Multiomic profiling of breast cancer cells uncovers stress MAPK-associated sensitivity to AKT degradation.

More than 50% of human tumors display hyperactivation of the serine/threonine kinase AKT. Despite evidence of clinical efficacy, the therapeutic window of the current generation of AKT inhibitors could be improved. Here, we report the development of a second-generation AKT degrader, INY-05-040, which outperformed catalytic AKT inhibition with respect to cellular suppression of AKT-dependent phenotypes in breast cancer cell lines. A growth inhibition screen with 288 cancer cell lines confirmed that INY-05-040 had a substantially higher potency than our first-generation AKT degrader (INY-03-041), with both compounds outperforming catalytic AKT inhibition by GDC-0068. Using multiomic profiling and causal network integration in breast cancer cells, we demonstrated that the enhanced efficacy of INY-05-040 was associated with sustained suppression of AKT signaling, which was followed by induction of the stress mitogen-activated protein kinase (MAPK) c-Jun N-terminal kinase (JNK). Further integration of growth inhibition assays with publicly available transcriptomic, proteomic, and reverse phase protein array (RPPA) measurements established low basal JNK signaling as a biomarker for breast cancer sensitivity to AKT degradation. Together, our study presents a framework for mapping the network-wide signaling effects of therapeutically relevant compounds and identifies INY-05-040 as a potent pharmacological suppressor of AKT signaling.

PI3K drives the de novo synthesis of coenzyme A from vitamin B5.

In response to hormones and growth factors, the class I phosphoinositide-3-kinase (PI3K) signalling network functions as a major regulator of metabolism and growth, governing cellular nutrient uptake, energy generation, reducing cofactor production and macromolecule biosynthesis1. Many of the driver mutations in cancer with the highest recurrence, including in receptor tyrosine kinases, Ras, PTEN and PI3K, pathologically activate PI3K signalling2,3. However, our understanding of the core metabolic program controlled by PI3K is almost certainly incomplete. Here, using mass-spectrometry-based metabolomics and isotope tracing, we show that PI3K signalling stimulates the de novo synthesis of one of the most pivotal metabolic cofactors: coenzyme A (CoA). CoA is the major carrier of activated acyl groups in cells4,5 and is synthesized from cysteine, ATP and the essential nutrient vitamin B5 (also known as pantothenate)6,7. We identify pantothenate kinase 2 (PANK2) and PANK4 as substrates of the PI3K effector kinase AKT8. Although PANK2 is known to catalyse the rate-determining first step of CoA synthesis, we find that the minimally characterized but highly conserved PANK49 is a rate-limiting suppressor of CoA synthesis through its metabolite phosphatase activity. Phosphorylation of PANK4 by AKT relieves this suppression. Ultimately, the PI3K-PANK4 axis regulates the abundance of acetyl-CoA and other acyl-CoAs, CoA-dependent processes such as lipid metabolism and proliferation. We propose that these regulatory mechanisms coordinate cellular CoA supplies with the demands of hormone/growth-factor-driven or oncogene-driven metabolism and growth.

Determinants of Risk-Aligned Bladder Cancer Surveillance-Mixed-Methods Evaluation Using the Tailored Implementation for Chronic Diseases Framework.

PURPOSE: For many patients with cancer, the frequency of surveillance after primary treatment depends on the risk for cancer recurrence or progression. Lack of risk-aligned surveillance means too many unnecessary surveillance procedures for low-risk patients and not enough for high-risk patients. Using bladder cancer as an example, we examined whether practice determinants differ between Department of Veterans Affairs sites where risk-aligned surveillance was more (risk-aligned sites) or less common (need improvement sites). METHODS: We used our prior quantitative data to identify two risk-aligned sites and four need improvement sites. We performed semistructured interviews with 40 Veterans Affairs staff guided by the Tailored Implementation for Chronic Diseases framework that were deductively coded. We integrated quantitative data (risk-aligned site v need improvement site) and qualitative data from interviews, cross-tabulating salient determinants by site type. RESULTS: There were 14 participants from risk-aligned sites and 26 participants from need improvement sites. Irrespective of site type, we found a lack of knowledge on guideline recommendations. Additional salient determinants at need improvement sites were a lack of resources ("the next available without overbooking is probably seven to eight weeks out") and an absence of routines to incorporate risk-aligned surveillance ("I have my own guidelines that I've been using for 35 years"). CONCLUSION: Knowledge, resources, and lack of routines were salient barriers to risk-aligned bladder cancer surveillance. Implementation strategies addressing knowledge and resources can likely contribute to more risk-aligned surveillance. In addition, reminders for providers to incorporate risk into their surveillance plans may improve their routines.