Abstract Background: Human epidermal growth factor receptor 2 (HER2)-positive breast cancer accounts for 20-30% of breast carcinomas and is associated with a poor prognosis. While anti-HER2 targeted therapies have improved outcomes within this group, a subset of these tumors eventually develop resistance urgently requiring novel therapeutic options. In addition to classic HER2+ subtype, estrogen receptor (ER)-positive and HER2-positive tumors (luminal B) are another subtype of HER2 expressing breast carcinomas which could also benefit from additional therapies. Targeting the androgen receptor (AR) pathway and the PD-L1 axis may represent potential new therapeutic strategies in breast cancer. Our group previously reported that AR expression is seen in ¾ of HER2+ carcinomas and is more common in luminal B compared to classic HER2+ tumors. In this report, we evaluated expression of PD-L1 in tumor infiltrating lymphocytes (TILs) in both classic HER2 + and Luminal B subtypes of breast carcinomas and correlated the expression of PD-L1 with AR expression in these tumors. Methods: The study population consisted of 114 patients with HER2-positive invasive breast carcinoma diagnosed from 2009-2014 at Northwestern Memorial Hospital. Electronic medical records were reviewed for patient demographics (mean age 54, range 23-80). Pathologic tumor characteristics (histologic type, size, and grade) and tumor marker profile (ER and HER2) were evaluated. Tissue microarrays were constructed (3 cores from each case to account for tumor heterogeneity) for immunohistochemical evaluation of AR and PD-L1. AR was graded as positive when at least 1% of tumor cells showed nuclear immunoreactivity. For PD-L1, the extent of staining (0%=0, 1-10%=1, 11-50%=2, and 51-100%=3) and staining intensity (0, 1+, 2+, 3+) were assessed in TILs. Then a composite score (CS) was calculated by multiplying extent and intensity results (range 0-9; 0-3=negative, 4-9=positive). Results: Of the 114 studied breast carcinoma cases, 54 were classic HER2+ tumors (47%) and 60 were luminal B (53%) tumors. Approximately 69% of classic HER2+ and 87% of luminal B cases were positive for AR. Of interest, in classic HER2+ cases, the expression of PD-L1 in TILs was inversely correlated with the expression of AR, with 82% (14/17) of AR- tumors being positive for PD-L1 in TILs compared to only 46% (17/37) of AR+ tumors with PD-L1 expression in TILs (p<0.01). No association of expression of PD-L1 in TILs with AR expression was observed in luminal B cases (62% in AR+ versus 50% in AR- tumors; p=0.70). Moreover, in classic HER2+/AR- group, grade 3 tumors were seen almost exclusively in the PD-L1 expressing group (13 versus 3), in contrast to the equal number of grade 3 tumors in classic HER2+/AR+ group regardless of PD-L1 expression in TILs (14 versus 14). No association of the PD-L1 expression with age, race, and tumor histologic types was observed in classic HER2+/AR+ or classic HER2+/AR- cases. Conclusions: Our results demonstrated that the expression of PD-L1 in TILs was inversely correlated with the expression of AR in classic HER2 positive tumors but not in luminal B tumors. We also found that in classic HER2+/AR- group, grade 3 tumors were seen almost exclusively in the PD-L1 expression group. Our findings add to the body of knowledge of the molecular mechanisms that drive the different molecular subtypes of breast carcinomas and raise the interesting possibility that new treatment strategies such as targeting the PD-L1 axis may show more benefit against the AR negative subtype of the classic HER2 positive carcinomas. Citation Format: Tiansheng Shen, Jennifer L. Pincus, Kalliopi P. Siziopikou. PD-L1 expression in tumor infiltrating lymphocytes (TILs) inversely correlates with androgen receptor (AR) expression in HER2-positive breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-10-30.
Recent studies have suggested that neuropeptides could play previously unrecognized functional roles in peripheral gustation. To date, two peptides, cholecystokinin and vasoactive intestinal peptide, have been localized to subsets of taste-bud (TB) cells (TBC) and one, cholecystokinin, has been demonstrated to produce excitatory physiological actions. This study extends our knowledge of neuropeptides in TBC in three significant ways. First, using techniques of immunocytochemistry and RT-PCR, evidence is presented for the expression of a third peptide, neuropeptide Y (NPY). Like other peptide expression patterns, NPY expression is circumscribed to a subset of cells within the taste bud. Second, using physiological studies, we demonstrate that NPY specifically enhances an inwardly rectifying potassium current via NPY-Y1 receptors. This action is antagonistic to the previously demonstrated inhibitory effect exerted by cholecystokinin on the same current, thus providing important clues to their signaling roles in the TB. Third, using the technique of double-labeled fluorescent immunocytochemistry, the relationship of three subsets of neuropeptide-expressing TB cells to one another was examined. Remarkably, NPY expressions, although fewer in number than either the cholecystokinin or vasoactive intestinal peptide subsets, overlapped 100% with either peptide. Collectively, these three observations transform previously suggestive roles of neuromodulation by peptides in TB cells to more concrete signaling pathways. The extensive colocalization of these peptides suggests they may be subject to similar presynaptic influences of release yet have antagonistic postsynaptic actions. The convergence or divergence of these postsynaptic actions awaits further investigation.
The transcription factor NFAT5 is a key regulator in protection from hypertonic stress in the renal medulla but its role in skeletal muscle has not been examined. Since hypertonic stress occurs during hyperglycemic crisis in patients with diabetes, we sought to evaluate the effects of sustained (1–2 days) and elevated glucose (25–50 mM) on endogenous NFAT5 activity and Ca2+ signaling in skeletal muscle fibers in culture. Exposure to high glucose increased NFAT5 nuclear translocation and its expression. NFAT-driven luciferase assays demonstrated an increase in transcriptional activity in fibers exposed to sustained high glucose. These effects were insensitive to the inhibition of calcineurin A, but were sensitive to both p38α MAPK and PIKK inhibition. Elevated glucose also upregulated the expression of aldose reductase and sodium/myo-inositol transporter. Ca2+ imaging techniques revealed larger and abnormal double Ca2+ transients upon a single 1 ms field stimulus in the majority of fibers challenged with elevated glucose. The transverse tubule morphology was also disrupted in fibers exposed to high glucose. In conclusion, elevated extracellular glucose resulted in increased NFAT5 expression and transcriptional activity and caused osmoregulatory responses in parallel with abnormal Ca2+ signaling in skeletal muscle. These changes may play a role in the pathophysiology of acute hyperglycemic episodes.
To analyze the expression of E-cadherin and β-catenin in triple-negative breast cancer (TNBC) to assess their prognostic significance.The expression of E-cadherin and β-catenin was examined semiquantitatively and correlated with other pathologic factors and survival outcomes.Of 72 consecutive TNBCs, 56% showed reduced membranous expression of E-cadherin or β-catenin, with a strong correlation to each other. Of the clinicopathologic factors analyzed, tumor size and nodal status were significantly associated with overall survival and disease-specific survival, while the latter remained an independent factor by multivariate analysis. Reduced E-cadherin and β-catenin were both significantly associated with a poor overall survival and disease-specific survival by univariate and multivariate analyses.E-cadherin and β-catenin expression provides discriminative prognostic power independent of conventional pathologic factors, thus further reinforcing the important role of cell adhesion molecules in the process of tumor metastasis, especially in TNBC.
