miR-125b induces cellular senescence in malignant melanoma.

BACKGROUND: Micro RNAs (miRs) have emerged as key regulators during oncogenesis. They have been found to regulate cell proliferation, differentiation, and apoptosis. Mir-125b has been identified as an oncomir in various forms of tumours, but we have previously proposed that miR-125b is a suppressor of lymph node metastasis in cutaneous malignant melanoma. Our goal was therefore to further examine this theory. METHODS: We used in-situ-hybridization to visualise miR-125b expression in primary tumours and in lymph node metastasis. Then using a miRVector plasmid containing a miR-125b-1 insert we transfected melanoma cell line Mel-Juso and then investigated the effect of the presence of a stable overexpression of miR-125b on growth by western blotting, flow cytometry and ß-galactosidase staining. The tumourogenicity of the transfected cells was tested using a murine model and the tumours were further examined with in-situ-hybridization. RESULTS: In primary human tumours and in lymph node metastases increased expression of miR-125b was found in single, large tumour cells with abundant cytoplasm. A stable overexpression of miR-125b in human melanoma cell line Mel-Juso resulted in a G0/G1 cell cycle block and emergence of large cells expressing senescence markers: senescence-associated beta-galactosidase, p21, p27 and p53. Mel-Juso cells overexpressing miR-125b were tumourigenic in mice, but the tumours exhibited higher level of cell senescence and decreased expression of proliferation markers, cyclin D1 and Ki67 than the control tumours. CONCLUSIONS: Our results confirm the theory that miR-125b functions as a tumour supressor in cutaneous malignant melanoma by regulating cellular senescence, which is one of the central mechanisms protecting against the development and progression of malignant melanoma.

Optimization of pig models for translation of subcutaneous pharmacokinetics of therapeutic proteins: Liraglutide, insulin aspart and insulin detemir.

Prediction of human pharmacokinetics (PK) from data obtained in animal studies is essential in drug development. Here, we present a thorough examination of how to achieve good pharmacokinetic data from the pig model for translational purposes by using single-species allometric scaling for selected therapeutic proteins: liraglutide, insulin aspart and insulin detemir. The predictions were based on non-compartmental analysis of intravenous and subcutaneous PK data obtained from two injection regions (neck, thigh) in two pig breeds, domestic pig and Göttingen Minipig, that were compared with PK parameters reported in humans. The effects of pig breed, injection site and injection depth (insulin aspart only) on the PK of these proteins were also assessed. Results show that the prediction error for human PK was within two-fold for most PK parameters in both pig breeds. Furthermore, pig breed significantly influenced the plasma half-life and mean absorption time (MAT), both being longer in Göttingen Minipigs compared to domestic pigs (P <0.01). In both breeds, thigh vs neck dosing was associated with a higher dose-normalized maximum plasma concentration and area under the curve as well as shorter MAT and plasma half-life (P <0.01). Finally, more superficial injections resulted in faster absorption, higher Cmax/dose and bioavailability of insulin aspart (P <0.05, 3.0 vs 5.0 mm injection depth). In conclusion, pig breed and injection region affected the PK of liraglutide, insulin aspart and insulin detemir and reliable predictions of human PK were demonstrated when applying single-species allometric scaling with the pig as a pre-clinical animal model.

Molecular Engineering of Efficacious Mono-Valent Ultra-Long Acting Two-Chain Insulin-Fc Conjugates.

Here, we describe molecular engineering of monovalent ultra-long acting two-chain insulin-Fc conjugates. Insulin-Fc conjugates were synthesized using trifunctional linkers with one amino reactive group for reaction with a lysine residue of insulin and two thiol reactive groups used for re-bridging of a disulfide bond within the Fc molecule. The ultra-long pharmacokinetic profile of the insulin-Fc conjugates was the result of concertedly slowing insulin receptor-mediated clearance by (1) introduction of amino acid substitutions that lowered the insulin receptor affinity and (2) conjugating insulin to the Fc element. Fc conjugation leads to recycling by the neonatal Fc receptor and increase in the molecular size, both contributing to the ultra-long pharmacokinetic and pharmacodynamic profiles.

Engineering of Orally Available, Ultralong-Acting Insulin Analogues: Discovery of OI338 and OI320.

Recently, the first basal oral insulin (OI338) was shown to provide similar treatment outcomes to insulin glargine in a phase 2a clinical trial. Here, we report the engineering of a novel class of basal oral insulin analogues of which OI338, 10, in this publication, was successfully tested in the phase 2a clinical trial. We found that the introduction of two insulin substitutions, A14E and B25H, was needed to provide increased stability toward proteolysis. Ultralong pharmacokinetic profiles were obtained by attaching an albumin-binding side chain derived from octadecanedioic (C18) or icosanedioic acid (C20) to the lysine in position B29. Crucial for obtaining the ultralong PK profile was also a significant reduction of insulin receptor affinity. Oral bioavailability in dogs indicated that C18-based analogues were superior to C20-based analogues. These studies led to the identification of the two clinical candidates OI338 and OI320 (10 and 24, respectively).

Molecular Engineering of Insulin Icodec, the First Acylated Insulin Analog for Once-Weekly Administration in Humans.

Here, we describe the molecular engineering of insulin icodec to achieve a plasma half-life of 196 h in humans, suitable for once-weekly subcutaneously administration. Insulin icodec is based on re-engineering of the ultra-long oral basal insulin OI338 with a plasma half-life of 70 h in humans. This systematic re-engineering was accomplished by (1) further increasing the albumin binding by changing the fatty diacid from a 1,18-octadecanedioic acid (C18) to a 1,20-icosanedioic acid (C20) and (2) further reducing the insulin receptor affinity by the B16Tyr → His substitution. Insulin icodec was selected by screening for long intravenous plasma half-life in dogs while ensuring glucose-lowering potency following subcutaneous administration in rats. The ensuing structure-activity relationship resulted in insulin icodec. In phase-2 clinical trial, once-weekly insulin icodec provided safe and efficacious glycemic control comparable to once-daily insulin glargine in type 2 diabetes patients. The structure-activity relationship study leading to insulin icodec is presented here.

Peptides derived from specific interaction sites of the fibroblast growth factor 2-FGF receptor complexes induce receptor activation and signaling.

Basic fibroblast growth factor (FGF2, bFGF) is the most extensively studied member of the FGF family and is involved in neurogenesis, differentiation, neuroprotection, and synaptic plasticity in the CNS. FGF2 executes its pleiotropic biologic actions by binding, dimerizing, and activating FGF receptors (FGFRs). The present study reports the physiologic impact of various FGF2-FGFR1 contact sites employing three different synthetic peptides, termed canofins, designed based on structural analysis of the interactions between FGF2 and FGFR1. Canofins mimic the cognate ligand interaction with the receptor and preserve the neuritogenic and neuroprotective properties of FGF2. Canofins were shown by surface plasmon resonance analysis to bind to FGFR1 and promote receptor activation. However, FGF2-induced receptor phosphorylation was inhibited by canofins, indicating that canofins are partial FGFR agonists. Furthermore, canofins were demonstrated to induce neuronal differentiation determined by neurite outgrowth from cerebellar granule neurons, and this effect was dependent on FGFR activation. Additionally, canofins acted as neuroprotectants, promoting survival of cerebellar granule neurons induced to undergo apoptosis. Our results suggest that canofins mirror the effect of specific interaction sites in FGF2 for FGFR. Thus, canofins are valuable pharmacological tools to study the functional roles of specific molecular interactions of FGF2 with FGFR.

A neutralizing antibody against DKK1 does not reduce plaque formation in classical murine models of atherosclerosis: Is the therapeutic potential lost in translation?

BACKGROUND AND AIMS: Clinical interventions targeting nonlipid risk factors are needed given the high residual risk of atherothrombotic events despite effective control of dyslipidemia. Dickkopf-1 (DKK1) plays a lipid-independent role in vascular pathophysiology but its involvement in atherosclerosis development and its therapeutic attractiveness remain to be established. METHODS: Patient data, in vitro studies and pharmacological intervention in murine models of atherosclerosis were utilized. RESULTS: In patients' material (n = 127 late stage plaque specimens and n = 10 control vessels), DKK1 mRNA was found to be higher in atherosclerotic plaques versus control arteries. DKK1 protein was detected in the luminal intimal area and in the necrotic core of plaques. DKK1 was released from isolated primary human platelets (~12 - 21-fold) and endothelial cells (~1.4-2.5-fold) upon stimulation with different pathophysiological stimuli. In ApoE-/- and Ldlr-/- mice, plasma DKK1 concentrations were similar to those observed in humans, whereas DKK1 expression in different atheroprone arterial segments was very low/absent. Chronic treatment with a neutralizing DKK1 antibody effectively reduced plasma concentrations, however, plaque lesion area was not reduced in ApoE-/- and Ldlr-/- mice fed a western diet for 14 and 16 weeks. Anti-DKK1 treatment increased bone volume and bone mineral content. CONCLUSIONS: Functional inhibition of DKK1 with an antibody does not alter atherosclerosis progression in classical murine models. This may reflect the absence of DKK1 expression in plaques and more advanced animal disease models could be needed to evaluate the role and therapeutic attractiveness of DKK1 in late stage complications such as plaque destabilization, calcification, rupture and thrombosis.

Chemotherapeutic treatment is associated with Notch1 induction in cutaneous T-cell lymphoma.

The Notch pathway is important for survival of cutaneous T-cell lymphoma (CTCL) cells. We investigated the effect of chemotherapy (doxorubicin, etoposide, and gemcitabine) and radiation modalities on Notch signaling in CTCL cell lines. Chemotherapy induced Notch1 expression at the mRNA and protein level in MyLa2000 and Hut78. Upregulation of well-established Notch targets supported the functional activity of Notch1. Transfection of Notch1 siRNA into MyLa2000 cells was not able to suppress the effects of chemotherapy on Notch1 activation significantly. Notch1 knockdown in combination with doxorubicin, etoposide, or gemcitabine compared to chemotherapy alone decreased cell viability by 12, 20, and 26%, respectively (p < 0.05). Additionally, X-rays (in MyLa2000 but not SeAx) and psoralen plus UVA (PUVA) (in MyLa2000, Hut78, and SeAx) increased the expression of Notch1 family members. Our results indicate that CTCL cells activate the Notch pathway in vitro in response to chemotherapy and radiation modalities as a possible protective mechanism.

Ellipticine induces apoptosis in T-cell lymphoma via oxidative DNA damage.

The tumor suppressor p53 is often mutated in human cancers. Restoring its antitumor activity has been shown to be a promising therapeutic approach for cancer treatment. Here we analyzed the activity and mechanism of a p53 reactivator, ellipticine, in a cellular model of cutaneous T-cell lymphoma (CTCL), a disease that is progressive, chemoresistant and refractory to treatment. We tested the effect of ellipticine in three cell lines with different p53 status: MyLa2000 (p53(wt/wt)), SeAx ((G245S)p53) and Hut-78 ((R196Stop)p53). Ellipticine caused apoptosis in MyLa2000 and SeAx and restored the transcriptional activity of (G245S)p53 in SeAx. However, p53 siRNA knockdown experiments revealed that p53 was not required for ellipticine-induced apoptosis in CTCL. The lipophilic antioxidant α-tocopherol inhibited ellipticine-dependent apoptosis and we linked the apoptotic response to the oxidative DNA damage. Our results provide evidence that ellipticine-induced apoptosis is exerted through DNA damage and does not require p53 activation in T-cell lymphoma.

MicroRNA expression analysis and Multiplex ligation-dependent probe amplification in metastatic and non-metastatic uveal melanoma.

PURPOSE: To determine the association of microRNA expression and chromosomal changes with metastasis and survival in uveal melanoma (UM). METHODS: Thirty-six patients with UM were selected based on the metastatic status, and clinicopathological data were collected. Multiplex ligation-dependent probe amplification (MLPA) was used to identify chromosomal changes. Chromosomal changes and clinicopathological data were correlated with survival and metastasis. The microRNA expression was analysed in 26 of the 36 archived UM samples. Unsupervised analysis, differential expression analysis and Cox regression analysis were performed to determine the association with metastasis and survival. RESULTS: Metastasis and metastatic death occurred in 20 patients, two patients died of other causes and one patient of unknown causes. A significant association between increasing size category (p = 0.002, log-rank), extraocular extension (p = 0.001), chromosome 3 loss (p = 0.033) and 1p loss (p = 0.030) and development of metastases was observed. Tumour, node, metastasis (TNM) staging showed a significant association with survival (p < 0.0001, log-rank). Adjusting for gender and age TNM size category T4 (p = 0.016, Cox regression analysis), mixed (p = 0.029) and epithelioid (p = 0.0058) cell types, chromosome 3 loss (p = 0.014) and 8q gain (p = 0.010) were significant prognosticators for a poor survival. Hierarchical clustering divided the UM into three groups based on microRNA expression. The clusters showed no association with clinical or histopathological features, TNM staging, metastasis or survival. Differential expression analysis did not reveal microRNAs related to metastasis or survival. CONCLUSIONS: The prognostic significance of chromosome 3 loss and 8q gain identified by MLPA analysis was confirmed in archived UM samples. The value of microRNA expression as a predictor of metastasis and survival in UM could not be confirmed.

cMyc/miR-125b-5p signalling determines sensitivity to bortezomib in preclinical model of cutaneous T-cell lymphomas.

Successful/effective cancer therapy in low grade lymphoma is often hampered by cell resistance to anti-neoplastic agents. The crucial mechanisms responsible for this phenomenon are poorly understood. Overcoming resistance of tumor cells to anticancer agents, such as proteasome inhibitors, could improve their clinical efficacy. Using cutaneous T-cell lymphoma (CTCL) as a model of the chemotherapy-resistant peripheral lymphoid malignancy, we demonstrated that resistance to proteasome inhibition involved a signaling between the oncogene cMyc and miR-125b-5p. Bortezomib repressed cMyc and simultaneously induced miR-125b-5p that exerted a cytoprotective effect through the downmodulation of MAD4. Overexpression of cMyc repressed miR-125b-5p transcription and sensitized lymphoma cells to bortezomib. The central role of miR-125b-5p was further confirmed in a mouse model of T-cell lymphoma, where xenotransplantation of human CTCL cells overexpressing miR-125b-5p resulted in enhanced tumor growth and a shorter median survival. Our findings describe a novel mechanism through which miR-125b-5p not only regulates tumor growth in vivo, but also increases cellular resistance to proteasome inhibitors via modulation of MAD4.

MDM2 inhibitor nutlin-3a induces apoptosis and senescence in cutaneous T-cell lymphoma: role of p53.

P53 is rarely mutated in cutaneous T-cell lymphoma (CTCL) and is therefore a promising target for innovative therapeutic approaches. Nutlin-3a is an inhibitor of MDM2 (human homolog of murine double minute 2), which disrupts its interaction with p53, leading to the stabilization and activation of p53. To investigate the potential therapeutic use of nutlin-3a in CTCL, we screened CTCL lines Hut-78, SeAx, MyLa2000, Mac1, and Mac2a by measuring p53 levels after nutlin-3a treatment. In MyLa2000, Mac1, and Mac2a, we observed the increase in p53, indicating the fully functional p53. In the remaining cell lines, P53 mutation analysis identified a homozygous nonsense mutation (R196Stop in Hut-78) and a homozygous missense mutation (G245S in SeAx). In MyLa2000, Mac1, and Mac2a carrying wild-type P53, nutlin-3a induced apoptosis and senescence demonstrated by permanent G0/G1 cell-cycle block and expression of the senescence-associated ß-galactosidase. This effect was abolished in cells in which p53 was silenced by small interfering RNA. Sézary cells lack functional p53 and were resistant to nutlin-3a. However, nutlin-3a potentiated the efficacy of conventional chemotherapeutics not only in cells with intact p53 but also in Hut-78, SeAx, and Sézary cells. Thus, targeting p53 by nutlin-3a may constitute a therapeutic approach in CTCL because of increased apoptosis and senescence of tumor cells.

miR-122 regulates p53/Akt signalling and the chemotherapy-induced apoptosis in cutaneous T-cell lymphoma.

Advanced cutaneous T-cell lymphoma (CTCL) is resistant to chemotherapy and presents a major area of medical need. In view of the known role of microRNAs (miRNAs) in the regulation of cellular signalling, we aimed to identify the functionally important miRNA species, which regulate apoptosis in CTCL. Using a recently established model in which apoptosis of CTCL cell lines is induced by Notch-1 inhibition by γ-secretase inhibitors (GSIs), we found that miR-122 was significantly increased in the apoptotic cells. miR-122 up-regulation was not specific for GSI-1 but was also seen during apoptosis induced by chemotherapies including doxorubicin and proteasome blockers (bortezomib, MG132). miR-122 was not expressed in quiescent T-cells, but was detectable in CTCL: in lesional skin in mycosis fungoides and in Sézary cells purified from peripheral blood. In situ hybridization results showed that miR-122 was expressed in the malignant T-cell infiltrate and increased in the advanced stage mycosis fungoides. Surprisingly, miR-122 overexpression decreased the sensitivity to the chemotherapy-induced apoptosis via a signaling circuit involving the activation of Akt and inhibition of p53. We have also shown that induction of miR-122 occurred via p53 and that p53 post-transcriptionally up-regulated miR-122. miR-122 is thus an amplifier of the antiapoptotic Akt/p53 circuit and it is conceivable that a pharmacological intervention in this pathway may provide basis for novel therapies for CTCL.

MicroRNA miR-125b induces senescence in human melanoma cells.

MicroRNAs (miRNAs) are small noncoding RNA molecules involved in gene regulation. Aberrant expression of miRNA has been associated with the development or progression of several diseases, including cancer. In a previous study, we found that the expression of miRNA-125b (miR-125b) was two-fold lower in malignant melanoma producing lymph node micrometastases than in nonmetastasizing tumors. To get further insight into the functional role of miR-125b, we assessed whether its overexpression or silencing affects apoptosis, proliferation, or senescence in melanoma cell lines. We showed that overexpression of miR-125b induced typical senescent cell morphology, including increased cytoplasmatic/nucleus ratio and intensive cytoplasmatic ß-galactosidase expression. In contrast, inhibition of miR-125b resulted in 30-35% decreased levels of spontaneous apoptosis. We propose that downregulation of miR-125b in an early cutaneous malignant melanoma can contribute to the increased metastatic capability of this tumor.

Growth dynamics and cyclin expression in cutaneous T-cell lymphoma cell lines.

We have investigated cell growth dynamics and cyclins B1 and E expression in cell lines derived from mycosis fungoides (MyLa), Sézary syndrome (SeAx), and CD30(+) lympho-proliferative diseases (Mac1, Mac2a, JK). Mac1 and Mac2a had the highest growth rate (doubling time 18-28 h, >90% cycling cells) whereas SeAx was proliferating slowly (doubling time 55 h, approximately 35% cycling cells). Expression of cyclin B1 correlated positively with doubling time whereas expression of cyclin E was unscheduled and constant across the investigated cell lines. All cell lines exhibited high expression of PCNA. Thus, we concluded that cyclin B1 could be used for rapid screening of cell proliferation in malignant lymphocytes derived from cutaneous T-cell lymphoma.