Prevalence, proportions of elevated liver enzyme levels, and long-term cardiometabolic mortality of patients with metabolic dysfunction-associated steatotic liver disease.

BACKGROUND AND AIM: This study estimated the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) according to cardiometabolic risk factors. The long-term impacts of MASLD on all-cause and cardiometabolic-specific mortality were evaluated. METHODS: We enrolled 343 816 adults aged ≥30 years who participated in a health screening program from 1997 through 2013. MASLD was identified on the basis of abdominal ultrasonography and metabolic profiles. The participants were further categorized by liver enzyme elevation. Baseline cardiometabolic comorbidities were classified on the basis of self-reported medication use and clinical seromarkers. All-cause and cardiometabolic-specific deaths were determined through computerized data linkage with nationwide death certifications until December 31, 2020. RESULTS: The overall prevalence of MASLD was 36.4%. Among patients with MASLD, 35.9% had abnormal liver enzyme levels. Compared with patients without MASLD, abnormal liver enzymes were positively associated with cardiometabolic comorbidities in patients with MASLD (Pfor trend < 0.001). After follow-up, patients with MASLD had a 9%-29% higher risk of all-cause, cardiovascular-related, or diabetes-related mortality. In the groups with MASLD and elevated and normal liver enzyme levels, the multivariate-adjusted hazard ratios for cardiovascular deaths were 1.14 (1.05-1.25) and 1.10 (1.03-1.17), respectively, and those for diabetes deaths were 1.42 (1.05-1.93) and 1.24 (0.98-1.57), respectively, compared with those in the non-MASLD group (Pfor trend < 0.001). DISCUSSION: Individuals with MASLD and elevated liver enzyme levels exhibited significantly higher risks of all-cause and cardiometabolic deaths and should be monitored and given consultation on cardiometabolic modifications.

Parasympathetic neurons derived from human pluripotent stem cells model human diseases and development.

Autonomic parasympathetic neurons (parasymNs) control unconscious body responses, including "rest-and-digest." ParasymN innervation is important for organ development, and parasymN dysfunction is a hallmark of autonomic neuropathy. However, parasymN function and dysfunction in humans are vastly understudied due to the lack of a model system. Human pluripotent stem cell (hPSC)-derived neurons can fill this void as a versatile platform. Here, we developed a differentiation paradigm detailing the derivation of functional human parasymNs from Schwann cell progenitors. We employ these neurons (1) to assess human autonomic nervous system (ANS) development, (2) to model neuropathy in the genetic disorder familial dysautonomia (FD), (3) to show parasymN dysfunction during SARS-CoV-2 infection, (4) to model the autoimmune disease Sjögren's syndrome (SS), and (5) to show that parasymNs innervate white adipocytes (WATs) during development and promote WAT maturation. Our model system could become instrumental for future disease modeling and drug discovery studies, as well as for human developmental studies.

Long-term Risks of Cirrhosis and Hepatocellular Carcinoma Across Steatotic Liver Disease Subtypes.

INTRODUCTION: The prospective study aimed to investigate the long-term associated risks of cirrhosis and hepatocellular carcinoma (HCC) across various subtypes of steatotic liver disease (SLD). METHODS: We enrolled 332,175 adults who participated in a health screening program between 1997 and 2013. Participants were categorized into various subtypes, including metabolic dysfunction-associated SLD (MASLD), MASLD with excessive alcohol consumption (MetALD), and alcohol-related liver disease (ALD), based on ultrasonography findings, alcohol consumption patterns, and cardiometabolic risk factors. We used computerized data linkage with nationwide registries from 1997 to 2019 to ascertain the incidence of cirrhosis and HCC. RESULTS: After a median follow-up of 16 years, 4,458 cases of cirrhosis and 1,392 cases of HCC occurred in the entire cohort, resulting in an incidence rate of 86.1 and 26.8 per 100,000 person-years, respectively. The ALD group exhibited the highest incidence rate for cirrhosis and HCC, followed by MetALD, MASLD, and non-SLD groups. The multivariate adjusted hazard ratios for HCC were 1.92 (95% confidence interval [CI] 1.51-2.44), 2.91 (95% CI 2.11-4.03), and 2.59 (95% CI 1.93-3.48) for MASLD, MetALD, and ALD, respectively, when compared with non-SLD without cardiometabolic risk factors. The pattern of the associated risk of cirrhosis was similar to that of HCC (all P value <0.001). The associated risk of cirrhosis for ALD increased to 4.74 (95% CI 4.08-5.52) when using non-SLD without cardiometabolic risk factors as a reference. DISCUSSION: This study highlights elevated risks of cirrhosis and HCC across various subtypes of SLD compared with non-SLD, emphasizing the importance of behavioral modifications for early prevention.

Novel lissencephaly-associated NDEL1 variant reveals distinct roles of NDE1 and NDEL1 in nucleokinesis and human cortical malformations.

The development of the cerebral cortex involves a series of dynamic events, including cell proliferation and migration, which rely on the motor protein dynein and its regulators NDE1 and NDEL1. While the loss of function in NDE1 leads to microcephaly-related malformations of cortical development (MCDs), NDEL1 variants have not been detected in MCD patients. Here, we identified two patients with pachygyria, with or without subcortical band heterotopia (SBH), carrying the same de novo somatic mosaic NDEL1 variant, p.Arg105Pro (p.R105P). Through single-cell RNA sequencing and spatial transcriptomic analysis, we observed complementary expression of Nde1/NDE1 and Ndel1/NDEL1 in neural progenitors and post-mitotic neurons, respectively. Ndel1 knockdown by in utero electroporation resulted in impaired neuronal migration, a phenotype that could not be rescued by p.R105P. Remarkably, p.R105P expression alone strongly disrupted neuronal migration, increased the length of the leading process, and impaired nucleus-centrosome coupling, suggesting a failure in nucleokinesis. Mechanistically, p.R105P disrupted NDEL1 binding to the dynein regulator LIS1. This study identifies the first lissencephaly-associated NDEL1 variant and sheds light on the distinct roles of NDE1 and NDEL1 in nucleokinesis and MCD pathogenesis.

Regulation of Primary Cilium Length by O-GlcNAc during Neuronal Development in a Human Neuron Model.

The primary cilium plays critical roles in the homeostasis and development of neurons. Recent studies demonstrate that cilium length is regulated by the metabolic state of cells, as dictated by processes such as glucose flux and O-GlcNAcylation (OGN). The study of cilium length regulation during neuron development, however, has been an area left largely unexplored. This project aims to elucidate the roles of O-GlcNAc in neuronal development through its regulation of the primary cilium. Here, we present findings suggesting that OGN levels negatively regulate cilium length on differentiated cortical neurons derived from human-induced pluripotent stem cells. In neurons, cilium length increased significantly during maturation (after day 35), while OGN levels began to drop. Long-term perturbation of OGN via drugs, which inhibit or promote its cycling, during neuron development also have varying effects. Diminishing OGN levels increases cilium length until day 25, when neural stem cells expand and undergo early neurogenesis, before causing cell cycle exit defects and multinucleation. Elevating OGN levels induces greater primary cilia assembly but ultimately results in the development of premature neurons, which have higher insulin sensitivity. These results indicate that OGN levels and primary cilium length are jointly critical in proper neuron development and function. Understanding the interplays between these two nutrient sensors, O-GlcNAc and the primary cilium, during neuron development is important in paving connections between dysfunctional nutrient-sensing and early neurological disorders.

O-GlcNAcylation is crucial for sympathetic neuron development, maintenance, functionality and contributes to peripheral neuropathy.

O-GlcNAcylation is a post-translational modification (PTM) that regulates a wide range of cellular functions and has been associated with multiple metabolic diseases in various organs. The sympathetic nervous system (SNS) is the efferent portion of the autonomic nervous system that regulates metabolism of almost all organs in the body. How much the development and functionality of the SNS are influenced by O-GlcNAcylation, as well as how such regulation could contribute to sympathetic neuron (symN)-related neuropathy in diseased states, remains unknown. Here, we assessed the level of protein O-GlcNAcylation at various stages of symN development, using a human pluripotent stem cell (hPSC)-based symN differentiation paradigm. We found that pharmacological disruption of O-GlcNAcylation impaired both the growth and survival of hPSC-derived symNs. In the high glucose condition that mimics hyperglycemia, hPSC-derived symNs were hyperactive, and their regenerative capacity was impaired, which resembled typical neuronal defects in patients and animal models of diabetes mellitus. Using this model of sympathetic neuropathy, we discovered that O-GlcNAcylation increased in symNs under high glucose, which lead to hyperactivity. Pharmacological inhibition of O-GlcNAcylation rescued high glucose-induced symN hyperactivity and cell stress. This framework provides the first insight into the roles of O-GlcNAcylation in both healthy and diseased human symNs and may be used as a platform for therapeutic studies.

Low glucose induced Alzheimer's disease-like biochemical changes in human induced pluripotent stem cell-derived neurons is due to dysregulated O-GlcNAcylation.

INTRODUCTION: Sporadic Alzheimer's disease (sAD) is the leading type of dementia. Brain glucose hypometabolism, along with decreased O-GlcNAcylation levels, occurs before the onset of symptoms and correlates with pathogenesis. Heretofore, the mechanisms involved and the roles of O-GlcNAcylation in sAD pathology largely remain unknown due to a lack of human models of sAD. METHODS: Human cortical neurons were generated from pluripotent stem cells (PSCs) and treated with glucose reduction media. RESULTS: We found a narrow window of glucose concentration that induces sAD-like phenotypes in PSC-derived neurons. With our model, we reveal that dysregulated O-GlcNAc, in part through mitochondrial dysfunction, causes the onset of sAD-like changes. We demonstrate the therapeutic potential of inhibiting O-GlcNAcase in alleviating AD-like biochemical changes. DISCUSSION: Our results suggest that dysregulated O-GlcNAc might be a direct molecular link between hypometabolism and sAD-like alternations. Moreover, this model can be exploited to explore molecular processes and for drug development. HIGHLIGHTS: Lowering glucose to a critical level causes AD-like changes in cortical neurons. Defective neuronal structure and function were also recapitulated in current model. Dysregulated O-GlcNAcylation links impaired glucose metabolism to AD-like changes. Mitochondrial abnormalities correlate with O-GlcNAcylation and precede AD-like phenotype. Our model provides a platform to study sAD as a metabolic disease in human neurons.

Muscleblind-like 2 knockout shifts adducin 1 isoform expression and alters dendritic spine dynamics of cortical neurons during brain development.

AIMS: Muscleblind-like 2 (MBNL2) plays a crucial role in regulating alternative splicing during development and mouse loss of MBNL2 recapitulates brain phenotypes in myotonic dystrophy (DM). However, the mechanisms underlying DM neuropathogenesis during brain development remain unclear. In this study, we aim to investigate the impact of MBNL2 elimination on neuronal development by Mbnl2 conditional knockout (CKO) mouse models. METHODS: To create Mbnl2 knockout neurons, cDNA encoding Cre-recombinase was delivered into neural progenitors of Mbnl2flox/flox mouse brains by in utero electroporation. The morphologies and dynamics of dendritic spines were monitored by confocal and two-photon microscopy in brain slices and live animals from the neonatal period into adulthood. To investigate the underlying molecular mechanism, we further detected the changes in the splicing and molecular interactions of proteins associated with spinogenesis. RESULTS: We found that Mbnl2 knockout in cortical neurons decreased dendritic spine density and dynamics in adolescent mice. Mbnl2 ablation caused the adducin 1 (ADD1) isoform to switch from adult to fetal with a frameshift, and the truncated ADD1 failed to interact with alpha-II spectrin (SPTAN1), a critical protein for spinogenesis. In addition, expression of ADD1 adult isoform compensated for the reduced dendritic spine density in cortical neurons deprived of MBNL2. CONCLUSION: MBNL2 plays a critical role in maintaining the dynamics and homeostasis of dendritic spines in the developing brain. Mis-splicing of downstream ADD1 may account for the alterations and contribute to the DM brain pathogenesis.

Altered O-GlcNAcylation and mitochondrial dysfunction, a molecular link between brain glucose dysregulation and sporadic Alzheimer's disease.

Alzheimer's disease is a neurodegenerative disease that affected over 6.5 million people in the United States in 2021, with this number expected to double in the next 40 years without any sort of treatment. Due to its heterogeneity and complexity, the etiology of Alzheimer's disease, especially sporadic Alzheimer's disease, remains largely unclear. Compelling evidence suggests that brain glucose hypometabolism, preceding Alzheimer's disease hallmarks, is involved in the pathogenesis of Alzheimer's disease. Herein, we discuss the potential causes of reduced glucose uptake and the mechanisms underlying glucose hypometabolism and Alzheimer's disease pathology. Specifically, decreased O-GlcNAcylation levels by glucose deficiency alter mitochondrial functions and together contribute to Alzheimer's disease pathogenesis. One major problem with Alzheimer's disease research is that the disease progresses for several years before the onset of any symptoms, suggesting the critical need for appropriate models to study the molecular changes in the early phase of Alzheimer's disease progression. Therefore, this review also discusses current available sporadic Alzheimer's disease models induced by metabolic abnormalities and provides novel directions for establishing a human neuronal sporadic Alzheimer's disease model that better represents human sporadic Alzheimer's disease as a metabolic disease.

Norepinephrine transporter defects lead to sympathetic hyperactivity in Familial Dysautonomia models.

Familial dysautonomia (FD), a rare neurodevelopmental and neurodegenerative disorder affects the sympathetic and sensory nervous system. Although almost all patients harbor a mutation in ELP1, it remains unresolved exactly how function of sympathetic neurons (symNs) is affected; knowledge critical for understanding debilitating disease hallmarks, including cardiovascular instability or dysautonomic crises, that result from dysregulated sympathetic activity. Here, we employ the human pluripotent stem cell (hPSC) system to understand symN disease mechanisms and test candidate drugs. FD symNs are intrinsically hyperactive in vitro, in cardiomyocyte co-cultures, and in animal models. We report reduced norepinephrine transporter expression, decreased intracellular norepinephrine (NE), decreased NE re-uptake, and excessive extracellular NE in FD symNs. SymN hyperactivity is not a direct ELP1 mutation result, but may connect to NET via RAB proteins. We found that candidate drugs lowered hyperactivity independent of ELP1 modulation. Our findings may have implications for other symN disorders and may allow future drug testing and discovery.

Near-infrared spectroscopy using period-chirped Si/SiO/SiO2-based guided mode resonance filter.

We demonstrate a Si/SiO/SiO2-based period-chirped guided mode resonance (GMR) filter to discriminate telecom o-band wavelengths by spatially resolved horizontal movement. Continuously period-chirped silicon gratings were fabricated by using a Lloyd's laser interferometer with a convex mirror. Due to the large waveguide effective index, the GMR filter can be realized with a short grating period, thus enabling a slow grating period transition along the sample position and high optical resolution in wavelength discrimination. Depositing a SiO/SiO2 stack on top of silicon gratings enables a narrowband GMR filter with a linewidth of 1-1.5 nm over a wavelength range of 1260-1360 nm. By using the chirped GMR filter as a dispersive device, the optical spectra of a near-infrared broadband light source are reconstructed. An optimized aspheric mirror is proposed to further improve the linearity of chirped gratings. Such a period-chirped GMR filter is promising for compact on-chip spectroscopy and sensing applications.

A Novel Spo11 Homologue Functions as a Positive Regulator in Cyst Differentiation in Giardia lamblia.

Giardia lamblia persists in a dormant state with a protective cyst wall for transmission. It is incompletely known how three cyst wall proteins (CWPs) are coordinately synthesized during encystation. Meiotic recombination is required for sexual reproduction in animals, fungi, and plants. It is initiated by formation of double-stranded breaks by a topoisomerase-like Spo11. It has been shown that exchange of genetic material in the fused nuclei occurs during Giardia encystation, suggesting parasexual recombination processes of this protozoan. Giardia possesses an evolutionarily conserved Spo11 with typical domains for cleavage reaction and an upregulated expression pattern during encystation. In this study, we asked whether Spo11 can activate encystation process, like other topoisomerases we previously characterized. We found that Spo11 was capable of binding to both single-stranded and double-stranded DNA in vitro and that it could also bind to the cwp promoters in vivo as accessed in chromatin immunoprecipitation assays. Spo11 interacted with WRKY and MYB2 (named from myeloblastosis), transcription factors that can activate cwp gene expression during encystation. Interestingly, overexpression of Spo11 resulted in increased expression of cwp1-3 and myb2 genes and cyst formation. Mutation of the Tyr residue for the active site or two conserved residues corresponding to key DNA-binding residues for Arabidopsis Spo11 reduced the levels of cwp1-3 and myb2 gene expression and cyst formation. Targeted disruption of spo11 gene with CRISPR/Cas9 system led to a significant decrease in cwp1-3 and myb2 gene expression and cyst number. Our results suggest that Spo11 acts as a positive regulator for Giardia differentiation into cyst.

Visible-Light-Assisted Photoelectrochemical Biosensing of Uric Acid Using Metal-Free Graphene Oxide Nanoribbons.

In this study, we demonstrate the visible-light-assisted photoelectrochemical (PEC) biosensing of uric acid (UA) by using graphene oxide nanoribbons (GONRs) as PEC electrode materials. Specifically, GONRs with controlled properties were synthesized by the microwave-assisted exfoliation of multi-walled carbon nanotubes. For the detection of UA, GONRs were adopted to modify either a screen-printed carbon electrode (SPCE) or a glassy carbon electrode (GCE). Cyclic voltammetry analyses indicated that all Faradaic currents of UA oxidation on GONRs with different unzipping/exfoliating levels on SPCE increased by more than 20.0% under AM 1.5 irradiation. Among these, the GONRs synthesized under a microwave power of 200 W, namely GONR(200 W), exhibited the highest increase in Faradaic current. Notably, the GONR(200 W)/GCE electrodes revealed a remarkable elevation (~40.0%) of the Faradaic current when irradiated by light-emitting diode (LED) light sources under an intensity of illumination of 80 mW/cm2. Therefore, it is believed that our GONRs hold great potential for developing a novel platform for PEC biosensing.

Effects of temperature and repeat layer spacing on mechanical properties of graphene/polycrystalline copper nanolaminated composites under shear loading.

In the present study, the characteristics of graphene/polycrystalline copper nanolaminated (GPCuNL) composites under shear loading are investigated by molecular dynamics simulations. The effects of different temperatures, graphene chirality, repeat layer spacing, and grain size on the mechanical properties, such as failure mechanism, dislocation, and shear modulus, are observed. The results indicate that as the temperature increases, the content of Shockley dislocations will increase and the maximum shear stress of the zigzag and armchair directions also decreases. The mechanical strength of the zigzag direction is more dependent on the temperature than that of the armchair direction. Moreover, self-healing occurs in the armchair direction, which causes the shear stress to increase after failure. Furthermore, the maximum shear stress and the shear strength of the composites decrease with an increase of the repeat layer spacing. Also, the shear modulus increases by increasing the grain size of copper.

Polarization-controlled chirped guided-mode resonance filter incorporating a hybrid splay-twist liquid crystal.

This work develops a tunable chirped guided-mode resonant (GMR) filter that has a hybrid splay-twist (HST) liquid crystal as a cladding layer. The GMR filter is a color reflector that strongly reflects light at the resonance wavelength, and its chirped grating structure supports tuning of the resonance peak over a wavelength range of over 50 nm. The HST-LC configuration serves as an achromatic polarization rotator that can rotate the axis of polarization of linearly polarized light by providing effective twist angles in the LC layer under an applied voltage. The HST-LC is used to change the direction of the polarization axis of the light that is reflected by the GMR filter; continuous angles of rotation of ∼90∘ are achieved and the linear polarization is retained under applied voltages. The proposed filter enables an ultrabroadband polarization rotation and still maintains a high degree of linear polarization, which allows more degrees of freedom in spectral and polarization controls.

Reduction in MicroRNA-4488 Expression Induces NFκB Translocation in Venous Endothelial Cells Under Arterial Flow.

PURPOSE: Little is known about the molecular interactions among inflammatory responses that damage venous endothelial cells (vECs) during venous-to-arterial flow transition in vein graft diseases. Because arterial flow triggers excessive autophagy and inflammation in vECs, this study aimed to investigate the mediator of inflammation and methods to prevent vEC damage. METHODS: Arterial laminar shear stress (ALSS; 12 dynes/cm2) was applied to vECs via in vitro and ex vivo perfusion systems. Inflammation in vECs was measured using inflammatory protein markers, NFκB translocation, cyclooxygenase-2 (COX-2) and COX-2 and NFκB promoter assays. The involvement of microRNA-4488 (miR-4488) was measured and confirmed by altering the specific miR using a miR-4488 mimic or inhibitor. The potential anti-inflammatory drugs and/or nitric oxide (NO) donor L-arginine (L-Arg) to prevent damage to vECs under ALSS was investigated. RESULTS: ALSS triggered reactive oxygen species production, excessive autophagy, COX-2 protein expression, and NFκB translocation during vEC inflammation. Reduction in miR-4488 expression was detected in inflamed vECs treated with LPS, lipopolysaccharide (LPS) TNFα, and ALSS. Transfection of miR-4488 mimic (50 nM) prior to ALSS application inhibited the accumulation of inflammatory proteins as well as the translocation of NFκB. Combined treatment of vECs with COX-2-specific inhibitor (SC-236) and L-Arg alleviated the ALSS-induced inflammatory responses. Protective effects of the combined treatment on vECs against ALSS-induced damage were abolished by the application of miR-4488 inhibitor. CONCLUSION: We showed that ALSS triggered the COX-2/NFκB pathway to induce vEC inflammation with a reduction in miR-4488. Combination of SC-236 and L-Arg prevented ALSS-induced vEC damage, thus, shows high potential for preventing vein graft diseases.

Curcumol Suppresses Triple-negative Breast Cancer Metastasis by Attenuating Anoikis Resistance via Inhibition of Skp2-mediated Transcriptional Addiction.

BACKGROUND/AIM: Triple-negative breast cancer (TNBC) is a unique subtype that lacks expression of several conventional biomarkers and has a higher incidence of lymph node invasion and distal metastasis among all breast cancers. Anoikis resistance is the fundamental reason behind tumor cells' survival without their attachment to the extracellular matrix and metastasis to distal organs. Therefore, finding novel anti-cancer drugs that can suppress anoikis resistance in cancer cells is critical for patients with TNBC. MATERIALS AND METHODS: Curcumol, a natural compound, was used to assess whether it can inhibit the anoikis resistance and affects cell mortality and motility of IV2-1 TNBC cells. RESULTS: Curcumol suppressed anoikis resistance and inhibited TNBC cell survival in suspension. Additionally, these anti-cancer effects induced by curcumol could be related to the YAP1/Skp2 molecular pathway. CONCLUSION: Curcumol is an effective Skp2-targeted therapy that attenuates anoikis resistance and metastasis in TNBC cells.

FGF9 induces functional differentiation to Schwann cells from human adipose derived stem cells.

Rationale: The formation of adipose-derived stem cells (ASCs) into spheres on a chitosan-coated microenvironment promoted ASCs differentiation into a mixed population of neural lineage-like cells (NLCs), but the underline mechanism is still unknown. Since the fibroblast growth factor 9 (FGF9) and fibroblast growth factor receptors (FGFRs) play as key regulators of neural cell fate during embryo development and stem cell differentiation, the current study aims to reveal the interplay of FGF9 and FGFRs for promoting peripheral nerve regeneration. Methods: Different concentration of FGF9 peptide (10, 25, 50, 100 ng/mL) were added during NLCs induction (FGF9-NLCs). The FGFR expressions and potential signaling were studied by gene and protein expressions as well as knocking down by specific FGFR siRNA or commercial inhibitors. FGF9-NLCs were fluorescent labeled and applied into a nerve conduit upon the injured sciatic nerves of experimental rats. Results: The FGFR2 and FGFR4 were significantly increased during NLCs induction. The FGF9 treated FGF9-NLCs spheres became smaller and changed into Schwann cells (SCs) which expressed S100ß and GFAP. The specific silencing of FGFR2 diminished FGF9-induced Akt phosphorylation and inhibited the differentiation of SCs. Transplanted FGF9-NLCs participated in myelin sheath formation, enhanced axonal regrowth and promoted innervated muscle regeneration. The knockdown of FGFR2 in FGF9-NLCs led to the abolishment of nerve regeneration. Conclusions: Our data therefore demonstrate the importance of FGF9 in the determination of SC fate via the FGF9-FGFR2-Akt pathway and reveal the therapeutic benefit of FGF9-NLCs.

The CDK6-c-Jun-Sp1-MMP-2 axis as a biomarker and therapeutic target for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) has high metastatic, drug-resistance, and recurrence rates, and is characterized by an angiogenic and fibrotic microenvironment that favors cancer malignancy. However, details of the mechanisms underlying malignancy are still largely unknown. Our mouse model indicated that knockdown of CDK6 inhibited lung metastasis significantly compared to parental cells. Immunohistochemical analyses revealed that the levels of collagen and the angiogenic marker matrix metalloproteinase (MMP)-2 were much lower in CDK6-deficient cells. To examine mechanisms in the CDK6-mediated phenotype of cancer cells, we studied its role in MMP-2 expression. CDK6 mediated the recruitment of transcription factors including c-Jun and Sp1 to the MMP2 promoter. Knockdown of CDK6 significantly suppressed the expression of MMP2 mRNA. Consistent with the in vitro data, the expression of CDK6 was positively correlated with the angiogenic and fibrotic tumor microenvironment in TNBC patient tissues as shown by MMP-2 and fibronectin staining, respectively. More importantly, after screening a small molecule library of 31 protein kinase inhibitors, we found that the Raf inhibitor sorafenib displayed the highest cytotoxicity in CDK6-depleted cells. These data indicate that CDK6 serves as an anti-microenvironment target and affects the drug response in retinoblastoma-proficient TNBC, suggesting that combining a CDK6 inhibitor and sorafenib leads to a synthetic effect that may represent a personalized therapeutic approach for patients with TNBC.