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Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by various disabling symptoms including exercise intolerance and is diagnosed in the absence of a specific cause, making its clinical management challenging. A better understanding of the molecular mechanism underlying this apparent bioenergetic deficiency state may reveal insights for developing targeted treatment strategies. We report that overexpression of Wiskott-Aldrich Syndrome Protein Family Member 3 (WASF3), here identified in a 38-y-old woman suffering from long-standing fatigue and exercise intolerance, can disrupt mitochondrial respiratory supercomplex formation and is associated with endoplasmic reticulum (ER) stress. Increased expression of WASF3 in transgenic mice markedly decreased their treadmill running capacity with concomitantly impaired respiratory supercomplex assembly and reduced complex IV levels in skeletal muscle mitochondria. WASF3 induction by ER stress using endotoxin, well known to be associated with fatigue in humans, also decreased skeletal muscle complex IV levels in mice, while decreasing WASF3 levels by pharmacologic inhibition of ER stress improved mitochondrial function in the cells of the patient with chronic fatigue. Expanding on our findings, skeletal muscle biopsy samples obtained from a cohort of patients with ME/CFS showed increased WASF3 protein levels and aberrant ER stress activation. In addition to revealing a potential mechanism for the bioenergetic deficiency in ME/CFS, our study may also provide insights into other disorders associated with fatigue such as rheumatic diseases and long COVID. [ABSTRACT FROM AUTHOR]

Abstract Background Metastasis is most often the root cause of cancer-related death. Human short stature homeobox 2 (SHOX2), a homeodomain transcription factor, is a novel inducer of epithelial-to-mesenchymal transition in breast cancer cells, though its exact role and underlying mechanisms in metastasis are not well understood. Methods TCGA analysis was performed to identify the clinical relevance of SHOX2 in breast cancer. Gene depletion was achieved by short hairpin RNA and small interfering RNA. Molecular regulations and alterations were assessed by Western blotting, immunoprecipitation, immunohistochemistry, qRT-PCR, chromatin immunoprecipitation coupled with qPCR (ChIP-qPCR), and ChIP/re-ChIP. The impact of SHOX2 signaling on tumor growth and metastasis was evaluated in orthotopic breast tumor mice. Results The expression level of SHOX2 is strongly associated with poor distant metastasis-free survival in breast cancer patients and inactivation of SHOX2 suppresses breast tumor growth and metastasis in mice. In breast cancer cells, SHOX2 directly activates Wiskott-Aldridge syndrome protein family member 3 (WASF3), a metastasis-promoting gene, at the transcriptional level, leading to a significant increase in metastatic potential. Mechanistically, SHOX2 activates signal transducer and activator of transcription 3 (STAT3) and recruits it to the WASF3 promoter, where STAT3 cooperates with SHOX2 to form a functional immunocomplex to promote WASF3 transcriptional activity in breast cancer cells. WASF3 knockdown abrogates SHOX2-induced metastasis, but not SHOX2-dependent tumorigenesis. Conclusions These findings provide a critical link between the SHOX2-STAT3-WASF3 signaling axis and metastasis and suggest that the targeting of this signaling node may represent a valuable alternative strategy for combating breast cancer metastasis.

Background: Metastasis is most often the root cause of cancer-related death. Human short stature homeobox 2 (SHOX2), a homeodomain transcription factor, is a novel inducer of epithelial-to-mesenchymal transition in breast cancer cells, though its exact role and underlying mechanisms in metastasis are not well understood. Methods: TCGA analysis was performed to identify the clinical relevance of SHOX2 in breast cancer. Gene depletion was achieved by short hairpin RNA and small interfering RNA. Molecular regulations and alterations were assessed by Western blotting, immunoprecipitation, immunohistochemistry, qRT-PCR, chromatin immunoprecipitation coupled with qPCR (ChIP-qPCR), and ChIP/re-ChIP. The impact of SHOX2 signaling on tumor growth and metastasis was evaluated in orthotopic breast tumor mice. Results: The expression level of SHOX2 is strongly associated with poor distant metastasis-free survival in breast cancer patients and inactivation of SHOX2 suppresses breast tumor growth and metastasis in mice. In breast cancer cells, SHOX2 directly activates Wiskott-Aldridge syndrome protein family member 3 (WASF3), a metastasis-promoting gene, at the transcriptional level, leading to a significant increase in metastatic potential. Mechanistically, SHOX2 activates signal transducer and activator of transcription 3 (STAT3) and recruits it to the WASF3 promoter, where STAT3 cooperates with SHOX2 to form a functional immunocomplex to promote WASF3 transcriptional activity in breast cancer cells. WASF3 knockdown abrogates SHOX2-induced metastasis, but not SHOX2-dependent tumorigenesis. Conclusions: These findings provide a critical link between the SHOX2-STAT3-WASF3 signaling axis and metastasis and suggest that the targeting of this signaling node may represent a valuable alternative strategy for combating breast cancer metastasis. [ABSTRACT FROM AUTHOR]

Cancer cells with cancer stem cell (CSC) properties initiate both primary tumor formation and metastases at distant sites. Acquisition of CSC properties is highly associated with epigenetic alterations, including those mediated by microRNAs (miRNAs). We have previously established the breast cancer patient‐derived tumor xenograft (PDX) mouse model in which CSC marker CD44+ cancer cells formed spontaneous microscopic metastases in the liver. In this PDX mouse, we found that the expression levels of 3 miRNAs (miR‐25, miR‐93, and miR‐106b) in the miR‐106b‐25 cluster were much lower in the CD44+ human cancer cells metastasized to the liver than those at the primary site. Constitutive overexpression of miR‐93 suppressed invasive ability and 3D‐organoid formation capacity of breast cancer cells in vitro and significantly suppressed their metastatic ability to the liver in vivo. Wiskott‐Aldrich syndrome protein family member 3 (WASF3), a regulator of both cytoskeleton remodeling and CSC properties, was identified as a functional target of miR‐93: overexpression of miR‐93 reduced the protein level of WASF3 in breast cancer cells and WASF3 rescued the miR‐93‐mediated suppression of breast cancer cell invasion. These findings suggest that miR‐93 functions as a metastasis suppressor by suppressing both invasion ability and CSC properties in breast cancers. [ABSTRACT FROM AUTHOR]

Aim:WASF3 has been shown to be required for invasion and metastasis in different cancers, this study is to explore the prognostic value of WASF3 in gastric cancer. Materials & methods: The coexpression of WASF3 and E-cadherin in gastric cancer patients and cells were evaluated. Results:WASF3 was overexpressed and the expression of E-cadherin was decreased in gastric cancer tissues compared with normal tissues (p < 0.001). WASF3 expression is associated with decreased expression of E-cadherin (p = 0.002). Patients with WASF3-positive expression had a poorer prognosis. The multivariate analysis showed that WASF3 expression is an independent prognostic factor related to overall survival (p = 0.027). Conclusion: Our analysis demonstrates that WASF3 expression correlates with poor outcomes and is a potential prognostic factor in gastric cancer patients. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) play an important role in carcinogenesis. miR-218 is one of the most known miRNAs and has been demonstrated to inhibit progression in gastric cancer. However, the un1derlying molecular mechanism is not established. In this study, qRT-PCR and Western blot indicated that miR-218 was downregulated in gastric cancer cell lines SGC7901 and BGC823 compared to that in normal gastric epithelial cell line GES-1. MTT and wound scratch assays suggested that overexpression of miR-218 markedly suppressed cell proliferation, migration, and EMT of gastric cancer cells. Furthermore, we proved that WASF3 was a direct target of miR-218 by luciferase reporter assay, and restoration of WASF3 expression impairs miR-218-induced inhibition of proliferation, migration, and EMT in gastric cancer cells SGC7901. In summary, our results demonstrated that miR-218 functions as one of the tumor-suppressive miRNAs and inhibits gastric cancer tumorigenesis by targeting WASF3. miR-218 may serve as a potential therapeutic target for the treatment of gastric cancer. [ABSTRACT FROM AUTHOR]

JAK-STAT3 signaling, while regulating many aspects of cancer development and progression, promotes invasion and metastasis through activation of key metastasis promoting genes such as WASF3. STAT3 promotes wASF3 expression and JAK2 independently activates it, which is required for invasion. JAK-STAT3 signaling is dependent on WASF3 function, since its inactivation in cells expressing JAK-STAT3 suppresses invasion. WASF3 overexpression leads to activation of NFκB and ZeB1 which also promote invasion through regulation of target genes involved in metastasis. NFκB frequently cooperates with STAT3 to upregulate metastasis promoting genes such as matrix metalloproteinases and cytokines, as well as to suppress microRNAs which can suppresses invasion. This better understanding of the complex role played by JAK-STAT3 in the regulation of cell movement, invasion, and metastasis provides opportunities to suppress this lethal aspect of cancer progression by not only targeting the JAK and STAT3 proteins directly, but also some of the downstream effectors of JAK-STAT3 signaling. [ABSTRACT FROM AUTHOR]

Background: The WASF3 protein is involved in cell movement and invasion, and to investigate its role in prostate cancer progression we studied the phenotypic effects of knockdown in primary tumors and cell lines.Methods: ShRNA was used to knockdown WASF3 function in prostate cell lines. Cell motility (scratch wound assay), anchorage independent growth and in vivo tumorigenicity and metastasis were then compared between knockdown and wild-type cells.Results: Increased levels of expression were seen in high-grade human prostate cancer and in the PC3 and DU145 cell lines. Inactivation of WASF3 using shRNAs reduced cell motility and invasion in these cells and reduced anchorage independent growth in vitro. The loss of motility was accompanied by an associated increase in stress fiber formation and focal adhesions. When injected subcutaneously into severe combined immunodeficiency (SCID) mice, tumor formation was significantly reduced for PC3 and DU145 cells with WASF3 knockdown and in vivo metastasis assays using tail vain injection showed a significant reduction for PC3 and DU145 cells. The loss of the invasion phenotype was accompanied by down-regulation of matrix metalloproteinase 9.Conclusions: Overall, these observations demonstrate a critical role for WASF3 in the progression of prostate cancer and identify a potential target to control tumorigenicity and metastasis. [ABSTRACT FROM AUTHOR]

Increasing evidence indicates that cancer metastasis is regulated by specific genetic pathways independent of those controlling tumorigenesis and cancer growth. WASF3, a Wiskott–Aldrich syndrome protein family member, appears to play a major role not only in the regulation of actin cytoskeleton dynamics but also in cancer cell invasion/metastasis. Recent studies have highlighted that WASF3 is a master regulator and acts as a pivotal scaffolding protein, bringing the various components of metastatic signaling complexes together both spatially and temporally. Herein, targeting WASF3 at the levels of transcription, protein stability, and phosphorylation holds great promise for metastasis suppression, regardless of the diverse genetic backgrounds associated with tumor development. This review focuses on the critical and distinct contributions of WASF3 in the regulation of signal pathways promoting cancer cell invasion and metastasis. [ABSTRACT FROM AUTHOR]

Aim: WASF3 has been shown to be required for invasion and metastasis in different cancers, this study is to explore the prognostic value of WASF3 in gastric cancer.  Materials & methods: The coexpression of WASF3 and E-cadherin in gastric cancer patients and cells were evaluated. Results: WASF3 was overexpressed and the expression of E-cadherin (p = 0.002). Patients with WASF3-positive expression had a poorer prognosis. The multivariate analysis showed that WASF3 expression is an independent prognostic factor related to overall survival (p = 0.027). WASF3 expression is associated with decreased expression of E-cadherin (p = 0.002). Patients with WASF3-positive expression had a poorer prognosis. The multivariate analysis showed that WASF3 expression is an independent prognostic factor related to overall survival (p = 0.027). Conclusion:  Our analysis demonstrates that WASF3 expression correlates with poor outcomes and is a potential prognostic factor in gastric cancer patients.

The WASF3 gene facilitates the metastatic phenotype, and its inactivation leads to suppression of invasion and metastasis regardless of the genetic background of the cancer cell. This reliance on WASF3 to facilitate metastasis suggests that targeting its function could serve as an effective strategy to suppress metastasis. WASF3 stability and function are regulated by the WASF Regulatory Complex (WRC) of proteins, particularly CYFIP1 and NCKAP1. Knockdown of these proteins in vitro leads to disruption of the WRC and suppression of invasion. We have used mouse xenograft models of breast cancer metastasis to assess whether targeting the WRC complex suppresses metastasis in vivo. Stapled peptides targeting the WASF3-CYFIP1 interface (WAHM1) and the CYFIP1-NCKAP1 interface (WANT3) suppress the development of lung and liver metastases. Targeting these critical protein-protein interactions, therefore, could potentially be developed into a therapeutic strategy to control cancer cell invasion and metastasis., Competing Interests: DECLARATION OF CONFLICTING INTERESTS: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.