Solid Tumor Models Research Articles

Abstract PR004: Second generation RNA Polymerase I inhibitor PMR-116 targets ribsomal RNA synthesis to potently treat a broad spectrum of malignancies

Abstract Purpose and rational for the study: The purpose of the study was to develop novel 2nd generation ribosomal RNA synthesis inhibitors for cancer treatment. Ribosome biogenesis (RiBi) is essential for cell growth and proliferation. Transcription of ribosomal RNA genes by Pol I is a critical step in RiBi and is tightly regulated by tumor suppressors and oncoproteins. Indeed, the ability of the potent oncoprotein, MYC, to drive RiBi is necessary for its oncogenic activity (Bywater et al., Cancer Cell, 2011). These data suggested that targeting RiBi, might be a promising strategy to treat malignancies, especially those driven by MYC. To test this, we developed the 1st small molecule inhibitor of Pol I transcription, CX-5461 (Drgyin et al., Cancer Research 2011). While CX-5461 has shown promising activity in pre-clinical studies (Bywater et al., Cancer Cell, 2011; Rebello et al., Clin Cancer Res., 2016; Hein et al., Blood, 2017) and in early Phase trials (Khot et al., Cancer Discovery, 2019; Hilton et al., Nat Commun. 2022) its mechanism of action remains controversial with evidence of off-target activity inducing DNA damage through inhibition of TOPO2a (Cameron et al., Biomedicines, 2024; Koh et al., Nature Genetics, 2024). Thus, to determine if selective inhibition of Pol I transcription in the absence of DNA damage can be used to therapeutical treat cancer in vivo, we developed a series of more selective 2nd generation Pol I inhibitors with our lead compound being PMR-116. Methods and summary of data: We demonstrate that PMR-116 is selective for inhibition of Pol I over Poll II transcription and functions by stalling the Pol I complex at the rDNA promoter. PMR-116, exhibits improved drug-like properties and pharmacokinetics compared to 1st generation CX-5461. As a single agent PMR-116 efficiently treats a range of pre-clinical models of hematologic and solid tumors including lymphoma, AML, hepatocellular carcinoma and prostate cancer. MYC expression positively correlates with sensitivity to PMR-116 in human cancer cell lines and high MYC tumors in vivo are exceptionally sensitive to PMR-116. In contrast to CX-5461, the therapeutic response to PMR-116 occurs in the absence of DNA damage suggesting that DNA damage is not an obligatory response to Pol I transcription inhibition but rather an off-target effect of the 1st generation drug. Small molecule drug combination screens in AML cells demonstrate that PMR-116 works synergistically to reduce cell viability with a range of drugs including carfilzomib and quisinostat used for treatment of hematologic malignancies. Conclusions: Our data establishes inhibition of RNA polymerase I as a bone fide therapeutic target for cancer therapy and demonstrated that PMR-116 is a promising new broad- spectrum anti-cancer drug particularly for those tumors driven by MYC, which are highly refractory to standard therapies. Based on these data we have launched a Phase I clinical trial of PMR-116 in patients with advanced solid tumors (CTRN12620001146987). Citation Format: Rita Ferreira, Katherine M. Hannan, Konstantin Panov, Thejanni Udumanne, Amee J George, Zaka Yuen, Perlita Poh, Eric Kusnadi, Alisee Huglo, Mitchell Lawrence, Mustapha Haddach, Denis Drygin, Luc Furic, Ross D Hannan, Nadine Hein. Second generation RNA Polymerase I inhibitor PMR-116 targets ribsomal RNA synthesis to potently treat a broad spectrum of malignancies [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr PR004.

Discovery of SZJK-0421: A Novel Potent, Low Toxicity, Selective Second Generation of CRM1 Inhibitor for the Treatment of Both Hematological and Solid Tumors.

Nuclear export factor chromosome region maintenance 1 (CRM1) mediated the transport of various growth-regulatory proteins and was frequently overexpressed in many hematologic and solid tumors. Selinexor (KPT-330) was the only approved CRM1 inhibitor, but the severe gastrointestinal and central nervous system toxicities limited its clinical application. In this manuscript, a series of novel second-generation CRM1 inhibitors were designed, in which SZJK-0421 was a more reversible inhibitor than KPT-330. The treatment of various tumor cells with SZJK-0421 significantly inhibited the function of CRM1. SZJK-0421 displayed good liver microsome stabilities and pharmacokinetic properties. Most importantly, SZJK-0421 reduced the direct damage to the gastrointestinal mucosa, and the brain plasma distribution ratio of SZJK-0421 was very low in Sprague-Dawley (SD) rats (3%), which avoided gastrointestinal reactions such as central nausea and vomiting caused by large permeability of blood-brain barrier. In addition, SZJK-0421 exhibited strong anticancer efficacy in xenograft models of both solid and hematological tumors.

Preclinical development of T cells engineered to express a T cell antigen coupler (TAC) targeting Claudin 18.2-positive solid tumors.

The T cell antigen coupler (TAC) is a chimeric receptor that facilitates tumor antigen-specific activation of T cells by co-opting the endogenous T cell receptor complex in the absence of tonic signaling. Previous data demonstrates that TAC affords T cells with the ability to induce durable and safe anti-tumor responses in preclinical models of hematological and solid tumors. Here, we describe the preclinical pharmacology and safety of an autologous Claudin 18.2 (CLDN18.2)-directed TAC T cell therapy, TAC01-CLDN18.2, in preparation for a Phase I/II clinical study in subjects with CLDN18.2-positive solid tumors. Following a screen of putative TAC constructs, the specificity, activity, and cytotoxicity of TAC T cells expressing the final CLDN18.2-TAC receptor were evaluated in vitro and in vivo using gastric, gastroesophageal, and pancreatic tumor models as well as human cells derived from normal tissues. CLDN18.2-specific activity and cytotoxicity of CLDN18.2-TAC T cells were observed in coculture with various 2D tumor cultures naturally expressing CLDN18.2 as well as tumor spheroids. These effects occurred in models with low antigen levels and was positively associated with increasing CLDN18.2 expression. CLDN18.2-TAC T cells effectively eradicated established tumor xenografts in mice in the absence of observed off-target or on-target/off-tumor effects, elicited durable efficacy in recursive killing and tumor rechallenge experiments, and remained unreactive in coculture with human cells representing vital organs. Thus, the data demonstrate that CLDN18.2-TAC T cells can induce a specific and long-lasting anti-tumor response in various CLDN18.2-positive solid tumor models without notable TAC-dependent toxicities, supporting the clinical development of TAC01-CLDN18.2.

Radiotherapy enhances the anti-tumor effect of CAR-NK cells for hepatocellular carcinoma

BackgroundChimeric antigen receptor (CAR)-NK cell therapy has shown remarkable clinical efficacy and safety in the treatment of hematological malignancies. However, this efficacy was limited in solid tumors owing to hostile tumor microenvironment (TME). Radiotherapy is commonly used for solid tumors and proved to improve the TME. Therefore, the combination with radiotherapy would be a potential strategy to improve therapeutic efficacy of CAR-NK cells for solid tumors.MethodsGlypican-3 (GPC3) was used as a target antigen of CAR-NK cell for hepatocellular carcinoma (HCC). To promote migration towards HCC, CXCR2-armed CAR-NK92 cells targeting GPC3 were first developed, and their cytotoxic and migration activities towards HCC cells were evaluated. Next, the effects of irradiation on the anti-tumor activity of CAR-NK92 cells were assessed in vitro and in HCC-bearing NCG mice. Lastly, to demonstrate the potential mechanism mediating the sensitized effect of irradiation on CAR-NK cells, the differential gene expression profiles induced by irradiation were analyzed and the expression of some important ligands for the NK-cell activating receptors were further determined by qRT-PCR and flow cytometry.ResultsIn this study, we developed CXCR2-armed GPC3-targeting CAR-NK92 cells that exhibited specific and potent killing activity against HCC cells and the enhanced migration towards HCC cells. Pretreating HCC cells with irradiation enhanced in vitro anti-HCC effect and migration activity of CXCR2-armed CAR-NK92 cells. We further found that only high-dose (8 Gy) but not low-dose (2 Gy) irradiation in one fraction could significantly enhanced in vivo anti-HCC activity of CXCR2-armed CAR-NK92 cells. Irradiation with 8 Gy significantly up-regulated the expression of NK cell-activating ligands on HCC cells.ConclusionsOur results indicate the evidence that irradiation could efficiently enhance the anti-tumor effect of CAR-NK cells in solid tumor model. The combination with radiotherapy would be an attractive strategy to improve therapeutic efficacy of CAR-NK cells for solid tumors.

A combination of lymphatic drug delivery of anti-CTLA-4 antibody and local radiotherapy for solid-tumor treatment.

The combination of radiotherapy and immunotherapy is a promising approach that has been shown in clinical trials to improve significantly survival and response rates compared with monotherapy against solid tumor. Since anti-CTLA-4 antibodies block immunosuppressive signals mainly in the lymph nodes (LNs), efficient drug delivery to the lymphatic system is desirable. However, the immune checkpoint inhibitors, especially anti-CTLA-4 are currently administered intravenously (i.v.), resulting in limited efficacy in controlling solid tumor and inhibiting metastases, and the method of administration has not been optimized. Here, we show that a combination of local radiotherapy and administration of anti-CTLA-4 antibodies using a lymphatic drug delivery system (LDDS) suppresses solid tumor and metastases. We compared the efficacy of LDDS-based immunotherapy or radioimmunotherapy with i.v. administration in a solid-tumor model created by subcutaneous inoculation into LN-swollen mice with osteosarcoma cells. Tumor-bearing mice were divided into various groups (no treatment, immunotherapy [i.v. or LDDS], radiotherapy, and radioimmunotherapy [i.v. or LDDS]) and were observed for 28 days. Immunotherapy was administered with a cumulative dose of 10 mg/kg of anti-CTLA-4 monoclonal antibody, and radiotherapy was administered with a cumulative 8 Gy of fractionated X-ray irradiation. For immunotherapy alone, LDDS provided slight tumor growth inhibition but did not inhibit distant metastasis. For radioimmunotherapy, however, tumor growth was delayed and distant metastasis was suppressed compared with radiotherapy alone. In particular, the LDDS group achieved a high tumor-suppressive effect with T cell-mediated immune activity, indicating the efficacy of LDDS in radioimmunotherapy.

CD28 Costimulation Augments CAR Signaling in NK Cells via the LCK/CD3ζ/ZAP70 Signaling Axis.

Multiple factors in the design of a chimeric antigen receptor (CAR) influence CAR T-cell activity, with costimulatory signals being a key component. Yet, the impact of costimulatory domains on the downstream signaling and subsequent functionality of CAR-engineered natural killer (NK) cells remains largely unexplored. Here, we evaluated the impact of various costimulatory domains on CAR-NK cell activity, using a CD70-targeting CAR. We found that CD28, a costimulatory molecule not inherently present in mature NK cells, significantly enhanced the antitumor efficacy and long-term cytotoxicity of CAR-NK cells both in vitro and in multiple xenograft models of hematologic and solid tumors. Mechanistically, we showed that CD28 linked to CD3ζ creates a platform that recruits critical kinases, such as lymphocyte-specific protein tyrosine kinase (LCK) and zeta-chain-associated protein kinase 70 (ZAP70), initiating a signaling cascade that enhances CAR-NK cell function. Our study provides insights into how CD28 costimulation enhances CAR-NK cell function and supports its incorporation in NK-based CARs for cancer immunotherapy. Significance: We demonstrated that incorporation of the T-cell-centric costimulatory molecule CD28, which is normally absent in mature natural killer (NK) cells, into the chimeric antigen receptor (CAR) construct recruits key kinases including lymphocyte-specific protein tyrosine kinase and zeta-chain-associated protein kinase 70 and results in enhanced CAR-NK cell persistence and sustained antitumor cytotoxicity.

Solid cancer-directed CAR T cell therapy that attacks both tumor and immunosuppressive cells via targeting PD-L1

Chimeric antigen receptor (CAR) T-cell therapy has encountered limited success in solid tumors. The lack of dependable antigens and the immunosuppressive tumor microenvironment (TME) are major challenges. Within the TME, tumor cells along with immunosuppressive cells employ an immune-evasion mechanism that upregulates programmed death ligand 1 (PD-L1) to deactivate effector T cells; this makes PD-L1 a reliable, universal target for solid tumors. We developed a novel PD-L1 CAR (MC9999) using our humanized anti-PD-L1 monoclonal antibody, designed to simultaneously target tumor and immunosuppressive cells. The antigen-specific antitumor effects of MC9999 CAR T-cells were observed consistently across four solid tumor models: breast cancer, lung cancer, melanoma, and glioblastoma multiforme (GBM). Notably, intravenous administration of MC9999 CAR T-cells eradicated intracranially established LN229 GBM tumors, suggesting penetration of the blood-brain barrier. The proof-of-concept data demonstrate the cytolytic effect of MC9999 CAR T-cells against immunosuppressive cells, including microglia HMC3 cells and M2 macrophages. Furthermore, MC9999 CAR T-cells elicited cytotoxicity against primary tumor-associated macrophages within GBM tumors. The concept of targeting both tumor and immunosuppressive cells with MC9999 was further validated using CAR T-cells derived from cancer patients. These findings establish MC9999 as a foundation for the development of effective CAR T-cell therapies against solid tumors.

254 (PB242): HMPL-500, a potent and selective EZH1/EZH2 dual inhibitor, demonstrates superior anti-tumor activity in preclinical models of hematological malignancies and solid tumors

254 (PB242): HMPL-500, a potent and selective EZH1/EZH2 dual inhibitor, demonstrates superior anti-tumor activity in preclinical models of hematological malignancies and solid tumors

Glypican-3-targeted macrophages delivering drug-loaded exosomes offer efficient cytotherapy in mouse models of solid tumours

Cytotherapy is a strategy to deliver modified cells to a diseased tissue, but targeting solid tumours remains challenging. Here we design macrophages, harbouring a surface glypican-3-targeting peptide and carrying a cargo to combat solid tumours. The anchored targeting peptide facilitates tumour cell recognition by the engineered macrophages, thus enhancing specific targeting and phagocytosis of tumour cells expressing glypican-3. These macrophages carry a cargo of the TLR7/TLR8 agonist R848 and INCB024360, a selective indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor, wrapped in C16-ceramide-fused outer membrane vesicles (OMV) of Escherichia coli origin (RILO). The OMVs facilitate internalization through caveolin-mediated endocytosis, and to maintain a suitable nanostructure, C16-ceramide induces membrane invagination and exosome generation, leading to the release of cargo-packed RILOs through exosomes. RILO-loaded macrophages exert therapeutic efficacy in mice bearing H22 hepatocellular carcinomas, which express high levels of glypican-3. Overall, we lay down the proof of principle for a cytotherapeutic strategy to target solid tumours and could complement conventional treatment.

Preclinical Evaluation of STI-8811, a Novel Antibody-Drug Conjugate Targeting BCMA for the Treatment of Multiple Myeloma.

Treatment for patients with multiple myeloma has experienced rapid development and improvement in recent years; however, patients continue to experience relapse, and multiple myeloma remains largely incurable. B-cell maturation antigen (BCMA) has been widely recognized as a promising target for treatment of multiple myeloma due to its exclusive expression in B-cell linage cells and its critical role in the growth and survival of malignant plasma cells. Here, we introduce STI-8811, a BCMA-targeting antibody-drug conjugate (ADC) linked to an auristatin-derived duostatin payload via an enzymatically cleavable peptide linker, using our proprietary C-lock technology. STI-8811 exhibits target-specific binding activity and rapid internalization, leading to G2/M cell-cycle arrest, caspase 3/7 activation, and apoptosis in BCMA-expressing tumor cells in vitro. Soluble BCMA (sBCMA) is shed by multiple myeloma cells into the blood and increases with disease progression, competing for ADC binding and reducing its efficacy. We report enhanced cytotoxic activity in the presence of high levels of sBCMA compared with a belantamab mafodotin biosimilar (J6M0-mcMMAF). STI-8811 demonstrated greater in vivo activity than J6M0-mcMMAF in solid and disseminated multiple myeloma models, including tumor models with low BCMA expression and/or in large solid tumors representing soft-tissue plasmacytomas. In cynomolgus monkeys, STI-8811 was well tolerated, with toxicities consistent with other BCMA-targeting ADCs with auristatin payloads in clinical studies. STI-8811 has the potential to outperform current clinical candidates with lower toxicity and higher activity under conditions found in patients with advanced disease. Significance: STI-8811 is a BCMA-targeting ADC carrying a potent auristatin derivative. We report unique binding properties which maintain potent cytotoxic activity under sBCMA-high conditions that hinder the clinical efficacy of current BCMA-targeting ADC candidates. Beyond disseminated models of multiple myeloma, we observed efficacy in solid tumor models of plasmacytomas with low and heterogenous BCMA expressions at a magnitude and duration of response exceeding that of clinical comparators.

In Vitro Cytotoxic Potential and In Vivo Antitumor Effects of NOS/PDK-Inhibitor T1084.

Previously, we showed the antitumor activity of the new NOS/PDK inhibitor T1084 (1-isobutanoyl-2-isopropylisothiourea dichloroacetate). The present study included an assessment of in vitro cytotoxicity against human malignant and normal cells according to the MTT-test and in vivo antitumor effects in solid tumor models in comparison with precursor compounds T1023 (NOS inhibitor; 1-isobutanoyl-2-isopropylisothiourea hydrobromide) and Na-DCA (PDK inhibitor; sodium dichloroacetate), using morphological, histological, and immunohistochemical methods. The effects of T1084 and T1023 on the in vitro survival of normal (MRC-5) and most malignant cells (A375, MFC-7, K562, OAW42, and PC-3) were similar and quantitatively equal. At the same time, melanoma A375 cells showed 2-2.5 times higher sensitivity (IC50: 0.39-0.41 mM) to the cytotoxicity of T1023 and T1084 than other cells. And only HeLa cells showed significantly higher sensitivity to the cytotoxicity of T1084 compared to T1023 (IC50: 0.54 ± 0.03 and 0.81 ± 0.02 mM). Comparative studies of the in vivo antitumor effects of Na-DCA, T1023, and T1084 on CC-5 cervical cancer and B-16 melanoma in mice were conducted with subchronic daily i.p. administration of these agents at an equimolar dose of 0.22 mmol/kg (33.6, 60.0, and 70.7 mg/kg, respectively). Cervical cancer CC-5 fairly quickly evaded the effects of both Na-DCA and T1023. So, from the end of the first week of Na-DCA or T1023 treatment, the tumor growth inhibition (TGI) began to decrease from 40% to an insignificant level by the end of the observation. In contrast, in two independent experiments, CC-5 showed consistently high sensitivity to the action of T1084: a significant antitumor effect with high TGI (43-58%) was registered throughout the observation, without any signs of neoplasia adaptation. The effect of precursor compounds on melanoma B-16 was either minimal (for Na-DCA) or moderate (for T1023) with TGI only 33%, which subsequently decreased by the end of the experiment. In contrast, the effect of T1084 on B-16 was qualitatively more pronounced and steadily increasing; it was accompanied by a 3-fold expansion of necrosis and dystrophy areas, a decrease in proliferation, and increased apoptosis of tumor cells. Morphologically, the T1084 effect was 2-fold superior to the effects of T1023-the TGI index reached 59-62%. This study suggests that the antitumor effects of T1084 develop through the interaction of NOS-dependent and PDK-dependent pathophysiological effects of this NOS/PDK inhibitor. The NOS inhibitory activity of T1084 exerts an anti-angiogenic effect on neoplasia. At the same time, the PDK inhibitory activity of T1084 enhances the cytotoxicity of induced intratumoral hypoxia and suppresses the development of neoplasia adaptation to anti-angiogenic stress. Such properties allow T1084 to overcome tumor resistance and realize a stable synergistic antitumor effect.

Pharmacologic LDH inhibition redirects intratumoral glucose uptake and improves antitumor immunity in solid tumor models.

Tumor reliance on glycolysis is a hallmark of cancer. Immunotherapy is more effective in controlling glycolysis-low tumors lacking lactate dehydrogenase (LDH) due to reduced tumor lactate efflux and enhanced glucose availability within the tumor microenvironment (TME). LDH inhibitors (LDHi) reduce glucose uptake and tumor growth in preclinical models, but their impact on tumor-infiltrating T cells is not fully elucidated. Tumor cells have higher basal LDH expression and glycolysis levels compared with infiltrating T cells, creating a therapeutic opportunity for tumor-specific targeting of glycolysis. We demonstrate that LDHi treatment (a) decreases tumor cell glucose uptake, expression of the glucose transporter GLUT1, and tumor cell proliferation while (b) increasing glucose uptake, GLUT1 expression, and proliferation of tumor-infiltrating T cells. Accordingly, increasing glucose availability in the microenvironment via LDH inhibition leads to improved tumor-killing T cell function and impaired Treg immunosuppressive activity in vitro. Moreover, combining LDH inhibition with immune checkpoint blockade therapy effectively controls murine melanoma and colon cancer progression by promoting effector T cell infiltration and activation while destabilizing Tregs. Our results establish LDH inhibition as an effective strategy for rebalancing glucose availability for T cells within the TME, which can enhance T cell function and antitumor immunity.

Validation of Non-Small Cell Lung Cancer Clinical Insights Using a Generalized Oncology Natural Language Processing Model.

Limited studies have used natural language processing (NLP) in the context of non-small cell lung cancer (NSCLC). This study aimed to validate the application of an NLP model to an NSCLC cohort by extracting NSCLC concepts from free-text medical notes and converting them to structured, interpretable data. Patients with a lung neoplasm, NSCLC histology, and treatment information in their notes were selected from a repository of over 27 million patients. From these, 200 were randomly selected for this study with the longest and the most recent note included for each patient. An NLP model developed and validated on a large solid and blood cancer oncology cohort was applied to this NSCLC cohort. Two certified tumor registrars and a curator abstracted concepts from the notes: neoplasm, histology, stage, TNM values, and metastasis sites. This manually abstracted gold standard was compared with the NLP model output. Precision and recall scores were calculated. The NLP model extracted the NSCLC concepts with excellent precision and recall with the following scores, respectively: Lung neoplasm 100% and 100%, NSCLC histology 99% and 88%, histology correctly linked to neoplasm 98% and 79%, stage value 98.8% and 92%, stage TNM value 93% and 98%, and metastasis site 97% and 89%. High precision is related to a low number of false positives, and therefore, extracted concepts are likely accurate. High recall indicates that the model captured most of the desired concepts. This study validates that Optum's oncology NLP model has high precision and recall with clinical real-world data and is a reliable model to support research studies and clinical trials. This validation study shows that our nonspecific solid tumor and blood cancer oncology model is generalizable to successfully extract clinical information from specific cancer cohorts.

Therapeutic Efficacy of IL7/CCL19-Expressing CAR-T Cells in Intractable Solid Tumor Models of Glioblastoma and Pancreatic Cancer.

Despite the clinical development of CAR T-cell therapy, its efficacy in solid cancers has yet to be established. This study explored the therapeutic potential and immunologic mechanisms of IL7/CCL19-producing CAR-T therapy in preclinical solid cancer models of glioblastoma and pancreatic cancer. We found that IL7/CCL19-producing CAR-T cells generated from the patient's PBMC showed potent therapeutic effects against the solid cancer model established by inoculating organoids from the autologous tumor tissue.

BRD-810 is a highly selective MCL1 inhibitor with optimized in vivo clearance and robust efficacy in solid and hematological tumor models

The MCL1 gene is frequently amplified in cancer and codes for the antiapoptotic protein myeloid cell leukemia 1 (MCL1), which confers resistance to the current standard of care. Therefore, MCL1 is an attractive anticancer target. Here we describe BRD-810 as a potent and selective MCL1 inhibitor and its key design principle of rapid systemic clearance to potentially minimize area under the curve-driven toxicities associated with MCL1 inhibition. BRD-810 induced rapid cell killing within 4 h in vitro but, in the same 4-h window, had no impact on cell viability or troponin I release in human induced pluripotent stem cell-derived cardiomyocytes, even at suprapharmacologic concentrations. In vivo BRD-810 induced efficacy in xenograft hematological and solid tumor models despite the short residence time of BRD-810 in plasma. In totality, our data support the hypothesis that short-term inhibition of MCL1 with BRD-810 can induce apoptosis in tumor cells while maintaining an acceptable safety profile. We, therefore, intend to advance BRD-810 to clinical trials.

Renal tumor segmentation, visualization, and segmentation confidence using ensembles of neural networks in patients undergoing surgical resection.

To develop an automatic segmentation model for solid renal tumors on contrast-enhanced CTs and to visualize segmentation with associated confidence to promote clinical applicability. The training dataset included solid renal tumor patients from two tertiary centers undergoing surgical resection and receiving CT in the corticomedullary or nephrogenic contrast media (CM) phase. Manual tumor segmentation was performed on all axial CT slices serving as reference standard for automatic segmentations. Independent testing was performed on the publicly available KiTS 2019 dataset. Ensembles of neural networks (ENN, DeepLabV3) were used for automatic renal tumor segmentation, and their performance was quantified with DICE score. ENN average foreground entropy measured segmentation confidence (binary: successful segmentation with DICE score > 0.8 versus inadequate segmentation ≤ 0.8). N = 639/n = 210 patients were included in the training and independent test dataset. Datasets were comparable regarding age and sex (p > 0.05), while renal tumors in the training dataset were larger and more frequently benign (p < 0.01). In the internal test dataset, the ENN model yielded a median DICE score = 0.84 (IQR: 0.62-0.97, corticomedullary) and 0.86 (IQR: 0.77-0.96, nephrogenic CM phase), and the segmentation confidence an AUC = 0.89 (sensitivity = 0.86; specificity = 0.77). In the independent test dataset, the ENN model achieved a median DICE score = 0.84 (IQR: 0.71-0.97, corticomedullary CM phase); and segmentation confidence an accuracy = 0.84 (sensitivity = 0.86 and specificity = 0.81). ENN segmentations were visualized with color-coded voxelwise tumor probabilities and thresholds superimposed on clinical CT images. ENN-based renal tumor segmentation robustly performs in external test data and might aid in renal tumor classification and treatment planning. Ensembles of neural networks (ENN) models could automatically segment renal tumors on routine CTs, enabling and standardizing downstream image analyses and treatment planning. Providing confidence measures and segmentation overlays on images can lower the threshold for clinical ENN implementation. Ensembles of neural networks (ENN) segmentation is visualized by color-coded voxelwise tumor probabilities and thresholds. ENN provided a high segmentation accuracy in internal testing and in an independent external test dataset. ENN models provide measures of segmentation confidence which can robustly discriminate between successful and inadequate segmentations.

Modified C-type natriuretic peptide normalizes tumor vasculature, reinvigorates antitumor immunity, and improves solid tumor therapies.

Deficit of oxygen and nutrients in the tumor microenvironment (TME) triggers abnormal angiogenesis that produces dysfunctional and leaky blood vessels, which fail to adequately perfuse tumor tissues. Resulting hypoxia, exacerbation of metabolic disturbances, and generation of an immunosuppressive TME undermine the efficacy of anticancer therapies. Use of carefully scheduled angiogenesis inhibitors has been suggested to overcome these problems and normalize the TME. Here, we propose an alternative agonist-based normalization approach using a derivative of the C-type natriuretic peptide (dCNP). Multiple gene expression signatures in tumor tissues were affected in mice treated with dCNP. In several mouse orthotopic and subcutaneous solid tumor models including colon and pancreatic adenocarcinomas, this well-tolerated agent stimulated formation of highly functional tumor blood vessels to reduce hypoxia. Administration of dCNP also inhibited stromagenesis and remodeling of the extracellular matrix and decreased tumor interstitial fluid pressure. In addition, treatment with dCNP reinvigorated the antitumor immune responses. Administration of dCNP decelerated growth of primary mouse tumors and suppressed their metastases. Moreover, inclusion of dCNP into the chemo-, radio-, or immune-therapeutic regimens increased their efficacy against solid tumors in immunocompetent mice. These results demonstrate the proof of principle for using vasculature normalizing agonists to improve therapies against solid tumors and characterize dCNP as the first in class among such agents.

BP1003 Decreases STAT3 Expression and Its Pro-Tumorigenic Functions in Solid Tumors and the Tumor Microenvironment.

Overexpression and aberrant activation of signal transducer and activator of transcription 3 (STAT3) contribute to tumorigenesis, drug resistance, and tumor-immune evasion, making it a potential cancer therapeutic target. BP1003 is a neutral liposome incorporated with a nuclease-resistant P-ethoxy antisense oligodeoxynucleotide (ASO) targeting the STAT3 mRNA. Its unique design enhances BP1003 stability, cellular uptake, and target affinity. BP1003 efficiently reduces STAT3 expression and enhances the sensitivity of breast cancer cells (HER2+, triple negative) and ovarian cancer cells (late stage, invasive ovarian cancer) to paclitaxel and 5-fluorouracil (5-FU) in both 2D and 3D cell cultures. Similarly, ex vivo and in vivo patient-derived models of pancreatic ductal adenocarcinoma (PDAC) show reduced tissue viability and tumor volume with BP1003 and gemcitabine combination treatments. In addition to directly affecting tumor cells, BP1003 can modulate the tumor microenvironment. Unlike M1 differentiation, monocyte differentiation into anti-inflammatory M2 macrophages is suppressed by BP1003, indicating its potential contribution to immunotherapy. The broad anti-tumor effect of BP1003 in numerous preclinical solid tumor models, such as breast, ovarian, and pancreatic cancer models shown in this work, makes it a promising cancer therapeutic.

Piperine enhances doxorubicin sensitivity in triple-negative breast cancer by targeting the PI3K/Akt/mTOR pathway and cancer stem cells

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that lacks an actionable target with limited treatment options beyond conventional chemotherapy. Therapeutic failure is often encountered due to inherent or acquired resistance to chemotherapy. Previous studies implicated PI3K/Akt/mTOR signaling pathway in cancer stem cells (CSCs) enrichment and hence chemoresistance. The present study aimed at investigating the potential effect of piperine (PIP), an amide alkaloid isolated from Piper nigrum, on enhancing the sensitivity of TNBC cells to doxorubicin (DOX) in vitro on MDA-MB-231 cell line and in vivo in an animal model of Ehrlich ascites carcinoma solid tumor. Results showed a synergistic interaction between DOX and PIP on MDA-MB-231 cells. In addition, the combination elicited enhanced suppression of PI3K/Akt/mTOR signaling that paralleled an upregulation in this pathway’s negative regulator, PTEN, along with a curtailment in the levels of the CSCs surrogate marker, aldehyde dehydrogenase-1 (ALDH-1). Meanwhile, in vivo investigations demonstrated the potential of the combination regimen to enhance necrosis while downregulating PTEN and curbing PI3K levels as well as p-Akt, mTOR, and ALDH-1 immunoreactivities. Notably, the combination failed to change cleaved poly-ADP ribose polymerase levels suggesting a pro-necrotic rather than pro-apoptotic mechanism. Overall, these findings suggest a potential role of PIP in decreasing the resistance to DOX in vitro and in vivo, likely by interfering with the PI3K/Akt/mTOR pathway and CSCs.

Discovery of a Myeloid Cell Leukemia 1 (Mcl-1) Inhibitor That Demonstrates Potent In Vivo Activities in Mouse Models of Hematological and Solid Tumors.

Myeloid cell leukemia 1 (Mcl-1) is a key regulator of the intrinsic apoptosis pathway. Overexpression of Mcl-1 is correlated with high tumor grade, poor survival, and both intrinsic and acquired resistance to cancer therapies. Herein, we disclose the structure-guided design of a small molecule Mcl-1 inhibitor, compound 26, that binds to Mcl-1 with subnanomolar affinity, inhibits growth in cell culture assays, and possesses low clearance in mouse and dog pharmacokinetic (PK) experiments. Evaluation of 26 as a single agent in Mcl-1 sensitive hematological and solid tumor xenograft models resulted in regressions. Co-treatment of Mcl-1-sensitive and Mcl-1 insensitive lung cancer derived xenografts with 26 and docetaxel or topotecan, respectively, resulted in an enhanced tumor response. These findings support the premise that pro-apoptotic priming of tumor cells by other therapies in combination with Mcl-1 inhibition may significantly expand the subset of cancers in which Mcl-1 inhibitors may prove beneficial.