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Background. Most ER+ tumors will eventually escape endocrine treatments. PI3K/mTOR pathway targeting has improved clinical results in endocrine treatments resistant (ETR) patients, however with unsustained responses. Our laboratory has developed several models of ETR luminal breast cancer (LBC) patient derived xenografts (PDX) suitable for biological studies (Cottu etal, AACR 2012 & IMPAKT 2012). The aims of the present study were 1) to analyze the biological factors associated with acquired ETR in relevant models of LBC; 2) to determine the therapeutic interest of combining everolimus with different ET models resistant to different endocrine treatments (ET). Methods. Implementation of LBC models has been reported (Cottu et al, BCRT 2012). ETR models were derived by selecting tumors growing under continuous ET, subsequently re-engrafted and rechallenged with endocrine therapies (tamoxifen, letrozole, fulvestrant), and with everolimus alone and combined with ETs. When possible, initial sensitive tumors were simultaneously treated with the same protocols. At progression, or after at least 120 days of continuous therapies, tumor tissue was retrieved. Tissue microarrays (TMA) were performed to analyze the biological modifications associated to ET and mTOR targeting. Triplicate immunohistochemistry of P-AKT/AKT, P-mTOR/mTOR and P-S6 were performed in addition to standard markers. Transcriptomic and RTPCR analyses are also being conducted. Results. Three models resistant to tamoxifen and 2 models resistant to surgical ovariectomy used a surrogate to estrogen deprivation, were developed from 3 initial PDX, and were maintained as independent hormone-resistant variants. All these models retained a luminal phenotype, based on IHC and transcriptomic analyses and had a wt PI3KCA. ETR models had an expression profile very similar to the initial PDX, suggesting that minor changes may be associated with the acquisition of an ETR phenotype. Three of these models have been tested. One tamoxifen resistant model confirmed a resistance specific to tamoxifen only and a high level of sensitivity to a fulvestrant everolimus combination. A second PDX yielded 2 other models resistant to tamoxifen and ovariectomy. These 2 models developed a resistance to all ET modalities. Therapeutic testing with combinations of everolimus and ETs were highly efficient, but everolimus alone was as efficient in these 2 models with complete and durable responses. Activation of the PI3K pathway was demonstrated in all cases by IHC analyses (expression of pAKT and pS6), and complementary ongoing RTPCR analyses. Everolimus based effects were associated with tumor fibrosis, a strong inhibition of Ki67 and pS6, but not always pAKT. The expression of ER was not modified by treatments, except in the fulvestrant-treated mice where it was strongly inhibited. Conclusion. We have developed and validated a platform of ETR models derived from our LBC original PDX. These models retained a luminal phenotype although highly resistant to ET. Activation of the PI3K pathway has been confirmed in ETR models, and everolimus alone, or combined with ET confirms high and durable efficacy. Updated mechanistic analyses performed at different time points will be presented at the meeting. [ABSTRACT FROM AUTHOR]

The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway is frequently hyperactivated in triple-negative breast cancers (TNBCs) associated with poor prognosis and is a therapeutic target in breast cancer management. Here, we describe the effects of repression of mTOR-containing complex 1 (mTORC1) through knockdown of several key mTORC1 components or with mTOR inhibitors used in cancer therapy. mTORC1 repression results in an ∼10-fold increase in extracellular matrix proteolytic degradation. Repression in several TNBC models, including in patient-derived xenografts (PDXs), induces nuclear translocation of transcription factor EB (TFEB), which drives a transcriptional program that controls endolysosome function and exocytosis. This response triggers a surge in endolysosomal recycling and the surface exposure of membrane type 1 matrix metalloproteinase (MT1-MMP) associated with invadopodia hyperfunctionality. Furthermore, repression of mTORC1 results in a basal-like breast cancer cell phenotype and disruption of ductal carcinoma in situ (DCIS)-like organization in a tumor xenograft model. Altogether, our data call for revaluation of mTOR inhibitors in breast cancer therapy., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Combination chemotherapy remains essential for clinical management of triple-negative breast cancer (TNBC). Consequently, responses to individual agents cannot be easily delineated at the single patient level, even though some patients might not require all drugs in the combination. Herein, we conduct multi-omic analyses of orthotopic TNBC patient-derived xenografts (PDXs) treated with single agent carboplatin, docetaxel, or the combination. Combination responses were usually no better than the best single agent, with enhanced response in only ~13% of PDX, and apparent antagonism in a comparable percentage. Single-omic comparisons showed largely non-overlapping results between genes associated with single agent and combination treatments that could be validated in independent patient cohorts. Multi-omic analyses of PDXs identified agent-specific biomarkers/biomarker combinations, nominating high Cytokeratin-5 (KRT5) as a general marker of responsiveness. Notably, integrating proteomic with transcriptomic data improved predictive modeling of pathologic complete response to combination chemotherapy. PDXs refractory to all treatments were enriched for signatures of dysregulated mitochondrial function. Targeting this process indirectly in a PDX with HDAC inhibition plus chemotherapy in vivo overcomes chemoresistance. These results suggest possible resistance mechanisms and therapeutic strategies in TNBC to overcome chemoresistance, and potentially allow optimization of chemotherapeutic regimens., Competing Interests: Declaration of Interests M.T.L is a Founder of, and an uncompensated Limited Partner in, StemMed Ltd., and an uncompensated Manager in StemMed Holdings L.L.C., its General Partner. M.T.L. is also a Founder of, and equity stake holder in, Tvardi Therapeutics Inc.. L.E.D. is a compensated employee of StemMed Ltd. Selected BCM PDX models described herein are exclusively licensed to StemMed Ltd. resulting in tangible property royalties to M.T.L. and L.E.D. Washington University in St. Louis has licensed selected PDX to Envigo which results in tangible property royalties to S.L. He also received research funding from Pfizer, Takeda Oncology, Zenopharm, independent of this project. S.L has received license fees from Envigo and also received research funding from Pfizer, Takeda Oncology, Zenopharm, outside of this project. M.J.E. is founder of Progendis, Inc and received consulting fees from Abbvie, Sermonix, Pfizer, AstraZeneca, Celgene, NanoString, Puma, Veracyte, Eli Lilly and Novartis, and is an equity stockholder and Board Director member of BioClassifier. M.J.E. is an inventor on a patent for the Breast Cancer PAM50-based assay, Prosigna, which is marketed by Veracyte. M.J.E. also receives royalties from Washington University in St. Louis when the WHIM PDX models are licensed to for-profit companies. M.F.R. received consulting fees from Pfizer, Novartis, AstraZeneca, and Gilead. C.K.O. is a stockholder of GeneTex. S.D. received consulting free from Taiho Oncology. F.M-B has advisory roles in Black Diamond, Biovica, Eisai, FogPharma, Immunomedics, Inflection Biosciences, Karyopharm Therapeutics, Loxo Oncology, Mersana Therapeutics, OnCusp Therapeutics, Puma Biotechnology Inc., Seattle Genetics, Sanofi, Silverback Therapeutics, Spectrum Pharmaceuticals, Zentalis; and received consulting fee from AbbVie, Aduro BioTech, Alkermes, AstraZeneca, Daiichi Sankyo, DebioPharm, Ecor1 Capital, eFFECTOR Therapeutics, F. Hoffman-La Roche, GT Apeiron, Genentech, Harbinger Health, IBM Watson, Infinity Pharmaceuticals, Jackson Laboratory, Kolon Life Science, Lengo Therapeutics, Menarini Group, OrigiMed, PACT Pharma, Parexel International, Pfizer, Protai Bio, Samsung Bioepis, Seattle Genetics, Tallac Therapeutics, Tyra Biosciences, Xencor, Zymeworks, European Organization for Research and Treatment of Cancer (EORTC), European Society for Medical Oncology (ESMO). B.Z. received consulting fee from AstraZeneca. G.V.E. receives sponsored research funding from Chimerix, Inc, and experimental research compounds from Chimerix, Inc and the Lead Discovery Center of Germany. M.A. received research funding from AstraZeneca. University of Utah may license the HCI PDX models described herein to for-profit companies, which may result in tangible property royalties to A.L.W. and/or B.E.W. A.L.W. has received research funding from AbbVie. All other authors have nothing to disclose.

Background: The literature lacks conclusive evidence regarding whether palliative care training confers a protective or predisposing influence on compassion fatigue. The present study hypothesizes that training in palliative care is associated with minor compassion fatigue levels among physicians and an improvement in their confidence in several procedures., Aim: To explore the physicians experiences with and without palliative care training who work as general practitioners in order to assess the prevalence of compassion fatigue in these groups., Methods: This is a quantitative and qualitative cross-sectional survey. For data analysis, Mann-Whitney and Pearson's chi-squared test tests were used considering P < 0.05 for significance., Results: The majority respondents had no training in palliative care (77.8%), however, 58.3% declared that they cared for at least 1 palliative care patient every 2 shifts - an intermediate frequency in our analysis. Trauma levels among doctors were classified as medium (24 ± 6), burnout as low (19 ± 5) and compassion as medium (41 ± 5). Professionals without training in palliative care had higher rates of burnout ( P = 0.002), but there was no association between training and rates of trauma or compassion., Conclusions: Doctors with training in palliative care in Brazil showed lower burnout rates when working as general practitioners in secondary hospitals. This could instigate the implementation of educational programs in palliative care at hospitals and the further development of the field so as to improve professionals' performance at patients' treatment. There was no difference between Trauma and Compassion scores., Competing Interests: Declaration of Conflicting InterestThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Endocrine therapy (ET) combined with cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) is the preferred first-line treatment for hormone receptor-positive (HR+)/HER2- metastatic breast cancer. Although this is beneficial, acquired resistance leads to disease progression, and patients harboring PIK3CA mutations are treated with targeted therapies such as the PI3Kα inhibitor, alpelisib, alongside ET. Drug-associated resistance mechanisms limit the efficacy of alpelisib, highlighting the need for better combination therapies. This study aimed to evaluate the efficacy of combining alpelisib with a highly specific PLK1 inhibitor, onvansertib, in PIK3CA -mutant HR+ breast cancer preclinical models., Methods: We assessed the effect of the alpelisib and onvansertib combination on cell viability, PI3K signaling pathway, cell cycle phase distribution and apoptosis in PI3K-activated HR+ breast cancer cell lines. The antitumor activity of the combination was evaluated in three PIK3CA -mutant HR+ breast cancer patient-derived xenograft (PDX) models, resistant to ET and CDK4/6 inhibitor palbociclib. Pharmacodynamics studies were performed using immunohistochemistry and Simple Western analyses in tumor tissues., Results: The combination synergistically inhibited cell viability, suppressed PI3K signaling, induced G2/M arrest and apoptosis in PI3K-activated cell lines. In the three PDX models, the combination demonstrated superior anti-tumor activity compared to the single agents. Pharmacodynamic studies confirmed the inhibition of both PLK1 and PI3K activity and pronounced apoptosis in the combination-treated tumors., Conclusions: Our findings support that targeting PLK1 and PI3Kα with onvansertib and alpelisib, respectively, may be a promising strategy for patients with PIK3CA -mutant HR+ breast cancer failing ET + CDK4/6i therapies and warrant clinical evaluation.

The European Society for Radiotherapy and Oncology (ESTRO) has advocated the establishment of guidelines to optimise precision radiotherapy (RT) in conjunction with contemporary therapeutics for cancer care. Quality assurance in RT (QART) plays a pivotal role in influencing treatment outcomes. Clinical trials incorporating QART protocols have demonstrated improved survival rates with minimal associated toxicity. Nonetheless, in routine clinical practice, there can be variability in the indications for RT, dosage, fractionation, and treatment planning, leading to uncertainty. In pivotal trials reporting outcomes of systemic therapy for breast cancer, there is limited information available regarding RT, and the potential interaction between modern systemic therapy and RT remains largely uncharted. This article is grounded in a consensus recommendation endorsed by ESTRO, formulated by international breast cancer experts. The consensus was reached through a modified Delphi process and was presented at an international meeting convened in Florence, Italy, in June 2023. These recommendations are regarded as both optimal and essential standards, with the latter aiming to define the minimum requirements. A template for a case report form (CRF) has been devised, which can be utilised by all clinical breast cancer trials involving RT. Optimal requirements include adherence to predefined RT planning protocols and centralised QART. Essential requirements aim to reduce variations and deviations from the guidelines in RT, even when RT is not the primary focus of the trial. These recommendations underscore the significance of implementing these practices in both clinical trials and daily clinical routines to generate high-quality data., Competing Interests: Declaration of competing interest IMe declares advisory boards supported by Eli Lilly, Novartis, Pfizer, Pierre Fabre, SeaGen, Daiichi Sankyo, Astra Zeneca. CB declares honoraria supported by declares advisory boards supported by Eli Lilly, Novartis, Pfizer, and Amgen. ML received honoraria and/or participated in advisory board from Roche, Novartis, Lilly, Pfizer, AstraZeneca, Daiichi Sankyo, Gilead, SeaGen, MSD, Exact Sciences, Takeda, Ipsen, Sandoz, Libbs & Knight, a travel grant from Gilead and research support to the Institution from Gilead. EdA disclosed honoraria and/or advisory board from Roche/GNE, Novartis, SeaGen, Zodiac, Libbs, Pierre Fabre, Lilly, AstraZeneca. JC disclosed consulting/advisor for Roche, Celgene, Cellestia, AstraZeneca, SeaGen, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck Sharp & Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, Reveal Genomics, Expres2ion Biotechnologies. NH disclosed honoraria for lectures and/or consulting from AstraZeneca, Daiichi-Sankyo, Gilead, Lilly, MSD, Novartis, Pierre-Fabre, Pfizer, Roche, Sanofi, Sandoz, SeaGen. HSR disclosed institutional research support by Astellas Pharma Inc., AstraZeneca, Daiichi Sankyo Inc., F. Hoffmann-La Roche AG/Genentech, Inc., Gilead Sciences Inc., GlaxoSmithKline, Lilly, Merck & Co. Inc., Novartis Pharmaceuticals Corporation, OBI Pharma, Pfizer, Pionyr Immunotherapeutics, Sermonix Pharmaceuticals Inc., Taiho Oncology Inc., and Veru Inc. GC reports personal fees for consulting, advisory role and speakers’ bureau from Roche/Genentech, Novartis, Pfizer, Lilly, Foundation Medicine, Samsung and Daiichi Sankyo; honoraria from Ellipses Pharma and fees for travel and accommodations from Roche/Genentech and Pfizer. LV declares participation on advisory board from Daiichi Sankyo and Pfizer. ME declares advisory board supported by Pfizer and Novartis and lecture fees supported by AstraZeneca. GM declares consultancy honoraria from Roche, Novartis, AstraZeneca, Pfizer, Jensen, Lilly, and Sanofi. LDM declares consulting fees from Roche, Novartis, Eli Lilly, MSD, Daiichi Sankyo, SeaGen, Gilead, Eisai, Pierre Fabre, AstraZeneca, Stemline Menarini, Exact Sciences, Agendia, GSK, Pfizer. No other competing interests declared., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Aims: Human epidermal growth factor receptor 2 (HER2) is an oncogenic receptor tyrosine kinase amplified in approximately 20% of breast cancer (BC). HER2-targeted therapies are the linchpin of treating HER2-positive BC. However, drug resistance is common, and the main resistance mechanism is unknown. We tested the hypothesis that drug resistance results mainly from inadequate or lack of inhibition of HER2 and its family member epidermal growth factor receptor (EGFR)., Methods: We used clinically relevant cell and tumor models to assess the impact of targeted degradation of HER2 and EGFR on trastuzumab resistance. Trastuzumab is the most common clinically used HER2 inhibitor. Targeted degradation of HER2 and EGFR was achieved using recombinant human protein PEPD G278D , which binds to the extracellular domains of the receptors. siRNA knockdown was used to assess the relative importance of EGFR and HER2 in trastuzumab resistance., Results: Both HER2 and EGFR are overexpressed in all trastuzumab-resistant HER2-positive BC cell and tumor models and that all trastuzumab-resistant models are highly vulnerable to targeted degradation of HER2 and EGFR. Degradation of HER2 and EGFR induced by PEPD G278D causes extensive inhibition of oncogenic signaling in trastuzumab-resistant HER2-positive BC cells. This is accompanied by strong growth inhibition of cultured cells, orthotopic patient-derived xenografts, and metastatic lesions in the brain and lung of trastuzumab-resistant HER2-positive BC. siRNA knockdown indicates that eliminating both HER2 and EGFR is necessary to maximize therapeutic outcome., Conclusions: This study unravels the therapeutic vulnerability of trastuzumab-resistant HER2-positive BC and shows that an agent that targets the degradation of both HER2 and EGFR is highly effective in overcoming drug resistance in this disease. The findings provide new insights and innovations for advancing treatment of drug-resistant HER2-positive breast cancer that remains an unmet problem., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Targeting aromatase deprives ER + breast cancers of estrogens and is an effective therapeutic approach for these tumors. However, drug resistance is an unmet clinical need. Lipidomic analysis of long-term estrogen-deprived (LTED) ER + breast cancer cells, a model of aromatase inhibitor resistance, revealed enhanced intracellular lipid storage. Functional metabolic analysis showed that lipid droplets together with peroxisomes, which we showed to be enriched and active in the LTED cells, controlled redox homeostasis and conferred metabolic adaptability to the resistant tumors. This reprogramming was controlled by acetyl-CoA-carboxylase-1 (ACC1), whose targeting selectively impaired LTED survival. However, the addition of branched- and very long-chain fatty acids reverted ACC1 inhibition, a process that was mediated by peroxisome function and redox homeostasis. The therapeutic relevance of these findings was validated in aromatase inhibitor-treated patient-derived samples. Last, targeting ACC1 reduced tumor growth of resistant patient-derived xenografts, thus identifying a targetable hub to combat the acquisition of estrogen independence in ER + breast cancers.

Novel systemic therapies for breast cancer are being rapidly implemented into clinical practice. These drugs often have different mechanisms of action and side-effect profiles compared with traditional chemotherapy. Underpinning practice-changing clinical trials focused on the systemic therapies under investigation, thus there are sparse data available on radiotherapy. Integration of these new systemic therapies with radiotherapy is therefore challenging. Given this rapid, transformative change in breast cancer multimodal management, the multidisciplinary community must unite to ensure optimal, safe, and equitable treatment for all patients. The aim of this collaborative group of radiation, clinical, and medical oncologists, basic and translational scientists, and patient advocates was to: scope, synthesise, and summarise the literature on integrating novel drugs with radiotherapy for breast cancer; produce consensus statements on drug-radiotherapy integration, where specific evidence is lacking; and make best-practice recommendations for recording of radiotherapy data and quality assurance for subsequent studies testing novel drugs., Competing Interests: Declaration of interests IMe declares participation in advisory boards supported by Eli Lilly, Novartis, Pfizer, Pierre Fabre, SeaGen, Daiichi Sankyo, and AstraZeneca. CB declares honoraria from Eli Lilly, and participation in advisory boards supported by Eli Lilly, Novartis, Pfizer, and Amgen. ML received honoraria from or participated in advisory boards for Roche, Novartis, Eli Lilly, Pfizer, AstraZeneca, Daiichi Sankyo, Gilead, SeaGen, Merck Sharp and Dohme, Exact Sciences, Takeda, Ipsen, Sandoz, Libbs, and Knight; received a travel grant from Gilead; and received research support for their institution from Gilead. EdA declares honoraria from or participation in advisory boards for Roche, Genentech, Novartis, SeaGen, Zodiac, Libbs, Pierre Fabre, Eli Lilly, and AstraZeneca. JC declares consulting or advisor roles supported by Roche, Celgene, Cellestia, AstraZeneca, SeaGen, Daiichi Sankyo, Erytech, Athenex, Polyphor, Eli Lilly, Merck Sharp and Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, Reveal Genomics, and Expres2ion Biotechnologies. NH declares honoraria for lectures or consulting from AstraZeneca, Daiichi Sankyo, Gilead, Eli Lilly, Merck Sharp and Dohme, Novartis, Pierre Fabre, Pfizer, Roche, Sanofi, Sandoz, and SeaGen. HSR declares institutional research support from Astellas Pharma, AstraZeneca, Daiichi Sankyo, F Hoffmann-La Roche, Genentech, Gilead Sciences, GSK, Eli Lilly, Merck & Co, Novartis Pharmaceuticals Corporation, OBI Pharma, Pfizer, Pionyr Immunotherapeutics, Sermonix Pharmaceuticals, Taiho Oncology, and Veru. GC reports personal fees for consulting, advisory roles, and speakers’ bureau from Roche, Genentech, Novartis, Pfizer, Eli Lilly, Foundation Medicine, Samsung, and Daiichi Sankyo; honoraria from Ellipses Pharma; and fees for travel and accommodations from Roche, Genentech, and Pfizer. LV declares participation in advisory boards from Daiichi Sankyo and Pfizer. ME declares participation in advisory boards supported by Pfizer and Novartis, and lecture fees supported by AstraZeneca. TS declares participation in advisory boards supported by Bristol Myers Squibb, Merck Sharp and Dohme, Novartis, and Pierre Fabre; and lecture fees supported by Astellas, AstraZeneca, and Bristol Myers Squibb. GM declares consultancy honoraria from Roche, Novartis, AstraZeneca, Pfizer, Jensen, Eli Lilly, and Sanofi. LDM declares consulting fees from Roche, Novartis, Eli Lilly, Merck Sharp and Dohme, Daiichi Sankyo, SeaGen, Gilead, Eisai, Pierre Fabre, AstraZeneca, Stemline Menarini, Exact Sciences, Agendia, GSK, and Pfizer. MM declares consulting fees from Cedilla Therapeutics and PharmEnable, and research support from PharmaMar, Eli Lilly, Pfizer, and Circle Pharma. SP-S declares consulting fees from Pfizer, Novartis, Eli Lilly, AstraZeneca, Gilead, Merck, Sharp and Dohme, and Roche. BP declares consulting fees from Astra Zeneca, SeaGen, Gilead, Eli Lilly, Merck Sharp and Dohme, Daiichi Sankyo, and Pierre Fabre. CS declares consulting fees from AstraZeneca, Daiichi Sankyo, Eisai Europe, Gilead, Novartis, Pharmalex, Pfizer, Phillips Health Works, Pierre Fabre, PintPharma, Puma Biotechnology, Roche Farma, SeaGen, Solti, Synthon Biopharmaceuticals, and Zymeworks. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The combination of endocrine therapy and CDK4/6 inhibitors such as palbociclib is an effective and well-tolerated treatment for estrogen receptor-positive (ER+) breast cancer, yet many patients relapse with therapy-resistant disease. Determining the mechanisms underlying endocrine therapy resistance is limited by the lack of ability to fully recapitulate inter- and intratumor heterogeneity in vitro and of availability of tumor samples from women with disease progression or relapse. In this study, multiple cell line models of resistant disease were used for both two-dimensional (2D)- and three-dimensional (3D)-based inhibitor screening. The screens confirmed the previously reported role of pro-proliferative pathways, such as PI3K-AKT-mTOR, in endocrine therapy resistance and additionally identified the transcription-associated cyclin-dependent kinase CDK9 as a common hit in ER+ cell lines and patient-derived organoids modeling endocrine therapy-resistant disease in both the palbociclib-sensitive and palbociclib-resistant settings. The CDK9 inhibitor, AZD4573, currently in clinical trials for hematologic malignancies, acted synergistically with palbociclib in these ER+in vitro 2D and 3D models. In addition, in two independent endocrine- and palbociclib-resistance patient-derived xenografts, treatment with AZD4573 in combination with palbociclib and fulvestrant resulted in tumor regression. Tumor transcriptional profiling identified a set of transcriptional and cell-cycle regulators differentially downregulated only in combination-treated tumors. Together, these findings identify a clinically tractable combination strategy for overcoming resistance to endocrine therapy and CDK4/6 inhibitors in breast cancer and provide insight into the potential mechanism of drug efficacy in targeting treatment-resistant disease., Significance: Targeting transcription-associated CDK9 synergizes with CDK4/6 inhibitor to drive tumor regression in multiple models of endocrine- and palbociclib-resistant ER+ breast cancer, which could address the challenge of overcoming resistance in patients., (©2023 The Authors; Published by the American Association for Cancer Research.)

Oral selective estrogen receptor degraders (SERD) could become the backbone of endocrine therapy (ET) for estrogen receptor-positive (ER+) breast cancer, as they achieve greater inhibition of ER-driven cancers than current ETs and overcome key resistance mechanisms. In this study, we evaluated the preclinical pharmacology and efficacy of the next-generation oral SERD camizestrant (AZD9833) and assessed ER-co-targeting strategies by combining camizestrant with CDK4/6 inhibitors (CDK4/6i) and PI3K/AKT/mTOR-targeted therapy in models of progression on CDK4/6i and/or ET. Camizestrant demonstrated robust and selective ER degradation, modulated ER-regulated gene expression, and induced complete ER antagonism and significant antiproliferation activity in ESR1 wild-type (ESR1wt) and mutant (ESR1m) breast cancer cell lines and patient-derived xenograft (PDX) models. Camizestrant also delivered strong antitumor activity in fulvestrant-resistant ESR1wt and ESR1m PDX models. Evaluation of camizestrant in combination with CDK4/6i (palbociclib or abemaciclib) in CDK4/6-naive and -resistant models, as well as in combination with PI3Kαi (alpelisib), mTORi (everolimus), or AKTi (capivasertib), indicated that camizestrant was active with CDK4/6i or PI3K/AKT/mTORi and that antitumor activity was further increased by the triple combination. The response was observed independently of PI3K pathway mutation status. Overall, camizestrant shows strong and broad antitumor activity in ER+ breast cancer as a monotherapy and when combined with CDK4/6i and PI3K/AKT/mTORi., Significance: Camizestrant, a next-generation oral SERD, shows promise in preclinical models of ER+ breast cancer alone and in combination with CDK4/6 and PI3K/AKT/mTOR inhibitors to address endocrine resistance, a current barrier to treatment., (©2023 The Authors; Published by the American Association for Cancer Research.)

(1) Background: Acute kidney injury (AKI) is common among critically ill COVID-19 patients, but its temporal association with prone positioning (PP) is still unknown, and no data exist on the possibility of predicting PP-associated AKI from bedside clinical variables. (2) Methods: We analyzed data from 93 COVID-19-related ARDS patients who underwent invasive mechanical ventilation (IMV) and at least one PP cycle. We collected hemodynamic variables, respiratory mechanics, and circulating biomarkers before, during, and after the first PP cycle. PP-associated AKI (PP-AKI) was defined as AKI diagnosed any time from the start of PP to 48 h after returning to the supine position. A t -test for independent samples was used to test for the differences between groups, while binomial logistical regression was performed to assess variables independently associated with PP-associated AKI. (3) Results: A total of 48/93 (52%) patients developed PP-AKI, with a median onset at 24 [13.5-44.5] hours after starting PP. No significant differences in demographic characteristics between groups were found. Before starting the first PP cycle, patients who developed PP-AKI had a significantly lower cumulative fluid balance (CFB), even when normalized for body weight ( p = 0.006). Central venous pressure (CVP) values, measured before the first PP (OR 0.803, 95% CI [0.684-0.942], p = 0.007), as well as BMI (OR 1.153, 95% CI = [1.013-1.313], p = 0.031), were independently associated with the development of PP-AKI. In the multivariable regression analysis, a lower CVP before the first PP cycle was independently associated with ventilator-free days (OR 0.271, 95% CI [0.123-0.936], p = 0.011) and with ICU mortality (OR:0.831, 95% CI [0.699-0.989], p = 0.037). (4) Conclusions: Acute kidney injury occurs frequently in invasively ventilated severe COVID-19 ARDS patients undergoing their first prone positioning cycle. Higher BMI and lower CVP before PP are independently associated with the occurrence of AKI during prone positioning.

Resistance to endocrine therapy and CDK4/6 inhibitors, the standard of care (SOC) in estrogen receptor-positive (ER+) breast cancer, greatly reduces patient survival. Therefore, elucidating the mechanisms of sensitivity and resistance to SOC therapy and identifying actionable targets are urgently needed. Here, we show that SOC therapy causes DNA damage and toxic PARP1 trapping upon generation of a functional BRCAness (i.e., BRCA1/2 deficiency) phenotype, leading to increased histone parylation and reduced H3K9 acetylation, resulting in transcriptional blockage and cell death. Mechanistically, SOC therapy downregulates phosphodiesterase 4D (PDE4D), a novel ER target gene in a feedforward loop with ER, resulting in increased cAMP, PKA-dependent phosphorylation of mitochondrial COXIV-I, ROS generation and DNA damage. However, during SOC resistance, an ER-to-EGFR switch induces PDE4D overexpression via c-Jun. Notably, combining SOC with inhibitors of PDE4D, EGFR or PARP1 overcomes SOC resistance irrespective of the BRCA1/2 status, providing actionable targets for restoring SOC efficacy., (© 2023. The Author(s).)

Liver X receptors (LXRs) are nuclear transcription factors important in the regulation of cholesterol transport, and glucose and fatty acid metabolism. The antiproliferative role of LXRs has been studied in a variety of malignancies and may represent a therapeutic opportunity in cancers lacking targeted therapies, such as triple-negative breast cancer. In this study, we investigated the impact of LXR agonists alone and in combination with carboplatin in preclinical models of breast cancer. In vitro experiments revealed a dose-dependent decrease in tumor cell proliferation in estrogen receptor-positive breast cancer cells, whereas LXR activation in vivo resulted in an increased growth inhibitory effect in a basal-like breast cancer model (in combination with carboplatin). Functional proteomic analysis identified differences in protein expression between responding and nonresponding models related to Akt activity, cell-cycle progression, and DNA repair. Furthermore, pathway analysis suggested that the LXR agonist in combination with carboplatin inhibits the activity of targets of E2F transcription factors and affects cholesterol homeostasis in basal-like breast cancer., (© 2023 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Drug resistance and cancer relapse represent significant therapeutic challenges after chemotherapy or immunotherapy, and a major limiting factor for long-term cancer survival. Netrin-1 was initially identified as a neuronal navigation cue but has more recently emerged as an interesting target for cancer therapy, which is currently clinically investigated. We show here that netrin-1 is an independent prognostic marker for clinical progression of breast and ovary cancers. Cancer stem cells (CSCs)/Tumor initiating cells (TICs) are hypothesized to be involved in clinical progression, tumor relapse and resistance. We found a significant correlation between netrin-1 expression and cancer stem cell (CSC) markers levels. We also show in different mice models of resistance to chemotherapies that netrin-1 interference using a therapeutic netrin-1 blocking antibody alleviates resistance to chemotherapy and triggers an efficient delay in tumor relapse and this effect is associated with CSCs loss. We also demonstrate that netrin-1 interference limits tumor resistance to immune checkpoint inhibitor and provide evidence linking this enhanced anti-tumor efficacy to a decreased recruitment of a subtype of myeloid-derived suppressor cells (MDSCs) called polymorphonuclear (PMN)-MDSCs. We have functionally demonstrated that these immune cells promote CSCs features and, consequently, resistance to anti-cancer treatments. Together, these data support the view of both a direct and indirect contribution of netrin-1 to cancer stemness and we propose that this may lead to therapeutic opportunities by combining conventional chemotherapies and immunotherapies with netrin-1 interfering drugs., (© 2023. The Author(s), under exclusive licence to ADMC Associazione Differenziamento e Morte Cellulare.)

Triple negative breast cancers (TNBCs) represent 15-20% of all breast cancers and are associated with higher recurrence and distant metastasis rate. Standard of care for early stage TNBC is anthracyclines combined with cyclophosphamide (AC) followed by taxanes, in the neo-adjuvant or adjuvant setting. This work aimed to identify predictive biomarkers of AC response in patient-derived xenograft (PDX) models of TNBC and to validate them in the clinical setting. By gene and protein expression analysis of 39 PDX with different responses to AC, we found that high expression of HORMAD1 was associated with better response to AC. Both gene and protein expression were associated with promoter hypomethylation. In a cohort of 526 breast cancer patients, HORMAD1 was overexpressed in 71% of TNBC. In a second cohort of 186 TNBC patients treated with AC, HORMAD1 expression was associated with longer metastasis-free survival (MFS). In summary, HORMAD1 overexpression was predictive of an improved response to AC in PDX and is an independent prognostic factor in TNBC patients treated with AC., (© 2023 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

The cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) have become the standard of care for hormone receptor-positive (HR + ) and human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer, improving survival outcomes compared to endocrine therapy alone. Abemaciclib and ribociclib, in combination with endocrine therapy, have demonstrated significant benefits in invasive disease-free survival for high-risk HR+/HER2- early breast cancer patients. Each CDK4/6i-palbociclib, ribociclib, and abemaciclib-exhibits distinct toxicity profiles. Radiation therapy (RT) can be delivered with a palliative or ablative intent, particularly using stereotactic body radiation therapy for oligometastatic or oligoprogressive disease. However, pivotal randomized trials lack information on concomitant CDK4/6i and RT, and existing preclinical and clinical data on the potential combined toxicities are limited and conflicting. As part of a broader effort to establish international consensus recommendations for integrating RT and targeted agents in breast cancer treatment, we conducted a systematic review and meta-analysis to evaluate the safety profile of combining CDK4/6i with palliative and ablative RT in both metastatic and early breast cancer settings., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background and Purpose: In recent years, the treatment landscape for breast cancer has undergone significant advancements, with the introduction of several new anticancer agents. One such agent is trastuzumab emtansine (T-DM1), an antibody drug conjugate that has shown improved outcomes in both early and advanced breast cancer. However, there is currently a lack of comprehensive evidence regarding the safety profile of combining T-DM1 with radiation therapy (RT). In this study, we aim to provide a summary of the available data on the safety of combining RT with T-DM1 in both early and metastatic breast cancer settings., Materials and Methods: This systematic review and meta-analysis project is part of the consensus recommendations by the European Society for Radiotherapy and Oncology (ESTRO) Guidelines Committee on integrating RT with targeted treatments for breast cancer. A thorough literature search was conducted using the PUBMED/MedLine, Embase, and Cochrane databases to identify original studies focusing on the safety profile of combining T-DM1 with RT., Results: After applying eligibility criteria, nine articles were included in the meta-analysis. Pooled data from these studies revealed a high incidence of grade 3 + radionecrosis (17%), while the rates of grade 3 + radiation-related pneumonitis (<1%) and skin toxicity (1%) were found to be very low., Conclusion: Although there is some concern regarding a slight increase in pneumonitis when combining T-DM1 with postoperative RT, the safety profile of this combination was deemed acceptable for locoregional treatment in non-metastatic breast cancer. However, caution is advised when irradiating intracranial sites concurrently with T-DM1. There is a pressing need for international consensus guidelines regarding the safety considerations of combining T-DM1 and RT for breast cancer., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Endocrine therapies targeting estrogen signaling, such as tamoxifen, have significantly improved management of estrogen receptor alpha (ERα)-positive breast cancers. However, their efficacy is limited by intrinsic and acquired resistance to treatment, and there is currently no predictive marker of response to these anti-estrogens to guide treatment decision. Here, using two independent cohorts of breast cancer patients, we identified nuclear PRMT5 expression as an independent predictive marker of sensitivity to tamoxifen. Mechanistically, we discovered that tamoxifen stimulates ERα methylation by PRMT5, a key event for its binding to corepressors such as SMRT and HDAC1, participating in the inhibition of the transcriptional activity of ERα. Although PRMT5 is mainly localized in the cytoplasm of tumor cells, our analyses show that tamoxifen triggers its nuclear translocation in tamoxifen-sensitive tumors but not in resistant ones. Hence, we unveil a biomarker of sensitivity to tamoxifen in ERα-positive breast tumors that could be used to enhance the response of breast cancer patients to endocrine therapy, by fostering its nuclear expression., (© 2023 The Authors. Published under the terms of the CC BY 4.0 license.)

Triple-negative breast cancers (TNBCs) are the most aggressive breast cancers, and therapeutic options mainly rely on chemotherapy and immunotherapy. Although synthetic glucocorticoids (GCs) are given to alleviate the side effects of these treatments, GCs and their receptor, the glucocorticoid receptor (GR), were recently associated with detrimental effects, albeit the mechanisms involved remain elusive. Here, we identified the arginine methyltransferase PRMT5 as a master coregulator of GR, serving as a scaffold protein to recruit phospho-HP1γ and subsequently RNA polymerase II, independently of its methyltransferase activity. Moreover, the GR/PRMT5/HP1γ complex regulated the transcription of GC-target genes involved in cell motility and triggering cell migration of human TNBC cells in vitro and in a zebrafish model. Of note, we observed that GR/PRMT5 interaction was low in primary tumors but significantly increased in residual tumors treated with chemotherapy and GCs in neoadjuvant setting. These data suggest that the routine premedication prescription of GCs for early TNBC patients should be further assessed and that this complex could potentially be modulated to specifically target deleterious GR effects., (© 2023 Noureddine et al.)

Resistance to endocrine treatments and CDK4/6 inhibitors is considered a near-inevitability in most patients with estrogen receptor positive breast cancers (ER + BC). By genomic and metabolomics analyses of patients' tumours, metastasis-derived patient-derived xenografts (PDX) and isogenic cell lines we demonstrate that a fraction of metastatic ER + BC is highly reliant on oxidative phosphorylation (OXPHOS). Treatment by the OXPHOS inhibitor IACS-010759 strongly inhibits tumour growth in multiple endocrine and palbociclib resistant PDX. Mutations in the PIK3CA/AKT1 genes are significantly associated with response to IACS-010759. At the metabolic level, in vivo response to IACS-010759 is associated with decreased levels of metabolites of the glutathione, glycogen and pentose phosphate pathways in treated tumours. In vitro, endocrine and palbociclib resistant cells show increased OXPHOS dependency and increased ROS levels upon IACS-010759 treatment. Finally, in ER + BC patients, high expression of OXPHOS associated genes predict poor prognosis. In conclusion, these results identify OXPHOS as a promising target for treatment resistant ER + BC patients., (© 2023. The Author(s).)

The high frequency of homologous recombination deficiency (HRD) is the main rationale of testing platinum-based chemotherapy in triple-negative breast cancer (TNBC), however, the existing methods to identify HRD are controversial and there is a medical need for predictive biomarkers. We assess the in vivo response to platinum agents in 55 patient-derived xenografts (PDX) of TNBC to identify determinants of response. The HRD status, determined from whole genome sequencing, is highly predictive of platinum response. BRCA1 promoter methylation is not associated with response, in part due to residual BRCA1 gene expression and homologous recombination proficiency in different tumours showing mono-allelic methylation. Finally, in 2 cisplatin sensitive tumours we identify mutations in XRCC3 and ORC1 genes that are functionally validated in vitro. In conclusion, our results demonstrate that the genomic HRD is predictive of platinum response in a large cohort of TNBC PDX and identify alterations in XRCC3 and ORC1 genes driving cisplatin response., (© 2023. The Author(s).)

Triple-negative breast cancer (TNBC) is a highly heterogeneous cancer lacking actionable targets. Using a phenotypic screen of TNBC cells, we discovered a novel multiple kinase inhibitor tinengotinib (TT-00420) that strongly inhibited Aurora A/B, FGFR1/2/3, VEGFRs, JAK1/2, and CSF1R in biochemical assays. Exposure to tinengotinib specifically inhibited proliferation across all subtypes of TNBC in vitro and in vivo, while leaving luminal breast cancer cells intact. Incubation of HCC1806 with tinengotinib led to dose-dependent downregulation of genes essential for TNBC cell growth and proliferation. Studies revealed that the potential mechanism of action of tinengotinib involved, predominantly, inhibition of Aurora A or B kinase activity, while inhibition of other pathways contributed to suppression of potency and activity. In vitro treatment of TNBC cell lines or in vivo administration in a syngeneic model with tinengotinib resulted in up-regulation of CXCL10 and 11 or diminished tumor-associated macrophage (TAM) infiltration. Tinengotinib represents a novel combinatorial inhibitory mechanism to treat TNBC. The phase I trial of tinengotinib was completed (ClinicalTrials.gov identifier: NCT03654547)., (©2022 The Authors; Published by the American Association for Cancer Research.)

The prevention of nicotinamide adenine dinucleotide (NAD) biosynthesis is considered an attractive therapeutic approach against cancer, considering that tumor cells are characterized by an increased need for NAD to fuel their reprogrammed metabolism. On the other hand, the decline of NAD is a hallmark of some pathological conditions, including neurodegeneration and metabolic diseases, and boosting NAD biosynthesis has proven to be of therapeutic relevance. Therefore, targeting the enzymes nicotinamide phosphoribosyltransferase (NAMPT) and nicotinate phosphoribosyltransferase (NAPRT), which regulate NAD biosynthesis from nicotinamide (NAM) and nicotinic acid (NA), respectively, is considered a promising strategy to modulate intracellular NAD pool. While potent NAMPT inhibitors and activators have been developed, the search for NAPRT modulators is still in its infancy. In this work, we report on the identification of a new class of NAPRT modulators bearing the 1,2-dimethylbenzimidazole scaffold properly substituted in position 5. In particular, compounds 24 , 31 , and 32 emerged as the first NAPRT activators reported so far, while 18 behaved as a noncompetitive inhibitor toward NA ( K i = 338 µM) and a mixed inhibitor toward phosphoribosyl pyrophosphate (PRPP) ( K i = 134 µM). From in vitro pharmacokinetic studies, compound 18 showed an overall good ADME profile. To rationalize the obtained results, docking studies were performed on the NAPRT structure. Moreover, a preliminary pharmacophore model was built to shed light on the shift from inhibitors to activators.

Early detection of cancer is critical in medical sciences, as the sooner a cancer is diagnosed, the higher are the chances of recovery. Tumour cells are characterized by specific volatile organic compounds (VOCs) that can be used as cancer biomarkers. Through olfactory associative learning, animals can be trained to detect these VOCs. Insects such as ants have a refined sense of smell, and can be easily and rapidly trained with olfactory conditioning. Using urine from patient-derived xenograft mice as stimulus, we demonstrate that individual ants can learn to discriminate the odour of healthy mice from that of tumour-bearing mice and do so after only three conditioning trials. After training, they spend approximately 20% more time in the vicinity of the learned odour than beside the other stimulus. Chemical analyses confirmed that the presence of the tumour changed the urine odour, supporting the behavioural results. Our study demonstrates that ants reliably detect tumour cues in mice urine and have the potential to act as efficient and inexpensive cancer bio-detectors.

The maintenance of a proper NAD + pool is essential for cell survival, and tumor cells are particularly sensitive to changes in coenzyme levels. In this view, the inhibition of NAD + biosynthesis is considered a promising therapeutic approach. Current research is mostly focused on targeting the enzymes nicotinamide phosphoribosyltransferase (NAMPT) and nicotinate phosphoribosyltransferase (NAPRT), which regulate NAD + biosynthesis from nicotinamide and nicotinic acid, respectively. In several types of cancer cells, both enzymes are relevant for NAD + biosynthesis, with NAPRT being responsible for cell resistance to NAMPT inhibition. While potent NAMPT inhibitors have been developed, only a few weak NAPRT inhibitors have been identified so far, essentially due to the lack of an easy and fast screening assay. Here we present a continuous coupled fluorometric assay whereby the product of the NAPRT-catalyzed reaction is enzymatically converted to NADH, and NADH formation is measured fluorometrically. The assay can be adapted to screen compounds that interfere with NADH excitation and emission wavelengths by coupling NADH formation to the cycling reduction of resazurin to resorufin, which is monitored at longer wavelengths. The assay system was validated by confirming the inhibitory effect of some NA-related compounds on purified human recombinant NAPRT. In particular, 2-hydroxynicotinic acid, 2-amminonicotinic acid, 2-fluoronicotinic acid, pyrazine-2-carboxylic acid, and salicylic acid were confirmed as NAPRT inhibitors, with Ki ranging from 149 to 348 µM. Both 2-hydroxynicotinic acid and pyrazine-2-carboxylic acid were found to sensitize OVCAR-5 cells to the NAMPT inhibitor FK866 by decreasing viability and intracellular NAD + levels.

Acute necrotizing encephalopathy (ANE) is a rare disease not yet described in children with Covid-19. RANBP2 gene variations are implicated in recurrences in the genetic form of ANE, the so called ANE1. We report the first case of pediatric ANE1 following Sars-CoV-2 infection. She had a first episode at 2 years of age following influenza type A with full recovery, many other respiratory and non-respiratory febrile viral infections without recurrences and a severe recurrence following Sars-CoV-2 infection, suggesting a potentiation effect on cytokine cascade. Her MRI showed the typical pattern of injury resembling that of mitochondrial disorders, and supported the role of RANBP2 in mitochondrial homeostasis. This case rises attention on diagnostic challenges and offers several interesting tips for discussion about new perspectives in pathogenesis and targeted treatments., Competing Interests: Declaration of competing interest The authors of the Manuscript “Pediatric recurrent acute necrotizing encephalomyelitis, RANBP2 genotype and Sars-CoV-2 infection: diagnosis, pathogenesis and targeted treatments from a case study” have no conflicts of interest to disclose., (© 2022 Published by Elsevier Ltd on behalf of European Paediatric Neurology Society.)

Although systemic chemotherapy remains the standard of care for TNBC, even combination chemotherapy is often ineffective. The identification of biomarkers for differential chemotherapy response would allow for the selection of responsive patients, thus maximizing efficacy and minimizing toxicities. Here, we leverage TNBC PDXs to identify biomarkers of response. To demonstrate their ability to function as a preclinical cohort, PDXs were characterized using DNA sequencing, transcriptomics, and proteomics to show consistency with clinical samples. We then developed a network-based approach (CTD/WGCNA) to identify biomarkers of response to carboplatin (MSI1, TMSB15A, ARHGDIB, GGT1, SV2A, SEC14L2, SERPINI1, ADAMTS20, DGKQ) and docetaxel (c, MAGED4, CERS1, ST8SIA2, KIF24, PARPBP). CTD/WGCNA multigene biomarkers are predictive in PDX datasets (RNAseq and Affymetrix) for both taxane- (docetaxel or paclitaxel) and platinum-based (carboplatin or cisplatin) response, thereby demonstrating cross-expression platform and cross-drug class robustness. These biomarkers were also predictive in clinical datasets, thus demonstrating translational potential., Competing Interests: M.T.L is a Founder of, and an uncompensated Limited Partner in, StemMed Ltd., and an uncompensated Manager in StemMed Holdings L.L.C., its General Partner. MTL is also a Founder of, and equity stake holder in, Tvardi Therapeutics Inc. L.E.D. is a compensated employee of StemMed Ltd. Selected BCM PDX models described herein are exclusively licensed to StemMed Ltd., resulting in tangible property royalties to M.T.L. and L.E.D. University of Utah may license the HCI PDX models described herein to for-profit companies, which may result in tangible property royalties to A.L.W. and B.E.W. Washington University has licensed selected PDX to Envigo, which results in tangible property royalties to S.L. He also received research funding from Pfizer, Takeda Oncology, and Zenopharm, independent of this project. S.L. has received license fees from Envigo. He received research funding from Pfizer, Takeda Oncology, and Zenopharm, outside of this project. O.S, is a compensated employee of, and equity stake holder in, Bluebird Bio. M.J.E. received consulting fees from Abbvie, Sermonix, Pfizer, AstraZeneca, Celgene, NanoString, Puma, Veracyte, Eli Lilly, and Novartis, and he is an equity stockholder and Board of Directors member of BioClassifier. M.J.E. is an inventor on a patent for the Breast Cancer PAM50-based assay, Prosigna, which is marketed by Veracyte. M.J.E. also receives royalties from Washington University in St Louis when the WHIM PDX lines are licensed to for-profit companies., (© 2022.)

Crosstalk between metabolic and signaling events that induce tumor metastasis remains elusive. Here, we determine how oncogenic sphingosine 1-phosphate (S1P) metabolism induces intracellular C3 complement activation to enhance migration/metastasis. We demonstrate that increased S1P metabolism activates C3 complement processing through S1P receptor 1 (S1PR1). S1P/S1PR1-activated intracellular C3b-α' 2 is associated with PPIL1 through glutamic acid 156 (E156) and aspartic acid 111 (D111) residues, resulting in NLRP3/inflammasome induction. Inactivation mutations of S1PR1 to prevent S1P signaling or mutations of C3b-α' 2 to prevent its association with PPIL1 attenuate inflammasome activation and reduce lung colonization/metastasis in mice. Also, activation of the S1PR1/C3/PPIL1/NLRP3 axis is highly associated with human metastatic melanoma tissues and patient-derived xenografts. Moreover, targeting S1PR1/C3/PPIL1/NLRP3 signaling using molecular, genetic, and pharmacologic tools prevents lung colonization/metastasis of various murine cancer cell lines using WT and C3a-receptor1 knockout (C3aR1 -/- ) mice. These data provide strategies for treating high-grade/metastatic tumors by targeting the S1PR1/C3/inflammasome axis., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The COVID-19 pandemic had a relevant impact on the organization of intensive care units (ICU) and may have reduced the overall compliance with healthcare-associated infections (HAIs) prevention programs. Invasively ventilated patients are at high risk of ICU-associated infection, but there is little evidence regarding the impact of the pandemic on their occurrence in non-COVID-19 patients. Moreover, little is known of antibiotic prescription trends in the ICU during the first wave of the pandemic. The purpose of this investigation is to assess the incidence, characteristics, and risk factors for ICU-associated HAIs in a population of invasively ventilated patients affected by non-COVID-19 acute respiratory failure (ARF) admitted to the ICU in the first wave of the COVID-19 pandemic, and to evaluate the ICU antimicrobial prescription strategies. Moreover, we compared HAIs and antibiotic use to a cohort of ARF patients admitted to the ICU the year before the pandemic during the same period., Methods: this is a retrospective, single-centered cohort study conducted at S. Anna University Hospital (Ferrara, Italy). We enrolled patients admitted to the ICU for acute respiratory failure requiring invasive mechanical ventilation (MV) between February and April 2020 (intra-pandemic group, IP) and February and April 2019 (before the pandemic group, PP). We excluded patients admitted to the ICU for COVID-19 pneumonia. We recorded patients' baseline characteristics, ICU-associated procedures and devices. Moreover, we evaluated antimicrobial therapy and classified it as prophylactic, empirical or target therapy, according to the evidence of infection at the time of prescription and to the presence of a positive culture sample. We compared the results of the two groups (PP and IP) to assess differences between the two years., Results: One hundred and twenty-eight patients were screened for inclusion and 83 patients were analyzed, 45 and 38 in the PP and I group, respectively. We found a comparable incidence of HAIs (62.2% vs. 65.8%, p = 0.74) and multidrug-resistant (MDR) isolations (44.4% vs. 36.8% p = 0.48) in the two groups. The year of ICU admission was not independently associated with an increased risk of developing HAIs (OR = 0.35, 95% CI 0.16-1.92, p = 0.55). The approach to antimicrobial therapy was characterized by a significant reduction in total antimicrobial use (21.4 ± 18.7 vs. 11.6 ± 9.4 days, p = 0.003), especially of target therapy, in the IP group., Conclusions: ICU admission for non-COVID-19 ARF during the first wave of the SARS-CoV-2 pandemic was not associated with an increased risk of ICU-associated HAIs. Nevertheless, ICU prescription of antimicrobial therapy changed and significantly decreased during the pandemic., Competing Interests: The authors declare no conflict of interest.

Background: Management of advanced chordomas remains delicate considering their insensitivity to chemotherapy. Homozygous deletion of the regulatory gene CDKN2A has been described as the most frequent genetic alteration in chordomas and may be considered as a potential theranostic marker. Here, we evaluated the tumor efficacy of the CDK4/6 inhibitor palbociclib, as well as the PLK1 inhibitor volasertib, in three chordoma patient-derived xenograft (PDX) models to validate and identify novel therapeutic approaches., Methods: From our chordoma xenograft panel, we selected three models, two of them harboring a homozygous deletion of CDKN2A/2B genes, and the last one a PBRM1 pathogenic variant (as control). For each model, we tested the palbociclib and volasertib drugs with pharmacodynamic studies together with RT-PCR and RNAseq analyses., Results: For palbociclib, we observed a significant tumor response for one of two models harboring the deletion of CDKN2A/2B (p = 0.02), and no significant tumor response in the PBRM1 -mutated PDX; for volasertib, we did not observe any response in the three tested models. RT-PCR and RNAseq analyses showed a correlation between cell cycle markers and responses to palbociclib; finally, RNAseq analyses showed a natural enrichment of the oxidative phosphorylation genes (OxPhos) in the palbociclib-resistant PDX (p = 0.02)., Conclusion: CDK4/6 inhibition appears as a promising strategy to manage advanced chordomas harboring a loss of CDKN2A/2B . However, further preclinical studies are strongly requested to confirm it and to understand acquired or de novo resistance to palbociclib, in the peculiar view of a targeting of the oxidative phosphorylation genes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Passeri, Dahmani, Masliah-Planchon, El Botty, Courtois, Vacher, Marangoni, Nemati, Roman-Roman, Adle-Biassette, Mammar, Froelich, Bièche and Decaudin.)

Backgorund: Prior data suggest pre-diagnostic aspirin use impacts breast tumour biology and patient outcome. Here, we employed faithful surgical resection models of HER2+ and triple-negative breast cancer (TNBC), to study outcome and response mechanisms across breast cancer subtypes., Method: NOD/SCID mice were implanted with HER2+ MDA-MB-231/LN/2-4/H2N, trastuzumab-resistant HER2+ HCC1954 or a TNBC patient-derived xenograft (PDX). A daily low-dose aspirin regimen commenced until primary tumours reached ~250 mm 3 and subsequently resected. MDA-MB-231/LN/2-4/H2N mice were monitored for metastasis utilising imaging. To interrogate the survival benefit of pre-treatment aspirin, 3 weeks post-resection, HCC1954/TNBC animals received standard-of-care (SOC) chemotherapy for 6 weeks. Primary tumour response to aspirin was interrogated using immunohistochemistry., Results: Aspirin delayed time to metastasis in MDA-MB-231/LN/2-4/H2N xenografts and decreased growth of HER2 + /TNBC primary tumours. Lymphangiogenic factors and lymph vessels number were decreased in HER2 + tumours. However, no survival benefit was seen in aspirin pre-treated animals (HCC1954/TNBC) that further received adjuvant SOC, compared with animals treated with SOC alone. In an effort to study mechanisms responsible for the observed reduction in lymphangiogenesis in HER2 + BC we utilised an in vitro co-culture system of HCC1954 tumour cells and mesenchymal stromal cells (MSC). Aspirin abrogated the secretion of VEGF-C in MSCs and also decreased the lymph/angiogenic potential of the MSCs and HCC1954 by tubule formation assay. Furthermore, aspirin decreased the secretion of uPA in HCC1954 cells potentially diminishing its metastatic capability., Conclusion: Our data employing clinically relevant models demonstrate that aspirin alters breast tumour biology. However, aspirin may not represent a robust chemo-preventative agent in the HER2 + or TNBC setting., (© 2022 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Two pyrazolone-based hydrazones H 2 L' [in general, H 2 L'; in detail, H 2 L 1 = 5-methyl-2-phenyl-4-(2-phenyl-1-(2-(4-(trifluoromethyl)phenyl)hydrazineyl)ethyl)-2,4-dihydro-3 H -pyrazol-3-one, H 2 L 2 = ( Z )-5-methyl-2-phenyl-4-(2-phenyl-1-(2-(pyridin-2-yl)hydrazineyl)ethylidene)-2,4-dihydro-3 H -pyrazol-3-one] were reacted with Zn(II) and Cu(II) acceptors affording the complexes [Zn(HL 1 ) 2 (MeOH) 2 ], [Cu(HL 1 ) 2 ], and [M(HL 2 ) 2 ] (M = Cu or Zn). X-ray and DFT studies showed the free proligands to exist in the N-H,N-H tautomeric form and that in [Zn(HL 1 ) 2 (MeOH) 2 ], zinc is six-coordinated by the N,O-chelated (HL 1 ) ligand and other two oxygen atoms of coordinated methanol molecules, while [Cu(HL 1 ) 2 ] adopts a square planar geometry with the two (HL 1 ) ligands in anti-conformation. Finally, the [M(HL 2 ) 2 ] complexes are octahedral with the two (HL 2 ) ligands acting as κ-O,N,N-donors in planar conformation. Both the proligands and metal complexes were tested against the parasite Trypanosoma brucei and Balb3T3 cells. The Zn(II) complexes were found to be very powerful, more than the starting proligands, while maintaining a good safety level. In detail, H 2 L 1 and its Zn(II) complex have high selective index (55 and >100, respectively) against T. brucei compared to the mammalian Balb/3T3 reference cells. These results encouraged the researchers to investigate the mechanism of action of these compounds that have no structural relations with the already known drugs used against T. brucei . Interestingly, the analysis of NTP and dNTP pools in T. brucei treated by H 2 L 1 and its Zn(II) complex showed that the drugs had a strong impact on the CTP pools, making it likely that CTP synthetase is the targeted enzyme.

Synthetic lethal interactions, where the simultaneous but not individual inactivation of two genes is lethal to the cell, have been successfully exploited to treat cancer. GATA3 is frequently mutated in estrogen receptor (ER)-positive breast cancers and its deficiency defines a subset of patients with poor response to hormonal therapy and poor prognosis. However, GATA3 is not yet targetable. Here we show that GATA3 and MDM2 are synthetically lethal in ER-positive breast cancer. Depletion and pharmacological inhibition of MDM2 significantly impaired tumor growth in GATA3-deficient models in vitro, in vivo and in patient-derived organoids/xenograft (PDOs/PDX) harboring GATA3 somatic mutations. The synthetic lethality requires p53 and acts via the PI3K/Akt/mTOR pathway. Our results present MDM2 as a therapeutic target in the substantial cohort of ER-positive, GATA3-mutant breast cancer patients. With MDM2 inhibitors widely available, our findings can be rapidly translated into clinical trials to evaluate in-patient efficacy., (© 2022. The Author(s).)

Estrogen receptor-positive breast cancer is a highly prevalent but heterogeneous disease among women. Advanced molecular stratification is required to enable individually most efficient treatments based on relevant prognostic and predictive biomarkers. First objective of our study was the hypothesis-driven discovery of biomarkers involved in tumor progression upon xenotransplantation of Luminal breast cancer into humanized mice. The second objective was the marker validation and correlation with the clinical outcome of Luminal breast cancer disease within the GeparTrio trial. An elevated mdm2 gene copy number was associated with enhanced tumor growth and lung metastasis in humanized tumor mice. The viability, proliferation and migration capacity of inherently mdm2 positive breast cancer cells in vitro were significantly reduced upon mdm2 knockdown or anti-mdm2 targeting. An mdm2 gain significantly correlated with a worse DFS and OS of Luminal breast cancer patients, albeit it was also associated with an enhanced preoperative pathological response rate. We provide evidence for an enhanced Luminal breast cancer stratification based on mdm2. Moreover, mdm2 can potentially be utilized as a therapeutic target in the Luminal subtype., (© 2021 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

The persistence of cancer cells resistant to therapy remains a major clinical challenge. In triple-negative breast cancer, resistance to chemotherapy results in the highest recurrence risk among breast cancer subtypes. The drug-tolerant state seems largely defined by nongenetic features, but the underlying mechanisms are poorly understood. Here, by monitoring epigenomes, transcriptomes and lineages with single-cell resolution, we show that the repressive histone mark H3K27me3 (trimethylation of histone H3 at lysine 27) regulates cell fate at the onset of chemotherapy. We report that a persister expression program is primed with both H3K4me3 (trimethylation of histone H3 at lysine 4) and H3K27me3 in unchallenged cells, with H3K27me3 being the lock to its transcriptional activation. We further demonstrate that depleting H3K27me3 enhances the potential of cancer cells to tolerate chemotherapy. Conversely, preventing H3K27me3 demethylation simultaneously to chemotherapy inhibits the transition to a drug-tolerant state, and delays tumor recurrence in vivo. Our results highlight how chromatin landscapes shape the potential of cancer cells to respond to initial therapy., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: PI3K signaling is frequently activated in breast cancer and is targeted by PI3K inhibitors. However, resistance of tumor cells to PI3K inhibition, often mediated by activated receptor tyrosine kinases, is commonly observed and reduces the potency of PI3K inhibitors. Therefore, new treatment strategies to overcome resistance to PI3K inhibitors are urgently needed to boost their efficacy. The phosphatase SHP2, which plays a crucial role in mediating signal transduction between receptor tyrosine kinases and both the PI3K and MAPK pathways, is a potential target for combination treatment., Methods: We tested combinations of PI3K and SHP2 inhibitors in several experimental breast cancer models that are resistant to PI3K inhibition. Using cell culturing, biochemical and genetic approaches, we evaluated tumor cell proliferation and signaling output in cells treated with PI3K and SHP2 inhibitors., Results: Combination treatment with PI3K and SHP2 inhibitors counteracted both acquired and intrinsic breast cancer cell resistance to PI3K inhibition that is mediated by activated receptor tyrosine kinases. Dual PI3K and SHP2 inhibition blocked proliferation and led to sustained inactivation of PI3K and MAPK signaling, where resistant cells rapidly re-activated these pathways upon PI3K inhibitor monotreatment. In addition, we demonstrate that overexpression of SHP2 induced resistance to PI3K inhibition, and that SHP2 was frequently activated during the development of PI3K inhibitor resistance after prolonged treatment of sensitive cells., Conclusions: Our results highlight the importance of SHP2 as a player in resistance to PI3K inhibitors. Combination treatment with PI3K and SHP2 inhibitors could pave the way for significant improvements in therapies for breast cancer., (© 2022. The Author(s).)

Mechanically ventilated patients with ARDS due to the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) seem particularly susceptible to AKI. Our hypothesis was that the renal blood flow could be more compromised in SARS-CoV-2 patients than in patients with "classical" ARDS. We compared the renal resistivity index (RRI) and the renal venous flow (RVF) in ARDS patients with SARS-CoV-2 and in ARDS patients due to other etiologies. Prospective, observational pilot study performed on 30 mechanically ventilated patients (15 with SARS-COV-2 ARDS and 15 with ARDS). Mechanical ventilation settings included constant-flow controlled ventilation, a tidal volume of 6 ml/kg of ideal body weight and the PEEP level titrated to the lowest driving pressure. Ultrasound Doppler measurements of RRI and RVF pattern were performed in each patient. Patients with SARS-COV-2 ARDS had higher RRI than patients with ARDS (0.71[0.67-0.78] vs 0.64[0.60-0.74], p = 0.04). RVF was not-continuous in 9/15 patients (71%) in the SARS-COV-2 ARDS group and in and 5/15 (33%) in the ARDS group (p = 0.27). A linear correlation was found between PEEP and RRI in patients with SARS-COV-2 ARDS (r 2  = 0.31; p = 0.03) but not in patients with ARDS. Occurrence of AKI was 53% in patients with SARS-COV-2 ARDS and 33% in patients with ARDS (p = 0.46). We found a more pronounced impairment in renal blood flow in mechanically ventilated patients with SARS-COV-2 ARDS, compared with patients with "classical" ARDS., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature.)

Lack of preclinical patient-derived xenograft cancer models in which to conduct large-scale molecular studies seriously impairs the development of effective personalized therapies. We report here an in vivo concept consisting of implanting human tumor cells in targeted tissues of an avian embryo, delivering therapeutics, evaluating their efficacy by measuring tumors using light sheet confocal microscopy, and conducting large-scale RNA-seq analysis to characterize therapeutic-induced changes in gene expression. The model was established to recapitulate triple-negative breast cancer (TNBC) and validated using TNBC standards of care and an investigational therapeutic agent., Competing Interests: V.C. and C.D.-B. are co-founders of OncoFactory SAS (www.oncofactory.com). L.J., C.C., and R.T. are employees of OncoFactory SAS. F. Gallix, S.C., F. Gay, and K.A. are employees of Erytech Pharma. This work is related to the international patent WO2017/103,025., (© 2021 The Authors.)

Under conditions of starvation, normal and tumor epithelial cells can rewire their metabolism toward the consumption of extracellular proteins, including extracellular matrix-derived components as nutrient sources. The mechanism of pericellular matrix degradation by starved cells has been largely overlooked. Here it is shown that matrix degradation by breast and pancreatic tumor cells and patient-derived xenograft explants increases by one order of magnitude upon amino acid and growth factor deprivation. In addition, it is found that collagenolysis requires the invadopodia components, TKS5, and the transmembrane metalloproteinase, MT1-MMP, which are key to the tumor invasion program. Increased collagenolysis is controlled by mTOR repression upon nutrient depletion or pharmacological inhibition by rapamycin. The results reveal that starvation hampers clathrin-mediated endocytosis, resulting in MT1-MMP accumulation in arrested clathrin-coated pits. The study uncovers a new mechanism whereby mTOR repression in starved cells leads to the repurposing of abundant plasma membrane clathrin-coated pits into robust ECM-degradative assemblies., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Transpulmonary driving pressure (DP L ) corresponds to the cyclical stress imposed on the lung parenchyma during tidal breathing and, therefore, can be used to assess the risk of ventilator-induced lung injury (VILI). Its measurement at the bedside requires the use of esophageal pressure (Peso), which is sometimes technically challenging. Recently, it has been demonstrated how in an animal model of ARDS, the transpulmonary pressure (P L ) measured with Peso calculated with the absolute values method (P L = Paw-Peso) is equivalent to the transpulmonary pressure directly measured using pleural sensors in the central-dependent part of the lung. We hypothesized that, since the P L derived from Peso reflects the regional behavior of the lung, it could exist a relationship between regional parameters measured by electrical impedance tomography (EIT) and driving P L (DP L ). Moreover, we explored if, by integrating airways pressure data and EIT data, it could be possible to estimate non-invasively DP L and consequently lung elastance (EL) and elastance-derived inspiratory P L (PI). We analyzed 59 measurements from 20 patients with ARDS. There was a significant intra-patient correlation between EIT derived regional compliance in regions of interest (ROI1) ( r = 0.5, p = 0.001), ROI2 ( r = -0.68, p < 0.001), and ROI3 ( r = -0.4, p = 0.002), and DP L . A multiple linear regression successfully predicted DP L based on respiratory system elastance (Ers), ideal body weight (IBW), roi1%, roi2%, and roi3% ( R 2 = 0.84, p < 0.001). The corresponding Bland-Altmann analysis showed a bias of -1.4e-007 cmH 2 O and limits of agreement (LoA) of -2.4-2.4 cmH 2 O. EL and PI calculated using EIT showed good agreement ( R 2 = 0.89, p < 0.001 and R 2 = 0.75, p < 0.001) with the esophageal derived correspondent variables. In conclusion, DP L has a good correlation with EIT-derived parameters in the central lung. DP L , PI, and EL can be estimated with good accuracy non-invasively combining information coming from EIT and airway pressure., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Scaramuzzo, Spadaro, Spinelli, Waldmann, Bohm, Ottaviani, Montanaro, Gamberini, Marangoni, Mauri and Volta.)

Despite the availability of multiple human epidermal growth factor receptor 2-targeted (HER2-targeted) treatments, therapeutic resistance in HER2+ breast cancer remains a clinical challenge. Intratumor heterogeneity for HER2 and resistance-conferring mutations in the PIK3CA gene (encoding PI3K catalytic subunit α) have been investigated in response and resistance to HER2-targeting agents, while the role of divergent cellular phenotypes and tumor epithelial-stromal cell interactions is less well understood. Here, we assessed the effect of intratumor cellular genetic heterogeneity for ERBB2 (encoding HER2) copy number and PIK3CA mutation on different types of neoadjuvant HER2-targeting therapies and clinical outcome in HER2+ breast cancer. We found that the frequency of cells lacking HER2 was a better predictor of response to HER2-targeted treatment than intratumor heterogeneity. We also compared the efficacy of different therapies in the same tumor using patient-derived xenograft models of heterogeneous HER2+ breast cancer and single-cell approaches. Stromal determinants were better predictors of response than tumor epithelial cells, and we identified alveolar epithelial and fibroblastic reticular cells as well as lymphatic vessel endothelial hyaluronan receptor 1-positive (Lyve1+) macrophages as putative drivers of therapeutic resistance. Our results demonstrate that both preexisting and acquired resistance to HER2-targeting agents involve multiple mechanisms including the tumor microenvironment. Furthermore, our data suggest that intratumor heterogeneity for HER2 should be incorporated into treatment design.

Background: Endocrine therapies targeting estrogen signaling have significantly improved breast cancer (BC) patient survival, although 40% of ERα-positive BCs do not respond to those therapies. Aside from genomic signaling, estrogen triggers non-genomic pathways by forming a complex containing methylERα/Src/PI3K, a hallmark of aggressiveness and resistance to tamoxifen. We aimed to confirm the prognostic value of this complex and investigated whether its targeting could improve tumor response in vivo., Methods: The interaction of ERα/Src and ERα/PI3K was studied by proximity ligation assay (PLA) in a cohort of 440 BC patients. We then treated patient-derived BC xenografts (PDXs) with fulvestrant or the PI3K inhibitor alpelisib (BYL719) alone or in combination. We analyzed their anti-proliferative effects on 6 ERα+ and 3 ERα- PDX models. Genomic and non-genomic estrogen signaling were assessed by measuring ERα/PI3K interaction by PLA and the expression of estrogen target genes by RT-QPCR, respectively., Results: We confirmed that ERα/Src and ERα/PI3K interactions were associated with a trend to poorer survival, the latter displaying the most significant effects. In ERα+ tumors, the combination of BYL719 and fulvestrant was more effective than fulvestrant alone in 3 models, irrespective of PI3K, PTEN status, or ERα/PI3K targeting. Remarkably, resistance to fulvestrant was associated with non-genomic ERα signaling, since genomic degradation of ERα was unaltered in these tumors, whereas the treatment did not diminish the level of ERα/PI3K interaction. Interestingly, in 2 ERα- models, fulvestrant alone impacted tumor growth, and this was associated with a decrease in ERα/PI3K interaction., Conclusions: Our results demonstrate that ERα/PI3K may constitute a new prognostic marker, as well as a new target in BC. Indeed, resistance to fulvestrant in ERα+ tumors was associated with a lack of impairment of ERα/PI3K interaction in the cytoplasm. In addition, an efficient targeting of ERα/PI3K in ERα- tumors could constitute a promising therapeutic option.