ESR1 gene amplification and MAP3K mutations are selected during adjuvant endocrine therapies in relapsing Hormone Receptor-positive, HER2-negative breast cancer (HR+ HER2- BC)

BACKGROUND

Previous studies have provided a comprehensive picture of genomic alterations in primary and metastatic Hormone Receptor (HR)-positive, Human Epidermal growth factor Receptor 2 (HER2)-negative breast cancer (HR+ HER2- BC). However, the evolution of the genomic landscape of HR+ HER2- BC during adjuvant endocrine therapies (ETs) remains poorly investigated.

METHODS AND FINDINGS

We performed a genomic characterization of surgically resected HR+ HER2- BC patients relapsing during or at the completion of adjuvant ET. Using a customized panel, we comprehensively evaluated gene mutations and copy number variation (CNV) in paired primary and metastatic specimens. After retrieval and quality/quantity check of tumor specimens from an original cohort of 204 cases, 74 matched tumor samples were successfully evaluated for DNA mutations and CNV analysis. Along with previously reported genomic alterations, including PIK3CA, TP53, CDH1, GATA3 and ESR1 mutations/deletions, we found that ESR1 gene amplification (confirmed by FISH) and MAP3K mutations were enriched in metastatic lesions as compared to matched primary tumors. These alterations were exclusively found in patients treated with adjuvant aromatase inhibitors or LHRH analogs plus tamoxifen, but not in patients treated with tamoxifen alone. Patients with tumors bearing MAP3K mutations in metastatic lesions had significantly worse distant relapse-free survival (hazard ratio [HR] 3.4, 95% CI 1.52-7.70, p value 0.003) and worse overall survival (HR 5.2, 95% CI 2.10-12.8, p-value < 0.001) independently of other clinically relevant patient- and tumor-related variables.

CONCLUSIONS

ESR1 amplification and activating MAP3K mutations are potential drivers of acquired resistance to adjuvant ETs employing estrogen deprivation in HR+ HER2- BC. MAP3K mutations are associated with worse prognosis in patients with metastatic disease.

Phenotypic modifications of vascular smooth muscle cells could be responsible for vascular hyporeactivity to contracting agent in mechanically injured rat carotid artery

Vascular smooth muscle cells (VSMCs) that accumulate in neointima after angioplastic injury show different phenotypic characteristics from those of medial layer and an impaired reactivity to contracting agents. The aim of the study was to correlate the vascular hyporesponsiveness to the changes in intracellular calcium concentration [Ca(2+)](i) and the expression of proteins necessary for its utilization in mechanically injured rat carotid arteries (IC) at 14 and 28 days after angioplastic balloon. IC showed a significant reduction (P<0.01) to PE- or KCl-induced contraction as compared to uninjured carotid (UC). Fura-2AM-loaded VSMCs isolated from IC revealed that this hyporeactivity to PE or KCl was accompanied by the impairment of the increase in [Ca(2+)](i) induced by contracting agents in both Ca(2+)-free or -containing medium. Similar results were observed following the ryanodine challenge in VSMC. Western blot analysis showed a significant (P<0.05) reduction in myosin heavy chain (MHC) and IP(3)-type III receptor expression in IC isolated at 14 days from injury compared to UC, while an improvement of these proteins expression was observed at 28 days after damage. On the other hand, in IC tissue, SERCA2 and alpha-actin expression, compared to UC was significantly higher at 14 days than at 28 days. These data indicate that vascular hyporeactivity induced by mechanical injury may be due to alterations of either [Ca(2+)](i) or contractile proteins. These modifications could be related to the changes of VSMC phenotypic characteristics, as supported by the observed modifications in MHC, SERCA2 and alpha-actin expression, proteins considered as biological markers of cellular differentiation.

Dexamethasone improves vascular hyporeactivity induced by LPS in vivo by modulating ATP-sensitive potassium channels activity

(1) Septic shock represents an important risk factor for patients critically ill. This pathology has been largely demonstrated to be a result of a myriad of events. Glucocorticoids represent the main pharmacological therapy used in this pathology. (2) Previously we showed that ATP-sensitive potassium (KATP) channels are involved in delayed vascular hyporeactivity in rats (24 h after Escherichia coli lipopolysaccharide (LPS) injection). In LPS-treated rats, we observed a significant hyporeactivity to phenylephrine (PE) that was reverted by glybenclamide (GLB), and a significant increase in cromakalim (CRK)-induced hypotension. (3) We evaluated the effect of dexamethasone (DEX 8 mg kg-1 i.p.) whether on hyporeactivity to PE or on hyperreactivity to CRK administration, in vivo, in a model of LPS (8 x 106 U kg-1 i.p.)-induced endotoxemia in urethane-anaesthetised rats. (4) DEX treatment significantly reduced, in a time-dependent manner, the increased hypotensive effect induced by CRK in LPS-treated rats. This effect was significantly (P<0.05) reverted by the glucocorticoid receptor antagonist RU38486 (6.6 mg kg-1 i.p.). (5) GLB-induced hypertension (40 mg kg-1 i.p.), in LPS-treated rats, was significantly inhibited by DEX if administered at the same time of LPS. (6) Simultaneous administration of DEX and LPS to rats completely abolished the hyporeactivity to PE observed after 24 h from LPS injection. (7) In conclusion, our results suggest that the beneficial effect of DEX in endotoxemia could be ascribed, at least in part, to its ability to interfere with KATP channel activation induced by LPS. This interaction may explain the improvement of vascular reactivity to PE, mediated by DEX, in LPS-treated rats, highlighting a new pharmacological activity to the well-known anti-inflammatory properties of glucocorticoids.