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This Week in Cancer Discovery: May 30, 2012

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In Cancer Discovery, researchers in the US and Australia report that pre-existing MEK1 exon 3 mutations in V600E/KBRAF melanomas don't confer resistance to BRAF inhibitors. The team sequenced MEK1/2 exon 3 in 31 melanomas at disease diagnosis and at progression, and found that five of them carried concurrent somatic BRAF/MEK1 activating mutations. Three of those five patients showed objective responses to BRAF inhibitors, consistent with the overall response rate to these drugs. "MEK1-mutant expression in V600E/KBRAF melanoma cell lines resulted in no significant alterations in p-ERK1/2 levels or growth-inhibitory sensitivities to BRAFi, MEK1/2 inhibitor, or their combination," the authors write. "Thus, activating MEK1 exon 3 mutations identified herein and concurrent with V600E/KBRAF do not cause BRAF [inhibitor] resistance in melanoma."

Also in Cancer Discovery, researchers at Harvard Medical School and Dana-Farber Cancer Institute present their functional characterization of an isoform-selective inhibitor of PI3K-p110β. The team used a panel of PI3K isoform-specific cellular assays to screen compounds that act against kinases in the PI3K superfamily. They identified a selective p110β inhibitor called KIN-193, which they say is "efficacious specifically in blocking AKT signaling and tumor growth that are dependent on p110β activation or PTEN loss." When the drug was profiled across a panel of 422 human tumor cell lines, the team found that the cancer cells' PTEN mutation status strongly correlated with their response to KIN-193. "Together, our data provide the first pharmacologic evidence that PTEN-deficient tumors are dependent on p110β in animals and suggest that KIN-193 can be pursued as a drug to treat tumors that are dependent on p110β while sparing other PI3K isoforms," they add.

The Scan

Call to Look Again

More than a dozen researchers penned a letter in Science saying a previous investigation into the origin of SARS-CoV-2 did not give theories equal consideration.

Not Always Trusted

In a new poll, slightly more than half of US adults have a great deal or quite a lot of trust in the Centers for Disease Control and Prevention, the Hill reports.

Identified Decades Later

A genetic genealogy approach has identified "Christy Crystal Creek," the New York Times reports.

Science Papers Report on Splicing Enhancer, Point of Care Test for Sexual Transmitted Disease

In Science this week: a novel RNA structural element that acts as a splicing enhancer, and more.