Treatment effects of functional appliances in children with Class II malocclusion with and without morphologic deviations in the upper spine.

INTRODUCTION: This research aimed to compare treatment effects of functional appliances between children with and without morphologic deviations in the upper spine and analyze associations between Atlas dimensions and the short- and long-term treatment effects. METHODS: Sixty-eight prepubertal or pubertal children (35 boys and 33 girls; mean age, 11.47 ± 1.39 years) treated with Class II functional appliances were included. Lateral cephalograms were taken at pretreatment (T1), postfunctional appliance treatment (T2), and after retention at postpuberty (T3). Upper spine morphology and Atlas dimensions were evaluated at T1. T1-T2 and T1-T3 lateral cephalograms were superimposed using a structural method. Changes in the jaws were compared with multiple linear regression analysis between children with and without deviations in the upper spine. Associations between the changes and Atlas dimensions were analyzed by partial correlation. RESULTS: Children with morphologic deviations in the upper spine showed significantly more backward rotation of the mandible (P <0.01) and increased inclination of the jaws (P <0.05, P <0.01) from T1-T2 and significantly smaller condylar growth (P <0.01) from T1-T3 compared with children without the deviations. Atlas height was significantly associated with vertical and rotational changes in the mandible (P <0.01) from T1-T2 and condylar growth (P <0.05) from T1-T2 and T1-T3. CONCLUSIONS: Morphologic deviations in the upper spine and low Atlas height were significantly associated with smaller condylar growth induced by functional appliances in the long term. Upper spine morphology and the Atlas dimension may be valuable in phenotypic differentiation in children with Class II malocclusion for optimal treatment outcome.

Ethnic differences in craniofacial and upper spine morphology between European and Asian children with skeletal Class III malocclusion.

INTRODUCTION: The aims of this study were to analyze differences in craniofacial and upper cervical spine morphology, including posterior cranial fossa and growth prediction signs between European and Asian skeletal Class III children, and to analyze associations between morphologic deviations in the upper cervical spine and craniofacial characteristics. METHODS: A total of 60 skeletal Class III children, 19 Danes and 41 Koreans, were included. Upper spine morphology, Atlas dimensions, and craniofacial morphology, including posterior cranial fossa and growth prediction signs, were assessed on lateral cephalograms. Differences and associations were analyzed by multiple linear and logistic regression analyses adjusted for age and gender. RESULTS: In the craniofacial morphology, the inclination of the maxilla (NSL/NL, P <0.05) and the shape of the posterior cranial fossa (s-d, d-p, p-iop; P <0.01 and P <0.0001, respectively) were significantly different between the 2 groups. There was no significant difference in upper cervical spine morphology and Atlas dimensions between the groups. Fusion was significantly associated with the sagittal jaw relationship (P <0.05), and the total upper spine deviations were significantly associated with some growth prediction signs (P <0.05, P <0.01). Atlas dimensions were significantly associated with the prognathia of the mandible (P <0.05), posterior cranial fossa (P <0.01, P <0.0001), and some growth prediction signs (P <0.05, P <0.01). CONCLUSIONS: Upper spine morphology and Atlas dimensions may provide valuable information for predicting jaw growth and craniofacial morphology in Class III malocclusion.

Flubendazole elicits anti-metastatic effects in triple-negative breast cancer via STAT3 inhibition.

Tumor metastasis remains the cause of 90% of cancer-related deaths. Cancer stem cells (CSC) are thought to be responsible for the aggressive and metastatic nature of triple-negative breast cancers (TNBC), and new therapeutic strategies are being devised to target them. Flubendazole (FLU) is a widely used anthelmintic agent that also exhibits anticancer activity in several cancer types. The aim of this study was to characterize the mechanism of action of FLU on breast cancer stem cell (BCSC)-like properties and metastasis in TNBC. FLU treatment caused a significant induction of apoptosis, accompanied by G2/M phase accumulation, caspase-3/-7 activation and the dysregulation of STAT3 activation in TNBC cells. The latter phenomenon was associated with impairment of cancer stem-like traits, concomitant with a reduction in the CD24low /CD44high , CD24high /CD49fhigh subpopulation, ALDH1 activity and mammosphere formation. The BCSC-enriched populations exhibited enhanced metastasis with higher STAT3 activation, while FLU administration inhibited tumor growth, angiogenesis and lung and liver metastasis, coinciding with decreased MMP-2 and MMP-9 levels in circulating blood. FLU kills not only rapid proliferating tumor cells but also effectively eradicates BCSC-like cells in vitro and in vivo. Our findings warrant further investigation of FLU as a treatment for metastatic TNBC.

Overexpression of angiotensin II type 1 receptor in breast cancer cells induces epithelial-mesenchymal transition and promotes tumor growth and angiogenesis.

The angiotensin II type I receptor (AGTR1) has been implicated in diverse aspects of human disease, from the regulation of blood pressure and cardiovascular homeostasis to cancer progression. We sought to investigate the role of AGTR1 in cell proliferation, epithelial-mesenchymal transition (EMT), migration, invasion, angiogenesis and tumor growth in the breast cancer cell line MCF7. Stable overexpression of AGTR1 was associated with accelerated cell proliferation, concomitant with increased expression of survival factors including poly(ADP-ribose) polymerase (PARP) and X-linked inhibitor of apoptosis (XIAP), as well as extracellular signal-regulated kinase (ERK) activation. AGTR1-overexpressing MCF7 cells were more aggressive than their parent line, with significantly increased activity in migration and invasion assays. These observations were associated with changes in EMT markers, including reduced E-cadherin expression and increased p-Smad3, Smad4 and Snail levels. Treatment with the AGTR1 antagonist losartan attenuated these effects. AGTR1 overexpression also accelerated tumor growth and increased Ki-67 expression in a xenograft model. This was associated with increased tumor angiogenesis, as evidenced by a significant increase in microvessels in the intratumoral and peritumoral areas, and enhanced tumor invasion, with the latter response associated with increased EMT marker expression and matrix metallopeptidase 9 (MMP-9) upregulation. In vivo administration of losartan significantly reduced both tumor growth and angiogenesis. Our findings suggest that AGTR1 plays a significant role in tumor aggressiveness, and its inhibition may have therapeutic implications.

Disulfiram suppresses cancer stem-like properties and STAT3 signaling in triple-negative breast cancer cells.

In the presence of copper (Cu), disulfiram (DSF) suppresses properties associated with cancer stem cells (CSCs) in breast cancer, but the mechanism of action is poorly understood. In the present study, we observed that DSF/Cu treatment induced apoptosis, mediated by caspase-3 activation in triple-negative breast cancer (TNBC) cells. DSF/Cu treatment also specifically targeted CSC-like cell populations, marked by the inhibition of ALDH1 activity, the suppression of CD44+/CD24-and CD49f+/CD24 + subpopulations, and the subsequent impairment of mammosphere formation. These effects were functionally associated with a significant impact on the STAT3 signaling pathway, characterized by the downregulation of phospho-STAT3, cyclin D1 and survivin. In an MDA-MB-231-derived xenograft model, DSF administration significantly downregulated ALDH1A1, CD44 and phospho-STAT3 levels. These findings show for the first time that DSF suppresses stem-like properties in TNBC by targeting the STAT3 signaling pathway.

Salinomycin possesses anti-tumor activity and inhibits breast cancer stem-like cells via an apoptosis-independent pathway.

Cancer stem cells (CSCs) play important roles in the formation, growth and recurrence of tumors, particularly following therapeutic intervention. Salinomycin has received recent attention for its ability to target breast cancer stem cells (BCSCs), but the mechanisms of action involved are not fully understood. In the present study, we sought to investigate the mechanisms responsible for salinomycin's selective targeting of BCSCs and its anti-tumor activity. Salinomycin suppressed cell viability, concomitant with the downregulation of cyclin D1 and increased p27(kip1) nuclear accumulation. Mammosphere formation assays revealed that salinomycin suppresses self-renewal of ALDH1-positive BCSCs and downregulates the transcription factors Nanog, Oct4 and Sox2. TUNEL analysis of MDA-MB-231-derived xenografts revealed that salinomycin administration elicited a significant reduction in tumor growth with a marked downregulation of ALDH1 and CD44 levels, but seemingly without the induction of apoptosis. Our findings shed further light on the mechanisms responsible for salinomycin's effects on BCSCs.

Palmitate induces cisternal ER expansion via the activation of XBP-1/CCTα-mediated phospholipid accumulation in RAW 264.7 cells.

BACKGROUND: Endoplasmic reticulum (ER) stress induces ER expansion. The expansion of the intracisternal space of the ER was found in macrophages associated with human atherosclerotic lesions. We also previously reported that palmitate induces cisternal ER expansion and necrosis in RAW 264.7 cells. In this study, we report on an investigation of the likely mechanism responsible for this palmitate-induced cisternal ER expansion in a mouse macrophage cell line, RAW 264.7 cells. METHODS: RAW 264.7 cells were pre-treated with the designated inhibitor or siRNA, followed by treatment with palmitate. Changes in the ER structure were examined by transmission electron microscopy. The induction of ER stress was confirmed by an increase in the extent of phosphorylation of PERK, the expression of BiP and CHOP, and the splicing of XBP-1 mRNA. Phospholipid staining was performed with the LipidTOX Red phospholipidosis detection reagent. Related gene expressions were detected by quantitative real time-RT-PCR or RT-PCR. RESULTS: Palmitate was found to induce ER stress and cisternal ER expansion. In addition, palmitate-induced cisternal ER expansion was attenuated by ER stress inhibitors, such as 4-phenylbutyric acid (4-PBA) and tauroursodeoxycholic acid (TUDCA). The findings also show that palmitate induced-mRNA expression of CCTα, which increases phospholipid synthesis, was attenuated by the down-regulation of XBP-1, a part of ER stress. Furthermore, palmitate-induced phospholipid accumulation and cisternal ER expansion were attenuated by the down-regulation of XBP-1 or CCTα. CONCLUSIONS: The findings reported herein indicate that palmitate-induced cisternal ER expansion is dependent on the activation of XBP-1/CCTα-mediated phospholipid accumulation in RAW 264.7 cells.

Predominant D1 Receptors Involvement in the Over-expression of CART Peptides after Repeated Cocaine Administration.

The aim of this study was to investigate the involvement of dopaminergic receptors (DR) in behavioral sensitization, as measured by locomotor activity, and the over-expression of cocaine- and amphetamine-regulated transcript (CART) peptides after repeated administration of cocaine in mice. Repeated administrations of cocaine induced behavioral sensitization and CART over-expression in mice. The levels of striatal CART mRNA were significantly increased on the 3(rd) day. CART peptides were over-expressed on the 5(th) day in the striata of behaviorally sensitized mice. A higher proportion of CART(+) cells in the cocaine-treated mice were present in the nucleus accumbens (NAc) shell than in the dorsolateral (DL) part of caudate putamen (CP). The concomitant administration of both D1R and D2R antagonists, SCH 23390 (D1R selective) and raclopride (D2R selective), blocked cocaine induced-behavioral sensitization, CART over-expression, and cyclic adenosine 5'-monophosphate (cAMP)/protein kinase A (PKA)/phospho-cAMP response element-binding protein (pCREB) signal pathways. SCH 23390 more predominantly inhibited the locomotor activity, CART over-expression, pCREB and PKA activity than raclopride. Cocaine induced-behavioral sensitization was also attenuated in the both D1R and D2R knockout (KO) mice, respectively. CART over-expression and activated cAMP/PKA/pCREB signal pathways were inhibited in the D1R-KO mice, but not in the D2R-KO mice. It is suggested that behavioral sensitization, CART over-expression and activated cAMP/PKA/pCREB signal pathways induced by repeated administration of cocaine could be more predominantly mediated by D1R.

Caffeine induces behavioural sensitization and overexpression of cocaine-regulated and amphetamine-regulated transcript peptides in mice.

This study examined whether repeated administration of caffeine would induce behavioural sensitization and overexpression of cocaine-regulated and amphetamine-regulated transcript (CART) peptides in mice. The involvement of dopaminergic receptors and adenosine receptors in caffeine-induced behavioural sensitization and CART overexpression was studied. The relevance of D1R and D2R, and A1R and A(2A)R in the overexpression of CART peptides in mouse striatum was also evaluated. Repeated administration of caffeine induced behavioural sensitization in mice. Significant increases in CART mRNA levels were observed on day 3 and peaked at day 5 of caffeine administration, and then decreased gradually. Higher proportions of CART⁺ cells were observed in the dorsolateral and ventrolateral part of the caudate putamen than in the nucleus accumbens shell and core. The behavioural sensitization induced by caffeine was inhibited by dopaminergic receptor antagonists and adenosine receptor agonists. D1R and D2R, and cyclic AMP (cAMP)/protein kinase A (PKA)/phospho-cAMP response element-binding protein (pCREB) signalling were activated by caffeine, but A1R and A(2A)R were inhibited. Overexpression of caffeine-induced CART peptides and pCREB activity were blocked by N-cyclopentyladenosine (CPA, an A1R agonist) and 4-[2-[[6-amino-9-(N-ethyl-ß-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS 21680, an A(2A)R agonist), but not by R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH 23390, a D1R antagonist) or raclopride (a D2R antagonist). Caffeine-induced overexpression of CART peptides was associated with the inhibition of A1R and A(2A)R, and the activation of cAMP/PKA/pCREB signalling. Moreover, the A(2A)R-D2R heterodimer might be involved in the overexpression of CART peptides induced by caffeine.

Palmitate induced secretion of IL-6 and MCP-1 in orbital fibroblasts derived from patients with thyroid-associated ophthalmopathy.

PURPOSE: Orbital fibroblasts are now recognized as the key effectors in the development of thyroid associated ophthalmopathy (TAO). TAO is clinically apparent in approximately 50% of patients with Graves' hyperthyroidism. High levels of plasma free fatty acids (FFAs) are frequently seen in patients with hyperthyroidism. Palmitate is one of the most abundant FFAs in plasma and aggravates inflammation by promoting secretion of pro-inflammatory cytokines in various cells. In the present study, we characterized orbital fibroblasts from patients with TAO and then examined the effect of palmitate on the production of pro-inflammatory cytokines and hyaluronic acid (HA) in orbital fibroblasts. METHODS: Orbital fat explants were obtained from patients with TAO undergoing orbital decompression surgery (n=5). The fibroblasts were characterized by antibodies specific for fibroblast markers and Thy-1 (cluster differentiation 90, CD90) by immunostaining and flow cytometry. We then investigated the capability of orbital fibroblasts to secrete cytokines and HA in response to interleukin (IL)-1ß using an enzyme-linked immunosorbent assay (ELISA). The effect of palmitate on cytokine and HA production in orbital fibroblasts was examined at the protein level by ELISA and at the mRNA level by quantitative real time RT-PCR. The level of phosphorylation of mitogen-activated protein kinase (MAPK)s, including p38 MAPK (p38), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), was measured by immunoblot analysis. We then examined the role of MAPKs on palmitate-induced cytokine production using specific inhibitors to p38, ERK, and JNK, respectively. RESULTS: The orbital fibroblasts from patients with TAO were Thy-1- positive fibroblasts (>90%) with the ability to secrete IL-6, IL-8, monocyte chemotactic protein-1 (MCP-1), and HA in response to IL-1ß. Treatment with palmitate induced significant production of IL-6 and MCP-1, but not IL-8 and HA, in orbital fibroblasts. IL-6 and MCP-1 expression by palmitate were differentially regulated by MAPKs. IL-6 expression was mediated by the p38, ERK, JNK pathways, whereas MCP-1 expression was mediated by ERK and JNK, but not by p38, in palmitate-treated orbital fibroblasts. CONCLUSIONS: We show the possible involvement of palmitate in the promotion of inflammation within orbital tissues. This finding may be helpful for understanding the development of TAO in patients with hyperthyroidism.

Red ginseng extract attenuates kainate-induced excitotoxicity by antioxidative effects.

This study investigated the neuroprotective activity of red ginseng extract (RGE, Panax ginseng, C. A. Meyer) against kainic acid- (KA-) induced excitotoxicity in vitro and in vivo. In hippocampal cells, RGE inhibited KA-induced excitotoxicity in a dose-dependent manner as measured by the MTT assay. To study the possible mechanisms of the RGE-mediated neuroprotective effect against KA-induced cytotoxicity, we examined the levels of intracellular reactive oxygen species (ROS) and [Ca(2+)](i) in cultured hippocampal neurons and found that RGE treatment dose-dependently inhibited intracellular ROS and [Ca(2+)](i) elevation. Oral administration of RGE (30 and 200 mg/kg) in mice decreased the malondialdehyde (MDA) level induced by KA injection (30 mg/kg, i.p.). In addition, similar results were obtained after pretreatment with the radical scavengers Trolox and N, N'-dimethylthiourea (DMTU). Finally, after confirming the protective effect of RGE on hippocampal brain-derived neurotropic factor (BDNF) protein levels, we found that RGE is active compounds mixture in KA-induced hippocampal mossy-fiber function improvement. Furthermore, RGE eliminated 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and the IC(50) was approximately 10 mg/ml. The reductive activity of RGE, as measured by reaction with hydroxyl radical ((•)OH), was similar to trolox. The second-order rate constant of RGE for (•)OH was 3.5-4.5 × 10(9) M(-1)·S(-1). Therefore, these results indicate that RGE possesses radical reduction activity and alleviates KA-induced excitotoxicity by quenching ROS in hippocampal neurons.

Stress Experience of COVID-19 Patients as Reported by Psychological Supporters in South Korea: A Qualitative Study.

Background: COVID-19 patients experience various stressors during the quarantine period and after release from quarantine. However, stressors experienced during each period remain unclear. Methods: A total of 15 mental health experts from the integrated psychological support group for COVID-19participated in this study. Psychological support was provided for the total 932 confirmed COVID-19 patients and their families. Qualitative data were collected using Focus Group Interview (FGI). The participants were divided into two groups and semi-structured questions were used to allow participants to speak their minds. Results: During the quarantine period, difficulties of being diagnosed with COVID-19, concerns about recovery from COVID-19, stress related to quarantine, issues related to the treatment environment, and limited information about COVID-19 and communication were frequently reported. After release from quarantine, the reported main stressors include reinfection or reactivation, concerns about complications, and financial difficulties. Confusion as vectors and victims, stigma and discrimination, and conflicts within a family were observed during both periods. Conclusions: COVID-19 patients suffered various stressors during the quarantine period and after release from quarantine. Moreover, returning to their daily life required timely psychosocial support, intervention, and treatment for COVID-19 infection.

Evaluation of growth changes induced by functional appliances in children with Class II malocclusion: Superimposition of lateral cephalograms on stable structures.

OBJECTIVE: To compare short- and long-term dentoalveolar, skeletal, and rotational changes evaluated by Björk's structural method of superimposition between children with Class II malocclusion treated by functional appliances and untreated matched controls. METHODS: Seventy-nine prepubertal or pubertal children (mean age, 11.57 ± 1.40 years) with Class II malocclusion were included. Thirty-four children were treated using an activator with a high-pull headgear (Z-activator), while 28 were treated using an activator without a headgear (E-activator). Seventeen untreated children were included as controls. Lateral cephalograms were obtained before treatment (T1), after functional appliance treatment (T2), and after retention in the postpubertal phase (T3). Changes from T1 to T2 and T1 to T3 were compared between the treated groups and control group using multiple linear regression analysis. RESULTS: Relative to the findings in the control group at T2, the sagittal jaw relationship (subspinale-nasion- pogonion, p < 0.001), maxillary prognathism (sella-nasion-subspinale, p < 0.05), and condylar growth (p < 0.001) exhibited significant improvements in the Z- and E-activator groups, which also showed a significantly increased maxillary incisor retraction (p < 0.001) and decreased overjet (p < 0.001). Only the E-activator group exhibited significant backward rotation of the maxilla at T2 (p < 0.01). The improvements in the sagittal jaw relationship (p < 0.01) and dental relationship (p < 0.001) remained significant at T3. Condylar growth and jaw rotations were not significant at T3. CONCLUSIONS: Functional appliance treatment in children with Class II malocclusion can significantly improve the sagittal jaw relationship and dental relationships in the long term.

C-terminal HSP90 inhibitor L80 elicits anti-metastatic effects in triple-negative breast cancer via STAT3 inhibition.

Triple-negative breast cancer (TNBC) is an aggressive heterogeneous disease with a divergent profile. It has an earlier tendency to form metastases and is associated with poor clinical outcomes due to the limited treatment options available. Heat-shock protein (HSP90) represents a potential treatment target as it promotes tumor progression and metastasis by modulating the maturation and stabilization of signal transduction proteins. We sought to investigate the efficacy of the C-terminal HSP90 inhibitor L80 on cell proliferation, breast cancer stem cell (BCSC)-like properties, tumor growth and metastasis. L80 suppressed cell viability and concomitantly inhibited AKT/MEK/ERK/JAK2/STAT3 signaling in TNBC cells but did not induce cytotoxicity in normal cells. L80 effectively targeted BCSC-like traits, together with significant reductions in the CD44high/CD24low-population, ALDH1 activity and mammosphere forming-ability. In support of the in vitro observations, L80 administration caused significant impairment in tumor growth, angiogenesis and distant metastases in an orthotopic allograft model with BCSC-enriched cells in vivo. These phenomena were associated with the suppression of BCSC-like characteristics and STAT3 dysfunction. Our findings highlight properties of the L80 compound that may be useful in suppressing metastatic TNBC.

Ethnic differences in craniofacial and upper spine morphology in children with skeletal Class II malocclusion.

OBJECTIVES: To analyze differences in upper cervical spine and craniofacial morphology, including posterior cranial fossa and growth prediction signs, between Danish and South Korean pre-orthodontic skeletal Class II children and to analyze associations between upper cervical spine morphology and craniofacial characteristics. MATERIALS AND METHODS: One hundred forty-six skeletal Class II children-93 Danes (54 boys and 39 girls, mean age 12.2 years) and 53 Koreans (27 boys and 26 girls, mean age 10.8 years)-were included. Upper spine morphology, Atlas dimensions, and craniofacial morphology, including posterior cranial fossa and growth prediction signs, were assessed on lateral cephalograms. Differences and associations were analyzed by multiple linear and logistic regression analyses adjusted for age and gender. RESULTS: Significant differences between the ethnic groups were found in the sagittal and vertical craniofacial dimensions ( P < .001), mandibular shape ( P < .01), dental relationship ( P < .01), posterior cranial fossa ( P < .05), and growth prediction signs ( P < .001). No significant differences were found in upper spine morphology and Atlas dimensions between the groups. Upper spine morphology/dimensions were significantly associated with the cranial base angle ( P < .01), sagittal craniofacial dimensions ( P < .001), posterior cranial fossa ( P < .001), and growth prediction signs ( P < .05). CONCLUSIONS: Upper spine morphology/dimensions may be valuable as predictive factors in treatment planning for growing Class II children.

Flubendazole overcomes trastuzumab resistance by targeting cancer stem-like properties and HER2 signaling in HER2-positive breast cancer.

Although trastuzumab provides significant clinical benefit for HER2-positive breast cancers, responses are limited by the emergence of resistance. Trastuzumab resistance is a multi-factorial phenomenon thought to arise from the presence of cancer stem cells and interactions between truncated p95HER2 and HER family members. Flubendazole (FLU) is a potent anthelmintic agent with an exceptional safety profile. Evidence also suggests that it can act as an anticancer agent in several cancer cell types. We sought to investigate the effect of FLU on apoptosis, HER2/Akt signaling, breast cancer stem cell (BCSC)-like properties and trastuzumab resistance in HER2-positive breast cancer cells. FLU treatment induced apoptosis, associated with a significant downregulation of truncated p95HER2, phospho-HER2, phospho-HER3 and phospho-Akt levels, as well as suppression of HER2/HER3 hetero-dimerization in both trastuzumab-sensitive and -resistant lines. FLU effectively targeted BCSC-like properties including aldehyde dehydrogenase 1 (ALDH1) expression and the CD44high/CD24low phenotype, concomitant with a suppression of mammosphere-forming ability. FLU administration also caused significant tumor suppression in trastuzumab-resistant xenografts, coinciding with the downregulation of BCSC-related markers and intracellular HER2. These findings highlight the mechanisms of action of FLU in overcoming trastuzumab resistance in breast cancer.

Vancomycin-induced morphological transformation of self-assembled amphiphilic diacetylene supramolecules.

Reversible ribbon-sphere microstructural transformation of dipeptide-containing diacetylene supramolecules was observed by specific ligand-receptor interactions.

Inhibition of ubiquitin-specific protease 34 (USP34) induces epithelial-mesenchymal transition and promotes stemness in mammary epithelial cells.

Ubiquitin-specific protease 34 (USP34) is a deubiquitinating enzyme that regulates Axin stability and plays a critical role in Wnt/ß-catenin signaling. We sought to investigate the role of USP34 on epithelial-mesenchymal (EMT) induction and its effects on mammary epithelial stem cells. USP34 expression levels were relatively lower in MDA-MB-231 and 4T1 mesenchymal-like cells when compared to epithelial-like cells. Inhibition of USP34 in NMuMG cells induced EMT, as evidenced by the upregulation of EMT markers including N-cadherin, phospho-Smad3, Snail and active-ß-catenin, as well as the downregulation of Axin 1 and E-cadherin. USP34 knockdown (KD) in these cells also resulted in the acquisition of invasive behavior, and promoted stemness as indicated by enhanced mammosphere-forming ability, concomitant with the upregulation of Nanog, Oct4 and Sox2 mRNA expression. Endogenous USP34 expression was observed to be at low levels in virgin mouse mammary glands in vivo. When USP34-KD cells were transplanted into the cleared mammary fat pads (CFP) of mice, these cells reconstituted the mammary gland with ductal tree development within 3months. Our findings suggest a previously unknown role for USP34 in mammary gland development.