SCEL regulates switches between pro-survival and apoptosis of the TNF-α/TNFR1/NF-κB/c-FLIP axis to control lung colonization of triple negative breast cancer.

BACKGROUND: Patients with metastatic triple-negative breast cancer (mTNBC) have a higher probability of developing visceral metastasis within 5 years after the initial diagnosis. Therefore, a deeper understanding of the progression and spread of mTNBC is urgently needed. METHODS: The isobaric tag for relative and absolute quantitation (iTRAQ)-based LC-MS/MS proteomic approach was applied to identify novel membrane-associated proteins in the lung-tropic metastatic cells. Public domain datasets were used to assess the clinical relevance of the candidate proteins. Cell-based and mouse models were used for biochemical and functional characterization of the protein molecule Sciellin (SCEL) identified by iTRAQ to elucidate its role and underlying mechanism in promoting lung colonization of TNBC cells. RESULTS: The iTRAQ-based LC-MS/MS proteomic approach identified a membrane-associated protein SCEL that was overexpressed in the lung-tropic metastatic cells, and its high expression was significantly correlated with the late-stage TNBC and the shorter survival of the patients. Downregulation of SCEL expression significantly impaired the 3D colony-forming ability but not the migration and invasion ability of the lung colonization (LC) cells. Knockdown of SCEL reduced TNF-α-induced activation of the NF-κB/c-FLIP pro-survival and Akt/Erk1/2 growth signaling pathways in the LC cells. Specifically, knockdown of SCEL expression switched TNF-α-mediated cell survival to the caspase 3-dependent apoptosis. Conversely, ectopic expression of SCEL promoted TNF-α-induced activation of NF-κB/c-FLIP pro-survival and Akt/Erk1/2 pro-growth signaling pathway. The result of co-immunoprecipitation (Co-IP) and GST pull-down assay showed that SCEL could interact with TNFR1 to promote its protein stability. The xenograft mouse model experiments revealed that knockdown of SCEL resulted in increase of caspase-3 activity, and decrease of ki67 and TNFR1 expression as well as increase of tumor-associated macrophages in the metastatic lung lesions. Clinically, SCEL expression was found to be positively correlated with TNFR1 in TNBC tissues. Lastly, we showed that blocking TNF-α-mediated cell survival signaling by adalimumab effectively suppressed the lung colonization of the SCEL-positive, but not the SCEL-downregulated LC cells in the tail-vein injection model. CONCLUSIONS: Our findings indicate that SCEL plays an essential role in the metastatic lung colonization of TNBC by promoting the TNF-α/TNFR1/NF-κB/c-FLIP survival and Akt/Erk1/2 proliferation signaling. Thus, SCEL may serve as a biomarker for adalimumab treatment of TNBC patients.

Dual antibody-aided mesoporous nanoreactor for H2O2 self-supplying chemodynamic therapy and checkpoint blockade immunotherapy in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) represents a formidable challenge due to the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, rendering it unresponsive to conventional hormonal and targeted therapies. This study introduces the development of mesoporous nanoreactors (NRs), specifically mPDA@CuO2 NRs, as acid-triggered agents capable of self-supplying H2O2 for chemodynamic therapy (CDT). To enhance therapeutic efficacy, these NRs were further modified with immune checkpoint antagonists, specifically anti-PD-L1 and anti-CD24 antibodies, resulting in the formation of dual antibody-aided mesoporous nanoreactors (dAbPD-L1/CD24-mPDA@CuO2 NRs). These NRs were designed to combine CDT and checkpoint blockade immunotherapy (CBIT) for precise targeting of 4T1 TNBC cells. Remarkably, dAbPD-L1/CD24-mPDA@CuO2 NRs exhibited tumor-targeted CDT triggered by H2O2 and successfully activated immune cells including T cells and macrophages. This integrated approach led to a remarkable inhibition of tumor growth by leveraging the collaborative effects of the therapies. The findings of this study introduce a novel and promising strategy for the integrative and collaborative treatment of refractory cancers, providing valuable insights into addressing the challenges posed by aggressive breast cancer, particularly TNBC.

MAP7D3, a novel prognostic marker for triple-negative breast cancer, drives cell invasiveness and cancer-initiating cell properties to promote metastatic progression.

BACKGROUND: Patients with triple-negative breast cancer (TNBC) tend to develop visceral metastasis within five years, making them the most challenging BC patients to treat. The MAP7 protein family is a group of microtubule-binding proteins with a well-known role in microtubule-related cell migration, but its role in metastasis-related properties of TNBC remains unclear. METHODS: qRT-PCR and western blot were used to validate mRNA and protein expression of the MAP7 family in the isogenic pairs of TNBC cell lines with low and high metastasis potential. Functional characterization of MAP7D3 was carried out using cell-based and mouse models. The clinical association between MAP7D3 and TNBC was established using datasets in the public domain. RESULTS: MAP7D3 expression was consistently upregulated in the metastatic subline IV2 and 468-LN at both mRNA and protein levels. Knockdown of MAP7D3 inhibited the 3D colony-forming ability, cell migration, and invasion ability of IV2 and 468-LN, indicating its significant contribution to the metastasis phenotypes. Mechanistically, inhibition of MAP7D3 could significantly increase the sensitivity of metastatic TNBC cells to docetaxel and gemcitabine treatment by reducing the expression of proteins related to breast cancer-initiating cells (BCICs) and drug resistance, as well as suppressing the activity of Rac1. The animal study showed that the depletion of MAP7D3 drastically reduced TNBC tumor growth and impaired the metastatic capability of TNBC cells. Elevated expression of MAP7D3 was found in the metastatic lymph nodes and was significantly associated with advanced stage and higher grade TNBC. Moreover, MAP7D3 expression was significantly correlated with the TNBC population, and its high expression was significantly associated with lymph node metastasis and poor survival outcomes of patients with TNBC. CONCLUSION: Our study indicates that targeting MAP7D3 could be a promising therapeutic strategy for addressing the progression of TNBC, and MAP7D3 may serve as a novel predictive biomarker for the survival outcomes of triple-negative breast cancer.

Effect of Polarized Training on Cardiorespiratory Fitness of Untrained Healthy Young Adults: A Randomized Control Trial with Equal Training Impulse.

To explore the effects of 8-week polarized training (POL), high-intensity interval training (HIIT), and threshold training (THR) interventions on the cardiorespiratory fitness (CRF) of untrained healthy young adults. This study recruited 36 young adults and randomly assigned them to POL, HIIT, THR, or control (CG) groups to undergo an 8-week training intervention. The training impulse applied to all three intervention groups was identical. The training intensity was divided into Zone 1, 2, and 3 (Z1, Z2 and Z3) on the basis of the ventilatory thresholds (VT). The weekly training intensity distribution for POL was 75% of Z1 and 25% of Z3; HIIT was 100% of Z3 and THR was 50% of Z1 and 50% of Z2. Each group underwent Bruce protocol testing and supramaximal testing before, during, and after the intervention; relevant CRF parameters were assessed. 8 weeks of POL and HIIT significantly increased VT2 (p < 0.05); 8 weeks of POL, HIIT, THR and significantly increased VO2max and TTE (p < 0.05). The effect size of POL in relation to VO2max and TTE improvements was greater than that of HIIT and THR (g = 2.67 vs. 1.26 and 1.49; g = 2.75 vs. 2.05 and 1.60). Aerobic training models with different intensity distributions have different time effects on improving CRF. Relative to HIIT and THR, POL improved more variables of CRF. Therefore, POL is a feasible aerobic training method for improving CRF.

Cure the Incurable? Recent Breakthroughs in Immune Checkpoint Blockade for Hepatocellular Carcinoma.

HCC usually arises from a chronic inflammation background, driven by several factors including fatty liver, HBV/HCV viral infection and metabolic syndrome. Systemic treatment for advanced HCC remains disappointing due to its strong resistance to chemotherapy and even to tyrosine kinase inhibitors (TKIs). Recently, the use of ICI therapy has revolutionized the systemic treatment of advanced HCC. For the first time, clinical trials testing ICIs, anti-CTLA-4 and anti-PD1/PDL1 reported a survival benefit in patients with sorafenib resistance. However, it took four more years to find the right combination regimen to use ICI in combination with the anti-angiogenic agent bevacizumab to substantially prolong overall survival (OS) of patients with advanced HCC after sorafenib. This review provides a comprehensive history of ICI therapy in HCC, up-to-date information on the latest ICI clinical trials, and discusses the recent development of novel ICIs that would potentially lead to a new checkpoint blockade therapy for advanced HCC.

LOC550643, a Long Non-coding RNA, Acts as Novel Oncogene in Regulating Breast Cancer Growth and Metastasis.

Metastatic disease is responsible for over 90% of death in patients with breast cancer. Therefore, identifying the molecular mechanisms that regulate metastasis and developing useful therapies are crucial tasks. Long non-coding RNAs (lncRNAs), which are non-coding transcripts with >200 nucleotides, have recently been identified as critical molecules for monitoring cancer progression. This study examined the novel lncRNAs involved in the regulation of tumor progression in breast cancer. This study identified 73 metastasis-related lncRNA candidates from comparison of paired isogenic high and low human metastatic breast cancer cell lines, and their expression levels were verified in clinical tumor samples by using The Cancer Genome Atlas. Among the cell lines, a novel lncRNA, LOC550643, was highly expressed in breast cancer cells. Furthermore, the high expression of LOC550643 was significantly correlated with the poor prognosis of breast cancer patients, especially those with triple-negative breast cancer. Knockdown of LOC550643 inhibited cell proliferation of breast cancer cells by blocking cell cycle progression at S phase. LOC550643 promoted important in vitro metastatic traits such as cell migration and invasion. Furthermore, LOC550643 could inhibit miR-125b-2-3p expression to promote breast cancer cell growth and invasiveness. In addition, by using a xenograft mouse model, we demonstrated that depletion of LOC550643 suppressed the lung metastatic potential of breast cancer cells. Overall, our study shows that LOC550643 plays an important role in breast cancer cell metastasis and growth, and LOC550643 could be a potential diagnosis biomarker and therapeutic target for breast cancer.

Identification of the Novel Oncogenic Role of SAAL1 and Its Therapeutic Potential in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide, affecting over 700,000 people per year. The treatment effect in advanced HCC is still disappointing and prognosis of advanced HCC remains poor. Hence, to find more effective therapeutic targets to improve the treatment outcome of HCC is of urgent need. In this study, we reported the novel oncogenic function of SAAL1 (serum amyloid A-like 1) in HCC, which previously is considered as an inflammation-related gene. We found that SAAL1 was significantly upregulated in HCC tumor tissues when compared to the adjacent normal tissues and high expression of SAAL1 correlated with shorter overall survival in The Cancer Genome Atlas (TCGA) HCC database. Functionally, we showed that the depletion of SAAL1 significantly reduced cell proliferation, 3D colony formation, and migration/invasion abilities of HCC cancer cells. Furthermore, suppression of SAAL1 impaired the HGF/Met-driven Akt/mTOR phosphorylation cascade and increased the chemosensitivity of HCC cells to sorafenib and foretinib treatment. Our data indicated that SAAL1 plays an important role in HCC via mediating oncogenic HGF/Met-driven Akt/mTOR signaling and could serve as an independent prognostic marker, as well as a promising therapeutic target for HCC patients.

Dysregulation of cystathionine γ-lyase promotes prostate cancer progression and metastasis.

Hydrogen sulfide (H2 S), an endogenous signaling gaseous molecule, is involved in various physiological activities, including vessel relaxation, regulation of cellular bioenergetics, inflammation, and angiogenesis. By using xenograft orthotopic implantation of prostate cancer PC3 cells and subsequently comparing bone metastatic with primary tumor-derived cancer cells, we find that H2 S-producing enzyme cystathionine γ-lyase (CTH) is upregulated in bone-metastatic PC3 cells. Clinical data further reveal that the expression of CTH is elevated in late-stage prostate cancer patients, and higher CTH expression correlates with poor survival from The Cancer Genome Atlas (TCGA) prostate cancer RNA-seq datasets. CTH promotes NF-κB nuclear translocation through H2 S-mediated sulfhydration on cysteine-38 of the NF-κB p65 subunit, resulting in increased IL-1ß expression and H2 S-induced cell invasion. Knockdown of CTH in PC3 cells results in the suppression of tumor growth and distant metastasis, while overexpression of CTH in DU145 cells promotes primary tumor growth and lymph node metastasis in the orthotopic implanted xenograft mouse model. Together, our findings provide evidence that CTH generated H2 S promotes prostate cancer progression and metastasis through IL-1ß/NF-κB signaling pathways.

Cancer-Derived VEGF-C Increases Chemokine Production in Lymphatic Endothelial Cells to Promote CXCR2-Dependent Cancer Invasion and MDSC Recruitment.

Breast cancer-derived vascular endothelial growth factor-C (VEGF-C) has been shown to enhance lymphangiogenesis in lymph nodes to accelerate cancer metastasis. However, the remodeling of lymph node microenvironments by VEGF-C remains elusive. By in vivo selection, we established a subline (named as "LC") with strong lymphatic tropism and high VEGF-C expression from the human MDA-MB-231 breast cancer cell line. Co-culture with LC cells or treatment with LC-conditioned medium upregulated the expression of CXC chemokines in lymphatic endothelial cells (LECs), which could be inhibited by pre-incubation with VEGF-C-neutralizing antibodies and VEGFR3 inhibitors. The chemokines produced by LECs enhanced recruitment of myeloid-derived suppressor cells (MDSCs) to tumor-draining and distant lymph nodes in tumor-bearing mice. Treatment with a CXCR2 inhibitor after tumor cell inoculation dramatically decreased the number of MDSCs in lymph nodes, suggesting the importance of the chemokine/CXCR2 signaling axis in MDSC recruitment. In addition, LEC-released chemokines also stimulated the expression of serum amyloid A1 (SAA1) in cancer cells, enhancing their lymphatic invasion by increasing VE-cadherin phosphorylation, junction disruption, and vascular permeability of LECs. Clinical sample validation confirmed that SAA1 expression was associated with increased lymph node metastasis. Collectively, we reveal a novel mechanism by which cancer cell-derived VEGF-C remodels lymphovascular microenvironments by regulating chemokine production in LECs to promote cancer invasion and MDSC recruitment. Our results also suggest that inhibition of CXCR2 is effective in treating lymphatic metastasis.

A novel miR-365-3p/EHF/keratin 16 axis promotes oral squamous cell carcinoma metastasis, cancer stemness and drug resistance via enhancing ß5-integrin/c-met signaling pathway.

BACKGROUND: Targeting the c-Met signaling pathway has become a therapeutic strategy in multiple types of cancer. We unveiled a novel c-Met regulating mechanism that could be applied as a modality for oral squamous cell carcinoma (OSCC) therapy. METHODS: Upregulation of keratin 16 (KRT16) was found by comparing isogenic pairs of low and high invasive human OSCC lines via microarray analysis. OSCC cells with ectopic expression or silencing of KRT16 were used to scrutinize functional roles and associated molecular mechanisms. RESULTS: We observed that high KRT16 expression significantly correlated with poorer pathological differentiation, advanced stages, increased lymph nodes metastasis, and decreased survival rate from several Taiwanese OSCC patient cohorts. We further revealed that miR-365-3p could target ETS homologous factor (EHF), a KRT16 transcription factor, to decrease migration, invasion, metastasis and chemoresistance in OSCC cells via inhibition of KRT16. Under confocal microscopic examination, c-Met was found possibly partially associates with KRT16 through ß5-integrin. Colocalization of these three proteins may facilitate c-Met and ß5-integrin-mediated signaling in OSCC cells. Depletion of KRT16 led to increased protein degradation of ß5-integrin and c-Met through a lysosomal pathway leading to inhibition of their downstream Src/STAT3/FAK/ERK signaling in OSCC cells. Knockdown of KRT16 enhanced chemosensitivity of OSCC towards 5-fluorouracil (5-FU). Various combination of c-Met inhibitor (foretinib), protein tyrosine kinase inhibitor (genistein), ß5-integrin antibody, and 5-FU markedly augmented cytotoxic effects in OSCC cells as well as tumor killing effects in vitro and in vivo. CONCLUSIONS: Our data indicate that targeting a novel miR-365-3p/EHF/KRT16/ß5-integrin/c-Met signaling pathway could improve treatment efficacy in OSCC.

Identification of the Novel Role of CD24 as an Oncogenesis Regulator and Therapeutic Target for Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, with unfavorable prognosis and 5-year survival. The purpose of this study was to investigate the underlying mechanisms involved in TNBC progression. We determined that CD24 expression was elevated in highly lung and lymph node metastatic TNBC cells. CD24 depletion inhibited primary tumor growth and lymph node and lung metastasis and reduced the number of blood and lymphatic vessels in the tumor microenvironment. CD24 knockdown impaired EGFR/Met-mediated signaling and reduced lymphangiogenesis- and angiogenesis-related molecules, including vascular endothelial growth factors A and C, by promoting EGFR and Met protein instability via the lysosomal degradation pathway. CD24 monoclonal antibody treatment reduced lung metastasis and prolonged the survival in a lung metastasis mouse model. Clinical analyses revealed that the CD24 high/MET high "double-positive" signature identified a subset of TNBC patients with worst outcomes. We conclude that CD24 could be a therapeutic target by itself and in combination with the Met expression could be a good prognostic biomarker for TNBC patients.

Wild-type p53 upregulates an early onset breast cancer-associated gene GAS7 to suppress metastasis via GAS7-CYFIP1-mediated signaling pathway.

The early onset breast cancer patients (age ≤ 40) often display higher incidence of axillary lymph node metastasis, and poorer five-year survival than the late-onset patients. To identify the genes and molecules associated with poor prognosis of early onset breast cancer, we examined gene expression profiles from paired breast normal/tumor tissues, and coupled with Gene Ontology and public data base analysis. Our data showed that the expression of GAS7b gene was lower in the early onset breast cancer patients as compared to the elder patients. We found that GAS7 was associated with CYFIP1 and WAVE2 complex to suppress breast cancer metastasis via blocking CYFIP1 and Rac1 protein interaction, actin polymerization, and ß1-integrin/FAK/Src signaling. We further demonstrated that p53 directly regulated GAS7 gene expression, which was inversely correlated with p53 mutations in breast cancer specimens. Our study uncover a novel regulatory mechanism of p53 in early onset breast cancer progression through GAS7-CYFIP1-mediated signaling pathways.

Isocitrate dehydrogenase 1-snail axis dysfunction significantly correlates with breast cancer prognosis and regulates cell invasion ability.

BACKGROUND: The isocitrate dehydrogenase (IDH) gene family expresses key functional metabolic enzymes in the Krebs cycle and mediates the epigenetic reprogramming, which serves as an important biomarker of breast cancer. However, the expression levels of the IDH protein and their biological function in human breast cancer remain largely unknown. METHODS: In this study, the clinical impact of IDH1 expression on the progression and prognosis of breast cancer was evaluated using immunohistochemistry assay (IHC) of the corresponding tumor-adjacent normal, ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC) tissues from 309 patients with breast ductal carcinoma. The relationship between microRNA (miRNA) and IDH1 were examined by a bioinformatics approach, western blot and reporter assay. The biological functions of IDH1 were examined in breast cancer cells with IDH1 knockdown, including proliferation, migration and invasion. RESULTS: The present findings revealed that the mRNA and protein expression levels of IDH1 were both significantly lower in breast cancer tissues than in adjacent normal tissues. A low expression level of IDH1 in breast cancer significantly correlated with advanced stage (p = 0.012), lymph node metastasis (p = 0.018), and poor disease-specific survival (DSS) (adjusted hazard ratio (AHR), 1.57, 95% confidence interval (CI), 1.08-2.30; p = 0.02). Furthermore, oncogenic miR-32 and miR-92b were identified to suppress IDH1 expression, leading to the inhibition of cell migration and invasion. We further explored whether reduced expression of IDH1 significantly increases snail expression by activating HIFα (hypoxia-inducible factor-1 alpha) and NFκB (nuclear factor kappa B) signaling. Multivariate Cox regression analysis revealed that the combination of low IDH1 and high snail expression could be an independent risk factor for shorter DSS (AHR, 2.34; 95% CI, 1.32-4.16; p = 0.004) and shorter disease-free survival (AHR, 2.50; 95% CI, 1.39-4.50; p = 0.002) in patients with breast cancer. CONCLUSION: Our findings revealed that a IDH1low/Snailhigh molecular signature could serve as an independent biomarker for poor prognosis in breast cancer.

Transketolase Regulates the Metabolic Switch to Control Breast Cancer Cell Metastasis via the α-Ketoglutarate Signaling Pathway.

Although metabolic reprogramming is recognized as a hallmark of tumorigenesis and progression, little is known about metabolic enzymes and oncometabolites that regulate breast cancer metastasis, and very few metabolic molecules have been identified as potential therapeutic targets. In this study, the transketolase (TKT) expression correlated with tumor size in the 4T1/BALB/c syngeneic model. In addition, TKT expression was higher in lymph node metastases compared with primary tumor or normal tissues of patients, and high TKT levels were associated with poor survival. Depletion of TKT or addition of alpha-ketoglutarate (αKG) enhanced the levels of tumor suppressors succinate dehydrogenase and fumarate hydratase (FH), decreasing oncometabolites succinate and fumarate, and further stabilizing HIF prolyl hydroxylase 2 (PHD2) and decreasing HIF1α, ultimately suppressing breast cancer metastasis. Reduced TKT or addition of αKG mediated a dynamic switch of glucose metabolism from glycolysis to oxidative phosphorylation. Various combinations of the TKT inhibitor oxythiamine, docetaxel, and doxorubicin enhanced cell death in triple-negative breast cancer (TNBC) cells. Furthermore, oxythiamine treatment led to increased levels of αKG in TNBC cells. Together, our study has identified a novel TKT-mediated αKG signaling pathway that regulates breast cancer oncogenesis and can be exploited as a modality for improving therapy.Significance: These findings uncover the clinical significance of TKT in breast cancer progression and metastasis and demonstrate effective therapy by inhibiting TKT or by adding αKG. Cancer Res; 78(11); 2799-812. ©2018 AACR.

The expression of a tumor suppressor gene JDP2 and its prognostic value in hepatocellular carcinoma patients.

The c-Jun dimerization protein 2 (JDP2) belongs to the activator protein-1 (AP-1) family and functions as a repressor of the AP-1 complex by dimerizing with other c-Jun proteins. Thus, JDP2 plays an important role in the repression of AP-1-driven biological processes, such as differentiation and proliferation. Recent studies have suggested that JDP2 may function as a tumor suppressor through its suppressive action against the AP-1 complex, which is known to drive oncogenic signals in several human malignancies. In this study, we used immunohistochemistry to examine the JDP2 expression in 211 cases of hepatocellular carcinoma (HCC) and analyzed the potential link of JDP2 expression to the clinicopathological features of HCC patients. Clinical parameter analysis showed that high expression of JDP2 was significantly correlated with smaller tumor size (P=.002) and early stage HCC (P=.039). Moreover, Kaplan-Meier survival analysis showed that high expression of JDP2 was significantly associated with better survival in HCC patients (P=.006). Taken together, our results showed that JDP2 may serve as a tumor suppressor in HCC and could therefore serve as a good prognostic marker for patients with HCC.

Regulation of cancer metastasis by microRNAs.

MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs that have been found highly conserved among species. MiRNAs are able to negatively regulate gene expression through base pairing of 3' UTRs of their target genes. Therefore, miRNAs have been shown to play an important role in regulating various cellular activities. Over the past decade, substantial evidences have been obtained to show that miRNAs are aberrantly expressed in human malignancies and could act as "OncomiRs" or "Tumor suppressor miRs". In recent years, increasing number of studies have demonstrated the involvement of miRNAs in cancer metastasis. Many studies have shown that microRNAs could directly target genes playing a central role in epithelia-mesenchymal-transition (EMT), a cellular transformation process that allows cancer cells to acquire motility and invasiveness. EMT is considered an essential step driving the early phase of cancer metastasis. This review will summarize the recent findings and characterization of miRNAs that are involved in the regulation of EMT, migration, invasion and metastasis of cancer cells. Lastly, we will discuss potential use of miRNAs as diagnostic and prognostic biomarkers as well as therapeutic targets for cancer.

miRNA-491-5p and GIT1 serve as modulators and biomarkers for oral squamous cell carcinoma invasion and metastasis.

MicroRNAs offer tools to identify and treat invasive cancers. Using highly invasive isogenic oral squamous cell carcinoma (OSCC) cells, established using in vitro and in vivo selection protocols from poorly invasive parental cell populations, we used microarray expression analysis to identify a relative and specific decrease in miR-491-5p in invasive cells. Lower expression of miR-491-5p correlated with poor overall survival of patients with OSCCs. miR-491-5p overexpression in invasive OSCC cells suppressed their migratory behavior in vitro and lung metastatic behavior in vivo. We defined the G-protein-coupled receptor kinase-interacting protein 1 (GIT1)-as a direct target gene for miR-491-5p control. GIT1 overexpression was sufficient to rescue miR-491-5p-mediated inhibition of migration/invasion and lung metastasis. Conversely, GIT1 silencing phenocopied the ability of miR-491-5p to inhibit migration/invasion and metastasis of OSCC cells. Mechanistic investigations indicated that miR-491-5p overexpression or GIT1 attenuation reduced focal adhesions, with a concurrent decrease in steady-state levels of paxillin, phospho-paxillin, phospho-FAK, EGF/EGFR-mediated extracellular signal-regulated kinase (ERK1/2) activation, and MMP2/9 levels and activities. In clinical specimens of OSCCs, GIT1 levels were elevated relative to paired normal tissues and were correlated with lymph node metastasis, with expression levels of miR-491-5p and GIT1 correlated inversely in OSCCs, where they informed tumor grade. Together, our findings identify a functional axis for OSCC invasion that suggests miR-491-5p and GIT1 as biomarkers for prognosis in this cancer.

Upregulation of SOX9 in lung adenocarcinoma and its involvement in the regulation of cell growth and tumorigenicity.

PURPOSE: SOX9 is an important transcription factor required for development and has been implicated in several types of cancer. However, SOX9 has never been linked to lung cancer to date. Here, we show that SOX9 expression is upregulated in lung adenocarcinoma and show how it is associated with cancer cell growth. EXPERIMENTAL DESIGN: Data mining with five microarray data sets containing 490 clinical samples, quantitative reverse transcription-PCR validation assay in 57 independent samples, and immunohistochemistry assay with tissue microarrays containing 170 lung tissue cores were used to profile SOX9 mRNA and protein expression. Short interference RNA suppression of SOX9 in cell lines was used to scrutinize functional role(s) of SOX9 and associated molecular mechanisms. RESULTS: SOX9 mRNA and protein were consistently overexpressed in the majority of lung adenocarcinoma. Knockdown of SOX9 in lung adenocarcinoma cell lines resulted in marked decrease of adhesive and anchorage-independent growth in concordance with the upregulation of p21 (CDKN1A) and downregulation of CDK4. In agreement with higher SOX9 expression level in lung adenocarcinoma, the p21 mRNA level was significantly lower in tumors than that in normal tissues, whereas the opposite was true for CDK4, supporting the notion that SOX9 negatively and positively regulated p21 and CDK4, respectively. Finally, whereas SOX9-knockdown cells showed significantly attenuated tumorigenicity in mice, SOX9 transfectants consistently showed markedly stronger tumorigenicity. CONCLUSIONS: Our data suggest that SOX9 is a new hallmark of lung adenocarcinoma, in which SOX9 might contribute to gain of tumor growth potential, possibly acting through affecting the expression of cell cycle regulators p21 and CDK4.

Proteomics of the radioresistant phenotype in head-and-neck cancer: Gp96 as a novel prediction marker and sensitizing target for radiotherapy.

PURPOSE: Radiotherapy is an integral part of the treatment modality for head-neck cancer (HNC), but in some cases the disease is radioresistant. We designed this study to identify molecules that may be involved in this resistance. METHODS AND MATERIALS: Two radioresistant sublines were established by fractionated irradiation of the HNC cell lines, to determine differentially proteins between parental and radioresistant cells. Proteomic analysis and reverse-transcription polymerase chain reaction were used to identify and confirm the differential proteins. The siRNA knockdown experiments were applied to examine cellular functions of a radioresistant gene, with investigation of the alterations in colonogenic survival, cell cycle status, and reactive oxygen species levels. Xenografted mouse tumors were studied to validate the results. RESULTS: IN all, 64 proteins were identified as being potentially associated with radioresistance, which are involved in several cellular pathways, including regulation of stimulus response, cell apoptosis, and glycolysis. Six genes were confirmed to be differentially expressed in both radioresistant sublines, with Gp96, Grp78, HSP60, Rab40B, and GDF-15 upregulated, and annexin V downregulated. Gp96 was further investigated for its functions in response to radiation. Gp96-siRNA transfectants displayed a radiation-induced growth delay, reduction in colonogenic survival, increased cellular reactive oxygen species levels, and increased proportion of the cells in the G2/M phase. Xenograft mice administered Gp96-siRNA showed significantly enhanced growth suppression in comparison with radiation treatment alone (p = 0.009). CONCLUSIONS: We identified 64 proteins and verified 6 genes that are potentially involved in the radioresistant phenotype. We further demonstrated that Gp96 knockdown enhances radiosensitivity both in cells and in vivo, which may lead to a better prognosis of HNC treatment.