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Author(s): Amritha Nair [1, 2]; Hsiang-Ching Chung [1, 2, 3]; Tingting Sun [1, 2]; Siddhartha Tyagi [1, 2]; Lacey E Dobrolecki [4]; Rocio Dominguez-Vidana [1, 2, 3]; Sarah J Kurley [...]

MYC (also known as c-MYC) overexpression or hyperactivation is one of the most common drivers of human cancer. Despite intensive study, the MYC oncogene remains recalcitrant to therapeutic inhibition. MYC is a transcription factor, and many of its protumorigenic functions have been attributed to its ability to regulate gene expression programs (1-3). Notably, oncogenic MYC activation has also been shown to increase total RNA and protein production in many tissue and disease contexts (4-7). While such increases in RNA and protein production may endow cancer cells with pro-tumour hallmarks, this increase in synthesis may also generate new or heightened burden on MYC-driven cancer cells to process these macromolecules properly (8). Here we discover that the spliceosome is a new target of oncogenic stress in MYC-driven cancers. We identify BUD31 as a MYC-synthetic lethal gene in human mammary epithelial cells, and demonstrate that BUD31 is a component of the core spliceosome required for its assembly and catalytic activity. Core spliceosomal factors (such as SF3B1 and U2AF1) associated with BUD31 are also required to tolerate oncogenic MYC. Notably, MYC hyperactivation induces an increase in total precursor messenger RNA synthesis, suggesting an increased burden on the core spliceosome to process pre-mRNA. In contrast to normal cells, partial inhibition of the spliceosome in MYC-hyperactivated cells leads to global intron retention, widespread defects in pre-mRNA maturation, and deregulation of many essential cell processes. Notably, genetic or pharmacological inhibition of the spliceosome in vivo impairs survival, tumorigenicity and metastatic proclivity of MYC-dependent breast cancers. Collectively, these data suggest that oncogenic MYC confers a collateral stress on splicing, and that components of the spliceosome may be therapeutic entry points for aggressive MYC-driven cancers., To discover genes and cellular processes required to tolerate oncogenic MYC expression, we previously performed a genome-wide MYC-synthetic lethal screen in human mammary epithelial cells (HMECs) engineered with an inducible [...]

Metabolic profiling of cancer cells has recently been established as a promising tool for the development of therapies and identification of cancer biomarkers. Here we characterized the metabolomic profile of human breast tumors and uncovered intrinsic metabolite signatures in these tumors using an untargeted discovery approach and validation of key metabolites. The oncometabolite 2-hydroxyglutarate (2HG) accumulated at high levels in a subset of tumors and human breast cancer cell lines. We discovered an association between increased 2HG levels and MYC pathway activation in breast cancer, and further corroborated this relationship using MYC overexpression and knockdown in human mammary epithelial and breast cancer cells. Further analyses revealed globally increased DNA methylation in 2HG-high tumors and identified a tumor subtype with high tissue 2HG and a distinct DNA methylation pattern that was associated with poor prognosis and occurred with higher frequency in African-American patients. Tumors of this subtype had a stem cell-like transcriptional signature and tended to overexpress glutaminase, suggestive of a functional relationship between glutamine and 2HG metabolism in breast cancer. Accordingly, 13C-labeled glutamine was incorporated into 2HG in cells with aberrant 2HG accumulation, whereas pharmacologic and siRNA-mediated glutaminase inhibition reduced 2HG levels. Our findings implicate 2HG as a candidate breast cancer oncometabolite associated with MYC activation and poor prognosis., Introduction Gene expression profiling studies of breast cancer led to the discovery of disease subtypes and expression patterns that are predictive of disease outcome (1-3). Recently, metabolomics emerged as a [...]

Treatment decisions for patients with cutaneous squamous cell carcinoma (cSCC) are traditionally based upon clinicopathologic risk factors and staging systems. Due to the accuracy limitations of these resources in predicting poor outcomes, there is a clinically significant need for more accurate methods of risk assessment. The 40-gene expression profile (40-GEP) test was developed to augment metastatic risk prediction of high-risk cSCC patients and has been validated in two independent, multi-center studies involving over 1,000 patients. This study substantiates that the 40-GEP is appropriately utilized by clinicians and that the personalized risk-stratification results are impactful in guiding risk-aligned patient management. [ABSTRACT FROM AUTHOR]

Aim: To clinically validate the 40-gene expression profile (40-GEP) test for cutaneous squamous cell carcinoma patients and evaluate coupling the test with individual clinicopathologic risk factor-based assessment methods. Patients & methods: In a 33-site study, primary tumors with known patient outcomes were assessed under clinical testing conditions (n = 420). The 40-GEP results were integrated with clinicopathologic risk factors. Kaplan-Meier and Cox regression analyses were performed for metastasis. Results: The 40-GEP test demonstrated significant prognostic value. Risk classification was improved via integration of 40-GEP results with clinicopathologic risk factor-based assessment, with metastasis rates near the general cutaneous squamous cell carcinoma population for class 1 and ≥50% for class 2B. Conclusion: Combining molecular profiling with clinicopathologic risk factor assessment enhances stratification of cutaneous squamous cell carcinoma patients and may inform decision-making for risk-appropriate management strategies. [ABSTRACT FROM AUTHOR]

Objective: Over 50% of newly diagnosed cutaneous squamous cell carcinoma (cSCC) lesions occur in the head and neck (cSCC‐HN), and metastasis to nodal basins in this region further complicates surgical and adjuvant treatment. The current study addressed whether the 40‐gene expression profile (40‐GEP) test can predict metastatic risk in cSCC‐HN with improved accuracy and provide independent prognostic value to complement current risk assessment methods. Study Design: Multicenter, retrospective cohort study. Methods: Formalin‐fixed paraffin‐embedded primary tumor tissue and associated clinical data from patients with cSCC‐HN (n = 278) were collected from 33 independent centers. Samples were analyzed via the 40‐GEP test. Cases were staged per American Joint Committee on Cancer, Eighth Edition (AJCC8) and Brigham and Women's Hospital (BWH) criteria after comprehensive medical record and pathology report review. Metastasis‐free survival (MFS) rates were determined, and risk factors were analyzed via Cox regression. Results: The 40‐GEP test classified the cohort into low (Class 1, n = 126; 45.3%), moderate (Class 2A, n = 134; 48.2%), and high (Class 2B, n = 18; 6.5%) metastatic risk at 3 years postdiagnosis. Regional/distant metastasis occurred in 54 patients (19.4%). MFS rates were 92.1% (Class 1), 76.1% (Class 2A), and 44.4% (Class 2B; p <.0001). Multivariate analysis of 40‐GEP results with AJCC8 or BWH tumor stage, or clinicopathologic risk factors, demonstrated independent prognostic value of the 40‐GEP test (p <.03). Accuracy of predicting metastatic risk was also improved using 40‐GEP classification (p <.02). Conclusions: Improved metastatic risk stratification through the 40‐GEP test could complement cSCC‐HN risk assessment for better‐informed decision‐making for treatment and surveillance and ultimately improve patient outcomes. Level of Evidence: 3 [ABSTRACT FROM AUTHOR]

Standard of care for high‐risk cutaneous squamous cell carcinoma (cSCC) is surgical excision of the primary lesion with clear margins when possible, and additional resection of positive margins when feasible. Even with negative margins, certain high‐risk factors warrant consideration of adjuvant therapy. However, which patients might benefit from adjuvant therapy is unclear, and supporting evidence is conflicting and limited to mostly small retrospective cohorts. Here, we review literature from the last decade regarding adjuvant radiation therapy and systemic therapy in high‐risk cSCC, including recent and current trials and the role of immune checkpoint inhibitors. We demonstrate evidence gaps in adjuvant therapy for high‐risk cSCC and the need for prognostic tools, such as gene expression profiling, to guide patient selection. More large‐cohort clinical studies are needed for collecting high‐quality, evidence‐based data for determining which patients with high‐risk cSCC may benefit from adjuvant therapy and which therapy is most appropriate for patient management. [ABSTRACT FROM AUTHOR]

Objective: To integrate gene expression profiling into the management of high-risk cutaneous squamous cell carcinoma (cSCC) within the National Comprehensive Cancer Network (NCCN) guidelines to improve risk-aligned management recommendations.Methods: A cohort of 300 NCCN-defined high-risk cSCC patients, along with the American Joint Committee on Cancer (AJCC) T stage, Brigham and Women's Hospital (BWH) T stage, and known patient outcomes were analyzed. Risk classifications using a validated 40-gene expression profile (40-GEP) test and T stage were applied to NCCN patient management guidelines. Risk-directed patient management recommendations within the NCCN guidelines framework were aligned based on risk for metastasis.Results: Of the 300 NCCN high-risk cSCC patients, 159 (53.0%) were 40-GEP Class 1 and AJCC T1-T2, and 173 (57.7%) were Class 1 and BWH T1-2a, indicating low risk for metastasis and, thereby, suggesting low management intensity. The 40-GEP integration suggested high intensity management for only 24 (8.0%) patients (all Class 2B), and moderate intensity management for the remainder of the cohort.Conclusions: The 40-GEP test can be integrated within existing NCCN guideline recommendations for managing cSCC patients to help refine risk-directed management decisions. Integration of the 40-GEP test would allow >50% of this NCCN-defined high-risk cohort to be managed with the lowest intensity recommendations within the broad NCCN guidelines. High intensity management was deemed risk-appropriate for a small subpopulation (8.0%). This study demonstrates that the 40-GEP test, in combination with T stage, has clinical utility to impact patient management decisions in NCCN high-risk cSCC for improving risk-aligned management within the NCCN guidelines framework. [ABSTRACT FROM AUTHOR]

Objective: To determine how results from a prognostic 40-gene expression profiling (40-GEP) test would impact clinician management decisions and how their choices would align with a National Comprehensive Cancer Network (NCCN) compliant, risk-directed management plan for high-risk cutaneous squamous cell carcinoma (cSCC).Methods: Clinicians attending a national dermatology conference were presented with 40-GEP test validation data. They were asked to rate clinicopathological features and molecular test results to assess their opinion of how concerning each is to cSCC prognosis. When presented with vignettes describing patients with NCCN-defined high-risk features, clinicians were asked to select a treatment plan using pre-test (no 40-GEP results), then, post-test (40-GEP Class 1, 2A, or 2B results) methodology along with corresponding metastasis rates for each test group.Results: Risk factors deemed of highest concern for metastatic outcomes were a Class 2B 40-GEP result, perineural invasion, immunosuppression, invasion beyond subcutaneous fat, and tumor diameter >1 cm on the scalp. When presented with a 40-GEP result that indicated reduced risk of metastasis (Class 1), clinicians altered their treatment management plan accordingly. Specifically, there was significant reduction in the recommendations for sentinel lymph node biopsy, adjuvant radiation or chemotherapy, follow-up time, and nodal imaging. By comparison, when a 40-GEP result indicated an increased risk of metastasis (Class 2B), significant risk-appropriate increases in management intensity was observed for the aforementioned clinical decisions.Conclusion: Integration of 40-GEP results impacted management decisions in a significant and risk-appropriate manner for high-risk cSCC patient scenarios, while remaining aligned with national guidelines for patient management. [ABSTRACT FROM AUTHOR]

Although p120-catenin (p120) is crucial for E-cadherin function, ablation experiments in epithelial tissues from different organ systems reveal markedly different effects. Here, we examine for the first time the consequences of p120 knockout during mouse mammary gland development. An MMTV-Cre driver was used to target knockout to the epithelium at the onset of puberty p120 ablation was detected in approximately one-quarter of the nascent epithelium at the forth week post-partum. However, p120 null cells were essentially nonadherent, excluded from the process of terminal end bud (TEB) morphogenesis and lost altogether by week six. This elimination process caused a delay in TEB outgrowth, after which the gland developed normally from cells that had retained p120. Mechanistic studies in vitro indicate that TEB dysfunction is likely to stem from striking E-cadherin loss, failure of cell-cell adhesion and near total exclusion from the collective migration process. Our findings reveal an essential role for p120 in mammary morphogenesis. [ABSTRACT FROM AUTHOR]

Simple Summary: Many people with skin cancer will have their cancer come back. The 31-gene expression profile (31-GEP) test can help predict if a cancer has a low (Class 1) or high (Class 2) chance of returning. This study looked at 86 patients with early skin cancer to see how well the 31-GEP test predicted if their cancer would return. None of the patients with a Class 1 GEP result had their cancer return within 3 years, but one-fourth of patients with a Class 2 result did. This study showed that the 31-GEP test can help predict if a patient's skin cancer will return. Accurate risk prediction can help doctors make better treatment plans for patients with skin cancer. Background: Fifteen to forty percent of patients with localized cutaneous melanoma (CM) (stages I–II) will experience disease relapse. The 31-gene expression profile (31-GEP) uses gene expression data from the primary tumor in conjunction with clinicopathologic features to refine patient prognosis. The study's objective was to evaluate 31-GEP risk stratification for disease-free survival (DFS) in a previously published cohort with longer follow-up. Methods: Patients with stage IB–II CM (n = 86) were prospectively tested with the 31-GEP. Follow-up time increased from 2.2 to 3.9 years. Patient outcomes were compared using Kaplan-Meier and Cox regression analysis. Results: A Class 2B result was a significant predictor of 3-year DFS (hazard ratio (HR) 8.4, p = 0.008) in univariate analysis. The 31-GEP significantly stratified patients by risk of relapse (p = 0.005). A Class 2B result was associated with a lower 3-year DFS (75.0%) than a Class 1A result (100%). The 31-GEP had a high sensitivity (77.8%) and negative predictive value (95.0%). Conclusions: The 31-GEP is a significant predictor of disease relapse in patients with stage IB–II melanoma and accurately stratified patients by risk of relapse. [ABSTRACT FROM AUTHOR]

We report here the effects of targeted p120-catenin (encoded by CTNND1; hereafter denoted p120) knockout (KO) in a PyMT mouse model of invasive ductal (mammary) cancer (IDC). Mosaic p120 ablation had little effect on primary tumor growth but caused significant pro-metastatic alterations in the tumor microenvironment, ultimately leading to a marked increase in the number and size of pulmonary metastases. Surprisingly, although early effects of p120-ablation included decreased cell–cell adhesion and increased invasiveness, cells lacking p120 were almost entirely unable to colonized distant metastatic sites in vivo. The relevance of this observation to human IDC was established by analysis of a large clinical dataset of 1126 IDCs. As reported by others, p120 downregulation in primary IDC predicted worse overall survival. However, as in the mice, distant metastases were almost invariably p120 positive, even in matched cases where the primary tumors were p120 negative. Collectively, our results demonstrate a strong positive role for p120 (and presumably E-cadherin) during metastatic colonization of distant sites. On the other hand, downregulation of p120 in the primary tumor enhanced metastatic dissemination indirectly via pro-metastatic conditioning of the tumor microenvironment. [ABSTRACT FROM AUTHOR]

Upregulation of MYC is a hallmark of cancer, wherein MYC drives oncogenic gene expression and elevates total RNA synthesis across cancer cell transcriptomes. Although this transcriptional anabolism fuels cancer growth and survival, the consequences and metabolic stresses induced by excess cellular RNA are poorly understood. Herein, we discover that RNA degradation and downstream ribonucleotide catabolism is a novel mechanism of MYC-induced cancer cell death. Combining genetics and metabolomics, we find that MYC increases RNA decay through the cytoplasmic exosome, resulting in the accumulation of cytotoxic RNA catabolites and reactive oxygen species. Notably, tumor-derived exosome mutations abrogate MYC-induced cell death, suggesting excess RNA decay may be toxic to human cancers. In agreement, purine salvage acts as a compensatory pathway that mitigates MYC-induced ribonucleotide catabolism, and inhibitors of purine salvage impair MYC+ tumor progression. Together, these data suggest that MYC-induced RNA decay is an oncogenic stress that can be exploited therapeutically. Significance: MYC is the most common oncogenic driver of poor-prognosis cancers but has been recalcitrant to therapeutic inhibition. We discovered a new vulnerability in MYC+ cancer where MYC induces cell death through excess RNA decay. Therapeutics that exacerbate downstream ribonucleotide catabolism provide a therapeutically tractable approach to TNBC (Triple-negative Breast Cancer) and other MYC-driven cancers., (©2024 The Authors; Published by the American Association for Cancer Research.)

The transforming growth factor-beta (TGF-beta) superfamily of growth factors is responsible for a variety of physiologic actions, including cell cycle regulation. Activin is a member of the TGF-beta superfamily that inhibits the proliferation of breast cancer cells. Activin functions by interacting with its type I and type II receptors to induce phosphorylation of intracellular signaling molecules known as Smads. Smads regulate transcription of many genes in a cell- and tissue-specific manner. In this study, the role of activin A in growth regulation of breast cancer cells was investigated. Activin stimulated the Smad-responsive promoter, p3TP, 2-fold over control in T47D breast cancer cells. Activin inhibited cellular proliferation of T47D breast cancer cells after 72 hours, an effect that could be abrogated by incubation with the activin type I receptor inhibitor, SB431542. Activin arrested T47D cells in the G0-G1 cell cycle phase. Smad2 and Smad3 were phosphorylated in response to activin and accumulated in the nucleus of treated T47D cells. Infection of T47D cells with adenoviral Smad3 resulted in cell cycle arrest and activation of p3TP-luciferase, whereas a adenoviral dominant-negative Smad3 blocked activin-mediated cell cycle arrest and gene transcription. Activin maintained expression of p21 and p27 cyclin-dependent kinase inhibitors involved in cell cycle control, enhanced expression of p15, reduced cyclin A expression, and reduced phosphorylation of the retinoblastoma (Rb) protein. Smad3 overexpression recapitulated activin-induced p15 expression and repression of cyclin A and Rb phosphorylation. These data indicate that activin A inhibits breast cancer cellular proliferation and activates Smads responsible for initiating cell cycle arrest.