The Next-Generation Oral Selective Estrogen Receptor Degrader Camizestrant (AZD9833) Suppresses ER+ Breast Cancer Growth and Overcomes Endocrine and CDK4/6 Inhibitor Resistance

Estrogen receptor; Breast cancer; Endocrine inhibitorReceptor d'estrògens; Càncer de mama; Inhibidor endocríReceptores de estrógenos; Cáncer de mama; Inhibidor endocrinoOral 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

Mechanisms of Resistance to PI3K Inhibitors in Cancer: Adaptive Responses, Drug Tolerance and Cellular Plasticity

Inhibidors de la via PI3K; Mecanismes de resistènciaInhibidores de la vía PI3K; Mecanismos de resistenciaPI3K pathway inhibitors; mechanisms of resistanceThe phosphatidylinositol-3-kinase (PI3K) pathway plays a central role in the regulation of several signalling cascades which regulate biological processes such as cellular growth, survival, proliferation, motility and angiogenesis. The hyperactivation of this pathway is linked to tumour progression and is one of the most common events in human cancers. Additionally, aberrant activation of the PI3K pathway has been demonstrated to limit the effectiveness of a number of anti-tumour agents paving the way for the development and implementation of PI3K inhibitors in the clinic. However, the overall effectiveness of these compounds has been greatly limited by inadequate target engagement due to reactivation of the pathway by compensatory mechanisms. Herein, we review the common adaptive responses that lead to reactivation of the PI3K pathway, therapy resistance and potential strategies to overcome these mechanisms of resistance. Furthermore, we highlight the potential role in changes in cellular plasticity and PI3K inhibitor resistance.The work was funded by a start-up grant provided by Curtin University

MiR-182-3p targets TRF2 and impairs tumor growth of triple-negative breast cancer

Target therapy; Telomeres; Triple-negative breast cancerTerapia dirigida; Telómeros; Cáncer de mama triple negativoTeràpia dirigida; Telòmers; Càncer de mama triple negatiuThe telomeric repeat-binding factor 2 (TRF2) is a telomere-capping protein that plays a key role in the maintenance of telomere structure and function. It is highly expressed in different cancer types, and it contributes to cancer progression. To date, anti-cancer strategies to target TRF2 remain a challenge. Here, we developed a miRNA-based approach to reduce TRF2 expression. By performing a high-throughput luciferase screening of 54 candidate miRNAs, we identified miR-182-3p as a specific and efficient post-transcriptional regulator of TRF2. Ectopic expression of miR-182-3p drastically reduced TRF2 protein levels in a panel of telomerase- or alternative lengthening of telomeres (ALT)-positive cancer cell lines. Moreover, miR-182-3p induced DNA damage at telomeric and pericentromeric sites, eventually leading to strong apoptosis activation. We also observed that treatment with lipid nanoparticles (LNPs) containing miR-182-3p impaired tumor growth in triple-negative breast cancer (TNBC) models, including patient-derived tumor xenografts (PDTXs), without affecting mouse survival or tissue function. Finally, LNPs-miR-182-3p were able to cross the blood–brain barrier and reduce intracranial tumors representing a possible therapeutic option for metastatic brain lesions.The research leading to these results has been funded by Italian Association for Cancer Research (AIRC # 21579) and Ministry of Health (CO-2019-12369662) to AB. This work was financially supported by Ministry of Health Ricerca Corrente 2022 and intramural grant-in-aid to EP. RD, LP and EP were supported by AIRC fellowships

Anti-tumoural activity of the G-quadruplex ligand pyridostatin against BRCA1/2-deficient tumours

BRCA2; DNA damage responses; PyridostatinBRCA2; Respostes al dany de l'ADN; PiridostatinaBRCA2; Respuestas al daño del ADN; PiridotatinaThe cells with compromised BRCA1 or BRCA2 (BRCA1/2) function accumulate stalled replication forks, which leads to replication-associated DNA damage and genomic instability, a signature of BRCA1/2-mutated tumours. Targeted therapies against BRCA1/2-mutated tumours exploit this vulnerability by introducing additional DNA lesions. Because homologous recombination (HR) repair is abrogated in the absence of BRCA1 or BRCA2, these lesions are specifically lethal to tumour cells, but not to the healthy tissue. Ligands that bind and stabilise G-quadruplexes (G4s) have recently emerged as a class of compounds that selectively eliminate the cells and tumours lacking BRCA1 or BRCA2. Pyridostatin is a small molecule that binds G4s and is specifically toxic to BRCA1/2-deficient cells in vitro. However, its in vivo potential has not yet been evaluated. Here, we demonstrate that pyridostatin exhibits a high specific activity against BRCA1/2-deficient tumours, including patient-derived xenograft tumours that have acquired PARP inhibitor (PARPi) resistance. Mechanistically, we demonstrate that pyridostatin disrupts replication leading to DNA double-stranded breaks (DSBs) that can be repaired in the absence of BRCA1/2 by canonical non-homologous end joining (C-NHEJ). Consistent with this, chemical inhibitors of DNA-PKcs, a core component of C-NHEJ kinase activity, act synergistically with pyridostatin in eliminating BRCA1/2-deficient cells and tumours. Furthermore, we demonstrate that pyridostatin triggers cGAS/STING-dependent innate immune responses when BRCA1 or BRCA2 is abrogated. Paclitaxel, a drug routinely used in cancer chemotherapy, potentiates the in vivo toxicity of pyridostatin. Overall, our results demonstrate that pyridostatin is a compound suitable for further therapeutic development, alone or in combination with paclitaxel and DNA-PKcs inhibitors, for the benefit of cancer patients carrying BRCA1/2 mutations.Research in A.B. laboratory is supported by grants of Italian Association for Cancer Research (AIRC # 21579), Ministry of Health (CO 2019-12369662) and from IRCCS-Regina Elena Cancer Institute. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 722729 (F.J.G.). Research in M.T. laboratory is supported by Cancer Research UK (DRCPGM\100001), Medical Research Council and University of Oxford. A.R. received support from the UK Medical Research Council grant MC_PC_12006. V.S. received support from Instituto de Salud Carlos III (CPII19/00033, PI17/01080), GHD pink and the FERO Foundation

Alternative academic approaches for testing homologous recombination deficiency in ovarian cancer in the MITO16A/MaNGO-OV2 trial

Molecular testing; Ovarian cancerProves moleculars; Càncer d'ovarisPruebas moleculares; Cáncer de ovariosBackground The detection of homologous recombination deficiency (HRD) can identify patients who are more responsive to platinum and poly ADP ribose polymerase inhibitors (PARPi). MyChoice CDx (Myriad) is the most used HRD test in ovarian cancer (OC). However, some limitations of commercial tests exist, because of the high rate of inconclusive results, costs, and the impossibility of evaluating functional resistance mechanisms. Patients and methods Two academic genomic tests and a functional assay, the RAD51 foci, were evaluated to detect HRD. One hundred patients with high-grade OC enrolled in the MITO16A/MaNGO-OV2 trial and treated with first-line therapy with carboplatin, paclitaxel, and bevacizumab were analyzed. Results The failure rate of the two genomic assays was 2%. The sensitivity in detecting HRD when compared with Myriad was 98.1% and 90.6%, respectively. The agreement rate with Myriad was 0.92 and 0.87, with a Cohen’s κ coefficient corresponding to 0.84 and 0.74, respectively. For the RAD51 foci assay, the failure rate was 30%. When the test was successful, discordant results for deficient and proficient tumors were observed, and additional HRD patients were identified compared to Myriad; sensitivity was 82.9%, agreement rate was 0.65, and Cohen’s κ coefficient was 0.18. The HRD detected by genomic assays and residual tumor at primary surgery and stage was correlated with progression-free survival at multivariate analysis. Conclusions Results suggest the feasibility of academic tests for assessing HRD status that show robust concordance with Myriad and correlation with clinical outcome. The contribution of the functional information related to the RAD51 foci test to the genomic data needs further investigation.This work was supported by funding from the AIRC [grant numbers IG 2016 – ID. 18921 and IG 2021 – ID. 25932 projects – P.I. SP and CO-2018-12367051 (Ministero della Salute) P.I SP]; Ricerca Corrente grant M2/7 from Ministero della Salute to DC, Ricerca Corrente from Ministero della Salute to SP. SM is supported by the Italian Association for Cancer Research [grant number IG-2017 n: IG19997]. MITO16A/MaNGO-OV2 trial was partially supported by Roche. AL is a recipient of a grant from the Asociación Española contra el Cáncer (AECC) [grant number INVES20095LLOP]. VS is a recipient of a grant from the Instituto de Salud Carlos III [grant number CPII19/00033] and a European grant for personalized medicine [grant number ERAPERMED 2019-215]. BP is a recipient of a grant from GOIRC. BP was supported by ESMO with a Clinical Translational Fellowship aid supported by Roche. Any views, opinions, findings, conclusions, or recommendations expressed in this material are those solely of the authors and do not necessarily reflect those of ESMO or Roche. NC has received funding from AstraZeneca (to the institution). FP has received funding from Roche, AstraZeneca, Pfizer, Merck Sharp & Dome, Bayer, Incyte, Taiho Oncology, Janssen Cilag, Exelixis, Aileron, and Daiichi Sankyo (grants to the institution for clinical trial activities)

AKT-mTORC1 reactivation is the dominant resistance driver for PI3Kβ/AKT inhibitors in PTEN-null breast cancer and can be overcome by combining with Mcl-1 inhibitors

Cancer therapeutic resistance; Target identificationResistencia terapéutica contra el cáncer; Identificación de objetivosResistència terapèutica contra el càncer; Identificació d'objectiusThe PI3K pathway is commonly activated in breast cancer, with PI3K-AKT pathway inhibitors used clinically. However, mechanisms that limit or enhance the therapeutic effects of PI3K-AKT inhibitors are poorly understood at a genome-wide level. Parallel CRISPR screens in 3 PTEN-null breast cancer cell lines identified genes mediating resistance to capivasertib (AKT inhibitor) and AZD8186 (PI3Kβ inhibitor). The dominant mechanism causing resistance is reactivated PI3K-AKT-mTOR signalling, but not other canonical signalling pathways. Deletion of TSC1/2 conferred resistance to PI3Kβi and AKTi through mTORC1. However, deletion of PIK3R2 and INPPL1 drove specific PI3Kβi resistance through AKT. Conversely deletion of PIK3CA, ERBB2, ERBB3 increased PI3Kβi sensitivity while modulation of RRAGC, LAMTOR1, LAMTOR4 increased AKTi sensitivity. Significantly, we found that Mcl-1 loss enhanced response through rapid apoptosis induction with AKTi and PI3Kβi in both sensitive and drug resistant TSC1/2 null cells. The combination effect was BAK but not BAX dependent. The Mcl-1i + PI3Kβ/AKTi combination was effective across a panel of breast cancer cell lines with PIK3CA and PTEN mutations, and delivered increased anti-tumor benefit in vivo. This study demonstrates that different resistance drivers to PI3Kβi and AKTi converge to reactivate PI3K-AKT or mTOR signalling and combined inhibition of Mcl-1 and PI3K-AKT has potential as a treatment strategy for PI3Kβi/AKTi sensitive and resistant breast tumours.This work was funded by the Wellcome Trust (WT206194) to KY and MJG and by AstraZeneca to KY, BRD, STB and JTL

Targeting mTOR to overcome resistance to hormone and CDK4/6 inhibitors in ER-positive breast cancer models

Cancer; Cell biologyCàncer; Biologia cel·lularCáncer; Biología celularResistance to therapy remains a major obstacle in cancer management. Although treatment with hormone and CDK4/6 inhibitors is successful in luminal breast cancer, resistance to these treatments is frequent, highlighting the need for novel therapeutic strategies to delay disease progression and improve patient survival. Here, we assessed the mechanisms of acquired resistance using T47D and MCF-7 tamoxifen- and palbociclib-resistant cell-line variants in culture and as xenografts, and patient-derived cells (PDCs) obtained from sensitive or resistant patient-derived xenografts (PDXs). In these models, we analyzed the effect of specific kinase inhibitors on survival, signaling and cellular aggressiveness. Our results revealed that mTOR inhibition is more effective than PI3K inhibition in overcoming resistance, irrespective of PIK3CA mutation status, by decreasing cell proliferation and tumor growth, as well as reducing cell migration and stemness. Moreover, a combination of mTOR and CDK4/6 inhibitors may prevent pathway reactivation downstream of PI3K, interfering with the survival of resistant cells and consequent tumor escape. In conclusion, we highlight the benefits of incorporating mTOR inhibitors into the current therapy in ER + breast cancer. This alternative therapeutic strategy not only enhances the antitumor response but may also delay the emergence of resistance and tumor recurrence.This work was supported by CONICET, ANPCYT (Grants PICT2509 & PICT0345), Instituto Nacional del Cáncer (Grants 2016 & 2018), Fundación Williams, Fundación Bunge & Born (Oster Grant) (Argentina); Instituto de Salud Carlos III (Grants PI20/00892 & CPII19/0033), Ministerio de Economía y Competitividad (FJCI-2015-25412) (Spain)

Olaparib and Ceralasertib (AZD6738) in Patients with Triple-Negative Advanced Breast Cancer: Results from Cohort E of the plasmaMATCH Trial (CRUK/15/010)

Olaparib; Ceralasertib; Triple-negative advanced breast cancerOlaparib; Ceralasertib; Càncer de mama avançat triple negatiuOlaparib; Ceralasertib; Cáncer de mama avanzado triple negativoPurpose: Approximately 10% to 15% of triple-negative breast cancers (TNBC) have deleterious mutations in BRCA1 and BRCA2 and may benefit from PARP inhibitor treatment. PARP inhibitors may also increase exogenous replication stress and thereby increase sensitivity to inhibitors of ataxia telangiectasia and Rad3-related (ATR) protein. This phase II study examined the activity of the combination of PARP inhibitor, olaparib, and ATR inhibitor, ceralasertib (AZD6738), in patients with advanced TNBC. Patients and Methods: Patients with TNBC on most recent biopsy who had received 1 or 2 lines of chemotherapy for advanced disease or had relapsed within 12 months of (neo)adjuvant chemotherapy were eligible. Treatment was olaparib 300 mg twice a day continuously and celarasertib 160 mg on days 1–7 on a 28-day cycle until disease progression. The primary endpoint was confirmed objective response rate (ORR). Tissue and plasma biomarker analyses were preplanned to identify predictors of response. Results: 70 evaluable patients were enrolled. Germline BRCA1/2 mutations were present in 10 (14%) patients and 3 (4%) patients had somatic BRCA mutations. The confirmed ORR was 12/70; 17.1% (95% confidence interval, 10.4–25.5). Responses were observed in patients without germline or somatic BRCA1/2 mutations, including patients with mutations in other homologous recombination repair genes and tumors with functional homologous recombination deficiency by RAD51 foci. Conclusions: The response rate to olaparib and ceralasertib did not meet prespecified criteria for activity in the overall evaluable population, but responses were observed in patients who would not be expected to respond to olaparib monotherapy.This research was funded by the Stand Up to Cancer Campaign for Cancer Research UK (CRUK/15/010, C30746/A19505; to S. Martin, H. Johnson, L. Moretti) with additional support from AstraZeneca, Guardant Health, Bio-Rad and Asociación Española Contra el Cáncer (AECC, INVES20095LLOP; to A. Llop-Guevara). The ICR Clinical Trials and Statistics Unit is supported by the Cancer Research UK core programme grant (C1491/A25351; to L.S. Kilburn). This study represents independent research supported by the National Institute for Health Research (NIHR) Biomedical Research Centre at the Royal Marsden National Health Service Foundation Trust and the Institute of Cancer Research, London, UK. In addition, plasmaMATCH is supported by the NIHR Manchester Clinical Research Facility at the Christie Hospital, Manchester, UK, the NIHR UCLH Clinical Research Facility at University College London Hospitals NHS Foundation Trust, London, UK, the Cancer Research UK Cambridge Centre, Cambridge Biomedical Research Centre (BRC-1215–20014) and Cambridge Experimental Cancer Medicine Centre, Cambridge, UK. The RAD51 analysis was supported with grants from the Spanish Association of Cancer Research and Instituto de Salud Carlos III (ERAPERMED2019–215, CPII19/00033, and INVES20095LLOP). plasmaMATCH is supported at participating sites in England by the NIHR Clinical Research Network, in Scotland by the Chief Scientist Office, and in Wales by Health and Care Research Wales

RAD51 as a biomarker for homologous recombination deficiency in high-grade serous ovarian carcinoma: robustness and interobserver variability of the RAD51 test

Biomarker; High-hrade serous ovarian carcinoma; Homologous recombination deficiencyBiomarcador; Carcinoma de ovario seroso de alto grado; Deficiencia de recombinación homólogaBiomarcador; Carcinoma d'ovari serós d'alt grau; Deficiència de recombinació homòlogaThe RAD51 test is emerging as a promising biomarker for the assessment of functional homologous recombination deficiency (HRD). Yet, the robustness and reproducibility of the immunofluorescence-based RAD51 test, in different academic laboratories, have not been systematically investigated. Therefore, we tested the performance of the RAD51 assay in formalin-fixed paraffin-embedded (FFPE) high-grade serous ovarian carcinoma (HGSOC) samples in four European laboratories. Here, we confirm that subtle differences in staining procedures result in low variability of RAD51 and γH2AX scores. However, substantial variability in RAD51 scoring was observed in some samples, likely due to complicating technical and biological features, such as high RAD51 signal-to-noise ratio and RAD51 heterogeneity. These results support the need to identify and perform additional quality control steps and/or automating image analysis. Altogether, resolving technical issues should be a priority, as identifying tumours with functional HRD is urgently needed to guide the individual treatment of HGSOC patients. Follow-up studies are needed to define the key tissue quality requirements to assess HRD by RAD51 in FFPE tumour samples, as this test could help in guiding the individual treatment of HGSOC patients.This work was supported by the Dutch Cancer Society (KWF) (grant: 12995 to TB and MV) and by ERA PerMed (grant ERAPERMED2019-215 to VS). VS received funding from Instituto de Salud Carlos III (CPII19/00033). ALG received funding from Asociación Española Contra el Cáncer (AECC) (INVES20095LLOP) and AHR from Generalitat de Catalunya (PERIS SLT017/20/000081)

LynX. Panorámica de estudios lingüísticos, nº 16

Panorámica de estudios sobre diferentes ámbitos lingüísticosOverview of studies on different linguistic domain