activating adrenomedullin paracrine signaling, thereby stimulating a hyperpermeable neovasculature that hampers drug delivery in glioblastoma xenografts. Accordingly, genetic ablation or pharmacological blockade of adrenomedullin produced by Hypoxia-TAM restores vascular integrity, improves intratumoral concentration of the anti-tumor agent dabrafenib, and achieves combinatorial therapeutic benefits. Increased proportion of Hypoxia-TAM or adrenomedullin expression is predictive of tumor vessel hyperpermeability and a worse prognosis of glioblastoma. Our findings highlight Mo-TAM diversity and spatial niche-steered Mo-TAM reprogramming in diffuse gliomas and indicate potential therapeutics targeting Hypoxia-TAM to normalize tumor vasculature.

Three-in-one erlotinib-modified NIR photosensitizer for fluorescence imaging and synergistic chemo-photodynamic therapy

Photodynamic therapy (PDT) presents a promising avenue in cancer treatment. Erlotinib, an FDA-approved anticancer drug targeting epidermal growth factor receptor (EGFR), has shown effectiveness in normalizing tumor vasculature across various tumors, thereby promoting tumor oxygenation and facilitating PDT. In this work, erlotinib was conjugated with a near-infrared (NIR) photosensitizer, benzo[a]phenoselenazinium, yielding three EGFR-targeted PDT agents (NBSe-nC-Er). These newly synthesized photosensitizers demonstrate specificity in binding to EGFR, thereby enhancing their accumulation in cancer cells and tumors, and consequently improving the efficiency of both PDT and chemotherapy. Additionally, the NIR fluorescence emitted by the photosensitizer allows for imaging-guided therapy, offering a non-invasive means of monitoring treatment progress. The distinctive properties of the three-in-one photosensitizer render it an ideal candidate for precise tumor treatment, overcoming the limitations of conventional therapies.

Abstract 3997: PARP inhibitors plus anlotinib as bridging therapy for TGFβ-insensitive CAR-T cell therapy targeting MSLN and CD19 in advanced ovarian cancer

Abstract Background: The efficacy of chimeric antigen receptor (CAR) T cell therapy remains modest for the treatment of solid tumors due to restricted T cell infiltration and immunosuppressive tumor microenvironment (TME). Leveraging the window of opportunity between leukapheresis and infusion using bridging therapy might improve TME and potentiate CAR-T cell therapy. Here, we assessed the potential of poly (ADP-ribose) polymerase (PARP) inhibitors plus anlotinib as bridging therapy for CAR-T cells with resistance to TGFβ and capability of rapid expansion by bait-and-switch strategy of dual-targeting mesothelin (MSLN) and CD19 in preclinical models of advanced ovarian cancer. Methods: Immunocompetent mice bearing ID8 tumors were treated with niraparib (21 days) plus anlotinib (14 days) and euthanized at different timepoints (0, 7, or 14 days since discontinuation) to quantify tumor-infiltrating T cells and profile T cell functions. CAR-T cells transfected with dominant-negative TGFβRII dual-targeting MSLN and CD19 were produced by IASO Biotherapeutics. NSG mice bearing MSLN-positive cell- or patient-derived xenografts (CDX or PDX) of ovarian cancer received CAR-T cells alone or after bridging therapy (niraparib plus anlotinib followed by a wash-out period of 7 days). Tumor volume was balanced before CAR-T cell infusion. Replication-deficient NALM6 cells pre-treated with mitomycin C were injected to provide CD19 antigen. A PET scan that visualized granzyme B release was used to track CAR-T cells and assess immune-mediated tumor killing. Results: Niraparib combined with anlotinib increased tumor-infiltrating T cells without impairing T cell functionality. The effects of promoting T cell infiltration remained significant at 14 days after discontinuation, which might associate with lasting activation of cGAS-STING pathway and secretion of downstream chemokines (CXCL10 and CCL5), and normalized tumor vasculature featured by better perfusion and reduced leakage. The engineered CAR-T cells could resist TGFβ and displayed improved proliferation, cytotoxicity, cytokine release, and in vivo antitumor activities upon CD19 stimulation. Importantly, bridging therapy significantly increased CAR-T cell infiltration, curbed tumor growth, and prolonged survival in mice bearing SKOV3 CDX, HRD-negative PDX, and another multidrug-resistant PDX. PET imaging showed that bridging therapy increased tumor-infiltrating CAR-T cells and boosted tumor-killing capability. Conclusions: PARP inhibitors plus anlotinib as bridging therapy facilitated CAR-T cell infiltration and enhanced antitumor activities in multiple preclinical models of advanced ovarian cancer, and an early phase I trial (NCT05141253) is ongoing to evaluate PARP inhibitors plus anlotinib as bridging therapy for CAR-T cell therapy in patients with refractory MSLN-positive ovarian cancer. Citation Format: Huayi Li, Minghua Xiang, Jiahao Liu, Wei Mu, Li Zhu, Xuejiao Zhao, Gordon B. Mills, Qinglei Gao, Yong Fang. PARP inhibitors plus anlotinib as bridging therapy for TGFβ-insensitive CAR-T cell therapy targeting MSLN and CD19 in advanced ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3997.

Engineering tumor-oxygenated nanomaterials: advancing photodynamic therapy for cancer treatment.

Photodynamic therapy (PDT), a promising treatment modality, employs photosensitizers to generate cytotoxic reactive oxygen species (ROS) within localized tumor regions. This technique involves administering a photosensitizer followed by light activation in the presence of oxygen (O2), resulting in cytotoxic ROS production. PDT's spatiotemporal selectivity, minimally invasive nature, and compatibility with other treatment modalities make it a compelling therapeutic approach. However, hypoxic tumor microenvironment (TME) poses a significant challenge to conventional PDT. To overcome this hurdle, various strategies have been devised, including in-situ O2 generation, targeted O2 delivery, tumor vasculature normalization, modulation of mitochondrial respiration, and photocatalytic O2 generation. This review aims to provide a comprehensive overview of recent developments in designing tumor-oxygenated nanomaterials to enhance PDT efficacy. Furthermore, we delineate ongoing challenges and propose strategies to improve PDT's clinical impact in cancer treatment.

Abstract A041: Vascular normalization improves the delivery and efficacy of CAR-T cells in mouse brain cancers

Abstract Introduction: Chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment of hematological malignancies, but its efficacy in patients with glioblastoma (GBM) and other solid tumors is limited due to poor tumor infiltration and an immunosuppressive tumor microenvironment (TME). We have previously shown that blocking vascular endothelial growth factor (VEGF) signaling can normalize tumor vessels, convert the immunosuppressive TME into an immunostimulatory environment, and enhance the efficacy of immunotherapy. This study aimed to investigate whether combining anti-VEGF therapy (B20) with EGFRvIII-targeting CAR-T cell treatment could improve delivery and effectiveness in immunocompetent orthotopic GBM mouse models. Methods: The study utilized two syngeneic mouse GBM cell lines (CT2A and GSC005) engineered to express EGFRvIII, a common neoantigen in human GBM. CAR-T cells were designed to target EGFRvIII. GBM-bearing mice were treated with B20[LS1] followed by EGFRvIII-CAR-T injection. Intravital imaging using two-photon microscopy was employed to track CAR-T cell infiltration into the tumor, while flow cytometry was used to measure the number and function of CAR-T and other immune cells. Results: The combination of B20 and CAR-T cell treatment significantly prolonged the survival of GBM-bearing mice compared to CAR-T cell therapy alone. Intravital imaging revealed that B20 normalized tumor vasculature, leading to a four-fold increase in the number of infiltrated CAR-T cells compared to CAR-T therapy without B20. Flow cytometry analysis showed an increased population of IL-2+ or IFN-γ+ CAR-T cells, indicating that B20 enhanced the anti-tumor function of injected CAR-T cells. Additionally, B20 therapy increased the population of endogenous lymphocytes, specifically Granzyme B+ TNF-α+ CD8 T cells (Cytotoxic T lymphocytes; CTLs) while decreasing FoxP3+ CD4 T cells (Regulatory T cells; Tregs). This indicated that the TME was remodeled to enhance the effect of CAR-T therapy. Conclusions: Our study demonstrated that combining B20 with CAR-T therapy improved their efficacy in GBM mouse models by enhancing CAR-T cell infiltration and reprogramming the TME to activate CAR-T cells and effector T cells. These findings provide compelling evidence for clinically evaluating the combination of anti-VEGF agents with CAR-T cells in GBM patients. We are now building on this approach to enhance CAR-T therapy for breast cancer brain metastasis. We are testing TNBC-targeting CAR-T therapy in murine TNBC-BrM[LS2] using a similar approach. Our hypothesis is that similar to the GBM results, anti-VEGF therapy and adoptive transfer of TNBC-targeting CAR-T cells [LS3] will improve CAR-T cell infiltration, delay tumor growth and prolong survival. This strategy has the potential to enhance emerging cellular immunotherapies' effectiveness in the brain tumor microenvironment. Citation Format: Vasiliki Salameti, Xinyue Dong, Jun Ren, Zohreh Amoozgar, Somin Lee, Meenal Datta, Sylvie Roberge, Mark Duquette, Dai Fukumura, Rakesh K. Jain. Vascular normalization improves the delivery and efficacy of CAR-T cells in mouse brain cancers [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr A041.

The Combination of Anti-CD47 Antibody with CTLA4 Blockade Enhances Anti-Tumor Immunity in Non-Small Cell Lung Cancer via Normalization of Tumor Vasculature and Reprogramming of the Immune Microenvironment.

In solid tumors, the formidable anti-tumor impact resulting from blocking the "don't eat me" signal, arising from CD47-SIRPα interaction, is constrained, especially compared to its efficacy in hematopoietic malignancies. Activating macrophage anti-tumor activity not only necessitates the inhibition of the "don't eat me" signal, but also the activation of the "eat me" (pre-phagocyte) signal. Intriguingly, the cytotoxic T-lymphocyte-associated antigen 4 (CTLA4) antibody (Ab) has been identified to stimulate Fc receptor-mediated active phagocytes in the tumor microenvironment, thereby generating "eat me" signals. This study postulates that concurrently targeting CD47 and CTLA4 could intensify the anti-tumor effects by simultaneously blocking the "don't eat me" signal while triggering the "eat me" signal. The experimental data from this investigation confirm that the combined targeting of CD47 and CTLA4 enhances immunity against solid tumors in LLC cell-transplanted tumor-bearing mice. This effect is achieved by reducing myeloid-derived suppressor cell infiltration while increasing the presence of effector memory CD8+ T cells, NK1.1+ CD8+ T cells, and activated natural killer T cells. Meanwhile, combination therapy also alleviated anemia. Mechanistically, the anti-CD47 Ab is shown to upregulate CTLA4 levels in NSCLC cells by regulating Foxp1. Furthermore, targeting CD47 is demonstrated to promote tumor vascular normalization through the heightened infiltration of CD4+ T cells. These findings suggest that the dual targeting of CD47 and CTLA4 exerts anti-tumor effects by orchestrating the "eat me" and "don't eat me" signals, reshaping the immune microenvironment, and fostering tumor vascular normalization. This combined therapeutic approach emerges as a potent strategy for effectively treating solid tumors.

Modulation of the Tumor Stroma and Associated Novel Nanoparticle Strategies to Enhance Tumor Targeting

Growth of malignant cells in solid tumors induces changes to the tumor microenvironment (TME). These changes result in promotion of tumor growth, invasion, and metastasis, but also in tumor resistance to drugs and radiotherapy. The enhanced permeability and retention (EPR) effect in neo-angiogenic tumor tissue enables the transport of therapeutic molecules from the circulation into the tumor, but studies show that further diffusion of these agents is often not sufficient for efficient tumor eradication. Despite the hyperpermeable vasculature facilitating the delivery of drugs and tracers, the high density of stromal cells and matrix proteins, in combination with the elevated interstitial fluid pressure in the microenvironment of solid tumors, presents a barrier which limits the delivery of compounds to the core of the tumor. Reversing the cancer-cell-induced changes to the microenvironment as well as novel nanoparticle strategies to circumvent tumor-induced stromal changes have therefore been suggested as potential methods to improve the delivery of therapeutic molecules and drug efficacy. Strategies to modulate the TME, i.e., normalization of tumor vasculature and depletion of excessive stromal proteins and cells, show promising results in enhancing delivery of therapeutic compounds. Modulation of the TME may therefore enhance the efficacy of current cancer treatments and facilitate the development of novel treatment methods as an alternative for invasive resection procedures.

A phase 2 study of fruquintinib in combination with S-1 for second-line treatment of esophageal squamous cell carcinoma after first-line immunotherapy failure.

323 Background: Patients with advanced esophageal squamous carcinoma (ESCC) who experience progression after first-line immunotherapy face a challenging treatment landscape. The potential of anti-vascular therapy combined with chemotherapy in the treatment of esophageal cancer is well-established. Mechanistically, anti-angiogenic agents can promote the normalization of tumor vasculature and facilitate the access of chemotherapeutic agents to tumor targets. Considering the compromised physical condition of advanced ESCC patients, there is a preference for more convenient oral medications. Therefore, we conducted this phase II study to assess the clinical efficacy and safety of combining fruquintinib with S-1 in treating advanced ESCC patients following first-line immunotherapy failure. Methods: This open-label, single-arm, phase II study consists of dose-finding and dose-expansion phases, enrolling advanced or metastatic ESCC patients after first-line immunotherapy failure. The dose-finding phase followed a 3+3 design. Patients received fruquintinib (3mg, 4mg, 5mg, d1-d14, q3w, respectively), in combination with S-1 (40mg, 50mg, 60mg, bid, d1-d14, q3w, based on body surface area (BSA)), until unacceptable toxicities, progressive disease, or death. The initial fruquintinib dose was 4 mg d1-d14, q3w, in combination with an appropriate S-1 dose. Additional patients were enrolled in the dose-expansion phase and received the maximum tolerated dose determined in the dose-finding phase. Results: As of August 1, 2023, seven patients were enrolled in the dose-finding phase. One patient withdrew consent during the DLT assessment period. Among the patients administered a 4mg dose of fruquintinib, one out of three achieved a confirmed partial response (PR) after 7 cycles of treatment. Additionally, two out of three patients at the 5mg dose level achieved PR after 2 cycles of treatment, resulting in an overall response rate (ORR) of 50% (3/6). The disease control rate (DCR) was 100% (6/6). The median progression-free survival (PFS) was observed to be 4.93 months (95% CI: 1.93 – 10.73), with overall survival (OS) at 10.73 months (95% CI: 2.1 – 10.73). In terms of safety, no dose-limiting toxicities (DLTs) were reported at 4mg dose level. While DLTs were observed in two out of the three patients at the 5mg dose level. The most common treatment-related adverse events (TRAE) across all grades were fatigue (5/7) and extremity pain (4/7). Grade 3 TRAE were identified in 5 patients, with hypertension (2/7), mucositis (2/7), and fatigue (2/7) being reported. No grade 4 or higher TRAEs were observed. Conclusions: Potential benefits were demonstrated when using fruquintinib in combination with S-1 for the treatment of ESCC patients after immunotherapy failure. The efficacy and safety of fruquintinib and S-1 will be further investigated in this trial later. Clinical trial information: NCT05636150 .

Hypoxia-activated prodrug and antiangiogenic therapies cooperatively treat pancreatic cancer but elicit immunosuppressive G-MDSC infiltration.

We previously showed that ablation of tumor hypoxia can sensitize tumors to immune checkpoint blockade (ICB). Here, we used a Kras+/G12D TP53+/R172H Pdx1-Cre-derived (KPC-derived) model of pancreatic adenocarcinoma to examine the tumor response and adaptive resistance mechanisms involved in response to 2 established methods of hypoxia-reducing therapy: the hypoxia-activated prodrug TH-302 and vascular endothelial growth factor receptor 2 (VEGFR-2) blockade. The combination of both modalities normalized tumor vasculature, increased DNA damage and cell death, and delayed tumor growth. In contrast with prior cancer models, the combination did not alleviate overall tissue hypoxia or sensitize these KPC tumors to ICB therapy despite qualitative improvements to the CD8+ T cell response. Bulk tumor RNA sequencing, flow cytometry, and adoptive myeloid cell transfer suggested that treated tumor cells increased their capacity to recruit granulocytic myeloid-derived suppressor cells (G-MDSCs) through CCL9 secretion. Blockade of the CCL9/CCR1 axis could limit G-MDSC migration, and depletion of Ly6G-positive cells could sensitize tumors to the combination of TH-302, anti-VEGFR-2, and ICB. Together, these data suggest that pancreatic tumors modulate G-MDSC migration as an adaptive response to vascular normalization and that these immunosuppressive myeloid cells act in a setting of persistent hypoxia to maintain adaptive immune resistance.

Nitric Oxide‐Based Nanomedicines for Conquering TME Fortress: Say “NO” to Insufficient Tumor Treatment

AbstractAlmost all cancer treatments are significantly limited by the strong tumor microenvironment (TME) fortress formed by abnormal vasculature, dense extracellular matrix (ECM), multidrug resistance (MDR) system, and immune “cold” environment. In the huge efforts of dismantling the TME fortress, nitric oxide (NO)‐based nanomedicines are increasingly occupying a central position and have already been identified as super “strong polygonal warriors” to dismantle TME fortress for efficient cancer treatment, benefiting from NO's unique physicochemical properties and extremely fascinating biological effects. However, there is a paucity of systematic review to elaborate on the progress and fundamental mechanism of NO‐based nanomedicines in oncology from this aspect. Herein, the key characteristics of TME fortress and the potential of NO in reprogramming TME are delineated and highlighted. The evolution of NO donors and the advantages of NO‐based nanomedicines are discussed subsequently. Moreover, the latest progress of NO‐based nanomedicines for solid tumors is comprehensively reviewed, including normalizing tumor vasculature, overcoming ECM barrier, reversing MDR, and reactivating the immunosuppression TME. Lastly, the prospects, limitations, and future directions on NO‐based nanomedicines for TME manipulation are discussed to provide new insights into the construction of more applicable anticancer nanomedicines.

Repression of rRNA gene transcription by endothelial SPEN deficiency normalizes tumor vasculature via nucleolar stress.

Human cancers induce a chaotic, dysfunctional vasculature that promotes tumor growth and blunts most current therapies; however, the mechanisms underlying the induction of a dysfunctional vasculature have been unclear. Here, we show that split end (SPEN), a transcription repressor, coordinates rRNA synthesis in endothelial cells (ECs) and is required for physiological and tumor angiogenesis. SPEN deficiency attenuated EC proliferation and blunted retinal angiogenesis, which was attributed to p53 activation. Furthermore, SPEN knockdown activated p53 by upregulating noncoding promoter RNA (pRNA), which represses rRNA transcription and triggers p53-mediated nucleolar stress. In human cancer biopsies, a low endothelial SPEN level correlated with extended overall survival. In mice, endothelial SPEN deficiency compromised rRNA expression and repressed tumor growth and metastasis by normalizing tumor vessels, and this was abrogated by p53 haploinsufficiency. rRNA gene transcription is driven by RNA polymerase I (RNPI). We found that CX-5461, an RNPI inhibitor, recapitulated the effect of Spen ablation on tumor vessel normalization and combining CX-5461 with cisplatin substantially improved the efficacy of treating tumors in mice. Together, these results demonstrate that SPEN is required for angiogenesis by repressing pRNA to enable rRNA gene transcription and ribosomal biogenesis and that RNPI represents a target for tumor vessel normalization therapy of cancer.

Active molecule-based theranostic agents for tumor vasculature normalization and antitumor efficacy

Tumor vascular normalization has emerged as a promising strategy for synergistic therapy recently. Based on the strategy of “fluorescence turn on-controllable release”, a novel bifunctional candidate was constructed based on previous developed vascular normalization inducer QDAU5, which could self-assemble to form functional enzyme infrared QDAU5 nanoparticles (FEIRQ NPs). Subsequently, biological evaluation demonstrated that the FEIRQ NPs could induce ferroptosis, endoplasmic reticulum stress, and antigen preconditioning and maturation of dendritic cells and CD8+ T cells, leading to excellent antitumor efficacy in the absence of cytotoxic drugs. Additionally, FEIRQ NPs show high fluorescence intensity upon exposure to the β-galactosidase (β-Gal) enzyme expressed in ovarian cancer, enabling real-time monitoring of therapeutic effects. Overall, our findings suggest a prospering strategy to early diagnosis and efficient therapy for ovarian cancer without cytotoxicity.

Dose-Specific Intratumoral GM-CSF Modulates Breast Tumor Oxygenation and Antitumor Immunity.

GM-CSF has been employed as an adjuvant to cancer immunotherapy with mixed results based on dosage. We previously showed that GM-CSF regulated tumor angiogenesis by stimulating soluble vascular endothelial growth factor (VEGF) receptor-1 from monocytes/macrophages in a dose-dependent manner that neutralized free VEGF, and intratumoral injections of high-dose GM-CSF ablated blood vessels and worsened hypoxia in orthotopic polyoma middle T Ag (PyMT) triple-negative breast cancer (TNBC). In this study, we assessed both immunoregulatory and oxygen-regulatory components of low-dose versus high-dose GM-CSF to compare effects on tumor oxygen, vasculature, and antitumor immunity. We performed intratumoral injections of low-dose GM-CSF or saline controls for 3 wk in FVB/N PyMT TNBC. Low-dose GM-CSF uniquely reduced tumor hypoxia and normalized tumor vasculature by increasing NG2+ pericyte coverage on CD31+ endothelial cells. Priming of "cold," anti-PD1-resistant PyMT tumors with low-dose GM-CSF (hypoxia reduced) sensitized tumors to anti-PD1, whereas high-dose GM-CSF (hypoxia exacerbated) did not. Low-dose GM-CSF reduced hypoxic and inflammatory tumor-associated macrophage (TAM) transcriptional profiles; however, no phenotypic modulation of TAMs or tumor-infiltrating lymphocytes were observed by flow cytometry. In contrast, high-dose GM-CSF priming increased infiltration of TAMs lacking the MHC class IIhi phenotype or immunostimulatory marker expression, indicating an immunosuppressive phenotype under hypoxia. However, in anti-PD1 (programmed cell death 1)-susceptible BALB/c 4T1 tumors (considered hot versus PyMT), high-dose GM-CSF increased MHC class IIhi TAMs and immunostimulatory molecules, suggesting disparate effects of high-dose GM-CSF across PyMT versus 4T1 TNBC models. Our data demonstrate a (to our knowledge) novel role for low-dose GM-CSF in reducing tumor hypoxia for synergy with anti-PD1 and highlight why dosage and setting of GM-CSF in cancer immunotherapy regimens require careful consideration.

Novel miRNA-based drug CD5-2 reduces liver tumor growth in diethylnitrosamine-treated mice by normalizing tumor vasculature and altering immune infiltrate.

Liver cancers exhibit abnormal (leaky) vasculature, hypoxia and an immunosuppressive microenvironment. Normalization of tumor vasculature is an emerging approach to treat many cancers. Blockmir CD5-2 is a novel oligonucleotide-based inhibitor of the miR-27a interaction with VE-Cadherin, the endothelial-specific cadherin. The combination of a vasoactive medication with inhibition of immune checkpoints such as programmed cell death protein 1 (PD1) has been shown to be effective in treating liver cancer in humans. We aimed to study the effect of CD5-2 combined with checkpoint inhibition (using an antibody against PD1) on liver tumor growth, vasculature and immune infiltrate in the diethylnitrosamine (DEN)-induced liver tumor mouse model. We first analyzed human miR-27a and VE-Cadherin expression data from The Cancer Genome Atlas for hepatocellular carcinoma. CD5-2 and/or anti-PD1 antibody were given to the DEN-treated mice from age 7-months until harvest at age 9-months. Tumor and non-tumor liver tissues were analyzed using histology, immunohistochemistry, immunofluorescence and scanning electron microscopy. Human data showed high miR-27a and low VE-Cadherin were both significantly associated with poorer prognosis. Mice treated with CD5-2 plus anti-PD1 antibody had significantly smaller liver tumors (50% reduction) compared to mice treated with either agent alone, controls, or untreated mice. There was no difference in tumor number. Histologically, tumors in CD5-2-treated mice had less leaky vessels with higher VE-Cadherin expression and less tumor hypoxia compared to non-CD5-2-treated mice. Only tumors in the combination CD5-2 plus anti-PD1 antibody group exhibited a more favorable immune infiltrate (significantly higher CD3+ and CD8+ T cells and lower Ly6G+ neutrophils) compared to tumors from other groups. CD5-2 normalized tumor vasculature and reduced hypoxia in DEN-induced liver tumors. CD5-2 plus anti-PD1 antibody reduced liver tumor size possibly by altering the immune infiltrate to a more immunosupportive one.

Scutellarin suppresses the metastasis of triple-negative breast cancer via targeting TNFα/TNFR2-RUNX1-triggered G-CSF expression in endothelial cells

Triple-negative breast cancer (TNBC) is heterogeneous and aggressive, with high vascularity and frequent metastasis. We have already found natural flavonoid scutellarin (SC) suppressed spontaneous TNBC metastasis via normalizing tumor vasculature in vivo. In this study, supernatant from tumor necrosis factorα (TNFα)-treated human mammary microvascular endothelial cell (HMMEC) promoted cell migration and pseudopod formation in TNBC cells, but these phenomena were disappeared in SC-co-treated HMMEC. TNFα enhanced the expression of granulocyte colony-stimulating factor (G-CSF) and granulocyte–macrophage colony-stimulating factor (GM-CSF) in both HMMEC and human umbilical vein endothelial cell (HUVEC). G-CSF promoted TNBC migration and invasion in vitro, while G-CSF neutralization antibody and SC both inhibited TNBC metastasis in Balb/c mice. SC had no inhibition on the G-CSF-induced TNBC cell migration, but reduced G-CSF content in TNBC tumor tissues and TNFα-stimulated endothelial cells (ECs). SC restricted the nuclear translocation of runt-related transcription factor 1 (RUNX1) in TNBC tumor vessels and TNFα-treated ECs. RUNX1 was found to directly bind to the promoter of G-CSF in TNBC tumor vessels and regulated G-CSF expression. TNF receptor 2 (TNFR2) was crucial for regulating the TNFα-induced RUNX1 activation and G-CSF expression. Notably, SC hindered the interaction between TNFα and TNFR2 via binding to TNFR2. This work demonstrated that SC reduced TNBC metastasis by targeting TNFα/TNFR2-initiated RUNX1 activation and subsequent G-CSF production in TNBC-associated ECs.