Patient-derived organoids (PDOs) serve as invaluable 3D tumor models, retaining the histological complexity and genetic heterogeneity found in primary tumors. However, the limitation of small sample volumes and the lack of tailored platforms have hindered the research using PDOs. Within the tumor microenvironment, cancer-associated fibroblasts play a pivotal role in influencing drug sensitivity. In this study, we introduce an agarose microwell platform designed for PDO-based tumor and tumor microenvironment models, enabling rapid drug screening and resistance studies with small sample volumes. These microwells, constructed using 3D printing molds, feature a U-shaped bottom and 200 μm diameter. We successfully generated co-culture spheroids of non-small cell lung carcinoma (NSCLC) cells, including NCI-H358 or A549, and NSCLC PDOs F231 or F671 with fibroblast cell line, WI-38. Our results demonstrate the production of uniformly-sized spheroids (coefficient of variation 80% after 1 week), and fibroblast-induced drug resistance. The PDOs maintained their viability (>81% after 2 weeks) and continued to proliferate. Notably, when exposed to adagrasib, a KRAS^G12C inhibitor, we observed reduced cytotoxicity in KRAS^G12C-mutant spheroids when co-cultured with fibroblasts or their supernatant. The fibroblast supernatant sustained proliferative signals in tumor models. Taking into account the physical features, viability, and drug resistance acquired through supernatants from the fibroblasts, our platform emerges as a suitable platform for in vitro tumor modeling and the evaluation of drug efficacy using patient-derived tissues.

Patients with high cholesterol and glucose levels are at high risk for cardiovascular disease. The Sterol Regulatory Element Binding Protein (SREBP) system regulates genes involved in lipid, cholesterol and glucose pathways. Autosomal Dominant Hypercholesterolemias (ADHs) are a group of diseases with increased cholesterol levels. They affect 1 out of every 500 individuals. About 20–30% of patients do not present any mutation in the known genes (LDLR, APOB and PCSK9). ADHs constitute a good model to identify the genes involved in the alteration of lipid levels or possible therapeutic targets. In this paper, we studied whether a mutation in the SREBP system could be responsible for ADH and other metabolic alterations present in these patients. Forty-one ADH patients without mutations in the main responsible genes were screened by direct sequencing of SREBP system genes. A luciferase reporter assay of the found mutation and an oral glucose tolerance test in carriers and non-carriers were performed. We found a novel mutation in the SREBF2 gene that increases transcription levels and cosegregates with hypercholesterolemia, and we found increased glucose levels in one family. SREBP2 is known to be involved in cholesterol synthesis, plasma levels and glucose metabolism in humans. The found mutation may involve the SREBF2 gene in hypercholesterolemia combined with hyperglycemia.

Lung cancer is the deadliest neoplasia worldwide. Despite the availability of targeted therapies like tyrosine kinase inhibitors (TKIs) for EGFR-driven tumours in Non-Small Cell Lung Cancer (NSCLC), drug resistance remains a major factor that dramatically cuts life expectancy. Here we identify how increased expression of nicotinamide N-methyltransferase (NNMT) in TKI-resistant cancer cells diverts nicotinamide to synthesise 1-Methylnicotinamide (1-MNA) and lowers NAD⁺ levels that generates a druggable nicotinamide phosphoribosyltransferase (NAMPT) metabolic vulnerability. We also report that high blood levels of 1-MNA, the by-product of NNMT activity, are significantly associated with lower survival rates in EGFR TKI-treated NSCLC patients. Taken together, our findings describe a new and highly specific non-genetic metabolic synthetic lethality for mesenchymal-like tumours, which exposes NAMPT as an in vivo druggable target and establishes 1-MNA as a novel liquid biopsy biomarker to predict and monitor EGFR TKI resistance in NSCLC.

KRAS G12D is a common oncogenic driver mutation in diverse cancers, including non–small cell lung cancer, colorectal cancer, and pancreatic cancer. KRASG12D inhibitors have recently progressed into clinical trials but will likely face innate or acquired drug resistance similar to that which has been observed for KRASG12C inhibitors, such as activation of receptor tyrosine kinases, KRAS independence, and reactivation of RAS–MAPK signaling. This study investigates heterobifunctional small-molecule dual inhibitors that simultaneously target both KRASG12D and protein chaperone HSP90 in KRASG12D-mutated cancer cell lines and patient-derived organoids. Our findings reveal that the efficacy of the clinical-stage KRASG12D inhibitor MRTX1133 varies, with notable resistance being observed in some cell line and organoid models. In contrast, KRASG12D–HSP90 dual inhibitors were found to broadly display superior effectiveness in inducing apoptosis, reducing cell viability, and suppressing key downstream signaling pathways such as AKT and ERK1/2 in MRTX1133-resistant models. The rationale for targeting HSP90, which is preferentially activated in cancer cells, alongside KRASG12D, arises from the ability of HSP90 inhibition to destabilize substrate client proteins that are essential for cancer cell survival and have also been implicated in resistance to KRAS inhibitors. This dual-inhibitor approach presents a promising new strategy to combat de novo and acquired drug resistance in KRASG12D-mutated cancers and potentially paves the way for improved clinical outcomes by addressing the complex molecular mechanisms underlying cancer cell evolution that enables resistance to conventional inhibitors.

While KRAS^G12C inhibitors have shown promising results in clinical activity, acquired resistance remains a significant barrier to durable responses. Combination therapies have been explored to improve the efficacy of KRAS^G12C inhibitors; however, their use is often restricted due to toxicity and limitations in clinically amenable dosing schedules. Transcriptomic profiling and functional assays on acquired resistant models to adagrasib identified an enrichment of HSP90 client proteins in resistant phenotypes, suggesting a therapeutic vulnerability. To address the finding, RNK07421, a novel heterobifunctional molecule, was developed to simultaneously target KRAS^G12C and HSP90-client oncoproteins. Structural and biochemical analyses demonstrated that RNK07421 disrupts KRAS^G12C interactions by inducing a non-natural interface with HSP90, thereby impairing oncogenic signaling. In vitro, RNK07421 effectively suppressed ERK reactivation and reduced viability in KRAS^G12C-mutant cell lines exhibiting either intrinsic or acquired resistance. In vivo, RNK07421 significantly reduced tumor burden in xenograft models, outperforming both monotherapies and combination therapies. These findings highlight dual KRAS^G12C and HSP90 inhibition as a promising strategy to overcome resistance in KRAS^G12C-driven cancers.

Supplementary Figure S2 shows that MRTX1133 treatment activates receptor tyrosine kinases (RTKs) to overcome KRAS G12D inhibition. Specifically, it demonstrates (A) increased phosphorylation and activation of EGFR family members and other RTKs in a model-dependent manner after 72 hours of MRTX1133 treatment, and (B) unchanged KRAS, HRAS, and NRAS mRNA levels in treated G12D-mutated PDOs.