The Tumor-Immune Microenvironment and Response to Radiation Therapy

Chemotherapy and radiation therapy (RT) are standard therapeutic modalities for patients with cancer, including breast cancer. Historic studies examining tissue and cellular responses to RT have predominantly focused on damage caused to proliferating malignant cells leading to their death. However, there is increasing evidence that RT also leads to significant alterations in the tumor microenvironment, particularly with respect to effects on immune cells infiltrating tumors. This review focuses on tumor-associated immune cell responses following RT and discusses how immune responses may be modified to enhance durability and efficacy of RT

The Anti-Cancer Multikinase Inhibitor Sorafenib Impairs Cardiac Contractility by Reducing Phospholamban Phosphorylation and Sarcoplasmic Calcium Transients

Abstract Tyrosine-kinase inhibitors (TKIs) have revolutionized cancer therapy in recent years. Although more targeted than conventional chemotherapy, TKIs exhibit substantial cardiotoxicity, often manifesting as hypertension or heart failure. Here, we assessed myocyte intrinsic cardiotoxic effects of the TKI sorafenib and investigated underlying alterations of myocyte calcium homeostasis. We found that sorafenib reversibly decreased developed force in auxotonically contracting human myocardia (3 µM: −25 ± 4%, 10 µM: −29 ± 7%, 30 µM: −43 ± 12%, p < 0.01), reduced peak cytosolic calcium concentrations in isolated cardiomyocytes (10 µM: 52 ± 8.1% of baseline, p < 0.001), and slowed cytosolic calcium removal kinetics (RT50, RT10, Tau, p < 0.05). Beta-adrenergic stimulation induced augmentation of calcium transient (CaT) amplitude was attenuated in sorafenib-treated cells (2.7 ± 0.3-fold vs. 3.6 ± 0.2-fold in controls, p < 0.001). Sarcoplasmic reticulum (SR) calcium content was reduced to 67 ± 4% (p < 0.01), and SR calcium re-uptake slowed (p < 0.05). Sorafenib significantly reduced serine 16 phosphorylation of phospholamban (PLN, p < 0.05), while PLN threonine 17 and CaMKII (T286) phosphorylation were not altered. Our data demonstrate that sorafenib acutely impairs cardiac contractility by reducing S16 PLN phosphorylation, leading to reduced SR calcium content, CaT amplitude, and slowed cytosolic calcium removal. These results indicate myocyte intrinsic cardiotoxicity irrespective of effects on the vasculature and chronic cardiac remodeling

Combine Phage Antibody Display Library Selection on Patient Tissue Specimens with Laser Capture Microdissection to Identify Novel Human Antibodies Targeting Clinically Relevant Tumor Antigens

A functional approach to generate tumor-targeting human monoclonal antibodies is through selection of phage antibody display libraries directly on tumor cells. Although technically convenient, the use of cancer cell lines for the selection has limitations as those cell lines often undergo genetic and epigenetic changes during prolonged in vitro culture and alter their cell surface antigen expression profile. The key is to develop a technology that allows selection of phage antibody display libraries on tumor cells in situ residing in their natural tissue microenvironment. Laser capture microdissection (LCM) permits the precise procurement of tumor cells from human cancer patient tissue sections. Here, we describe a LCM-based method for selecting phage antibodies against tumor cells in situ using both fresh frozen and paraffin-embedded tissues. To restrict the selection to antibodies that bind internalizing epitopes, the method utilizes a polyclonal phage population pre-enriched for internalizing phage antibodies. The ability to recognize tumor cells in situ residing in their natural tissue microenvironment and to deliver payload intracellularly makes these LCM-selected antibodies attractive candidates for the development of targeted cancer therapeutics