Cancer Genetics (United States)

Unlike genomic instability, the implications of proteomic instability in cancer remain ambiguous. By governing the proteotoxic stress response, heat shock factor 1 (HSF1) sustains proteomic stability upon environmental insults. Apart from its importance to stress resistance and survival, HSF1 is emerging as a powerful oncogenic enabler. In the Neurofibromatosis type I (NF1)-deficient malignant peripheral nerve sheath tumor (MPNST) cells, HSF1 depletion triggered protein polyubiquitination, aggregation, and even tumor-suppressive amyloidogenesis. In contrast, HSF1 is dispensable for the proteome of non-transformed human Schwann cells. Mechanistically, HSF1 defends the essential mitochondrial chaperone HSP60 against the direct assault from soluble amyloid oligomers. To survive and adapt to compromised protein quality, owing to HSF1 deficiency, MPNST cells mobilized JNK to repress mTORC1 and protein translation, thereby attenuating protein quantity to alleviate proteomic imbalance. mTORC1 stimulation, via either pharmacological JNK blockade, genetic TSC2 depletion, or leucine supplementation, markedly aggravated the proteomic imbalance elicited by HSF1 deficiency. This catastrophic imbalance instigated pronounced cell death partly through unchecked amyloidogenesis, thereby exerting tumor suppression in both MPNST and melanoma models in vivo. Thus, HSF1 safeguards the cancer proteome to enable the oncogenic potential of mTORC1. This proof-of-principle study highlights provoking proteomic catastrophe as a next-generation therapeutic concept for combating malignancy.

Proteolysis-targeting chimeras (PROTACs) and degraders have been developed against the hRpn13 fragment hRpn13Pru that is present in various cancer types. Testing the performance of these hRpn13Pru-targeting compounds in pharmacokinetic and efficacy studies has been stymied, however, by their poor solubility. Here, we develop a rapid and cost-effective platform to Screen and Characterize small molecule Nanosuspensions (SCaN). We discovered that the hRpn13Pru degrader XL44 adopts a crystalline state, preventing its bioavailability. The first phase of SCaN screens vehicles to identify lead XL44 nanosuspension formulations based on particle size consistency, including in biorelevant media, while the second phase evaluates stability over time. The lead nanosuspensions are then advanced to the third phase of SCaN to assess their physical and colloidal stability. This pipeline allows the formulation of poorly soluble compounds for single-dose pharmacokinetic and pilot multidose tumor mouse studies. We additionally analyzed our XL44 formulation morphologically by atomic force microscopy to find that the XL44 nanoparticles are predominantly globular, with a small population of rod-like particles. Using the optimal nanosuspension determined by SCaN, XL44 slowed tumor growth in a myeloma xenograft model at 35% inhibition with a 48-72 mg/kg treatment regimen. This case study is the first in vivo demonstration that hRpn13Pru-targeting degraders can inhibit tumor growth, and the efficacy shown here motivates the development of more potent hRpn13Pru degraders. Broadly, our SCaN platform is designed for poorly soluble drug candidates to allow for pilot in vivo testing.

Background:Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine cancer with limited treatment options and poor prognosis. Identifying novel therapeutic targets requires understanding the molecular drivers of ACC progression and establishing translational models for preclinical validation.Results:Matrix metalloproteinase-14 (MMP-14) is the most highly expressed MMP in ACC, and high MMP-14 expression is associated with worse overall and disease-free survival. We demonstrate that MMP-14 is essential for ACC cell survival and serves an unexpected role in maintaining genome stability. Genetic silencing or pharmacologic inhibition of MMP-14 significantly reduced viability in both NCI-H295R cells and patient-derived tumor organoids (PTOs). MMP-14 knockdown induced CHK1 activation and S-phase checkpoint arrest. Mechanistically, MMP-14 translocates to the nucleus and binds to chromatin following DNA damage induced by ionizing radiation or cisplatin. Loss of MMP-14 resulted in accumulation of DNA double-strand breaks, as evidenced by increased γH2AX foci, and impaired non-homologous end joining (NHEJ)-mediated repair.Conclusions:These findings reveal a novel nuclear function for MMP-14 in DNA repair and identify MMP-14 as a promising therapeutic target in ACC. Targeting MMP-14 may sensitize ACC tumors to DNA-damaging chemotherapy by impairing the repair of therapy-induced lesions.

Single vs multigene molecular testing modalities for lung cancer offer distinct advantages and risks. We examined lung cancer cases with clinically requested ultrarapid EGFR testing to (1) identify clinical features of rapid tested cases and their association with EGFR mutations, (2) evaluate performance of single-gene and multigene panel testing for ultrarapid tested patients, and (3) estimate laboratory costs and clinical outcomes. We include all retrospectively identified lung cancer patients who had ultrarapid Idylla EGFR testing during the study period. Demographic data were retrieved from clinical charts, and cost estimates were obtained from the BC Cancer Genetics and Genomics Laboratory. Of the 109 ultrarapid tests, 94 (86%) were technically successful, yielding a positive or negative result. Of these, 62 tests (66%) identified an EGFR mutation. Patients with negative or failed testing were offered panel sequencing (n = 47, 43%). Ultrarapid testing had a median 1-day turnaround time and 95% sensitivity for EGFR mutation detection relative to panel sequencing. East/Southeast Asian ethnicity and female sex were significantly associated with EGFR mutation positivity in a multivariate logistic regression model (P = .0001 and .029, respectively). The mean molecular testing cost per ultrarapid tested patient, including panel sequencing for cases with negative/failed rapid tests, was $550.53 (SD: $284), slightly less than the $571 cost for panel sequencing. Single-gene testing of patients with urgent clinical need or high probability of mutation may allow a rapid time to treatment at similar testing costs.