Metastatic spread of cancer cells portends a poor prognosis and mortality for lung cancer patients. Hypoxia-inducible factor-1α (HIF-1α) enhances tumor cell motility by activating the epithelial-to-mesenchymal transition (EMT), which is considered a prerequisite for metastasis. Recent studies of microRNA involvement in cancer invasion and metastasis have highlighted the role of such RNAs in tumor development. However, little work has been done to identify tumor suppressor microRNAs that target HIF-1α to down-modulate the EMT and thereby counteract the aggressiveness and metastasis of lung cancer cells. Here, we identified the 3′-untranslated region of HIF-1α mRNA as a target of miR-622 and established that miR-622-mediated down-modulation of HIF-1α correlates with decreased levels of mesenchymal proteins, including Snail, β-catenin, and vimentin. Functional analyses revealed that increased miR-622 expression inhibited lung cancer cell migration and invasion in vitro. miR-622 also inhibited the genesis of metastatic lung nodules as demonstrated in a lung cancer xenograft model in which nude mice were transplanted with A549 cells expressing miR-622. Mechanistic analyses showed that overexpression of EGF decreased the miR-622 level in A549 cells, and this reduction could be rescued by administrating U0126, an inhibitor of ERK. Moreover, miR-622 overexpression mediated by the transcription factor FOXO3a decreased the invasiveness of lung tumor cells by inhibiting HIF-1α via inactivation of ERK signaling in U0126-treated A549 cells. These findings highlight the pivotal role of the FOXO3a/miR-622 axis in inhibiting HIF-1α to interfere with tumor metastasis, and this information may contribute to development of novel therapeutic strategies for treating aggressive lung cancer.
BackgroundHepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. The disease recurrent rate is relatively high resulted in poor 5-year survival in advanced HCC. Cancer stem cells (CSCs) have been considered to be one of the main mechanisms for chemoresistance, metastasis, and recurrent disease. Interferon-induced protein 44-like (IFI44L) gene is a type I interferon-stimulated gene (ISG) and belongs to the IFI44 family. Previous reports indicated antiviral activity against HCV in IFI44L, however, its precise role and function in HCC has not been unveiled.MethodsTo explore the characteristics of hepatic CSCs, we successfully enriched hepatic cancer stem-like cells from three established liver cancer cell lines (Hep3B, HepG2, and PLC lines). Parental Hep3B and HepG2 cells and their sphere cells were treated with doxorubicin for 48 h and cell viability was measured by MTT assay. HCC tissue blocks from 217 patients were sampled for tissue microarray (TMA). Follow-up information and histopathological and clinical data including age, gender, tumor grade, advanced stages, HBV, HCV, tumor number, tumor size, relapse-free survival, and overall survival were obtained from the cancer registry and medical charts. The liver TMA was evaluated for IFI44L expression using immunohistochemical staining and scores.ResultsThese hepatic cancer stem-like cells possess important cancer stemness characteristics including sphere-forming abilities, expressing important HCC cancer stem cell markers, and more chemoresistant. Interestingly, we found that overexpression of IFI44L decreased chemoresistance towards doxorubicin and knockdown of IFI44L restored chemoresistance as well as promoted sphere formation. Furthermore, we found that depletion of IFI44L enhanced migration, invasion, and pulmonary metastasis through activating Met/Src signaling pathway. Clinically, the expression level of IFI44L significantly reduced in HCC tumor tissues. Low expression of IFI44L levels also correlated with larger tumor size, disease relapse, advanced stages, and poor clinical survival in HCC patients.ConclusionTaken together, we first demonstrated that IFI44L is a novel tumor suppressor to affect cancer stemness, metastasis, and drug resistance via regulating Met/Src signaling pathway in HCC and can be serve as an important prognostic marker.Electronic supplementary materialThe online version of this article (10.1186/s12885-018-4529-9) contains supplementary material, which is available to authorized users.
BackgroundCD133 (prominin-1) is widely believed to be a cancer stem cell marker in various solid tumor types, and CD133 has been correlated with tumor-initiating capacity. Recently, the nuclear location of CD133 expression in tumors has been discussed, but hepatocellular carcinoma (HCC) has not been included in these discussions. The goal of this study was to investigate the location of CD133 expression in HCC and this location’s potential value as a prognostic indicator of survival in patients with HCC.MethodsWe enrolled 119 cancerous tissues and pair-matched adjacent normal liver tissue from HCC patients. These tissues were obtained immediately after operation, and tissue microarrays were subsequently constructed. The expression of CD133 was measured by immunohistochemistry (IHC), and the correlations between this expression and clinical characteristics and prognosis was estimated using statistical analysis.ResultsThe results showed that the CD133 protein expression levels of HCC in both the cytoplasm and nucleus were significantly higher than adjacent normal liver tissue. Kaplan–Meier survival and Cox regression analyses revealed that high CD133 expression in the cytoplasm was an independent predictor of poor prognosis for the overall survival (OS) and relapse-free survival (RFS) rates of HCC patients (P = 0.028 and P = 0.046, respectively). Surprisingly, high nuclear CD133 expression of HCC was an independent predictor of the good prognosis of the OS and RFS rates of HCC patients (P = 0.023 and P = 0.012, respectively).ConclusionsThe clinical evidence that revealed cytoplasmic CD133 expression was correlated with poor prognosis, while nuclear CD133 expression was significantly correlated with favorable prognosis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-017-3460-9) contains supplementary material, which is available to authorized users.
BackgroundCancer stem cells (CSCs) are believed to promote the malignant transformation of breast cancer via multiple signaling pathways, including the Wnt/β-catenin pathway. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) has been identified as a CSC-associated Wnt-regulated target gene, but its clinical significance in the context of breast cancer remains elusive. Therefore, the purpose of this study was to investigate the clinical significance of the LGR5-β-catenin axis in breast cancer.MethodsBreast cancer tissue blocks from 126 patients were used to construct a tissue microarray (TMA). Histopathological and clinical data including age; tumor size; estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) level; tumor grade; lymph node (LN) status; and survival were obtained from the cancer registry database and patients’ medical records. Tissue on the breast TMA was scored for LGR5 and β-catenin expression using semi-quantitative immunohistochemical (IHC) staining. We also analyzed LGR5 expression in cellular datasets available through ONCOMINE, a web-based cancer microarray database.ResultsImmunohistochemical staining revealed that 58 tumors (46%) exhibited high LGR5 expression, whereas 56 tumors (47%) displayed high β-catenin expression. High levels of LGR5 expression were significantly associated with tumor size (p = 0.002), LN metastasis status (p = 0.044), and triple-negative breast cancer (p = 0.029), consistent with our findings from the ONCOMINE database. In addition, we also found that β-catenin -expressing breast cancers were positive correlated with HER2 overexpression. Finally, with respect to clinical outcomes, patients with high levels of LGR5-β-catenin axis expression exhibited poorer relapse-free survival (RFS) compared to patients with low levels of LGR5-β-catenin axis expression (p = 0.027).ConclusionLGR5 overexpression was significantly associated with high T stage and LN metastasis status. High LGR5 expression was also associated with reduced RFS, indicating that LGR5 may represent a promising prognostic marker for breast cancer patients.
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