Brief Communications in 2012

Doxorubicin, which induces tumor cell death through effects on topoisomerase-II, is a commonly used chemotherapeutic agent but has the substantial drawback of causing cardiotoxicity. Edward T.H.Yeh and his colleagues now show that doxorubicin-induced cardiotoxicity in mice is due to the deleterious effects of doxorubicin on topoisomerase-IIβ in cardiomyocytes, leading to alterations in gene expression, mitochondrial dysfunction and cell death.

A slight mechanical pressure applied to healthy skin results in blood vessel dilation, preserving blood flow. Defects in this vasodilatory response lead to an increased risk of pressure ulcers. Fromy et al. identify the neuronal mechanosensor that mediates this response in both rodents and humans: the ion channel Asic3.

Morphine loses its ability to fight pain after chronic use. Now, Howard Gutstein and his colleagues report that morphine induces release of PDGF, and blockade of PDGFR signaling can reestablish morphine analgesic efficacy in rats that have become tolerant.

Using high-coverage targeted next-generation sequencing, this report provides a catalog of genetic alterations in colorectal and lung cancers, identifying previously unknown alterations, such as JAK2 mutations and KIF5B-RET fusions, that may represent druggable targets.

The authors report a new type of genetic alteration in lung adenocarcinoma. Fusions of KIF5B with RET kinase are found in 1–2% of lung cancer patients, segregate from other known alterations and can potentially be targeted using RET kinase inhibitors.

Through an integrated screening system, the authors catalog ALK and ROS1 fusions in lung cancer and identify a new class of fusions involving KIF5B and RET that may represent new therapeutic targets in adenocarcinoma.

This report uncovers a direct link between cancer-driving inflammation and DNA methylation by showing that PGE₂ regulates the expression of DNA methylases, resulting in silencing of tumor-suppressor genes. The authors suggest that DNA methylation is an important component of the pathogenic effect of inflammatory signaling in colorectal cancer.

By modeling acquired resistance to the EGFR antibody cetuximab in metastatic colorectal cancer, the authors identify a new mutation in the ectodomain of the receptor. The mutation is present in patient tumors after cetuximab therapy, confirming that it represents a clinically-relevant mechanism for therapy resistance. Moreover, the mutation does not affect the response to other EGFR antibodies, suggesting that if independently confirmed it may be a useful indicator to tailor anti-EGFR therapy.