The complete removal of cancerous tissue is a central aim of surgical oncology, but is difficult to achieve in certain cases, especially when the removal of surrounding normal tissues must be minimized. Therefore, when post-operative pathology identifies residual tumor at the surgical margins, re-excision surgeries are often necessary. An intraoperative approach for tumor-margin assessment, insensitive to nonspecific sources of molecular probe accumulation and contrast, is presented employing kinetic-modeling analysis of dual-probe staining using surface-enhanced Raman scattering nanoparticles (SERS NPs). Human glioma (U251) and epidermoid (A431) tumors were implanted subcutaneously in six athymic mice. Fresh resected tissues were stained with an equimolar mixture of epidermal growth factor receptor (EGFR)-targeted and untargeted SERS NPs. The binding potential (BP; proportional to receptor concentration) of EGFR – a cell-surface receptor associated with cancer – was estimated from kinetic modeling of targeted and untargeted NP concentrations in response to serial rinsing. EGFR BPs in healthy, U251, and A431 tissues were 0.06 ± 0.14, 1.13 ± 0.40, and 2.23 ± 0.86, respectively, which agree with flow-cytometry measurements and published reports. The ability of this approach to quantify the BP of cell-surface biomarkers in fresh tissues opens up an accurate new approach to analyze tumor margins intraoperatively.

SUMMARY Accumulation of visceral adiposity is directly linked to the morbidity of obesity, while subcutaneous body fat is considered more benign. We have identified an unexpected role for B cell lymphoma 6 (BCL6), a critical regulator of immunity, in the developmental expansion of subcutaneous adipose tissue. In adipocyte-specific knockout mice (Bcl6AKO), we found that Bcl6 deletion results in strikingly increased inguinal, but not perigonadal, adipocyte size and tissue mass in addition to marked insulin sensitivity. Genome-wide RNA expression and DNA binding analyses revealed that BCL6 controls gene networks involved in cell growth and fatty acid biosynthesis. Using deuterium label incorporation and comprehensive adipokine and lipid profiling, we discovered that ablation of adipocyte Bcl6 enhances subcutaneous adipocyte lipogenesis, increases levels of adiponectin and fatty acid esters of hydroxy fatty acids (FAHFAs), and prevents steatosis. Thus, our studies identify BCL6 as a negative regulator of subcutaneous adipose tissue expansion and metabolic health.

BackgroundDoxorubicin and doxorubicin‐trastuzumab combination chemotherapy have been associated with cardiotoxicity that eventually leads to heart failure and may limit dose‐effective cancer treatment. Current diagnostic strategies rely on decreased ejection fraction (EF) to diagnose cardiotoxicity.PurposeThe aim of this study is to explore the potential of cardiac MR (CMR) imaging to identify imaging biomarkers in a mouse model of chemotherapy‐induced cardiotoxicity.MethodsA cumulative dose of 25 mg/kg doxorubicin was administered over three weeks using subcutaneous pellets (n = 9, Dox). Another group (n = 9) received same dose of Dox and a total of 10 mg/kg trastuzumab (DT). Mice were imaged at baseline, 5/6 weeks and 10 weeks post‐treatment on a 7T MRI system. The protocol included short‐axis cine MRI covering the left ventricle (LV) and mid‐ventricular short‐axis tissue phase mapping (TPM), pre‐ and post‐contrast T1 mapping, T2 mapping and Displacement Encoding with Stimulated Echoes (DENSE) strain encoded MRI. EF, peak myocardial velocities, native T1, T2, extracellular volume (ECV), and myocardial strain were quantified. N = 7 mice were sacrificed for histopathologic assessment of apoptosis at 5/6 weeks.ResultsGlobal peak systolic longitudinal velocity was reduced at 5/6 weeks in Dox (0.6 ± 0.3 vs 0.9 ± 0.3, p = 0.02). In the Dox group, native T1 was reduced at 5/6 weeks (1.3 ± 0.2 ms vs 1.6 ± 0.2 ms, p = 0.02), and relatively normalized at week 10 (1.4 ± 0.1 ms vs 1.6 ± 0.2 ms, p > 0.99). There was no change in EF and other MRI parameters and histopathologic results demonstrated minimal apoptosis in all mice (~1–2 apoptotic cell/high power field), suggesting early‐stage cardiotoxicity.ConclusionsIn a mouse model of chemotherapy‐induced cardiotoxicity using doxorubicin and trastuzumab, advanced CMR shows promise in identifying treatment‐related decrease in myocardial velocity and native T1 prior to the onset of cardiomyocyte apoptosis and reduction of EF.

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Immunofluorescence staining is a robust way to visualize the distribution of targeted biomolecules invasively in in fixed tissues and tissue culture. Despite the fact that these methods has been a well-established method in fixed tissue imaging for over 70 years, quantification of receptor concentration still simply assumes that the signal from the targeted fluorescent marker after incubation and sufficient rinsing is directly proportional to the concentration of targeted biomolecules, thus neglecting the experimental inconsistencies in incubation and rinsing procedures and assuming no, nonspecific binding of the fluorescent markers. This work presents the first imaging approach capable of quantifying the concentration of cell surface receptor on cancer cells grown in vitro based on compartment modeling in a nondestructive way. The approach utilizes a dual-tracer protocol where any non-specific retention or variability in incubation and rinsing of a receptor-targeted imaging agent is corrected by simultaneously imaging the retention of a chemically similar, "untargeted" imaging agent. Various different compartment models were used to analyze the data in order to find the optimal procedure for extracting estimates of epidermal growth factor receptor (EGFR) concentration (a receptor overexpressed in many cancers and a key target for emerging molecular therapies) in tissue cultures with varying concentrations of human glioma cells (U251). Preliminary results demonstrated a need to model nonspecific binding of both the targeted and untargeted imaging agents used. The approach could be used to carry out the first repeated measures of cell surface receptor dynamics during 3D tumor mass development, in addition to the receptor response to therapies.