Chemotherapy resistance in acute lymphoblastic leukemia requires hERG1 channels and is overcome by hERG1 blockers.

Bone marrow mesenchymal cells (MSCs) can protect leukemic cells from chemotherapy, thus increasing their survival rate. We studied the potential molecular mechanisms underlying this effect in acute lymphoblastic leukemia (ALL) cells. Coculture of ALL cells with MSCs induced on the lymphoblast plasma membrane the expression of a signaling complex formed by hERG1 (human ether-à-go-go-related gene 1) channels, the ß(1)-integrin subunit, and the chemokine receptor CXC chemokine receptor-4. The assembly of such a protein complex activated both the extracellular signal-related kinase 1/2 (ERK1/2) and the phosphoinositide 3-kinase (PI3K)/Akt prosurvival signaling pathways. At the same time, ALL cells became markedly resistant to chemotherapy-induced apoptosis. hERG1 channel function appeared to be important for both the initiation of prosurvival signals and the development of drug resistance, because specific channel blockers decreased the protective effect of MSCs. NOD/SCID mice engrafted with ALL cells and treated with channel blockers showed reduced leukemic infiltration and had higher survival rates. Moreover, hERG1 blockade enhanced the therapeutic effect produced by corticosteroids. Our findings provide a rationale for clinical testing of hERG1 blockers in the context of antileukemic therapy for patients with ALL.

ETV4 promotes late development of prostatic intraepithelial neoplasia and cell proliferation through direct and p53-mediated downregulation of p21.

BACKGROUND: ETV4 is one of the ETS proteins overexpressed in prostate cancer (PC) as a result of recurrent chromosomal translocations. In human prostate cell lines, ETV4 promotes migration, invasion, and proliferation; however, its role in PC has been unclear. In this study, we have explored the effects of ETV4 expression in the prostate in a novel transgenic mouse model. METHODS: We have created a mouse model with prostate-specific expression of ETV4 (ETV4 mice). By histochemical and molecular analysis, we have investigated in these engineered mice the expression of p21, p27, and p53. The implications of our in vivo findings have been further investigated in human cells lines by chromatin-immunoprecipitation (ChIP) and luciferase assays. RESULTS: ETV4 mice, from two independent transgenic lines, have increased cell proliferation in their prostate and two-thirds of them, by the age of 10 months, developed mouse prostatic intraepithelial neoplasia (mPIN). In these mice, cdkn1a and its p21 protein product were reduced compared to controls; p27 protein was also reduced. By ChIP assay in human prostate cell lines, we show that ETV4 binds to a specific site (-704/-696 bp upstream of the transcription start) in the CDKN1A promoter that was proven, by luciferase assay, to be functionally competent. ETV4 further controls CDKN1A expression by downregulating p53 protein: this reduction of p53 was confirmed in vivo in ETV4 mice. CONCLUSIONS: ETV4 overexpression results in the development of mPIN but not in progression to cancer. ETV4 increases prostate cell proliferation through multiple mechanisms, including downregulation of CDKN1A and its p21 protein product: this in turn is mediated through direct binding of ETV4 to the CDKN1A promoter and through the ETV4-mediated decrease of p53. This multi-faceted role of ETV4 in prostate cancer makes it a potential target for novel therapeutic approaches that could be explored in this ETV4 transgenic model.

Characterization of hERG1 channel role in mouse colorectal carcinogenesis.

The human ether-à-go-go-related gene (hERG)1 K(+) channel is upregulated in human colorectal cancer cells and primary samples. In this study, we examined the role of hERG1 in colorectal carcinogenesis using two mouse models: adenomatous polyposis coli (Apc(min/+) ) and azoxymethane (AOM)-treated mice. Colonic polyps of Apc(min/+) mice overexpressed mERG1 and their formation was reverted by the hERG1 blocker E4031. AOM was applied to either hERG1-transgenic (TG) mice, which overexpress hERG1 in the mucosa of the large intestine, or wild-type mice. A significant increase of both mucin-depleted foci and polyps in the colon of hERG1-TG mice was detected. Both the intestine of TG mice and colonic polyps of Apc(min/+) showed an upregulation of phospho-Protein Kinase B (pAkt)/vascular endothelial growth factor (VEGF-A) and an increased angiogenesis, which were reverted by treatment with E4031. On the whole, this article assigns a relevant role to hERG1 in the process of in vivo colorectal carcinogenesis.

Over-Expression of the LH Receptor Increases Distant Metastases in an Endometrial Cancer Mouse Model.

OBJECTIVE: The aim of the present study was to define the role of luteinizing hormone receptor (LH-R) expression in endometrial cancer (EC), using preclinical mouse models, to further transfer these data to the clinical setting. MATERIALS AND METHODS: The role of LH-R over-expression was studied using EC cells (Hec1A, e.g., cells with low endogenous LH-R expression) transfected with the LH-R (Hec1A-LH-R). In vitro cell proliferation was measured through the WST-1 assay, whereas cell invasion was measured trough the matrigel assay. The effects of LH-R over-expression in vivo were analyzed in an appropriately developed preclinical mouse model of EC, which mimicked postmenopausal conditions. The model consisted in an orthotopic xenograft of Hec1A cells into immunodeficient mice treated daily with recombinant LH, to assure high levels of LH. RESULTS: In vitro data indicated that LH-R over-expression increased Hec1A invasiveness. In vivo results showed that tumors arising from Hec1A-LH-R cells injection displayed a higher local invasion and a higher number of distant metastases, mainly in the lung, compared to tumors obtained from the injection of Hec1A cells. LH withdrawal strongly inhibited local and distant metastatic spread of tumors, especially those arising from Hec1A-LH-R cells. CONCLUSION: The over-expression of the LH-R increases the ability of EC cells to undergo local invasion and metastatic spread. This occurs in the presence of high LH serum concentrations.

hERG1 channels modulate integrin signaling to trigger angiogenesis and tumor progression in colorectal cancer.

Angiogenesis is a potential target for cancer therapy. We identified a novel signaling pathway that sustains angiogenesis and progression in colorectal cancer (CRC). This pathway is triggered by ß1 integrin-mediated adhesion and leads to VEGF-A secretion. The effect is modulated by the human ether-à-go-go related gene 1 (hERG1) K(+) channel. hERG1 recruits and activates PI3K and Akt. This in turn increases the Hypoxia Inducible Factor (HIF)-dependent transcription of VEGF-A and other tumour progression genes. This signaling pathway has novel features in that the integrin- and hERG1-dependent activation of HIF (i) is triggered in normoxia, especially after CRC cells have experienced a hypoxic stage, (ii) involves NF-kB and (iii) is counteracted by an active p53. Blocking hERG1 switches this pathway off also in vivo, by inhibiting cell growth, angiogenesis and metastatic spread. This suggests that non-cardiotoxic anti-hERG1 drugs might be a fruitful therapeutic strategy to prevent the failure of anti-VEGF therapy.

A highly soluble matrix metalloproteinase-9 inhibitor for potential treatment of dry eye syndrome.

Dry eye syndrome (DES) or keratoconjunctivitis sicca is an eye disease caused by the chronic lack of lubrication and moisture of the eye. The pathogenesis of DES involves the over-expression and over-activity of corneal Matrix Metalloproteinase 9 (MMP-9). We propose herein a new, non-symptomatic approach for the treatment of DES based on the inhibition of MMP-9 by a new highly soluble molecule, designed as PES_103 that has been shown to inhibit MMP-9 both in vitro and in vivo. The efficacy of PES_103 in vivo and the potential benefits of this treatment in restoring tear production were studied in this work using an animal model of reduced lacrimation. PES_103 did not show any significant corneal toxicity.