Multicellular tumor-stromal interactions recapitulate aspects of therapeutic response and human oncogenic signaling in a 3D disease model for H3K27M-altered DIPG.

It has become evident from decades of clinical trials that multimodal therapeutic approaches with focus on cell intrinsic and microenvironmental cues are needed to improve understanding and treat the rare, inoperable, and ultimately fatal diffuse intrinsic pontine glioma (DIPG), now categorized as a diffuse midline glioma. In this study we report the development and characterization of an in vitro system utilizing 3D Tumor Tissue Analogs (TTA), designed to replicate the intricate DIPG microenvironment. The innate ability of fluorescently labeled human brain endothelial cells, microglia, and patient-derived DIPG cell lines to self-assemble has been exploited to generate multicellular 3D TTAs that mimic tissue-like microstructures, enabling an in- depth exploration of the spatio-temporal dynamics between neoplastic and stromal cells.

Quantitative noninvasive measurement of cerebrospinal fluid flow in shunted hydrocephalus.

Objective: Standard MRI protocols lack a quantitative sequence that can be used to evaluate shunt-treated patients with a history of hydrocephalus. The objective of this study was to investigate the use of phase-contrast MRI (PC-MRI), a quantitative MR sequence, to measure CSF flow through the shunt and demonstrate PC-MRI as a useful adjunct in the clinical monitoring of shunt-treated patients.

Methods: The rapid (96 seconds) PC-MRI sequence was calibrated using a flow phantom with known flow rates ranging from 0 to 24 mL/hr.

Ex Vivo Drug Screening Assay with Artificial Membranes: Characterizing Cholesterol Desorbing Competencies of Beta-Cyclodextrins.

Despite advancements in contemporary therapies, cardiovascular disease from atherosclerosis remains a leading cause of mortality worldwide. Supported lipid bilayers (SLBs) are membrane interfaces that can be constructed with varying lipid compositions. Herein, we use a solvent-assisted lipid bilayer (SALB) construction method to build SLB membranes with varying cholesterol compositions to create a lipid-sterol interface atop a piezoelectric sensor.

Development of an ultrafast brain MR neuronavigation protocol for ventricular shunt placement.

Objective: Advancements in MRI technology have provided improved ways to acquire imaging data and to more seamlessly incorporate MRI into modern pediatric surgical practice. One such situation is image-guided navigation for pediatric neurosurgical procedures, including intracranial catheter placement. Image-guided surgery (IGS) requires acquisition of CT or MR images, but the former carries the risk of ionizing radiation and the latter is associated with long scan times and often requires pediatric patients to be sedated.

Tumor Tissue Analogs for the Assessment of Radioresistance in Cancer Stem Cells.

Over the years, radiotherapy-related research has been based on local tumor control as an experimental endpoint, yielding a wealth of data demonstrating the importance of cancer stem cells in tumor reoccurrence after radiotherapy. Literature is replete with experimental and clinical evidence that the cancer stem cell population in a tumor affects its radiocurability. An important consideration for radiotherapy is the microenvironmental stimuli in the CSC niche that results from factors such as hypoxia, extracellular matrix (ECM) elements and their intercellular interaction with non-stem cells and other cell types that prevail in the tumor milieu.

An ensemble predictive modeling framework for breast cancer classification.

Molecular changes often precede clinical presentation of diseases and can be useful surrogates with potential to assist in informed clinical decision making. Recent studies have demonstrated the usefulness of modeling approaches such as classification that can predict the clinical outcomes from molecular expression profiles. While useful, a majority of these approaches implicitly use all molecular markers as features in the classification process often resulting in sparse high-dimensional projection of the samples often comparable to that of the sample size.

Toxicity evaluation of magnetic hyperthermia induced by remote actuation of magnetic nanoparticles in 3D micrometastasic tumor tissue analogs for triple negative breast cancer.

Magnetic hyperthermia as a treatment modality is acquiring increased recognition for loco-regional therapy of primary and metastatic lung malignancies by pulmonary delivery of magnetic nanoparticles (MNP). The unique characteristic of magnetic nanoparticles to induce localized hyperthermia in the presence of an alternating magnetic field (AMF) allows for preferential killing of cells at the tumor site. In this study we demonstrate the effect of hyperthermia induced by low and high dose of MNP under the influence of an AMF using 3D tumor tissue analogs (TTA) representing the micrometastatic, perfusion independent stage of triple negative breast cancer (TNBC) that infiltrates the lungs.

An approach for deciphering patient-specific variations with application to breast cancer molecular expression profiles.

Several studies have successfully used molecular expression profiling in conjunction with classification techniques for discerning distinct disease groups. However, a majority of these studies do not provide sufficient insights into potential patient-specific variations within the disease groups. Such variations are ubiquitous and manifests across multiple scales with varying resolution.

Radiation-enhanced therapeutic targeting of galectin-1 enriched malignant stroma in triple negative breast cancer.

Currently there are no FDA approved targeted therapies for Triple Negative Breast Cancer (TNBC). Ongoing clinical trials for TNBC have focused primarily on targeting the epithelial cancer cells. However, targeted delivery of cytotoxic payloads to the non-transformed tumor associated-endothelium can prove to be an alternate approach that is currently unexplored.

Investigating the Radioresistant Properties of Lung Cancer Stem Cells in the Context of the Tumor Microenvironment.

Lung cancer is the most common cause of cancer-related deaths worldwide and non-small cell lung cancer (NSCLC) accounts for ~85% of all lung cancer. While recent research has shown that cancer stem cells (CSC) exhibit radioresistant and chemoresistant properties, current cancer therapy targets the bulk of the tumor burden without accounting for the CSC and the contribution of the tumor microenvironment. CSC interaction with the stroma enhances NSCLC survival, thus limiting the efficacy of treatment.

An in vitro assessment of liposomal topotecan simulating metronomic chemotherapy in combination with radiation in tumor-endothelial spheroids.

Low dose metronomic chemotherapy (LDMC) refers to prolonged administration of low dose chemotherapy designed to minimize toxicity and target the tumor endothelium, causing tumor growth inhibition. Topotecan (TPT) when administered at its maximum tolerated dose (MTD) is often associated with systemic hematological toxicities. Liposomal encapsulation of TPT enhances efficacy by shielding it from systemic clearance, allowing greater uptake and extended tissue exposure in tumors.

3D tumor tissue analogs and their orthotopic implants for understanding tumor-targeting of microenvironment-responsive nanosized chemotherapy and radiation.

Unlabelled: An appropriate representation of the tumor microenvironment in tumor models can have a pronounced impact on directing combinatorial treatment strategies and cancer nanotherapeutics. The present study develops a novel 3D co-culture spheroid model (3D TNBC) incorporating tumor cells, endothelial cells and fibroblasts as color-coded murine tumor tissue analogs (TTA) to better represent the tumor milieu of triple negative breast cancer in vitro. Implantation of TTA orthotopically in nude mice, resulted in enhanced growth and aggressive metastasis to ectopic sites.

Insights into accelerated liposomal release of topotecan in plasma monitored by a non-invasive fluorescence spectroscopic method.

A non-invasive fluorescence method was developed to monitor liposomal release kinetics of the anticancer agent topotecan (TPT) in physiological fluids and subsequently used to explore the cause of accelerated release in plasma. Analyses of fluorescence excitation spectra confirmed that unencapsulated TPT exhibits a red shift in its spectrum as pH is increased. This property was used to monitor TPT release from actively loaded liposomal formulations having a low intravesicular pH.

Tumor microenvironment and nanotherapeutics.

Recent studies delineate a predominant role for the tumor microenvironment in tumor growth and progression. Improved knowledge of cancer biology and investigation of the complex functional interrelation between the cellular and noncellular compartments of the tumor microenvironment have provided an ideal platform for the evolution of novel cancer nanotherapies. In addition, multifunctional "smart" nanoparticles carrying imaging agents and delivering multiple drugs targeted preferentially to the tumor/tumor microenvironment will lead to early diagnosis and better treatment for patients with cancer.

Radiation-induced galectin-1 by endothelial cells: a promising molecular target for preferential drug delivery to the tumor vasculature.

The present study reports on a new strategy for selective, radiation therapy-amplified drug delivery using an antiangiogenic 33-a.a., tumor vasculature-targeting ligand, anginex, to improve the therapeutic ratio for strategies developed against solid tumors.

Vascular disrupting agent arsenic trioxide enhances thermoradiotherapy of solid tumors.

Our previous studies demonstrated arsenic trioxide- (ATO-) induced selective tumor vascular disruption and augmentation of thermal or radiotherapy effect against solid tumors. These results suggested that a trimodality approach of radiation, ATO, and local hyperthermia may have potent therapeutic efficacy against solid tumors. Here, we report the antitumor effect of hypofractionated radiation followed by ATO administration and local 42.

Tumor-Endothelial Cell Three-dimensional Spheroids: New Aspects to Enhance Radiation and Drug Therapeutics.

Classic cancer research for several decades has focused on understanding the biology of tumor cells in vitro. However, extending these findings to in vivo settings has been impeded owing to limited insights on the impact of microenvironment on tumor cells. We hypothesized that tumor cell biology and treatment response would be more informative when done in the presence of stromal components, like endothelial cells, which exist in the tumor microenvironment.

Inferring functional relationships and causal network structure from gene expression profiles.

Inferring functional relationships and network structure from the observed gene expression profiles can provide a novel insight into the working of the genes as a system or network as opposed to independent entities. Such networks may also represent possible causal relationships between a given set of genes, hence can prove to be a convenient abstraction of the underlying signaling mechanism. The discovery of functional relationships from the observed gene expression profiles does not rely on prior literature, hence useful in identifying undocumented relationships between a given set of genes.

Granger causality analysis of human cell-cycle gene expression profiles.

Granger causality (GC) tests are ideally suited to investigate time series data generated by bivariate vector autoregressive (VAR) processes. Recent studies have applied GC analysis and its extensions for modeling functional relationships and network structure from temporal gene expression profiles. The present study investigates GC analysis of human cell-cycle gene expression profiles that can be modeled as a first-order bivariate VAR.

Cyclin-dependent kinase 1-mediated Bcl-xL/Bcl-2 phosphorylation acts as a functional link coupling mitotic arrest and apoptosis.

Despite detailed knowledge of the components of the spindle assembly checkpoint, a molecular explanation of how cells die after prolonged spindle checkpoint activation, and thus how microtubule inhibitors and other antimitotic drugs ultimately elicit their lethal effects, has yet to emerge. Mitotically arrested cells typically display extensive phosphorylation of two key antiapoptotic proteins, Bcl-x(L) and Bcl-2, and evidence suggests that phosphorylation disables their antiapoptotic activity. However, the responsible kinase has remained elusive.

Synthesis and anticancer activity of sclerophytin-inspired hydroisobenzofurans.

Three structurally related sets of hydroisobenzofuran analogs of sclerophytin A were prepared in three or four steps from (S)-(+)-carvone via an aldol-cycloaldol sequence. The most potent members of each set of analogs exhibited IC(50)'s of 1-3 microM in growth inhibitory assays against KB3 cells. The NCI 60-cell line 5-dose assay for analog 6h revealed a GI(50)=0.

Regulation of Bax by c-Jun NH2-terminal kinase and Bcl-xL in vinblastine-induced apoptosis.

Microtubule inhibitors, such as vinblastine, are widely used in cancer chemotherapy. Vinblastine exerts its antitumor effect by inducing apoptosis. In KB-3 cells, we have shown previously that vinblastine activates c-Jun NH(2)-terminal protein kinase (JNK) and causes Bax mitochondrial translocation and activation.

Identification of the major phosphorylation site in Bcl-xL induced by microtubule inhibitors and analysis of its functional significance.

Vinblastine and other microtubule inhibitors used as antimitotic cancer drugs characteristically promote the phosphorylation of the key anti-apoptotic protein, Bcl-xL. However, putative sites of phosphorylation have been inferred based on potential recognition by JNK, and no direct biochemical analysis has been performed. In this study we used protein purification and mass spectrometry to identify Ser-62 as a single major site in vivo.

Key role for Bak activation and Bak-Bax interaction in the apoptotic response to vinblastine.

Microtubule inhibitors such as vinblastine cause mitotic arrest and subsequent apoptosis through the intrinsic mitochondrial pathway. However, although Bcl-2 family proteins have been implicated as distal mediators, their precise role is largely unknown. In this study, we investigated the role of Bak in vinblastine-induced apoptosis.