Enhancement of the therapeutic efficacy of the MAP regimen using thiamine pyrophosphate-decorated albumin nanoclusters in osteosarcoma treatment.

Recent studies on osteosarcoma regimens have mainly focused on modifying the combination of antineoplastic agents rather than enhancing the therapeutic efficacy of each component. Here, an albumin nanocluster (NC)-assisted methotrexate (MTX), doxorubicin (DOX), and cisplatin (MAP) regimen with improved antitumor efficacy is presented. Human serum albumin (HSA) is decorated with thiamine pyrophosphate (TPP) to increase the affinity to the bone tumor microenvironment (TME). MTX or DOX (hydrophobic MAP components) is adsorbed to HSA-TPP via hydrophobic interactions. MTX- or DOX-adsorbed HSA-TPP NCs exhibit 20.8- and 1.64-fold higher binding affinity to hydroxyapatite, respectively, than corresponding HSA NCs, suggesting improved targeting ability to the bone TME via TPP decoration. A modified MAP regimen consisting of MTX- or DOX-adsorbed HSA-TPP NCs and free cisplatin displays a higher synergistic anticancer effect in HOS/MNNG human osteosarcoma cells than conventional MAP. TPP-decorated NCs show 1.53-fold higher tumor accumulation than unmodified NCs in an orthotopic osteosarcoma mouse model, indicating increased bone tumor distribution. As a result, the modified regimen more significantly suppresses tumor growth in vivo than solution-based conventional MAP, suggesting that HSA-TPP NC-assisted MAP may be a promising strategy for osteosarcoma treatment.

Small-molecule targeting of GPCR-independent noncanonical G-protein signaling in cancer.

Activation of heterotrimeric G-proteins (Gαßγ) by G-protein-coupled receptors (GPCRs) is a quintessential mechanism of cell signaling widely targeted by clinically approved drugs. However, it has become evident that heterotrimeric G-proteins can also be activated via GPCR-independent mechanisms that remain untapped as pharmacological targets. GIV/Girdin has emerged as a prototypical non-GPCR activator of G proteins that promotes cancer metastasis. Here, we introduce IGGi-11, a first-in-class small-molecule inhibitor of noncanonical activation of heterotrimeric G-protein signaling. IGGi-11 binding to G-protein α-subunits (Gαi) specifically disrupted their engagement with GIV/Girdin, thereby blocking noncanonical G-protein signaling in tumor cells and inhibiting proinvasive traits of metastatic cancer cells. In contrast, IGGi-11 did not interfere with canonical G-protein signaling mechanisms triggered by GPCRs. By revealing that small molecules can selectively disable noncanonical mechanisms of G-protein activation dysregulated in disease, these findings warrant the exploration of therapeutic modalities in G-protein signaling that go beyond targeting GPCRs.

Small-molecule targeting of GPCR-independent non-canonical G protein signaling inhibits cancer progression.

Activation of heterotrimeric G-proteins (Gαßγ) by G-protein-coupled receptors (GPCRs) is a quintessential mechanism of cell signaling widely targeted by clinically-approved drugs. However, it has become evident that heterotrimeric G-proteins can also be activated via GPCR-independent mechanisms that remain untapped as pharmacological targets. GIV/Girdin has emerged as a prototypical non-GPCR activator of G proteins that promotes cancer metastasis. Here, we introduce IGGi-11, a first-in-class smallmolecule inhibitor of non-canonical activation of heterotrimeric G-protein signaling. IGGi-11 binding to G-protein α-subunits (Gαi) specifically disrupted their engagement with GIV/Girdin, thereby blocking non-canonical G-protein signaling in tumor cells, and inhibiting pro-invasive traits of metastatic cancer cells in vitro and in mice. In contrast, IGGi-11 did not interfere with canonical G-protein signaling mechanisms triggered by GPCRs. By revealing that small molecules can selectively disable non-canonical mechanisms of G-protein activation dysregulated in disease, these findings warrant the exploration of therapeutic modalities in G-protein signaling that go beyond targeting GPCRs.

Multi-Omics-Based Autophagy-Related Untypical Subtypes in Patients with Cerebral Amyloid Pathology.

Recent multi-omics analyses paved the way for a comprehensive understanding of pathological processes. However, only few studies have explored Alzheimer's disease (AD) despite the possibility of biological subtypes within these patients. For this study, unsupervised classification of four datasets (genetics, miRNA transcriptomics, proteomics, and blood-based biomarkers) using Multi-Omics Factor Analysis+ (MOFA+), along with systems-biological approaches following various downstream analyses are performed. New subgroups within 170 patients with cerebral amyloid pathology (Aß+) are revealed and the features of them are identified based on the top-rated targets constructing multi-omics factors of both whole (M-TPAD) and immune-focused models (M-IPAD). The authors explored the characteristics of subtypes and possible key-drivers for AD pathogenesis. Further in-depth studies showed that these subtypes are associated with longitudinal brain changes and autophagy pathways are main contributors. The significance of autophagy or clustering tendency is validated in peripheral blood mononuclear cells (PBMCs; n = 120 including 30 Aß- and 90 Aß+), induced pluripotent stem cell-derived human brain organoids/microglia (n = 12 including 5 Aß-, 5 Aß+, and CRISPR-Cas9 apolipoprotein isogenic lines), and human brain transcriptome (n = 78). Collectively, this study provides a strategy for precision medicine therapy and drug development for AD using integrative multi-omics analysis and network modelling.

Natural Sulfurs Inhibit LPS-Induced Inflammatory Responses through NF-κB Signaling in CCD-986Sk Skin Fibroblasts.

Lipopolysaccharide (LPS)-induced inflammatory response leads to serious damage, up to and including tumorigenesis. Natural mineral sulfur, non-toxic sulfur (NTS), and methylsulfonylmethane (MSM) have anti-inflammatory activity that may inhibit LPS-induced inflammation. We hypothesized that sulfur compounds could inhibit LPS-induced inflammatory responses in CCD-986Sk skin fibroblasts. We used Western blotting and real-time PCR to analyze molecular signaling in treated and untreated cultures. We also used flow cytometry for cell surface receptor analysis, comet assays to evaluate DNA damage, and ELISA-based cytokine detection. LPS induced TLR4 activation and NF-κB signaling via canonical and protein kinase C (PKC)-dependent pathways, while NTS and MSM downregulated that response. NTS and MSM also inhibited LPS-induced nuclear accumulation and binding of NF-κB to proinflammatory cytokines COX-2, IL-1ß, and IL-6. Finally, the sulfur compounds suppressed LPS-induced ROS accumulation and DNA damage in CCD-986Sk cells. These results suggest that natural sulfur compounds could be used to treat inflammation and may be useful in the development of cosmetics.

Non-toxic sulfur inhibits LPS-induced inflammation by regulating TLR-4 and JAK2/STAT3 through IL-6 signaling.

Janus kinase 2 (JAK2) and STAT3 signaling is considered a major pathway in lipopolysaccharide (LPS)­induced inflammation. Toll­like receptor 4 (TLR­4) is an inflammatory response receptor that activates JAK2 during inflammation. STAT3 is a transcription factor for the pro­inflammatory cytokine IL­6 in inflammation. Sulfur is an essential element in the amino acids and is required for growth and development. Non­toxic sulfur (NTS) can be used in livestock feeds as it lacks toxicity. The present study aimed to inhibit LPS­induced inflammation in C2C12 myoblasts using NTS by regulating TLR­4 and JAK2/STAT3 signaling via the modulation of IL­6. The 3­(4,5­dimethylthiazol­2­yl)­2,5­diphenyltetrazolium bromide assay was conducted to analyze cell viability and reverse transcription polymerase chain reaction and western blotting performed to measure mRNA and protein expression levels. Chromatin immunoprecipitation and enzyme­linked immunosorbent assays were used to determine the binding activity of proteins. The results indicated that NTS demonstrated a protective effect against LPS­induced cell death and inhibited LPS­induced expression of TLR­4, JAK2, STAT3 and IL­6. In addition, NTS inhibited the expression of nuclear phosphorylated­STAT3 and its binding to the IL­6 promoter. Therefore, NTS may be a potential candidate drug for the treatment of inflammation.

5-FU promotes stemness of colorectal cancer via p53-mediated WNT/ß-catenin pathway activation.

5-Fluorouracil (5-FU) remains the first-line treatment for colorectal cancer (CRC). Although 5-FU initially de-bulks the tumor mass, recurrence after chemotherapy is the barrier to effective clinical outcomes for CRC patients. Here, we demonstrate that p53 promotes WNT3 transcription, leading to activation of the WNT/ß-catenin pathway in ApcMin/+/Lgr5EGFP mice, CRC patient-derived tumor organoids (PDTOs) and patient-derived tumor cells (PDCs). Through this regulation, 5-FU induces activation and enrichment of cancer stem cells (CSCs) in the residual tumors, contributing to recurrence after treatment. Combinatorial treatment of a WNT inhibitor and 5-FU effectively suppresses the CSCs and reduces tumor regrowth after discontinuation of treatment. These findings indicate p53 as a critical mediator of 5-FU-induced CSC activation via the WNT/ß-catenin signaling pathway and highlight the significance of combinatorial treatment of WNT inhibitor and 5-FU as a compelling therapeutic strategy to improve the poor outcomes of current 5-FU-based therapies for CRC patients.

Revealing the Activity of Trimeric G-proteins in Live Cells with a Versatile Biosensor Design.

Heterotrimeric G-proteins (Gαßγ) are the main transducers of signals from GPCRs, mediating the action of countless natural stimuli and therapeutic agents. However, there are currently no robust approaches to directly measure the activity of endogenous G-proteins in cells. Here, we describe a suite of optical biosensors that detect endogenous active G-proteins with sub-second resolution in live cells. Using a modular design principle, we developed genetically encoded, unimolecular biosensors for endogenous Gα-GTP and free Gßγ: the two active species of heterotrimeric G-proteins. This design was leveraged to generate biosensors with specificity for different heterotrimeric G-proteins or for other G-proteins, such as Rho GTPases. Versatility was further validated by implementing the biosensors in multiple contexts, from characterizing cancer-associated G-protein mutants to neurotransmitter signaling in primary neurons. Overall, the versatile biosensor design introduced here enables studying the activity of endogenous G-proteins in live cells with high fidelity, temporal resolution, and convenience.

Destabilization of ß-catenin and RAS by targeting the Wnt/ß-catenin pathway as a potential treatment for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a severe and heterogeneous disease that lacks an approved targeted therapy and has a poor clinical outcome to chemotherapy. Although the RAS-ERK signaling axis is rarely mutated in TNBC, ~50% of TNBCs show an increased copy number and overexpression of epidermal growth factor receptor (EGFR). However, EGFR-targeted therapies have offered no improvement in patient survival, underscoring the need to explore downstream targets, including RAS. We found that both ß-catenin and RAS, as well as epidermal growth factor receptor (EGFR), are overexpressed and correlated with one another in tumor tissues of TNBC patients. KYA1797K, an Axin-binding small molecule reducing ß-catenin and RAS expression via degradation and suppressing EGFR expression via transcriptional repression, inhibited the proliferation and the metastatic capability of stable cell lines as well as patient-derived cells (PDCs) established from TNBC patient tissues. KYA1797K also suppressed the stemness of 3D-cultured PDCs and xenografted tumors established by using residual tumors from TNBC patients and those established by the TNBC cell line. Targeting both the Wnt/ß-catenin and RAS-ERK pathways via small molecules simultaneously reducing the levels of ß-catenin, RAS, and EGFR could be a potential therapeutic approach for TNBC.

A mutant KRAS-induced factor REG4 promotes cancer stem cell properties via Wnt/ß-catenin signaling.

Mutant KRAS provides a driving force for enhancement of cancer stem cells (CSCs) characteristics contributing transformation of colorectal cancer (CRC) cells harboring adenomatous polyposis coli (APC) mutations. Here, we identified the factors mediating the promotion of CSCs properties induced by KRAS mutation through microarray analyses of genes specifically induced in CRC spheroids harboring both KRAS and APC mutations. Among them, REG4 was identified as a key factor since CRISPR/Cas9-mediated knockout of REG4 most significantly affected the stem cell characteristics in which CSCs markers were effectively suppressed. We show that REG4 mediates promotion of CSCs properties via Wnt/ß-catenin signaling in various in vitro studies including tumor organoid systems. Furthermore, expression patterns of CSCs markers and REG4 correlated in intestinal tumors from Apcmin/+ /KrasG12D LA2 mice and in CRC patient tissues harboring both KRAS and APC mutations. The role of REG4 in the tumor-initiating capacity accompanied by enhancement of CSCs characteristics was also revealed by NSG mice xenograft system. Collectively, our study highlights the importance of REG4 in promoting CSCs properties induced by KRAS mutation, and provides a new therapeutic strategy for CRC harboring both APC and KRAS mutations.

WDR76 mediates obesity and hepatic steatosis via HRas destabilization.

Ras/MAPK (mitogen active protein kinase) signaling plays contradictory roles in adipocyte differentiation and is tightly regulated during adipogenesis. However, mechanisms regulating adipocyte differentiation involving Ras protein stability regulation are unknown. Here, we show that WD40 repeat protein 76 (WDR76), a novel Ras regulating E3 linker protein, controls 3T3-L1 adipocyte differentiation through HRas stability regulation. The roles of WDR76 in obesity and metabolic regulation were characterized using a high-fat diet (HFD)-induced obesity model using Wdr76-/- mice and liver-specific Wdr76 transgenic mice (Wdr76Li-TG). Wdr76-/- mice are resistant to HFD-induced obesity, insulin resistance and hyperlipidemia with an increment of HRas levels. In contrast, Wdr76Li-TG mice showed increased HFD-induced obesity, insulin resistance with reduced HRas levels. Our findings suggest that WDR76 controls HFD-induced obesity and hepatic steatosis via HRas destabilization. These data provide insights into the links between WDR76, HRas, and obesity.

WDR76 degrades RAS and suppresses cancer stem cell activation in colorectal cancer.

BACKGROUND: Stabilization of RAS is a key event for the hyper-activation of Wnt/ß-catenin signaling and activation of cancer stem cell (CSC) in colorectal cancer (CRC). WD Repeat protein 76 (WDR76) mediates the polyubiquitination-dependent degradation of RAS in hepatocellular carcinoma (HCC). We investigated whether WDR76 destabilizes RAS and acts as a tumor suppressor inhibiting CSC activation in CRC. METHODS: We generated mice with deletion of Wdr76 (Wdr76-/-) and crosses of Wdr76-/- with ApcMin/+ (Wdr76-/-; ApcMin/+) and compared them with wildtype mice (Wdr76+/+) and ApcMin/+ mice (Wdr76+/+; ApcMin/+), respectively. Intestinal crypt lengthening, tumorigenesis and CSC activation were analyzed by histology, immunohistochemistry, and immunoblotting. CRC cell line was engineered to stably express or knockdown WDR76 or control vector and was analyzed after spheroid culture. RESULTS: Wdr76-/- mice, with increased Ras level, displayed crypt elongation and hyper-proliferation. Wdr76-/-; ApcMin/+ mice developed more tumors with bigger sizes than ApcMin/+ mice and their tumors showed increased proliferation and CSC activation with elevated RAS and ß-catenin levels. In CRC cells, overexpression or knockdown of WDR76 decreased or increased the numbers and sizes of CRC spheroids with inhibition or activation of CSC markers, respectively. In human CRC, lower level of WDR76 was associated with poor patient survival. CONCLUSIONS: In analyses of mice with deletion of Wdr76 and CRC spheroids, we found that RAS stability plays important roles in tumorigenesis by affecting proliferation and CSC activation. Our results suggest that destabilization of RAS by WDR76 is a potential strategy for targeting malignant CRC involving CSC activation.

WDR76 is a RAS binding protein that functions as a tumor suppressor via RAS degradation.

Stability regulation of RAS that can affect its activity, in addition to the oncogenic mutations, occurs in human cancer. However, the mechanisms for stability regulation of RAS involved in their activity and its roles in tumorigenesis are poorly explored. Here, we identify WD40-repeat protein 76 (WDR76) as one of the HRAS binding proteins using proteomic analyses of hepatocellular carcinomas (HCC) tissue. WDR76 plays a role as an E3 linker protein and mediates the polyubiquitination-dependent degradation of RAS. WDR76-mediated RAS destabilization results in the inhibition of proliferation, transformation, and invasion of liver cancer cells. WDR76-/- mice are more susceptible to diethylnitrosamine-induced liver carcinogenesis. Liver-specific WDR76 induction destabilizes Ras and markedly reduces tumorigenesis in HRasG12V mouse livers. The clinical relevance of RAS regulation by WDR76 is indicated by the inverse correlation of their expressions in HCC tissues. Our study demonstrates that WDR76 functions as a tumor suppressor via RAS degradation.

Plasma tau/amyloid-ß1-42 ratio predicts brain tau deposition and neurodegeneration in Alzheimer's disease.

One of the hallmarks of Alzheimer's disease is abnormal deposition of tau proteins in the brain. Although plasma tau has been proposed as a potential biomarker for Alzheimer's disease, a direct link to brain deposition of tau is limited. Here, we estimated the amount of in vivo tau deposition in the brain by PET imaging and measured plasma levels of total tau (t-tau), phosphorylated tau (p-tau, T181) and amyloid-ß1-42. We found significant correlations of plasma p-tau, t-tau, p-tau/amyloid-ß1-42, and t-tau/amyloid-ß1-42 with brain tau deposition in cross-sectional and longitudinal manners. In particular, t-tau/amyloid-ß1-42 in plasma was highly predictive of brain tau deposition, exhibiting 80% sensitivity and 91% specificity. Interestingly, the brain regions where plasma t-tau/amyloid-ß1-42 correlated with brain tau were similar to the typical deposition sites of neurofibrillary tangles in Alzheimer's disease. Furthermore, the longitudinal changes in cerebral amyloid deposition, brain glucose metabolism, and hippocampal volume change were also highly associated with plasma t-tau/amyloid-ß1-42. These results indicate that combination of plasma tau and amyloid-ß1-42 levels might be potential biomarkers for predicting brain tau pathology and neurodegeneration.

Rotation tendency of the posteriorly displaced proximal segment after vertical ramus osteotomy.

Intraoral Vertical Ramus Osteotomy (IVRO) is one of the operative techniques used for orthognathic surgery. The aim of this study was to assess the posterior displacement of the proximal segment in patients undergoing IVRO at 1-year follow-up. In total, 52 hemimandibles from 26 patients who underwent IVRO in whom the proximal segment was posteriorly displaced without overlap with the distal segment at immediate post-operation (Imm) (30 cases, experimental group), and 26 patients in whom the proximal segment was not posteriorly displaced with overlap with the distal segment (Imm) (22 cases, control group) under three-dimensional computed tomography (3D CT) were included in the study. To analyze the movement of segments, the positions of the mid condyle point (MCP) and angle of condyle line (Con) were determined and the movement of the ramus angle (posterior edge of proximal segments) was measured at the proximal segment. Regression of the proximal segment in sagittal direction of the MCP was observed in both groups and all directions of the ramus angle in the experimental group, and only sagittal direction in the control group. In conclusion, posterior displacement of the proximal segment after IVRO showed tendency to regress its original position.

A biochemical and genetic discovery pipeline identifies PLCδ4b as a nonreceptor activator of heterotrimeric G-proteins.

Recent evidence has revealed that heterotrimeric G-proteins can be activated by cytoplasmic proteins that share an evolutionarily conserved sequence called the Gα-binding-and-activating (GBA) motif. This mechanism provides an alternative to canonical activation by G-protein-coupled receptors (GPCRs) and plays important roles in cell function, and its dysregulation is linked to diseases such as cancer. Here, we describe a discovery pipeline that uses biochemical and genetic approaches to validate GBA candidates identified by sequence similarity. First, putative GBA motifs discovered in bioinformatics searches were synthesized on peptide arrays and probed in batch for Gαi3 binding. Then, cDNAs encoding proteins with Gαi3-binding sequences were expressed in a genetically-modified yeast strain that reports mammalian G-protein activity in the absence of GPCRs. The resulting GBA motif candidates were characterized by comparison of their biochemical, structural, and signaling properties with those of all previously described GBA motifs in mammals (GIV/Girdin, DAPLE, Calnuc, and NUCB2). We found that the phospholipase Cδ4 (PLCδ4) GBA motif binds G-proteins with high affinity, has guanine nucleotide exchange factor activity in vitro, and activates G-protein signaling in cells, as indicated by bioluminescence resonance energy transfer (BRET)-based biosensors of G-protein activity. Interestingly, the PLCδ4 isoform b (PLCδ4b), which lacks the domains required for PLC activity, bound and activated G-proteins more efficiently than the full-length isoform a, suggesting that PLCδ4b functions as a G-protein regulator rather than as a PLC. In summary, we have identified PLCδ4 as a nonreceptor activator of G-proteins and established an experimental pipeline to discover and characterize GBA motif-containing proteins.

Identification of Ras-degrading small molecules that inhibit the transformation of colorectal cancer cells independent of ß-catenin signaling.

Although the development of drugs that control Ras is an emerging topic in cancer therapy, no clinically applicable drug is currently available. We have previously utilized knowledge of the Wnt/ß-catenin signaling-dependent mechanism of Ras protein stability regulation to identify small molecules that inhibit the proliferation and transformation of various colorectal cancer (CRC) cells via degradation of both ß-catenin and Ras. Due to the absence of Ras degradation in cells expressing a nondegradable mutant form of ß-catenin and the need to determine an alternative mechanism of Ras degradation, we designed a cell-based system to screen compounds that degrade Ras independent of the Wnt/ß-catenin signaling pathway. A cell-based high-content screening (HCS) system that monitors the levels of EGFP-K-RasG12V was established using HCT-116 cells harboring a nondegradable mutant CTNNB1 (ΔS45). Through HCS of a chemical library composed of 10,000 compounds and subsequent characterization of hits, we identified several compounds that degrade Ras without affecting the ß-catenin levels. KY7749, one of the most effective compounds, inhibited the proliferation and transformation of CRC cells, especially KRAS-mutant cells that are resistant to the EGFR monoclonal antibody cetuximab. Small molecules that degrade Ras independent of ß-catenin may able to be used in treatments for cancers caused by aberrant EGFR and Ras.

Giant complex odontoma in the posterior mandible: A case report and literature review.

Odontomas are considered a type of odontogenic hamartoma, and are generally reported not to exceed 3 cm in diameter. Some authors have referred to odontomas with a diameter exceeding 3 cm as giant odontomas. As hamartomas, giant odontomas generally show no signs or symptoms, but if they perforate the mucosa to become exposed in the oral cavity, oral and maxillofacial infections can result. Surgical removal and a histopathological examination may also be required to differentiate them from osteomas, cemento-osseous dysplasia, or mixed odontogenic tumors. This report presents the case of a 28-year-old woman with a giant odontoma in the right mandibular third molar area. Based on a review of the literature published since 2010, only 11 cases of "giant" or "large" odontomas have been reported, most of which were of the complex odontoma type. It was confirmed that they tend to occur in the right posterior mandible.

KY1022, a small molecule destabilizing Ras via targeting the Wnt/ß-catenin pathway, inhibits development of metastatic colorectal cancer.

APC (80-90%) and K-Ras (40-50%) mutations frequently occur in human colorectal cancer (CRC) and these mutations cooperatively accelerate tumorigenesis including metastasis. In addition, both ß-catenin and Ras levels are highly increased in CRC, especially in metastatic CRC (mCRC). Therefore, targeting both the Wnt/ß-catenin and Ras pathways could be an ideal therapeutic approach for treating mCRC patients. In this study, we characterized the roles of KY1022, a small molecule that destabilizes both ß-catenin and Ras via targeting the Wnt/ß-catenin pathway, in inhibiting the cellular events, including EMT, an initial process of metastasis, and apoptosis. As shown by in vitro and in vivo studies using APCMin/+/K-RasG12DLA2 mice, KY1022 effectively suppressed the development of mCRC at an early stage of tumorigenesis. A small molecular approach degrading both ß-catenin and Ras via inhibition of the Wnt/ß-catenin signaling would be an ideal strategy for treatment of mCRC.

Sur8 mediates tumorigenesis and metastasis in colorectal cancer.

Sur8, a scaffold protein of the Ras pathway, interacts with Ras and Raf and modulates the Ras-extracellular signal-regulated kinase (ERK) pathway. Here we show that Sur8 is overexpressed in established human colorectal cancer (CRC) cell lines and CRC patient tissues. Moreover, Sur8 expression is increased during liver metastasis in CRC patients. Sur8 knockdown decreases ERK and Akt activities in CRC cell lines, regardless of their K-Ras, B-Raf or PI3K mutation status. Overexpression or knockdown of Sur8 increases or decreases, respectively, the proliferation or transformation of CRC cell lines. Sur8 knockdown attenuates the migration and invasion of HCT116 CRC cells. Subcutaneous or orthotopic injection of HCT116 cells harboring a doxycycline (Dox)-mediated Sur8 knockdown system in nude mice resulted in decreased tumorigenic potential and inhibited the liver metastatic potential of HCT116 cells. Taken together, our data support the role of Sur8 as a promoter of tumorigenesis and liver metastasis in CRC through its modulation of the Ras-ERK and PI3K-Akt signaling pathways.