Role of Telomeres and Telomerase in Parkinson's Disease-A New Theranostics?

Parkinson's disease (PD) is a complex condition that is significantly influenced by oxidative stress and inflammation. It is also suggested that telomere shortening (TS) is regulated by oxidative stress which leads to various diseases including age-related neurodegenerative diseases like PD. Thus, it is anticipated that PD would result in TS of peripheral blood mononuclear cells (PBMCs). Telomeres protect the ends of eukaryotic chromosomes preserving them against fusion and destruction. The TS is a normal process because DNA polymerase is unable to replicate the linear ends of the DNA due to end replication complications and telomerase activity in various cell types counteracts this process. PD is usually observed in the aged population and progresses over time therefore, disparities among telomere length in PBMCs of PD patients are recorded and it is still a question whether it has any useful role. Here, the likelihood of telomere attrition in PD and its implications concerning microglia activation, ageing, oxidative stress, and the significance of telomerase activators are addressed. Also, the possibility of telomeres and telomerase as a diagnostic and therapeutic biomarker in PD is discussed.

Improved Wound Healing and Skin Regeneration Ability of 3,2'-Dihydroxyflavone-Treated Mesenchymal Stem Cell-Derived Extracellular Vesicles.

Flavonoids enhance the self-renewal and differentiation potential of mesenchymal stem cells (MSCs) and have therapeutic activities, including regenerative, anti-oxidative, and anti-inflammatory effects. Recent studies have revealed that MSC-derived extracellular vesicles (MSC-EVs) have therapeutic effects on tissue regeneration and inflammation. To facilitate further research on the therapeutic potential of MSC-EVs derived from flavonoid-treated MSCs, we surveyed the production of EVs and their therapeutic applications in wound regeneration. MSCs treated with flavonoids enhanced EV production twofold compared with naïve MSCs. EVs produced by MSCs treated with flavonoids (Fla-EVs) displayed significant anti-inflammatory and wound-healing effects in vitro. The wound-healing capacity of EVs was mediated by the upregulation of mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling. Interestingly, the protein level of p-ERK under inhibition of MEK signals was maintained in Fla-EV-treated fibroblasts, suggesting that Fla-EVs have a higher therapeutic potential than naïve MSC-EVs (Cont-EVs) in wound healing. Moreover, the in vivo wound closure effect of the Fla-EVs showed significant improvement compared with that of the flavonoid-only treatment group and the Cont-EVs. This study provides a strategy for the efficient production of EVs with superior therapeutic potential using flavonoids.

Ductal delivery of extracellular vesicles promote the recovery from salivary gland inflammation.

Salivary gland dysfunction worsens the quality of life, but treatment for restoration of salivary gland function is limited. Although previous reports have demonstrated the therapeutic potentials of extracellular vesicles (EVs) in different preclinical models, the role of EVs in salivary glands remains elusive. Furthermore, little is known about the roles of salivary gland-derived EVs in tissue repair or regeneration compared to other EVs. In this study, EVs secreted from salivary gland-derived mesenchymal stem cells (sgMSCs) were comparatively analyzed with those from Wharton's jelly-derived MSC (wjMSCs). sgMSCs secreted more significant amounts of EVs than wjMSCs, and salivary gland epithelial cells showed a more efficient uptake of sgMSC-EVs than wjMSC-EVs. The possibility of immune regulation was tested via macrophage polarization and LPS-induced epithelial inflammation, resulting in an M1-to-M2 shift and reversal of acinar-to-ductal metaplasia by sgMSC-EV. Furthermore, the roles of sgMSC-EV-mediated immune regulation and tissue repair were clarified in vivo via retroductal delivery of sgMSC-EVs in a mouse model of obstructive sialadenitis. Collectively, our data demonstrate the superior role of sgMSC-EVs in the recovery from salivary gland inflammation and injury and suggest EVs as therapeutic tools for salivary gland dysfunction.

TMBIM6-mediated miR-181a expression regulates breast cancer cell migration and invasion via the MAPK/ERK signaling pathway.

Transmembrane Bax Inhibitor Motif-containing 6 (TMBIM6) has been reported to regulate cell death pathways and is overexpressed in several types of cancers. In this study, we investigated whether high expression of TMBIM6 in breast cancer was significantly associated with cancer invasiveness. Knockdown of TMBIM6 reduced proliferation and migration of invasive breast cancer cells through downregulation of the MAPK/ERK signaling pathway. Moreover, we suggested that expression of miR-181a was significantly suppressed upon TMBIM6 knockdown. In contrast, overexpression of TMBIM6 significantly increased cell invasion and migration through up-regulation of mesenchymal markers and matrix metalloproteinase-9 (MMP-9) and enhanced activation of the MAPK/ERK signaling pathway. We also observed that up-regulation of TMBIM6 significantly increased the expression of miR-181a by TMBIM6-mediated pathway. TMBIM6 and miR-181a-mediated ERK activation induced the expression of Snail-1 and Snail-2 in FOSL-1/C-JUN-dependent manner. Overall, our data demonstrated that TMBIM6-induced miR-181a up-regulation plays an important role in the efficient modulation of migration and invasion of breast cancer cells.

The Orphan GPR50 Receptor Regulates the Aggressiveness of Breast Cancer Stem-like Cells via Targeting the NF-kB Signaling Pathway.

The expression of GPR50 in CSLC and several breast cancer cell lines was assessed by RT-PCR and online platform (UALCAN, GEPIA, and R2 gene analysis). The role of GPR50 in driving CSLC, sphere formation, cell proliferation, and migration was performed using shGPR50 gene knockdown, and the role of GPR50-regulated signaling pathways was examined by Western blotting and Luciferase Assay. Herein, we confirmed that the expression of G protein-coupled receptor 50 (GPR50) in cancer stem-like cells (CSLC) is higher than that in other cancer cells. We examined that the knockdown of GPR50 in CSLC led to decreased cancer properties, such as sphere formation, cell proliferation, migration, and stemness. GPR50 silencing downregulates NF-kB signaling, which is involved in sphere formation and aggressiveness of CSLC. In addition, we demonstrated that GPR50 also regulates ADAM-17 activity by activating NOTCH signaling pathways through the AKT/SP1 axis in CSLC. Overall, we demonstrated a novel GPR50-mediated regulation of the NF-κB-Notch signaling pathway, which can provide insights into CSLC progression and prognosis, and NF-κB-NOTCH-based CSLC treatment strategies.

Rapid production method with increased yield of high-purity extracellular vesicles obtained using extended mitochondrial targeting domain peptide.

Extracellular vesicles (EVs) are nano-sized membranous structures involved in intercellular communication and various physiological and pathological processes. Here, we present a novel method for rapid (within 15 min), large-scale production of high-purity EVs using eMTDΔ4, a peptide derived from Noxa. The treatment of mesenchymal stem cells derived from human Wharton's jelly after trypsinization and subsequent eMTDΔ4 stimulation in a chemically defined sucrose buffer with orbital shaking led to a substantial increase (approximately 30-fold) in EV production with markedly high purity (approximately 45-fold). These EVs (TS-eEVs) showed higher regenerative and immunomodulatory potential than natural EVs obtained from the culture media after 48 h. The calcium chelator BAPTA-AM and calpain inhibitor ALLM, but not the natural EV biogenesis inhibitor GW4869, blocked the TS-eEV production induced by eMTDΔ4, indicating that the eMTDΔ4-mediated regulation of intracellular calcium levels and calpain activity are closely associated with the rapid, mass production of TS-eEVs. The present study may lead to considerable advances in EV-based drug development and production of stem cell-derived EVs for cell therapy.

TTYH3 Modulates Bladder Cancer Proliferation and Metastasis via FGFR1/H-Ras/A-Raf/MEK/ERK Pathway.

Tweety family member 3 (TTYH3) is a calcium-activated chloride channel with a non-pore-forming structure that controls cell volume and signal transduction. We investigated the role of TTYH3 as a cancer-promoting factor in bladder cancer. The mRNA expression of TTYH3 in bladder cancer patients was investigated using various bioinformatics databases. The results demonstrated that the increasingly greater expression of TTYH3 increasingly worsened the prognosis of patients with bladder cancer. TTYH3 knockdown bladder cancer cell lines were constructed by their various cancer properties measured. TTYH3 knockdown significantly reduced cell proliferation and sphere formation. Cell migration and invasion were also significantly reduced in knockdown bladder cancer cells, compared to normal bladder cancer cells. The knockdown of TTYH3 led to the downregulation of H-Ras/A-Raf/MEK/ERK signaling by inhibiting fibroblast growth factor receptor 1 (FGFR1) phosphorylation. This signaling pathway also attenuated the expression of c-Jun and c-Fos. The findings implicate TTYH3 as a potential factor regulating the properties of bladder cancer and as a therapeutic target.

Modulation of Osteogenic Differentiation of Adipose-Derived Stromal Cells by Co-Treatment with 3, 4'-Dihydroxyflavone, U0126, and N-Acetyl Cysteine.

Background and Objectives: Flavonoids form the largest group of plant phenols and have various biological and pharmacological activities. In this study, we investigated the effect of a flavonoid, 3, 4'-dihydroxyflavone (3, 4'-DHF) on osteogenic differentiation of equine adipose-derived stromal cells (eADSCs). Methods and Results: Treatment of 3, 4'-DHF led to increased osteogenic differentiation of eADSCs by increasing phosphorylation of ERK and modulating Reactive Oxygen Species (ROS) generation. Although PD98059, an ERK inhibitor, suppressed osteogenic differentiation, another ERK inhibitor, U0126, apparently increased osteogenic differentiation of the 3, 4'-DHF-treated eADSCs, which may indicate that the effect of U0126 on bone morphogenetic protein signaling is involved in the regulation of 3, 4'-DHF in osteogenic differentiation of eADSCs. We revealed that 3, 4'-DHF could induce osteogenic differentiation of eADSCs by suppressing ROS generation and co-treatment of 3, 4'-DHF, U0126, and/or N-acetyl cysteine (NAC) resulted in the additive enhancement of osteogenic differentiation of eADSCs. Conclusions: Our results showed that co-treatment of 3, 4'-DHF, U0126, and/or NAC cumulatively regulated osteogenesis in eADSCs, suggesting that 3, 4'-DHF, a flavonoid, can provide a novel approach to the treatment of osteoporosis and can provide potential therapeutic applications in therapeutics and regenerative medicine for human and companion animals.

Superior therapeutic activity of TGF-ß-induced extracellular vesicles against interstitial cystitis.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic disease characterized by incapacitating pelvic pain. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are considered key mediators of the paracrine action of MSCs and show better biological activities than the parent MSCs, especially in the bladder tissue, which may be unfavorable for MSC survival. Here, we produced MSC-EVs using advanced three-dimensional (a3D) culture with exogenous transforming growth factor-ß3 (TGF-ß3) (T-a3D-EVs). Treatment with T-a3D-EVs led to significantly enhanced wound healing and anti-inflammatory capacities. Moreover, submucosal layer injection of T-a3D-EVs in chronic IC/BPS animal model resulted in restoration of bladder function, superior anti-inflammatory activity, and recovery of damaged urothelium compared to MSCs. Interestingly, we detected increased TGF-ß1 level in T-a3D-EVs, which might be involved in the anti-inflammatory activity of these EVs. Taken together, we demonstrate the excellent immune-modulatory and regenerative abilities of T-a3D-EVs as observed by recovery from urothelial denudation and dysfunction, which could be a promising therapeutic strategy for IC/BPS.

New therapeutic approach with extracellular vesicles from stem cells for interstitial cystitis/bladder pain syndrome.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating chronic disorder characterized by suprapubic pain and urinary symptoms such as urgency, nocturia, and frequency. The prevalence of IC/BPS is increasing as diagnostic criteria become more comprehensive. Conventional pharmacotherapy against IC/BPS has shown suboptimal effects, and consequently, patients with end-stage IC/BPS are subjected to surgery. The novel treatment strategies should have two main functions, anti-inflammatory action and the regeneration of glycosaminoglycan and urothelium layers. Stem cell therapy has been shown to have dual functions. Mesenchymal stem cells (MSCs) are a promising therapeutic option for IC/BPS, but they come with several shortcomings, such as immune activation and tumorigenicity. MSC-derived extracellular vesicles (MSC-EVs) hold numerous therapeutic cargos and are thus a viable cell-free therapeutic option. In this review, we provide a brief overview of IC/BPS pathophysiology and limitations of the MSC-based therapies. Then we provide a detailed explanation and discussion of therapeutic applications of EVs in IC/BPS as well as the possible mechanisms. We believe our review will give an insight into the strengths and drawbacks of EV-mediated IC/BPS therapy and will provide a basis for further development. [BMB Reports 2022; 55(5): 205-212].

Effects of carrier solutions on the viability and efficacy of canine adipose-derived mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cells (MSCs) have favorable characteristics that render them a potent therapeutic tool. We tested the characteristics of MSCs after temporal storage in various carrier solutions, such as 0.9% saline (saline), 5% dextrose solution (DS), heparin in saline, and Hartmann's solution, all of which are approved by the U.S. Food and Drug Administration (FDA). Phosphate-buffered saline, which does not have FDA approval, was also used as a carrier solution. We aimed to examine the effects of these solutions on the viability and characteristics of MSCs to evaluate their suitability and efficacy for the storage of canine adipose-derived MSCs (cADMSCs). RESULTS: We stored the cADMSCs in the test carrier solutions in a time-dependent manner (1, 6, and 12 h) at 4 °C, and analyzed cell confluency, viability, proliferation, self-renewability, and chondrogenic differentiation. Cell confluency was significantly higher in 5% DS and lower in phosphate-buffered saline at 12 h compared to other solutions. cADMSCs stored in saline for 12 h showed the highest viability rate. However, at 12 h, the proliferation rate of cADMSCs was significantly higher after storage in 5% DS and significantly lower after storage in saline, compared to the other solutions. cADMSCs stored in heparin in saline showed superior chondrogenic capacities at 12 h compared to other carrier solutions. The expression levels of the stemness markers, Nanog and Sox2, as well as those of the MSC surface markers, CD90 and CD105, were also affected over time. CONCLUSION: Our results suggest that MSCs should be stored in saline, 5% DS, heparin in saline, or Hartmann's solution at 4 °C, all of which have FDA approval (preferable storage conditions: less than 6 h and no longer than 12 h), rather than storing them in phosphate-buffered saline to ensure high viability and efficacy.

High Therapeutic and Esthetic Properties of Extracellular Vesicles Produced from the Stem Cells and Their Spheroids Cultured from Ocular Surgery-Derived Waste Orbicularis Oculi Muscle Tissues.

Extracellular vesicles (EVs) are paracrine factors that mediate stem cell therapeutics. We aimed at evaluating the possible therapeutic and esthetic applications of EVs prepared from the waste human facial tissue-derived orbicularis oculi muscle stem cells (OOM-SCs). OOM-SCs were isolated from the ocular tissues (from elders and youngsters) after upper eyelid blepharoplasty or epiblepharon surgeries. EVs were prepared from the OOM-SCs (OOM-SC-EVs) and their three-dimensional spheroids. OOM-SCs showed a spindle-like morphology with trilineage differentiation capacity, positive expression of CD105, CD 90, and CD73, and negative expression of CD45 and CD34, and their stem cell properties were compared with other adult mesenchymal stem cells. OOM-SC-EVs showed a high inhibitory effect on melanin synthesis in B16F10 cells by blocking tyrosinase activity. OOM-SC-EVs treatment led to a significant attenuation of senescence-associated changes, a decrease in reactive oxygen species generation, and an upregulation of antioxidant genes. We demonstrated the regeneration activity of OOM-SC-EVs in in vitro wound healing of normal human dermal fibroblasts and upregulation of anti-wrinkle-related genes and confirmed the therapeutic potential of OOM-SC-EVs in the healing of the in vivo wound model. Our study provides promising therapeutic and esthetic applications of OOM-SC-EVs, which can be obtained from the ocular surgery-derived waste human facial tissues.

Multi-Omics Analysis of SOX4, SOX11, and SOX12 Expression and the Associated Pathways in Human Cancers.

The Sry-related HMG BOX (SOX) gene family encodes transcription factors containing highly conserved high-mobility group domains that bind to the minor groove in DNA. Although some SOX genes are known to be associated with tumorigenesis and cancer progression, their expression and prognostic value have not been systematically studied. We performed multi-omic analysis to investigate the expression of SOX genes in human cancers. Expression and phylogenetic tree analyses of the SOX gene family revealed that the expression of three closely related SOX members, SOX4, SOX11, and SOX12, was increased in multiple cancers. Expression, mutation, and alteration of the three SOX members were evaluated using the Oncomine and cBioPortal databases, and the correlation between these genes and clinical outcomes in various cancers was examined using the Kaplan-Meier, PrognoScan, and R2 database analyses. The genes commonly correlated with the three SOX members were categorized in key pathways related to the cell cycle, mitosis, immune system, and cancer progression in liver cancer and sarcoma. Additionally, functional protein partners with three SOX proteins and their probable signaling pathways were explored using the STRING database. This study suggests the prognostic value of the expression of three SOX genes and their associated pathways in various human cancers.

Immunomodulatory effect of mesenchymal stem cells and mesenchymal stem-cell-derived exosomes for COVID-19 treatment.

The world has witnessed unimaginable damage from the coronavirus disease-19 (COVID-19) pandemic. Because the pandemic is growing rapidly, it is important to consider diverse treatment options to effectively treat people worldwide. Since the immune system is at the hub of the infection, it is essential to regulate the dynamic balance in order to prevent the overexaggerated immune responses that subsequently result in multiorgan damage. The use of stem cells as treatment options has gained tremendous momentum in the past decade. The revolutionary measures in science have brought to the world mesenchymal stem cells (MSCs) and MSC-derived exosomes (MSC-Exo) as therapeutic opportunities for various diseases. The MSCs and MSCExos have immunomodulatory functions; they can be used as therapy to strike a balance in the immune cells of patients with COVID-19. In this review, we discuss the basics of the cytokine storm in COVID-19, MSCs, and MSC-derived exosomes and the potential and stem-cell-based ongoing clinical trials for COVID-19. [BMB Reports 2020; 53(8): 400-412].

COVID-19: an update on diagnostic and therapeutic approaches.

The unexpected pandemic set off by the novel coronavirus 2019 (COVID-19) has caused severe panic among people worldwide. COVID-19 has created havoc, and scientists and physicians are urged to test the efficiency and safety of drugs used to treat this disease. In such a pandemic situation, various steps have been taken by the government to control and prevent the Severe Acute Respiratory Syndrome coronavirus 2 (SARSCoV- 2). This pandemic situation has forced scientists to rework strategies to combat infectious diseases through drugs, treatment, and control measures. COVID-19 treatment requires both limiting viral multiplication and neutralizing tissue damage induced by an inappropriate immune reaction. Currently, various diagnostic kits to test for COVID-19 are available, and repurposing therapeutics for COVID-19 has shown to be clinically effective. As the global demand for diagnostics and therapeutics continues to rise, it is essential to rapidly develop various algorithms to successfully identify and contain the virus. This review discusses the updates on specimens/samples, recent efficient diagnostics, and therapeutic approaches to control the disease and repurposed drugs mainly focusing on chloroquine/hydroxychloroquine and convalescent plasma (CP). More research is required for further understanding of the influence of diagnostics and therapeutic approaches to develop vaccines and drugs for COVID-19. [BMB Reports 2020; 53(4): 191-205].

Improved Isolation and Culture of Urine-Derived Stem Cells (USCs) and Enhanced Production of Immune Cells from the USC-Derived Induced Pluripotent Stem Cells.

The availability of autologous adult stem cells is one of the essential prerequisites for human stem cell therapy. Urine-derived stem cells (USCs) are considered as desirable cell sources for cell therapy because donor-specific USCs are easily and non-invasively obtained from urine. Efficient isolation, expansion, and differentiation methods of USCs are necessary to increase their availability. Here, we developed a method for efficient isolation and expansion of USCs using Matrigel, and the rho-associated protein kinase (ROCK) inhibitor, Y-27632. The prepared USCs showed significantly enhanced migration, colony forming capacity, and differentiation into osteogenic or chondrogenic lineage. The USCs were successfully reprogramed into induced pluripotent stem cells (USC-iPSCs) and further differentiated into kidney organoid and hematopoietic progenitor cells (HPCs). Using flavonoid molecules, the isolation efficiency of USCs and the production of HPCs from the USC-iPSCs was increased. Taken together, we present an improved isolation method of USCs utilizing Matrigel, a ROCK inhibitor and flavonoids, and enhanced differentiation of USC-iPSC to HPC by flavonoids. These novel findings could significantly enhance the use of USCs and USC-iPSCs for stem cell research and further application in regenerative stem cell-based therapies.

Application of Adult and Pluripotent Stem Cells in Interstitial Cystitis/Bladder Pain Syndrome Therapy: Methods and Perspectives.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a multifactorial, chronic disease without definite etiology characterized by bladder-related pelvic pain. IC/BPS is associated with pain that negatively affects the quality of life. There are various therapeutic approaches against IC/BPS. However, no efficient therapeutic agent against IC/BPS has been discovered yet. Urothelium dysfunction is one of the key factors of IC/BPS-related pathogenicity. Stem cells, including adult stem cells (ASCs) and pluripotent stem cells (PSCs), such as embryonic stem cells (ESCs) and induced PSCs (iPSCs), possess the abilities of self-renewal, proliferation, and differentiation into various cell types, including urothelial and other bladder cells. Therefore, stem cells are considered robust candidates for bladder regeneration. This review provides a brief overview of the etiology, pathophysiology, diagnosis, and treatment of IC/BPS as well as a summary of ASCs and PSCs. The potential of ASCs and PSCs in bladder regeneration via differentiation into bladder cells or direct transplantation into the bladder and the possible applications in IC/BPS therapy are described in detail. A better understanding of current studies on stem cells and bladder regeneration will allow further improvement in the approaches of stem cell applications for highly efficient IC/BPS therapy.

The immobilization of fibronectin- and fibroblast growth factor 2-derived peptides on a culture plate supports the attachment and proliferation of human pluripotent stem cells.

Pluripotent stem cells (PSCs) offer a promising tool for regenerative medicine. The clinical application of PSCs inevitably requires a large-scale culture in a highly defined environment. The present study aimed to devise defined coating materials for the efficient adhesion and proliferation of human PSCs (hPSCs). We tested the activity of seven fibronectin-derived peptides and three laminin-derived peptides for the attachment and proliferation of hPSCs through their immobilization on the bottom of culture dishes by creating a fusion protein with the mussel adhesion protein. Among the extracellular matrix (ECM) mimetics tested, one fibronectin-derived peptide, PHSRN-GRGDSP, significantly promoted adhesion, enhanced alkaline phosphatase activity, and increased pluripotency-related gene expression in hPSCs compared to Matrigel. Furthermore, co-immobilization of a particular canofin peptide derived from fibroblast growth factor 2 increased pluripotency marker expression, which may offer the possibility of culture without growth factor supplementation. Our findings afford a novel defined condition for the efficient culture of hPSCs and may be utilized in future clinical applications.

Recent advances in organoid culture for insulin production and diabetes therapy: methods and challenges.

Breakthroughs in stem cell technology have contributed to disease modeling and drug screening via organoid technology. Organoid are defined as three-dimensional cellular aggregations derived from adult tissues or stem cells. They recapitulate the intricate pattern and functionality of the original tissue. Insulin is secreted mainly by the pancreatic ß cells. Large-scale production of insulin-secreting ß cells is crucial for diabetes therapy. Here, we provide a brief overview of organoids and focus on recent advances in protocols for the generation of pancreatic islet organoids from pancreatic tissue or pluripotent stem cells for insulin secretion. The feasibility and limitations of organoid cultures derived from stem cells for insulin production will be described. As the pancreas and gut share the same embryological origin and produce insulin, we will also discuss the possible application of gut organoids for diabetes therapy. Better understanding of the challenges associated with the current protocols for organoid culture facilitates development of scalable organoid cultures for applications in biomedicine. [BMB Reports 2019; 52(5): 295-303].

Hydrodynamic shear stress promotes epithelial-mesenchymal transition by downregulating ERK and GSK3ß activities.

BACKGROUND: Epithelial-mesenchymal transition (EMT) occurs in the tumor microenvironment and presents an important mechanism of tumor cell intravasation, stemness acquisition, and metastasis. During metastasis, tumor cells enter the circulation to gain access to distant tissues, but how this fluid microenvironment influences cancer cell biology is poorly understood. METHODS AND RESULTS: Here, we present both in vivo and in vitro evidence that EMT-like transition also occurs in circulating tumor cells (CTCs) as a result of hydrodynamic shear stress (+SS), which promotes conversion of CD24middle/CD44high/CD133middle/CXCR4low/ALDH1low primary patient epithelial tumor cells into specific high sphere-forming CD24low/CD44low/CD133high/CXCR4high/ALDH1high cancer stem-like cells (CSLCs) or tumor-initiating cells (TICs) with elevated tumor progression and metastasis capacity in vitro and in vivo. We demonstrate that conversion of CSLCs/TICs from epithelial tumor cells via +SS is dependent on reactive oxygen species (ROS)/nitric oxide (NO) generation, and suppression of extracellular signal-related kinase (ERK)/glycogen synthase kinase (GSK)3ß, a mechanism similar to that operating in embryonic stem cells to prevent their differentiation while promoting self-renewal. CONCLUSION: Fluid shear stress experienced during systemic circulation of human breast tumor cells can lead to specific acquisition of mesenchymal stem cell (MSC)-like potential that promotes EMT, mesenchymal-epithelial transition, and metastasis to distant organs. Our data revealed that biomechanical forces appeared to be important microenvironmental factors that not only drive hematopoietic development but also lead to acquisition of CSLCs/TIC potential in cancer metastasis. Our data highlight that +SS is a critical factor that promotes the conversion of CTCs into distinct TICs in blood circulation by endowing plasticity to these cells and by maintaining their self-renewal signaling pathways.