Toward a CRISPR-based mouse model of -deficient clear cell kidney cancer: Initial experience and lessons learned.

CRISPR is revolutionizing the ability to do somatic gene editing in mice for the purpose of creating new cancer models. Inactivation of the tumor suppressor gene is the signature initiating event in the most common form of kidney cancer, clear cell renal cell carcinoma (ccRCC). Such tumors are usually driven by the excessive HIF2 activity that arises when the gene product, pVHL, is defective.

Sensitivity of mutant kidney cancers to HIF2 inhibitors does not require an intact p53 pathway.

Inactivation of the VHL tumor suppressor gene is the signature initiating event in clear cell renal cell carcinoma (ccRCC), which is the most common form of kidney cancer. The VHL tumor suppressor protein marks hypoxia-inducible factor 1 (HIF1) and HIF2 for proteasomal degradation when oxygen is present. The inappropriate accumulation of HIF2 drives tumor formation by VHL tumor suppressor protein (pVHL)–defective ccRCC.

AKT Ser/Thr kinase increases V-ATPase-dependent lysosomal acidification in response to amino acid starvation in mammalian cells.

The vacuolar H-ATPase (V-ATPase) is an ATP-dependent proton pump that is essential for cellular homeostasis. V-ATPase activity is controlled by the regulated assembly of the enzyme from its component V and V domains. We previously reported that amino acid starvation rapidly increases V-ATPase assembly and activity in mammalian lysosomes, but the signaling pathways controlling this effect are unknown.

HIF-independent synthetic lethality between CDK4/6 inhibition and VHL loss across species.

Inactivation of the tumor suppressor gene is the signature initiating event in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, and causes the accumulation of hypoxia-inducible factor 2α (HIF-2α). HIF-2α inhibitors are effective in some ccRCC cases, but both de novo and acquired resistance have been observed in the laboratory and in the clinic. Here, we identified synthetic lethality between decreased activity of cyclin-dependent kinases 4 and 6 (CDK4/6) and inactivation in two species (human and ) and across diverse human ccRCC cell lines in culture and xenografts.

Amino Acid Availability Modulates Vacuolar H+-ATPase Assembly.

The vacuolar H(+)-ATPase (V-ATPase) is an ATP-dependent proton pump composed of a peripheral ATPase domain (V1) and a membrane-integral proton-translocating domain (V0) and is involved in many normal and disease processes. An important mechanism of regulating V-ATPase activity is reversible assembly of the V1 and V0 domains. Increased assembly in mammalian cells occurs under various conditions and has been shown to involve PI3K.