Novel somatic mutations in heterotrimeric G proteins in melanoma.

Heterotrimeric guanine nucleotide-binding proteins (G proteins) mediate signals between G-protein coupled receptors and their downstream pathways, and have been shown to be mutated in cancer. In particular, GNAQ was found to be frequently mutated in blue nevi of the skin and uveal melanoma, acting as an oncogene in its mutated form. To further examine the role of heterotrimeric G proteins in malignant melanoma, we performed a comprehensive mutational analysis of the 35 genes in the heterotrimeric G protein gene family in a panel of 80 melanoma samples.

The pervasive presence of fluctuating oxygenation in tumors.

Tumor hypoxia is a persistent obstacle for traditional therapies in solid tumors. Strategies for mitigating the effects of hypoxic tumor cells have been developed under the assumption that chronically hypoxic tumor cells were the central cause of treatment resistance. In this study, we show that instabilities in tumor oxygenation are a prevalent characteristic of three tumor lines and previous characterization of tumor hypoxia as being primarily diffusion-limited does not accurately portray the tumor microenvironment.

Requirements for T lymphocyte migration in explanted lymph nodes.

Although the requirements for T lymphocyte homing to lymph nodes (LNs) are well studied, much less is known about the requirements for T lymphocyte locomotion within LNs. Imaging of murine T lymphocyte migration in explanted LNs using two-photon laser-scanning fluorescence microscopy provides an opportunity to systematically study these requirements. We have developed a closed system for imaging an intact LN with controlled temperature, oxygenation, and perfusion rate.

Targeting the molecular effects of a hypoxic tumor microenvironment.

Tumor hypoxia is a serious and enduring problem for traditional solid tumor therapies. Many scientists continue to explore methods to improve or exploit tumor oxygenation; more recently, scientists have also focused on altering the molecular effects of hypoxia. These cellular responses to hypoxia and the resulting physiological effects, with a focus on angiogenesis, invasion/metastases, apoptosis, and metabolism, are examined.

Effects of fluctuating oxygenation on tirapazamine efficacy: Theoretical predictions.

Purpose: To examine the effects of fluctuating oxygen levels on the hypoxic cytotoxin tirapazamine (TPZ) using theoretical predictions.

Methods And Materials: Tirapazamine's pharmacokinetic and pharmacodynamic oxygen dependence has previously been characterized in vitro. Here, a one-dimensional theoretical model was used to examine the effects of fluctuating hypoxia on metabolized TPZ concentration, assuming sinusoidally fluctuating oxygen levels.