Unraveling the Role of PCDH9 in Breast Cancer and Identifying Therapeutic Strategies for PCDH9-Deficient Tumors.

Introduction: Protocadherin 9 (PCDH9), a member of the cadherin superfamily of transmembrane proteins, plays a role in cell adhesion and neural development. Recent studies suggest that PCDH9 may function as a tumor suppressor in certain cancers, though its specific role in breast cancer remains unclear. Methods: UALCAN database to retrieve information on PCDH9 expression in breast cancer tissues compared with that in normal tissues. The biological effects of PCDH9 in breast cancer cells were analyzed using the DepMap database. Stable knockdown or overexpression of PCDH9 in breast cancer cell lines and subsequently assessed tumor cell proliferation and migration. Synthetic lethal screening was conducted for breast cancer cells with low PCDH9 expression or deficiency. Results: In this study, we observed significant downregulation of PCDH9 in breast cancer tissues, with its expression negatively correlated with progression-free survival. Further investigations revealed that decreased PCDH9 expression promotes breast cancer cell proliferation and migration, while overexpression of PCDH9 has the opposite effect. Subsequently, we identified the TAS-102, an approved drug for metastatic colorectal cancer, exhibited selective cytotoxicity against breast cancer cells with low PCDH9 expression. Conclusion and discussion: In summary, our study identified PCDH9 as a tumor suppressor in breast cancer and highlighted TAS-102 as a potential therapeutic option for tumors with low PCDH9 expression or deficiency. The specific interaction between TAS-102 and PCDH9 warrants further exploration, providing deeper insights into its mode of action in treating PCDH9-deficient breast cancer.

Expression of Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) Candidate Genes EDA2R, PCDH9, and TRAF7 in Normal Human Kidney Development and CAKUT.

Approximately half of the cases of chronic kidney disease (CKD) in childhood are caused by congenital anomalies of the kidney and urinary tract (CAKUT). Specific genes were identified as having significant importance in regard to the underlying genetic factors responsible for the CAKUT phenotype, and in our research, we focused on analyzing and comparing the expression levels of ectodysplasin A2 receptor (EDA2R), protocadherin9 (PCDH9), and TNF receptor-associated factor 7 (TRAF7) proteins in the cortex and medulla of healthy control kidneys during developmental phases 2, 3, and 4. We also performed an analysis of the area percentages of the mentioned proteins in the cortical and medullary sections of healthy embryonic and fetal kidneys compared to those affected by CAKUT, including duplex kidneys (DK), horseshoe kidneys (HK), hypoplastic kidneys (HYP), and dysplastic kidneys (DYS). We found that the CAKUT candidate gene proteins EDA2R, PCDH9, and TRAF7 are all expressed during normal human kidney development stages. In DYS, the expression of EDA2R was higher than in normal kidneys, likely due to EDA2R's role in apoptosis, which was upregulated in specific cases and could possibly contribute to the formation of DYS. The expression of PCDH9 was lower in HK, which can be attributed to the possible role of PCDH9 in cell migration suppression. Decreased PCDH9 expression is linked to increased cell migration, potentially contributing to the development of HK. The level of TRAF7 expression was reduced in all examined kidney disorders compared to normal kidneys, suggesting that this reduction might be attributed to the crucial role of TRAF7 in the formation of endothelium and ciliogenesis, both of which are essential for normal kidney development. Further research is required to ascertain the function of these proteins in both the typical development of the kidney and in CAKUT.

The expression of PCDH9 was absent in prostate cancer tissues in the high-score group and was associated with the expressions of p53, Rb and STAT3 / 现代泌尿外科杂志

【Objective】 To explore the expression of PCDH9 loss in regulating cell cycle and promoting tumor progression. 【Methods】 The clinical records of 127 cases of prostate cancer treated during 2018 and 2023 were collected, including 87 paraffin tissue samples from the G4-5 group and 40 from the G1-3 group. The expressions of PCDH9, p53, Rb and STAT3 were detected with immunohistochemical staining, and the relationship between their expressions and clinicopathological characteristics was analyzed. 【Results】 The expression deletion rate of PCDH9 in prostate cancer tissues in G4-5 group (44.8% vs.7.5%) was significantly higher than that in G1-3 group (P<0.001). The positive expression rates of p53 and STAT3 were 34.5% and 89.7%, respectively, and the expression loss rate of Rb was 27.6% in G4-5 group. The expression loss rates of PCDH9 and Rb were associated with neuroendocrine-like histological morphology, nerve invasion and vascular invasion (P<0.05). In G4-5 group of prostate cancer, PCDH9 expression was positively correlated with the expressions of p53 (r=0.345, P<0.05), Rb (r=0.503, P<0.05) and STAT3 (r=0.224, P<0.05). 【Conclusion】 PCDH9 is prone to loss of expression in high-group prostate cancer tissues, especially in cases with neuroendocrine-like histological morphology, which may regulate the cell cycle through the STAT3 signaling pathway, thereby promoting tumor progression.

PCDH9 suppresses melanoma proliferation and cell migration.

Background: Melanoma has dramatically increased during last 30 years with low 5-year survival and prognosis rate. Methods: Melanoma cells (A375 and G361) were chosen as the in vitro model. The immunohistochemical (IHC) analysis and bioinformatics mining exhibited the suppression of PCDH9 on melanoma. The interference and overexpression of PCDH9 were infected by lentivirus. The effects of PCDH9 on melanoma cells were assessed in terms of alteration of PCDH9 such as cell viability, apoptosis, cell cycle, and wound-healing assay. Moreover, expressions of PCDH9 with other genes (MMP2, MMP9, CCND1, and RAC1) were also assessed by PCR. Results: The alteration of PCDH9 has a negative correlation with MMP2, MMP9, and RAC1 but had a positive correlation with CCND1 (Cyclin D1) and apoptosis. Increase of PCDH9 could suppress melanoma cells and inhibit migration but not exert significant effects on cell cycle. IHC showed lower PCDH9 expression in melanoma tissue with main expression in cytoplasm. Conclusion: Overexpressed PCDH9 suppressed melanoma cells, and PCDH9 can be considered as an independent prognostic factor for melanoma; even re-expression of PCDH9 can serve as a potential therapeutic strategy for melanoma treatment.

Circ_0084043-miR-134-5p axis regulates PCDH9 to suppress melanoma.

The low survival rates, poor responses, and drug resistance of patients with melanoma make it urgent to find new therapeutic targets. This study investigated whether the circ_0084043-miR-134-5p axis regulates the antitumor effect of protocadherin 9 (PCDH9) in melanoma. Ectopic expression or knock down (KD) of PCDH9 with a lentivirus vector, we explored its effects on the proliferation, invasion, and apoptosis of melanoma and verified its regulatory effect on ras-related C3 botulinum toxin substrate 1 (RAC1), proline-rich tyrosine kinase 2 (Pyk2), Cyclin D1, matrix metalloproteinase 2 (MMP2), and MMP9. We further observed the effect of KD circ_0084043 on the malignant behavior of melanoma and studied whether circ_0084043 sponged miR-134-5p and regulated PCDH9. We found that circ_0084043 was overexpressed in melanoma and associated with the malignant phenotype. PCDH9 was poorly expressed in human melanoma tissues, and overexpression of PCDH9 inhibited melanoma progression. Quantitative real-time PCR and Western blotting results showed that overexpression of PCDH9 could downregulate RAC1, MMP2, and MMP9 and upregulate Pyk2 and Cyclin D1. Circ_0084043 KD inhibited invasion and promoted apoptosis in melanoma cells. Circ_0084043 could sponge miR-134-5p and thus indirectly regulate PCDH9. Furthermore, we discovered that inhibiting circ_0084043 had an anti-PD-Ll effect. In vivo, PCDH9 overexpression inhibited melanoma tumor growth, but PCDH9 KD promoted it. In conclusion, PCDH9, which is regulated by the circ 0084043-miR-134-5p axis, can suppress malignant biological behavior in melanoma and influence the expression levels of Pyk2, RAC1, Cyclin D1, MMP2, and MMP9.

Genome-wide association study in patients with posterior urethral valves.

Congenital lower urinary tract obstructions (LUTO) are most often caused by posterior urethral valves (PUV), a male limited anatomical obstruction of the urethra affecting 1 in 4,000 male live births. Little is known about the genetic background of PUV. Here, we report the largest genome-wide association study (GWAS) for PUV in 4 cohorts of patients and controls. The final meta-analysis included 756 patients and 4,823 ethnicity matched controls and comprised 5,754,208 variants that were genotyped or imputed and passed quality control in all 4 cohorts. No genome-wide significant locus was identified, but 33 variants showed suggestive significance (P < 1 × 10-5). When considering only loci with multiple variants residing within < 10 kB of each other showing suggestive significance and with the same effect direction in all 4 cohorts, 3 loci comprising a total of 9 variants remained. These loci resided on chromosomes 13, 16, and 20. The present GWAS and meta-analysis is the largest genetic study on PUV performed to date. The fact that no genome-wide significant locus was identified, can be explained by lack of power or may indicate that common variants do not play a major role in the etiology of PUV. Nevertheless, future studies are warranted to replicate and validate the 3 loci that yielded suggestive associations.

The Chemopreventive Role of ß-Elemene in Cholangiocarcinoma by Restoring PCDH9 Expression.

Background: ß-Elemene, an effective anticancer component isolated from the Chinese herbal medicine Rhizoma Zedoariae, has been proved to have therapeutic potential against multiple cancers by extensive clinical trials and experimental research. However, its preventive role in cholangiocarcinoma (CCA) and the mechanisms of action of ß-elemene on CCA need to be further investigated. Methods: A thioacetamide (TAA)-induced pre-CCA animal model was well-established, and a low dosage of ß-elemene was intragastrically (i.g.) administered for 6 months. Livers were harvested and examined histologically by a deep-learning convolutional neural network (CNN). cDNA array was used to analyze the genetic changes of CCA cells following ß-elemene treatment. Immunohistochemical methods were applied to detect ß-elemene-targeted protein PCDH9 in CCA specimens, and its predictive role was analyzed. ß-Elemene treatment at the cellular or animal level was performed to test the effect of this traditional Chinese medicine on CCA cells. Results: In the rat model of pre-CCA, the ratio of cholangiolar proliferation lesions was 0.98% ± 0.72% in the control group, significantly higher than that of the ß-elemene (0. 47% ± 0.30%) groups (p = 0.0471). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the top 10 pathways affected by ß-elemene treatment were associated with energy metabolism, and one was associated with the cell cycle. ß-Elemene inactivated a number of oncogenes and restored the expression of multiple tumor suppressors. PCDH9 is a target of ß-elemene and displays an important role in predicting tumor recurrence in CCA patients. Conclusions: These findings proved that long-term use of ß-elemene has the potential to interrupt the progression of CCA and improve the life quality of rats. Moreover, ß-elemene exerted its anticancer potential partially by restoring the expression of PCDH9.

COP1 Acts as a Ubiquitin Ligase for PCDH9 Ubiquitination and Degradation in Human Glioma.

Constitutive photomorphogenic 1 (COP1, also known as RFWD2), a ring-finger-type E3 ubiquitin ligase, has been reported to play a pivotal role in the regulation of cell growth, apoptosis, and DNA repair. Accumulating evidence has suggested that COP1 plays a role in tumorigenesis by triggering the ubiquitination and degradation of its substrates, but the potential mechanism remains unclear. In this study, COP1 was used as a bait in a yeast two-hybrid experiment to screen COP1-interacting proteins in a human brain cDNA library, and the results indicated that protocadherin 9 (PCDH9) was a potential binding protein of COP1. The interaction between and colocalization of COP1 and PCDH9 was further confirmed by coimmunoprecipitation (co-IP) assay and immunofluorescent staining. Subsequently, we demonstrated that COP1 acted as an E3 ligase to promote the ubiquitination and degradation of PCDH9 through the proteasome pathway in glioma cells. Furthermore, we identified that the type of COP1 mediated PCDH9 ubiquitination was Lys48-linked polyubiquitination. Finally, we found that the COP1 protein level was inversely correlated with the PCDH9 protein level in human glioma tissues. Taken together, our results suggest that COP1 is an E3 ubiquitin ligase for PCDH9 and reveal an important mechanism for PCDH9 regulation in human glioma.

piR-001773 and piR-017184 promote prostate cancer progression by interacting with PCDH9.

Prostate cancer is one of the most common malignancies and the major cause of cancer-related death in men. Increasing evidence has revealed that P-element-induced wimpy (piwi)-interacting RNAs (piRNAs) play an important role in tumor progression. Few studies have been explored the functional mechanism of piRNAs in prostate cancer progression. In the present study, we demonstrated that piR-001773 and piR-017184 were increased in prostate cancer tissues. Protocadherin 9 (PCDH9) was downregulated and acted as a tumor suppressor in prostate cancer cells. PCDH9 could bind to p85α, the regulatory subunit of PI3K. The downregulation of PCDH9 in PCa cells resulted in an increase in AKT phosphorylation and activity. PCDH9 was posttranscriptionally regulated by piR-001773 and piR-017184. The upregulation of piR-001773 and piR-017184 promoted tumor growth both in vitro and in vivo. In addition, the downregulation of piR-001773 and piR-017184 markedly inhibited tumor growth. In conclusion, these results indicated that piR-001773 and piR-017184 are oncogenic RNAs and thus might be therapeutic targets in prostate cancer.

MiR-200a-3p promoted the malignant behaviors of ovarian cancer cells through regulating PCDH9.

BACKGROUND: Increasing evidence has revealed that the aberrant expression of microRNAs (miRNAs) plays vital roles in the development and progression of ovarian cancer. MiR-200a-3p was found to act as an oncogene in a variety of cancers, however, the expression and function of miR-200a-3p in ovarian cancer has not been characterized. MATERIALS AND METHODS: The expression of miR-200a-3p in ovarian cancer tissues and cell lines was detected by the RT-qPCR. The influence of miR-200a-3p on the growth of ovarian cancer cells was determined with the Cell Counting Kit-8 assay, colony formation and cell invasion assay. The binding of miR-200a-3p with the 3'-untranslated region (UTR) of PDCH9 was detected by luciferase reporter assay. The expression of PCDH9 was investigated by RT-qPCR and Western blot analysis. RESULTS: miR-200a-3p was up-regulated in ovarian cancer tissues and cell lines. Highly expressed miR-200a-3p was significantly associated with the tumor size, tumor metastasis and TNM stage. Overexpression of miR-200a-3p markedly promoted the proliferation, colony formation and invasion of ovarian cancer cells. Functional study uncovered that miR-200a-3p bound the 3'-untranslated region (UTR) of PCDH9 and decreased the expression of PCDH9 in ovarian cancer cells. The expression of miR-200a-3p in ovarian cancer tissues was significantly negatively correlated with that of PCDH9. Restored PCDH9 inhibited the promoting effect of miR-200a-3p on the proliferation of ovarian cancer cells. CONCLUSION: Our results suggested the potential oncogenic function of miR-200a-3p via modulating PCDH9 in ovarian cancer.

Semaphorin 3A (SEMA3A), protocadherin 9 (PCdh9), and S100 calcium binding protein A3 (S100A3) as potential biomarkers of carcinogenesis and chemoresistance of different neoplasms, including ovarian cancer - review of literature.

Ovarian cancer is the fifth leading cause of cancer-related deaths in women. Its high mortality rate results from lack of adequate and sensitive methods allowing for the detection of the early stages of the disease, as well as low efficiency of the treatment, caused by the cytotoxic drug resistance of cancer cells. Unfortunately, tumours are able to develop new pathways and protective mechanisms that allow them to survive toxic conditions of chemotherapy. Therefore, intensive search for new genes and proteins involved in resistance to cytotoxic drugs is still needed, especially from a clinical point of view. The article presents an overview of the available literature on the role of semaphorin 3A (SEMA3A), protocadherin 9 (PCDH9), and S100 calcium binding protein A3 (S100A3) in carcinogenesis and chemoresistance of various tumors including ovarian cancer. As it turns out, the role of described genes/proteins is not limited only to their native biological activity but they function also as an oncogenic or suppressor factors in the tumor development. Moreover, they can also play an important role in development of drug resistance, as it was shown in ovarian cancer cell lines.

Dual inhibition of PCDH9 expression by miR-215-5p up-regulation in gliomas.

The clinical prognosis of malignant gliomas is poor and PCDH9 down-regulation is strongly associated with its poor prognosis. But the mechanism of PCDH9 down-regulation is unknown. Abnormal miRNAs profiles regulate tumor phenotypes through inhibiting their target genes and miRNAs could inhibit target genes more efficiently by binding to both the promoter and 3'UTR of target genes. In this study, to search the dual inhibitory miRNAs which suppress PCDH9 expression in gliomas, we performed an integrative analysis of databases including miRDB, TargetScan, microPIR and miRCancer. We identified three candidate miRNAs which were predicted to bind both the promoter and 3'UTR of PCDH9 and up-regulated in gliomas. Then, we validated miR-215-5p up-regulation and PCDH9 down-regulation in glioma samples and demonstrated that miR-215-5p could inhibit the mRNA and protein levels of PCDH9 in glioma cell lines by targeting its promoter and 3' UTR at the same time. Moreover, miR-215-5p could increase glioma cell proliferation, clone formation, in-vitro migration and reduce apoptosis via inhibiting PCDH9 expression. Our study provides evidence for a novel dual inhibition of PCDH9 by miR-215-5p in gliomas and suggests that miR-215-5p might be a therapeutic target for the treatment of gliomas.

Genetic Mapping in Mice Reveals the Involvement of Pcdh9 in Long-Term Social and Object Recognition and Sensorimotor Development.

BACKGROUND: Quantitative genetic analysis of basic mouse behaviors is a powerful tool to identify novel genetic phenotypes contributing to neurobehavioral disorders. Here, we analyzed genetic contributions to single-trial, long-term social and nonsocial recognition and subsequently studied the functional impact of an identified candidate gene on behavioral development. METHODS: Genetic mapping of single-trial social recognition was performed in chromosome substitution strains, a sophisticated tool for detecting quantitative trait loci (QTL) of complex traits. Follow-up occurred by generating and testing knockout (KO) mice of a selected QTL candidate gene. Functional characterization of these mice was performed through behavioral and neurological assessments across developmental stages and analyses of gene expression and brain morphology. RESULTS: Chromosome substitution strain 14 mapping studies revealed an overlapping QTL related to long-term social and object recognition harboring Pcdh9, a cell-adhesion gene previously associated with autism spectrum disorder. Specific long-term social and object recognition deficits were confirmed in homozygous (KO) Pcdh9-deficient mice, while heterozygous mice only showed long-term social recognition impairment. The recognition deficits in KO mice were not associated with alterations in perception, multi-trial discrimination learning, sociability, behavioral flexibility, or fear memory. Rather, KO mice showed additional impairments in sensorimotor development reflected by early touch-evoked biting, rotarod performance, and sensory gating deficits. This profile emerged with structural changes in deep layers of sensory cortices, where Pcdh9 is selectively expressed. CONCLUSIONS: This behavior-to-gene study implicates Pcdh9 in cognitive functions required for long-term social and nonsocial recognition. This role is supported by the involvement of Pcdh9 in sensory cortex development and sensorimotor phenotypes.

Analysis of changes in transcription start site distribution by a classification approach.

Change in transcription start site (TSS) usage is an important mechanism for the control of transcription process, and has a significant effect on the isoforms being transcribed. One of the goals in the study of TSS is the understanding of how and why their usage differs in different tissues or under different conditions. In light of recent efforts in the mapping of transcription start site landscape using high-throughput sequencing approaches, a quantitative and automated method is needed to process all the data that are being produced. In this work we propose a statistical approach that will classify changes in TSS distribution between different samples into several categories of changes that may have biological significance. Genes selected by the classifiers can then be analyzed together with additional supporting data to determine their biological significance. We use a set of time-course TSS data from mouse dendritic cells stimulated with lipopolysaccharide (LPS) to demonstrate the usefulness of our method.