Evaluation of CDCP1 (CD318) and endoglin (CD105) expression as prognostic markers in acute myeloid leukemia

BACKGROUND: The most commonly used prognostic factors in acute myeloid leukemia (AML) are cytogenetic, molecular, and morphological markers. However, AML prognosis is still unfavorable particularly in adults. So, further reliable markers are urgently needed to improve the risk stratification and treatment decisions. CUB domain-containing protein 1 (CDCP1; CD318) and endoglin (CD105) are new markers correlated with poor prognosis in different solid tumors, but their role in AML prognosis is not fully evaluated. OBJECTIVES: This work aimed to evaluate the prognostic role of CD318 and CD105 in AML and their impact on the outcomes. METHODS: Sixty-five newly diagnosed AML patients were included in this study. CD318 and CD105 expression was assessed by quantitative real-time polymerase chain reaction. Patients were followed up for ∼ 2 years to evaluate the prognostic impact of gene expression on the outcomes. RESULTS: Patients with high CD318 and CD105 showed higher white blood cell (WBC) count, M2 subtype, poor cytogenetic risk, reduced complete remission, and a greater number of deaths compared to low CD318 and CD105. CD318 was correlated with CD105, and both were correlated with WBC count, bone marrow blasts, and peripheral blood blasts. After a follow-up period of up to 24 months, relapse-free survival for high CD318 and CD105 was significantly different (42.1% and 52.6% vs. 64.5% and 58.1% for low CD318 and CD105, respectively). Survival was worse in patients with high CD318 and CD105, as the mean survival time was 13.9 and 13.3 months compared to 24 and 22.7 months in low CD318 and CD105, respectively. CONCLUSIONS: CD318 and CD105 are upregulated in AML patients. Their overexpression was associated with poor response to treatment and poor outcomes. Therefore, CD318 and CD105 can be useful prognostic markers in AML.

Differential expression of SCUBE2 in cancer of the vulva.

In these brief notes we document work using published microarray data (1, 2) to pioneer integrative transcriptome analysis comparing vulvar carcinoma to its tissue of origin, the vulva. We report the differential expression of signal peptide, CUB domain and EGF-like domain-containing 2, encoded by SCUBE2, in cancer of the vulva. SCUBE2 may be of pertinence to understanding transformation and disease progression in vulvar cancer (3).

CUB domain containing protein 1 (CDPC1) is a target for radioligand therapy in castration resistant prostate cancer

Purpose: Radioligand therapy (RLT) is relatively unexplored in metastatic castration resistant prostate cancer (mCRPC), with much of the focus having been on bone seeking radionuclides and PSMA-directed RLT. Herein, we evaluated if CUB domain containing protein 1 (CDCP1) can be exploited to treat mCRPC with RLT, particularly for subsets like small cell neuroendocrine prostate cancer (SCNC) that would not be expected to respond to current options. Experimental Design: CDCP1 mRNA levels were evaluated in the RNA-seq data from 119 recent mCRPC biopsies. Protein expression was assessed in twelve SCNC and adenocarcinoma patient derived xenografts. Saturation binding assays were performed with 4A06, a recombinant human antibody that targets the CDCP1 ectodomain. The feasibility of imaging and treating mCRPC in vivo was tested with 89Zr-4A06 and 177Lu-4A06. Results: CDCP1 mRNA expression was observed in over 90% of mCRPC biopsies, including SCNC and in adenocarcinoma with low FOLH1 (PSMA) levels. A modest anticorrelation was observed between CDCP1 and PTEN. Overall survival was not significantly different based on CDCP1 mRNA levels, regardless of PTEN status. Full length and/or cleaved CDCP1 was expressed in ten of twelve PDX samples . Bmax values of ~22,000 and ~6,200 fmol/mg were calculated for two human prostate cancer cell lines. Five prostate cancer models were readily detected in vivo with 89Zr-4A06. 177Lu-4A06 significantly suppressed the growth of DU145 tumors compared to control. Conclusions: The antitumor data and the overexpression of CDCP1 reported herein provide the first evidence promoting CDCP1 directed RLT as a treatment strategy for mCRPC.

Targeting a proteolytic neo-epitope of CUB-domain containing protein 1 in RAS-driven cancer

A central challenge for any therapeutic is targeting diseased over normal cells. Proteolysis is frequently upregulated in disease and can generate proteoforms with unique neo-epitopes. We hypothesize that targeting proteolytic neo-epitopes can enable more effective and safer treatments, reflecting a conditional layer of disease-specific regulation. Here, we characterized the precise proteolytic isoforms of CUB domain containing protein 1 (CDCP1), a protein overexpressed and specifically cleaved in RAS-driven cancers. We validated that the N-terminal and C-terminal fragments of CDCP1 remain associated after proteolysis in vitro and on the surface of pancreatic cancer cells. Using a differential phage display strategy, we generated exquisitely selective recombinant antibodies that target cells harboring cleaved CDCP1 and not the full-length form using antibody-drug conjugates or a bi-specific T-cell engagers. We show tumor-specific localization and anti-tumor activity in a syngeneic pancreatic tumor model having superior safety profiles compared to a pan-CDCP1-targeting antibody. Our studies show proteolytic neo-epitopes can provide an orthogonal AND gate for disease-specific targeting.

Over-expression of CUB domain containing protein 1 in human endometrial cancer.

Gynecologic cancers including cancers of the endometrium are a clinical problem (1-4). We mined published microarray data (5, 6) to discover genes associated with endometrial cancers by comparing transcriptomes of the normal endometrium and endometrial tumors from humans. We identified CUB domain containing protein 1, encoded by CDCP1, as among the most differentially expressed genes, transcriptome-wide, in cancers of the endometrium. CDCP1 was expressed at significantly higher levels in endometrial tumor tissues as compared to the endometrium. Importantly, in human endometrial cancer, primary tumor expression of CDCP1 was correlated with overall survival in endometrial cancer patients with Grade 2 tumors. CDCP1 may be a molecule of interest in understanding the etiology or progression of human endometrial cancer.

Protective Effect of SCUBE1 on Oxidative Stress-induced Apoptosis in Human Ovarian Granulosa Cells

Background: Apoptosis of ovarian granulosa cells (GCs) is a sign of follicular atresia. This study aimed to explore the role and mechanism of signal peptide, CUB domain, epidermal growth factor-like protein1 (SCUBE1) in protecting GCs from apoptosis induced by hydrogen peroxide (H2O2). Results: SCUBE1 was expressed in women of all ages and had the highest expression level in the ovaries in multiple organs and tissues of KM mouse. In vitro cell experiments show that SCUBE1 pretreatment reduced H2O2-induced apoptosis and improved cell viability. SCUBE1 also blocked the production of ROS in cells and improved mitochondrial membrane potential. After SCUBE1 pretreatment, anti-apoptotic protein Bcl-2 expression was upregulated, whereas the expression of the pro-apoptotic proteins Bax, Bax/Bcl-2, Caspase-3, and p53 were downregulated. Analysis of the impact of SCUBE1 (c.1169C >G, p.P390R) mutation from the aspect of mutation pathogenicity; protein stability; and gene haplotype insufficiency, indicated that the p.P390R mutation is significantly pathogenic.Conclusions: This is the first time that the potential role of SCUBE1 in protecting GCs from H2O2-induced damage by blocking the production of ROS, increasing the mitochondrial membrane potential and regulating apoptosis-related proteins, attributing to POI, is studied. SCUBE1 (c.1169C >G, p.P390R) mutation has significant pathogenicity but the specific harm needs to be confirmed by further studies.

Crystal structure of ADAMTS13 CUB domains reveals their role in global latency

ADAMTS13 is a plasma metalloprotease that is essential for the regulation of von Willebrand factor (VWF) function, mediator of platelet recruitment to sites of blood vessel damage. ADAMTS13 function is dynamically regulated by structural changes induced by VWF binding that convert it from a latent to active conformation. ADAMTS13 global latency is manifest by the interaction of its C-terminal CUB1-2 domains with its central Spacer domain. We resolved the crystal structure of the ADAMTS13 CUB1-2 domains revealing a previously unreported configuration for the tandem CUB domains. Docking simulations between the CUB1-2 domains with the Spacer domain in combination with enzyme kinetic functional characterization of ADAMTS13 CUB domain mutants enabled the mapping of the CUB1-2 domain site that binds the Spacer domain. Together, these data reveal the molecular basis of the ADAMTS13 Spacer-CUB interaction and the control of ADAMTS13 global latency.

CDCP1 promotes compensatory renal growth by integrating Src and Met signaling

Compensatory growth of organs after loss of their mass and/or function is controlled by hepatocyte growth factor (HGF), but the underlying regulatory mechanisms remain elusive. Here, we show that CUB domain-containing protein 1 (CDCP1) promotes HGF-induced compensatory renal growth. Using canine kidney cells as a model of renal tubules, we found that HGF-induced temporal up-regulation of Src activity and its scaffold protein, CDCP1, and that the ablation of CDCP1 robustly abrogated HGF-induced phenotypic changes, such as morphological changes and cell growth/proliferation. Mechanistic analyses revealed that up-regulated CDCP1 recruits Src into lipid rafts to activate STAT3 associated with the HGF receptor Met, and activated STAT3 induces the expression of matrix metalloproteinases and mitogenic factors. After unilateral nephrectomy in mice, the Met-STAT3 signaling is transiently up-regulated in the renal tubules of the remaining kidney, whereas CDCP1 ablation attenuates regenerative signaling and significantly suppresses compensatory growth. These findings demonstrate that CDCP1 plays a crucial role in controlling compensatory renal growth by focally and temporally integrating Src and Met signaling.