Cancer Therapy Research Articles

Experimental and computational studies on possibility of using glucose diazacrown cryptand as a carrier for anticancer drugs busulfan and lomustine

AbstractDrug carriers play a very important role in pharmacy, especially in cancer therapy. Most drugs used in the treatment of cancer are characterized by poor solubility in water and lack of selectivity in their toxic effects on normal and cancer cells. Administration of the drug in the form of a complex with an appropriately selected carrier can significantly improve its therapeutic effect and reduce side effects. In this study, the possibility of using the cryptand L1, containing two diazacrown ethers and two saccharide groups, as a potential drug carrier is investigated. In order to determine whether it can form complexes with drugs, the cryptand L1 and its complexes with two anticancer drugs, busulfan (BSF) and lomustine (CCNU), were synthesized. Their selected structural and energetic properties were investigated using both experimental and computational methods. Additionally, water solubility and cytotoxicity tests were performed for all compounds. The measured 1H NMR spectra confirm that L1 forms complexes L1:BSF and L1:CCNU, the solubility of which in water appears to be much higher than that of the pure drugs. The results of DFT calculations made in water described with the implicit solvent model confirm high stability of L1:BSF and L1:CCNU and indicate that L1 forms with the drugs mainly non-inclusion complexes. However, additional tests with 20 H2O molecules explicitly included in the model suggest that both inclusion and non-inclusion forms can occur in a real solution. Cytotoxicity studies show that the macrocycle L1 is non-toxic towards both normal and cancer cells, and its complexes with drugs show greater selectivity towards cancer cells. Interestingly, while the cytotoxicity of the L1:BSF complex is stronger than that of pure BSF, the relationship is opposite in the case of L1:CCNU and CCNU. Therefore, L1 can be considered as a potential drug carrier, especially for those drugs that have weak activity on cancer cells.

MDT perspective: innovative applications of stereotactic body radiation therapy in metastatic castration-resistant prostate cancer

MDT perspective: innovative applications of stereotactic body radiation therapy in metastatic castration-resistant prostate cancer

Correlation Between Grade of Clinical Response to Neoadjuvant Therapy for Rectal Cancer and Oncologic Outcomes in the Era of Watch-and-Wait

Background: The watch-and-wait strategy provides an opportunity to pursue non-operative management in rectal cancer patients with clinical complete response after neoadjuvant therapy. The management of those with near complete response remains controversial. Objective: We assessed the oncologic outcomes of patients managed by watch-and-wait versus total mesorectal excision according to clinical response to neoadjuvant therapy. Design: Retrospective cohort study. Settings: Comprehensive cancer center in New York. Patients: Patients with rectal adenocarcinoma diagnosed between January 2006 to December 2020. Interventions: A watch-and-wait strategy of active surveillance was offered to patients if they achieved clinical complete response. Salvage surgery was utilized for watch-and-wait patients with local regrowth. Patients with an incomplete response underwent total mesorectal excision Main Outcome Measures: Local regrowth rate, organ preservation rate, disease-free survival and overall survival. Results: Patients with rectal adenocarcinoma (n = 1230) were divided into 3 response cohorts—incomplete (n = 646), near-complete (n = 189) and complete (n = 395). Eighty-one (43%) patients in the near-complete group and 351 (89%) patients in the complete group entered watch-and-wait. Three-year local regrowth rates were 40% and 24% in the near-complete and complete response cohorts, respectively. The 5-year organ preservation rate was 53% in near-complete responders, and 73% in complete responders. Five-year disease-free survival increased with greater clinical response to neoadjuvant therapy with intermediate outcomes noted for patients with a near-complete (73%) compared to complete (82%) or incomplete response (68%). Overall survival at 5 years was similar between the three cohorts (complete 90%, near-complete 86%, and incomplete 85%). Limitations: Retrospective nature. Conclusion: Greater clinical response to neoadjuvant therapy is associated with improved oncologic outcomes. Near-complete responders may avoid surgery and still achieve high organ preservation rates yet experience greater local regrowth rates than clinical complete response patients. Ongoing prospective trials integrating watch-and-wait after complete response as determined by uniform criteria will bolster the work to help treating physicians better select patients who qualify for active surveillance. See Video Abstract.

ASO Author Reflections: Enhancing Return to Intended Oncologic Therapy in Gastric Cancer—The Role of Minimally Invasive Gastrectomy

ASO Author Reflections: Enhancing Return to Intended Oncologic Therapy in Gastric Cancer—The Role of Minimally Invasive Gastrectomy

Abstract C033: Identifying and targeting prostate cancer therapy resistance mechanisms driven by the tumor microenvironment

Abstract Background: Prostate cancer is a prevalent malignancy in men, with treatment resistance posing a significant challenge to successful cure. Acquired Resistance to Therapy (ART) arises from two main components: (1) Tumor Microenvironment (TME) and (2) mutations or epigenetic changes at gene level within the tumor cells themselves. While most cancer therapies target the intrinsic biology of cancer cells, growing evidence indicates that these treatments can also harm the stromal cells within TME, potentially driving ART. The biology of ART may vary based on the types of treatments, cell types, and organ locations. Thus, this study aims to dissect ART components driven by TME-mediated cellular processes in a comprehensive manner. Hypothesis: We propose that cancer therapies induce stress responses in non-cancerous cells within the TME. These stress responses involve the secretion of cytokines, mediators, and growth factors, which we term Stress Response Secretory Programs (SRSPs). We further hypothesize that targeting SRSPs could overcome ART that helps to improve treatment specificity and efficacy. Materials and Methods: We employed comprehensive single-cell profiling of common metastatic sites included liver, prostate, lung, bone, lymph node and spleen in preclinical models to identify secreted proteins and dysregulated pathways caused by genotoxic therapies. In vitro, we evaluated treatment resistance in murine prostate epithelial cell lines (Myc-CAP) by exposing them to conditioned media (CM) from irradiated murine fibroblasts (F4M2), using cell growth assays. Results: Single-cell RNA sequencing of organ samples revealed significant expressions of SRSPs and increased inflammatory responses in liver and prostate fibroblasts as well as other stromal cells treated with carboplatin. In vitro, CM from irradiated F4M2 cells enhanced cell proliferation and survival of Myc-CAP cells in response to docetaxel treatment. Conclusion: Our findings highlight the crucial role of SRSPs in mediating ART through interactions within the TME, which alter tumor cell phenotypes. Targeting these SRSPs holds potential for overcoming treatment resistance and improving therapeutic outcomes, underscoring the need to consider TME complexity in cancer treatment strategies. Citation Format: Tony Lok Heng Chu, Armand Bankhead, Ilsa Coleman, Sander Frank, Peter S. Nelson, Tarana Arman. Identifying and targeting prostate cancer therapy resistance mechanisms driven by the tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C033.

Abstract IA025: Targeting the gut microbiome for cancer immunotherapy

Abstract Growing evidence suggests that the gut microbiota modulates the efficacy and toxicity of cancer therapy, most notably immunotherapy and its immune-related adverse effects. The impaired response to immunotherapy in patients treated with antibiotics supports this role of the microbiota. Until recently, results pertaining to the identification of the microbial species responsible for these effects were incongruent, and relatively few studies analyzed the underlying mechanisms. Gut microbial communities (microbiotypes) with non-uniform geographic distribution were associated with favorable and unfavorable outcomes, contributing to discrepancies between cohorts Now, a better understanding of the taxonomy of the species involved and of their mechanisms of action has been achieved. Defined bacterial species have been shown to promote a response to immune checkpoint inhibitors through the production of different products or metabolites, although a suppressive effect of Gram(-) bacteria may be dominant in some unresponsive patients. Machine learning approaches trained on patients’ microbiota composition can predict the ability of patients to respond to immunotherapy with some accuracy. Thus, the interest in modulating the microbiota composition to improve patients’ responsiveness to therapy has been mounting. Our data of a fecal microbiota transfer clinical trial in anti-PD1 refractory melanoma patients has provided clinical proof of concept of the possibility to target the gut microbiota composition in cancer therapy. Also, both in clinical studies and in experimental animals, diets rich in fibers improve the response to immunotherapy by modifying the gut microbiome suggesting the possibility of dietary approaches to target the microbiota composition in cancer therapy. However, while many early clinical studies have analyzed the association of the microbiota composition with the response to anti-PD-1 in cancer patients, emerging evidence suggests that the association may be context dependent and different types of mono or combination immunotherapies may be differentially regulated by the microbiota, Thus, a more personalized approach depending original gut microbiota composition of the patients and the type of immunotherapy protocol selected may be necessary for optimal clinical results. Citation Format: Giorgio Trinchieri. Targeting the gut microbiome for cancer immunotherapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr IA025.

Abstract C047: AGX101: Preclinical evaluation of a TM4SF1-directed tubulin inhibitor conjugate with ongoing first-in-human trial

Abstract Introduction: TM4SF1 (Transmembrane-4 L-Six-Family-Member-1) is an endothelial marker with critical roles in angiogenesis, as well as a tumor cell antigen that contributes significantly to invasion and metastasis. TM4SF1 is upregulated 20-fold in angiogenic tumor vascular endothelium compared to normal vasculature endothelium and exhibits a unique nuclear internalization pathway. AGX101 is a novel tubulin inhibitor conjugate specifically directed against TM4SF1, delivering a potent maytansinoid payload directly to the nucleus of cells within the tumor microenvironment. Delivery to both the vascular and tumor cell compartments of the tumor results in three mechanisms of action (MoAs): (1) activation of tumor immune surveillance, (2) tumor blood supply deprivation, and (3) direct tumor cell killing. Methods: TM4SF1 expression was assessed across solid tumor samples using immunohistochemistry. Safety and pharmacokinetics of AGX101 were evaluated in non-human primates, with escalating doses to determine the highest non-severely toxic dose (HNSTD). Efficacy studies were also conducted in mouse models, enabling assessment of the minimum effective dose (MED) needed to engage each of the three MoAs. The combination of HNSTD and MED enables calculation of a therapeutic index (TI). Preclinical efficacy studies used either AGX101 (in human tumor xenograft models, to study the tumor cell killing MoA) or AGXB01, a rodent surrogate of AGX101, to study vascular and immune MoAs and all three MoAs in syngeneic mouse cancer models. The potential for synergy with immune checkpoint inhibitors (ICIs) was also investigated. A first-in-human study of AGX101 in patients with advanced solid tumors with the primary objective of safety and dose-limiting toxicities (DLTs) has initiated. Results: TMFS41 is broadly expressed across solid tumors with increasing scoring intensity in higher grade tumors. In non-human primates, AGX101 exhibited a favorable safety profile, being tolerated at relatively high doses and with dose dependent, monitorable, and reversible effects. In preclinical efficacy studies, AGXB01 and AGX101 as monotherapies demonstrated robust efficacy through each of the three MoAs in multiple syngeneic, xenograft, and orthotopic tumor models in mice and rats as well as non-tumor models of angiogenesis. Measured by exposure, TI was large. Additionally, AGXB01 was shown to potentiate the effects of ICIs in syngeneic mouse models (CT26, Renca, and B16-F10), suggesting a potential synergistic approach in cancer therapy. The first dose level of AGX101 monotherapy in humans has cleared without DLTs. Conclusion: AGX101, targeting the TM4SF1 antigen, represents a promising new approach in cancer therapy. The preclinical data suggest that AGX101 could provide a significant therapeutic benefit by novel and differentiated mechanisms of action, namely selectively targeting the tumor vasculature and potentiating immune-based therapies. Further clinical development of AGX101 is ongoing. Citation Format: Ildefonso Ismael Rodriguez Rivera, Meredith S. Pelster, Shou-Ching Jaminet, Paul Jaminet, Glen J. Weiss. AGX101: Preclinical evaluation of a TM4SF1-directed tubulin inhibitor conjugate with ongoing first-in-human trial [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C047.

Abstract C029: PM2.5-induced drug resistance in lung cancer

Abstract Long-term exposure to PM2.5 air pollution is a significant contributor to lung cancer incidence. Our previous studies have shown that such exposure promotes lung cancer progression by activating the EGFR (epidermal growth factor receptor) and AhR (aryl hydrocarbon Receptor) pathways. We observed that in lung cancer cells with EGFR mutations, prolonged PM2.5 exposure induces EGFR activation, resulting in accelerated tumor cell growth both in vitro and in vivo. This suggests that PM2.5 may play a role in the resistance to EGFR-TKI (tyrosine kinase inhibitor) therapies, raising concerns about treatment efficacy. To explore this, we exposed the EGFR-mutant lung cancer cell line to PM2.5 for 90 days. Our results revealed that long-term exposure not only reduced the therapeutic effect of EGFR-TKIs but also increased the expression of cMyc, a gene linked to poor prognosis and drug resistance. We further confirmed that PM2.5-induced EGFR-TKI resistance is driven by the AhR-cMyc pathway. AhR, activated by environmental toxins in PM2.5, increases cMyc expression, leading to drug resistance. When we administered cMyc inhibitors, the PM2.5-exposed cells regained sensitivity to EGFR-TKI therapy. These findings indicate that targeting the AhR-cMyc pathway could be a promising approach to overcome PM2.5-induced resistance in lung cancer treatment. Further research is needed to explore the broader implications of environmental pollution on cancer therapy and to develop strategies to counteract the effects of pollutants like PM2.5. Citation Format: Chi-Yuan Chen, Chieh-Wen Chan, Tong-Hong Wang. PM2.5-induced drug resistance in lung cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C029.

Synthetic Biology-Enabled Engineering of Probiotics for Precision and Targeted Therapeutic Delivery Applications

Probiotics, defined as live microorganisms that offer health benefits when consumed in adequate amounts, have traditionally been used to maintain gastrointestinal (GI) health. They are effective in managing conditions such as inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and antibiotic-associated diarrhea. Recent research, however, has expanded their potential applications beyond the GI tract to include immune modulation, metabolic regulation, and mental health support. Despite these advances, conventional probiotics face limitations such as instability in harsh environments, lack of precise targeting, and ineffective control over drug release. This review explores the application of synthetic biology in addressing these limitations, emphasizing how tools such as CRISPR-Cas systems, synthetic gene circuits, and plasmid-based mechanisms enhance the stability, functionality, and specificity of engineered probiotics for therapeutic delivery. Applications of synthetic biology-enabled probiotics are examined across a range of health contexts, including GI health, cancer therapy, metabolic disorders, immune modulation, and mental well-being. Synthetic biology tools provide precise genetic modifications that improve the stability, viability, and functionality of engineered probiotics, enabling more targeted therapeutic delivery. Additionally, technologies such as encapsulation support probiotic survival, while gene circuits allow programmable, stimulus-responsive therapeutic release. As synthetic biology continues to advance, the development of programmable probiotics holds promise for personalized, targeted medicine, positioning probiotics as living therapeutics and patient-friendly alternatives to conventional therapeutic delivery systems.

Abstract B005: Exploring breast cancer heterogeneity in the context of metastatic tumour microenvironments and therapy resistance

Abstract Breast tumors comprise several sub-populations of cells, so-called “clones”, with specific cellular and molecular characteristics. Some cancer clones can be more ‘aggressive’ than others in particular tumor microenvironments (TMEs), contributing to metastatic progression and drug resistance. Understanding the specific genes/pathways deregulated in these aggressive cancer cells is essential for developing new tailored treatment strategies. To accomplish this, we optimized the use of a lentiviral-based barcoding technique (Berthelet, J., et.al., Sci Adv 2021, Serrano, A., et.al., Nat Rev Cancer 2022) where cancer cells from cell lines and patient-derived xenografts are tagged with optical barcodes and transplanted into the mammary fat pads of immunodeficient mice. Upon resection of tumors and collection of metastatic organs at the experimental endpoint, we analyzed clonal fate and fitness using flow cytometry and imaging. The subsequent molecular characterization of individual clones was determined by bulk and single-cell RNA sequencing. We also leverage the use of these barcoded models to investigate the mechanisms of innate and acquired resistance to Sacituzumab Govitecan (SG), a drug recently approved for the treatment of patients with advanced breast cancer. Our studies revealed unique gene signatures and pathways associated with preferential organ tropism (in the lungs, liver and brain TMEs) and SG resistance. This comprehensive analysis, currently validated using autopsy samples and patient databases, will support the design of new predictive markers and targeted therapies for metastatic breast cancer. Citation Format: Sreeja Reddy Gadipally, Jean Berthelet, Samuel C. Lee, Dharmesh D. Bhuva, Michael Roach, Farrah El-Saafin, Caroline Bell, Yunjian Wu, David Baloyan, Christphe Ginestier, Charafe Jauffret Emmanuelle, Melissa Davis, Robin L. Anderson, Luciano Martelotto, Belinda Yeo, Delphine Merino. Exploring breast cancer heterogeneity in the context of metastatic tumour microenvironments and therapy resistance [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B005.

Chaga Mushroom Triterpenoids Inhibit Dihydrofolate Reductase and Act Synergistically with Conventional Therapies in Breast Cancer

Inonotus obliquus (Chaga) is a medicinal mushroom with several pharmacological properties that is used as a tea in traditional Chinese medicine. In this study, Chaga water extract was digested in vitro to mimic the natural processing and absorption of its biocomponents when it is consumed as functional beverage, and its anticancer activities were evaluated in breast cancer (BC) cell lines, representing HER2-positive and triple-negative subtypes. After chemical characterization by liquid chromatography/mass spectrometry (HR-QTOF) analysis, the effect of Chaga biocomponents on cell viability and cell cycle progression was assessed by MTT assay, FACS analysis, and Western blot. Dihydrofolate reductase (DHFR) activity was measured by an enzymatic assay. Four highly bioactive triterpenoids (inotodiol, trametenolic acid, 3-hydroxy-lanosta-8,24-dien-21-al, and betulin) were identified as the main components, able to decrease BC cell viability and block the cell cycle in G0/G1 by inducing the downregulation of cyclin D1, CDK4, cyclin E, and phosphorylated retinoblastoma protein. DHFR was identified as their crucial target. Moreover, bioactive Chaga components exerted a synergistic action with cisplatin and with trastuzumab in SK-BR-3 cells by inhibiting both HER2 and HER1 activation and displayed an immunomodulatory effect. Thus, Inonotus obliquus represents a source of triterpenoids that are effective against aggressive BC subtypes and display properties of targeted drugs.

Abstract C020: Discovery & characterization of small molecules to enhance Natural Killer cell cytotoxicity against solid tumors

Abstract While adoptive cellular therapies (ACT) such as CAR-T and NK therapy have shown clinical efficacy against hematologic malignancies, their use against solid tumors (such as ovarian or pancreatic cancer) has had limited success to date. In particular, CAR-T therapy for solid cancers has led to severe toxicities, including on-target, off-tumor killing of healthy cells and graft vs. host disease (GVHD) with allogeneic transplant. NK cell therapies, in contrast, have fewer associated toxicities due to specific and innate recognition/killing of cancer cells. This greater safety profile makes NK therapies an attractive treatment option for solid cancers. NK therapies are currently limited by insufficient in vivo tumor clearance, caused largely by their lower cytotoxicity and in vivo expansion compared to CAR-T cells. To address this, we have screened 300,000 small molecule compounds for their ability to enhance NK cytotoxicity against ovarian cancer (OVCAR) cells. Our primary screen identified 11 lead compounds which increase NK killing activity against OVCAR cells >= 10% over baseline (vehicle-treated control). Secondary in vitro assays have confirmed that at least 3 out of 11 lead compounds enhance NK cytotoxicity by at least 10% over baseline. As such, we hypothesize that our lead compounds will increase in vivo NK cytotoxicity and tumor clearance, through mechanisms which might include I) upregulation of NK activating receptors, II) downregulation of NK inhibitory receptors, and/or III) modulation of NK metabolism in the immunosuppressive tumor microenvironment. Immediate future studies include in vivo testing of our lead compounds’ ability to enhance NK cytotoxicity, using immunodeficient mouse models of subcutaneous OVCAR tumors. Moreover, we will utilize 2D and 3D in vitro culture techniques alongside flow cytometry and RNA sequencing to identify how lead compounds impact markers of NK activation and metabolism. This will include expression of activating/inhibitory receptors, exhaustion markers, and key metabolic factors. Finally, we will assess the effect of lead compounds on NK function within an immunosuppressive tumor environment. Our findings will contribute to effective future NK cell therapies for solid tumors. Citation Format: Indrani Das, Olubukola Abiona, Riufu Liu, Grace K. Lee, David N. Wald. Discovery & characterization of small molecules to enhance Natural Killer cell cytotoxicity against solid tumors [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C020.

Abstract B018: Multifaceted pro-metastatic role of IL-17 signaling in modulating the tumor microenvironment of colorectal cancer

Abstract Colorectal cancer (CRC) ranks second in mortality and advanced CRCs are resistant to current immunotherapies and prone to metastasis, which necessitates research into enhancing innate and adaptive anti-cancer immune responses. Chronic inflammation mediated by cytokines like IL6 and notably, IL17 activates the oncogenic pathways in cancer cells, promoting sporadic and inflammatory CRC. What is unknown, is the ability of cytokines to control tumor microenvironment (TME) via cell type specific mechanisms to increase cancer progression, metastasis and/or therapy resistance. Increased levels of IL17A in CRC portends poor prognosis indicating its potential involvement into metastasis. However, the role of IL17 signaling in TME in the process of CRC progression and metastasis remains enigmatic. We utilized different models of CRC progression and metastasis, as well as variety of genetic mice models and therapeutic interventions. First, using a model of colitis-associated cancer we found that “late” IL17A neutralization decreases tumor burden, possibly acting through regulation of ferroptosis, NK cells mediated cytotoxicity, as well as myeloid cells and chemokine network essential for the control of immunosuppressive TME. Next, models of CRC metastasis, including those based on MC38 cells and APTAK cancerous organoids, showed that IL17A neutralization reduces metastasis growth. Also, FACS analysis revealed that IL17A promotes the recruitment of tumor- associated macrophages and other key myeloid subsets into the metastatic liver environment. Further research, using mice with conditional knockout of IL17RC receptor in myeloid cells (Il17rc f/f -LysMCre) or hepatocytes (Il17rc f/f -AlbCre) also showed significance of IL17 signaling activation in CRC metastasis through two distinct mechanisms. Employing different techniques, from FACS, immunohistochemistry, to RNAseq and scRNAseq data analysis, we observed that local hepatic activation of IL17RC signaling recruits neutrophils and reduces infiltration of cytotoxic CD8+T and NK cells to the metastatic niche supporting tumor growth, while myeloid IL17RC signaling reshapes TME, including macrophages and neutrophils, enhancing CRC metastasis. Our research indicates that IL17 signaling plays a multifaceted pathogenic role in CRC progression by operating in at least several cell types, providing new insights into the basic biology of CRC metastasis and potentially illuminating the design and improvement of CRC treatment strategies. Citation Format: Katarzyna Chojnacka, Katrina Mae Reyes, Hana Tomizawa, Sergei Grivennikov. Multifaceted pro-metastatic role of IL-17 signaling in modulating the tumor microenvironment of colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B018.

Abstract C001: Cytomegalovirus infection modulates distinct immune cell dynamics across tumor-immune microenvironments and systemic macroenvironment during metastasis

Abstract Cytomegalovirus (CMV) is ubiquitously present worldwide and has been implicated in the modulation of cancer development and spread. Notably, CMV proteins have been detected in approximately 90% of lymph node and brain metastases in breast cancer, suggesting its potential influencing tumor invasiveness and metastases. This study investigates the effects of CMV infection on the tumor microenvironment and macroenvironment during metastatic progression in triple-negative breast cancer (TNBC). We employed a syngeneic TNBC mouse model designed to develop spontaneous metastases following primary tumor resection. Using multi-omics sequencing and comprehensive analysis tools, we characterized the tumor-immune landscape across multiple organs relevant to CMV infection and tumor metastasis, including blood, bone marrow, spleen, lungs, brain, and lymph nodes. Our results demonstrate that CMV infection systematically activated the immune response, suppressing primary tumor growth and subsequent metastasis. At the primary tumor site, prior to metastasis, CMV-infected mice exhibited significantly lower proportions of macrophages and plasma cells compared to uninfected counterparts, while CD8+ T cells were significantly enriched. In contrast, the proportions of neutrophils and dendritic cells did not significantly differ between the groups. Distinct patterns of immune cell dynamics were observed at metastatic sites. In the spleen of CMV-infected mice, a notable reduction in macrophages and elevated neutrophil levels were detected. Lung tissues displayed a marked increase in macrophages, CD8+ T cells, and dendritic cells in CMV-infected mice. Interestingly, in the blood, we noted a decreased proportion of natural killer cells in CMV-infected mice. However, no significant difference in plasma cell percentages was observed between CMV-infected and uninfected mice in metastatic lung tissues. The cell-cell interaction analysis further showed a complex crosstalk network between immune cells as well as tumor and immune cells. These findings highlight the profound impact of CMV infection on remodeling the immune landscape at both primary tumors and metastatic sites. The distinct immune cell dynamics orchestrated by CMV infection underscore the virus's role in modifying tumor-immune microenvironments and macroenvironments. Our study offers novel perspectives for developing targeted cancer therapies that consider the complex interactions between viral infections and the tumor immune axis. Further research is warranted to elucidate the mechanisms underlying CMV-mediated immune modulation at molecular level and its potential therapeutic implications in TNBC and other cancer types. Citation Format: Wenjuan Dong, Jianting Sheng, Shan Xu, Matthew Vasquez, Hong Zhao, Stephen T.C Wong. Cytomegalovirus infection modulates distinct immune cell dynamics across tumor-immune microenvironments and systemic macroenvironment during metastasis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C001.

Abstract C036: Pharmacological modulation of glutamine metabolism alters macrophage activity and tumor immune responses

Abstract As a critical component of innate and adaptive immunity, macrophages play an important role in shaping the tumor microenvironment (TME), which affects tumor initiation, progression, and response to treatment. Tumor-associated macrophages can display anti-tumor or pro-tumor activity, a cell fate attributed to macrophage polarization that depends on metabolomic regulation. Targeting macrophage metabolism could be a promising approach for cancer treatment by converting a pro-tumor TME into an anti-tumor TME. To examine in vivo mechanisms behind glutamine metabolism on macrophages, we treated immunocompetent murine ovarian cancer models with a clinical-grade glutamine prodrug, JHU083, and performed single-cell RNA sequencing (scRNAseq). In addition to the significant anti-tumor efficacy of JHU083, we found that JHU083 specifically suppressed the M2-like tumor macrophages while sparing M1-like macrophages. To better understand the molecular mechanism of how JHU083 causes macrophage polarization shift, we cultured an M1-like macrophage cell line with DON (6-Diazo-5-oxo-L-norleucine), the active component of JHU083, and performed bulk RNA sequencing. Using bulk RNAseq and scRNAseq transcriptome analyses on M1-like macrophages, glutamine inhibitor treatment significantly enhanced MHC class II genes, including CD74, H2-Aa, H2-Eb1, H2-Ea, H2-Ab1, and TNF family genes including Tnfsf12, and Tnfrsf14 which may promote T cell trafficking and cytotoxicity through reversing immunosuppressive tumor microenvironment. Moreover, DON-treated bone marrow-derived M1 macrophages promoted CD4+ T cell expansion. On the other hand, DON treatment significantly suppressed bone marrow-derived M2 macrophages. In conclusion, our findings suggest that glutamine metabolism reprogramming can promote anti-tumor functions in tumor macrophages. Therefore, targeting glutamine metabolism to regulate macrophage function and polarization can be a promising direction for future cancer therapy. Citation Format: Jiawei Fan, Sumeng Qi, Ie-Ming Shih, Tian-Li Wang. Pharmacological modulation of glutamine metabolism alters macrophage activity and tumor immune responses [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C036.

Abstract A018: Endothelial pyrimidine synthesis deficiency promotes tumor growth

Abstract The tumor microenvironment plays a crucial role in cancer progression and treatment response. Systemically administered metabolic cancer therapies target not only malignant but also stromal cells, including immune cells - the only stromal population previously addressed in this context. However, how such treatments impact other non-malignant cell types in tumors remains poorly understood. Here we show that inhibition of de novo pyrimidine synthesis in endothelial cells accelerates tumor growth and alters tumor immune repertoire. We found that whole-body de novo pyrimidine synthesis deficiency in mice, caused by the inducible whole-body ablation of DHODH, accelerates the growth rate of orthotopic lung tumors. Single-cell transcriptomic analysis of tumor-bearing lungs revealed that DHODH deficiency in the stroma impacts multiple cell populations, including immune and, surprisingly, endothelial cells. To explore the endothelial-specific effects, we generated a mouse model with inducible DHODH deficiency restricted to endothelial cells. The endothelium-specific model recapitulates the accelerated lung tumor growth observed in the whole-body DHODH deficiency model. Single-cell transcriptomics analysis of tumor-bearing lungs in the endothelium-specific model pointed to changes in the immune repertoire, particularly an enrichment of monocytes. We confirmed these results on the protein level using spectral flow cytometry, and we are currently in the process of uncovering the mechanism by which endothelial deficiency of pyrimidine synthesis affects the immune landscape of tumors. Inhibitors of pyrimidine de novo synthesis have been tested in clinical trials but failed due to their low efficiency. Our findings indicate that systemic treatment targeting pyrimidine synthesis may be hampered by its pro-tumorigenic effects in the endothelium, highlighting the unexpected role of endothelial metabolism in this context. Citation Format: Petra Hyrossova, Isidora Milisav, Silvia Novais, Mirko Milosevic, Jakub Rohlena, Katerina Rohlenova. Endothelial pyrimidine synthesis deficiency promotes tumor growth [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A018.

PinX1 plays multifaceted roles in human cancers: a review and perspectives.

Pin2/TRF1 interacting protein X1 (PinX1), a telomerase inhibitor, is located at human chromosome 8p23. This region is important for telomere length maintenance and chromosome stability, both of which are essential for regulating human ageing and associated diseases. We investigated the research progress of PinX1 in human cancers. In cancers, the expression levels of PinX1 mRNA and protein vary according to cancer cell types, and PinX1 plays a critical role in the regulation of cancer development and progression. Additionally, a review of the literature indicates that PinX1 is involved in mitosis and affects the sensitivity of cancer cells to radiation-induced DNA damage. Therefore, PinX1 has therapeutic potential for cancer, and understanding the function of PinX1 in the regulation of cancers is crucial for improving treatment. In this review, we discuss the expression level of PinX1 in a variety of cancers and how it affects the implicated pathways. Additionally, we outline the function of PinX1 in cancer cells and provide a theoretical basis for PinX1-related cancer therapy. PinX1 has promising prospects in future cancer therapeutics. This review may provide theoretical support for researchers in this field.

Abstract A022: Disrupting redox homeostasis initiates anti-tumor immune responses in pancreatic cancer

Abstract Although immune therapy has made impressive progress in cancer treatment, pancreatic ductal adenocarcinoma (PDAC) remains an exception, likely due to its immunosuppressive tumor microenvironment that prevents immune responses against the tumor. Our current work aims to reactivate the suppressive immune infiltrate using radiation therapy and oxidative stress to potentiate antitumor immune responses in PDAC. Our lab previously found that PDAC cells are dependent on the antioxidant peroxiredoxin-4 (PRDX4) expression. PRDX4 prevents excessive levels of reactive oxygen species in cells and while high PRDX4 expression is associated with a more aggressive disease, it is dispensable in normal tissue. As such, disrupting redox homeostasis by inhibiting PRDX4 represents a targetable vulnerability in cancer cells. To investigate the radio-sensitizing potential of PRDX4, we knocked-down (KD) PRDX4 in human pancreatic tumor cells as well as in mouse cancer cells obtained from the spontaneous KPC model (driven by the KRas and P53 mutations), in combination with radiation. Presence and quantification of DNA damage were performed by immunofluorescence, and impaired cell survival was analyzed by clonogenic assays. Changes in immune secretion were assessed by RT-qPCR and Elisa and in vitro macrophage phenotyping was performed upon exposure to tumor cell conditioned media. Our data so far show an accumulation of cytosolic DNA upon PRDX4 KD in PDAC cells, with the presence of micronuclei as well as less aggregated DNA. Interestingly, targeting PRDX4 before radiation amplifies the release of radiation-induced cytosolic DNA while significantly decreasing cell growth and survival, compared to radiation alone. Cytosolic DNA has been shown to trigger innate immune signaling in tumor cells. Consistently, PRDX4 loss induces the upregulation of many pro-inflammatory genes, including CCL5, CCL20, and CXCL10, in a STING-dependent manner. Combining PRDX4 KD with radiation leads to a higher gene upregulation of these immune stimulatory chemokines, as well as an increased protein secretion within tumor cell media. These findings support an amplified immunomodulatory effect of radiation when combined with PRDX4 loss in PDAC cells. To assess whether targeting PRDX4 can remodel the tumor microenvironment, we applied tumor conditioned media from cancer cells on isolated naive mouse CD45+/CD11c+/F4/80+ macrophages. Media from cells treated with PRDX4 KD + radiation strongly increased the migration ability of macrophages while modulating the expression of a subset of chemokine-encoding genes in immune cells. Using the spontaneous KPC model depleted for PRDX4, along with syngeneic orthotopic models, we are now aiming to confirm this radio-sensitizing and immune-modulatory potential of PRDX4 in vivo. The aggressiveness of PDAC requires research towards novel treatment strategies and our data strongly support evidence for targeting cancer metabolism, particularly antioxidant systems, in synergy with existing cancer therapies, like radiation and immune therapy. Citation Format: Lucie Malbeteau, Emily Poulton, Vishal Pandya, Marianne Koritzinsky. Disrupting redox homeostasis initiates anti-tumor immune responses in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A022.

Psycho-Neuro-EndocrinE-Immunology Therapy of Cancer, Autoimmunity, Geriatric Disorders, Covid-19, and Hypertension.

Despite the great number of experimental investigations in the area of psycho-neuro-endocrine-immunology showing that endocrine, nervous, and immune systems cannot be in vivo physiologically separated, the diagnosis and therapies of the pathologies of these three functional biological systems continue to be separately performed from a clinical practice point of view. The separation between experimental and clinical medicine became dramatic after the discovery of more than 10 human molecules provided by anti-inflammatory and antitumor activity, completely devoid of any toxicity, which may be subdivided into three fundamental classes, consisting of the pineal indole, beta-carboline, and methoxy-kynuramine hormones. Moreover, human systemic diseases, including cancer, autoimmunity, and cardiovascular pathologies, despite their different pathogenesis and symptomatology, are commonly characterized by a progressive decline in the endogenous production of pineal hormones, endocannabinoids, and Ang 1-7, with a consequent inflammatory status and diminished natural resistance against cancer. Then the evaluation of the functional status of the pineal gland, the endocannabinoid system, and ACE2-Ang 1-7 axis should have to be included within the laboratory analyses for the systemic diseases. Finally, the correction of cancer- and autoimmunity-related neuroimmune and neuroendocrine alterations could influence the clinical course of systemic diseases. In fact, preliminary clinical results would demonstrate that the neuroimmune regimen with pineal hormones, cannabinoids, and Ang 1-7 may allow clinical benefits also in patients affected by systemic pathologies, including cancer, autoimmunity, and cardiovascular diseases, who did not respond to the standard therapies.

Carotenoids as modulators of the PI3K/Akt/mTOR pathway: innovative strategies in cancer therapy.

Cancer progression is primarily driven by the uncontrolled activation of cellular signaling pathways, with the PI3K/Akt/mTOR (PAMT) pathway playing a central role. This pathway significantly contributes to the proliferation and survival of cancer cells, and its hyperactivity is a major challenge in managing several types of malignancies. This article delves into the promising potential of carotenoids, natural pigments found in abundance in fruits and vegetables, as a novel therapeutic strategy for cancer treatment. By specifically targeting and inhibiting the PAMT pathway, carotenoids may effectively disrupt the growth and survival of cancer cells. The article examines the complex mechanisms underlying these interactions and highlights the obstacles faced in cancer treatment. It proposes a compelling approach to developing therapies that leverage natural products to target this critical pathway, offering a fresh perspective on cancer treatment. Further research is essential to enhance the therapeutic efficacy of these compounds.