Dynamic monitoring of PD-L1 and Ki67 in circulating tumor cells of metastatic non-small cell lung cancer patients treated with pembrolizumab.

Programmed cell death protein ligand-1 (PD-L1) expression in non-small cell lung cancer (NSCLC) tumors guides treatment selection. PD-L1 expression in circulating tumor cells (CTCs) may provide further information. We have explored PD-L1 and marker of proliferation Ki-67 (Ki67; also known as MKI67) in CTCs in longitudinal samples of 47 advanced NSCLC patients receiving pembrolizumab. A triple immunofluorescence, against cytokeratin, PD-L1, and Ki67, was performed on peripheral blood mononuclear cells, at baseline, post-first cycle, post-third, and primary resistance (PMR). Patients displaying PMR (progression at first evaluation) were classified as progressive disease (PD) and those with clinical benefit as disease control (DC). CTCs were categorized as PD-L1high/low/medium/negative and Ki67+ or Ki67- . CTC evaluation revealed a significant increase in the PD-L1low CTC rate at PMR compared to baseline (2.5% at baseline vs. 36.5% at PMR), whereas a reduction in the PD-L1high CTC rate was observed (31.5% vs. 0%, respectively). Investigation of CTC status between PD and DC patients showed that PD patients more frequently increased total and PD-L1low CTCs after first cycle compared to DC (83% of PD vs. 37% of DC and 67% of PD vs. 8% of DC, respectively). Progression-free survival (PFS) was longer in patients with decreased total and PD-L1low CTCs after first cycle compared to those with increased CTCs (median PFS: not reached vs. 2 months). PD-L1+ patients presenting a high Ki67 index (% Ki67+ CTCs > 30%) before treatment had a shorter PFS compared to those with a low Ki67 (≤ 30%), and overall survival (OS) was shorter in PD-L1+ patients harboring Ki67+ CTCs compared to those not presenting (median OS: 11.8 months vs. 33.1 months, respectively). In sequential samples of patients with a durable benefit, a low Ki67 index was observed. Our results suggest that monitoring PD-L1 and Ki67 expression in CTCs of NSCLC patients treated with pembrolizumab may be predictive for pembrolizumab efficacy.

Dynamic changes of CTCs in patients with metastatic HR(+)/HER2(-) breast cancer receiving salvage treatment with everolimus/exemestane.

PURPOSE: Detection of CTCs represents a poor prognostic factor in patients with early and metastatic breast cancer (mBC) and treatment with everolimus-exemestane (E/E) is an established effective treatment in hormone receptor-positive/HER2-negative mBC patients. The effect of E/E on CTCs in mBC patients was prospectively investigated. METHODS: CTCs from 50 pre-treated patients with mBC receiving E/E were analyzed using the CellSearch (CS) platform and triple immunofluorescence (IF) staining for cytokeratin, M30 and Ki67 expression to assess their proliferative and apoptotic status. RESULTS: CTCs (by CS) were detected in 64% of patients before treatment and E/E administration resulted in their decreased prevalence [(n = 18; 36%, p = 0.004) and (n = 7; 19.4%, p = 0.019) post-1st and post-3rd treatment cycle, respectively] whereas it was significantly increased at disease progression (PD: 61%) compared to post-1st and post-3rd cycle (p = 0.049 and p = 0.021, respectively). Ki67-positive CTCs were detected in 60%, 60%, 17% and 50% of patients before treatment, post-1st, post-3rd cycle and at PD, respectively, while the opposite was observed for M30-positive CTCs (0% at baseline, 10% after the 1st cycle, 50% after the 3rd cycle and 0% at PD). The detection of even ≥ 1 CTC/5 ml after one cycle was associated with decreased PFS (3.3 vs 9.0 months, p = 0.025) whereas the detection of even ≥ 2 CTCs at PD was associated with decreased OS (32.4 vs 19.5 months; p = 0.009). CONCLUSIONS: The combination of E/E resulted in early elimination of proliferating CTCs in mBC patients and this effect was associated with a favorable clinical outcome.

Circulating microRNAs in the early prediction of disease recurrence in primary breast cancer.

BACKGROUND: In primary breast cancer metastases frequently arise from a state of dormancy that may persist for extended periods of time. We investigated the efficacy of plasma micro-RNA (miR)-21, miR-23b, miR-190, miR-200b and miR-200c, related to dormancy and metastasis, to predict the outcome of patients with early breast cancer. METHODS: miRNAs were evaluated by RT-qPCR in plasma obtained before adjuvant chemotherapy. miRNA expression, classified as high or low according to median values, correlated with relapse and survival. Receiver operating characteristic (ROC) curves were constructed to determine miRNA sensitivity and specificity. RESULTS: miR-21 (p < 0.001), miR-23b (p = 0.028) and miR-200c (p < 0.001) expression were higher and miR-190 was lower (p = 0.013) in relapsed (n = 49), compared to non-relapsed patients (n = 84). Interestingly, miR-190 was lower (p = 0.0032) in patients with early relapse (at < 3 years; n = 23) compared to those without early relapse (n = 110). On the other hand, miR-21 and miR-200c were higher (p = 0.015 and p < 0.001, respectively) in patients with late relapse (relapse at ≥ 5 years; n = 20) as compared to non-relapsed patients. High miR-200c was associated with shorter disease-free survival (DFS) (p = 0.005) and high miR-21 with both shorter DFS and overall survival (OS) (p < 0.001 and p = 0.033, respectively) compared to low expression. ROC curve analysis revealed that miR-21, miR-23b, miR-190 and miR-200c discriminated relapsed from non-relapsed patients. A combination of of miR-21, miR-23b and miR-190 showed higher sensitivity and specificity in ROC analyses compared to each miRNA alone; accuracy was further improved by adding lymph node infiltration and tumor grade to the panel of three miRs (AUC 0.873). Furthermore, the combination of miR-200c, lymph node infiltration, tumor grade and estrogen receptor predicted late relapse (AUC 0.890). CONCLUSIONS: Circulating miRNAs are differentially expressed among relapsed and non-relapsed patients with early breast cancer and predict recurrence many years before its clinical detection. Our results suggest that miRNAs represent potential circulating biomarkers in early breast cancer.

Expression of insulin-like growth factor-1 receptor in circulating tumor cells of patients with breast cancer is associated with patient outcomes.

In patients with breast cancer, markers of aggressiveness such as dysregulation of the insulin-like growth factor receptor (IGF1R) system and E-cadherin loss are commonly observed. Reduced IGF1R expression is correlated with decreased E-cadherin levels and increased cell motility. We assessed IGF1R and E-cadherin expression in circulating tumor cells (CTCs) in patients with breast cancer. Peripheral blood mononuclear cells of early (n = 87)- and metastatic (n = 126)-stage breast cancer patients (obtained prior to adjuvant and first-line chemotherapy) were evaluated using double immunofluorescence (IF) staining for cytokeratin (CK) and IGF1R. Triple IF using CK, IGF1R, and E-cadherin antibodies was performed in selected CTC(+) patients. IGF1R(+) CTCs were more frequently observed in early disease than in metastatic disease (86% vs 68% of CTCs, P = 0.04) stage, whereas IGF1R(-) CTCs were more common in metastatic than in early disease (32% vs 14% of CTCs, P = 0.002). 100% of CTC(+) patients with early disease, compared to 79% of those with metastatic disease, harbored IGF1R(+) CTCs (P = 0.007). Patients with early disease and exclusively IGF1R(+) CTCs had longer disease-free (P = 0.02) and overall survival (P = 0.001) compared to patients with both IGF1R(+) and IGF1R(-) CTC populations. 67% of early-stage CTC(+) patients evaluated had exclusively IGF1R(+)/E-cadherin(+) CTCs, 33% also had IGF1R(-)/E-cadherin(-) CTCs, and none had exclusively IGF1R(-)/E-cadherin(-) CTCs compared to 17%, 75%, and 8% of metastatic patients, respectively (P = 0.027). Similarly, in paired samples of patients with early disease that progressed to metastatic disease, the proportion of IGF1R(+)/E-cadherin(+) CTCs was reduced and IGF1R(-)/E-cadherin(-) CTCs were increased in the metastatic stage compared to early disease stage. IGF1R(+) CTCs are commonly detected in breast cancer, and their frequency decreases in the metastatic disease stage. IGF1R(+)/E-cadherin(+) CTCs also decrease in metastatic patients. IGF1R(+) CTCs are associated with favorable outcomes in early disease stage, suggesting that IGF1R expression is correlated with reduced metastatic potential in breast cancer.

A Comparison of Three Methods for the Detection of Circulating Tumor Cells in Patients with Early and Metastatic Breast Cancer.

BACKGROUND: We directly compared CTC detection rates and prognostic significance, using three different methods in patients with breast cancer (BC). METHODS: Early (n=200) and metastatic (n=164) patients were evaluated before initiating adjuvant or first-line chemotherapy, using the CellSearchTM System, an RT-qPCR for CK-19 mRNA detection and by double immunofluorescence (IF) microscopy using A45-B/B3 and CD45 antibodies. RESULTS: Using the CellSearchTM System, 37% and 16.5% of early BC patients were CTC-positive (at ≥1 and ≥2 CTCs/23 ml of blood), 18.0% by RT-qPCR and 16.9% by IF; no agreement was observed between methods. By the CellSearchTM 34.8% and 53.7% (at≥ 5 and ≥ 2 CTCs/7.5 ml) of metastatic patients were CTC-positive, 37.8% by RT-qPCR and 28.5% by IF. A significant agreement existed only between the CellSearchTM and RT-qPCR. In 60.8% of cases, differential EpCAM and CK-19 expression on CTCs by IF could explain the discrepancies between the CellSearchTM and RT-qPCR. CTC-positivity by either method was associated with decreased overall survival in metastatic patients. CONCLUSION: A significant concordance was observed between the CellSearchTM and RT-qPCR in metastatic but not in early BC. Discordant results could be explained in part by CTC heterogeneity. CTC detection by all methods evaluated had prognostic relevance in metastatic patients.

Evaluation of proliferation and apoptosis markers in circulating tumor cells of women with early breast cancer who are candidates for tumor dormancy.

INTRODUCTION: Clinical dormancy is frequently observed in breast cancer. In the present study, we aimed to characterize circulating tumor cells (CTCs) in dormancy candidates (DC) with early breast cancer in terms of proliferation and apoptosis. METHODS: Cytospins of peripheral blood mononuclear cells (PBMCs) were obtained from DC (n = 122) who were disease-free for at least 5 years and from metastatic patients (n = 40) who relapsed more than 5 years after surgery. Sequential samples from eight DC (n = 36) who maintained a prolonged disease-free status and from eight DC (n = 27) presenting late relapse during follow-up, were also analyzed. PBMCs were triple stained with a pancytokeratin, antibody along with anti-Ki67 and anti-M30 antibodies as proliferation and apoptosis markers, respectively. RESULTS: CTCs were identified in 40 (33%) of 122 DC and in 15 (37.5%) of 40 metastatic patients. In total, twenty-five (62.5%) DC had exclusively dormant (Ki67(-)/M30(-)), seven (17.5%) had proliferative Ki67(+)/M30(-), four (10%) had apoptotic Ki67(-)/M30(+) and four (10%) had both phenotypes of proliferative and apoptotic CTCs. In comparison, 53.4% of CTC-positive metastatic patients had exclusively dormant and 46.6% had proliferative CTCs; none had apoptotic CTCs (P = 0.039). Among all CTCs detected in DC patients, 82.4% were dormant, whereas in the nondormant population, 32.5% were proliferative and 67.5% apoptotic. The respective percentages in metastatic patients were 59.1%, 100% and 0% (P <0.0001). Moreover, apoptotic CTCs prevailed among nondormant CTCs detected in sequential samples from DC who remained in a prolonged disease-free status compared to those presenting late relapse during follow-up (70.6% versus 43.5% (P = 0.0002)). CONCLUSIONS: The apoptotic index of CTCs is increased during clinical dormancy, whereas the proliferation index is increased on relapse. In addition, apoptotic CTCs are more frequently encountered during follow-up in DC patients who remain disease-free compared to those with subsequent late relapse, suggesting that monitoring proliferation and apoptosis in CTCs during clinical dormancy merits further investigation as a tool for predicting late disease recurrence.

Targeting the insulin-like growth factor I receptor inhibits proliferation and VEGF production of non-small cell lung cancer cells and enhances paclitaxel-mediated anti-tumor effect.

The effects of AVE1642, a human monoclonal antibody against IGF-IR, were examined in NSCLC cell lines in order to characterize its anti-proliferative and anti-angiogenic activity as a single agent and in combination with chemotherapy. AVE1642 inhibited IGF-IR signaling and suppressed IGF-I-induced, serum-stimulated or autocrine-mediated proliferation of NSCLC cells in vitro. Furthermore, the combination of paclitaxel and AVE1642 resulted in a sequence-dependent increase in the inhibition of cell proliferation, compared to each agent alone, which was associated with a dose-dependent increase in phosphorylated IGF-IR and Akt. Moreover, inhibition of IGF-IR signaling by AVE1642 reduced IGF-I-induced VEGF production by NSCLC cells as well as the migratory capacity of HUVEC cells challenged with conditioned media from lung cancer cells previously exposed to IGF-I. The above results suggest that inhibition of IGF-IR signaling by AVE1642 enhances the efficacy of chemotherapy and modulates VEGF and angiogenesis in NSCLC. These effects may have important clinical implications in the treatment of NSCLC.

Caveolin-1 regulates EGFR signaling in MCF-7 breast cancer cells and enhances gefitinib-induced tumor cell inhibition.

Caveolin-1, an essential protein constituent of caveolae, is involved in cell signaling through its association with various signaling molecules. Epidermal growth factor receptor (EGFR) interacts directly with caveolin-1 and this interaction functionally regulates EGFR tyrosine kinase activity. In this report we investigated the role of caveolin-1 overexpression on EGFR signaling in MCF-7 breast cancer cell line. We demonstrate here that although total EGFR expression levels are similar, EGFR phosphorylation is diminished in MCF-7/CAV1 cells compared to parental MCF-7 cells. In addition, MCF-7/CAV1 cells exhibit higher total and activated Akt levels. Moreover, MCF-7/CAV1 cells stimulated with EGF display higher EGFR and Akt phosphorylation associated with enhanced proliferative and motility rates, compared to MCF-7 cells. Pretreatment with gefitinib inhibits EGF-induced stimulation of both EGFR and downstream Akt and MAPK more efficiently in MCF-7/CAV1 than in MCF-7 cells. In accordance, EGF-induced proliferation and migration is more effectively suppressed with gefinitib in MCF-7/CAV1 compared to parental cells. In conclusion these results suggest that caveolin-1 overexpression in MCF-7 breast cancer cell line modulates EGFR activation levels and EGF-induced EGFR signalling. This is associated with enhanced antitumor effects of gefitinib suggesting a role for EGFR inhibition in caveolin-1 overexpressing breast cancers.

TAF7 (TAFII55) plays a role in the transcription activation by c-Jun.

c-Jun is a member of the AP-1 family of transcription factors regulating expression of specific target genes in a variety of cellular processes including proliferation, stress response, and tumorigenicity. In the present study we have analyzed the mechanism of c-Jun function as a transactivator with respect to members of the basal transcription machinery, TATA-binding protein-associated factors (TAFs). We show that one member of the family, human TAF7 (formerly TAFII55), physically interacts with c-Jun through two independent interaction domains, within the N- and C-terminal part of c-Jun. Interaction in vitro correlates with enhanced transactivation function of c-Jun in HEK293 and COS cells in the presence of increasing amounts of TAF7. TAF7 interacts preferentially with DNA-bound phosphorylated c-Jun, suggesting that TAF7 represents a novel c-Jun co-activator mediating activation of AP-1 target genes in response to extracellular signals.