AXL – a new player in resistance to HER2 blockade

Cancer; HER2 disease; ResistanceCàncer; Malaltia HER2; ResistènciaCáncer; Enfermedad HER2; ResistenciaHER2 is a driver in solid tumors, mainly breast, oesophageal and gastric cancer, through activation of oncogenic signaling pathways such as PI3K or MAPK. HER2 overexpression associates with aggressive disease and poor prognosis. Despite targeted anti-HER2 therapy has improved outcomes and is the current standard of care, resistance emerge in some patients, requiring additional therapeutic strategies. Several mechanisms, including the upregulation of receptors tyrosine kinases such as AXL, are involved in resistance. AXL signaling leads to cancer cell proliferation, survival, migration, invasion and angiogenesis and correlates with poor prognosis. In addition, AXL overexpression accompanied by a mesenchymal phenotype result in resistance to chemotherapy and targeted therapies. Preclinical studies show that AXL drives anti-HER2 resistance and metastasis through dimerization with HER2 and activation of downstream pathways in breast cancer. Moreover, AXL inhibition restores response to HER2 blockade in vitro and in vivo. Limited data in gastric and oesophageal cancer also support these evidences. Furthermore, AXL shows a strong value as a prognostic and predictive biomarker in HER2+ breast cancer patients, adding a remarkable translational relevance. Therefore, current studies enforce the potential of co-targeting AXL and HER2 to overcome resistance and supports the use of AXL inhibitors in the clinic

Delivery of miR-200c-3p Using Tumor-Targeted Mesoporous Silica Nanoparticles for Breast Cancer Therapy

[EN] Despite advancesin breast cancer treatment, it remainsthe leadingcause of cancer-related death in women worldwide. In this context,microRNAs have emerged as potential therapeutic targets but stillpresent some limitations for in vivo applications.Particularly, miR-200c-3p is a well-known tumor suppressor microRNAthat inhibits tumor progression and metastasis in breast cancer throughdownregulating ZEB1 and ZEB2. Basedon the above, we describe the design and validation of a nanodeviceusing mesoporous silica nanoparticles for miR-200c-3p delivery forbreast cancer treatment. We demonstrate the biocompatibility of thesynthesized nanodevices as well as their ability to escape from endosomes/lysosomesand inhibit tumorigenesis, invasion, migration, and proliferationof tumor cells in vitro. Moreover, tumor targetingand effective delivery of miR-200c-3p from the nanoparticles in vivo are confirmed in an orthotopic breast cancer mousemodel, and the therapeutic efficacy is also evidenced by a decreasein tumor size and lung metastasis, while showing no signs of toxicity.Overall, our results provide evidence that miR-200c-3p-loaded nanoparticlesare a potential strategy for breast cancer therapy and a safe andeffective system for tumor-targeted delivery of microRNAs.This research was supported by project PID2021-126304OB-C41 funded by MCIN/AEI/10.13039/501100011033/ and by European Regional Development Fund A way of doing Europe. Also, this study forms part of the Advanced Materials program (MFA/2022/049) and was supported by MCIN with funding from European Union NextGeneration EU(PRTR-C17.I1) and by Generalitat Valenciana. This study was also supported by Generalitat Valenciana (CIPROM/2021/007). This research was also supported by CIBER Consorcio Centro de Investigación Biomédica en Red CIBER-BBN(CB07/01/2012), CIBERONC(CB16/12/00481), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación. This work was also supported by Spanish Government and cofinanced by FEDER Funds (PI18/01219, PI21/01351) .I.G.-C. was funded by Margarita Salas post doctoral grant (European Union-Nextgeneration EU). A.A.-A. and A.L. were funded by Asociación Española Contra el Cancer.J.F.B. was funded by Instituto de Salud Carlos III and the European Social Fund for the financial support 'Sara Borrell' (CD19/00038). V.C.-N. was funded by Ministerio de Ciencia e Innovacio¿n (FPU grant), and J.M.C. was funded by Sociedad Española de Oncología Médica (Río Hortega-SEOM)Garrido-Cano, I.; Adam-Artigues, A.; Lameirinhas, A.; Blandez, JF.; Candela-Noguera, V.; Lluch, A.; Bermejo, B.... (2023). Delivery of miR-200c-3p Using Tumor-Targeted Mesoporous Silica Nanoparticles for Breast Cancer Therapy. ACS Applied Materials & Interfaces. 15(32):38323-38334. https://doi.org/10.1021/acsami.3c075413832338334153

MiRNA-449 family is epigenetically repressed and sensitizes to doxorubicin through ACSL4 downregulation in triple-negative breast cancer

[EN] Despite progress in breast cancer treatment, a significant portion of patients still relapse because of drug resistance. The involvement of microRNAs in cancer progression and chemotherapy response is well established. Therefore, this study aimed to elucidate the dysregulation of the microRNA-449 family (specifically, microRNA-449a, microRNA-449b-5p, and microRNA-449c-5p) and its impact on resistance to doxorubicin, a commonly used chemotherapeutic drug for the treatment of triple-negative breast cancer. We found that the microRNA-449 family is downregulated in triple-negative breast cancer and demonstrated its potential as a diagnostic biomarker. Besides, our findings indicate that the downregulation of the microRNA-449 family is mediated by the microRNAs-449/SIRT1-HDAC1 negative feedback loop. Moreover, it was found that the microRNA-449 family dysregulates the fatty acid metabolism by targeting ACSL4, which is a potential prognostic biomarker that mediates doxorubicin response through regulation of the drug extrusion pump ABCG2. Altogether, our results suggest that the microRNA-449 family might be a potential therapeutic target for the treatment of triple-negative breast cancer since it is implicated in doxorubicin response through ACSL4/ABCG2 axis regulation. Ultimately, our results also highlight the value of microRNAs-449 and ACSL4 as diagnostic and prognostic biomarkers in triple-negative breast cancer.This work was supported by the Spanish Government and cofinanced by FEDER Funds (AES Program, grants PI21/01351, PI21/00142, CIBERONC, Biomedical Research Networking Centre for Cancer CB16/12/00241, and CB16/12/00481). STR was founded by Conselleria d'Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana (ACIF/2019/119). IGC was founded by Margarita Salas's postdoctoral grant (European Union-Next generation EU). AL was founded by Asociacion Espanola Contra el Cancer(PRDVA19016LAME). JMC was founded by Sociedad Espanola de Oncologia Medica(Rio Hortega-SEOM)Torres-Ruiz, S.; Garrido-Cano, I.; Lameirinhas, A.; Burgués, O.; Hernando, C.; Martínez, MT.; Rojo, F.... (2024). MiRNA-449 family is epigenetically repressed and sensitizes to doxorubicin through ACSL4 downregulation in triple-negative breast cancer. CELL DEATH DISCOVERY. 10(1). https://doi.org/10.1038/s41420-024-02128-710

MicroRNA-33b Suppresses Epithelial-Mesenchymal Transition Repressing the MYC-EZH2 Pathway in HER2+ Breast Carcinoma

Downregulation of miR-33b has been documented in many types of cancers and is being involved in proliferation, migration, and epithelial-mesenchymal transition (EMT). Furthermore, the enhancer of zeste homolog 2-gene (EZH2) is a master regulator of controlling the stem cell differentiation and the cell proliferation processes. We aim to evaluate the implication of miR-33b in the EMT pathway in HER2+ breast cancer (BC) and to analyze the role of EZH2 in this process as well as the interaction between them. miR-33b is downregulated in HER2+ BC cells vs healthy controls, where EZH2 has an opposite expression in vitro and in patients' samples. The upregulation of miR-33b suppressed proliferation, induced apoptosis, reduced invasion, migration and regulated EMT by an increase of E-cadherin and a decrease of ß-catenin and vimentin. The silencing of EZH2 mimicked the impact of miR-33b overexpression. Furthermore, the inhibition of miR-33b induces cell proliferation, invasion, migration, EMT, and EZH2 expression in non-tumorigenic cells. Importantly, the Kaplan-Meier analysis showed a significant association between high miR-33b expression and better overall survival. These results suggest miR-33b as a suppressive miRNA that could inhibit tumor metastasis and invasion in HER2+ BC partly by impeding EMT through the repression of the MYC-EZH2 loop

SOLTI-1805 TOT-HER3 Study Concept: A Window-of-Opportunity Trial of Patritumab Deruxtecan, a HER3 Directed Antibody Drug Conjugate, in Patients With Early Breast Cancer

Background: Preclinical data support a key role for the human epidermal growth factor receptor 3 (HER3) pathway in hormone receptor (HR)-positive breast cancer. Recently, new HER3 directed antibody drug conjugates have shown activity in breast cancer. Given the need to better understand the molecular biology, tumor microenvironment, and mechanisms of drug resistance in breast cancer, we designed this window-of-opportunity study with the HER3 directed antibody drug conjugate patritumab deruxtecan (HER3-DXd; U3-1402). Trial Design: Based on these data, a prospective, multicenter, single-arm, window-of-opportunity study was designed to evaluate the biological effect of patritumab deruxtecan in the treatment of naïve patients with HR-positive/HER2-negative early breast cancer whose primary tumors are ≥1 cm by ultrasound evaluation. Patients will be enrolled in four cohorts according to the mRNA-based ERBB3 expression by central assessment. The primary endpoint is a CelTIL score after one single dose. A translational research plan is also included to provide biological information and to evaluate secondary and exploratory objectives of the study

The GATA3 X308_Splice breast cancer mutation is a hormone context-dependent oncogenic driver

As the catalog of oncogenic driver mutations is expanding, it becomes clear that alterations in a given gene might have different functions and should not be lumped into one class. The transcription factor GATA3 is a paradigm of this. We investigated the functions of the most common GATA3 mutation (X308_Splice) and five additional mutations, which converge into a neoprotein that we called “neoGATA3,” associated with excellent prognosis in patients. Analysis of available molecular data from >3000 breast cancer patients revealed a dysregulation of the ER-dependent transcriptional response in tumors carrying neoGATA3-generating mutations. Mechanistic studies in vitro showed that neoGATA3 interferes with the transcriptional programs controlled by estrogen and progesterone receptors, without fully abrogating them. ChIP-Seq analysis indicated that ER binding is reduced in neoGATA3-expressing cells, especially at distal regions, suggesting that neoGATA3 interferes with the fine tuning of ER-dependent gene expression. This has opposite outputs in distinct hormonal context, having pro- or anti-proliferative effects, depending on the estrogen/progesterone ratio. Our data call for functional analyses of putative cancer drivers to guide clinical application.Institute of Cancer Research of the Medical University Vienna and by the grant P27361-B23 from the Austrian Science Grant (FWF), FXR was supported by SAF2011-29530 and SAF2015-70553-R grants from Ministerio de Economía y Competitividad (Madrid, Spain) (co-funded by the ERDF-EU), Fundación Científica de la Asociación Española Contra el Cáncer. CNIO is supported by Ministerio de Ciencia, Innovación y Universidades as a Centro de Excelencia Severo Ochoa SEV-2015-051

Clinical, pathological and PAM50 gene expression features of HER2-low breast cancer

Novel antibody-drug conjugates against HER2 are showing high activity in HER2-negative breast cancer (BC) with low HER2 expression (i.e., 1+ or 2+ and lack of ERBB2 amplification). However, the clinical and molecular features of HER2-low BC are yet to be elucidated. Here, we collected retrospective clinicopathological and PAM50 data from 3,689 patients with HER2-negative disease and made the following observations. First, the proportion of HER2-low was higher in HR-positive disease (65.4%) than triple-negative BC (TNBC, 36.6%). Second, within HR-positive disease, ERBB2 and luminal-related genes were more expressed in HER2-low than HER2 0. In contrast, no gene was found differentially expressed in TNBC according to HER2 expression. Third, within HER2-low, ERBB2 levels were higher in HR-positive disease than TNBC. Fourth, HER2-low was not associated with overall survival in HR-positive disease and TNBC. Finally, the reproducibility of HER2-low among pathologists was suboptimal. This study emphasizes the large biological heterogeneity of HER2-low BC, and the need to implement reproducible and sensitive assays to measure low HER2 expression

Patritumab deruxtecan in HER2-negative breast cancer: part B results of the window-of-opportunity SOLTI-1805 TOT-HER3 trial and biological determinants of early response

Patritumab deruxtecan (HER3-DXd) exhibits promising efficacy in breast cancer, with its activity not directly correlated to baseline ERBB3/HER3 levels. This research investigates the genetic factors affecting HER3-DXd's response in women with early-stage hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer. In the SOLTI-1805 TOT-HER3 trial, a single HER3-DXd dose was administered to 98 patients across two parts: 78 patients received 6.4 mg/kg (Part A), and 44 received a lower 5.6 mg/kg dose (Part B). The CelTIL score, measuring tumor cellularity and infiltrating lymphocytes from baseline to day 21, was used to assess drug activity. Part A demonstrated increased CelTIL score after one dose of HER3-DXd. Here we report CelTIL score and safety for Part B. In addition, the exploratory analyses of part A involve a comprehensive study of gene expression, somatic mutations, copy-number segments, and DNA-based subtypes, while Part B focuses on validating gene expression. RNA analyses show significant correlations between CelTIL responses, high proliferation genes (e.g., CCNE1, MKI67), and low expression of luminal genes (e.g., NAT1, SLC39A6). DNA findings indicate that CelTIL response is significantly associated with TP53 mutations, proliferation, non-luminal signatures, and a distinct DNA-based subtype (DNADX cluster-3). Critically, low HER2DX ERBB2 mRNA, correlates with increased HER3-DXd activity, which is validated through in vivo patient-derived xenograft models. This study proposes chemosensitivity determinants, DNA-based subtype classification, and low ERBB2 expression as potential markers for HER3-DXd activity in HER2-negative breast cancer. Patritumab deruxtecan (HER3-DXd) is a promising therapy for breast cancer, targeting HER3. Here, the authors analyse the genomic factors that affect the response to HER3-DXd in patients with early-stage HER2-negative breast cancer as part of the SOLTI-1805 TOT-HER3 clinical trial and report outcomes for Part B of the trial using lower HER3-DXd dose in patients with HER2-negative breast cancer

HOPE (SOLTI-1903) breast cancer study: real-world, patient-centric, clinical practice study to assess the impact of genomic data on next treatment decision-choice in patients with locally advanced or metastatic breast cancer

Background Metastatic breast cancer (mBC) causes nearly all BC-related deaths. Next-generation sequencing (NGS) technologies allow for the application of personalized medicine using targeted therapies that could improve patients' outcomes. However, NGS is not routinely used in the clinical practice and its cost induces access-inequity among patients. We hypothesized that promoting active patient participation in the management of their disease offering access to NGS testing and to the subsequent medical interpretation and recommendations provided by a multidisciplinary molecular advisory board (MAB) could contribute to progressively overcome this challenge. We designed HOPE (SOLTI-1903) breast cancer trial, a study where patients voluntarily lead their inclusion through a digital tool (DT). The main objectives of HOPE study are to empower mBC patients, gather real-world data on the use of molecular information in the management of mBC and to generate evidence to assess the clinical utility for healthcare systems.Trial design After self-registration through the DT, the study team validates eligibility criteria and assists patients with mBC in the subsequent steps. Patients get access to the information sheet and sign the informed consent form through an advanced digital signature. Afterwards, they provide the most recent (preferably) metastatic archival tumor sample for DNA-sequencing and a blood sample obtained at the time of disease progression for ctDNA analysis. Paired results are reviewed by the MAB, considering patient's medical history. The MAB provides a further interpretation of molecular results and potential treatment recommendations, including ongoing clinical trials and further (germline) genetic testing. Participants self-document their treatment and disease evolution for the next 2 years. Patients are encouraged to involve their physicians in the study. HOPE also includes a patient empowerment program with educational workshops and videos about mBC and precision medicine in oncology. The primary endpoint of the study was to describe the feasibility of a patient-centric precision oncology program in mBC patients when a comprehensive genomic profile is available to decide on a subsequent line of treatment

A Pathology-Based Combined Model to Identify PAM50 Non-luminal Intrinsic Disease in Hormone Receptor-Positive HER2-Negative Breast Cancer

Background: In hormone receptor-positive (HR+)/HER2-negative breast cancer, the HER2-enriched and Basal-like intrinsic subtypes are associated with poor outcome, low response to anti-estrogen therapy and high response to chemotherapy. To date, no validated biomarker exists to identify both molecular entities other than gene expression.Methods: PAM50 subtyping and immunohistochemical data were obtained from 8 independent studies of 1,416 HR+/HER2-negative early breast tumors. A non-luminal disease score (NOLUS) from 0 to 100, based on percentage of estrogen receptor (ER), progesterone receptor (PR) and Ki67 tumor cells, was derived in a combined cohort of 5 studies (training dataset) and tested in a combined cohort of 3 studies. The performance of NOLUS was estimated using Area Under the ROC Curve (AUC).Results: In the training dataset (n = 903) and compared to luminal disease, non-luminal disease had lower percentage of ER-positive cells (median 65.2 vs. 86.2%, p < 0.01) and PR-positive cells (33.2 vs. 56.4%, p < 0.01) and higher percentage of Ki67-positive cells (18.2 vs. 13.1%, p = 0.01). A NOLUS formula was derived: −0.45*ER −0.28*PR +0.27*Ki67 + 73.02. The proportion of non-luminal tumors in NOLUS-positive (≥51.38) and NOLUS-negative (<51.38) groups was 52.6 and 8.7%, respectively. In the testing dataset (n = 514), NOLUS was found significantly associated with non-luminal disease (p < 0.01) with an AUC 0.902. The proportion of non-luminal tumors in NOLUS-positive and NOLUS-negative groups was 76.9% (56.4–91.0%) and 2.6% (1.4–4.5%), respectively. The sensitivity and specificity of the pre-specified cutoff was 59.3 and 98.7%, respectively.Conclusions: In the absence of gene expression data, NOLUS can help identify non-luminal disease within HR+/HER2-negative breast cancer