CRISPR/Cas9 targeting of passenger single nucleotide variants in haploinsufficient or essential genes expands cancer therapy prospects.

CRISPR/Cas9 technology has effectively targeted cancer-specific oncogenic hotspot mutations or insertion-deletions. However, their limited prevalence in tumors restricts their application. We propose a novel approach targeting passenger single nucleotide variants (SNVs) in haploinsufficient or essential genes to broaden therapeutic options. By disrupting haploinsufficient or essential genes through the cleavage of DNA in the SNV region using CRISPR/Cas9, we achieved the selective elimination of cancer cells without affecting normal cells. We found that, on average, 44.8% of solid cancer patients are eligible for our approach, a substantial increase compared to the 14.4% of patients with CRISPR/Cas9-applicable oncogenic hotspot mutations. Through in vitro and in vivo experiments, we validated our strategy by targeting a passenger mutation in the essential ribosomal gene RRP9 and haploinsufficient gene SMG6. This demonstrates the potential of our strategy to selectively eliminate cancer cells and expand therapeutic opportunities.

Discovery of a novel NAMPT inhibitor that selectively targets NAPRT-deficient EMT-subtype cancer cells and alleviates chemotherapy-induced peripheral neuropathy.

Background: Exploiting synthetic lethality (SL) relationships between protein pairs has emerged as an important avenue for the development of anti-cancer drugs. Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme of the NAD+ salvage pathway, having an SL relationship with nicotinic acid phosphoribosyltransferase (NAPRT), the key enzyme in the NAD+ Preiss-Handler pathway. NAMPT inhibitor holds clinical potential not only as a promising cancer treatment but also as a means of protection against chemotherapy-induced-peripheral-neuropathy (CIPN). However, as NAD+ is essential for normal cells, the clinical use of NAMPT inhibitors is challenging. This study aimed to identify a novel NAMPT inhibitor with enhanced selective cytotoxicity against NAPRT-deficient cancer cells as well as prominent efficacy in alleviating CIPN. Methods: We began by conducting drug derivatives screening in a panel of lung cancer cell lines to select an agent with the broadest therapeutic window between the NAPRT-negative and-positive cancer cell lines. Both in vitro and In vivo comparative analyses were conducted between A4276 and other NAMPT inhibitors to evaluate the NAPRT-negative cancer cell selectivity and the underlying distinct NAMPT inhibition mechanism of A4276. Patient-derived tumor transcriptomic data and protein levels in various cancer cell lines were analyzed to confirm the correlation between NAPRT depletion and epithelial-to-mesenchymal transition (EMT)-like features in various cancer types. Finally, the efficacy of A4276 for axonal protection and CIPN remedy was examined in vitro and in vivo. Results: The biomarker-driven phenotypic screening led to a discovery of A4276 with prominent selectivity against NAPRT-negative cancer cells compared with NAPRT-positive cancer cells and normal cells. The cytotoxic effect of A4276 on NAPRT-negative cells is achieved through its direct binding to NAMPT, inhibiting its enzymatic function at an optimal and balanced level allowing NAPRT-positive cells to survive through NAPRT-dependent NAD+ synthesis. NAPRT deficiency serves as a biomarker for the response to A4276 as well as an indicator of EMT-subtype cancer in various tumor types. Notably, A4276 protects axons from Wallerian degeneration more effectively than other NAMPT inhibitors by decreasing NMN-to-NAD+ ratio. Conclusion: This study demonstrates that A4276 selectively targets NAPRT-deficient EMT-subtype cancer cells and prevents chemotherapy-induced peripheral neuropathy, highlighting its potential as a promising anti-cancer agent for use in cancer monotherapy or combination therapy with conventional chemotherapeutics.

Snail acetylation by autophagy-derived acetyl-coenzyme A promotes invasion and metastasis of KRAS-LKB1 co-mutated lung cancer cells.

BACKGROUND: Autophagy is elevated in metastatic tumors and is often associated with active epithelial-to-mesenchymal transition (EMT). However, the extent to which EMT is dependent on autophagy is largely unknown. This study aimed to identify the mechanisms by which autophagy facilitates EMT. METHODS: We employed a liquid chromatography-based metabolomic approach with kirsten rat sarcoma viral oncogene (KRAS) and liver kinase B1 (LKB1) gene co-mutated (KL) cells that represent an autophagy/EMT-coactivated invasive lung cancer subtype for the identification of metabolites linked to autophagy-driven EMT activation. Molecular mechanisms of autophagy-driven EMT activation were further investigated by quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting analysis, immunoprecipitation, immunofluorescence staining, and metabolite assays. The effects of chemical and genetic perturbations on autophagic flux were assessed by two orthogonal approaches: microtubule-associated protein 1A/1B-light chain 3 (LC3) turnover analysis by Western blotting and monomeric red fluorescent protein-green fluorescent protein (mRFP-GFP)-LC3 tandem fluorescent protein quenching assay. Transcription factor EB (TFEB) activity was measured by coordinated lysosomal expression and regulation (CLEAR) motif-driven luciferase reporter assay. Experimental metastasis (tail vein injection) mouse models were used to evaluate the impact of calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2) or ATP citrate lyase (ACLY) inhibitors on lung metastasis using IVIS luciferase imaging system. RESULTS: We found that autophagy in KL cancer cells increased acetyl-coenzyme A (acetyl-CoA), which facilitated the acetylation and stabilization of the EMT-inducing transcription factor Snail. The autophagy/acetyl-CoA/acetyl-Snail axis was further validated in tumor tissues and in autophagy-activated pancreatic cancer cells. TFEB acetylation in KL cancer cells sustained pro-metastatic autophagy in a mammalian target of rapamycin complex 1 (mTORC1)-independent manner. Pharmacological inhibition of this axis via CAMKK2 inhibitors or ACLY inhibitors consistently reduced the metastatic capacity of KL cancer cells in vivo. CONCLUSIONS: This study demonstrates that autophagy-derived acetyl-CoA promotes Snail acetylation and thereby facilitates invasion and metastasis of KRAS-LKB1 co-mutated lung cancer cells and that inhibition of the autophagy/acetyl-CoA/acetyl-Snail axis using CAMKK2 or ACLY inhibitors could be a potential therapeutic strategy to suppress metastasis of KL lung cancer.

Establishment of reference standards for multifaceted mosaic variant analysis.

Detection of somatic mosaicism in non-proliferative cells is a new challenge in genome research, however, the accuracy of current detection strategies remains uncertain due to the lack of a ground truth. Herein, we sought to present a set of ultra-deep sequenced WES data based on reference standards generated by cell line mixtures, providing a total of 386,613 mosaic single-nucleotide variants (SNVs) and insertion-deletion mutations (INDELs) with variant allele frequencies (VAFs) ranging from 0.5% to 56%, as well as 35,113,417 non-variant and 19,936 germline variant sites as a negative control. The whole reference standard set mimics the cumulative aspect of mosaic variant acquisition such as in the early developmental stage owing to the progressive mixing of cell lines with established genotypes, ultimately unveiling 741 possible inter-sample relationships with respect to variant sharing and asymmetry in VAFs. We expect that our reference data will be essential for optimizing the current use of mosaic variant detection strategies and for developing algorithms to enable future improvements.

Integrated pharmaco-proteogenomics defines two subgroups in isocitrate dehydrogenase wild-type glioblastoma with prognostic and therapeutic opportunities.

The prognostic and therapeutic relevance of molecular subtypes for the most aggressive isocitrate dehydrogenase 1/2 (IDH) wild-type glioblastoma (GBM) is currently limited due to high molecular heterogeneity of the tumors that impedes patient stratification. Here, we describe a distinct binary classification of IDH wild-type GBM tumors derived from a quantitative proteomic analysis of 39 IDH wild-type GBMs as well as IDH mutant and low-grade glioma controls. Specifically, GBM proteomic cluster 1 (GPC1) tumors exhibit Warburg-like features, neural stem-cell markers, immune checkpoint ligands, and a poor prognostic biomarker, FKBP prolyl isomerase 9 (FKBP9). Meanwhile, GPC2 tumors show elevated oxidative phosphorylation-related proteins, differentiated oligodendrocyte and astrocyte markers, and a favorable prognostic biomarker, phosphoglycerate dehydrogenase (PHGDH). Integrating these proteomic features with the pharmacological profiles of matched patient-derived cells (PDCs) reveals that the mTORC1/2 dual inhibitor AZD2014 is cytotoxic to the poor prognostic PDCs. Our analyses will guide GBM prognosis and precision treatment strategies.