LncRNA FAM83H-AS1 inhibits ferroptosis of endometrial cancer by promoting DNMT1-mediated CDO1 promoter hypermethylation.

Endometrial cancer (EC) is the most prevalent gynecological epithelial malignancy. DNA methylation is a promising cancer biomarker, but limited use for detecting EC. We previously found that the level of cysteine dioxygenase 1 (CDO1) promoter methylation was elevated in EC patients through methylomics, but the role and mechanism of CDO1 in EC remained unclear. Here, the methylation level of CDO1 promoter was detected by Bisulfite-sequencing PCR (BSP) and methylation-specific PCR (MSP) (bisulfite-conversion-based PCR methods, which remain the most commonly used techniques for methylation detection). Cells were incubated with erastin (the ferroptosis activator). Cell vitality was measured using the cell counting kit-8 (CCK-8) assay. FAM83H-AS1 cellular distribution was analyzed by the fluorescence in situ hybridization (FISH) assay. Lipid ROS level was examined by BODIPY-C11 staining. The interactions between FAM83H-AS1, CDO1, and DNA methyltransferase1 (DNMT1) were analyzed by RNA binding protein immunoprecipitation (RIP) or chromatin immunoprecipitation (ChIP) assay. The xenograft mouse model was utilized to test CDO1 and FAM83H-AS1's influence on tumor development in vivo. Results showed that CDO1 was hypermethylated and downregulated in EC. CDO1 knockdown reduced erastin-induced ferroptosis in EC cells. Mechanistically, DNMT1 is a DNA methyltransferase, which can transfer methyl groups to cytosine nucleotides in genomic DNA. Long non-coding RNA (lncRNA) FAM83H-AS1 increased CDO1 promoter methylation level and inhibited its expression in EC cells by recruiting DNMT1. CDO1 knockdown or FAM83H-AS1 overexpression promoted EC tumor growth in vivo. LncRNA FAM83H-AS1 inhibited ferroptosis in EC by recruiting DNMT1 to increase CDO1 promoter methylation level and inhibit its expression.

Amelogenesis imperfecta in a Chinese family resulting from a FAM83H variation and the effect of FAM83H on the secretion of enamel matrix proteins.

OBJECTIVES: To investigate the variant of an amelogenesis imperfecta (AI) family and to explore the function of the FAM83H (family with sequence similarity 83 member H) in the enamel formation. MATERIALS AND METHODS: We investigated a five-generation Chinese family diagnosed with AI; clinical data was collected, whole-exome sequencing (WES) was conducted to explore the pathogenic gene and variants and Sanger sequencing was used to verify the variants. The three-dimensional protein structures of wild-type and mutant FAM83H were predicted using alpha fold 2. To study the possible regulatory function of Fam83h on amelogenesis, immunolocalization was performed to observe the expression of Fam83h protein in Sprague-Dawley rat postnatal incisors. The mRNA and protein level of amelogenin, enamelin, kallikrein-related peptidase-4 and ameloblastin were also detected after the Fam83h was knocked down by small interfering RNA (siRNA) in HAT-7 cells. RESULTS: A known nonsense variant (c.973 C > T) in exon 5 of FAM83H gene was found in this family, causing a truncated protein (p.R325X). Immunolocalization of Fam83h in Sprague-Dawley rat postnatal incisors showed that Fam83h protein expression was detected in presecretory and secretory stages. When Fam83h expression was reduced by siRNA, the expression of amelogenin, enamelin, kallikrein-related peptidase-4 decreased. However, the expression of ameloblastin increased. CONCLUSIONS: FAM83H gene variant (c.973 C > T) causes AI. FAM83H regulates the secretion of enamel matrix proteins and affects ameloblast differentiation. CLINICAL RELEVANCE: This study provided that FAM83H variants could influence enamel formation and provided new insights into the pathogenesis of AI.

Tooth ultrastructure changes induced by a nonsense mutation in the FAM83H gene: insights into the diversity of amelogenesis imperfecta.

OBJECTIVES: The current research on single-nucleotide polymorphism (SNP) mutation sites at different positions of the FAM83H gene and their phenotypic changes leading to amelogenesis imperfecta (AI) is inconsistent. We identified a previously reported heterozygous nonsense mutation c.1192C>T (p.Q398*) in the FAM83H gene and conducted a comprehensive analysis of the dental ultrastructure and chemical composition changes induced by this mutation. Additionally, we predicted the protein feature affected by this mutation site. The aim was to further deepen our understanding of the diversity of AI caused by different mutation sites in the FAM83H gene. METHODS: Whole-exome sequencing (WES) and Sanger sequencing were used to confirm the mutation sites. Physical features of the patient's teeth were investigated using various methods including cone beam computer tomography (CBCT), scanning electron microscopy (SEM), contact profilometry (roughness measurement), and a nanomechanical tester (nanoindentation measurement). The protein features of wild-type and mutant FAM83H were predicted using bioinformatics methods. RESULTS: One previously discovered FAM83H heterozygous nonsense mutation c.1192C>T (p.Q398*) was detected in the patient. SEM revealed inconsistent dentinal tubules, and EDS showed that calcium and phosphorus were lower in the patient's dentin but higher in the enamel compared to the control tooth. Roughness measurements showed that AI patients' teeth had rougher occlusal surfaces than those of the control tooth. Nanoindentation measurements showed that the enamel and dentin hardness values of the AI patients' teeth were both significantly reduced compared to those of the control tooth. Compared to the wild-type FAM83H protein, the mutant FAM83H protein shows alterations in stability, hydrophobicity, secondary structure, and tertiary structure. These changes could underlie functional differences and AI phenotype variations caused by this mutation site. CONCLUSIONS: This study expands the understanding of the effects of FAM83H mutations on tooth structure. CLINICAL RELEVANCE: Our study enhances our understanding of the genetic basis of AI and may contribute to improved diagnostics and personalized treatment strategies for patients with FAM83H-related AI.

FAM83H-AS1/miR-485-5p/MEF2D axis facilitates proliferation, migration and invasion of hepatocellular carcinoma cells.

BACKGROUND: Abundant evidence has manifested that long noncoding RNAs (lncRNAs) are closely implicated in human cancers, including hepatocellular carcinoma (HCC). Remarkably, lncRNA FAM83H antisense RNA 1 (FAM83H-AS1) has been reported to be a tumor-propeller in multiple cancers. However, its effect on HCC progression remains unknown. METHODS: FAM83H-AS1 expression was analyzed by RT-qPCR. Colony formation, EdU, and flow cytometry as well as transwell assays were implemented to analyze the biological functions of FAM83H-AS1 on HCC progression. Luciferase reporter, RIP and RNA pull-down assays were implemented to detect the interaction among FAM83H-AS1, microRNA-485-5p (miR-485-5p), and myocyte enhancer factor 2D (MEF2D) in HCC cells. RESULTS: FAM83H-AS1 expression in HCC cells was markedly elevated. FAM83H-AS1 accelerated cell proliferation, migration and invasion whereas inhibiting cell apoptosis in HCC. Besides, we confirmed that FAM83H-AS1 acts as a miR-485-5p sponge in HCC cells. Additionally, MEF2D was verified to be a direct target of miR-485-5p. FAM83H-AS1 could upregulate MEF2D expression via sponging miR-485-5p. Further, rescue experiments testified that MEF2D upregulation or miR-485-5p downregulation offset the repressive effect of FAM83H-AS1 depletion on HCC cell progression. CONCLUSIONS: FAM83H-AS1 facilitates HCC malignant progression via targeting miR-485-5p/MEF2D axis, suggesting that FAM83H-AS1 may be a promising biomarker for HCC treatment in the future.

Long non-coding RNA FAM83H-AS1 as an emerging marker for diagnosis, prognosis and therapeutic targeting of cancer.

Incidence and mortality rates of cancer continue to increase greatly despite the improved diagnostic and therapeutic methods. Based on GLOBOCAN estimates, the numbers of new cancer cases reported in 2018 were ~18.1 million, while the numbers of cancer mortalities were ~9.6 million. It remains difficult to diagnose most cancer patients at early stages. Although cancer therapy market is rapidly evolving, the effectiveness of therapy is still inadequate. Therefore, exploring new biomarkers for diagnosis, prognosis and treatment is essential for cancer management. Long non-coding RNAs (lncRNAs) are unique regulatory molecules that control several cellular processes and are implicated in diverse human diseases including cancer. LncRNAs could serve as potential biomarkers for cancer patients to aid diagnosis and determine prognosis. In addition, numerous lncRNAs have proved their ability to predict response to cancer treatment. FAM83H antisense RNA 1 (FAM83H-AS1) is among those highly dysregulated lncRNAs in cancer. FAM83H-AS1 was demonstrated to participate in the progression of different malignancies and also shown to play a vital role in diagnosis, prognosis and treatment. Here, we analyse recent studies concerning the oncogenic role and molecular mechanisms of lncRNA FAM83H-AS1 in the following cancer types: bladder, breast, lung, hepatocellular, colorectal, gastric, pancreatic, ovarian, cervical cancer as well as glioma.

The gain-of-function FAM83H mutation caused hypocalcification amelogenesis imperfecta in a Chinese family.

OBJECTIVES: Autosomal-dominant hypocalcification amelogenesis imperfecta (ADHCAI) is a hereditary disease characterized by enamel defects. ADHCAI is mainly caused by nonsense mutations in a gene called family with sequence similarity 83 member H (FAM83H). To study the pathogenesis of ADHCAI, a Chinese ADHCAI family was investigated. MATERIALS AND METHODS: The ultrastructure of enamel was analyzed by micro-CT and scanning electron microscopy. Whole-exome sequencing (WES) was performed to identify the pathogenic gene. The function of the mutant FAM83H was studied by real-time PCR, western blotting, subcellular localization, and protein degradation pathway analyses. RESULTS: WES identified a known nonsense mutation (c.1915A > T) in exon 5 of the FAM83H gene, causing a truncated protein (p.Lys639*). However, the cases reported herein exhibited significant differences in the clinical phenotype compared with that the previously reported case. An abnormal enamel rod head structure was observed in affected teeth. In vitro functional studies showed altered protein localization and a decreased protein degradation rate for mutant FAM83H. CONCLUSIONS: We verified the FAM83H p.Lys639* protein as a gain-of-function variant causing ADHCAI. Abnormal enamel rod head structure was observed in teeth with mutant FAM83H proteins. We also investigated the molecular pathogenesis and presented data on the abnormal degradation of mutant FAM83H proteins. CLINICAL RELEVANCE: This study helped the family members to understand the disease progression and provided new insights into the pathogenesis of ADHCAI. Due to the large heterogeneity of ADHCAI, this study also provided a genetic basis for individuals who exhibit similar clinical phenotypes.

LncRNA FAM83H-AS1 promotes oesophageal squamous cell carcinoma progression via miR-10a-5p/Girdin axis.

Long non-coding RNAs (lncRNAs) have been well demonstrated to emerge as crucial regulators in cancer progression, and they can function as regulatory network based on their interactions. Although the biological functions of FAM83H-AS1 have been confirmed in various tumour progressions, the underlying molecular mechanisms of FAM83H-AS1 in oesophageal squamous cell carcinoma (ESCC) remained poorly understood. To address this, we treated human oesophageal cancer cell line Eca109 cells with TGF-ß and found FAM83H-AS1 was notably overexpressed. In the present study, FAM83H-AS1 was observed to be significantly up-regulated in ESCC tissues and was associated with TNM stage, pathological differentiation and lymph node metastasis. FAM83H-AS1 reinforced oesophageal cancer cell proliferation, migration and invasion, and participated in epithelial-to-mesenchymal transition (EMT) process at mRNA and protein levels. In addition, a concordant regulation between FAM83H-AS1 and its sense strand FAM83H was detected at the transcriptional and translational levels. Furthermore, FAM83H-AS1 could act as competing endogenous RNA to affect the expression of Girdin by sponging miR-10a-5p verified by RIP and luciferase reporter assays. Consequently, the study provided a unique perspective of FAM83H-AS1 in ESCC progression, which may be considered as potential biomarker and therapeutic target for ESCC therapy.

The clinical prognostic value of lncRNA FAM83H-AS1 in cancer patients: a meta-analysis.

BACKGROUND: Family with sequence similarity 83 member H antisense RNA 1 (FAM83H-AS1) is a novel long non-coding RNA. Increasing studies have reported that FAM83H-AS1 is abnormally expressed in a variety of tumors and is associated with poor outcome. However, the clinical prognostic significance of lncRNA FAM83H-AS1 in tumors is not completely known. METHODS: In this meta-analysis, literature was collected up until February 5, 2020 through multifarious retrieval strategies by searching through electronic databases of PubMed, Cochrane Library, EMBASE, Medline, Web of Science, CNKI, Weipu, and Wanfang. A total of 14 studies that met the inclusion criteria with relevant clinical data and prognostic information were included in the meta-analysis. RESULTS: The combined results revealed that high expression of FAM83H-AS1 was associated with poor overall survival (OS) (HR = 1.63, 95% CI 1.24-2.14, P = 0.0004) in a variety of cancers. Additionally, upregulated FAM83H-AS1 expression was significantly correlated with tumor TNM stage (III/IV vs. I/II, OR = 2.40, 95% CI 1.36-4.23, P = 0.003) and lymph node metastasis (positive vs. negative, OR = 1.70, 95% CI 1.14-2.52, P = 0.008) in patients with cancer. CONCLUSIONS: Our results of this meta-analysis indicated that elevated FAM83H-AS1 expression could predict poor prognosis in patients with cancer and suggested that FAM83H-AS1 might serve as a novel biomarker for cancer.

LncRNA FAM83H-AS1 induces nucleus pulposus cell growth via targeting the Notch signaling pathway.

Long noncoding RNA (lncRNA) represents a new group of transcripts which act a critical role in various biological and pathological processes. Growing evidence suggested that a new lncRNA, FAM83H-AS1, played important roles in several cancers. However, the underlying mechanisms of FAM83H-AS1-regulating functions in intervertebral disc degeneration (IDD) have yet to be explained. Thus study examined the role of lncRNA FAM83H-AS1 in progression of IDD. First, we proved that expression level of FAM83H-AS1 was expressed in nondegenerated nucleus pulposus (NP) tissues and degenerative NP samples. Moreover, we studied the expression level of FAM83H-AS1 relationship of the clinical disc degeneration grade. Our data suggested that FAM83H-AS1 expression was downregulated in normal NP samples compared with in the degenerated NP samples. FAM83H-AS1 expression was positively correlated with degree of disc degeneration grade. The expression of FAM83H-AS1 was positively correlated with scores of Pfirrmann grade. FAM83H-AS1 expression was increased by IL-1ß and TNF-αtreatment in NP cells. Ectopic expression of FAM83H-AS1 induced cell growth and modulated extracellular matrix (ECM) expression in the NP cell. Elevated expression of FAM83H-AS1 promoted Notch1 and Hes1 expression in NP cells. Furthermore, FAM83H-AS1 induced NP cell growth and modulated ECM expression through targeting Notch 1. To conclude, dysregulated expression of FAM83H-AS1 played a crucial role in progression of IDD.

FAM83H-AS1 is associated with clinical progression and modulates cell proliferation, migration, and invasion in bladder cancer.

FAM83H-AS1, also known as oncogenic long noncoding RNA (lncRNA)-3, is a novel lncRNA that has been suggested to be dysregulated in a variety of human cancers. However, the expression status and function of FAM83H-AS1 in bladder cancer are still unknown. The object of our study is to explore the clinical value of FAM83H-AS1 in patients with bladder cancer and the biological function of FAM83H-AS1 in bladder cancer cells. In our results, the expression of FAM83H-AS1 was obviously elevated in bladder cancer tissue samples and bladder cancer cell lines compared with adjacent normal tissue samples and normal bladder epithelial cell lines, respectively. In addition, high expression of FAM83H-AS1 was associated with advanced clinical stage and the presence of muscularis invasion and served as an independent poor prognostic factor for overall survival in patients with bladder cancer. The loss-of-function study showed that silencing FAM83H-AS1 expression suppressed cell proliferation, migration, and invasion and induced cycle arrest at G0/G1 phase. In conclusion, FAM83H-AS1 is involved in the progression of bladder cancer and serves as a prognostic biomarker and potential therapeutic target for patients with bladder cancer.

Long noncoding RNA FAM83H-AS1 exerts an oncogenic role in glioma through epigenetically silencing CDKN1A (p21).

Gliomas are the commonest and most aggressive primary malignant tumor in the central nervous system. Long noncoding RNAs (lncRNAs) have been identified to act as crucial regulators in multiple biological processes, including tumorigenesis. FAM83H antisense RNA1 (FAM83H-AS1) has been uncovered to be dysregulated in several cancers. However, the biological role of FAM83H-AS1 in glioma still needs to be investigated. Currently, our findings indicated that FAM83H-AS1 was upregulated in glioma tissues and cell lines and high level of FAM83H-AS1 was associated with poor prognosis of glioma. Loss-of-function assays demonstrated that silenced FAM83H-AS1 obviously suppressed cell proliferation via regulating the cell-cycle distribution and cell apoptosis rate, and mechanistic experiments revealed that FAM83H-AS1 could epidemically silence CDKN1A expression through recruiting EZH2 to the promoter of CDKN1A, thereby influencing the cell cycle and proliferation. Collectively, our findings suggested that FAM83H-AS1 participated in the progression of glioma and might act as a potential therapeutic target and prognosis biomarker for human glioma.

Fam83h mutation inhibits the mineralization in ameloblasts by activating Wnt/ß-catenin signaling pathway.

FAM83H was identified as the major causative gene for autosomal dominant hypocalcified amelogenesis imperfect (ADHCAI). The pathogenic mechanism of FAM83H in ADHCAI remains elusive. The present study aims to investigate the effect of Fam83h mutation on the mineralization of mouse ameloblast cell line LS8 and to explore the possible pathogenesis of ADHCAI. Lentivirus package was performed for the plasmids with mouse Fam83h mutant cDNA (c.1186C > T, M3) and empty vector (Control) and transfected into LS8, which were divided into M3-FLAG and Control groups. Immunoprecipitation, western-blot and immunofluorescence were performed to detect the expression and subcellular localization of Fam83 h, CK1α and ß-catenin. ALP activity, ALP staining, expression of the mineralization factors were detected in two groups during mineralization induction. Expression of the mineralization factors was also detected in M3-FLAG and LS8 exposing to pyrvinium pamoate. Compared with the Control, the Fam83h mutation altered the expression and localization of Fam83 h, CK1α and ß-catenin in LS8, inhibited the mineralization and down-regulated the expression of mineralization factors in M3-FLAG. Pyrvinium pamoate, an inhibitor of the Wnt/ß-catenin signaling pathway, up-regulated expression of mineralization factors in LS8 and rescued the inhibited mineralization in M3-FLAG. The results indicated that the Fam83h mutation could inhibit the mineralization in ameloblasts by activating Wnt/ß-catenin signaling pathway.

P38/JNK signaling pathway mediates the fluoride-induced down-regulation of Fam83h.

BACKGROUND/AIM: The similar clinical and pathological feature in fluorosis and amelogenesis imperfect with FAM83H mutations imply that excess fluoride could have effects on the expression of FAM83H and could elaborate this process by some signal pathways regulation. The present study aims to investigate the effects of fluoride on Fam83h expression and try to explore the molecular signaling regulation between them as well as the association of high concentration fluoride with mineralization in ameloblast lineage cells. METHODS: Protein expression and signaling pathways of mouse ameloblast-like LS8 cells, exposed to fluoride or MAPK inhibitors, were compared to control cells without exposure. Fam83h, proteins of MAPK signal pathways (ERK, P38 and JNK) were examined by Quantitative real-time PCR and/or Western-blot. ALP activity and ALP staining were used to detect the mineralization in the cells with exposure during 7-day mineralization inducing differentiation. RESULTS: The results showed that Fam83h protein level in LS8 cells decreased in the presence of fluoride and MAPK inhibitors. Down-regulation of Fam83h by fluoride was related to suppression of JNK and P38 phosphorylation, and the descending degree of P38 was more obvious. Fluoride and MAPK inhibitors treatment significantly decreased the mineralization level in LS8 cells. CONCLUSION: The findings suggest that JNK and P38 could be key regulatory element for Fam83h expression, and that LS8 cells can respond to fluoride by down-regulating Fam83h expression through the regulation of JNK and p38 signaling pathways.

A novel mechanism of keratin cytoskeleton organization through casein kinase Iα and FAM83H in colorectal cancer.

Keratin filaments form cytoskeletal networks in epithelial cells. Dynamic rearrangement of keratin filament networks is required for epithelial cells to perform cellular processes such as cell migration and polarization; however, the mechanism governing keratin filament rearrangement remains unclear. Here, we describe a novel mechanism of keratin cytoskeleton organization mediated by casein kinase Iα (CK-1α) and a newly identified keratin-associated protein, FAM83H. Knockdown of FAM83H induces keratin filament bundling, whereas overexpression of FAM83H disassembles keratin filaments, suggesting that FAM83H regulates the filamentous state of keratins. Intriguingly, keratin filament bundling is concomitant with the dissociation of CK-1α from keratin filaments, whereas aberrant speckle-like localization of CK-1α is observed concomitantly with keratin filament disassembly. Furthermore, CK-1α inhibition, similar to FAM83H knockdown, causes keratin filament bundling and reverses keratin filament disassembly induced by FAM83H overexpression, suggesting that CK-1α mediates FAM83H-dependent reorganization of keratin filaments. Because the N-terminal region of FAM83H interacts with CK-1α and the C-terminal region interacts with keratins, FAM83H might tether CK-1α to keratins. Colorectal cancer tissue also shows keratin filament disassembly accompanied with FAM83H overexpression and aberrant CK-1α localization, and FAM83H-overexpressing cancer cells exhibit loss or alteration of epithelial cell polarity. Importantly, knockdown of FAM83H inhibits cell migration accompanied by keratin cytoskeleton rearrangement in colorectal cancer cells. These results suggest that keratin cytoskeleton organization is regulated by FAM83H-mediated recruitment of CK-1α to keratins, and that keratin filament disassembly caused by overexpression of FAM83H and aberrant localization of CK-1α could contribute to the progression of colorectal cancer.

LncRNA FAM83H-AS1 Contributes to the Radio-resistance and Proliferation in Liver Cancer through Stability FAM83H Protein.

BACKGROUND: Liver cancer (LC) is one of China's most common malignant tumors, with a high mortality rate, ranking third leading cause of death after gastric and esophageal cancer. Recent patents propose the LncRNA FAM83H-AS1 has been verified to perform a crucial role in the progression of LC. LncRNA FAM83H-AS1 has been verified to perform a crucial role in the progression of LC. However, the concrete mechanism remains to be pending further investigation. OBJECTIVE: This study aimed to explore the embedding mechanism of FAM83H-AS1 molecules in terms of radio sensitivity of LC and provide potentially effective therapeutic targets for LC therapy. METHODS: Quantitative real-time PCR (qRT-PCR) was conducted to measure the transcription levels of genes. Proliferation was determined via CCK8 and colony formation assays. Western blot was carried out to detect the relative protein expression. A xenograft mouse model was constructed to investigate the effect of LncRNA FAM83H-AS1 on tumor growth and radio-sensitivity in vivo. RESULTS: The levels of lncRNA FAM83H-AS1 were remarkably increased in LC. Knockdown of FAM83H-AS1 inhibited LC cell proliferation and colony survival fraction. Deletion of FAM83H-AS1 increased the sensitivity of LC cells to 4 Gy of X-ray radiation. In the xenograft model, radiotherapy combined with FAM83H-AS1 silencing significantly reduced tumor volume and weight. Overexpression of FAM83H reversed the effects of FAM83H-AS1 deletion on proliferation and colony survival fraction in LC cells. Moreover, the over-expressing of FAM83H also restored the tumor volume and weight reduction caused by the knockdown of FAM83H-AS1 or radiation in the xenograft model. CONCLUSION: Knockdown of lncRNA FAM83H-AS1 inhibited LC growth and enhanced radiosensitivity in LC. It has the potential to be a promising target for LC therapy.

M6A-modified lncRNA FAM83H-AS1 promotes colorectal cancer progression through PTBP1.

LncRNA plays a crucial role in cancer progression and targeting, but it has been difficult to identify the critical lncRNAs involved in colorectal cancer (CRC) progression. We identified FAM83H-AS1 as a tumor-promoting associated lncRNA using 21 pairs of stage IV CRC tissues and adjacent normal tissues. In vitro and in vivo experiments revealed that knockdown of FAM83H-AS1 in CRC cells inhibited tumor proliferation and metastasis, and vice versa. M6A modification is critical for FAM83H-AS1 RNA stability through the writer METTL3 and the readers IGF2BP2/IGFBP3. PTBP1-an RNA binding protein-is responsible for the FAM83H-AS1 function in CRC. T4 (1770-2440 nt) and T5 (2440-2743 nt) on exon 4 of FAM83H-AS1 provide a platform for PTBP1 RRM2 interactions. Our results demonstrated that m6A modification dysregulated the FAM83H-AS1 oncogenic role by phosphorylated PTBP1 on its RNA splicing effect. In patient-derived xenograft models, ASO-FAM83H-AS1 significantly suppressed the growth of gastrointestinal (GI) tumors, not only CRC but also GC and ESCC. The combination of ASO-FAM83H-AS1 and oxaliplatin/cisplatin significantly suppressed tumor growth compared with treatment with either agent alone. Notably, there was pathological complete response in all these three GI cancers. Our findings suggest that FAM83H-AS1 targeted therapy would benefit patients primarily receiving platinum-based therapy in GI cancers.

FAM83H Expression Is Associated with Tumor-Infiltrating PD1-Positive Lymphocytes and Predicts the Survival of Breast Carcinoma Patients.

BACKGROUND: FAM83H has been implicated in cancer progression, and PD1 is an important target for anti-cancer immune checkpoint therapy. Recent studies suggest an association between FAM83H expression and immune infiltration. However, studies on the roles of FAM83H and its relationship with PD1 in breast carcinomas have been limited. METHODS: Immunohistochemical expression of FAM83H and PD1 and their prognostic significance were evaluated in 198 breast carcinomas. RESULTS: The expression of FAM83H in cancer cells was significantly associated with the presence of PD1-positive lymphoid cells within breast carcinoma tissue. Individual and co-expression patterns of nuclear FAM83H and PD1 were significantly associated with shorter survival of breast carcinomas in univariate analysis. In multivariate analysis, the expression of nuclear FAM83H (overall survival, p < 0.001; relapse-free survival, p = 0.003), PD1 (overall survival, p < 0.001; relapse-free survival, p = 0.003), and co-expression patterns of nuclear FAM83H and PD1 (overall survival, p < 0.001; relapse-free survival, p < 0.001) were the independent indicators of overall survival and relapse-free survival of breast carcinoma patients. CONCLUSIONS: This study suggests a close association between FAM83H expression and the infiltration of PD1-positive lymphoid cells in breast carcinomas and their expression as the prognostic indicators for breast carcinoma patients, and further studies are needed to clarify this relationship.

Fam83h mutation causes mandible underdevelopment via CK1α-mediated Wnt/ß-catenin signaling in male C57/BL6J mice.

Truncation mutations in FAM83H are the major cause of autosomal dominant hypocalcified amelogenesis imperfecta. Some studies also indicated that FAM83H could be involved in osteogenic differentiation; however, the function of FAM83H in bone formation was rarely explored. This study aimed to explore the effect of Fam83h mutation on skeletal development. We generated Fam83h c.1186C>T (p.Q396*) knockin C57/BL6J mice by CRISPR/Cas9 technology and found that the Fam83hQ396⁎/Q396⁎ male mice presented skeletal development retardation that was inconspicuous at birth but progressively worsened as they grew up. Alcian and Alizarin Red staining of the whole-mount skeleton showed Fam83hQ396⁎/Q396⁎ mice presented obvious skeletal development retardation. Moreover, Micro-computed tomography (Micro-CT) analysis and H&E staining showed that the mandible of Fam83hQ396⁎/Q396⁎ mice exhibited decreased bone trabecula and slight bone rarefaction compared with wild-type mice. Calcium and phosphorus content of serum and bone, and serum ALP activity analysis showed that the serum ALP activity and value of bone calcium were decreased in Fam83hQ396⁎/Q396⁎ mice. The reduced expression of mineralization markers of RUNX2, OSX, OCN, and COL1, the reduced ALP activity and the weakened ARS staining exhibited in osteoblasts isolated from 3-day-old Fam83hQ396⁎/Q396⁎ mice. The increased protein expression of casein kinase 1α (CK1α) in the cytoplasm and the decreased expression of ß-CATENIN in the nucleus indicated the inhibiting Wnt/ß-catenin signaling in osteoblasts from Fam83hQ396⁎/Q396⁎ mice. Furthermore, agonists of Wnt/ß-catenin signaling and Ck1α siRNA partially reversed the mineralization inhibition and the decreased expression of key signaling molecules in osteoblasts of Fam83hQ396⁎/Q396⁎ mice. In conclusion, Fam83h mutation caused the increase of cytoplasmic CK1α (as one of the components of the degradation complex), which in turn promoted degradation of ß-CATENIN in the cytoplasm and reduced ß-CATENIN translocation into the nucleus, subsequently inhibited Wnt/ß-catenin signaling in osteoblast differentiation, and thus resulted in the mandible underdevelopment in Fam83hQ396⁎/Q396⁎ male mice.

WTAP-Involved the m6A Modification of lncRNA FAM83H-AS1 Accelerates the Development of Gastric Cancer.

The long noncoding RNA FAM83H-antisense RNA 1 (FAM83H-AS1) is involved in gastric cancer (GC) development. This study determined whether FAM83H-AS1 was regulated by N6-methyladenosine (m6A) modifications in GC. Real-time quantitative polymerase chain reaction was performed to determine the expression levels of FAM83H-AS1 and Wilms' tumor 1 associated protein (WTAP). The protein content of WTAP was evaluated using western blotting. To assess the m6A alterations in FAM83H-AS1, methylated RNA immunoprecipitation was performed to identify interactions between WTAP and FAM83H-AS1. Functionally, the proliferation, migration, and invasion of GC cells were measured using a Cell Counting Kit-8 and transwell assays, respectively. High expression levels of FAM83H-AS1 and WTAP were detected in GC samples and there was a positive correlation between them. In addition, WTAP mediates FAM83H-AS1 expression in an m6A-dependent manner. Further investigations indicated that WTAP silencing reversed the cancer-promoting role of FAM83H-AS1 overexpression in GC cell migration, proliferation, and invasion. Our results suggest that WTAP-mediated FAM83H-AS1 promotes GC development via m6A modification. Our findings provide new biomarkers for GC diagnosis and targeted therapy. Wilms' tumor 1 associated protein (WTAP) promotes gastric cancer (GC) by accelerating cell proliferation, migration, and invasion of GC cells via the N6-methyladenosine(m6A) modification of long non coding RNA FAM83H-AS1.

A novel FAM83H variant causes familial amelogenesis imperfecta with incomplete penetrance.

BACKGROUND: Amelogenesis imperfecta (AI) is known to be a monogenic genetic disease caused by a variety of genes demonstrating a wide spectrum of penetrance. FAM83H is reported to be involved in AI: however, whether FAM83H causes AI with incomplete penetrance is unclear. METHODS: Whole-exome sequencing was performed on two patients with AI, and putative disease-related variants were validated by Sanger sequencing. Bioinformatic and in vitro functional analyses were performed to functionally characterize the identified disease-causing variants. RESULTS: We identified a novel heterozygous nonsense variant of FAM83H (NM_198488: c.1975G > T, p.Glu659Ter); in vitro functional analysis showed that this mutant produced mislocalized proteins and was deleterious. Surprisingly, the clinical manifestations of each of the six individuals carrying this variant were different, with one carrier appearing to be completely asymptomatic for AI. CONCLUSION: Our findings expand the variant spectrum for FAM83H and the phenotypic spectrum for FAM83H-associated AI and suggest that FAM83H-mediated AI exhibits incomplete penetrance.