Abstract Anthracyclines such as doxorubicin (dox) are effective chemotherapeutic agents frequently used in adolescents and young adults (AYAs) with cancer but are associated with cardiotoxicity. Mitigation of cardiac late effects through modifiable behaviors has global and cost-effective benefits, but parameters influencing potential benefit remain unclear. Here, we investigated the impact of sucrose consumption on dox-induced cardiotoxicity and senescence in vivo. Male and female p16/3MR transgenic mice were provided normal (NSW, 0%) or high (HSW, 45%) sucrose water and treated with dox (2.5 mg/kg, tail vein ×4 doses). Cardiac function was assessed by echocardiography to measure ejection fraction (EF) and fractional shortening (FS). Cardiac miR-1a and miR-499 expression were quantified by qRT-PCR, and senescent cell accumulation was visualized in heart tissue by red fluorescent protein (RFP) signal. High sucrose intake worsened dox-associated reductions in ejection fraction, with the HSW + dox group showing the greatest functional decline, a pattern that was statistically significant at 4 weeks (p = 0.0187) and 6 weeks (p = 0.0353) post-treatment. Notably, high sucrose alone reduced EF relative to NSW controls, indicating diet-induced impairment of cardiac function. Dox treatment elevated biomarkers of myocardial stress (miR-1a and miR-499) in cardiac tissue, and high sucrose alone produced comparable upregulation. Senescence, as measured by RFP fluorescence, increased in both dox- and sucrose-exposed hearts. Interestingly, the HSW + dox group demonstrated the highest RFP signal, compared to both dox and diet controls, indicating a synergistic enhancement of senescence, suggesting that molecular senescence markers may capture early injury preceding functional decline. High dietary sucrose both amplifies and independently impairs cardiac function and increases senescence, with combined sucrose and dox exposure promoting the strongest EF reduction and senescence elevation. These findings underscore the contribution of sucrose consumption to anthracycline-associated cardiac injury and support the investigation of dietary modulation as a potential strategy to mitigate long-term cardiac damage. Citation Format: Alaina L. Poche, Huaxian Ma, Prince Jeyabal, Fei Wang, Efstratios Koutroumpakis, Eugenie S. Kleinerman, Joya Chandra. High sucrose intake amplifies and independently promotes anthracycline-induced cardiac dysfunction and senescence in juvenile mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 932.

Adolescent and young adults (AYAs) with sarcoma and our mouse model were used to evaluate early and late effects of doxorubicin (Dox) on skeletal muscle and the impact of physical activity on preventing Dox-induced damage. Skeletal muscle changes in 46 AYAs were quantified using computed tomography scans pre- and post- high-dose Dox treatment. Physical activity was monitored via wearable device. Patient blood samples were analyzed for myo-miRNA changes. In mice, we analyzed acute and late effects of Dox vs. Dox + exercise on skeletal muscle histology, Z-disc morphology, collagen deposition, changes in IL-6 and myo-miRNA, and changes in blood flow. During chemotherapy, AYA patients had poor physical activity levels and experienced an average muscle area and density reduction of -13.2% ± 10.9% (p < 0.01) and − 10.9% ± 25.6% (p = 0.01), respectively. In mice, there was an increase in number of abnormal mitochondria, autophagosomes, and disruption in Z-discs in the hindlimb at both 2 and 12-weeks post Dox. In patients and mice, miR-133b, miR-206, and miR-126 significantly decreased after Dox exposure. In the mouse model, exercise prevented all Dox-induced morphologic changes and acute Dox-induced decrease in muscle blood flow. Dox therapy resulted in skeletal muscle loss and reduction in muscle-specific miRNAs (miR-133b, 206, and 126) in plasma from mice and AYA patients, as well as in mouse muscle tissue. Changes in muscle morphology were not seen in mice that exercised, thus indicating the potential use of exercise as an intervention to prevent Dox-induced muscle damage.

BackgroundThere is a growing interest in characterizing the relationship between long-term physical activity (PA) habits and cancer-related outcomes such as treatment-related toxicities, recurrence, and complications. Wearable devices can provide critical information to achieve this goal; however, inferences are significantly influenced by device wear adherence. ObjectiveThis study aimed to assess the feasibility of using wearable devices to monitor short- and long-term PA in adolescent and young adult (AYA) patients with sarcoma during and after chemotherapy in a free-living environment and evaluate the ability to accurately capture changes in PA over 3 years. MethodsA total of 63 AYA patients with sarcoma were provided with a Fitbit Charge 3 to track daily steps, sedentary time, and heart rate for up to 3 years. ResultsOn average, during the first 30 days of follow-up, 57.1% (36/63) of patients wore their device at least 10 hours per day, and only 23.8% (15/63) of patients wore their devices thereafter. Patients spent a mean of 80% (SD 11%) of their day in a sedentary state. Despite low adherence, daily step count trends increased over time. ConclusionsThis study highlights the adherence challenges met with longitudinal PA monitoring in AYA patients with sarcoma. Wearer discomfort, lost devices, and lack of data uploading compliance contributed to data missingness and attrition. Caution is warranted when relying on wearable activity trackers to inform program decisions, accurately assess PA outcomes, and monitor program adherence longitudinally without consideration of wearer bias. Alternative methods that would be more broadly accepted by AYA patients for effective long-term monitoring should be considered.

BACKGROUND:Adolescents and young adults (AYAs) with sarcomas often receive high-dose doxorubicin (Dox), but data on early cardiotoxicity in this population are limited. OBJECTIVES:To prospectively evaluate early echocardiographic changes in AYAs with sarcoma treated with high-dose Dox. METHODS:AYAs (15-39 years) with sarcoma treated at a tertiary cancer centre (2018-22) were prospectively enroled. Echocardiograms were performed at baseline, 1 and 2 years after cancer therapy initiation and interpreted by a single cardiologist. The primary endpoint was a >10% absolute reduction in left ventricular ejection fraction (LVEF), an absolute LVEF <50%, or >10% decrease in LV wall thickness/dimension (LVWT/D) ratio from baseline. Secondary endpoints included longitudinal changes in cardiac structure, chamber volumes, systolic and diastolic function, and strain. RESULTS:Of 70 patients, 56 completed at least two of three study echocardiograms (median age 22.6 [IQR, 17.6-30.5] years; 41% female, 84% white). Median cumulative Dox dose was 450 (IQR, 370-450) mg/m2; 75% received dexrazoxane. The primary endpoint was met by 44.4% at 1 year and 27.5% at 2 years, driven primarily by LVWT/D ratio decline (37% at 1 year, 25% at 2 years), while significant LVEF decline was observed in 11.1% and 2.5%, respectively. Significant absolute changes at 1 year included LVEF (-2.73 ± 4.3%, P < .001), global longitudinal strain magnitude (-1.37 ± 2.56%, P = .002), septal e' (-1.75 ± 2.48 cm/s, P < .001), and lateral e' (-2.78 ± 3.44 cm/s, P < .001), persisting at 2 years. One patient (1.8%) developed ventricular fibrillation and heart failure with reduced ejection fraction, with LVEF recovery within 1 year. CONCLUSIONS:Over one-third of AYAs with sarcoma met the primary endpoint at 1 year, with half of these abnormalities persisting at 2 years, primarily driven by LVWT/D ratio reductions. Subclinical changes in strain and diastolic function were observed, reflecting the broad cardiac impact of high-dose Dox in this population.

PURPOSE:Skeletal muscle (SM) loss occurs during early anthracycline treatment in adolescent and young adult (AYA) cancer patients. Identifying those at greatest risk is critical for prevention. This study aimed to determine if genetic variants previously associated with SM loss in the general population are also associated with SM loss in AYA cancer patients receiving anthracycline chemotherapy. METHODS:SM change was quantified via computed tomography for 138 AYA cancer patients. The genome-wide association studies (GWAS) catalog was queried to identify candidate variants associated with SM index (SMI) or sarcopenia. Of the 18 GWAS-implicated variants, genotyping data were available in the study population for nine. Multivariable logistic regression was performed for each variant and risk of SM loss at the end of treatment and 1-year follow-up with adjustment for anthracycline dose, radiation exposure, diagnosis, sex, age, and follow-up time. RESULTS:The T allele of rs97384 (chr11:61624181) located in the fatty acid desaturase 2 (FADS2) gene was associated with risk of SM loss with a significant association for SM density (SMD) at follow-up (odds ratio: 2.37, 95% confidence interval: 1.27-4.45, p = 0.007). This variant was also borderline significant (p < 0.10) for SMD at baseline and SMI at follow-up. Integration of other variants within the FADS2 region identified several loci with more significant associations with SM loss in our patient population than that conferred by rs97384. CONCLUSION:Genetic variants previously associated with SM loss in the general population were significantly associated with SMD reduction post-anthracycline treatment in AYAs. Thus, providing the possibility of SM loss risk assessment in this high-risk patient population.

BackgroundNew therapies are urgently needed for patients with osteosarcoma (OS). STAT3 and CD47 are potential therapeutic target in OS. Here we investigated the therapeutic activity of the orally bioavailable STAT3 inhibitor, WP1066, and anti-CD47 antibody using OS mouse models.MethodsCytotoxic effect of WP1066 against OS cell lines and its immunomodulatory effects were evaluated in vitro. Experimental metastasis and orthotopic syngeneic mouse models were used to investigate the therapeutic efficacy of WP1066 and anti-CD47 antibody. Further flow cytometric analysis was performed.ResultsSTAT3 was constitutively activated in multiple human and mouse OS cell lines. WP1066 suppressed STAT3 activation and induced apoptosis. WP1066 reduced the viability and proliferation of MDSCs and increased the expression level of MHC-II, and CD80 in macrophages. We demonstrated that WP1066 monotherapy prolonged the survival of mice with OS lung metastasis using an experimental metastasis and an orthotopic model. The therapeutic effect was significantly increased when WP1066 was combined with anti-CD47. This was associated with increased frequency of activated CD8+ T cells, NK cells and macrophages in the lungs and LDLNs.ConclusionOur preclinical studies support further investigation of targeting STAT3 and CD47 as novel immunotherapeutic approach against OS lung metastasis.

Background Osteosarcoma (OS) lung metastases remain a significant therapeutic challenge. Innate immune activation is a promising therapeutic approach. Innate immune agonists can modulate the tumor immune microenvironment and improve therapeutic response.Methods Using an experimental syngeneic OS lung metastasis BALB/c mouse model with K7M3-luc OS cells, we evaluated the antitumor effects of yeast-derived particulate β-glucan in prevention and therapeutic settings. We then assessed whether the CD40 agonist (CD40a) in combination with β-glucan increased therapeutic response in two different immune-competent mouse models of OS lung tumor burden.Results In the pretreatment settings, mice treated with β-glucan prior to OS cell infusion developed significantly fewer lung tumor burdens and had increased survival. Pretreatment with β-glucan prevented tumor cell seeding in the lungs. In tumor-bearing mice, β-glucan treatment significantly suppressed tumor growth and prolonged overall survival. β-glucan treatment increased activated pro-inflammatory M1-like macrophages and natural killer (NK) cells secreting interferon-γ and granzyme B in the lungs. Depletion studies showed that the antitumor effect of β-glucan was dependent on macrophages and NK cells. Additionally, β-glucan treatment also induced myelopoiesis in the bone marrow. The therapeutic benefit of β-glucan was further augmented when combined with CD40a. Combination therapy significantly increased the infiltration of activated macrophages, including tumor necrosis factor-α secreting macrophages, and NK cells into the lungs compared with monotherapy. Bulk RNA sequencing of lung tissue revealed that the combination treatment group exhibited enhanced activation of antitumor innate immune pathways.Conclusions Collectively, our findings demonstrate the antitumor activity of β-glucan against OS lung tumor burden, that combining β-glucan and CD40a increases therapeutic activity, and that this activity is mediated by activation of innate immunity (macrophages and NK cells).

Background: We generated a CD103+DC vaccine using K7M3 OS cell lysates (cDCV) and investigated its ability to induce regression of primary tumors, established lung metastases, and a systemic immune response. Methods: A bilateral tumor model was used to assess cDCV therapy efficacy and systemic immunity induction. K7M3 cells were injected into mice bilaterally. Right-sided tumors received PBS (control) or cDCV. Left-sided tumors were untreated. Tumor growth was compared between the vaccine-treated and untreated tumor on the contralateral side and compared to the control group. The immune cell profiles of the tumors, and tumor-draining lymph nodes (TdLNs) and spleen were evaluated. To determine the efficacy of systemic cDCV therapy against established lung metastases, K7M3 cells were injected intratibially. Leg amputation was performed 5 weeks later. Mice were treated intravenously with PBS or cDCV and euthanized 6 weeks later. Lungs, TdLNs and spleen were collected. The number and size of the lung nodules were quantified. The immune cell profile of tumor, and lymph nodes and spleen were also evaluated. Using this same model, we evaluated the effect of cDCV + anti-CTLA-4. Results: cDCV therapy inhibited the treated and untreated tumors and increased the number of T-cells in these tumors and the lymph nodes compared to control-treated mice. Systemic cDCV therapy administered following amputation decreased the size and number of lung metastases, and increased T-cell numbers in the tumor and lymph nodes. Combining anti-CTLA-4 with cDCV therapy increased cDCV efficacy against lung metastases. Conclusions: Intratumor cDCV generated a systemic immune response inhibiting the growth of both the treated and untreated tumors, with increased T-cells in the tumor and lymph nodes. Systemic cDCV was effective against established lung metastases. Efficacy was increased by anti-CTLA4. cDCVs may provide a novel therapeutic approach for relapsed/metastatic OS patients.

Supplementary Figure 1: Table showing tumor spectrum in IL27RA-/- p53R172H/+ mice.

PDF file - 660KB, Detection of CD31, an endothelial cell marker on CTC.

Supplementary file: Previous therapies, Overall survival S1 : Prior therapies of patients with osteosarcoma enrolled on the Radium 223 trial. Supplementary Table S2: Adverse events in patients with osteosarcoma enrolled on the Radium 223 trial. Supplementary Figure 1: Overall survival of patients with osteosarcoma enrolled on the Radium 223 trial. Supplementary Figure 2: Correlation of % change in RECIST with relative change in LDH. Table 3: Table 1. Ra-223 dichloride Dose Escalation scheme (N=3/cohort)

Abstract Background Cure rates for osteosarcoma (OS) have not improved in >30 years and no new effectivetherapies have been identified for metastatic disease. Natural killer (NK) cells have become an attractive tool for cancer immunotherapy. Efficay is improved by direct tumor targeting introducing a specific chimeric antigen receptor (CAR). Emerging knowledge suggests CD70 to be a viable candidate as expression is higher in lung metastases and it has been correlated with tumor escape from immune surveillance. Objective To assess whether using CD70 CAR-NK cells we can enhance trafficking, homing and proliferation of NK cells and therefore therapeutic efficacy against OS. Methods We analyzed the cBioportal database to verify CD70 expression in OS. Surface expression of CD70 on human OS cell lines and normal osteoblasts was determined by flow cytometry. CD70 CAR constructs were sequenced, verified and transduced into NK cells. CD70 CAR NK and control NK cells cytolytic activity against OS cells was evaluated by IncuCyte. In vitro cytokine release was measured upon CD70 CAR NK/NK cells exposure to OS cells (IsoPlexis). Results Database analysis confirmed OS CD70 gene amplification. Flow cytometry showed variable expression of CD70 on OS cells and no expression on human osteoblasts. There was an increase in CD70 CAR NK percent lysis against OS cells at the highest effector:target ratios compared to control NK cells. We found a predominant release in the chemoattractive/stimulatory cytokines upon OS cells exposure to CD70 CAR NK cells. Conclusion CD70 has immunotherapy potential against OS. CD70 CAR NK cells have increased cytolytic activity against OS cells in vitro. Cytolytic activity may be influenced by the release of specific cytokines.

Abstract Background Early skeletal muscle loss has been observed in adolescent and young adult (AYA) sarcoma patients undergoing treatment. Identification of individuals within the AYA populace that are at greatest risk of anthracycline‐induced skeletal muscle loss is unknown. Moreover, investigations which seek out underlying causes of skeletal muscle degradation during chemotherapy are critical for understanding, preventing, and reducing chronic health conditions associated with poor skeletal muscle status. Methods Computed tomography (CT) scans were used to investigate changes in skeletal muscle of 153 AYA sarcoma and Hodgkin lymphoma patients at thoracic vertebra 4 after anthracycline treatment. Images were examined at three time points during the first year of treatment. In parallel, we used translational juvenile mouse models to assess the impact of doxorubicin (DOX) in the soleus and gastrocnemius on muscle wasting. Results Significant reductions in total skeletal muscle index and density were seen after chemotherapy in AYA cancer patients (p < 0.01 & p = 0.04, respectively). The severity of skeletal muscle loss varied by subgroup (i.e., cancer type, sex, and treatment). Murine models demonstrated a reduction in skeletal muscle fiber cross‐sectional area, increased apoptosis and collagen volume for both the soleus and gastrocnemius after DOX treatment (all p < 0.05). After DOX, hindlimb skeletal muscle blood flow was significantly reduced (p < 0.01). Conclusion Significant skeletal muscle loss is experienced early during treatment in AYA cancer patients. Reductions in skeletal muscle blood flow may be a key contributing factor to anthracycline doxorubicin induced skeletal muscle loss.

Supplementary Figure 3: Recombinant IL27 induces proliferation and invasion but not migration in-vitro in an osteosarcoma cell line.

Abstract Purpose: To define a set of biomarkers that can be used to identify patients at high risk of developing late doxorubicin (DOX)-induced cardiac morbidity with the goal of focused monitoring and early interventions. Experimental Design: Mice received phosphate buffered saline or DOX 2.5 mg/kg 2x/week for 2 weeks. Blood samples were obtained before and after therapy for quantification of miRNAs (6 and 24 hours), cytokines (24 hours), and troponin (24 hours, 4 and 6 weeks). Cardiac function was evaluated using echocardiography before and 24 hours after therapy. To assess the effectiveness of exercise intervention in preventing DOX-induced cardiotoxicity blood samples were collected from mice treated with DOX or DOX + exercise. Plasma samples from 13 DOX-treated patients with sarcoma were also evaluated before and 24 hours after therapy. Results: Elevations in plasma miRNA-1, miRNA-499 and IL1α, IL1β, and IL6 were seen in DOX-treated mice with decreased ejection fraction and fractional shortening 24 hours after DOX therapy. Troponin levels were not elevated until 4 weeks after therapy. In mice treated with exercise during DOX, there was no elevation in these biomarkers and no change in cardiac function. Elevations in these biomarkers were seen in 12 of 13 patients with sarcoma treated with DOX. Conclusions: These findings define a potential set of biomarkers to identify and predict patients at risk for developing acute and late cardiovascular diseases with the goal of focused monitoring and early intervention. Further studies are needed to confirm the predictive value of these biomarkers in late cardiotoxicity.