WWC3 downregulation correlates with poor prognosis and inhibition of Hippo signaling in human gastric cancer

An integrative pan-cancer analysis of WWC family genes and functional validation in lung cancer

The WW and C2 domain containing (WWC) protein family functions as scaffolds regulating cell proliferation and organ growth control through the Hippo signaling pathway. However, their pan-cancer dysregulation and mechanistic roles in signaling transduction have remained unclear. We performed integrated pan-cancer analyses of WWC family gene expression using data from The Cancer Genome Atlas (TCGA) across 33 different cancer types. Prognostic relevance was evaluated by survival analyses. WWC genetic alterations, DNA methylation, pathway activities, drug response, and tumor immunology were analyzed using online databases. Furthermore, we examined the functional roles of WWCs in lung cancer cells. We observed aberrant WWC expression in various cancers, which associated with patient prognosis. WWC hypermethylation occurred in many cancers and exhibited negative correlation with expression, alongside mutations linked to poor outcomes. Pathway analysis implicated WWCs as Hippo pathway scaffolds, while drug sensitivity analysis suggested associations with diverse chemotherapies. Additionally, pan-cancer analyses elucidated vital immunomodulatory roles for WWC through heterogeneous correlations with immune cell infiltrates, checkpoint molecules, tumor mutation burden, microsatellite instability, and chemokine pathways across cancers. Experimentally, WWCs suppressed lung cancer cell proliferation, migration, and invasion while enhancing apoptosis and paclitaxel chemosensitivity. Mechanistically, WWCs bound large tumor suppressor 1 and 2 (LATS1/2) kinases to stimulate phosphorylation cascades, thereby inhibiting nuclear translocation of the Yes-associated protein (YAP) oncoprotein. Taken together, our multi-omics characterization provides comprehensive evidence for WWCs as putative tumor suppressors across cancers via Hippo pathway modulation. WWCs may serve as prognostic markers and therapeutic targets in lung cancer.

Loss of TTC17 promotes breast cancer metastasis through RAP1/CDC42 signaling and sensitizes it to rapamycin and paclitaxel

BACKGROUND

Breast cancer (BC) metastasis is the leading cause of poor prognosis and therapeutic failure. However, the mechanisms underlying cancer metastasis are far from clear.

METHODS

We screened candidate genes related to metastasis through genome-wide CRISPR screening and high-throughput sequencing of patients with metastatic BC, followed by a panel of metastatic model assays. The effects of tetratricopeptide repeat domain 17 (TTC17) on migration, invasion, and colony formation ability together with the responses to anticancer drugs were investigated in vitro and in vivo. The mechanism mediated by TTC17 was determined by RNA sequencing, Western blotting, immunohistochemistry, and immunofluorescence. The clinical significance of TTC17 was evaluated using BC tissue samples combined with clinicopathological data.

RESULTS

We identified the loss of TTC17 as a metastasis driver in BC, and its expression was negatively correlated with malignancy and positively correlated with patient prognosis. TTC17 loss in BC cells promoted their migration, invasion, and colony formation capacity in vitro and lung metastasis in vivo. Conversely, overexpressing TTC17 suppressed these aggressive phenotypes. Mechanistically, TTC17 knockdown in BC cells resulted in the activation of the RAP1/CDC42 pathway along with a disordered cytoskeleton in BC cells, and pharmacological blockade of CDC42 abolished the potentiation of motility and invasiveness caused by TTC17 silencing. Research on BC specimens demonstrated reduced TTC17 and increased CDC42 in metastatic tumors and lymph nodes, and low TTC17 expression was linked to more aggressive clinicopathologic characteristics. Through screening the anticancer drug library, the CDC42 inhibitor rapamycin and the microtubule-stabilizing drug paclitaxel showed stronger inhibition of TTC17-silenced BC cells, which was confirmed by more favorable efficacy in BC patients and tumor-bearing mice receiving rapamycin or paclitaxel in the TTC17^Low arm.

CONCLUSIONS

TTC17 loss is a novel factor promoting BC metastasis, that enhances migration and invasion by activating RAP1/CDC42 signaling and sensitizes BC to rapamycin and paclitaxel, which may improve stratified treatment strategies under the concept of molecular phenotyping-based precision therapy of BC.

Proteomics analysis of chronic skin injuries caused by mustard gas

Sulfur mustard (SM) is an alkylating and forming chemical that was widely used by Iraqi forces during the Iran–Iraq wars. One of the target organs of SM is the skin. Understanding the mechanisms involved in the pathogenesis of SM may help better identify complications and find appropriate treatments. The current study collected ten SM-exposed patients with long-term skin complications and ten healthy individuals. Proteomics experiments were performed using the high-efficiency TMT10X method to evaluate the skin protein profile, and statistical bioinformatics methods were used to identify the differentially expressed proteins. One hundred twenty-nine proteins had different expressions between the two groups. Of these 129 proteins, 94 proteins had increased expression in veterans' skins, while the remaining 35 had decreased expression. The hub genes included RPS15, ACTN1, FLNA, HP, SDHC, and RPL29, and three modules were extracted from the PPI network analysis. Skin SM exposure can lead to oxidative stress, inflammation, apoptosis, and cell proliferation.

Antitumor Activity of lncRNA NBAT-1 via Inhibition of miR-4504 to Target to WWC3 in Oxaliplatin-Resistant Colorectal Carcinoma

Background

Increasing evidence shows that dysfunction of noncoding RNAs is implicated in cancer. Neuroblastoma associated transcript 1 (NBAT-1) has been identified as a tumor suppressive lncRNA that is aberrantly expressed in cancers. However, the function and the underlying mechanisms of the NBAT-1 in colorectal carcinoma (CRC) remain unknown.

Methods

Gene expression was detected by RT-qPCR. The influence of NBAT-1 on CRC was evaluated by the cell counting kit-8 (CCK-8) assay and an in vivo xenograft mouse model. The possible binding of NBAT-1 to miRNAs was predicted via the miRDB online tool and confirmed by a dual-luciferase reporter assay. Protein expression was detected by western blot.

Results

NBAT-1 expression was significantly decreased in CRC tissues, especially in patients with oxaliplatin (OXA) resistance. NBAT-1 inhibited OXA-resistant CRC cell proliferation in vitro and tumor growth in vivo. The mechanism study revealed that NBAT-1 functioned as a competing endogenous RNA (ceRNA) of miR-4504. NBAT-1 bound miR-4504 and decreased miR-4504 expression in CRC cells. Furthermore, WW-and-C2-domain-containing protein family member 3 (WWC3) was identified as a target of miR-4504. Downregulation of NBAT-1 promoted miR-4504 expression and reduced the level of WWC3. Inhibition of WWC3 by NBAT-1 depletion inactivated Hippo signalling by inhibiting the phosphorylation of large tumor suppressor kinase 1 (LATS1) and yes-associated protein (YAP). Consistently, knockdown of NBAT-1 suppressed the expression of YAP transcriptional targets.

Conclusions

These findings demonstrated that lncRNA NBAT-1 suppresses OXA-resistant CRC cell growth via inhibition of miR-4504 to regulate the WWC3/LATS1/YAP axis.

WWC Proteins: Important Regulators of Hippo Signaling in Cancer

Simple Summary

The conserved Hippo pathway regulates cell proliferation and apoptosis via a complex interplay of transcriptional activities, post-translational protein modifications, specific protein–protein interactions and cellular transport processes. Deregulating this highly balanced system can lead to hyperproliferation, organ overgrowth and cancer. Although WWC proteins are known as components of the Hippo signaling pathway, their association with tumorigenesis is often neglected. This review aims to summarize the current knowledge on WWC proteins and their contribution to Hippo signaling in the context of cancer.

Abstract

The Hippo signaling pathway is known to regulate cell differentiation, proliferation and apoptosis. Whereas activation of the Hippo signaling pathway leads to phosphorylation and cytoplasmic retention of the transcriptional coactivator YAP, decreased Hippo signaling results in nuclear import of YAP and subsequent transcription of pro-proliferative genes. Hence, a dynamic and precise regulation of the Hippo signaling pathway is crucial for organ size control and the prevention of tumor formation. The transcriptional activity of YAP is controlled by a growing number of upstream regulators including the family of WWC proteins. WWC1, WWC2 and WWC3 represent cytosolic scaffolding proteins involved in intracellular transport processes and different signal transduction pathways. Earlier in vitro experiments demonstrated that WWC proteins positively regulate the Hippo pathway via the activation of large tumor suppressor kinases 1/2 (LATS1/2) kinases and the subsequent cytoplasmic accumulation of phosphorylated YAP. Later, reduced WWC expression and subsequent high YAP activity were shown to correlate with the progression of human cancer in different organs. Although the function of WWC proteins as upstream regulators of Hippo signaling was confirmed in various studies, their important role as tumor modulators is often overlooked. This review has been designed to provide an update on the published data linking WWC1, WWC2 and WWC3 to cancer, with a focus on Hippo pathway-dependent mechanisms.

Interaction of BACH2 with FUS promotes malignant progression of glioma cells via the TSLNC8-miR-10b-5p-WWC3 pathway

Glioma, a common malignant tumour of the human central nervous system, has poor prognosis and limited treatment options. Dissecting the biological mechanisms underlying glioma pathogenesis can facilitate the development of better therapies. Here, we investigated the endogenous expression of BTB and CNC homolog 2 (BACH2), fused in sarcoma (FUS), TSLNC8 and microRNA (miR)‐10b‐5p in glioma cells and tissues. We studied the interaction between BACH2 and FUS and its contribution to glioma progression. We demonstrated that the interaction between BACH2 and FUS promoted glioma progression via transcriptional inhibition of TSLNC8. Overexpression of TSLNC8 restrained glioma progression by suppressing miR‐10b‐5p. Binding of TSLNC8 to miR‐10b‐5p attenuated the suppression of WWC family member 3 (WWC3) by miR‐10b‐5p and activated the Hippo signalling pathway. Growth of subcutaneous xenografts could be inhibited by knockdown of BACH2 or FUS, by overexpressing TSLNC8 or a combination of the three, also leading to a prolonged survival in nude mice. Our results indicate that the BACH2 and FUS/TSLNC8/miR‐10b‐5p/WWC3 axis is responsible for glioma development and could serve as a potential target for the development of new glioma therapies.

ZEB1-Mediated Transcriptional Upregulation of circWWC3 Promotes Breast Cancer Progression through Activating Ras Signaling Pathway

Zinc finger E-box binding homeobox 1 (ZEB1) has been widely recognized as an important driver of tumor growth and metastasis. However, nothing is known about ZEB1-regulated circular (circ)RNAs in cancer. In the current study, we evaluated the function of a novel ZEB1-regulated circRNA derived from the WWC3 gene locus, circWWC3 in breast cancer progression. We found that ZEB1 upregulated circWWC3 expression but not the linear WWC3 mRNA expression. circWWC3 is highly expressed in breast cancer tissues and is associated with the poor prognosis of breast cancer patients. Silencing of circWWC3 significantly suppresses the proliferation, migration, and invasion of breast cancer cells. Mechanically, circWWC3 upregulates multiple oncogenes' expression of the Ras signaling pathway through acting as the sponge of microRNA (miR)-26b-3p and miR-660-3p. Moreover, short hairpin (sh)RNA-mediated knockdown of circWWC3 partially antagonized ZEB1-mediated breast cancer growth and metastasis in vivo. Our findings reveal that ZEB1-mediated upregulation of circWWC3 promotes breast cancer progression through activating Ras signaling pathway, which provides a potential therapeutic target and prognostic biomarker for breast cancer.

WW and C2 domain-containing protein-3 promoted EBSS-induced apoptosis through inhibiting autophagy in non-small cell lung cancer cells

Background

WW and C2 domain-containing protein-3 (WWC3) was identified in our previous studies as a tumor suppressor gene, which inhibits the proliferation and invasiveness of lung cancer cells. However, the relationship between WWC3 and autophagy and apoptosis in lung cancer cells is unclear. In this study, we aimed to investigate the potential role of WWC3 in starvation-induced autophagy and apoptosis in non-small cell lung carcinoma (NSCLC) cells.

Methods

The immunoblotting assay and quantitative real-time polymerase chain reaction (RT-qPCR) were used for observing the change of WWC3 protein and mRNA level under starvation condition. The immunoblotting assay and immunofluorescence assay were performed to detect the impact of WWC3 expression on autophagy process induced by Earle's balanced salt solution (EBSS) in lung cancer cells; APC/propidium iodide (PI) apoptosis assay, caspase-3/7 activity assay and MTT assay were used for the apoptosis and proliferation detection of lung cancer cells.

Results

After starvation had been induced with EBSS, WWC3 expression was significantly decreased in the NSCLC cells. Ectopic WWC3 expression weakened the autophagy process in a Beclin1-independent manner and promoted non-small cell lung cancer cell apoptosis via EBSS starvation. Moreover, the inhibition of WWC3 gene knockout was weakened by 3-methyladenine (3-MA), an autophagy inhibitor.

Conclusions

These results indicate that WWC3 promotes apoptosis and death of starved lung cancer cells, at least partly through autophagy.

SOX9 promotes epithelial-mesenchymal transition via the Hippo-YAP signaling pathway in gastric carcinoma cells

SRY-box 9 (SOX9) is overexpressed in a number of human tumors, including gastric cancer (GC). However, the function of SOX9 in the development of GC remains unknown. In the present study, SOX9 activated the Hippo-yes-associated protein (YAP) signaling pathway to enhance the epithelial-mesenchymal transition in GC cell lines. The results suggested that SOX9 knockdown inhibited invasion, proliferation and migration of GC cells. Furthermore, SOX9 silencing upregulated the expression of E-cadherin, an epithelial marker, and downregulated the expression of mesenchymal markers, including snail family transcriptional repressor 1, vimentin and N-cadherin. SOX9 overexpression increased the expression of the aforementioned markers. SOX9 significantly affected YAP phosphorylation and total YAP protein levels, suggesting that SOX9 is involved in the Hippo-YAP signaling pathway. The current study revealed that SOX9 may be involved in the pathogenesis of GC, and further elucidation of the pathways involved may support the development of novel therapeutic options for the treatment of GC.

Gene pair based prognostic signature for colorectal colon cancer

BACKGROUND

The identification of high-risk colorectal cancer (CRC) patient is key to individualized treatment after surgery and reliable prognostic biomarkers are needed identifying high-risk CRC patients.

METHODS

We developed a gene pair based prognostic signature that could can the prognosis risk in patients with CRC. This study retrospectively analyzed 4 public CRC datasets, and 1123 patients with CRC were divided into a training cohort (n = 300) and 3 independent validation cohorts (n = 507, 226, and 90 patients).

RESULTS

A signature of 9 prognosis-related gene pairs (PRGPs) consisting of 17 unique genes was constructed. Then, a PRGP index (PRGPI) was constructed and divided patients into high- and low-risk groups according to the signature score. Patients in the high-risk group showed a poorer relapse-free survival than the low-risk group in both the training cohort [hazard ratio (HR) range, 4.6, 95% confidence interval (95% CI), 2.55-8.32; P < .0001] and meta-validation set (hazard ratio range, 4.09, 95% CI, 1.99-8.39; P < .0001). The PRGPI signature achieved a higher accuracy [mean concordance index (C-index): 0.6∼0.74] than a commercialized molecular signature (mean C-index, 0.48∼0.56) for estimation of relapse-free survival in comparable validation sets.

CONCLUSION

The gene pair based prognostic signature is a promising biomarker for estimating relapse-free survival of CRC.

Loss of KIBRA function activates EGFR signaling by inducing AREG

The Hippo signaling pathway is a central regulator of organ size, tissue homeostasis, and tumorigenesis. KIBRA is a member of the WW domain-containing protein family and has recently been reported to be an upstream protein in the Hippo signaling pathway. However, the clinical significance of KIBRA deregulation and the underlying mechanisms by which KIBRA regulates breast cancer (BC) initiation and progression remain poorly understood. Here, we report that KIBRA knockdown in mammary epithelial cells induced epithelial-to-mesenchymal transition (EMT) and increased cell migration and tumorigenic potential. Mechanistically, we observed that inhibiting KIBRA induced growth factor-independent cell proliferation in 2D and 3D culture due to the secretion of amphiregulin (AREG), an epidermal growth factor receptor (EGFR) ligand. Also, we show that AREG activation in KIBRA-knockdown cells depended on the transcriptional coactivator YAP1. Significantly, decreased expression of KIBRA is correlated with recurrence and reduced BC patient survival. In summary, this study elucidates the molecular events that underpin the role of KIBRA in BC. As a result, our work provides biological insight into the role of KIBRA as a critical regulator of YAP1-mediated oncogenic growth, and may have clinical potential for facilitating patient stratification and identifying novel therapeutic approaches for BC patients.

WWC3 inhibits epithelial-mesenchymal transition of lung cancer by activating Hippo-YAP signaling

Background

Though we recently reported that the WWC3 inhibits the invasiveness and metastasis of lung cancer by activating the Hippo pathway, the impact and underlying mechanisms of this process still remain unclear.

Methods

To identify the role of WWC3 in epithelial-mesenchymal transition of lung cancer, we performed immunohistochemistry to detect the expression levels of WWC3 and EMT-related biomarker, and analyzed their correlations in a cohort of 127 patients with NSCLC. Wound healing assay and cell invasion assay were applied to explore cell invasive ability change after WWC3 knockdown. qRT-PCR and immunoblotting were performed to assess mRNA and protein levels of EMT-related biomarkers and the main molecules changes of Hippo signaling caused by WWC3. Immunoprecipition was to examine WWC3 and LATS1 interaction.

Results

WWC3 knockdown drives a pronounced shift from the epithelial to the mesenchymal phenotype in lung cancer cells. In addition, WWC3 ectopic expression in lung cancer cells attenuates mesenchymal markers and increases the epithelial markers expressions; however, WWC3-ΔWW plasmid abrogated these effects. WWC3 silencing by shRNA exerts the opposite effect. Furthermore, WWC3 levels were inversely correlated with the levels of EMT inducers (Snail and Slug) in lung cancer cells and specimens. Immunoblotting revealed that WWC3 wild-type upregulates large tumor suppressor (LATS1) and yes-associated protein (YAP) phosphorylation through its WW domain, hence activating Hippo pathway. Knockdown of YAP and LATS1, as well as the as the Verteporfin (VP) usage, could reverse this effect caused by WWC3 silencing.

Conclusion

These findings suggest that WWC3 works as a tumor suppressor to inhibit EMT process and confer its candidacy as a potential therapeutic target in lung cancer.

WWC3 Inhibits Glioma Cell Proliferation Through Suppressing the Wnt/β-Catenin Signaling Pathway

The scaffolding protein WW and C2 domain-containing protein 3 (WWC3) belonging to the WWC protein family plays important roles in regulating cell proliferation, cell migration, and synaptic signaling. The critical role of WWC3 in tumorigenesis has emerged recently; however, the expression and function of WWC3 in glioma remain largely unknown. Here, we found that WWC3 was significantly downregulated in glioma tissues and cell lines. Overexpression of WWC3 inhibited the glioma cell proliferation, migration, and invasion. Depletion of WWC3 promoted the proliferation of glioma cells. Mechanistically, we found that overexpression of WWC3 suppressed the activity of β-catenin, the signaling that tightly associates with cell proliferation and growth. Depletion of WWC3 enhanced the activity of β-catenin/Wnt signaling. Further investigation demonstrated that WWC3 interacted with T cell factor 4 (TCF4), an identified associated binding partner of β-catenin. The interaction between WWC3 and TCF4 might inhibit the transcriptional activation of β-catenin. Our results provide novel insights into the aberrant expression and molecular mechanism of WWC3 in glioma, which indicated WWC3 as a potential target for clinical intervention in glioma.

Multicenter phase II study of apatinib treatment for metastatic gastric cancer after failure of second-line chemotherapy

Apatinib is a tyrosine kinase inhibitor and vascular endothelial growth factor receptor 2 (VEGFR-2) targeted drug. A phase I clinical trial showed that this agent has antitumor activity in Chinese patients with metastatic gastric cancer (mGC). The aim of this study was to investigate the safety and efficacy of apatinib treatment in patients with mGC.

This was an open-label, multicenter, single-arm study involving four institutions in China. We enrolled 42 patients from March 2015 to October 2015 who experienced tumor progression after second-line chemotherapy and had no other treatment options that clearly conferred a survival benefit. Oral apatinib (850 mg daily) was administered within 30 min of eating breakfast, lunch, or dinner on days 1 through 28 of each 4-week cycle.

The median progression-free survival (PFS) time and median overall survival (OS) time were 4.0 months (95% CI, 2.85-5.15) and 4.50 months (95% CI, 4.03-4.97), respectively. The disease control rate (DCR) and objective response rate (ORR) were, respectively, 78.57% and 9.52% after 2 cycles and 57.14% and 19.05% after 4 cycles. The main adverse events (AEs) were secondary hypertension, elevated aminotransferase, and hand-foot syndrome, with incidences of 35.71%, 45.24%, and 40.48%, respectively. The most common grade 3 to 4 AEs were secondary hypertension and elevated aminotransferase, with incidences of 7.14% each.

Apatinib is effective and safe in heavily pretreated patients with mGC who fail to respond to two or more prior chemotherapy regimens. Toxicities were tolerable or could be clinically managed.