Tumor suppressor ING4 inhibits estrogen receptor activity in breast cancer cells

Cxcl10 chemokine induces migration of ING4-deficient breast cancer cells via a novel crosstalk mechanism between the Cxcr3 and Egfr receptors

The chemokine Cxcl10 has been associated with poor prognosis in breast cancer, but the mechanism is not well understood. Our previous study have shown that CXCL10 was repressed by the ING4 tumor suppressor, suggesting a potential inverse functional relationship. We thus investigated a role for Cxcl10 in the context of ING4 deficiencies in breast cancer. We first analyzed public gene expression datasets and found that patients with CXCL10-high/ING4-low expressing tumors had significantly reduced disease-free survival in breast cancer. In vitro, Cxcl10 induced migration of ING4-deleted breast cancer cells, but not of ING4-intact cells. Using inhibitors, we found that Cxcl10-induced migration of ING4-deleted cells required Cxcr3, Egfr, and the Gβγ subunits downstream of Cxcr3, but not Gαi. Immunofluorescent imaging showed that Cxcl10 induced early transient colocalization between Cxcr3 and Egfr in both ING4-intact and ING4-deleted cells, which recurred only in ING4-deleted cells. A peptide agent that binds to the internal juxtamembrane domain of Egfr inhibited Cxcr3/Egfr colocalization and cell migration. Taken together, these results presented a novel mechanism of Cxcl10 that elicits migration of ING4-deleted cells, in part by inducing a physical or proximal association between Cxcr3 and Egfr and signaling downstream via Gβγ. These results further indicated that ING4 plays a critical role in the regulation of Cxcl10 signaling that enables breast cancer progression.

Nuclear ING3 Expression Is Correlated With a Good Prognosis of Breast Cancer

The inhibitor of growth (ING) family was discovered as the type II tumor suppressors, which regulated the proliferation, apoptosis, differentiation, angiogenesis, metastasis, and invasion of tumor cells through multiple pathways. ING3, a new member of ING family, has been reported to be downregulated in several types of tumors. However, few studies on ING3 in breast cancer have been reported. In this study, we investigated the expression of ING3 and determined its prognostic value in breast cancer. The immunohistochemistry was performed to evaluate the expression of ING3 in tissue microarrays (TMA) including breast cancer tissues (n=211) and normal breast tissues (n=50). In normal breast tissues, ING3 protein was detected in both the cytoplasm and nucleus. In breast cancer tissues, ING3 protein was principally detected in the cytoplasm. Compared with normal breast tissues, the expression of ING3 in nucleus was remarkably reduced in breast cancer tissues. The downregulated ING3 in nucleus was significantly correlated with clinicopathological characteristics including histological grade, lymph node metastasis, and the status of ER and PR. In HER2 positive-type and triple-negative breast cancer (TNBC) patients, it had the lower rate of nuclear ING3 with high expression than that in luminal-type. Moreover, Kaplan-Meier curves demonstrated that the reduced expression of ING3 in nucleus was correlated with a poorer 5-DFS and 5-OS of breast cancer patients. Importantly, multivariate Cox regression analysis suggested that the reduced expression of ING3 in nucleus was an independent prognostic factor in breast cancer. Our study comprehensively described the expression of ING3 in breast cancer for the first time and proved that it was an independent prognostic predictor of breast cancer, as well as a new idea for study of breast cancer.

miR-650 promotes non-small cell lung cancer cell proliferation and invasion by targeting ING4 through Wnt-1/β-catenin pathway

Non-small cell lung cancer (NSCLC) is the most frequent cancer worldwide with a poor 5-year survival. miR-650 acts as an oncogene and regulates tumor progress in various cancers. Molecular mechanisms of miR-650 in NSCLC cell proliferation and invasion was studied. The mRNA levels of miR-650 and special genes were calculated using RT-qPCR. MTT and transwell assays were applied to measure the proliferative and invasive ability. Kaplan-Meier method was used to assess the survival of NSCLC patients. miR-650 was upregulated in NSCLC and upregulation of miR-650 was associated with a poor overall survival of NSCLC, while the results of ING4 demonstrated the opposite results. miR-650 promoted proliferation and invasion through Wnt-1/β-catenin pathway by targeting inhibitor of growth 4 (ING4) in A549 cells. ING4 was a direct target gene of miR-650 and the expression of ING4 was mediated by exogenous altering the expression of miR-650. Remarkably, alterations of ING4 expression eliminated the functions of miR-650 on the proliferation and metastasis of NSCLC. miR-650 enhanced A549 cell proliferation and invasion through Wnt-1/β-catenin pathway by directly targeting the 3'-UTR of ING4 mRNA. The newly identified miR-650/ING4 axis provides a novel insight into the pathogenesis of NSCLC.

Essential oil from Cymbopogon flexuosus as the potential inhibitor for HSP90

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The essential oil of Cymbopogon flexuosus or lemongrass oil (LO) is reported.

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Essential oil of C. flexuosus significantly suppresses the HSP90 gene expression.

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Increased expression of HSP90 gene by citral and geraniol in HEK-293 cells.

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Inhibition of HSP90-ATPase acitivity by the essential oil of C. flexuosus.

The essential oil of Cymbopogon flexuosus or lemongrass oil (LO) is reported to have antibacterial, antifungal and anticancerous effects. HSP90 is one of the major chaperones responsible for the proper folding of cancer proteins. In this paper we show that the essential oil of C. flexuosus significantly suppresses the HSP90 gene expression. The cytotoxicity of the compounds was tested by MTT assay and the gene expression studies were carried out using HEK-293 and MCF-7 cells. Also we tested the efficacy of the major component of this essential oil viz. citral and geraniol in inhibiting the HSP90 expression. The oil was found to be more cytotoxic to MCF-7 cells with different IC₅₀ values for the oil (69.33 μg/mL), citral (140.7 μg/mL) and geraniol (117 μg/mL). The fold change of expression was calculated by RT-qPCR using ΔΔCt (2^{^−ΔΔCt}) method and it was 0.1 and 0.03 in MCF-7 cells at 80 μg/mL and 160 μg/mL of LO. Western blot results showed suppression of HSP90 protein expression and HSP90 – ATPase activity inhibition was also observed using LO. This study shows the anticancer mechanism exhibited by the essential oil of C. flexuosus is by the inhibition of the important chaperone protein HSP90.