Carla Vetrugno

CCL20 induces migration and proliferation on breast epithelial cells

The communication between the tumor cells and the surrounding cells helps drive the process of tumor progression. Since the microenvironment of breast cancer includes CCL20 chemokine, the purpose of this study was to determine whether CCL20 modulates the physiology of healthy breast epithelial cells in areas adjacent to the tumor. Therefore, primary cultures of mammary cells taken from normal peritumoral areas were used. We assessed that breast cells expressed CCR6 CCL20 receptor. Using molecular (siRNA) and pharmacological (inhibitors) techniques, we found multiple signaling kinases to be activated by CCR6 and involved in CCL20‐induced breast cell proliferation and migration. The binding of 10 ng/ml CCL20 to CCR6 induced cell migration whilst higher concentrations (from 15 to 25 ng/ml) led to cell proliferation. CCL20 controlled cell migration and MMP‐9 expression by PKC‐alpha that activated Src, which caused the activation of downstream Akt, JNK, and NF‐kB pathways. Furthermore, higher CCL20 concentrations increased cycE and decreased p27Kip expression ending in enhanced cell proliferation. Cell proliferation occurred through PKC‐epsilon activation that transactivated EGFR and ERK1/2/MAPK pathway. Although activated by different CCL20 concentrations, these pathways function in parallel and crosstalk to some extent, inasmuch as Akt activation was responsible for ERK1/2 nuclear translocation and enhanced the transcription of of c‐fos and c‐myc, involved in cell proliferation. In summary, tumor cells exchange signals with the surrounding healthy cells modifying the extracellular matrix through enzyme secretion; thus, CCL20 might be a factor involved in the ontogeny of breast carcinoma. J. Cell. Physiol. 228: 1873–1883, 2013.

Sublethal concentrations of the platinum(II) complex [Pt(O,O′‐acac)(γ‐acac)(DMS)] alter the motility and induce anoikis in MCF‐7 cells

Background and purpose:  We showed previously that a new Pt(II) complex ([Pt(O,O′‐acac)(γ‐acac)(DMS)]) exerted high and fast apoptotic processes in MCF‐7 cells. The objective of this study was to investigate the hypothesis that [Pt(O,O′‐acac)(γ‐acac)(DMS)] is also able to exert anoikis and alter the migration ability of MCF‐7 cells, and to show some of the signalling events leading to these alterations.

A new platinum(II) compound anticancer drug candidate with selective cytotoxicity for breast cancer cells

[Pt(O,O′-acac)(γ-acac)(DMS)] (PtAcD) is able to induce apoptosis in various human cancer cells, including the cisplatin-resistant human breast carcinoma MCF-7 cells. Here, to confirm that PtAcD has the potentiality for therapeutic intervention, we studied its effects in primary cultured epithelial breast cells obtained from cancers and also from the corresponding histologically proven non-malignant tissue adjacent to the tumor. We demonstrated that PtAcD (1) is more cytotoxic in cancer than in normal breast cells; (2) activated NAD(P)H oxidase, leading to PKC-ζ and PKC-α tanslocations; (3) activated antiapoptotic pathways based on the PKC-α, ERK1/2 and Akt kinases; (4) activated PKC-ζ and, only in cancer cell PKC-δ, responsible for the sustained phosphorylation of p38 and JNK1/2, kinases both of which are involved in the mitochondrial apoptotic process. Moreover, crosstalk between ERK/Akt and JNK/p38 pathways affected cell death and survival in PtAcD-treated breast cell. In conclusion, this study adds and extends data that highlight the pharmacological potential of PtAcD as an anti breast cancer drug.

Anti‐apoptotic effects of protein kinase C‐δ and c‐fos in cisplatin‐treated thyroid cells

Background and purpose:  We showed previously that cisplatin inititates a signalling pathway mediated by PKC‐δ/extracellular signal‐regulated kinase (ERK), important for maintaining viability in PC Cl3 thyroid cells. The studies described herein examined whether c‐fos was associated with cisplatin resistance and the signalling link between c‐fos and PKC‐δ/ERK.

Antitumor activity of [Pt( O,O’ -acac)( γ -acac)(DMS)] in mouse xenograft model of breast cancer

The higher and selective cytotoxicity of [Pt(O,O′-acac)(γ-acac)(DMS)] toward cancer cell in both immortalized cell lines and in breast cancer cells in primary cultures, stimulated a pre-clinical study so as to evaluate its therapeutic potential in vivo. The efficacy of [Pt(O,O′-acac)(γ-acac)(DMS)] was assessed using a xenograft model of breast cancer developed by injection of MCF-7 cells in the flank of BALB/c nude mice. Treatment of solid tumor-bearing mice with [Pt(O,O′-acac)(γ-acac)(DMS)] induced up to 50% reduction of tumor mass compared with an average 10% inhibition recorded in cisplatin-treated animals. Thus, chemotherapy with [Pt(O,O′-acac)(γ-acac)(DMS)] was much more effective than cisplatin. We also demonstrated enhanced in vivo pharmacokinetics, biodistribution and tolerability of [Pt(O,O′-acac)(γ-acac)(DMS)] when compared with cisplatin administered in Wistar rats. Pharmacokinetics studies with [Pt(O,O′-acac)(γ-acac)(DMS)] revealed prolonged Pt persistence in systemic blood circulation and decreased nefrotoxicity and hepatotoxicity, major target sites of cisplatin toxicity. Overall, [Pt(O,O′-acac)(γ-acac)(DMS)] turned out to be extremely promising in terms of greater in vivo anticancer activity, reduced nephrotoxicity and acute toxicity compared with cisplatin.

Functions of epidermal growth factor receptor in cisplatin response of thyroid cells

Epidermal growth factor receptor (EGFR) signal transduction pathway has been reported to play a vital role in the biologic progression of several tumours and as targets for therapeutic intervention. We have investigated the role of EGFR in the thyroid PC Cl3 cells response to the chemo-therapeutic agent cisplatin. It was found that cisplatin provoked (1) the activation (phosphorylation) and internalization of EGFR, (2) the phosphorylation of mitogen-activated protein kinase (MAPK)/p38, (3) the activation of PKC-epsilon, (4) the enhancement of matrix metalloproteinase-2 (MMP-2) expression and activity, (5) the generation of reactive oxygen species (ROS) and (6) the activation of the apoptotic intrinsic pathway. Inhibition or down regulation of EGFR reduced (1) the phosphorylation of MAPK/p38, (2) the cisplatin-provoked activation of PKC-epsilon, and (3) the activation of caspase-7 and PARP cleavage and the overall cells sensitivity to cisplatin. PKC-epsilon inhibition achieved by siRNA blocked MAPK/p38 activation and significantly increased the cell resistance to cisplatin. Finally, when the cisplatin-induced ROS generation was blocked by using NAD(P)H oxidase inhibitors, a decrease in cisplatin-induced MMP-2 enhancement, MAPK/p38 and EGFR activation, and caspase-7 proteolysis occurred. In conclusion, these findings supported a model in which cisplatin provokes an oxidant-induced MMP-2-dependent EGFR transactivation responsible for the induction of cell apoptosis, a process ascribable to the intracellular signalling of PKC-epsilon and MAPK/p38.

Paracrine CCL20 loop induces epithelial‐mesenchymal transition in breast epithelial cells

We previously found that CCL20 induced primarily cultured healthy breast cell proliferation and migration. The objective of this study was to investigate the hypothesis that CCL20 modulated the epithelial‐mesenchymal transition (EMT) of primarily cultured healthy breast epithelial cells and the angiogenesis in areas adjacent to the tumor. Key results showed that CCL20 (a) down‐regulated E‐cadherin and ZO‐1; (b) up‐regulated N‐cadherin, vimentin, and Snail expressions; (c) increased mRNA and secretion of VEGF and (d) increased angiogenic micro vessel sprouting. Thus, the signal transduction pathways evoked by CCL20 were investigated. We showed that NF‐kB p65 down‐regulation (by small interfering RNA, siRNA) reversed CCL20‐induced Snail and blocked the up‐regulation of vimentin and N‐cadherin mRNAs. Furthermore, PI3K/AKT inhibition (by LY294002) completely blocked CCL20‐induced Snail and NF‐kB activation. Inhibition of JNK1/2 (by SP60125) or PKC‐α (by siRNA) or src (by PP1) blocked NF‐kB activation and Snail expression suggesting that these kinases are all upstream of NF‐kB/Snail. Inhibition of mTOR (by rapamycin) abolished the effects of CCL20 on N‐cadherin and vimentin protein synthesis. Furthermore, siRNA of PKC‐δ inhibited the phosphorylation of CCL20‐induced mTOR and S6, increased vimentin and N‐cadherin expressions and, finally, blocked the CCL20 induced‐EMT. CCL20 increased mRNA and secretion of VEGF by healthy breast cells by using PKC‐α, src, Akt, NF‐kB, and Snail signalling. In summary, tumor cells signal to the surrounding healthy cells through CCL20 inducing the modulation of the expression of molecules involved in EMT and promoting angiogenesis directly and indirectly through the secretion of VEGF, a major contributor to angiogenesis.

Different apoptotic effects of [Pt(O,O′-acac)(γ-acac)(DMS)] and cisplatin on normal and cancerous human epithelial breast cells in primary culture

The aim of this study was to determine whether [platinum (Pt)(O,O′‐acetylacetonate (acac))(γ‐acac)(dimethylsulphide (DMS))] is differentially cytotoxic in normal and cancer cells, and to measure comparative levels of cytotoxicity compared with cisplatin in the same cells.

PKC-δ/PKC-α activity balance regulates the lethal effects of cisplatin

Cisplatin is commonly employed in therapy of mesothelioma but its efficacy is limited and the mechanisms by which induces its effects are not clearly understood. PKCs can regulate cisplatin sensitivity. PKCs effects on cellular sensitivity/resistance depend on the pattern of active PKC isozymes as well as on cellular context. The present study was undertaken to determine if specific PKC isoforms regulate cisplatin-induced apoptosis in the human mesothelioma ZL55 cells. Cells were treated with cisplatin at various concentrations and for different incubation periods. Cytotoxicity assays and Western blottings of various proteins involved in apoptosis and survival were then performed. Exposure of ZL55 cells to cisplatin at concentrations ranging from 1 to 200 μM resulted in a dose-dependent inhibition of cell survival and the activation of the mitochondrial apoptotic pathway. Cisplatin activated full-length PKC-δ and generated a PKC-δ fragment. PKC-δ inhibition (by PKC-δ-siRNA) decreased ZL55 cell apoptosis. Full-length PKC-δ translocated to the nucleus and activated caspase-3 expression, whereas PKC-δ fragment preferentially localized to mitochondria. Cisplatin also provoked the generation of reactive oxygen species (ROS) by NADPH oxidase. ROS increment was responsible for the PKC-α activation that provoked EGFR transactivation and consequential phosphorylation of ERK1/2. The inhibition of this pathway at various level (PKC-α, EGFR or ERK1/2) increased cisplatin-induced cytotoxicity. The results suggest that PKC-δ is an essential part of the apoptotic program in mesothelioma cells, whereas PKC-α mediates a pro-survival response to cisplatin.

[Pt(O,O’-acac)(γ-acac)(DMS)] Alters SH-SY5Y Cell Migration and Invasion by the Inhibition of Na+/H+ Exchanger Isoform 1 Occurring through a PKC-ε/ERK/mTOR Pathway

We previously showed that [Pt(O,O’-acac)(γ-acac)(DMS)] ([Pt(acac)2(DMS)]) exerted substantial cytotoxic effects in SH-SY5Y neuroblastoma cells, and decreased metalloproteases (MMPs) production and cells migration in MCF-7 breast cancer cells. The ubiquitously distributed sodium-hydrogen antiporter 1 (NHE1) is involved in motility and invasion of many solid tumours. The present study focuses on the effects of [Pt(acac)2(DMS)] in SH-SY5Y cell migration and also on the possibility that NHE1 may be involved in such effect. After sublethal [Pt(acac)2(DMS)] treatment cell migration was examined by wounding assay and cell invasion by transwell assay. NHE1 activity was measured in BCECF-loaded SH-SY5Y as the rate of Na+-dependent intracellular pH recovery in response to an acute acid pulse. Gelatin zymography for MMP-2/9 activities, Western blottings of MMPs, MAPKs, mTOR, S6 and PKCs and small interfering RNAs to PKC-ε/-δ mRNA were performed. Sublethal concentrations of [Pt(acac)2(DMS)] decreases NHE1 activity, inhibites cell migration and invasion and decreases expression and activity of MMP-2 and -9. [Pt(acac)2(DMS)] administered to SH-SY5Y cells provokes the increment of ROS, generated by NADPH oxidase, responsible for the PKC-ε and PKC-δ activation. Whilst PKC-δ activates p38/MAPK, responsible for the inhibition of MMP-2 and -9 secretion, PKC-ε activates a pathway made of ERK1/2, mTOR and S6K responsible for the inhibition of NHE1 activity and cell migration. In conclusion, we have shown a drastic impairment in tumour cell metastatization in response to inhibition of NHE1 and MMPs activities by [Pt(acac)2(DMS)] occurring through a novel mechanism mediated by PKC-δ/-ε activation.