Autophagy supports PDGFRA-dependent brain tumor development by enhancing oncogenic signaling

Autophagy is a conserved cellular degradation process. While autophagy-related proteins were shown to influence the signaling and trafficking of some receptor tyrosine kinases, the relevance of this during cancer development is unclear. Here, we identify a role for autophagy in regulating platelet-derived growth factor receptor alpha (PDGFRA) signaling and levels. We find that PDGFRA can be targeted for autophagic degradation through the activity of the autophagy cargo receptor p62. As a result, short-term autophagy inhibition leads to elevated levels of PDGFRA but an unexpected defect in PDGFA-mediated signaling due to perturbed receptor trafficking. Defective PDGFRA signaling led to its reduced levels during prolonged autophagy inhibition, suggesting a mechanism of adaptation. Importantly, PDGFA-driven gliomagenesis in mice was disrupted when autophagy was inhibited in a manner dependent on Pten status, thus highlighting a genotype-specific role for autophagy during tumorigenesis. In summary, our data provide a mechanism by which cells require autophagy to drive tumor formation.

A Synergistic Anticancer FAK and HDAC Inhibitor Combination Discovered by a Novel Chemical-Genetic High-Content Phenotypic Screen

We mutated the focal adhesion kinase (FAK) catalytic domain to inhibit binding of the chaperone Cdc37 and ATP, mimicking the actions of a FAK kinase inhibitor. We reexpressed mutant and wild-type FAK in squamous cell carcinoma (SCC) cells from which endogenous FAK had been deleted, genetically fixing one axis of a FAK inhibitor combination high-content phenotypic screen to discover drugs that may synergize with FAK inhibitors. Histone deacetylase (HDAC) inhibitors represented the major class of compounds that potently induced multiparametric phenotypic changes when FAK was rendered kinase-defective or inhibited pharmacologically in SCC cells. Combined FAK and HDAC inhibitors arrest proliferation and induce apoptosis in a subset of cancer cell lines in vitro and efficiently inhibit their growth as tumors in vivo Mechanistically, HDAC inhibitors potentiate inhibitor-induced FAK inactivation and impair FAK-associated nuclear YAP in sensitive cancer cell lines. Here, we report the discovery of a new, clinically actionable, synergistic combination between FAK and HDAC inhibitors.

The need for early angiography in patients with penetrating renal injuries

BACKGROUND

Renal injuries occur in as many as 10% of penetrating abdominal wounds. Today, these wounds are often managed selectively, but there is little contemporary information on the natural history of kidney injuries after penetrating trauma. The purpose of this study was to examine the clinical outcomes of penetrating injuries to the kidney, and to determine if these patients may benefit from routine early angiography.

METHODS

All trauma patients admitted to three Level I Trauma Centers with penetrating renal injuries over a 10 year study period were retrospectively reviewed.

RESULTS

We identified 237 patients with a penetrating renal injury, of whom 39 died within the first 24 h and were excluded from analysis. Among the remaining 198 individuals, 130 (66%) underwent immediate exploratory laparotomy. Of the 68 subjects not undergoing immediate surgery, seven had early angiography. The remaining 61 patients (31%) were observed, with 12 (20%) ultimately requiring an intervention to treat the renal injury. Those subjects who failed nonoperative management had significantly fewer hospital-free days compared to those who did not need a procedure (19.2 ± 8.1 vs. 25.7 ± 4.5, p = 0.002).

CONCLUSIONS

Nearly one in three patients with penetrating renal injuries are currently managed with serial observation, although one in five of these subjects ultimately require either angiographic or surgical treatment. We feel that routine use of early angiography may reduce the failure rate and improve outcomes for patients whose penetrating renal injuries are managed nonoperatively.