KIF3A binds to β-arrestin for suppressing Wnt/β-catenin signalling independently of primary cilia in lung cancer

The complex relationship of Wnt-signaling pathways and cilia

Wnt family proteins are secreted glycolipoproteins that signal through multitude of signal transduction pathways. The Wnt-pathways are conserved and critical in all metazoans. They are essential for embryonic development, organogenesis and homeostasis, and associated with many diseases when defective or deregulated. Wnt signaling pathways comprise the canonical Wnt pathway, best known for its stabilization of β-catenin and associated nuclear β-catenin activity in gene regulation, and several non-canonical signaling branches. Wnt-Planar Cell Polarity (PCP) signaling has received the most attention among the non-canonical Wnt pathways. The relationship of cilia to Wnt-signaling is complex. While it was suggested that canonical Wnt signaling requires cilia this notion was always challenged by results suggesting the opposite. Recent developments provide insight and clarification to the relationship of Wnt signaling pathways and cilia. First, it has been now demonstrated that while ciliary proteins, in particular the IFT-A complex, are required for canonical Wnt/β-catenin signaling, the cilium as a structure is not. In contrast, recent work has defined a diverged canonical signaling branch (not affecting β-catenin) to be required for ciliary biogenesis and cilia function. Furthermore, the non-canonical Wnt-PCP pathway does not affect cilia biogenesis per se, but it regulates the position of cilia within cells in many cell types, possibly in all cells where it is active, with cilia being placed near the side of the cell that has the Frizzled-Dishevelled complex. This Wnt/PCP feature is conserved with both centrioles and basal bodies/cilia being positioned accordingly, and it is also used to align mitotic spindles within the Wnt-PCP polarization axis. It also coordinates the alignment of cilia in multiciliated cells. This article addresses these new insights and different links and relationships between cilia and Wnt signaling.

Ac-SDKP promotes KIF3A-mediated β-catenin suppression through a ciliary mechanism to constrain silica-induced epithelial-myofibroblast transition

Kinesin family member 3 A (KIF3A) decrease have been reported in silicotic patients and rats. However, the detailed mechanisms of KIF3A in silicosis remain unknown. In this study, we demonstrated that KIF3A effectively blocked the expression of β-catenin and downstream myocardin-related transcription factor (MRTF)-A/serum response factor (SRF) signaling, thus inhibiting silica-induced epithelial-myofibroblast transition (EMyT). Moreover, KIF3A was identified as a downstream mediator of an antifibrotic tetrapeptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP). Knockdown of KIF3A expression reactivated β-catenin/myocardin-related transcription factor (MRTF)-A/serum response factor (SRF) signaling that was attenuated by Ac-SDKP in vitro. Collectively, our findings suggest that Ac-SDKP plays its anti-fibrosis role via KIF3A-mediated β-catenin suppression, at least in part, in both in vivo model of silicosis and in vitro model of EMyT.

Kinesin family member 3A induces related diseases via wingless-related integration site/β-catenin signaling pathway

Kinesin family member 3A is an important motor protein that participates in various physiological and pathological processes, including normal tissue development, homeostasis maintenance, tumor infiltration, and migration. The wingless-related integration site/β-catenin signaling pathway is essential for critical molecular mechanisms such as embryonic development, organogenesis, tissue regeneration, and carcinogenesis. Recent studies have examined the molecular mechanisms of kinesin family member 3A, among which the wingless-related integration site/β-catenin signaling pathway has gained attention. The interaction between kinesin family member 3A and the wingless-related integration site/β-catenin signaling pathway is compact and complex but is fascinating and worthy of further study. The upregulation and downregulation of kinesin family member 3A influence many diseases and patient survival through the wingless-related integration site/β-catenin signaling pathway. Therefore, this review mainly focuses on describing the kinesin family member 3A and wingless-related integration site/β-catenin signaling pathways and their associated diseases.

Primary Cilia: The New Face of Craniofacial Research

The primary cilium is a solitary, sensory organelle that extends from the surface of nearly every vertebrate cell, including craniofacial cells. This organelle converts chemical and physical external stimuli into intracellular signaling cascades and mediates several well-known signaling pathways simultaneously. Thus, the primary cilium is considered a cellular signaling nexus and amplifier. Primary cilia dysfunction directly results in a collection of diseases and syndromes that typically affect multiple organ systems, including the face and teeth. Despite this direct connection, primary cilia are largely unexplored in craniofacial research. In this review, I briefly summarize craniofacial abnormalities tied to the primary cilium and examine the existing information on primary cilia in craniofacial development and repair. I close with a discussion on preliminary studies that motivate future areas of exploration that are further supported by studies performed in long bone and kidney cells.

KIF3A inhibits nasopharyngeal carcinoma proliferation, migration and invasion by interacting with β-catenin to suppress its nuclear accumulation

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor prevalent in southern China and Southeast Asia. Previous studies have shown that Kinesin Family Member 3A (KIF3A) plays a critical role in the oncogenesis of various cancer types. However, the role of KIF3A in NPC tumorigenesis and the mechanism underlying its function have not been reported. In this study, we found that KIF3A was significantly downregulated in NPC cells and tissues, and KIF3A expression in NPC patients was associated with tumor stage and was positively corrected with overall survival. In vitro and in vivo experiments indicated that overexpression of KIF3A inhibited NPC cell proliferation, migration, and invasion. Mechanistic studies found that KIF3A bound β-catenin and attenuated β-catenin aggregation in the nucleus. Moreover, rescue experiments demonstrated that the inhibitory effect of KIF3A on NPC proliferation, migration and invasion was partially dependent on β-catenin. Taken together, our data suggest that KIF3A interacts with β-catenin and attenuates NPC proliferation, migration, and invasion by suppressing the intranuclear aggregation of β-catenin. KIF3A may be a promising therapeutic target of patients with NPC.

Loss of KAP3 decreases intercellular adhesion and impairs intracellular transport of laminin in signet ring cell carcinoma of the stomach

Signet-ring cell carcinoma (SRCC) is a unique subtype of gastric cancer that is impaired for cell-cell adhesion. The pathogenesis of SRCC remains unclear. Here, we show that expression of kinesin-associated protein 3 (KAP3), a cargo adaptor subunit of the kinesin superfamily protein 3 (KIF3), a motor protein, is specifically decreased in SRCC of the stomach. CRISPR/Cas9-mediated gene knockout experiments indicated that loss of KAP3 impairs the formation of circumferential actomyosin cables by inactivating RhoA, leading to the weakening of cell-cell adhesion. Furthermore, in KAP3 knockout cells, post-Golgi transport of laminin, a key component of the basement membrane, was inhibited, resulting in impaired basement membrane formation. Together, these findings uncover a potential role for KAP3 in the pathogenesis of SRCC of the stomach.

Kinesin family member 3A stimulates cell proliferation, migration, and invasion of bladder cancer cells in vitro and in vivo

Bladder cancer is one of the most common malignant tumors of the urinary system, with high morbidity and mortality. At present, the survival rates and prognosis of patients with bladder cancer are still relatively low; thus, there remains a need to improve prognosis by identifying novel targets. Kinesins (kinesin superfamily proteins) are a series of microtubule-based motor proteins that mediate various types of cellular processes. Kinesin family member 3A (KIF3A) is critical for cytoplasm separation in mitosis, and it has been reported to be misexpressed in multiple types of cancer. However, its effects on the progression and development of bladder cancer remain unclear. Herein, we report that KIF3A is highly expressed in human bladder cancer. We identified a significant correlation between KIF3A and clinical features, including clinical stage (P = 0.047), pathological tumor status (P = 0.045), lymph node status (P = 0.041) and metastasis (P = 0.035). KIF3A expression was also correlated with poor prognosis of patients with bladder cancer. Our results further indicated that KIF3A ablation resulted in cell cycle arrest; blocked the proliferation, migration and invasion of bladder cancer cells in vitro; and restrained tumor growth in mice in a microtubule-dependent manner. In summary, our findings suggest that KIF3A is a potential therapeutic target for bladder cancer.

Primary Cilia Formation Does Not Rely on WNT/β-Catenin Signaling

Primary cilia act as crucial regulators of embryo development and tissue homeostasis. They are instrumental for modulation of several signaling pathways, including Hedgehog, WNT, and TGF-β. However, gaps exist in our understanding of how cilia formation and function is regulated. Recent work has implicated WNT/β-catenin signaling pathway in the regulation of ciliogenesis, yet the results are conflicting. One model suggests that WNT/β-catenin signaling negatively regulates cilia formation, possibly via effects on cell cycle. In contrast, second model proposes a positive role of WNT/β-catenin signaling on cilia formation, mediated by the re-arrangement of centriolar satellites in response to phosphorylation of the key component of WNT/β-catenin pathway, β-catenin. To clarify these discrepancies, we investigated possible regulation of primary cilia by the WNT/β-catenin pathway in cell lines (RPE-1, NIH3T3, and HEK293) commonly used to study ciliogenesis. We used WNT3a to activate or LGK974 to block the pathway, and examined initiation of ciliogenesis, cilium length, and percentage of ciliated cells. We show that the treatment by WNT3a has no- or lesser inhibitory effect on cilia formation. Importantly, the inhibition of secretion of endogenous WNT ligands using LGK974 blocks WNT signaling but does not affect ciliogenesis. Finally, using knock-out cells for key WNT pathway components, namely DVL1/2/3, LRP5/6, or AXIN1/2 we show that neither activation nor deactivation of the WNT/β-catenin pathway affects the process of ciliogenesis. These results suggest that WNT/β-catenin-mediated signaling is not generally required for efficient cilia formation. In fact, activation of the WNT/β-catenin pathway in some systems seems to moderately suppress ciliogenesis.

Ciliopathic micrognathia is caused by aberrant skeletal differentiation and remodeling

Ciliopathies represent a growing class of diseases caused by defects in microtubule-based organelles called primary cilia. Approximately 30% of ciliopathies are characterized by craniofacial phenotypes such as craniosynostosis, cleft lip/palate and micrognathia. Patients with ciliopathic micrognathia experience a particular set of difficulties, including impaired feeding and breathing, and have extremely limited treatment options. To understand the cellular and molecular basis for ciliopathic micrognathia, we used the talpid² (ta² ), a bona fide avian model for the human ciliopathy oral-facial-digital syndrome subtype 14. Histological analyses revealed that the onset of ciliopathic micrognathia in ta² embryos occurred at the earliest stages of mandibular development. Neural crest-derived skeletal progenitor cells were particularly sensitive to a ciliopathic insult, undergoing unchecked passage through the cell cycle and subsequent increased proliferation. Furthermore, whereas neural crest-derived skeletal differentiation was initiated, osteoblast maturation failed to progress to completion. Additional molecular analyses revealed that an imbalance in the ratio of bone deposition and resorption also contributed to ciliopathic micrognathia in ta² embryos. Thus, our results suggest that ciliopathic micrognathia is a consequence of multiple aberrant cellular processes necessary for skeletal development, and provide potential avenues for future therapeutic treatments.

Kinesin family member 3A inhibits the carcinogenesis of non-small cell lung cancer and prolongs survival

Kinesin family member 3A (KIF3A) plays a crucial role in the carcinogenesis of different types of human cancer. The present study aimed to identify the role of KIF3A in the carcinogenesis of non-small cell lung cancer (NSCLC). KIF3A protein expression was determined in 163 patients with NSCLC using immunohistochemistry staining. The prognosis of patients with NSCLC was determined using Kaplan-Meier survival and Cox regression analyses. The function of KIF3A on the carcinogenesis and metastasis of NSCLC was determined in vitro. Furthermore, a protein-protein interaction (PPI) network of KIF3A was constructed and the potential interacting molecules were identified using bioinformatic analysis. The protein expression levels of KIF3A were significantly lower in the NSCLC tissues compared with that in the adjacent tissues, and low KIF3A expression level was associated with unfavorable survival outcomes in patients with NSCLC. Furthermore, KIF3A knockdown increased proliferation, invasion and metastasis, and inhibited apoptosis of NSCLC cells. KIF3A was demonstrated to interact with intraflagellar transport 57 (IFT57) in the PPI network. In addition, validation analyses indicated that KIF3A mRNA expression levels were positively correlated with IFT57 mRNA expression levels in clinical NSCLC samples and NSCLC cell lines. Taken together, the results of the present study suggested that KIF3A is a key tumor suppressor gene for carcinogenesis and metastasis of NSCLC, it may also function as a biomarker and interacts with IFT57 in the progression of NSCLC.

Primary Ciliary Signaling in the Skin-Contribution to Wound Healing and Scarring

Primary cilia (PC) are solitary, post-mitotic, microtubule-based, and membrane-covered protrusions that are found on almost every mammalian cell. PC are specialized cellular sensory organelles that transmit environmental information to the cell. Signaling through PC is involved in the regulation of a variety of cellular processes, including proliferation, differentiation, and migration. Conversely, defective, or abnormal PC signaling can contribute to the development of various pathological conditions. Our knowledge of the role of PC in organ development and function is largely based on ciliopathies, a family of genetic disorders with mutations affecting the structure and function of PC. In this review, we focus on the role of PC in their major signaling pathways active in skin cells, and their contribution to wound healing and scarring. To provide comprehensive insights into the current understanding of PC functions, we have collected data available in the literature, including evidence across cell types, tissues, and animal species. We conclude that PC are underappreciated subcellular organelles that significantly contribute to both physiological and pathological processes of the skin development and wound healing. Thus, PC assembly and disassembly and PC signaling may serve as attractive targets for antifibrotic and antiscarring therapies.

Suppression of KIF3A inhibits triple negative breast cancer growth and metastasis by repressing Rb-E2F signaling and epithelial-mesenchymal transition

Triple negative breast cancer (TNBC) displays higher heterogeneity, stronger invasiveness, higher risk of metastasis and poorer prognosis compared with major breast cancer subtypes. KIF3A, a member of the kinesin family of motor proteins, serves as a microtubule-directed motor subunit and has been found to regulate early development, ciliogenesis and tumorigenesis. To explore the expression, regulation and mechanism of KIF3A in TNBC, 3 TNBC cell lines, 98 cases of primary TNBC and paired adjacent tissues were examined. Immunohistochemistry, real-time PCR, western blot, flow cytometry, short hairpin RNA (shRNA) interference, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation techniques, transwell assays, scratch tests, and xenograft mice models were used. We found that KIF3A was overexpressed in TNBC and such high KIF3A expression was also associated with tumor recurrence and lymph node metastasis. Silencing of KIF3A suppressed TNBC cell proliferation by repressing the Rb-E2F signaling pathway and inhibited migration and invasion by repressing epithelial-mesenchymal transition. The tumor size was smaller and the number of lung metastatic nodules was lower in KIF3A depletion MDA-MB-231 cell xenograft mice than in the negative control group. In addition, KIF3A overexpression correlated with chemoresistance. These results suggested that high expression of KIF3A in TNBC was associated with the tumor progression and metastasis.

Repression of lncRNA-SVUGP2 mediated by EZH2 contributes to the development of non-small cell lung cancer via brisking Wnt/β-catenin signal

To grab the possible impact of lncRNA-SVUGP2 in the biology and process of non-small cell lung cancer (NSCLC). Sixty paired NSCLC tumour and the adjacent non-tumour lung tissues were collected for detection of lncRNA-SVUGP2. lncRNA-SVUGP2 expression in NSCLC cells (SK-MES-1, A549, SPC-A1, and NCI-H1975) was also detected. lncRNA-SVUGP2 was overexpressed and depressed in A549 and H1975 cells, and the effects of lncRNA-SVUGP2 dysregulation on cell biological performances including viability, colony formation, apoptosis, migration and invasion were grabbed. Furthermore, the regulatory association of lncRNA-SVUGP2 vs. EZH2 in H1975 cells, as well as the association between lncRNA-SVUGP2 and Wnt/β-catenin pathway, was explored. lncRNA-SVUGP2 was depressed in NSCLC tissues and cells. Overexpression of lncRNA-SVUGP2 depressed proliferation, induced apoptosis, and suppressed migration and invasion of A549 and H1975 cells. In addition, lncRNA-SVUGP2 was repressed by EZH2 and was inversely correlated with EZH2 levels in H1975 cells. Repression of lncRNA-SVUGP2 potentially participated in the oncogenic function of EZH2. Besides, overexpression of lncRNA-SVUGP2 depressed the briskness of Wnt/β-catenin signal in H1975 cells. Our data reveal that lncRNA-SVUGP2 is under-expressed in NSCLC cells and the reduced expression of lncRNA-SVUGP2 may enhance the development and process of NSCLC by interacting with EZH2 and activating Wnt/β-catenin pathway.

Cellular signalling by primary cilia in development, organ function and disease

Primary cilia project in a single copy from the surface of most vertebrate cell types; they detect and transmit extracellular cues to regulate diverse cellular processes during development and to maintain tissue homeostasis. The sensory capacity of primary cilia relies on the coordinated trafficking and temporal localization of specific receptors and associated signal transduction modules in the cilium. The canonical Hedgehog (HH) pathway, for example, is a bona fide ciliary signalling system that regulates cell fate and self-renewal in development and tissue homeostasis. Specific receptors and associated signal transduction proteins can also localize to primary cilia in a cell type-dependent manner; available evidence suggests that the ciliary constellation of these proteins can temporally change to allow the cell to adapt to specific developmental and homeostatic cues. Consistent with important roles for primary cilia in signalling, mutations that lead to their dysfunction underlie a pleiotropic group of diseases and syndromic disorders termed ciliopathies, which affect many different tissues and organs of the body. In this Review, we highlight central mechanisms by which primary cilia coordinate HH, G protein-coupled receptor, WNT, receptor tyrosine kinase and transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP) signalling and illustrate how defects in the balanced output of ciliary signalling events are coupled to developmental disorders and disease progression.

Regulation Mechanism of Long Noncoding RNAs in Colon Cancer Development and Progression

Colorectal cancer (CRC) is the second most common cause of cancer-related death worldwide, and its high rates of relapse and metastasis are associated with a poor prognosis. Despite extensive research, the underlying regulatory mechanisms of CRC remain unclear. Long noncoding RNAs (lncRNAs) are a major type of noncoding RNAs that have received increasing attention in the past few years, and studies have shown that they play a role in many biological processes in CRC. Here, we summarize recent studies on lncRNAs associated with CRC and the signaling pathways and mechanisms underlying this association. We show that dysregulated lncRNAs may be new prognostic and diagnostic biomarkers or therapeutic targets for clinical application. This review contributes not only to our understanding of CRC, but also suggests novel signaling pathways associated with lncRNAs that can be targeted to block or eradicate CRC.

Tubastatin A, an inhibitor of HDAC6, enhances temozolomide‑induced apoptosis and reverses the malignant phenotype of glioblastoma cells

Glioblastoma or grade IV astrocytoma is the most common and lethal form of glioma. Current glioblastoma treatment strategies use surgery followed by chemotherapy with temozolomide. Despite this, numerous glioblastoma cases develop resistance to temozolomide treatments, resulting in a poor prognosis for the patients. Novel approaches are being investigated, including the inhibition of histone deacetylase 6 (HDAC6), an enzyme that deacetylates α‑tubulin, and whose overexpression in glioblastoma is associated with the loss of primary cilia. The aim of the present study was to treat glioblastoma cells with a selective HDAC6 inhibitor, tubastatin A, to determine if the malignant phenotype may be reverted. The results demonstrated a notable increase in acetylated α‑tubulin levels in treated cells, which associated with downregulation of the sonic hedgehog pathway, and may hypothetically promote ciliogenesis in those cells. Treatment with tubastatin A also reduced glioblastoma clonogenicity and migration capacities, and accelerated temozolomide‑induced apoptosis. Finally, HDAC6 inhibition decreased the expression of mesenchymal markers, contributing to reverse epithelial‑mesenchymal transition in glioblastoma cells.

The association between methylation patterns of DNAH17 and clinicopathological factors in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a malignancy with poor prognosis. Complex genetic and epigenetic alterations are the two primary causes of HCC. The aim of the study was mainly to explore the correlation between the methylation status of DNAH17 and HCC.

Methods

We evaluated the methylation levels of DNAH17 in 163 HCC samples and their paired normal tissue using Sequenom EpiTYPER assays and performed the TaqMan copy number assay to assess the copy number status of DNAH17 in HCC samples.

Results

The mean methylation levels were significantly decreased in the tumor tissues compared to the paired normal tissues in both selected regions of DNAH17 (amplicon 1:58.7% vs 84.5%, P < 0.0001; amplicon 2:69.9% vs 84.5%, P = 0.0060). Contrarily，both RNA‐seq and immunohistochemistry indicated the expression of DNAH17 was increased in tumor tissues (P < 0.05). DNMT inhibitor decitabine treatment could increase the expression of DNAH17 in HCC cell lines. DNAH17 gene amplification always companied with hypomethylation status. Moreover, hypomethylation status was associated with several clinical characteristics, such as male patients, higher AFP values, higher age of onset, fibrous capsules, tumor necrosis, liver cirrhosis, and tumor thrombus (P < 0.05). Receiver operator characteristic (ROC) curve analysis demonstrated the methylation levels of DNAH17 could efficiently predict the existence of the fibrous capsule (AUC = 0.695) and tumor thrombus (AUC = 0.806).

Conclusions

These findings suggested that aberrant methylation of DNAH17 was associated with comprehensive HCC clinicopathological factors and could be a promising biomarker for tumor thrombosis in HCC patients.

Overexpression of CD300A inhibits progression of NSCLC through downregulating Wnt/β-catenin pathway

Background

CD300A, a type I transmembrane glycoprotein receptor, plays an important role in immune response. Recent studies have reported that CD300A is involved in the development of hematological malignancies.

Purpose

The objective of this study was to investigate the role of CD300A in the progression of non-small-cell lung cancer (NSCLC) and explore the associated mechanism.

Materials and methods

Gene Expression Profiling Interactive Analysis (GEPIA) was used to analyze the expression of CD300A in NSCLC and its prognostic value. NSCLC cell lines A549 and H1650 were transfected with siRNA-CD300A or pcDNA3.1-CD300A vector to down- or up-regulate the expression of CD300A. Cell Counting Kit 8, colony formation and Transwell assays were used to assess the effects of CD300A on cell proliferation and migration capacities. Flow cytometry was performed to examine rate of apoptosis, and the protein levels of associated proteins was detected using Western blot assay.

Results

From GEPIA analysis, we observed that expression of CD300A mRNA was downregulated in NSCLC and positively correlated with the overall survival of NSCLC patients. Overexpression of CD300A significantly suppressed cell growth and migration capacities of A549 and H1650 cells and induced cell apoptosis via regulating apoptosis-related proteins. Moreover, decreasing level of CD300A promoted cell growth and migration and blocked apoptosis of NSCLC cells. Furthermore, upregulation of CD300A led to significant decrease in expression level of Wnt3 and β-catenin, the pivotal components in Wnt/β-catenin signaling pathway, and an increase in expression of E-cad, a key protein in tumor metastasis, in A549 and H1650 cells; while depletion of CD300A up-regulated the Wnt/β-catenin signaling pathway. In conclusion, the present study highlighted an anti-oncogenic role of CD300A in the progression of NSCLC via inhibiting Wnt/β-catenin pathway, suggesting that CD300A might be a potential target for the treatment of NSCLC

Conclusion

CD300A plays an anti-oncogenic role in the progression of NSCLC through inhibiting the Wnt/β-catenin pathway, suggesting that CD300A might be a potential target for the treatment of NSCLC.

LRP16 prevents hepatocellular carcinoma progression through regulation of Wnt/β-catenin signaling

Elevated LRP16 expression is associated with poor clinical outcomes in multiple malignancies. We detected LRP16 expression in hepatocellular carcinoma (HCC) and found that it was downregulated in tumor samples and HCC cell lines. In a cohort of 80 HCC patients, high level of LRP16 expression in HCC tumors was associated with well differentiation, less lymph node metastasis, and good overall survival (OS). Overexpression of LRP16 in the HepG2 and MHCC-97L cell lines increased cell apoptosis, attenuated cell proliferation, migration, and invasion ability in vitro, and drastically diminished tumor growth and metastasis in vivo. Silencing LRP16 in HCC-LM3 and SMMC-7721 cell lines showed opposite results. Microarray evaluation of tumor cells overexpressing LRP16 revealed the effects on decreased activity in the Wnt signaling pathway. These results were confirmed by qRT-PCR and Western blots. Furthermore, inhibition of Wnt signaling decreased proliferation, migration, and invasion of HCC cell lines. Mechanism conducted showed that LRP16 overexpression could prevent β-catenin from entering the nucleus. Our study demonstrated that LRP16 suppresses tumor growth in HCC by modulating Wnt/β-catenin signaling.

KEY MESSAGES

LRP16 was low expression in HCC tissue and cell lines. Low expression of LRP16 in HCC was associated with poor prognosis. LRP16 inhibits activation of the Wnt/β-catenin pathway in HCC. LRP16 prevents β-catenin from entering the nucleus.

βArrestin2 Mediates Renal Cell Carcinoma Tumor Growth

Renal Cell Carcinoma (RCC) is one of the most lethal urological cancers worldwide. The disease does not present early clinical symptoms and is commonly diagnosed at an advanced stage. Limited molecular drivers have been identified for RCC, resulting in the lack of effective treatment for patients with progressive disease. Ubiquitous βArrestin2 (βArr2) is well established for its function in the desensitization and trafficking of G protein-coupled receptors. More recently, βArr2 has been implicated in the regulation of fundamental cellular functions, including proliferation and invasion. We used bioinformatic and genetic approaches to determine role of βArr2 in RCC tumor growth. Analysis of published human datasets shows that ARRB2 (gene encoding βArr2) expression is increased in RCC tumor compared to normal tissue and that high levels of ARRB2 correlate with worse patient survival. Experimentally, we show that knockout of ARRB2 decreases rate of RCC cell proliferation and migration in vitro and xenograft tumor growth in animals. Mechanistically, βArr2 regulates c-Src activity, Cyclin A expression and cell cycle progression that are involved in tumor growth. These results show that βArr2 is a critical regulator of RCC tumor growth and suggest its utility as a potential marker and drug target to treat advanced disease.

Sending mixed signals: Cilia-dependent signaling during development and disease

Molecular signals are the guiding force of development, imparting direction upon cells to divide, migrate, differentiate, etc. The mechanisms by which a cell can receive and transduce these signals into measurable actions remains a 'black box' in developmental biology. Primary cilia are ubiquitous, microtubule-based organelles that dynamically extend from a cell to receive and process molecular and mechanical signaling cues. In the last decade, this organelle has become increasingly intriguing to the research community due to its ability to act as a cellular antenna, receive and transduce molecular stimuli, and initiate a cellular response. In this review, we discuss the structure of primary cilia, emphasizing how the ciliary components contribute to the transduction of signaling pathways. Furthermore, we address how the cilium integrates these signals and conveys them into cellular processes such as proliferation, migration and tissue patterning. Gaining a deeper understanding of the mechanisms used by primary cilia to receive and integrate molecular signals is essential, as it opens the door for the identification of therapeutic targets within the cilium that could alleviate pathological conditions brought on by aberrant molecular signaling.

High expression of KIF3A is a potential new parameter for the diagnosis and prognosis of breast cancer

Kinesin Family Member 3A (KIF3A) was recognized as a key factor of ciliogenesis and transport system of primary cilia in normal cells. However, its possible function on cancer cells has yet to be identified. In the present study, microarray tissue chips, including 230 breast cancer samples, were applied to determine the KIF3A expression pattern by immunological histological chemistry. Statistical analysis on the KIF3A expression level and the currently used clinicopathological characteristics of breast cancer patients was carried out. Follow-up data of these patients over 10 years were also used to evaluate the relationship between KIF3A and the survival rate. The expression levels of KIF3A were significantly higher in 140 breast cancer tissues than those of 90 para-carcinoma samples, which served as controls (P<0.001). In addition, in a further 70 paired samples, the same higher expression level was observed in cancer tissues compared with their self-paired controls (P<0.001). Furthermore, the high expression of KIF3A in breast cancer tissue correlated with the status of estrogen receptor, androgen receptor, epidermal growth factor receptor and Ki-67 of breast cancer patients, and were also related to their pathology grade and lymph node metastasis. The survival analysis showed a better survival rate in the patients with a higher expression level of KIF3A. Collectively, the triadic associations of KIF3A, the currently used clinicopathological parameters and survival rate suggest that KIF3A is involved in the tumorigenesis and progression of breast cancer. Thus, KIF3A could be considered a promising novel prognostic index in breast cancer.

Reciprocal control of lncRNA-BCAT1 and β-catenin pathway reveals lncRNA-BCAT1 long non-coding RNA acts as a tumor suppressor in colorectal cancer

β-catenin plays a major role in tumor development and progression. The present study found that β-catenin was upregulated in 30 samples of colorectal cancer (CRC) tissue as compared to adjacent non-tumor tissues. Analysis of long non-coding RNA (lncRNA) expression profiles using the GSE18560 and GSE44097 datasets, which were generated via the Affymetrix plus 2.0 microarray platform and downloaded from the GEO database, revealed 20 differentially expressed lncRNAs following β-catenin knockdown. We focused on AK091631, a novel lncRNA, which we named lncRNA-β-catenin associated transcript 1 (LncRNA-BCAT1). lncRNA-BCAT1 expression was decreased in CRC tissues, and was negatively associated with β-catenin in both CRC tissues and cell lines. lncRNA-BCAT1 overexpression suppressed CRC cell growth and invasion by downregulating cyclin D1, c-Myc, and MMP-2. These results suggest that lncRNA-BCAT1 overexpression inhibits CRC cell growth and invasion via Wnt/β-catenin pathway blockade, and that lncRNA-BCAT1 is repressed by Wnt/β-catenin signaling. This evidence suggests that lncRNA-BCAT1 is a tumor suppressor and that lncRNA-BCAT1 may be an effective prognostic biomarker in CRC.

Primary Cilium-Dependent Signaling Mechanisms

Primary cilia are hair-like organelles and play crucial roles in vertebrate development, organogenesis, health, and many genetic disorders. A primary cilium is a mechano-sensory organelle that responds to mechanical stimuli in the micro-environment. A cilium is also a chemosensor that senses chemical signals surrounding a cell. The overall function of a cilium is therefore to act as a communication hub to transfer extracellular signals into intracellular responses. Although intracellular calcium has been one of the most studied signaling messengers that transmit extracellular signals into the cells, calcium signaling by various ion channels remains a topic of interest in the field. This may be due to a broad spectrum of cilia functions that are dependent on or independent of utilizing calcium as a second messenger. We therefore revisit and discuss the calcium-dependent and calcium-independent ciliary signaling pathways of Hedgehog, Wnt, PDGFR, Notch, TGF-β, mTOR, OFD1 autophagy, and other GPCR-associated signaling. All of these signaling pathways play crucial roles in various cellular processes, such as in organ and embryonic development, cardiac functioning, planar cell polarity, transactivation, differentiation, the cell cycle, apoptosis, tissue homeostasis, and the immune response.

Upregulation of miR-3607 promotes lung adenocarcinoma proliferation by suppressing APC expression

Lung cancer is the leading cause of worldwide cancer-related deaths, although many drugs and new therapeutic approaches have been used, the 5-years survival rate is still low for lung cancer patients. microRNAs have been shown to regulate lung cancer initiation and development, here we studied the role of miR-3607 in lung cancer cell proliferation. We found miR-3607 was upregulated in lung cancer tissues and cells, miR-3607 overexpression promoted lung cancer cell A549 proliferation determined by MTT assay, colony formation assay, anchorage-independent growth ability assay and bromodeoxyuridine incorporation assay, while the opposite phenotypes were shown when miR-3607 was knocked down. Predicted analysis suggested a Wnt signaling pathway regulator adenomatous polyposis coli (APC) was the target of miR-3607, miR-3607 could directly bind to the 3'UTR of APC, and promoted Cyclin D1 and c-Myc expression which can be suppressed by APC. Double knockdown of miR-3607 and APC copied the phenotypes of miR-3607 overexpression, suggesting miR-3607 promoted lung cancer cell A549 proliferation by targeting APC. In conclusion, our study suggested miR-3607 contributes to lung cancer cell proliferation by inhibiting APC.

The connections of Wnt pathway components with cell cycle and centrosome: side effects or a hidden logic?

Wnt signaling cascade has developed together with multicellularity to orchestrate the development and homeostasis of complex structures. Wnt pathway components - such as β-catenin, Dishevelled (DVL), Lrp6, and Axin-- are often dedicated proteins that emerged in evolution together with the Wnt signaling cascade and are believed to function primarily in the Wnt cascade. It is interesting to see that in recent literature many of these proteins are connected with cellular functions that are more ancient and not limited to multicellular organisms - such as cell cycle regulation, centrosome biology, or cell division. In this review, we summarize the recent literature describing this crosstalk. Specifically, we attempt to find the answers to the following questions: Is the response to Wnt ligands regulated by the cell cycle? Is the centrosome and/or cilium required to activate the Wnt pathway? How do Wnt pathway components regulate the centrosomal cycle and cilia formation and function? We critically review the evidence that describes how these connections are regulated and how they help to integrate cell-to-cell communication with the cell and the centrosomal cycle in order to achieve a fine-tuned, physiological response.

Quaking-5 suppresses aggressiveness of lung cancer cells through inhibiting β-catenin signaling pathway

Quaking-5 (QKI-5) belongs to the STAR (signal transduction and activation of RNA) family of RNA binding proteins and functions as a tumor suppressor in several human malignancies. In this study, we attempt to elucidate the role of QKI-5 in the pro-metastasis processes of lung cancer (LC) cells and the underlying mechanisms. We confirmed that QKI-5 was decreased in human LC tissues and cell lines, especially in high-metastatic cells. Moreover, QKI expression was positively correlated with LC patients’ survival. Functional studies verified that QKI-5 suppressed migration, invasion and TGF-β1-induced epithelial-mesenchymal transition (EMT) of LC cells. Mechanistically, we affirmed that QKI-5 reduced β-catenin level in LC cells via suppressing its translation and promoting its degradation, whereas QKI-5 promoter hypermethylation suppressed QKI-5 expression. Our findings indicate that QKI-5 inhibits pro-metastasis processes of LC cells through interdicting β-catenin signaling pathway, and that QKI-5 promoter hypermethylation is a crucial epigenetic regulation reducing QKI-5 expression in LC cells, and reveal that QKI-5 is a potential prognostic biomarker for LC patients.

Phospholipase Cδ1 suppresses cell migration and invasion of breast cancer cells by modulating KIF3A-mediated ERK1/2/β- catenin/MMP7 signalling

Phospholipase C δ1 (PLCD1) encodes an enzyme involved in energy metabolism, calcium homeostasis and intracellular movement. It is located at 3p22 in a region that is frequently deleted in multiple cancers, and the PLCD1 enzyme is a potential tumour suppressor in breast cancer that inhibits matrix metalloprotease (MMP) 7, but the detailed mechanism remains elusive. In this study, we found that PLCD1 was downregulated in breast cancers, and the gain-or-loss functional assay revealed that PLCD1 inhibited cell migration and invasion in vitro via the ERK1/2/β-catenin/MMP7 signalling pathway. Furthermore, KIF3A was identified as a downstream mediator of PLCD1, and there was an inverse correlation between the expression of PLCD1 and KIF3A. Knockdown of KIF3A expression alone suppressed cell migration and invasion, and attenuated ERK1/2/β-catenin/MMP7 signalling that was reactivated by knocking down PLCD1 in vitro. Collectively, our findings suggest that PLCD1 acts as a tumour suppressor, by KIF3A-mediated suppression of ERK1/2/β-catenin/MMP7 signalling, at least in part, in breast cancer.

Zinc suppresses stem cell properties of lung cancer cells through protein kinase C-mediated β-catenin degradation

Highly tumorigenic cancer stem cells (CSCs) residing in most cancers are responsible for cancer progression and treatment failure. Zinc is an element regulator of several cell functions; however, its role in regulation of stem cell program in lung cancer has not been demonstrated. The present study reveals for the first time that zinc can suppress stem cell properties of lung cancer cells. Such findings were proved in different lung cancer cell lines (H460, H23, and H292) and it was found that CSC markers (CD133 and ALDH1A1), stem cell-associated transcription factors (Oct4, Nanog, and Sox-2), and the ability to form tumor spheroid were dramatically suppressed by zinc treatments. Zinc was found to activate protein kinase C-α (PKCα) that further phosphorylated and mediated β-catenin degradation through the ubiquitin-proteasomal pathway. Zinc was found to increase the β-catenin-ubiquitin complex, which can be inhibited by a specific PKC inhibitor, bisindolylmaleimide I. Using specific reactive oxygen species detection and antioxidants, we have demonstrated that superoxide anions generated by zinc are a key upstream mechanism for PKCα activation leading to the subsequent suppression of stem cell features of lung cancer. Zinc increased cellular superoxide anions and the addition of superoxide anion scavenger prevented the activation of PKCα and β-catenin degradation. These findings indicate a novel role for zinc regulation in the PKCα/β-catenin pathway and explain an important mechanism for controlling of stem cell program in lung cancer cells.