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Cytoskeleton‐associated protein 4 (CKAP4) is a cell surface receptor for Dickkopf 1 (DKK1), a secreted protein. The DKK1–CKAP4 pathway is activated in various malignant tumors, including pancreatic, lung, esophageal, and liver cancers, to promote tumor growth. Thus, CKAP4 has been expected to represent a novel molecular target of cancer therapy. Recombinant mouse anti‐CKAP4 antibodies were generated based on an original mouse antibody (3F11‐2B10) and inhibited DKK1–CKAP4 signaling and xenograft tumor formation induced by pancreatic cancer cells, which was comparable with 3F11‐2B10. From the 3F11‐2B10 nucleotide sequence, humanized anti‐CKAP4 antibody (Hv1Lt1) was subsequently developed. The binding affinity of Hv1Lt1 for CKAP4 was superior to that of 3F11‐2B10. Hv1Lt1 inhibited DKK1 binding to CKAP4, AKT activity, and sphere formation of pancreatic cancer cells, which was comparable with 3F11‐2B10. Hv1Lt1 also suppressed xenograft tumor formation induced by human pancreatic cancer cells and tumor growth in murine cancer models, in which murine pancreatic cancer organoids were orthotopically transplanted into the pancreas. In resected tumor samples from mice treated with Hv1Lt1, anti‐tumor immune reactions were modulated and cytotoxic T cells were highly infiltrated in the tumor microenvironment. Additionally, combination of Hv1Lt1 and other chemotherapy drugs exhibited stronger effects compared with monotherapy. These results suggest that Hv1Lt1 represents a promising anti‐cancer therapy. [ABSTRACT FROM AUTHOR]

Dickkopf1 (DKK1) is a secretory protein that antagonizes oncogenic Wnt signaling by binding to the Wnt coreceptor lowdensity lipoprotein receptor-related protein 6 (LRP6). DKK1 may also regulate its own signaling to promote cancer cell proliferation, but the mechanism is not understood. Here, we identified cytoskeleton-associated protein 4 (CKAP4) as a DKK1 receptor and evaluated CKAP4-mediated DKK1 signaling in cancer cell proliferation. We determined that DKK1 binds CKAP4 and LRP6 with similar affinity but interacts with these 2 receptors with different cysteine-rich domains. DKK1 induced internalization of CKAP4 in a clathrin-dependent manner, further supporting CKAP4 as a receptor for DKK1. DKK1/CKAP4 signaling activated AKT by forming a complex between the proline-rich domain of CKAP4 and the Src homology 3 domain of PI3K, resulting in proliferation of normal cells and cancer cells. Expression of DKK1 and CKAP4 was frequent in tumor lesions of human pancreatic and lung cancers, and simultaneous expression of both proteins in patient tumors was negatively correlated with prognosis and relapse-free survival. An anti-CKAP4 antibody blocked the binding of DKK1 to CKAP4, suppressed AKT activity in a human cancer cell line, and attenuated xenograft tumor formation in immunodeficient mice. Together, our results suggest that CKAP4 is a potential therapeutic target for cancers that express both DKK1 and CKAP4., Introduction Dickkopf1 (DKK1) was originally identified as an embryonic head inducer in Xenopus embryos and shown to be a secreted protein that antagonizes Wnt signaling (1, 2). Of the multiple [...]

Although the Pipelle endometrial biopsy is widely performed as a practical and minimally invasive test for endometrial disease(s), its effectiveness in ovarian cancer has not been explored. The aim of the present study was to evaluate the results of Pipelle endometrial biopsy for ovarian, fallopian tube, and peritoneal cancers. A pre-treatment Pipelle-endometrial biopsy was performed in 90 patients with ovarian, fallopian tube, or peritoneal cancers between January 2014 and November 2021. We retrospectively analysed the association between the results of Pipelle endometrial biopsy and clinicopathological data. Moreover, we evaluated their impact on the following treatment in advanced cases initially treated with chemotherapy. The sensitivity and false-negative rates for Pipelle endometrial biopsy were 25/90 (27.8%) and 65/90 (72.2%) in all patients, respectively, and 23/56 (41.0%) and 33/56 (58.9%) in cases with advanced disease (stages III and IV), respectively. Pipelle-positive endometrial biopsy-positive (Pipelle-positive) was not observed in 29 patients with clinical stage I disease, and Pipelle-positive patients exhibited significantly more high-grade serous carcinomas, and positive peritoneal, endometrial, and cervical cytologies than Pipelle-endometrial biopsy-negative cases. Surgical pathology was confirmed in 23 Pipelle-positive patients, and 17/23 (74.0%) had the same diagnosis as that for Pipelle endometrial biopsy. Conversely, 6/23 (26.0%) patients exhibited a minor diagnostic discrepancy between Pipelle endometrial biopsy and surgical pathology. Nineteen of the 38 (50.0%) patients initially treated with chemotherapy were identified as Pipelle-positive, contributing to a prompt histological diagnosis and pre-treatment tumour sampling. Companion diagnostic tests were performed using Pipelle endometrial biopsy samples from 4 inoperable patients. Although the positive rate of Pipelle endometrial biopsy in ovarian, fallopian tube, and peritoneal cancers is low, Pipelle endometrial biopsy may enable prompt histological diagnosis and initiation of chemotherapy while collecting tumour tissue for genetic testing in some cases with advanced disease. The effectiveness of pre-treatment Pipelle endometrial biopsy for ovarian, fallopian tube, and peritoneal cancers remains unclear. This study demonstrated that Pipelle endometrial biopsy may enable prompt histological diagnosis and initiation of chemotherapy while collecting tumour tissue for genetic testing in some cases with advanced disease. This was a single-centre, retrospective study; as such, the effectiveness of Pipelle endometrial biopsy should be evaluated in larger prospective studies, including comparisons with other tumour sampling methods. [ABSTRACT FROM AUTHOR]

Simple Summary: Conotoxins are small, structured components found in the venom of predatory cone snails. They were proven to be valuable probes and models for drug discovery and protein evolution studies. Conotoxins present an opportunity to study protein divergence and discover potential human therapeutic landscapes. Although there is considerable literature on conotoxin evolution and activity, what pushed conotoxin divergence remains unclear. Hence, in this paper, we conducted a two-phase study that investigated conotoxin evolution in terms of divergence, followed by structural analysis to determine the relevant structural elements. By understanding the evolution of conotoxins, we identified patterns that account for their superior specificity. The results revealed similarities based on the cone snail's diet preference. The structural elements are in synch with their target prey preference as if cone snails evolved to fine-tune their conopeptide armory to respond to evolutionary pressures by producing conotoxins selective for their prey of choice. We identified several structural elements that account for this specificity. Conservation patterns are observed within diet subgroups but are divergent from other groups. Predatory cone snails (Conus) developed a sophisticated neuropharmacological mechanism to capture prey, escape against other predators, and deter competitors. Their venom's remarkable specificity for various ion channels and receptors is an evolutionary feat attributable to the venom's variety of peptide components (conotoxins). However, what caused conotoxin divergence remains unclear and may be related to the role of prey shift. Principal component analysis revealed clustering events within diet subgroups indicating peptide sequence similarity patterns based on the prey they subdue. Molecular analyses using multiple sequence alignment and structural element analysis were conducted to observe the events at the molecular level that caused the subgrouping. Three distinct subgroups were identified. Results showed homologous regions and conserved residues within diet subgroups but divergent between other groups. We specified that these structural elements caused subgrouping in alpha conotoxins that may play a role in function specificity. In each diet subgroup, amino acid character, length of intervening amino acids between cysteine residues, and polypeptide length influenced subgrouping. This study provides molecular insights into the role of prey shift, specifically diet preference, in conotoxin divergence. [ABSTRACT FROM AUTHOR]