Phase II trial of eribulin in patients who do not achieve pathologic complete response (pCR) following neoadjuvant chemotherapy.

PURPOSE: Women with residual invasive breast cancer at the primary site or axillary lymph nodes following neoadjuvant chemotherapy have a high risk of recurrence. Eribulin improves survival in patients with metastatic breast cancer who progress after anthracycline and taxane therapy. This phase 2 trial assessed the efficacy of postoperative eribulin in breast cancer patients who did not achieve a pCR following standard neoadjuvant chemotherapy. METHODS: Women with localized breast cancer who had residual invasive cancer following ≥ 4 cycles of standard anthracycline and/or taxane-containing neoadjuvant chemotherapy received adjuvant eribulin treatment. HER2-positive patients also received trastuzumab for 1 year. Adjuvant hormonal therapy and locoregional radiotherapy were administered as per institutional guidelines. Primary endpoint was the 2-year DFS rate. Three patient cohorts were analyzed: TNBC (Cohort A), HR+/HER2- (Cohort B), and HER2+ (Cohort C). RESULTS: One hundred twenty-six patients (Cohort A-53, Cohort B-42, and Cohort C-31) were enrolled. Neoadjuvant chemotherapy included a taxane and an anthracycline in 70%. Eribulin was well tolerated; 84% of patients received the planned 6 cycles. After a median follow-up of 28 months, the 24-month DFS rates were 56% (95% CI 42, 69), 83% (95% CI 67, 91), and 73% (95% CI 53, 86) for Cohorts A, B, and C, respectively. The most common grade 3/4 treatment-related adverse events were neutropenia (26%), leukopenia (13%), and neuropathy (7%). CONCLUSION: Administration of adjuvant eribulin after neoadjuvant chemotherapy was feasible and well tolerated. The 24-month DFS rate did not reach the study target levels in any of the cohorts and was similar to DFS previously described in these cohorts following neoadjuvant chemotherapy alone.

Chronic intermittent alcohol disrupts the GluN2B-associated proteome and specifically regulates group I mGlu receptor-dependent long-term depression.

N-Methyl-d-aspartate receptors (NMDARs) are major targets of both acute and chronic alcohol, as well as regulators of plasticity in a number of brain regions. Aberrant plasticity may contribute to the treatment resistance and high relapse rates observed in alcoholics. Recent work suggests that chronic alcohol treatment preferentially modulates both the expression and subcellular localization of NMDARs containing the GluN2B subunit. Signaling through synaptic and extrasynaptic GluN2B-NMDARs has already been implicated in the pathophysiology of various other neurological disorders. NMDARs interact with a large number of proteins at the glutamate synapse, and a better understanding of how alcohol modulates this proteome is needed. We employed a discovery-based proteomic approach in subcellular fractions of hippocampal tissue from chronic intermittent alcohol (CIE)-exposed C57Bl/6J mice to gain insight into alcohol-induced changes in GluN2B signaling complexes. Protein enrichment analyses revealed changes in the association of post-synaptic proteins, including scaffolding, glutamate receptor and PDZ-domain binding proteins with GluN2B. In particular, GluN2B interaction with metabotropic glutamate (mGlu)1/5 receptor-dependent long-term depression (LTD)-associated proteins such as Arc and Homer 1 was increased, while GluA2 was decreased. Accordingly, we found a lack of mGlu1/5 -induced LTD while α1 -adrenergic receptor-induced LTD remained intact in hippocampal CA1 following CIE. These data suggest that CIE specifically disrupts mGlu1/5 -LTD, representing a possible connection between NMDAR and mGlu receptor signaling. These studies not only demonstrate a new way in which alcohol can modulate plasticity in the hippocampus but also emphasize the utility of this discovery-based proteomic approach to generate new hypotheses regarding alcohol-related mechanisms.

Differential CaMKII regulation by voltage-gated calcium channels in the striatum.

Calcium signaling regulates synaptic plasticity and many other functions in striatal medium spiny neurons to modulate basal ganglia function. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is a major calcium-dependent signaling protein that couples calcium entry to diverse cellular changes. CaMKII activation results in autophosphorylation at Thr286 and sustained calcium-independent CaMKII activity after calcium signals dissipate. However, little is known about the mechanisms regulating striatal CaMKII. To address this, mouse brain slices were treated with pharmacological modulators of calcium channels and punches of dorsal striatum were immunoblotted for CaMKII Thr286 autophosphorylation as an index of CaMKII activation. KCl depolarization increased levels of CaMKII autophosphorylation ~2-fold; this increase was blocked by an LTCC antagonist and was mimicked by treatment with pharmacological LTCC activators. The chelation of extracellular calcium robustly decreased basal CaMKII autophosphorylation within 5min and increased levels of total CaMKII in cytosolic fractions, in addition to decreasing the phosphorylation of CaMKII sites in the GluN2B subunit of NMDA receptors and the GluA1 subunit of AMPA receptors. We also found that the maintenance of basal levels of CaMKII autophosphorylation requires low-voltage gated T-type calcium channels, but not LTCCs or R-type calcium channels. Our findings indicate that CaMKII activity is dynamically regulated by multiple calcium channels in the striatum thus coupling calcium entry to key downstream substrates.