Cytotoxic Therapy Research Articles

Abstract 527: Cancer cells in the resistant, endocycling cell state exhibit centrosome amplification

Abstract Therapy resistance is one of the most common underlying causes of poor prognosis in cancer patients, ultimately driving fatal outcome. We have previous demonstrated that following chemotherapeutic stress, a subset of cancer cells undergo a mitotic skip and enter an endocycle, causing whole-genome duplication without division. This endocycling cell state is resistant to cytotoxic therapies and thus is an actuator of therapy resistance. Cells in the endocycling state eventually undergo depolyploidization and repopulate the tumor, observed clinically as a recurrence. We also demonstrated that the minus-end directed motor protein KIFC1, a mediator of centrosome clustering, has higher expression in cells following treatment. Centrosome amplification (CA) involves aberrations in centrosome number, where cells have 3 centrosomes. Cells with extra centrosomes create a multi-polar spindle during mitosis, which presents high risk for cell death and arrest, but cancer cells with CA avoid this by clustering extra centrosomes to create a pseudo-bipolar spindle. Based upon this data, we hypothesize that studying centrosome dynamics and abnormalities presents a window into better understanding endocycle biology and this novel mechanism of therapy resistance. Cancer cells were treated with LD50 dose of cisplatin and released from treatment for varying lengths of time. CA in endocycling cells increased from 59.2% to 100% during the treatment recovery period while maintaining identical levels of clustering. Endocycling cancer cells have a nearly 5-fold increase in declustered centrosomes compared to proliferative cells. Centrosomes in endocycling cells are displaced from the perinuclear region and toward the cell periphery. We hypothesize that centrosome number may indicate the number of times a cell has endocycled and provide insight into the timing and mechanism of mitotic bypass. Centrosomes play a major role in microtubule nucleation, affecting cell motility and polarity, and act as signaling platforms, enhancing signaling activation and specificity. Because of this, we hypothesize that CA may be a critical mechanism for endocycling cancer cells to survive and maintain this resistant cell state. Citation Format: Madison Purkerson, Sarah Amend, Kenneth J. Pienta. Cancer cells in the resistant, endocycling cell state exhibit centrosome amplification [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 527.

Abstract 7213: Tumor targeted activation of an attenuated exatecan protodrug through Click Chemistry demonstrates efficacy in murine tumor studies

Abstract Shasqi is advancing the Click Activated Protodrugs Against Cancer (CAPAC®) platform based on click chemistry, a Nobel Prize winning technology. The platform is modular and comprises 1) an activator that target specific antigens, and 2) inert cancer drugs, protodrugs, which are selectively activated at tumors via click chemistry. The CAPAC technology separates the tumor targeting function from the payload and re-unites them at the tumor creating the flexibility to optimize activity while limiting toxicity during preclinical and clinical development. The modularity of the platform enables the rapid development of new therapies as well as unlocking unique treatment benefits such as tunable combinations and payload cycling. We envision that CAPAC will expand the scope of potential targets, widen the therapeutic window, and enhance the safety of locally activated cancer therapeutics. Here, we demonstrate the efficacy and safety of our exatecan protodrug (SQP07) used with intratumorally injected activators. The activators, tetrazine-modified sodium hyaluronate biopolymer(s), are injected at the tumor site and followed by a systemic dose of SQP07, a trans-cyclooctene (TCO)-modified protodrug of exatecan (Exa). An efficient covalent reaction between tetrazine and TCO moieties releases active Exa at the tumor. In vitro cytotoxicity studies showed that SQP07 activated with tetrazine was effective against mouse and human tumor cell lines (MC38, CT26, EMT6 and NCI-N87); SQP07 without activator had potency attenuated by 60-133 fold. In vivo tumor distribution and activity of SQP07 with the intratumoral biopolymer activators was evaluated in an NCI-N87 gastric cancer xenograft model. Female C.B-17 SCID mice received a single intravenous dose of vehicle (10% HPCD), Exa (50 mg/kg) or biopolymer (40 or 100 μL intratumorally) followed by SQP07 or SQP07 alone (50 mg/kg Exa mol equivalent). 1 hour after biopolymer + SQP07 treatment, activated Exa was highly concentrated in the tumor and stroma. This led to tumor regression in animals up to 40 days, performing significantly better than the free drug cytotoxic, Exa alone. Similarly, median survival with biopolymer + SQP07 was higher (>81 days) compared to Exa (68.5 days). Toxicity, measured as body weight loss, was comparable (~5%) and transient between Exa and biopolymer + SQP07. SQP07 alone treatment without the biopolymer was not differentiated from the vehicle control. These data show that the CAPAC platform, which separates the targeting agent from the payload, is an effective way to administer cytotoxic therapies systemically. Additional work with other tumor models, different biopolymers and the SQP07 protodrug is ongoing. Citation Format: Sangeetha Srinivasan, Stefanie Wagner, George Coricor, Tri-Hung Nguyen, Jesse M. McFarland, José M. Mejía Oneto. Tumor targeted activation of an attenuated exatecan protodrug through Click Chemistry demonstrates efficacy in murine tumor studies [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 7213.

Abstract 3878: Therapy-associated remodeling of pancreatic cancer revealed by single-cell spatial transcriptomics and optimal transport analysis

Abstract The aggressive nature of pancreatic ductal adenocarcinoma (PDAC) is driven by cell-intrinsic features and cell-extrinsic interactions between tumor cells and the desmoplastic stroma, which is infiltrated with heterogeneous populations of cancer-associated-fibroblasts (CAFs) and immune cells. These features are able to drive emergent properties such as chemoresistance through diverse and not yet fully elucidated mechanisms. Through single-nucleus RNA-seq and whole-transcriptome digital spatial profiling of PDAC patient tumors, we previously reported marked heterogeneity in the malignant cells and CAF composition of PDAC. In this project, we performed high-plex single-cell spatial molecular imaging (990-plex SMI, Nanostring) to dissect the therapy-remodeled multicellular neighborhoods and malignant-stroma cell interactions in primary resected human pancreatic cancer with (n = 6) or without (n = 7) neoadjuvant chemotherapy and radiotherapy. SMI of the PDAC samples yielded ~753,000 high-confidence single cells and captured the heterogeneity of malignant cells and CAFs. We identified three malignant subtypes: classical (CLS), basal-like (BSL), and the recently characterized neural-like progenitor (NRP) malignant subtype that exhibits stem-like and neurodevelopmental features. To leverage the single-cell spatial resolution of SMI to further dissect treatment-associated changes in cell-cell interactions, we developed Spatially Constrained Optimal Transport Interaction Analysis (SCOTIA), an optimal transport model with a cost function that includes both spatial distance and ligand-receptor gene expression. Our results uncovered a marked enrichment in ligand-receptor interactions between CAFs and malignant cells in response to treatment. In combination with several complementary methods, including examination of downstream target gene expression and ex vivo 3D co-culture of CAF and PDAC cells, we found that IL-6 family signaling was the most consistently enriched interaction between CAFs and malignant cells after treatment. This led us to hypothesize that IL-6 signaling between CAFs and malignant cells may induce chemoresistance in cancer cells. To test this hypothesis, we treated three human cancer cell lines (AsPC1, Panc1, Panc0203) with 5FU with or without IL-6 and discovered that IL-6 induced chemoresistance for two of the lines (Panc1, Panc0203). Taken together, we have integrated novel experimental and computational approaches to enable high-resolution, spatially-guided discovery of treatment-associated remodeling in the pancreatic cancer microenvironment. Further studies will be conducted to dissect additional mechanisms by which candidate cell-cell interactions promote disease progression and/or resistance to cytotoxic therapy, with the ultimate goal of guiding novel therapeutic development. Citation Format: JINGYI CAO, Carina Shiau, Dennis Gong, Mark T. Gregory, Xunqin Yin, Jae-Won Cho, Peter L. Wang, Jennifer Su, Jason W. Reeves, Jimmy A. Guo, Nicole A. Lester, Jung Woo Bae, Ryan Zhao, Martin Hemberg, William L. Hwang. Therapy-associated remodeling of pancreatic cancer revealed by single-cell spatial transcriptomics and optimal transport analysis [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 3878.

Abstract 4607: Targeted nanoparticle delivery of irinotecan and Ewing sarcoma-specific siRNA is an effective combination therapy for Ewing sarcoma

Abstract Background: Ewing sarcoma (ES) is an aggressive bone and soft tissue tumor affecting children and adolescents with an overall survival rate of 50%. Irinotecan (IR) is an effective chemotherapeutic agent but is associated with significant toxicity. Using an anti-CD99 targeted hybrid polymerized lipid nanoparticle containing IR, NV103, in pre-clinical mouse xenograft model of the disease, tumor ablation was achieved at 2mg/kg of IR versus 50mg/kg for free IR. All ES harbor a chromosomal translocation resulting in expression of a fusion EWS-FLI1 protein or equivalent. This chimeric gene is a transcriptional regulator that upregulates the FEZF1 and FEZF1-AS1 genes. Both EWS-FLI1 and FEZF1-AS1 genes are unique to ES and are not expressed in normal adult tissues. EWS-FLI1 promotes cell growth while the FEZF1-AS1 complex promotes tumor metastasis, a hallmark of ES. In vitro RNAi targeting of EF and FEZF1-AS1 results in tumor cell death. We hypothesized that combining EWS-FLI1 and/or FEZF1-AS1 targeted RNAi therapy with NV103 cytotoxic therapy would be more effective than any single modality therapy. Methods: NV103 was provided by NanoValent Pharmaceuticals. siRNA containing lipid nanoparticles (LNP-siRNA) were generated using PreciGenome NanoGenerator. siRNA was quantified using the ribogreen assay. Nanoparticles were analyzed for size and particle numbers by NanoSight. siRNA was used to target the following genes- EWS-FLI1, FEZF1, FEZF1-AS1, or GFP. A673 cells expressing GFP were used for this in vitro study. Various doses of IR and siRNA were used in combination and cell growth/death was imaged live using Incucyte. ATP assay was used to confirm live cells and to determine minimum effective dose (MED) over 72 hours of treatment. Results: LNP-siRNA, mean diameter 70nm and PDI<0.2, encapsulated 90% of the siRNA in solution. LNP are stable at 4°C for at least 4 weeks with minimal-to-no loss of activity. NV103 had a MED of 1µM. MED of various siRNA was 30 to 50nM. Combination of NV103 and LNP-siRNA reduced MED of IR to 250nM. One treatment dose of LNP-siRNA followed by NV103 treatment three days later maintained significant cell death over 10 days post treatment initiation. Control cells were 97% more confluent than NV103/EWS-FLI1 siRNA treated ones, 85% more than NV103/FEZF1 siRNA cells and 92% more than NV103/FEZF1-AS1 treated cells. siRNA combinations of EWS-FLI1 and FEZF1 or FEZF1-AS1 along with NV103 added no further benefit. Conclusion: Combination nanoparticle therapy of IR and ES-specific siRNA reduces IR MED by four-fold. LNP delivery of siRNA enables tumor-specific gene targeting. Most have no available small molecule therapy. Targeting ES cells with both a low dose (250nM) of IR and 30-50nM of siRNA against unique tumor biomarkers results in increased cell death with no IR toxicity. Further animal studies are required to determine the effectiveness of such therapy in vivo. Citation Format: Sheetal A. Mitra, Jean-Hugues Parmentier, Hyung-Gyoo Kang, Timothy J. Triche. Targeted nanoparticle delivery of irinotecan and Ewing sarcoma-specific siRNA is an effective combination therapy for Ewing sarcoma [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 4607.

Abstract 3470: Evaluation of the association between sickle cell disease and breast cancer using the All of Us Research Program dataset

Abstract Background: The All of Us Research Program (AoURP) dataset was used to evaluate pharmacological treatment modalities in patients with both breast cancer (BC) and sickle cell disease (SCD). This study aims to identify treatment strategies for sickle cell patients with BC that may inform improved treatment options for patients living with either or both conditions, as there is an imminent need in this patient population. Methods: We investigated the relationship between SCD and BC using the AoURP dataset. Criteria were female patients with a confirmed diagnosis of concomitant SCD and BC were selected. Hematologic, antineoplastics, and immunomodulating agents prescribed to patients were identified. Analysis was conducted in a Jupyter Notebook environment by way of R. Using FDA-approved and off-label indications, medication use patterns were used to reverse-engineer patient information and identify trends between SCD and BC. Results: Nine female patients had concomitant diagnoses of SCD and BC, which aligned with the inclusion criteria. African Americans were significantly represented in this cohort, making up sixty-seven of patients. Twenty-two percent of patients did not indicate race, while eleven percent of patients identified as Caucasian. All patients included in the study were prescribed anemic therapy. Eleven percent of patients were prescribed an FDA-approved medication for SCD. Seventy-eight percent of patients were prescribed hormone-targeted BC medications. Thirty-three percent of patients were prescribed the immunotherapy regimen, Dinutuximab with adjunctive interferon-alpha. Eleven percent of patients were prescribed cytotoxic therapy. Conclusion: Further investigation is warranted for dinutuximab use in BC treatment, specifically the triple negative subtype, as currently no targeted therapeutic options exist, and prognosis is poor. The data suggests dinutuximab with adjunctive interferon-alpha may be promising for triple-negative BC patients with SCD. Citation Format: Ivan T. Jubilee, Lauren K. Evans, KiTani Parker Lemieux. Evaluation of the association between sickle cell disease and breast cancer using the All of Us Research Program dataset [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 3470.

Abstract 5998: Pharmacological inhibition of the LIF-LIFR autocrine loop reveals vulnerability of ovarian cancer to ferroptosis

Abstract Introduction: Of all gynecologic cancers, epithelial ovarian cancer (OCa) stands out with the highest mortality rates. Despite all efforts, 90% of individuals who receive standard surgical and cytotoxic therapy experience disease recurrence. The potential involvement of leukemia inhibitory factor (LIF) and its receptor (LIFR) in the progression of OCa is still obscure. In this study, we examined the mechanisms by which disruption of LIF/LIFR autocrine loops contributes to the cell death of ovarian cancer cells. Methods: The expression profiles of LIF and LIFR were obtained using 24 distinct OCa model cells, comprising both primary and established cell lines. The effects of EC359 on OCa cells were evaluated using reporter assays, colony formation, cell death, and cell viability. Flow cytometry was utilized to analyze lipid peroxidation. The Agilent Seahorse XF Pro Analyzer was used to calculate the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Furthermore, flow cytometry was used for the preparation and analysis of lymphocytes. Mechanistic investigations were performed with RT-qPCR and RNA-seq analysis. The efficacy of the LIFR inhibitor EC359 as a targeted therapy was investigated using cell-based xenografts, syngeneic xenografts, patient-derived organoids (PDO), and patient-derived xenograft (PDX) models. Results: Analysis of cancer databases revealed that elevated expression of LIF or LIFR was associated with poor progression-free survival of OCa patients and a predictor of poor response to chemotherapy. Using 24 different primary and established OCa cell lines that represent four subtypes of epithelial OCa, we demonstrated that LIF/LIFR autocrine signaling is active in OCa. Moreover, treatment with EC359, a novel LIFR inhibitor, significantly reduced OCa cell viability and cell survival with an IC50 ranging from 5 to 50 nM. Furthermore, EC359 diminished the stemness of OCa cells. Mechanistic studies using RNA-seq and rescue experiments unveiled that EC359 primarily induced ferroptosis by suppressing the glutathione antioxidant defense system. Using multiple in vitro, ex vivo, and in vivo models including organoids, cell-based xenografts, patient-derived explants, and xenograft tumors, we demonstrated that EC359 dramatically reduced the growth and progression of OCa. Additionally, EC359 therapy considerably improved tumor immunogenicity by robust CD45+ leukocyte tumor infiltration and polarizing tumor-associated macrophages (TAMs) toward M1 phenotype while showing no impact on normal T-, B-, and other immune cells. Conclusions: Collectively, our findings indicate that the LIF/LIFR autocrine loop plays an essential role in OCa progression and that EC359 could be a promising therapeutic agent for OCa. Citation Format: Behnam Ebrahimi, Suryavathi Viswanadhapalli, Uday P. Pratap, Rahul Gopalam, Xue Yang, Prabhakar P. Venkata, Viktor Drel, Bindu Santhamma, Swapna Konda, Xiaonan Li, Alondra L. Rodriguez Sanchez, Hui Yan, Gangadhara R. Sareddy, Zhenming Xu, Brij B. Singh, Philip T. Valente, Yidong Chen, Zhao Lai, Manjeet Rao, Edward R. Kost, Tyler Curiel, Rajeshwar R. Tekmal, Hareesh B. Nair, Ratna K. Vadlamudi. Pharmacological inhibition of the LIF-LIFR autocrine loop reveals vulnerability of ovarian cancer to ferroptosis [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 5998.

Abstract 2783: The exosomes from cord blood stem cells, containing novel miRNAs, induce apoptosis in melanoma cells and enhance T cell anticancer function

Abstract Regulatory T (Treg) cells expressing FOXP3 play a critical role in suppressing immune responses against anti-tumor immune responses. However, their presence in tumor tissues is often associated with poor prognosis. Cord blood stem cell-derived exosome vesicles (CBSC-EV) constitute a valuable source of lipids, microRNAs, and proteins, that are essential for cell-to-cell communication and provide therapeutic benefits. This study aimed to investigate the contents of CBSC-EV, identifying several known miRNAs (from Let7 and Let5 families) and two unknown miRNAs. Healthy lymphocytes, fibroblasts, and CHL1 amelanotic melanoma cell lines were transfected with these two novel miRNA inhibitors, and the changes before and after treatment compared to CBSC-EV and H2O2 were examined. Following treatment, the cells underwent a 24-hour incubation period, during which the level of cytotoxicity was assessed using CCK8, and the degree of DNA damage incurred was quantified with the Fast Microplate DNA damage assay. To further investigate the effects of treatment, RNA sequencing was conducted on both healthy and cancerous cells. The results demonstrated that CBSC-EV and novel miRNAs induced cytotoxicity in cancer cells, while in healthy cells, the DNA damage was repaired and cell viability was significantly increased (p<0.001). RNA sequencing revealed that following treatment with CBSC-EV and both CBSC-EV+N1 and N2 inhibitors in malignant melanoma cells, the expression of genes involved in the cytokine-mediated signaling pathway, cytokine-cytokine interaction, and cytokine activity were enhanced. In healthy cells treated with CBSC-EV and novel miRNA inhibitor transfection, the MT-CO1 gene was upregulated, contributing to cytochrome-c oxidase activity. This study presents evidence of the potential use of novel miRNAs as genetic material for cancer therapeutics in the future. Additionally, the findings suggest that these miRNAs could be used as an immune system modulator against melanoma. These findings demonstrate that miRNAs can effectively suppress resistance to anticancer cytotoxic therapy, which is a common feature of cancer cells. This suggests that miRNAs can potentially enhance current cancer therapies. Citation Format: Mojgan Mojgan Najafzadeh, Adi Baumgartner, Shohreh Jafarinejad, Zahra Karimi, Mohammad Isreb, Pouria Akhbari, Nader Ghaderi, Farshid Sefat, Saeed Heidari Keshel, Parisa Naeem, Rojan Ghaderi, Jacobo Elis Gomez, Diana Anderson, Andrew Wright. The exosomes from cord blood stem cells, containing novel miRNAs, induce apoptosis in melanoma cells and enhance T cell anticancer function [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 2783.

Origins of Second Malignancies in Children and Mutational Footprint of Chemotherapy in Normal Tissues.

Using whole-genome and error-correcting ultra-deep duplex sequencing, we uncover different origins for second neoplasms in four children. We also uncover the presence of platinum-related mutations across 10 normal tissues of exposed individuals, highlighting the impact that the use of cytotoxic therapies may have on cancer survivors. See related commentary by Pacyna and Nangalia, p. 900. This article is featured in Selected Articles from This Issue, p. 897.

Mathematical modelling of clonal reduction therapeutic strategies in acute myeloid leukemia

Over the years, the overall survival of older patients diagnosed with acute myeloid leukemia (AML) has not significantly increased. Although standard cytotoxic therapies that rapidly eliminate dividing myeloblasts are used to induce remission, relapse can occur due to surviving therapy-resistant leukemic stem cells (LSCs). Hence, anti-LSC strategies have become a key target to cure AML. We have recently shown that previously approved cardiac glycosides and glucocorticoids target LSC-enriched CD34+ cells in the primary human AML 8227 model with more efficacy than normal hematopoietic stem cells (HSCs). To translate these in vitro findings into humans, we developed a mathematical model of stem cell dynamics that describes the stochastic evolution of LSCs in AML post-standard-of-care. To this, we integrated population pharmacokinetic-pharmacodynamic (PKPD) models to investigate the clonal reduction potential of several promising candidate drugs in comparison to cytarabine, which is commonly used in high doses for consolidation therapy in AML patients. Our results suggest that cardiac glycosides (proscillaridin A, digoxin and ouabain) and glucocorticoids (budesonide and mometasone) reduce the expansion of LSCs through a decrease in their viability. While our model predicts that effective doses of cardiac glycosides are potentially too toxic to use in patients, simulations show the possibility of mometasone to prevent relapse through the glucocorticoid’s ability to drastically reduce LSC population size. This work therefore highlights the prospect of these treatments for anti-LSC strategies and underlines the use of quantitative approaches to preclinical drug translation in AML.

Low-Dose Sorafenib Promotes Cancer Stem Cell Expansion and Accelerated Tumor Progression in Soft Tissue Sarcomas.

The cancer stem cell (CSC) hypothesis postulates that heterogeneous human cancers harbor a population of stem-like cells which are resistant to cytotoxic therapies, thus providing a reservoir of relapse following conventional therapies like chemotherapy and radiation (RT). CSCs have been observed in multiple human cancers, and their presence has been correlated with worse clinical outcomes. Here, we sought to evaluate the impact of drug dosing of the multi-tyrosine kinase inhibitor, sorafenib, on CSC and non-CSCs in soft tissue sarcoma (STS) models, hypothesizing differential effects of sorafenib based on dose and target cell population. In vitro, human cancer cell lines and primary STS from surgical specimens were exposed to escalating doses of sorafenib to determine cell viability and expression of CSC marker aldehyde dehydrogenase (ALDH). In vivo, ALDHbright CSCs were isolated, exposed to sorafenib, and xenograft growth and survival analyses were performed. We observed that sarcoma CSCs appear to paradoxically respond to the tyrosine kinase inhibitor sorafenib at low doses with increased proliferation and stem-like function of CSCs, whereas anti-viability effects dominated at higher doses. Importantly, STS patients receiving neoadjuvant sorafenib and RT on a clinical trial (NCT00864032) showed increased CSCs post therapy, and higher ALDH scores post therapy were associated with worse metastasis-free survival. These data suggest that low-dose sorafenib may promote the CSC phenotype in STS with clinically significant effects, including increased tumor growth and higher rates of metastasis formation in sarcoma patients.

Multiple Primary Cancers With Hematologic Malignancies and Germline Predisposition: A Case Series.

The term "multiple primary (MP) cancers" refers to the existence of more than one cancer in the same patient. The combination of MP cancers with hematological malignancies is relatively uncommon. In this study, we present five patients diagnosed with MP cancers concomitant with hematological malignancies. We comprehensively analyzed their clinical characteristics, cytogenetic profiles, and germline and somatic variants. As first primaries, two patients had solid cancer not followed by cytotoxic therapy and three had hematologic cancer, followed by cytotoxic therapy. The second primaries were all hematologic malignancies that did not meet the criteria for therapy-related myeloid neoplasm. Notably, two (40%) out of the five patients harbored pathogenic potential/presumed germline variants in cancer predisposition genes. Therefore, germline variant testing should be considered when MP cancers with hematological malignancies require consideration for related donor stem cell transplantation.

Abstract PR-004: Targeting EPHB2/ABL1 restores anti-tumor immunity in a preclinical model of ependymoma

Abstract Purpose: Ependymoma (EPN) is a common type of brain tumor in children and is often resistant to available cytotoxic therapies. Molecular profiling studies have led to a better understanding of unique EPN subtypes and revealed a critical role of EPHB2. However, the immune system's role in tumor progression and treatment response remains poorly understood. New treatments for EPN are desperately needed and should be developed in a molecular subtype-specific fashion. Experimental Design: We developed a syngeneic mouse model using subtype-specific EPHB2-driven genetically engineered EPN tumor cells. Druggable targets were identified by matching transcriptomic signatures with the target spectrum of FDA-approved drugs. After identifying dasatinib as a potentially effective agent, we measured the changes in the immune microenvironment during EPN growth and after dasatinib treatment. Results: Transcriptomic profiling of EPHB2-driven EPN and analysis of a human EPN dataset revealed multiple protein kinases as potential druggable targets. We found that the multikinase inhibitor dasatinib potently inhibited the growth of EPN both in vitro and in vivo, mainly through blocking EPHB2 and ABL1 signaling. We found an increased frequency of immunosuppressive M2-like tumor-associated macrophages (TAMs), which proportionally increased with tumor size during tumor progression. However, treatment with dasatinib reprogrammed the EPN immune microenvironment by polarizing the TAMs toward an anti-tumor M1-like phenotype and increasing CD8 T cell activation. Furthermore, dasatinib treatment induced complete regression of established EPN tumors in 78% of the animals and protected survivors against tumor recurrence. Depletion of CD8 T cells compromised the durability of EPN responses and reduced overall survival. Conclusions: These data indicate that dasatinib may be an effective therapy for EPHB2-driven molecular subgroup of EPNs by activating the anti-tumor immune response and support further investigations of dasatinib in clinical trials. Citation Format: Taylor P. Uccello, Jun Ren, Zohreh Amoozgar, Yuhui Zhao, Pin-Ji Lei, William W. Ho, Sylvie Roberge, Peigen Huang, Dan G. Duda, Lei Xu, Rakesh K. Jain. Targeting EPHB2/ABL1 restores anti-tumor immunity in a preclinical model of ependymoma [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr PR-004.

Utility and impact of quantitative pharmacology on dose selection and clinical development of immuno-oncology therapy.

Immuno-oncology (IO) therapies have changed the cancer treatment landscape. Immune checkpoint inhibitors (ICIs) have improved overall survival in 20-40% of patients with malignancies that were previously refractory. Due to the uniqueness in biology, modalities and patient responses, drug development strategies for IO differed from that traditionally used for cytotoxic and target therapies in oncology, and quantitative pharmacology utilizing modeling approach can be applied in all phases of the development process. In this review, we used case studies to showcase how various modeling methodologies were applied from translational science and dose selection through to label change, using examples that included anti-programmed-death-1 (anti-PD-1), anti-programmed-death ligand-1 (anti-PD-L1), anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4), and anti-glucocorticoid-induced tumor necrosis factor receptor-related protein (anti-GITR) antibodies. How these approaches were utilized to support phase I-III dose selection, the design of phase III trials, and regulatory decisions on label change are discussed to illustrate development strategies. Model-based quantitative approaches have positively impacted IO drug development, and a better understanding of the biology and exposure-response relationship may benefit the development and optimization of new IO therapies.

Psychosis Due to Osmotic (Pontine) Myelinolysis in Non-Hodgkin’s Lymphoma: Case Report

Introduction: central pontine myelinolysis (CPM) is rare neurological condition. The severe symptoms of neurologic and psychiatric disorders accompanying this condition are not sufficiently disclosed in the literature. Most often CPM develops on infusion therapy and forced correction of hyponatremia. The complexity of diagnosis and the lack of certain algorithms for the management of this category of patients cause a high frequency of disability, persistent neurological and psychiatric symptoms, and lethal outcomes.The aim was to present and analyze clinical picture of psychosis in CPM on the example of non-Hodgkin’s lymphoma case report. Patient and method: clinical analysis of disorders in 14-years old patient with diagnosis of non-Hodgkin’s lymphoma.Results: clinical polymorphism of psychotic features, catatonic disorders, neurological symptoms at the end stage and development of psychosis associated with CPM during cytotoxic treatment. A year and a half follow-up of the first generation antipsychotics administration is presented.Conclusion: CPM may occur on cytotoxic infusion therapy in patients with non-Hodgkin’s lymphoma and be accompanied by severe psychotic disorders. Thus, practitioners should be aware of the risks of this condition, its diagnostic and therapeutic options when working with these patients.

New Insights into Chemoresistance Mediated by Mdm2 Inhibitors: The Benefits of Targeted Therapy over Common Cytostatics.

The inhibition of the Mdm2-p53 protein-protein interaction is a promising strategy for anticancer therapy. However, the problem of developing secondary chemoresistance in tumors treated with such drugs has not yet been sufficiently studied. In this work, we compared the properties of a drug-resistant cell line obtained during long-term cultivation in the presence of an Mdm2 inhibitor, Nutlin-3a, with a similarly obtained line insensitive to the cytostatic drug paclitaxel. We first confirmed the higher safety levels of Mdm2 inhibitors when compared with cytostatics in terms of the development of secondary chemoresistance. We showed that Nutlin-3a affects both the targeted p53-mediated cellular machinery and the universal ABC-mediated efflux mechanism. While both targeted and general defense mechanisms are activated by the Mdm2 inhibitor, it still increases the susceptibility of tumor cells to other drugs. The results obtained indicate that the risks of developing chemoresistance under the therapy with a targeted agent are fundamentally lower than during cytotoxic therapy.

Role of microRNA in Sex Steroid Hormones Signaling and Its Effect in Regulation of Endometrial, Ovarian, and Cervical Cancer: A Literature Review.

Worldwide, in 2020, an estimated 417,367 people were diagnosed with uterine cancer. Endometrial cancer accounts for more than 90% of all uterine cancers. The 15th most frequent cancer overall and the sixth most frequent cancer in women is endometrial cancer. Global ovarian cancer Incidence was diagnosed estimated at 313,959 new cases worldwide in 2020. Cervical cancer is the fourth most common malignancy in women worldwide. It has been demonstrated that sex steroid hormones (SSHs) have an essential role in regulating the susceptibility of cancer to cytotoxic therapy. Dysregulation of DNA repair contributes to genomic instability, aberrant cell survival, and cancer development as well as therapy resistance. Several crucial DNA repair components have been discovered to interact with the three main SSHs: androgen, estrogen, and progesterone. MicroRNA (miRNA) dysregulation has been associated with aberrant sex steroid hormone signaling as well as an increased risk of endometrial, cervical, and ovarian cancer. The expression of estrogen and progesterone receptors is modulated by a number of miRNAs, and it has been demonstrated that the miRNA expression profile may predict the way a patient would respond to hormone therapy. Additionally, particular miRNAs have been linked to the control of genes involved in signaling pathways connected to hormones. Recent research has shown that miRNAs can modify hormone signaling pathways and affect the expression of sex steroid hormone receptors. Our goal in this literature review is to present an overview of current knowledge regarding the role of miRNAs in cancers regulated by sex steroid hormone pathways, as well as to identify particular miRNA targets for hormonal therapy.

Scalp hypothermia for the prevention of chemotherapy-induced alopecia in breast cancer

Background. Breast cancer (BC) is a socially significant disease in women all over the world, ranking 1st in the structure and 5th in the number of deaths. Polychemotherapy in the complex treatment of BC accounts for approximately 80%. The main side effect that significantly affects the quality of life is alopecia, which occurs on average in 65% of patients.
 Aim. To evaluate the efficacy and tolerability of scalp hypothermia (SHT) for the prevention of chemotherapy-induced alopecia in patients with BC.
 Materials and methods. From June 2016 to September 2023, 75 patients with a median age of 44.1 years with stage I–IV BC were observed. All patients received cytotoxic therapy at various stages of treatment. To prevent alopecia, local SHT was used using an Orbis II device (Paxman Coolers, United Kingdom).
 Results. Stage I of the disease was observed in 18 (24%) patients, stage II in 22 (29.3%), stage III in 30 (40%), and stage IV in 5 (6.7%). Patients received 5 different neo- and adjuvant regimens of polychemotherapy. Taxane-containing combined regimens prevailed. 364 SHT sessions (4–8 sessions per patient) were performed; 48 (64%) patients received the procedure in full. Complete hair preservation was achieved in 43 (57.3%) patients. Grade 1 alopecia was observed in 19 (25.4%) patients and grade 2 in 9 (12%) patients. Of the 5 patients with advanced BC, grade 2 alopecia was reported in 1 patient, grade 3 in 3, and grade 4 in 1. Side effects were reported in 16% of cases; the most common were a feeling of cold and a slight headache. Due to the intolerance of the cold helmet, 3 patients refused to use it. No scalp metastases were observed during the follow-up. During the procedure, almost all patients noted a high level of comfort.
 Conclusion. Local SHT is an effective method of preventing cytotoxic therapy-induced alopecia in patients with BC. It improves the psychological and social adaptation of patients.

Effectiveness and safety of empegfilgrastim (Extimia®, BIOCAD) in patients with lymphoproliferative diseases receiving cytotoxic therapy: results of LEGERITY, a multicenter retrospective-and-prospective observational post-marketing study

Aim. To evaluate the effectiveness and safety of Extimia® BIOCAD (international non-proprietary name: empegfilgrastim) to reduce the incidence and duration of neutropenia, the incidence of febrile neutropenia (FN) and infections associated with FN in patients with lymphoproliferative diseases receiving myelosuppressive therapy.
 Materials and methods. The paper presents the results of a multicenter retrospective-and-prospective observational post-marketing study of the safety and effectiveness of Extimia® BIOCAD (international non-proprietary name: empegfilgrastim) in patients with lymphoproliferative diseases receiving cytotoxic therapy. Initially, the study was defined as retrospective-and-prospective. However, only 2 of 671 (0.3%) patients were included retrospectively. Thus, the study is based on the evaluation of prospectively collected data. The analysis describes the characteristics and treatment of 671 patients diagnosed with lymphoma who received one or more cycles of chemotherapy in the LEGERITY study. The endpoints of interest included the incidence of grade 3–4 neutropenia, FN, and grade 3–4 infectious complications, the frequency of antibiotic therapy, and the incidence of all adverse reactions in patients who received at least one dose of the study medication.
 Results. A total of 671 patients were enrolled in the study, the majority having B-cell non-Hodgkin lymphoma (428/671, 64%) and Hodgkin lymphoma (211/671, 31%). The mean age was 54 years (18–84); 35% (236/671) of patients were elderly (over 60). The number of injections of empegfilgrastim for the entire observation period was 3093 (n=671). Adverse events were reported in 57/3093 (1.8%) cases. The most common adverse events were mild to moderate ossalgia and myalgia (27/671, 4%), back pain, and arthralgia (12/671, 1.8%), which did not require drug therapy. Two patients developed serious adverse reactions – CTCAE v.5 grade 4 hypotension events. 529 (78.8%) patients received at least 4 courses of chemotherapy. FN was reported in 14 (2.6%) patients and did not require antimicrobial therapy.
 Conclusion. The final analysis results confirm the high clinical efficacy and safety of the Russian original pegylated granulocyte colony-stimulating factor empegfilgrastim (Extimia®) in patients with indolent and aggressive lymphomas. The data obtained from real-world clinical practice demonstrate a favorable safety and tolerability profile of empegfilgrastim in all age groups, including the elderly population.

Treatment of Pediatric Acute Lymphoblastic Leukemia: A Historical Perspective.

Acute lymphoblastic leukemia (ALL) is the most common disease in pediatric oncology. The history of developmental therapeutics for ALL began in the 1960s with the repetition of "unreliable" medical interventions against this lethal disease. By the 1990s, the development of multi-agent chemotherapy and various types of supportive care rendered ALL treatable. Highly sophisticated, molecular, diagnostic techniques have enabled highly accurate prediction of the relapse risk, and the application of risk-adapted treatments has increased the survival rate in the standard-risk group to nearly 100% in most European nations and North America. Incorporation of state-of-the-art, molecularly targeted agents and novel treatments, including cell and immunotherapy, is further improving outcomes even in the high-risk group. On the other hand, the financial burden of treating children with ALL has increased, imperiling the availability of these diagnostic and treatment strategies to patients in low- and middle-income countries (LMICs). The fundamental treatment strategy, consisting of corticosteroid and classical cytotoxic therapy, has achieved fairly good outcomes and should be feasible in LMICs as well. The present review will discuss the history of developmental therapeutics for childhood ALL in various countries through an extensive literature review with the aim of proposing a model for a treatment backbone for pediatric ALL. The discussion will hopefully benefit LMICs and be useful as a base for future clinical trials of novel treatments.

Acute Myeloid Leukemia Post Cytotoxic Therapy in Breast Cancer Survivors-Over 23 Years of Single Center Analysis.

Background: Acute myeloid leukemia post cytotoxic therapy (AML-pCT) among breast cancer (BC) survivors represents a life-threatening complication. This study aims to assess the clinical outcomes of AML-pCT post BC. Methods: An analysis of all AML patients treated at a single hematology center (2000-2023) was performed to select patients with AML-pCT post BC. We applied the 2022 ELN criteria to define the genetic risk. Results: Among 847 AML patients, 28 were diagnosed with AML-pCT following BC. Complex karyotype (CK) occurred in 23.8% of patients. The median overall survival (OS) was 40 months. The survival outcomes were better after allogenic hematopoietic stem cell transplantation (alloHCT) treatment compared to chemotherapy alone (median OS: 47 versus 7 months, p = 0.008). Patients demonstrating CK showed lower survival compared to those without CK (2-year OS: 25.0% versus 66.2%, p = 0.0048). The multivariable Cox proportional hazards regression model indicated that treatment with alloHCT emerged as a significant factor associated with improved OS. The treatment was associated with superior OS (HR = 0.07, 95% CI = 0.01-0.86, p = 0.04). Conclusions: Patients with AML-pCT following BC were characterized with the highest frequency of adverse genetic risk profiles and demonstrated worse survival rates. AlloHCT should be performed as early as possible in such patients. The growing need for studies on inherited cancer susceptibility underscores the importance of close AML-pCT development monitoring in BC survivors.