Supplemental Figure S9 | Supporting data for single cell RNA sequencing of CAR-T in 3D co-cultures with PDOTS.

Supplemental Figure S10 | Supporting data for single cell RNA sequencing of native tumor-infiltrating lymphocytes following CAR-T challenge in 3D co-cultures with PDOTS.

PROTACs are commonly developed by linking E3 ligase-recruiting ligands to established inhibitors of a protein target, often resulting in degraders that retain enzymatic inhibition. Type II inhibition of cyclin-dependent kinases (CDKs) has been challenging, as reported compounds generally exhibit weak biochemical potency and limited cellular activity. Consistent with these limitations, most reported CDK degraders have been derived from type I ATP-competitive inhibitors. Here, we explored whether targeted protein degradation could enable functional CDK targeting from a type II kinase scaffold. Using the multikinase inhibitor regorafenib as a starting scaffold, we generated a focused library of CRL4CRBN-recruiting bifunctional molecules and profiled their degradation activity using quantitative mass spectrometry-based proteomics. This analysis unexpectedly revealed CDK5 and CDK6, kinases not inhibited by the parent scaffold, as degradation targets. Optimization of this series led to JHK-02-108-2, a selective CDK6 degrader that does not display a hook effect and promotes potent CDK6 degradation despite weak CDK6 binding and negligible CDK6 inhibition. In cellular models of acute myeloid leukemia (AML) and glioblastoma, JHK-02-108-2 induced sustained G1 arrest and reduced phosphorylation of the retinoblastoma protein. Interestingly, subtle modifications in PROTAC architecture redirected degradation selectivity, yielding JHK-02-102-1 as a selective type II CDK5 degrader derived from the same scaffold. Together, these findings establish the first type II inhibitor-derived selective CDK6 degrader and demonstrate that targeted protein degradation can enable functional CDK targeting from type II kinase scaffolds.

Supplemental Figure S3 | Supporting data for ex vivo profiling of B7-H3.CAR-T cells using PDOTS.

Supplemental Figure S5 | Supporting data that targeting TBK1 prevents CAR-T cell dysfunction.

Supplementary Figure S1 | Supporting data demonstrating B7-H3 expression in melanoma and other cancers.

Supplemental Figure S6 | Supporting data that targeting TBK1 prevents CAR-T cell dysfunction.

PDOTS patient data (accompanying Fig. 1)

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting side effect of cancer treatment, yet the lack of predictive human models continues to hinder therapeutic progress. Here, we establish a scalable and reproducible model of paclitaxel-induced axon degeneration and neurotoxicity in human iPSC-derived sensory neurons, suitable for high-throughput identification of neuroprotective compounds. Using this platform, we screen a library of 192 kinase inhibitors and identify 19 hits that commonly inhibit three STE20 kinases—MAP4K4, MINK1, and TNIK. Genetic knockdown studies reveal that multi-kinase inhibition of these kinases is required for neuroprotection against paclitaxel. Consistently, selective pharmacological inhibition of the identified STE20 kinases rescues paclitaxel-induced axon degeneration in iPSC-derived sensory neurons and primary human dorsal root ganglia (DRG) and preserves intraepidermal nerve fiber density in a mouse model of CIPN. Together, these findings establish a translational human sensory neuron platform that enables target validation and drug discovery for CIPN.

Supplemental Figure S11 | Supporting data that targeting TBK1 sensitizes cancer cells to CAR-T cell-derived TNFα/IFNγ.

Supplemental Figure S7 | Supporting data that targeting TBK1 prevents CAR-T cell dysfunction.

Supplemental Figure S4 | Supporting data for ex vivo profiling of PD-1 blockade and TBK1 inhibition in combination with B7-H3.CAR-T cells using PDOTS.

Despite decades of research, current understanding of the spectrum of targets bound by kinase inhibitors remains incomplete. This complicates mechanism of action studies, drug repurposing, and development of new therapies. Here, we describe kinome-wide profiling of an optimal kinase library (OKL) comprising 192 small molecules selected based on stage of clinical development, chemical diversity, and target coverage. Our results show that polypharmacology is widespread and independent of regulatory approval. The generally understood ("assigned") targets of approved molecules are not necessarily the most potently inhibited and off-targets include multiple understudied kinases. Moreover, median selectivity has not increased over time We illustrate how an OKL in combination with detailed kinome profiling can be used to identify potential toxicity targets, repurpose anti-inflammatory drugs for neurodegenerative and infectious diseases, and perform chemical genetic studies. Our studies also highlight how much remains to be discovered about the chemistry and biology of one of the largest classes of human therapeutics.

Despite advances in precision oncology, effective personalized treatments are still lacking for most patients with cancer1. The Cancer Dependency Map (DepMap) accelerates this field by systematically identifying cancer vulnerabilities in diverse preclinical models. Data from over 1,300 cell lines have led to the discovery of new therapeutic strategies across multiple tumour types2. However, mapping cancer vulnerabilities using traditional cell lines has limitations, including insufficient cancer subtype representation and the impact of culture conditions on perturbation responses. Here we perform 147 genome-scale CRISPR screens and multi-omic characterizations of next-generation (NextGen) cancer models (organoids and spheroids) across 10 cancer types. This strategy enables the expansion of DepMap to cover new genomic and molecular subtypes and to identify new biomarker-associated vulnerabilities. These new models also preserve transcriptional programs that are silenced in traditional cell lines and facilitate the discovery of specific gene dependencies associated with these programs. Comparisons of traditional and NextGen cancer models enable further identification of distinct effects of growth format and culture medium on gene essentiality. The integrated dataset combines data from both model types to offer a valuable, expansive resource for exploring cancer vulnerabilities and is accessible via the DepMap portal.

Supplementary Figure S2 | Supporting data for the In vitro characterization and efficacy of B7-H3.CAR-T cells.

Supplemental Figure S8 | Supporting data that targeting TBK1 prevents CAR-T cell dysfunction.

The Library of Integrated Network-based Cellular Signatures (LINCS), an NIH Common Fund program, has cataloged and analyzed cellular function and molecular activity profiles in response to >80,000 perturbing agents that are potentially disruptive to cells. Because of the importance of proteins and their modifications to the response of specific cellular perturbations, four of the six LINCS centers have included significant proteomics efforts in the characterization of the resulting phenotype. This manuscript aims to describe this effort and the data harmonization and integration of the LINCS proteomics data discussed in recent LINCS papers.

Inhibiting oxidative stress response (OSR) proteins has been suggested as a therapeutic strategy in triple negative breast cancer (TNBC). However, the cell type specificity and spatial distribution of OSR genes and proteins, such as GCLC and NQO1, is unknown. Using single cell and spatial transcriptomics datasets we found that OSR genes were highly expressed in TNBC tumor cells, which localized in spatial clusters. Multiplex immunofluorescence imaging of 345 TNBC samples from 186 patients demonstrated that OSR proteins GCLC and NQO1 exhibit distinct expression profiles across tumor, immune, and stromal cell populations and are elevated in inflamed histological regions. Tumor cell OSR protein expression was associated with the composition of the adjacent cellular neighborhood. Furthermore, we identified GCLC and vimentin positive (GCLC+VIM+) mesenchymal-like tumor cells, residing near immune cells and exhibiting increased proliferation and decreased anastasis signatures, suggesting sensitivity to chemotherapy. Across a panel of thirteen TNBC cell lines, GCLC expression was positively correlated with sensitivity to cisplatin. Cox regression analysis revealed that patients with higher proportions of GCLC+VIM+ tumor cells had a longer overall survival. Collectively, our results demonstrate that individual OSR proteins are expressed in distinct microenvironments and tumor cell states, potentially contributing to patient outcomes. ### Competing Interest Statement Peter K. Sorger is a co-founder and member of the BOD of Glencoe Software, member of the SAB for RareCyte, Reverb Therapeutics and Montai Health, and consultant for Merck; he holds equity in Glencoe and RareCyte. The other authors declare no potential conflicts of interest. Ludwig Cancer Center at Harvard The Gray Foundation The Mark Foundation for Cancer Research, https://ror.org/00v7th354 American Cancer Society, https://ror.org/02e463172, PF–24–1316850–01–CD

Novel therapeutic strategies are needed to improve the efficacy of chimeric antigen receptor (CAR) T cells as a treatment of solid tumors. Multiple tumor microenvironmental factors are thought to contribute to resistance to CAR T-cell therapy in solid tumors, and appropriate model systems to identify and examine these factors using clinically relevant biospecimens are limited. In this study, we examined the activity of B7-H3-directed CAR T cells (B7-H3.CAR-T) using 3D microfluidic cultures of patient-derived organotypic tumor spheroids (PDOTS) and then confirmed the activity of B7-H3.CAR T cells in PDOTS. Although B7-H3 expression in PDOTS was associated with B7-H3.CAR-T sensitivity, mechanistic studies revealed dynamic upregulation of co-inhibitory receptors on CAR T-cells following target cell encounter that led to CAR T-cell dysfunction and limited efficacy against B7-H3-expressing tumors. PD-1 blockade restored CAR T-cell activity in monotypic and organotypic tumor spheroids with improved tumor control and upregulation of effector cytokines. Given the emerging role of TANK-binding kinase 1 (TBK1) as an immune evasion gene, we examined the effect of TBK1 inhibition on CAR T-cell efficacy. Similar to PD-1 blockade, TBK1 inhibition restored CAR T-cell activity in monotypic and organotypic tumor spheroids, prevented CAR T-cell dysfunction, and enhanced CAR T-cell proliferation. Inhibition or deletion of TBK1 also enhanced the sensitivity of cancer cells to immune-mediated killing. Taken together, our results demonstrate the feasibility and utility of ex vivo profiling of CAR T cells using PDOTS and suggest that targeting TBK1 could be used to enhance CAR T-cell efficacy by overcoming tumor-intrinsic and -extrinsic resistance mechanisms.

Cyclin-dependent kinase 7, along with cyclin H and MAT1, forms the CDK-activating complex (CAK), which directs cell cycle progression via T-loop phosphorylation of cell cycle CDKs. Pharmacological inhibition of CDK7 leads to selective anti-cancer effects in cellular and in vivo models, motivating several ongoing clinical investigations of this target. Current CDK7 inhibitors are either reversible or covalent inhibitors of its catalytic activity. We hypothesized that small molecule targeted protein degradation (TPD) might result in differentiated pharmacology due to the loss of scaffolding functions. Here, we report the design and characterization of a potent CDK7 degrader that is comprised of an ATP-competitive CDK7 binder linked to a CRL2VHL recruiter. JWZ-5-13 effectively degrades CDK7 in multiple cancer cells and leads to a potent inhibition of cell proliferation. Additionally, compound JWZ-5-13 displayed bioavailability in a pharmacokinetic study conducted in mice. Therefore, JWZ-5-13 is a useful chemical probe to investigate the pharmacological consequences of CDK7 degradation.