Preclinical development of a chimeric antigen receptor T cell therapy targeting FGFR4 in rhabdomyosarcoma.

Pediatric patients with relapsed or refractory rhabdomyosarcoma (RMS) have dismal cure rates, and effective therapy is urgently needed. The oncogenic receptor tyrosine kinase fibroblast growth factor receptor 4 (FGFR4) is highly expressed in RMS and lowly expressed in healthy tissues. Here, we describe a second-generation FGFR4-targeting chimeric antigen receptor (CAR), based on an anti-human FGFR4-specific murine monoclonal antibody 3A11, as an adoptive T cell treatment for RMS. The 3A11 CAR T cells induced robust cytokine production and cytotoxicity against RMS cell lines in vitro. In contrast, a panel of healthy human primary cells failed to activate 3A11 CAR T cells, confirming the selectivity of 3A11 CAR T cells against tumors with high FGFR4 expression. Finally, we demonstrate that 3A11 CAR T cells are persistent in vivo and can effectively eliminate RMS tumors in two metastatic and two orthotopic models. Therefore, our study credentials CAR T cell therapy targeting FGFR4 to treat patients with RMS.

Optimizing evaluation in pediatric and young adult patients with Marfan syndrome: Novel longitudinal metrics to track growth of aortic structures.

OBJECTIVE: Surveillance metrics in pediatric and young adult Marfan syndrome (pMFS) are challenging. We evaluated the utility of aortic root cross-sectional area/height index (CSA/Ht) on echocardiogram among pMFS patients as a risk stratification and surgical triage metric. METHODS: Genotype or phenotype positive pMFS patients aged 25 years or younger seen at our center from 2001 to 2020 were identified. Time-related transition to surgery was modeled using parametric methods. Predictive utility of CSA/Ht compared with aortic root diameter (ARd) and root Z score (ARz) were modeled using nonlinear multivariable parametric and nonparametric longitudinal regression models. RESULTS: Seventy-nine patients (43% female) presented at median age of 5.8 years (15th-85th percentile, 0.75-17 years) with median follow-up of 4.4 years (range, 0-18.5 years). Baseline echocardiography data were: CSA/Ht, 3.9 ± 1.4 cm2/m; ARd, 2.4 ± 0.89 cm; and ARz, 2.4 ± 1.7. CSA/Ht tracked ARd better compared with ARz (r = 0.91 vs 0.24). Eighteen patients underwent surgery. Surgical procedures included at least 2 components in 17 (aortic, mitral, tricuspid, aortic root, and arch procedures) and isolated mitral valve procedures in 1 patient. Time-related transition to surgery showed a prominent early phase to 1 year post presentation, followed by a slowly increasing late phase. CSA/Ht had a more linear correlation versus ARz during periods of rapid somatic growth in surgical patients. Surgical repair occurred at CSA/Ht between 5 and 7 cm2/m. CONCLUSIONS: CSA/Ht tracked ARd well over time. CSA/Ht between 5 and 7 cm2/m might be a promising metric for surgical triage in pMFS patients. CSA/Ht surgical threshold values in pMFS patients occurred at lower than current accepted "surgical" threshold values for CSA/Ht in adult Marfan syndrome patients.

Ability of the surgical Apgar score to predict acute kidney injury following radical cystectomy.

PURPOSE: Acute kidney injury (AKI) is a common complication after radical cystectomy (RC). Previous literature has shown that intraoperative hemodynamic instability measured via the surgical Apgar score is an independent predictor of major complications following RC. We sought to determine whether the surgical Apgar score is predictive of postoperative AKI. METHODS: We performed a retrospective review of RC patients at our institution from 2010 to 2017. Intraoperative hemodynamic instability was captured via the Apgar score based on the lowest intraoperative mean arterial blood pressure, lowest heart rate, and estimated blood loss. Patients were divided into 3 groups: high-risk (HR; Apgar ≤4), intermediate-risk (IR; Apgar score 5-6), and low-risk (LR; Apgar score ≥7). AKIs were graded according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria. High grade AKIs were defined as KDIGO grade 2 or 3. Categorical variables were assessed using the Pearson Chi-Square test, quantitative with the Kruskal-Wallis test, and multivariable logistic regression to identify predictors of AKI and high grade AKIs within 30 days of RC. RESULTS: Eight hundred and seventy-three patients were included with a median follow-up of 35 months. AKI within 30 days was observed in 28% of patients. Predictors of AKI within 30 days on adjusted analysis included IR (OR: 1.83, P = 0.002) and HR (OR: 3.53, P < 0.001) Apgar scores. IR (OR: 2.23, P = 0.007) and HR (OR: 4.87, P < 0.001) Apgar scores were also predictors of high-grade AKIs. CONCLUSION: Intraoperative hemodynamic instability measured via the Apgar score can be predictive of AKI, which can guide individualized fluid management in the postoperative period.

Hyperthermia-mediated changes in the tumor immune microenvironment using iron oxide nanoparticles.

Iron oxide nanoparticles (IONPs) have often been investigated for tumor hyperthermia. IONPs act as heating foci in the presence of an alternating magnetic field (AMF). It has been shown that hyperthermia can significantly alter the tumor immune microenvironment. Typically, mild hyperthermia invokes morphological changes within the tumor, which elicits a secretion of inflammatory cytokines and tumor neoantigens. Here, we focused on the direct effect of IONP-induced hyperthermia on the various tumor-resident immune cell subpopulations. We compared direct intratumoral injection to systemic administration of IONPs followed by application of an external AMF. We used the orthotopic 4T1 mouse model, which represents aggressive and metastatic breast cancer with a highly immunosuppressive microenvironment. A non-inflamed and 'cold' microenvironment inhibits peripheral effector lymphocytes from effectively trafficking into the tumor. Using intratumoral or systemic injection, IONP-induced hyperthermia achieved a significant reduction of all the immune cell subpopulations in the tumor. However, the systemic delivery approach achieved superior outcomes, resulting in substantial reductions in the populations of both innate and adaptive immune cells. Upon depletion of the existing dysfunctional tumor-resident immune cells, subsequent treatment with clinically approved immune checkpoint inhibitors encouraged the repopulation of the tumor with 'fresh' infiltrating innate and adaptive immune cells, resulting in a significant decrease of the tumor cell population.

PTPmu-targeted nanoparticles label invasive pediatric and adult glioblastoma.

Poor prognosis for glioblastoma (GBM) is a consequence of the aggressive and infiltrative nature of gliomas where individual cells migrate away from the main tumor to distant sites, making complete surgical resection and treatment difficult. In this manuscript, we characterize an invasive pediatric glioma model and determine if nanoparticles linked to a peptide recognizing the GBM tumor biomarker PTPmu can specifically target both the main tumor and invasive cancer cells in adult and pediatric glioma models. Using both iron and lipid-based nanoparticles, we demonstrate by magnetic resonance imaging, optical imaging, histology, and iron quantification that PTPmu-targeted nanoparticles effectively label adult gliomas. Using PTPmu-targeted nanoparticles in a newly characterized orthotopic pediatric SJ-GBM2 model, we demonstrate individual tumor cell labeling both within the solid tumor margins and at invasive and dispersive sites.

Effect of Dose and Selection of Two Different Ligands on the Deposition and Antitumor Efficacy of Targeted Nanoparticles in Brain Tumors.

Deposition of nanoparticles to tumors often can be enhanced by targeting receptors overexpressed in a tumor. However, a tumor may exhibit a finite number of a biomarker that is accessible and targetable by nanoparticles, limiting the available landing spots. To explore this, we selected two different biomarkers that effectively home nanoparticles in brain tumors. Specifically, we used either an αvß3 integrin-targeting peptide or a fibronectin-targeting peptide as a ligand on nanoparticles termed RGD-NP and CREKA-NP, respectively. In mouse models of glioblastoma multiforme, we systemically injected the nanoparticles loaded with a cytotoxic drug at different doses ranging from 2 to 8 mg/kg drug. The upper dose threshold of RGD-NP is ∼2 mg/kg. CREKA-NP reached its upper dose threshold at 5 mg/kg. For both targeted nanoparticle variants, higher dose did not ensure higher intratumoral drug levels, but it contributed to elevated off-target deposition and potentially greater toxicity. A cocktail combining RGD-NP and CREKA-NP was then administered at a dose corresponding to the upper dose threshold for each formulation resulting in a 3-fold higher intratumoral deposition than the individual formulations. The combination of the two different targeting schemes at the appropriate dose for each nanoparticle variant facilitated remarkable increase in intratumoral drug levels that was not achievable by a sole targeting nanoparticle alone.

Imaging breast cancer using a dual-ligand nanochain particle.

Nanoparticles often only exploit the upregulation of a receptor on cancer cells to enhance intratumoral deposition of therapeutic and imaging agents. However, a single targeting moiety assumes that a tumor is homogenous and static. Tumoral microenvironments are both heterogenous and dynamic, often displaying variable spatial and temporal expression of targetable receptors throughout disease progression. Here, we evaluated the in vivo performance of an iron oxide nanoparticle in terms of targeting and imaging of orthotropic mouse models of aggressive breast tumors. The nanoparticle, a multi-component nanochain, was comprised of 3-5 iron oxide nanoparticles chemically linked in a linear chain. The nanoparticle's surface was decorated with two types of ligands each targeting two different upregulated biomarkers on the tumor endothelium, P-selectin and fibronectin. The nanochain exhibited improved tumor deposition not only through vascular targeting but also through its elongated structure. A single-ligand nanochain exhibited a ~2.5-fold higher intratumoral deposition than a spherical nanoparticle variant. Furthermore, the dual-ligand nanochain exhibited higher consistency in generating detectable MR signals compared to a single-ligand nanochain. Using a 7T MRI, the dual-ligand nanochains exhibited highly detectable MR signal within 3h after injection in two different animal models of breast cancer.