Olink and gut microbial metabolomics reveal new biomarkers for the prediction and diagnosis of PMOP.

LNTRODUCTION: Postmenopausal osteoporosis (PMOP) can cause postmenopausal women to experience pain and interference. Identifying and exploring potential early diagnostic biomarkers of PMOP is of substantial clinical value and social significance. This study aimed to screen for potential novel diagnostic biomarkers of PMOP through a multiomics approach, providing new directions and ideas for the early prevention and treatment of this disease. MATERIALS AND METHODS: Fifteen postmenopausal women with osteoporosis and 12 without were recruited. Clinical information was collected, and various clinical biochemical parameters were tested. Plasma and fecal samples were collected and analyzed using Olink proteomics and gut microbial metabolomics. RESULTS: The functions of the differentially abundant metabolites were mainly related to autophagy and arginine and proline metabolism and were involved in immunoinflammatory metabolic processes. Olink showed significant differences in the expression of seven inflammation-related proteins between the two groups. CONCLUSION: We demonstrated that metabolic differences between PMOP patients and healthy controls were associated with inflammatory responses and found seven proteins with significant differences. Among these proteins, CDCP1, IL10, and IL-1alpha combined with clinical indicators had high discriminant efficiency in identifying PMOP. This is also the first study to demonstrate noteworthy changes in CDCP1 levels in patients with PMOP.

Detection and Isolation of Circulating Tumor Cells from Breast Cancer Patients Using CUB Domain-Containing Protein 1.

In cancer metastasis, single circulating tumor cells (CTCs) in the blood and disseminated tumor cells (DTCs) in the bone marrow mediate cancer metastasis. Because suitable biomarker proteins are lacking, CTCs and DTCs with mesenchymal attributes are difficult to isolate from the bulk of normal blood cells. To establish a procedure allowing the isolation of such cells, we analyzed the cell line BC-M1 established from DTCs in the bone marrow of a breast cancer patient by stable isotope labeling by amino acids in cell culture (SILAC) and mass spectrometry. We found high levels of the transmembrane protein CUB domain-containing protein 1 (CDCP1) in breast cancer cell lines with mesenchymal attributes. Peripheral blood mononuclear cells were virtually negative for CDCP1. Confirmation in vivo by CellSearch revealed CDCP1-positive CTCs in 8 of 30 analyzed breast cancer patients. Only EpCam-positive CTCs were enriched by CellSearch. Using the extracellular domain of CDCP1, we established a magnetic-activated cell sorting (MACS) approach enabling also the enrichment of EpCam-negative CTCs. Thus, our approach is particularly suited for the isolation of mesenchymal CTCs with downregulated epithelial cancer that occur, for example, in triple-negative breast cancer patients who are prone to therapy failure.

SRC kinase activator CDCP1 promotes hepatocyte growth factor-induced cell migration/invasion of a subset of breast cancer cells.

Cancer invasion and metastasis are the major causes of cancer patient mortality. Various growth factors, including hepatocyte growth factor (HGF), are known to promote cancer invasion and metastasis, but the regulatory mechanisms involved are not fully understood. Here, we show that HGF-promoted migration and invasion of breast cancer cells are regulated by CUB domain-containing protein 1 (CDCP1), a transmembrane activator of SRC kinase. In metastatic human breast cancer cell line MDA-MB-231, which highly expresses the HGF receptor MET and CDCP1, we show that CDCP1 knockdown attenuated HGF-induced MET activation, followed by suppression of lamellipodia formation and cell migration/invasion. In contrast, in the low invasive/nonmetastatic breast cancer cell line T47D, which had no detectable MET and CDCP1 expression, ectopic MET expression stimulated the HGF-dependent activation of invasive activity, and concomitant CDCP1 expression activated SRC and further promoted invasive activity. In these cells, CDCP1 expression dramatically activated HGF-induced membrane remodeling, which was accompanied by activation of the small GTPase Rac1. Analysis of guanine nucleotide exchange factors revealed that ARHGEF7 was specifically required for CDCP1-dependent induction of HGF-induced invasive ability. Furthermore, immunofluorescence staining demonstrated that CDCP1 coaccumulated with ARHGEF7. Finally, we confirmed that the CDCP1-SRC axis was also crucial for HGF and ARHGEF7-RAC1 signaling in MDA-MB-231 cells. Altogether, these results demonstrate that the CDCP1-SRC-ARHGEF7-RAC1 pathway plays an important role in the HGF-induced invasion of a subset of breast cancer cells.

The roles of proteases in prostate cancer.

Since the proposition of the pro-invasive activity of proteolytic enzymes over 70 years ago, several roles for proteases in cancer progression have been established. About half of the 473 active human proteases are expressed in the prostate and many of the most well-characterized members of this enzyme family are regulated by androgens, hormones essential for development of prostate cancer. Most notably, several kallikrein-related peptidases, including KLK3 (prostate-specific antigen, PSA), the most well-known prostate cancer marker, and type II transmembrane serine proteases, such as TMPRSS2 and matriptase, have been extensively studied and found to promote prostate cancer progression. Recent findings also suggest a critical role for proteases in the development of advanced and aggressive castration-resistant prostate cancer (CRPC). Perhaps the most intriguing evidence for this role comes from studies showing that the protease-activated transmembrane proteins, Notch and CDCP1, are associated with the development of CRPC. Here, we review the roles of proteases in prostate cancer, with a special focus on their regulation by androgens.

CD6 and Its Interacting Partners: Newcomers to the Block of Cancer Immunotherapies.

Cancer management still requires more potent and safer treatments, of which immunomodulatory receptors on the lymphocyte surface have started to show promise in new cancer immunotherapies (e.g., CTLA-4 and PD-1). CD6 is a signal-transducing transmembrane receptor, mainly expressed by all T cells and some B and NK cell subsets, whose endogenous ligands (CD166/ALCAM, CD318/CDCP-1, Galectins 1 and 3) are overexpressed by malignant cells of different lineages. This places CD6 as a potential target for novel therapies against haematological and non-haematological malignancies. Recent experimental evidence for the role of CD6 in cancer immunotherapies is summarised in this review, dealing with diverse and innovative strategies from the classical use of monoclonal antibodies to soluble recombinant decoys or the adoptive transfer of immune cells engineered with chimeric antigen receptors.

Molecular mechanism by which CDCP1 promotes proneural-mesenchymal transformation in primary glioblastoma.

BACKGROUND: Compared with the proneural (PN) subtype of glioblastoma (GBM), the mesenchymal (MES) subtype is more invasive and immune evasive and is closely related to poor prognosis. Here, we used transcriptome data and experimental evidence to indicate that CUB domain-containing protein 1 (CDCP1) is a novel regulator that facilitates the transformation of PN-GBM to MES-GBM. METHODS: The mRNA expression data of CDCP1 in glioma were collected from the TCGA, CGGA and GEO databases, and in vitro experiments verified CDCP1 expression in glioma tissue samples. Independent prognostic analysis revealed the correlation of the CDCP1 expression level and patient survival. Bioinformatics analysis and experiments verified the biological function of CDCP1. Multivariate proportional hazards models and a PPI network were used to select key genes. A prognostic risk model for predicting the survival of glioma patients was constructed based on the selected genes. RESULTS: The results showed that the expression of CDCP1 increased with increasing tumor grade and that the overexpression of CDCP1 correlated with a poor prognosis. CDCP1 was highly expressed in MES-GBM but weakly expressed in PN-GBM. The risk model (considering CDCP1 combined with CD44 and ITGAM expression) could represent a tool for predicting survival and prognosis in glioma patients. CONCLUSIONS: Our study indicates that CDCP1 plays an important role in facilitating the transformation of PN-GBM to MES-GBM.

Preclinical Evaluation of a Fluorescent Probe Targeting Receptor CDCP1 for Identification of Ovarian Cancer.

Optimal cytoreduction for ovarian cancer is often challenging because of aggressive tumor biology and advanced stage. It is a critical issue since the extent of residual disease after surgery is the key predictor of ovarian cancer patient survival. For a limited number of cancers, fluorescence-guided surgery has emerged as an effective aid for tumor delineation and effective cytoreduction. The intravenously administered fluorescent agent, most commonly indocyanine green (ICG), accumulates preferentially in tumors, which are visualized under a fluorescent light source to aid surgery. Insufficient tumor specificity has limited the broad application of these agents in surgical oncology including for ovarian cancer. In this study, we developed a novel tumor-selective fluorescent agent by chemically linking ICG to mouse monoclonal antibody 10D7 that specifically recognizes an ovarian cancer-enriched cell surface receptor, CUB-domain-containing protein 1 (CDCP1). 10D7ICG has high affinity for purified recombinant CDCP1 and CDCP1 that is located on the surface of ovarian cancer cells in vitro and in vivo. Our results show that intravenously administered 10D7ICG accumulates preferentially in ovarian cancer, permitting visualization of xenograft tumors in mice. The data suggest CDCP1 as a rational target for tumor-specific fluorescence-guided surgery for ovarian cancer.

Identification of CD318 (CDCP1) as novel prognostic marker in AML.

Genetic and morphological markers are well-established prognostic factors in acute myeloid leukemia (AML). However, further reliable markers are urgently needed to improve risk stratification in AML. CD318 (CDCP1) is a transmembrane protein which in solid tumors promotes formation of metastasis and correlates with poor survival. Despite its broad expression on hematological precursor cells, its prognostic significance in hematological malignancies so far remains unclear. Here, we evaluated the role of CD318 as novel prognostic marker in AML by immunophenotyping of leukemic blasts. Flow cytometric evaluation of CD318 on leukemic cells in 70 AML patients revealed a substantial expression in 40/70 (57%) of all cases. CD318 surface levels were significantly correlated with overall survival in patients receiving anthracycline-based induction therapy or best available alternative therapy. Using receiver-operating characteristics, we established a cut-off value to define CD318lo and CD318hi expression in both cohorts. Notably, high CD318 expression correlated inversely as prognostic marker in both treatment cohorts: as poor prognostic marker in patients receiving intense therapy, whereas upon palliative care it correlated with better outcome. In conclusion, FACS-based determination of CD318 expression may serve as novel prognostic factor depending on implemented therapy in AML patients.

CUB domain-containing protein 1 (CDCP1) binds transforming growth factor beta family members and increase TGF-ß1 signaling pathway.

CUB domains are most exclusively found in secreted proteins and in a few transmembrane proteins. These domains are approximately 110 amino acids long and have four conserved cysteines that form a ß-sandwich fold. CUB domains proteins are involved in a wide range of biological functions. We have shown that CUB domains from Tolloid/BMP1 can bind BMP4 and block BMP signaling in the developing frog embryo. CUB domain-containing protein 1 (CDCP1) is one of the few transmembrane glycoprotein that contains three extracellular CUB domains and regulates anchorage-independent growth and cancer cell migration through activation of Src kinases. In the extracellular space, only a few proteins were found to interact with CDCP1 and at the moment no ligand was found. We demonstrate by using real time protein interaction on BIAcore chip that CDCP1 CUB domains bind directly to TGF-ß1 and BMP4. CDCP1 enhances TGF-ß1 signaling reporter activity and phosphorylated Smad2 levels but does not modulate BMP signaling pathway. CDCP1 actions on TGF-ß/Smad2 signaling are dependent on Smad2 and TGFRI and do not require Src or PKCδ binding. Our findings uncover a new co-receptor for TGF-ß1 and bring up new questions on whether CDCP1 cooperates with TGF-ß1 to promote cancer progression.

CDCP1 drives triple-negative breast cancer metastasis through reduction of lipid-droplet abundance and stimulation of fatty acid oxidation.

Triple-negative breast cancer (TNBC) is notoriously aggressive with high metastatic potential, which has recently been linked to high rates of fatty acid oxidation (FAO). Here we report the mechanism of lipid metabolism dysregulation in TNBC through the prometastatic protein, CUB-domain containing protein 1 (CDCP1). We show that a "low-lipid" phenotype is characteristic of breast cancer cells compared with normal breast epithelial cells and negatively correlates with invasiveness in 3D culture. Using coherent anti-Stokes Raman scattering and two-photon excited fluorescence microscopy, we show that CDCP1 depletes lipids from cytoplasmic lipid droplets (LDs) through reduced acyl-CoA production and increased lipid utilization in the mitochondria through FAO, fueling oxidative phosphorylation. These findings are supported by CDCP1's interaction with and inhibition of acyl CoA-synthetase ligase (ACSL) activity. Importantly, CDCP1 knockdown increases LD abundance and reduces TNBC 2D migration in vitro, which can be partially rescued by the ACSL inhibitor, Triacsin C. Furthermore, CDCP1 knockdown reduced 3D invasion, which can be rescued by ACSL3 co-knockdown. In vivo, inhibiting CDCP1 activity with an engineered blocking fragment (extracellular portion of cleaved CDCP1) lead to increased LD abundance in primary tumors, decreased metastasis, and increased ACSL activity in two animal models of TNBC. Finally, TNBC lung metastases have lower LD abundance than their corresponding primary tumors, indicating that LD abundance in primary tumor might serve as a prognostic marker for metastatic potential. Our studies have important implications for the development of TNBC therapeutics to specifically block CDCP1-driven FAO and oxidative phosphorylation, which contribute to TNBC migration and metastasis.

Evidence that cell surface localization of serine protease activity facilitates cleavage of the protease activated receptor CDCP1.

The cellular receptor CUB domain containing protein 1 (CDCP1) is commonly elevated and functionally important in a range of cancers. CDCP1 is cleaved by serine proteases at adjacent sites, arginine 368 (R368) and lysine 369 (K369), which induces cell migration in vitro and metastasis in vivo. We demonstrate that membrane localization of serine protease activity increases efficacy of cleavage of CDCP1, and that both secreted and membrane anchored serine proteases can have distinct preferences for cleaving at CDCP1-R368 and CDCP1-K369. Approaches that disrupt membrane localization of CDCP1 cleaving serine proteases may interfere with the cancer promoting effects of CDCP1 proteolysis.

The PDGFRß/ERK1/2 pathway regulates CDCP1 expression in triple-negative breast cancer.

BACKGROUND: CDCP1, a transmembrane protein with tumor pro-metastatic activity, was recently identified as a prognostic marker in TNBC, the most aggressive breast cancer subtype still lacking an effective molecular targeted therapy. The mechanisms driving CDCP1 over-expression are not fully understood, although several stimuli derived from tumor microenvironment, such as factors present in Wound Healing Fluids (WHFs), reportedly increase CDCP1 levels. METHODS: The expression of CDCP1, PDGFRß and ERK1/2cell was tested by Western blot after stimulation of MDA-MB-231 cells with PDGF-BB and, similarly, in presence or not of ERK1/2 inhibitor in a panel of TNBC cell lines. Knock-down of PDGFRß was established in MDA-MB-231 cells to detect CDCP1 upon WHF treatment. Immunohistochemical staining was used to detect the expression of CDCP1 and PDGFRß in TNBC clinical samples. RESULTS: We discovered that PDGF-BB-mediated activation of PDGFRß increases CDCP1 protein expression through the downstream activation of ERK1/2. Inhibition of ERK1/2 activity reduced per se CDCP1 expression, evidence strengthening its role in CDCP1 expression regulation. Knock-down of PDGFRß in TNBC cells impaired CDCP1 increase induced by WHF treatment, highlighting the role if this receptor as a central player of the WHF-mediated CDCP1 induction. A significant association between CDCP1 and PDGFRß immunohistochemical staining was observed in TNBC specimens, independently of CDCP1 gene gain, thus corroborating the relevance of the PDGF-BB/PDGFRß axis in the modulation of CDCP1 expression. CONCLUSION: We have identified PDGF-BB/PDGFRß-mediated pathway as a novel player in the regulation of CDCP1 in TNCBs through ERK1/2 activation. Our results provide the basis for the potential use of PDGFRß and ERK1/2 inhibitors in targeting the aggressive features of CDCP1-positive TNBCs.

Novel small molecule inhibiting CDCP1-PKCδ pathway reduces tumor metastasis and proliferation.

CUB domain-containing protein-1 (CDCP1) is a trans-membrane protein predominantly expressed in various cancer cells and involved in tumor progression. CDCP1 is phosphorylated at tyrosine residues in the intracellular domain by Src family kinases and recruits PKCδ to the plasma membrane through tyrosine phosphorylation-dependent association with the C2 domain of PKCδ, which in turn induces a survival signal in an anchorage-independent condition. In this study, we used our cell-free screening system to identify a small compound, glycoconjugated palladium complex (Pd-Oqn), which significantly inhibited the interaction between the C2 domain of PKCδ and phosphorylated CDCP1. Immunoprecipitation assays demonstrated that Pd-Oqn hindered the intercellular interaction of phosphorylated CDCP1 with PKCδ and also suppressed the phosphorylation of PKCδ but not that of ERK or AKT. In addition, Pd-Oqn inhibited the colony formation of gastric adenocarcinoma 44As3 cells in soft agar as well as their invasion. In mouse models, Pd-Oqn markedly reduced the peritoneal dissemination of gastric adenocarcinoma cells and the tumor growth of pancreatic cancer orthotopic xenografts. These results suggest that the novel compound Pd-Oqn reduces tumor metastasis and growth by inhibiting the association between CDCP1 and PKCδ, thus potentially representing a promising candidate among therapeutic reagents targeting protein-protein interaction.

CUB domain-containing protein 1 and the epidermal growth factor receptor cooperate to induce cell detachment.

BACKGROUND: While localized malignancies often respond to available therapies, most disseminated cancers are refractory. Novel approaches, therefore, are needed for the treatment of metastatic disease. CUB domain-containing protein1 (CDCP1) plays an important role in metastasis and drug resistance; the mechanism however, is poorly understood. METHODS: Breast cancer cell lines were engineered to stably express EGFR, CDCP1 or phosphorylation site mutants of CDCP1. These cell lines were used for immunoblot analysis or affinity purification followed by immunoblot analysis to assess protein phosphorylation and/or protein complex formation with CDCP1. Kinase activity was evaluated using phosphorylation site-specific antibodies and immunoblot analysis in in vitro kinase assays. Protein band excision and mass spectrometry was utilized to further identify proteins complexed with CDCP1 or ΔCDCP1, which is a mimetic of the cleaved form of CDCP1. Cell detachment was assessed using cell counting. RESULTS: This paper reports that CDCP1 forms ternary protein complexes with Src and EGFR, facilitating Src activation and Src-dependent EGFR transactivation. Importantly, we have discovered that a class of compounds termed Disulfide bond Disrupting Agents (DDAs) blocks CDCP1/EGFR/Src ternary complex formation and downstream signaling. CDCP1 and EGFR cooperate to induce detachment of breast cancer cells from the substratum and to disrupt adherens junctions. Analysis of CDCP1-containing complexes using proteomics techniques reveals that CDCP1 associates with several proteins involved in cell adhesion, including adherens junction and desmosomal cadherins, and cytoskeletal elements. CONCLUSIONS: Together, these results suggest that CDCP1 may facilitate loss of adhesion by promoting activation of EGFR and Src at sites of cell-cell and cell-substratum contact.

HIF-2α regulates CDCP1 to promote PKCδ-mediated migration in hepatocellular carcinoma.

Overexpression of CUB domain-containing protein 1 (CDCP1), a transmembrane glycoprotein and major substrate of Src family kinases (SFKs), always indicates unfavorable outcomes in various cancers. The characteristics of CDCP1 in hepatocellular carcinoma (HCC) have not been assessed. Most recently, CDCP1 was identified as a specific target gene of HIF-2α in clear cell renal carcinoma (CC-RCC). However, considering the role of HIF-2α in the progression of HCC is highly controversial, it is necessary to figure out whether HIF-2α and CDCP1 play a significant part in the metastasis of HCC. Our results showed that HIF-2α and CDCP1 were both induced by hypoxia, and the activation of CDCP1 was HIF-2α dependent. CDCP1 was governed by HIF-2α at mRNA and protein levels in HCC cell lines. Moreover, knocking down of HIF-2α not only inhibited cell invasion but also impaired the expression of Tyr(311) phosphorylation of protein kinase Cδ (PKCδ) which is a downstream factor of CDCP1 and has been reported to induce malignant migration in various tumors. Analysis of human HCC samples showed a negative correlation of CDCP1 expression with disease-free survival, and CDCP1 was an independent prognostic factors of disease-free survival. Taken together, these data demonstrated that HIF-2α could promote HCC cell migration by regulating CDCP1, and targeting HIF-2α-CDCP1-PKCδ pathway might be effective to inhibit HCC metastasis.

Quantitative Membrane Proteomics for Discovery of Actionable Drug Targets at the Surface of RAS-Driven Human Cancer Cells.

With the advent of promising lung cancer immunotherapies targeting proteins at the cell surface of RAS-driven human cancers, the mass spectrometry (MS)-based surfaceomics remains a feasible strategy for therapeutic target discovery. This chapter describes a protocol for discovery of druggable protein targets at the surface of RAS-driven human cancer cells. This method relies on bottom-up MS-based quantitative surfaceomics that employs in parallel, targeted hydrazide-based cell-surface glycoproteomics and global shotgun membrane proteomics to enable unbiased quantitative profiling of thousands of cell surface membrane proteins. A large-scale molecular map of the KRASG12V surface was attained, resulting in confident detection and quantitation of more than 500 cell surface membrane proteins that were found to be unique or upregulated at the surface of cells harboring the KRASG12V mutant. A multistep bioinformatic progression revealed a subset of unique and/or significantly upregulated proteins as priority drug targets selected for orthogonal cross-validation using immunofluorescence, structured illumination microscopy, and western blotting. Among cross-validated targets, CUB domain containing protein 1 (CDCP1) and basigin (BSG-CD147) were selected as leading targets due to their involvement in cell adhesion and migration, consistent with the KRASG12V malignant phenotype as revealed by scanning electron microscopy and phenotypic cancer cell assays. Follow-up studies confirmed CDCP1 as an actionable therapeutic target, resulting in development of recombinant antibodies capable of killing KRAS-transformed cancer cells in preclinical setting. The present MS-based surfaceomics workflow represents a powerful drug target discovery platform that enables development of innovative immunotherapeutics (e.g., antibody drug conjugate against CDCP1) for attacking oncogenic RAS-driven cancers at the cell surface.

Ascites-derived CDCP1+ extracellular vesicles subcluster as a novel biomarker and therapeutic target for ovarian cancer.

Introduction: Ovarian cancer (OVCA) is one of the most prevalent malignant tumors of the female reproductive system, and its diagnosis is typically accompanied by the production of ascites. Although liquid biopsy has been widely implemented recently, the diagnosis or prognosis of OVCA based on liquid biopsy remains the primary emphasis. Methods: In this study, using proximity barcoding assay, a technique for analyzing the surface proteins on single extracellular vesicles (EVs). For validation, serum and ascites samples from patients with epithelial ovarian cancer (EOC) were collected, and their levels of CDCP1 was determined by enzyme-linked immunosorbent assay. Tissue chips were prepared to analyze the relationship between different expression levels of CDCP1 and the prognosis of ovarian cancer patients. Results: We discovered that the CUB domain-containing protein 1+ (CDCP1+) EVs subcluster was higher in the ascites of OVCA patients compared to benign ascites. At the same time, the level of CDCP1 was considerably elevated in the ascites of OVCA patients. The overall survival and disease-free survival of the group with high CDCP1 expression in EOC were significantly lower than those of the group with low expression. In addition, the receiver operating characteristic curve demonstrates that EVs-derived CDCP1 was a biomarker of early response in OVCA ascites. Discussion: Our findings identified a CDCP1+ EVs subcluster in the ascites of OVCA patients as a possible biomarker for EOC prevention.

Metastatic prostate cancer-derived extracellular vesicles facilitate osteoclastogenesis by transferring the CDCP1 protein.

Bone metastases are still incurable and result in the development of clinical complications and decreased survival for prostate cancer patients. Recently, a number of studies have shown that extracellular vesicles (EVs) play important roles in tumour progression. Here, we show that EVs from metastatic prostate cancer cells promote osteoclast formation in the presence of receptor activator of NF-κB ligand (RANKL). EV characterization followed by functional siRNA screening identified CUB-domain containing protein 1 (CDCP1), a transmembrane protein, as an inducer of osteoclastogenesis. Additionally, CDCP1 expression on plasma-derived EVs was upregulated in bone metastatic prostate cancer patients. Our findings elucidate the effect of EVs from metastatic prostate cancer cells on osteoclast formation, which is promoted by CDCP1 located on EVs. Furthermore, our data suggested that CDCP1 expression on EVs might be useful to detect bone metastasis of prostate cancer.

CUB Domain-Containing Protein 1 (CDCP1) is a rational target for the development of imaging tracers and antibody-drug conjugates for cancer detection and therapy.

Rationale: An antibody-drug conjugate (ADC) is a targeted therapy consisting of a cytotoxic payload that is linked to an antibody which targets a protein enriched on malignant cells. Multiple ADCs are currently used clinically as anti-cancer agents significantly improving patient survival. Herein, we evaluated the rationale of targeting the cell surface oncoreceptor CUB domain-containing protein 1 (CDCP1) using ADCs and assessed the efficacy of CDCP1-directed ADCs against a range of malignant tumors. Methods: CDCP1 mRNA expression was evaluated using large transcriptomic datasets of normal/tumor samples for 23 types of cancer and 15 other normal organs, and CDCP1 protein expression was examined in 34 normal tissues, >300 samples from six types of cancer, and in 49 cancer cell lines. A recombinant human/mouse chimeric anti-CDCP1 antibody (ch10D7) was labelled with 89Zirconium or monomethyl auristatin E (MMAE) and tested in multiple pre-clinical cancer models including 36 cancer cell lines and three mouse xenograft models. Results: Analysis of CDCP1 expression indicates elevated CDCP1 expression in the majority of the cancers and restricted expression in normal human tissues. Antibody ch10D7 demonstrates a high affinity and specificity for CDCP1 inducing cell signalling via Src accompanied by rapid internalization of ch10D7/CDCP1 complexes in cancer cells. 89Zirconium-labelled ch10D7 accumulates in CDCP1 expressing cells enabling detection of pancreatic cancer xenografts in mice by PET imaging. Cytotoxicity of MMAE-labelled ch10D7 against kidney, colorectal, lung, ovarian, pancreatic and prostate cancer cells in vitro, correlates with the level of CDCP1 on the plasma membrane. ch10D7-MMAE displays robust anti-tumor effects against mouse xenograft models of pancreatic, colorectal and ovarian cancer. Conclusion: CDCP1 directed imaging agents will be useful for selecting cancer patients for personalized treatment with cytotoxin-loaded CDCP1 targeting agents including antibody-drug conjugates.

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.