Substantial Tumor Growth Inhibition Research Articles

Neuronatin Promotes the Progression of Non-small Cell Lung Cancer by Activating the NF-κB Signaling.

Understanding the regulatory mechanisms involving neuronatin (NNAT) in non-small cell lung cancer (NSCLC) is an ongoing challenge. This study aimed to elucidate the impact of NNAT knockdown on NSCLC by employing both in vitro and in vivo approaches. To investigate the role of NNAT, its expression was silenced in NSCLC cell lines A549 and H226. Subsequently, various parameters, including cell proliferation, invasion, migration, and apoptosis, were assessed. Additionally, cell-derived xenograft models were established to evaluate the effect of NNAT knockdown on tumor growth. The expression of key molecules, including cyclin D1, B-cell leukemia/lymphoma 2 (Bcl-2), p65, matrix metalloproteinase (MMP) 2, and nerve growth factor (NGF) were examined both in vitro and in vivo. Nerve fiber density within tumor tissues was analyzed using silver staining. Upon NNAT knockdown, a remarkable reduction in NSCLC cell proliferation, invasion, and migration was observed, accompanied by elevated levels of apoptosis. Furthermore, the expression of cyclin D1, Bcl-2, MMP2, and phosphorylated p65 (p-p65) showed significant downregulation. In vivo, NNAT knockdown led to substantial inhibition of tumor growth and a concurrent decrease in cyclinD1, Bcl-2, MMP2, and p-p65 expression within tumor tissues. Importantly, NNAT knockdown also led to a decrease in nerve fiber density and downregulation of NGF expression within the xenograft tumor tissues. Collectively, these findings suggest that neuronatin plays a pivotal role in driving NSCLC progression, potentially through the activation of the nuclear factor-kappa B signaling cascade. Additionally, neuronatin may contribute to the modulation of tumor microenvironment innervation in NSCLC. Targeting neuronatin inhibition emerges as a promising strategy for potential anti-NSCLC therapeutic intervention.

The anti-tumor efficacy of a recombinant oncolytic herpes simplex virus mediated CRISPR/Cas9 delivery targeting in HPV16-positive cervical cancer

Cervical cancer, often driven by high-risk human papillomavirus (HPV) infections such as HPV16 or HPV18, remains a leading cause of cancer-related deaths. HPV16, found in about 90% of cervical cancer patients, harbors key oncogenic related genes (E6, E7, E2, E5) and an upstream regulatory region (URR) that contribute to cancer progression. This study introduces a novel approach using a recombinant oncolytic herpes simplex virus type 1 (HSV-1) named SONC103, armed with a CRISPR/Cas9 gene editing system. The aim was to target and disrupt integrated HPV16 genes in cervical cancer cells. Results demonstrated SONC103's capability to specifically and effectively knock down HPV16 oncogenes, thereby reducing cell proliferation and promoting apoptosis. Analyses further revealed loss of HPV16 DNA probes in infected cells' chromosomes, significant regulation of cellular processes related to tumor apoptosis, and downregulation of E6/E7 oncoproteins while increasing tumor suppressor proteins P53 and pRB. Notably, SONC103 exhibited substantial inhibition of tumor growth in a murine xenograft cervical cancer model. This study showcases the potential of the recombinant oncolytic HSV-1 virus (SONC103) in combating HPV16-positive cervical cancer by targeting oncogenes and facilitating oncolysis.

Intraperitoneal administration of adeno-associated virus encoding microRNA-29b for the treatment of peritoneal metastasis.

This study explores a novel therapeutic approach for peritoneal metastasis (PM) using AAV-mediated delivery of tumor suppressor microRNA-29b (miR-29b) to peritoneal mesothelial cells (PMC). AAV serotypes 2 and DJ demonstrate high transduction efficiency for human and murine PMC, respectively. In vitro analysis indicates that AAV vectors encoding miR-29b precursor successfully elevate miR-29b expression in PMC and their secreted small extracellular vesicle (sEV), thereby inhibiting mesothelial mesenchymal transition and reducing subsequent attachment of tumor cells. A single intraperitoneal (IP) administration of AAV-DJ-miR-29b demonstrates robust and sustained transgene expression, suppressing peritoneal fibrosis and inhibiting the development of PM from gastric and pancreatic cancers. Additionally, AAV-DJ-miR-29b enhances the efficacy of IP chemotherapy using paclitaxel, restraining the growth of established PM. While conventional gene therapy for cancer encounters challenges targeting tumor cells directly but delivering miRNA to the tumor stroma offers a straightforward and efficient means of altering the microenvironment, leading to substantial inhibition of tumor growth. AAV-mediated miR-29b delivery to peritoneum via IP route presents a simple, minimally invasive, and promising therapeutic strategy for refractory PM.

In situ reprogramming of tumor-associated macrophages enhances cancer immunotherapy

In situ reprogramming of tumor associated macrophages (TAMs) to resurge their phagocytic ability holds great potential in cancer treatment. However, most of currently existing TAMs-reshaping approaches fail to effectively reprogram TAMs due to low efficiency, poor specificity, and potential immune side effects. Herein, we report a strategy called molecularly imprinted lysosomal nanodegrader (MILND) for resurging the phagocytosis of macrophages and reversing the "don't eat me" CD47-SIRPα signal via degrading SIRPα in lysosomes. The MILND, which was rationally engineered by controllable molecular imprinting using the N-terminal epitope of SIRPα as template, could specifically bind SIPRα on TAMs. Upon being engulfed by TAMs via endocytosis, the MILND-SIRPα complex was transferred to lysosomes for degradation. The degradation of SIRPα induced a cascade reaction of the downstream PI3K signaling pathway to resurging the phagocytic and recognition capability of TAMs towards cancer cells. Ultimately, MILND resulted in a subsequent series of anti-tumor effects. Benefiting from this, MILND effectively sensitized the immune microenvironment and amplified CD8+ T cell responses, leading to substantial tumor growth inhibition in tumor-bearing mouse model. Thus, this work provides an efficient and versatile immunomodulatory strategy for enhanced antitumor immunotherapy.

Identification of Anticancer Peptides from the Genome of Candida albicans: in Silico Screening, in Vitro and in Vivo Validations.

Anticancer peptides (ACPs) are promising future therapeutics, but their experimental discovery remains time-consuming and costly. To accelerate the discovery process, we propose a computational screening workflow to identify, filter, and prioritize peptide sequences based on predicted class probability, antitumor activity, and toxicity. The workflow was applied to identify novel ACPs with potent activity against colorectal cancer from the genome sequences of Candida albicans. As a result, four candidates were identified and validated in the HCT116 colon cancer cell line. Among them, PCa1 and PCa2 emerged as the most potent, displaying IC50 values of 3.75 and 56.06 μM, respectively, and demonstrating a 4-fold selectivity for cancer cells over normal cells. In the colon xenograft nude mice model, the administration of both peptides resulted in substantial inhibition of tumor growth without causing significant adverse effects. In conclusion, this work not only contributes a proven computational workflow for ACP discovery but also introduces two peptides, PCa1 and PCa2, as promising candidates poised for further development as targeted therapies for colon cancer. The method as a web service is available at https://app.cbbio.online/acpep/home and the source code at https://github.com/cartercheong/AcPEP_classification.git.

Identification of 6-Anilino Imidazo[4,5-c]pyridin-2-ones as Selective DNA-Dependent Protein Kinase Inhibitors and Their Application as Radiosensitizers.

The dominant role of non-homologous end-joining in the repair of radiation-induced double-strand breaks identifies DNA-dependent protein kinase (DNA-PK) as an excellent target for the development of radiosensitizers. We report the discovery of a new class of imidazo[4,5-c]pyridine-2-one DNA-PK inhibitors. Structure-activity studies culminated in the identification of 78 as a nM DNA-PK inhibitor with excellent selectivity for DNA-PK compared to related phosphoinositide 3-kinase (PI3K) and PI3K-like kinase (PIKK) families and the broader kinome, and displayed DNA-PK-dependent radiosensitization of HAP1 cells. Compound 78 demonstrated robust radiosensitization of a broad range of cancer cells in vitro, displayed high oral bioavailability, and sensitized colorectal carcinoma (HCT116/54C) and head and neck squamous cell carcinoma (UT-SCC-74B) tumor xenografts to radiation. Compound 78 also provided substantial tumor growth inhibition of HCT116/54C tumor xenografts in combination with radiation. Compound 78 represents a new, potent, and selective class of DNA-PK inhibitors with significant potential as radiosensitizers for cancer treatment.

177Lu Anti-Angiogenic Radioimmunotherapy Targeting ATP Synthase in Gastric Cancer Model.

This study investigated a novel radioimmunotherapy strategy for targeting tumor angiogenesis. We developed a radiopharmaceutical complex by labeling an anti-adenosine triphosphate synthase (ATPS) monoclonal antibody (mAb) with the radioisotope 177Lu using DOTA as a chelating agent. 177Lu-DOTA-ATPS mAb demonstrated high labeling efficiency (99.0%) and stability in serum. MKN-45 cancer cells exhibited the highest cellular uptake, which could be specifically blocked by unlabeled ATPS mAb. In mice, 177Lu-DOTA-ATPS mAb accumulated significantly in tumors, with a tumor uptake of 16.0 ± 1.5%ID/g on day 7. 177Lu-DOTA-ATPS mAb treatment significantly reduced the viability of MKN-45 cells in a dose-dependent manner. In a xenograft tumor model, this radioimmunotherapy strategy led to substantial tumor growth inhibition (82.8%). Furthermore, combining 177Lu-DOTA-ATPS mAb with sunitinib, an anti-angiogenic drug, enhanced the therapeutic efficacy of sunitinib in the mouse model. Our study successfully developed 177Lu-DOTA-ATPS mAb, a radioimmunotherapy agent targeting tumor blood vessels. This approach demonstrates significant promise for inhibiting tumor growth, both as a single therapy and in combination with other anti-cancer drugs.

Lipo/TK-CDN/TPP/Y6 nanoparticles inhibit cutaneous melanoma formation

Stimulation of the innate immune stimulator of interferon genes (STING) pathway has been shown to boost anti-tumour immunity. Nevertheless, the systemic delivery of STING agonists to the tumour presents challenges. Therefore, we designed a cyclic dinucleotide (CDN)-based drug delivery system (DDS) combined photothermal therapy (PTT)/photodynamic therapy (PDT)/immunotherapy for cutaneous melanoma. We coencapsulated a reactive oxygen species (ROS)-responsive prodrug thioketone-linked CDN (TK-CDN), and photoresponsive agents chlorin E6 (Y6) within mitochondria-targeting reagent triphenylphosphonium (TPP)-modified liposomes (Lipo/TK-CDN/TPP/Y6). Lipo/TK-CDN/TPP/Y6 exhibited a photothermal effect similar to Y6, along with a superior cellular uptake rate. Upon endocytosis by B16F10 cells, Lipo/TK-CDN/TPP/Y6 generated large amounts of ROS under laser irradiation for PDT. Mice bearing B16F10 tumours were intravenously injected with Lipo/TK-CDN/TPP/Y6 and exposed to irradiation, resulting in a substantial inhibition of tumour growth. Exploration of the mechanism of anti-tumour action showed that Lipo/TK-CDN/TPP/Y6 had a stronger stimulation of STING activation and anti-tumour immune cell infiltration compared to other groups. Hence, the Lipo/TK-CDN/TPP/Y6 nanoparticles offer great potential as a DDS for targeted and on-demand drug release at tumour sites. These nanoparticles exhibit promise as a candidate for precise and controllable combination therapy in the treatment of tumours.

Effects of Glutamine Synthetase on Neovascularization in Glioma: In Vivo MR Vessel Size Imaging and Histology.

Glutamine Synthetase (GS) could induce vascular sprouting through the improvement of endothelial cell migration in inflammatory diseases. MR vessel-size imaging has been proposed as a valuable approach for visualizing the underlying angiogenic processes in the brain. This study aims to investigate the role of GS in the neovascularization of gliomas through the utilization of MR vessel-size imaging and histopathological techniques. In this exploratory animal study, we randomly divided the C6 glioma rat models into a control group and an L-methionine sulfoximine (MSO) treatment group. Daily intraperitoneal injections were administered for three consecutive days, starting from day 10 following the implantation of C6 glioma cells in rats. Subsequently, MR vessel size imaging was conducted using a BRUKER 7 T/200 mm MRI scanner, and the MRI results were validated through histopathological examination. A significant decrease in microvessel density was observed in both the tumor periphery and center areas in the MSO treatment group compared to that in the control group. The mean vessel diameter (mVD) and vessel size index (VSI) did not exhibit significant changes compared to the control group. Moreover, the staining intensity of platelet endothelial cell adhesion molecule-1 (CD31) and GS in the tumor periphery was significantly decreased in the MSO treatment group. Additionally, the MSO treatment demonstrated a substantial inhibition of tumor growth. GS inhibitors significantly reduced angiogenesis in the periphery area of C6 glioma, exerting an inhibitory effect on tumor progression. Thus, GS inhibitors could be potential therapeutic agents for treating glioma. Additionally, in vivo MR vessel size imaging detects changes in vascularrelated parameters after tumor treatment, making it a promising method for detecting neovascularization in glioma.</p>.

Abstract 1858: Discovery of AT86474, a highly efficacious anti-ROR1 ADC utilizing a proprietary payload

Abstract ROR1 is a pseudo kinase that is involved in the non-canonical Wnt signaling pathway and is highly expressed during early embryonic development. In adult tissues, ROR1 is expressed at very low levels but its increased expression is observed in hematological cancers and a broad range of solid tumors. AT86474 is a highly homogeneous antibody drug conjugate incorporating AxcynCYSTM technology that allows reproducible site-specific conjugation with DAR4 composition greater than 97%. AT86474 utilizes a proprietary payload derived from an FDA approved drug that was optimized in-house for increased potency and with altered PK properties to limit systemic exposure. In vitro, the payload displays broad sub-nanomolar activity across multiple cancer cell lines, including those resistant to paclitaxel, DM1, MMAE and DXd. The payload is conjugated via an enzyme-cleavable linker optimized for solubility, stability, and high drug to antibody ratios. AT86474 uses a humanized and optimized monoclonal antibody that demonstrates selective binding to ROR1-positive cells and subsequent internalization, sub-nanomolar potency in vitro and strong bystander effects. AT86474 was evaluated in a preclinical CDX mouse model of ovarian cancer, where substantial tumor growth inhibition was observed with two weekly doses at as low as 1 mg/kg. As ROR1 over-expression is also observed in many solid tumors, such as pancreatic, gastric, breast and lung cancers, the use of AT86474 can be expanded to benefit a large patient population. Citation Format: Ban Xiong Tan, Xi Yun Zhang, You Xue Wu, Yin Wen Cheng, Shao Jun Liu, Ping Du, Chen Zhong, Bin Zou. Discovery of AT86474, a highly efficacious anti-ROR1 ADC utilizing a proprietary payload [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 1858.

Abstract A016: NXP800, a novel, small molecule GCN2 kinase activator, demonstrates potent single-agent activity in ARID1A and ARID1B-deficient endometrial cancer xenograft models

Abstract Background: NXP800 is a clinical stage, antineoplastic, oral, small molecule GCN2 kinase activator that was discovered in a phenotypic screen for inhibitors of the heat shock factor 1-regulated stress response. In a panel of human carcinoma cell lines NXP800 induced the expression of genes associated with activation of the integrated stress response and demonstrated robust antiproliferative activity, particularly in ARID1a-mutated ovarian carcinoma cells lines. In ARID1a-mutated ovarian carcinoma xenografts, treatment with NXP800 resulted in substantial tumor growth inhibition and tumor regression. NXP800 is currently being investigated in a Phase 1b clinical trial in patients with ARID1a-mutated ovarian carcinoma. Here we describe an in vivo study of NXP800 in ARID1a/ARID1b-deficient endometrial cancer xenografts, supporting the clinical development of NXP800 in this indication. Methods: Animal strain: CD1 Nude mice (nu/nu, Charles River). Human endometrial cancer cell lines: RL95-2 (ARID1a mutated, ATCC) and KLE (ARID1a wildtype, ARID1b mutated, ATCC), SNG-M (ARID1a mutated, Creative Bioarray). Xenograft tumors were generated by subcutaneous implantation on the right lower flank of the thigh at a cell density of 2 × 106 cells/mouse, at 0.1 ml Matrigel dilution volume/injection. Experiment groups: Vehicle, NXP800 (35 mg/kg); treatment: QD on days 0-4, 7-11, 14-18, 21-25, 28-30. Loss of ARID1A protein expression was confirmed by western blots. Results: In the SNG-M model, baseline tumor volume for the vehicle and NXP800 groups were 130.2, and 139.7 mm3, respectively, and on Day 32, average tumor volumes were 420.4, and 85.4 mm3, respectively, representing TGI of 81%. In the RL-95 model, baseline tumor volume for the vehicle and NXP800 groups were 124.5, and 129.9 mm3, respectively, and on Day 32, average tumor volumes were 773.8, and 190.3 mm3, respectively, representing TGI of 76%. In the KLE model, baseline tumor volume for both the vehicle and NXP800 groups were 88.1 mm3, respectively, and on Day 32, average tumor volumes were 216.4, and 18.9 mm3, for the vehicle and NXP800 groups, respectively, representing TGI of 91.3%. Conclusions: ARID1A and ARID1B genes encode the alternate, but obligatory, DNA-targeting subunit of the switch/sucrose non-fermentable (SWI/SNF) complex. ARID1A is the most frequently mutated SWI/SNF subunit across cancer types and is mutated in approximately 35% of endometrial carcinomas. NXP800 demonstrated robust antitumor activity in xenografts of endometrial carcinoma, a serious condition for which new treatment options are needed, including sustained tumor growth inhibition both in ARID1A and ARID1B mutated models, supporting the clinical development of NXP800 in endometrial cancer. Citation Format: Ramez N. Eskander, Bradley J. Monk, Brian M. Slomovitz, Enrique Poradosu, Allison Woods, Shay Shemesh, Paul Clarke, Robert Te Poele, Marissa Powers, Paul Workman, Shannon N. Westin. NXP800, a novel, small molecule GCN2 kinase activator, demonstrates potent single-agent activity in ARID1A and ARID1B-deficient endometrial cancer xenograft models [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr A016.

A drug delivery platform using engineered MUC1‐targeting exosomes enhances chemosensitivity and immunogenic cell death in pancreatic ductal adenocarcinoma

AbstractExosomes, a specific subset of extracellular vesicles, have diverse functions in various biological processes. In the field of cancer research, there has been a growing interest in the potential of exosomes to act as versatile vehicles for targeted tumor imaging and therapy. In this study, we constructed a targeted delivery platform using hypoimmunogenic exosomes by genetically modifying β2‐microglobulin knocking‐out HEK‐293F cells to express a fusion protein, referred to as αMUC1‐Exo, which comprises the exosomal membrane‐enriched platelet‐derived growth factor receptor, intracellular nanoluciferase, and extracellular anti‐MUC1 single‐chain variable fragment. The findings of this study indicate that αMUC1‐Exos exhibited notable drug delivery properties toward MUC1‐positive pancreatic cancer cells, resulting in a substantial inhibition of tumor growth. Moreover, these exosomes demonstrated a high level of biosafety and the absence of any adverse effects. The application of engineered exosomes as a vehicle for drug delivery holds promise for enhancing the immunogenicity of neoplastic cells following treatment, thereby inducing antitumor immune memory in mice with intact immune systems, and also improving the response to anti‐PD1 therapy. This approach utilizing engineered exosomes for Gemcitabine administration holds promise as a potential strategy for overcoming drug resistance in pancreatic carcinoma thereby improving the overall treatment efficacy.

Abstract A001: Discovery of imidazo [4,5-c]pyridin-2-ones as selective inhibitors of DNA-dependent protein kinase and effective radiosensitizers

Abstract Inhibition of the repair of radiation-induced DNA double strand breaks (DSB) offers the potential to sensitize tumors to radiation therapy. The dominant role of non-homologous end-joining in the repair of radiation-induced DSBs indicates that DNA-dependent protein kinase (DNA-PK) is an excellent target for the development of radiosensitizers. We report the discovery of a new chemical class of kinase inhibitor based on the imidazo[4,5-c]pyridin-2-one scaffold. The class was developed by scaffold-hopping from the pan phosphoinositide 3-kinsase (PI3K) and PI3K-like kinase (PIKK) inhibitor dactolisib. Iterative development culminated in the identification of SN39536 as a low nM DNA-PK inhibitor with excellent selectivity. Further modification led to the discovery of the more potent and more selective SN40905. Both SN39536 and SN40905 were effective inhibitors of DNA-PK kinase activity in a biochemical assay with substantial selectivity for DNA-PK across the PIKK and PI3K families. Both compounds selectively inhibited growth of HAP1 PRKDC wild-type cells when combined with radiation, but not the corresponding PRKDC-/- cells. SN39536 and SN40905 were effective radiosensitizers of colorectal carcinoma (HCT116), non-small cell lung cancer (H460, H1299, and A549), pancreatic (BxPC-3, PANC-1, and MiaPaCa-2) and head and neck squamous cell carcinoma (FaDu and UT-SCC-74B) cells determined using a clonogenic survival endpoint. Both SN39536 and SN40905 displayed high oral bioavailability. When administered PO at a range of non-toxic doses, both SN39536 and SN40905 provided significant additional tumor cell killing of HCT116, UT-SCC-74B, and BxPC-3 tumor xenografts in combination with a single (13 Gy) radiation treatment determined by ex vivo clonogenic survival assays. SN39536 also provided substantial tumor growth inhibition of HCT116 tumor xenografts in combination with RAD (10 Gy). SN39536 and SN40905 represent a new, potent, and selective class of DNA-PK inhibitors with significant potential as radiosensitizers for the treatment of human cancers. Citation Format: Michael P. Hay, Cho R. Hong, Lydia P. Liew, Benjamin D. Dickson, Way W. Wong, Sophia F. O'Brien-Gortner, Rebecca Airey, Jagdish Jaiswal, William R. Wilson, Stephen M. Jamieson. Discovery of imidazo [4,5-c]pyridin-2-ones as selective inhibitors of DNA-dependent protein kinase and effective radiosensitizers [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr A001.

Novel aromatic moieties-modified poly(glycidyl amine)s with potent siRNA delivery and cancer treatment effect.

The development of safe and effective delivery systems is critical for the clinical applications of siRNA-based therapeutics. Polymer-based vectors have garnered significant attention owing to their structural flexibility and functional tunability. Polyethyleneimine (PEI) has been extensively studied for nucleic acid delivery; nevertheless, its high cytotoxicity has posed challenges for clinical applications. In this study, we have reported poly(glycidyl amine) (PGAm), a linear PEI analogue, demonstrating remarkable siRNA delivery efficacy and improved biocompatibility. By introducing three aromatic moieties (tyrosine, p-hydroxybenzenepropanoic acid, and phenylalanine) at varying ratios to further modify PGAms, we successfully constructed a library comprising 36 PGAm-based carriers. In vitro evaluations revealed that PGAm-based carriers exhibited significantly enhanced biocompatibility and reduced non-specific protein absorption in comparison to PEI25k. Among them, 10 modified PGAms achieved a knockdown of target gene expressions exceeding 80%, and 26 modified PGAms maintained over 70% cell viability when utilized for the in vitro delivery of siRNA to HeLa cells. Explorations into the structure-activity relationship of PGAm-based polyplex nanoparticles (NPs) indicated that the siRNA delivery efficacy of NPs depended on factors such as the molecular weight of PGAm precursors, the type of modifying moieties, and the modification ratio. Furthermore, it was demonstrated that two top-performing NPs, namely 2T100/siLuc and 2A50/siLuc, exhibited potent silencing of target genes in tumors following i.v. injection into mice bearing HeLa-Luc xenografts. The in vivo efficacy of the selected NPs was further validated by a remarkable anti-cancer effect when employed for the delivery of siRNA targeting polo-like kinase 1 (siPLK1) to mice with PC-3 xenograft tumors. The intravenous administration of NPs resulted in a substantial inhibition of tumor growth without significant toxicity. These findings demonstrate the feasibility of employing PGAm in siRNA delivery and provide valuable insights for the development of efficient siRNA carriers based on PGAm.

Lactoferrin docking NIR-II cyanine dye as a potentiated phototheranostic for synchronous multimodal bioimaging and tumor photo-immunotherapy.

Rationale: A promising dye for phototheranostics, IR-1048 is a near-infrared region II (NIR-II) cyanine dye that exhibits exceptional optical characteristics in NIR-II spectrum. Unfortunately, the biological applications of IR-1048 are challenged by its hydrophobic nature, the formation of face-to-face stacked dimeric aggregates (H-aggregates) that result in pronounced spectral blue shifts, and issues related to fluorescence quenching. Method: We present a novel docking strategy involving bovine serum albumin (BSA) and lactoferrin (Lf) to construct BSA@IR-1048 and Lf@IR-1048 nanoprobes. The NIR-II optical characteristics of these nanoprobes have been thoroughly investigated through both theoretical and experimental approaches. In addition, we conducted in vitro and in vivo evaluations of their NIR-II photothermal and photodynamic properties, multimodal imaging capabilities, and effectiveness in photoimmunotherapy. Results: Following the protein docking process, both BSA@IR-1048 and Lf@IR-1048 probes exhibited a red-shifted absorbance peak and an "ON" state in NIR-II fluorescence. Theoretical analyses alongside experimental results indicate that Lf@IR-1048, which has a higher docking binding energy of -10.83 kcal/mol, significantly enhances optical characteristics in the NIR-II region. Notably, when utilizing a single NIR-II light source, Lf@IR-1048 was effective in producing single-linear state oxygen and converting photons into heat energy, achieving a photo-thermal conversion efficiency of 41.9%. The overexpression of transferrin receptors in tumor cells also improved tumor-targeting and enrichment capabilities of Lf@IR-1048, as demonstrated vitro and in vivo studies. Comparatively, Lf@IR-1048 facilitated multimodal imaging-guided NIR-II phototherapy, showing an impressive tumor development inhibition rate of 94.8%. Furthermore, in bilateral CT26 tumor-bearing mice, the Lf@IR-1048-based photo-immunotherapy exhibited significant antitumor activity, attributed to enhanced dendritic cell maturation and infiltration of cytotoxic T lymphocytes. Conclusion: Lf@IR-1048 displays a powerful combination of photothermal therapy, photodynamic therapy, and tumor-targeting potential for effective multimodal imaging-guided NIR-II phototherapy, leading to substantial inhibition of tumor growth.

Abstract B044: Results of a phase 1 dose escalation clinical trial of NXP800, a novel GCN2 activator, in patients with advanced or metastatic solid tumors

Abstract Background: NXP800 is an antineoplastic, oral, small molecule discovered in a phenotypic screen for inhibitors of the heat shock factor 1 stress response. In a panel of human carcinoma cell lines NXP800 induced the expression of genes associated with activation of the integrated stress response (ISR). Orthogonal experimental approaches revealed that activation of the kinase GCN2 was required for ISR activation by NXP800. In tumor samples from ARID1a-mutated ovarian carcinoma xenografts, treatment with NXP800 resulted in substantial tumor growth inhibition and tumor regressions. Induction of the ISR effector ATF4 was observed. Here we present data on the safety, pharmacokinetics and pharmacodynamics of NXP800 from the dose escalation phase 1 trial in patients with advanced or metastatic solid tumors. Methods: This is a first-in-human, open label, dose escalation and expansion Phase 1 study in patients with advanced solid tumors (Part A, all comers) and ovarian cancer (Part B).Dose escalation was guided by a Bayesian modified continual reassessment method that targeted a dose-limiting toxicity DLT probability (DLTp) closest to 30% but &amp;lt;33%.The primary objective of the dose escalation was to identify a dose and dosing schedule for Part B, in which the clinical activity of NXP800 is being evaluated in patients with platinum resistant,ARID1a-mutated ovarian carcinoma. Results: Eighteen patients were treated in Part A: at baseline, the median age was 65 years (range 42-77), 9 (50%) were female and 14/18 (78%) had an ECOG score of 1. Two schedules (once per day [QD] and twice per day [BID] and a dose range of 50 to 150 mg/day were evaluated. The most common (incidence &amp;gt;20%) non-laboratory, treatment emergent adverse events (TEAEs) were vomiting, nausea, diarrhea, fatigue, and decreased appetite, all reported as Grade 1-2 except for nausea and diarrhea that were reported as Grade 3 in one patient each. The most common laboratory TEAEs were thrombocytopenia and aspartate aminotransferase increase, all reported as Grade 1-2 except in two patients in whom thrombocytopenia was reported as Grade 3. Two Grade 4 TEAEs that were considered unrelated to study drug and no Grade 5 TEAEs were reported. The DLT for the QD schedule was 150 mg/day, with an estimated Dose Limiting Toxicity Probability (DLTp) of 34% (no doses in the BID schedule had estimated DLTp of &amp;lt;33%). The maximum tolerated dose was 100 mg/day (DLTp=26%). Model-based simulations demonstrated that NXP800 exposures obtained following 50, 75 and 100 mg QD were comparable to the drug exposure achieved in xenograft model of ARID1a-mutated ovarian carcinoma. ATF4 protein and ISR genes were induced in peripheral blood mononuclear cell samples obtained from patients treated with NXP800. Conclusion: The NXP800 doses and dosing schedules selected for Part B are 50 and 75 mg/day in a QD schedule. At these dose levels, NXP800 was tolerable, achieved relevant systemic exposure levels and induced ISR PD biomarkers. Part B is open for enrollment of patients with platinum resistant, ARID1a-mutated ovarian carcinoma. Citation Format: Udai Banerji, Simon Pacey, Karen Finkelstein, Simon Rodney, Ana Filipa Palma DosReis, Giovanni Codaccipisanelli, Mark Sloan, Florence I Raynaud, Ruth Ruddle, Karen Swales, Matthew Tall, Shay Shemesh, Diane Marsolini, Megan Sardone, Justin Hay, Robin Bliss, Enrique Poradosu, Paul Workman. Results of a phase 1 dose escalation clinical trial of NXP800, a novel GCN2 activator, in patients with advanced or metastatic solid tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B044.

Biolistic Delivery of Photosensitizer‐Loaded Porous Si Carriers for Localized Photodynamic Therapy

AbstractAmong numerous approaches for treating cancer, clinically approved photodynamic therapy (PDT) is considered a promising non‐invasive therapeutic strategy for solid tumors. While PDT has distinct advantages over conventional cancer treatments, systemic exposure to the photosensitizer and its stability are some of the limitations of clinical PDT. Herein, a therapeutic strategy for highly localized focal PDT is introduced based on direct biolistic delivery of photosensitizer‐loaded carriers to cancerous tumors. Degradable porous silicon microparticles (PSiMPs) are used as efficient carriers for the photosensitizer, meso‐tetrahydroxy‐phenylchlorin (mTHPC), and its conjugates with gold nanoparticles (AuNP‐mTHPC conjugates). The loaded PSiMP carriers are successfully bombarded using a pneumatic gene gun to breast cancer cells in vitro and into tumor xenografts in vivo, and subsequent uptake of the released photosensitizer payload is demonstrated. PDT irradiation is commenced after 24 h based on the release profile, resulting in complete cell death in vitro and substantial inhibition of tumor growth in vivo. Notably, using empty PSiMP carriers also leads to some tumor growth inhibition, ascribing to its intrinsic photosensitizing activity. Treatment with AuNP‐mTHPC‐loaded PSiMPs exhibits a superior therapeutic effect in comparison to bombarded mTHPC‐loaded carriers and administration of free mTHPC. This biolistic delivery scheme may be advantageous for precision photodynamic therapy.

TUG1-mediated R-loop resolution at microsatellite loci as a prerequisite for cancer cell proliferation

Oncogene-induced DNA replication stress (RS) and consequent pathogenic R-loop formation are known to impede S phase progression. Nonetheless, cancer cells continuously proliferate under such high-stressed conditions through incompletely understood mechanisms. Here, we report taurine upregulated gene 1 (TUG1) long noncoding RNA (lncRNA), which is highly expressed in many types of cancers, as an important regulator of intrinsic R-loop in cancer cells. Under RS conditions, TUG1 is rapidly upregulated via activation of the ATR-CHK1 signaling pathway, interacts with RPA and DHX9, and engages in resolving R-loops at certain loci, particularly at the CA repeat microsatellite loci. Depletion of TUG1 leads to overabundant R-loops and enhanced RS, leading to substantial inhibition of tumor growth. Our data reveal a role of TUG1 as molecule important for resolving R-loop accumulation in cancer cells and suggest targeting TUG1 as a potent therapeutic approach for cancer treatment.

A bispecific γδ T-cell engager targeting EGFR activates a potent Vγ9Vδ2 T cell-mediated immune response against EGFR-expressing tumors.

Vγ9Vδ2 T cells are effector cells with proven antitumor efficacy against a broad range of cancers. This study aimed to assess the antitumor activity and safety of a bispecific antibody directing Vγ9Vδ2 T cells to EGFR-expressing tumors. An EGFR-Vδ2 bispecific T-cell engager (bsTCE) was generated and its capacity to activate Vγ9Vδ2 T cells and trigger antitumor activity were tested in multiple in vitro, in vivo, and ex vivo models. Studies to explore safety were conducted using cross-reactive surrogate engagers in non-human primates (NHP). We found that Vγ9Vδ2 T cells from peripheral blood and tumor specimens of patients with EGFR+ cancers had a distinct immune checkpoint expression profile characterized by low levels of PD-1, LAG-3, and TIM-3. Vγ9Vδ2 T cells could be activated by EGFR-Vδ2 bsTCEs to mediate lysis of various EGFR+ patient-derived tumor samples and substantial tumor growth inhibition and improved survival were observed in in vivo xenograft mouse models using PBMCs as effector cells. EGFR-Vδ2 bsTCEs exerted preferential activity towards EGFR+ tumor cells and induced downstream activation of CD4+ and CD8+ T cells and NK cells without concomitant activation of suppressive regulatory T cells observed with EGFR-CD3 bsTCEs. Administration of fully cross-reactive and half-life extended surrogate engagers to NHPs did not trigger signals in the safety parameters that were assessed. Considering the effector and immune-activating properties of Vγ9Vδ2 T cells, the preclinical efficacy data and acceptable safety profile reported here provide a solid basis for testing EGFR-Vδ2 bsTCEs in patients with EGFR+ malignancies.

Abstract 3095: Development of a novel ADAR1 inhibitor as a potent immunomodulator for the treatment of solid tumors

Abstract Background: Adenosine deaminase, RNA specific (ADAR1), catalyzes the hydrolytic deamination of adenosine (A) to inosine (I) in double-stranded (ds) RNAs. There are 2 isoforms of ADAR1 (p110 in the nucleus; p150 in cytoplasm) and both modify self dsRNA in coding and non-coding regions​. The ADAR1 p150 isoform is expressed from an interferon (IFN)-response promoter and has a Z-DNA/Z-RNA binding domain at the N-terminus. ADAR1 p150 edits 3′-untranslated region dsRNAs comprising of inverted Alu repeats and thereby suppresses MDA5-MAVS-IFN signaling. ADAR1 is commonly overexpressed in multiple myeloma, breast, lung, liver, skin and esophageal cancer where it promotes cancer progression. Inhibition of ADAR1 has promising anti-tumor efficacy as monotherapy and in combination with checkpoint inhibitors, radiotherapy and chemotherapeutic modalities. Herein, we outline the discovery of a potential first-in-class ADAR1 inhibitor for cancer immunotherapy. Methods: AVA-ADR-001 was identified through a high throughput p110 knockout cell-based assay. The ability of AVA-ADR-001 to induce interferons was confirmed in various cell lines like A549 p110 KO, HCT116 and B16F10. Finally, the anti-tumor efficacy of AVA-ADR-001 was evaluated in B16F10 syngeneic melanoma mice model as monotherapy and in combination with anti-PD-1. Results: We have identified a first-in-class small molecule inhibitor of ADAR1, which shows significant IFN response in vitro in an MDA5 dependent manner. In vitro binding studies have confirmed direct binding of AVA-ADR-001 with the Zα domain of ADAR1 thus confirming its selectivity to the p150 isoform. AVA-ADR-001 demonstrates micromolar EC50 and anti-tumor efficacy against B16F10 melanoma syngeneic mouse model. 100 µg of AVA-ADR-001 treatment resulted in 45% tumor growth inhibition (TGI), 1.5x superior to Anti-PD1 treatment. Combining AVA-ADR-001 with Anti-PD1 demonstrated a synergistic effect 2x superior to Anti-PD1 alone. Additionally, several interferon stimulated genes like IFIH1, IFN-β and CXCL-10 were significantly upregulated in the tumor samples of the AVA-ADR-001 monotherapy and combination groups. Conclusions: To our knowledge no selective small molecule inhibitors of ADAR1 have been reported so far and AVA-ADR-001 is the first disclosure of such an inhibitor. AVA-ADR-001 is a potent and selective first-in-class ADAR1 inhibitor which has shown significant IFN induction in various cancer cell lines and in vivo in the tumor microenvironment resulting in substantial tumor growth inhibition as monotherapy and synergistically in combination with Anti-PD1. Considering the immune-suppressive and pro-metastatic role of ADAR1, AVA-ADR-001 serves as a promising starting point for novel ADAR1 inhibitors as therapeutic modalities in cancer immunotherapy. Keywords: Cancer immunotherapy, small molecule inhibitors, ADAR1, innate immunity Citation Format: Aditya Kulkarni, Avijit Goswami, Sandeep Goyal, Kawaljit Singh, Princy Khurana, Ishani Ghoshal. Development of a novel ADAR1 inhibitor as a potent immunomodulator for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3095.