Transdermal administration of farnesol-ethosomes enhances the treatment of cutaneous candidiasis induced by Candida albicans in mice

Cutaneous candidiasis, caused by Candida albicans, is a severe and frustrating condition, and finding effective treatments can be challenging. Therefore, the development of farnesol-loaded nanoparticles is an exciting breakthrough. Ethosomes are a novel transdermal drug delivery carrier that incorporates a certain concentration (10-45%) of alcohols into lipid vesicles, resulting in improved permeability and encapsulation rates compared to conventional liposomes. Farnesol is a quorum-sensing molecule involved in morphogenesis regulation in C. albicans, and these ethosomes offer a promising new approach to treating this common fungal infection. This study develops the formulation of farnesol-loaded ethosomes (farnesol-ethosomes) and assesses applications in treating cutaneous candidiasis induced by C. albicans in vitro and in vivo. Farnesol-ethosomes were successfully developed by ethanol injection method. Therapeutic properties of farnesol-ethosomes, such as particle size, zeta potential, and morphology, were well characterized. According to the results, farnesol-ethosomes demonstrated an increased inhibition effect on cells' growth and biofilm formation in C. albicans. In Animal infection models, treating farnesol-ethosomes by transdermal administration effectively relieved symptoms caused by cutaneous candidiasis and reduced fungal burdens in quantity. We also observed that ethosomes significantly enhanced drug delivery efficacy in vitro and in vivo. These results indicate that farnesol-ethosomes can provide future promising roles in curing cutaneous candidiasis.

IMPORTANCE

Cutaneous candidiasis attributed to Candida infection is a prevalent condition that impacts individuals of all age groups. As a type of microbial community, biofilms confer benefits to host infections and mitigate the clinical effects of antifungal treatments. In C. albicans, the yeast-to-hypha transition and biofilm formation are effectively suppressed by farnesol through its modulation of multiple signaling pathway. However, the characteristics of farnesol such as hydrophobicity, volatility, degradability, and instability in various conditions can impose limitations on its effectiveness. Nanotechnology holds the potential to enhance the efficiency and utilization of this molecule. Treatment of farnesol-ethosomes by transdermal administration demonstrated a very remarkable therapeutic effect against C. albicans in infection model of cutaneous candidiasis in mice. Many patients suffering fungal skin infection will benefit from this study.

Evaluation of farnesol orally and topically against experimental cutaneous leishmaniasis: In -vivo analysis

Leishmaniasis is a zoonotic disease transmitted by an obligate intra-macrophage protozoan of the genus Leishmania through the infective bite of a vector sandfly. This study investigated the therapeutic efficacy of farnesol, a sesquiterpene compound, for the treatment of cutaneous leishmaniasis (CL) using in vivo BALB/c mouse model. In this study, farnesol's efficacy was compared with the standard drug, paromomycin. It was observed that farnesol significantly reduced lesion sizes and footpad thickness compared to the control group (paromomycin). Lymph node size was also significantly reduced in farnesol-treated mice, indicating its ability to control infection spread. Combination therapy with farnesol and Paromomycin did not demonstrate synergistic effects. These results highlight the potential of farnesol as an alternative therapeutic agent for CL. Further investigations are required to elucidate its mechanism of action and assess potential off-target effects. Optimization of oral delivery methods should be explored to enhance bioavailability. Overall, our findings support farnesol's efficacy in CL treatment, offering promising prospects for improved disease management.

In vivo antifungal activities of farnesol combined with antifungal drugs against murine oral mucosal candidiasis

The antifungal resistence of oral candidiasis is a serious clinical issue. The in vivo efficacy of farnesol combined with antifungals for oral candidiasis remains unknown. The possible therapeutic effects of a combination of farnesol and antifungal drugs and the regulation of inflammatory cytokines in murine oral candidiasis were investigated in this study. An experimental oral candidiasis model was constructed using ICR mice. Farnesol at 25 and 50 μM did not change IL-17, IFN-γ and TNF-α production during oral candidiasis compared with that of the control infected mice. The co-applications of farnesol (50 μM) and nystatin, farnesol (4 μM, 8 μM) and itraconazole, farnesol (25, 50 μM), and fluconazole enhanced the therapeutic activity of the antifungal agents alone against oral candidiasis. The effective combinations reduced the number of colony forming units (CFU) of Candida albicans isolated from the oral cavity and oral lesions on the tongue.

Potential Anti-Inflammatory and Anti-Cancer Properties of Farnesol

Farnesol, an acyclic sesquiterpene alcohol, is predominantly found in essential oils of various plants in nature. It has been reported to exhibit anti-cancer and anti-inflammatory effects, and also alleviate allergic asthma, gliosis, and edema. In numerous tumor cell lines, farnesol can modulate various tumorigenic proteins and/or modulates diverse signal transduction cascades. It can also induce apoptosis and downregulate cell proliferation, angiogenesis, and cell survival. To exert its anti-inflammatory/anti-oncogenic effects, farnesol can modulate Ras protein and nuclear factor kappa-light-chain-enhancer of activated B cells activation to downregulate the expression of various inflammatory mediators such as cyclooxygenase-2, inducible nitric oxide synthase, tumor necrosis factor alpha, and interleukin-6. In this review, we describe the potential mechanisms of action underlying the therapeutic effects of farnesol against cancers and inflammatory disorders. Furthermore, these findings support the clinical development of farnesol as a potential pharmacological agent in clinical studies.

Evaluation of the UVB-screening capacity and restorative effects exerted by farnesol gel on UVB-caused sunburn

Farnesol, a natural 15-carbon organic compound, has various microbiological and cellular activities. It has been found to exert apoptosis-inducing effects against carcinoma cells as well as antiallergic and anti-inflammatory effects in vivo. In the current study, a series of formulations composed of various concentrations of hydroxypropyl methylcellulose (HPMC) with the addition of hyaluronan (HA) and xanthan gum (XG) was designed to evaluate the UVB-screening and H₂ O₂ -eliminating effects of farnesol in normal fibroblasts. Farnesol at 0.005, 0.0075, and 0.01% exhibited significant capacity for H₂ O₂ scavenging; at 0.0025%, it showed insignificant effects. Under 120-min UVB exposure, screening with plural gel composed of 0.0025% farnesol, 0.5% HA, and 0.5% XG containing 1.5% or 2% HPMC retained normal fibroblast viability. After 60-min exposure to UVB, screening with plural gel composed of farnesol, HA, XG, and 0.5%, 1.0%, 1.5%, or 2% HPMC decreased the ratio of the G1 phase and increased ratio of the S phase in comparison with the accumulated cell cycle of the normal fibroblasts without screening. The gel with 2% HPMC displayed the strongest cell cycle-reversal ability. In vivo histopathological results showed that the prepared plural gels with 0.5% or 2% HPMC and farnesol, HA, and XG had greater antiphotoaging and reparative effects against UVB-induced changes and damage in the skin. In conclusion, the current in vitro and in vivo results demonstrated that the prepared plural composed of 0.0025% farnesol, 0.5% HA, 0.5% XG, and 2% HPMC possessed the greatest UVB-screening capacity and the strongest restorative effects on UVB-induced sunburned skin.

Farnesol, a sesquiterpene alcohol in essential oils, ameliorates serum allergic antibody titres and lipid profiles in ovalbumin-challenged mice

BACKGROUND

Farnesol, a natural sesquiterpene alcohol in essential oils, was found to have potential for alleviating massive inflammation, oxidative stress and lung injury. However, effects of farnesol supplementation on allergic asthma remain unclear.

OBJECTIVES

To clarify the puzzle, this work investigates the effects of farnesol on allergic asthma using an ovalbumin (OVA)-sensitised and challenged mouse model.

METHODS

Farnesol was administered to OVA-sensitised and challenged mice for 5 weeks. Three farnesol doses, namely 5, 25 and 100mg farnesol/kg BW/day, non-sensitised control, dietary control, and positive control (dexamethasone 3mg/kg BW by gavage) were included. Sera and bronchoalveolar lavage fluids from the experimental mice were collected to measure farnesol concentrations, serum lipid profiles, antibody titres, differential cell counts or Th1/Th2 cytokines levels.

RESULTS

The results showed that farnesol supplementation increased serum farnesol concentration dose-dependently, significantly increased (P<0.05) OVA-specific IgG2a/IgE antibody titre ratios, but decreased total IgE levels. Farnesol supplementation markedly reversed the aberrated LDL-c/HDL-c and HDL-c/TC ratios in the sera of asthmatic mice, suggesting that farnesol supplementation might ameliorate serum lipid profiles in the OVA-sensitised and challenged mice.

CONCLUSION

Our results evidenced that farnesol supplementation might improve serum allergic antibody titres and lipid profiles in asthmatic mice.

Cardioprotection by farnesol: role of the mevalonate pathway

PURPOSE

Farnesol is a key metabolite of the mevalonate pathway and known as an antioxidant. We examined whether farnesol treatment protects the ischemic heart.

METHODS

Male Wistar rats were treated orally with 0.2, 1, 5, and 50 mg/kg/day farnesol/vehicle for 12 days, respectively. On day 13, the effect of farnesol treatment on cardiac ischemic tolerance and biochemical changes was tested. Therefore, hearts were isolated and subjected either to 30 min coronary occlusion followed by 120 min reperfusion to measure infarct size or to 10 min aerobic perfusion to measure cardiac mevalonate pathway end-products (protein prenylation, cholesterol, coenzyme Q9, coenzyme Q10, dolichol), and 3-nitrotyrosine (oxidative/nitrosative stress marker), respectively. The cytoprotective effect of farnesol was also tested in cardiomyocytes subjected to simulated ischemia/reperfusion.

RESULTS

Farnesol pretreatment decreased infarct size in a U-shaped dose-response manner where 1 mg/kg/day dose reached a statistically significant reduction (22.3±3.9% vs. 40.9±6.1% of the area at risk, p<0.05). Farnesol showed a similar cytoprotection in cardiomyocytes. The cardioprotective dose of farnesol (1 mg/kg/day) significantly increased the marker of protein geranylgeranylation, but did not influence protein farnesylation, cardiac tissue cholesterol, coenzyme Q9, coenzyme Q10, and dolichol. While the cardioprotective dose of farnesol did not influence 3-nitrotyrosine, the highest dose of farnesol (50 mg/kg/day) tested did not show cardioprotection, however, it significantly decreased cardiac 3-nitrotyrosine.

CONCLUSIONS

This is the first demonstration that oral farnesol treatment reduces infarct size. The cardioprotective effect of farnesol likely involves increased protein geranylgeranylation and seems to be independent of the antioxidant effect of farnesol.

Farnesol, an isoprenoid, improves metabolic abnormalities in mice via both PPARα-dependent and -independent pathways

Peroxisome proliferator-activated receptors (PPARs) control energy homeostasis. In this study, we showed that farnesol, a naturally occurring ligand of PPARs, could ameliorate metabolic diseases. Obese KK-Ay mice fed a high-fat diet (HFD) containing 0.5% farnesol showed significantly decreased serum glucose level, glucosuria incidence, and hepatic triglyceride contents. Farnesol-containing HFD upregulated the mRNA expressions of PPARα target genes involved in fatty acid oxidation in the liver. On the other hand, farnesol was not effective in upregulating the mRNA expressions of PPARγ target genes in white adipose tissues. Experiments using PPARα-deficient [(-/-)] mice revealed that the upregulation of fatty acid oxidation-related genes required PPARα function, but the suppression of hepatic triglyceride accumulation was partially PPARα-dependent. In hepatocytes isolated from the wild-type and PPARα (-/-) mice, farnesol suppressed triglyceride synthesis. In luciferase assay, farnesol activated both PPARα and the farnesoid X receptor (FXR) at similar concentrations. Moreover, farnesol increased the mRNA expression level of a small heterodimer partner known as one of the FXR target genes and decreased those of sterol regulatory element-binding protein-1c and fatty acid synthase in both the wild-type and PPARα (-/-) hepatocytes. These findings suggest that farnesol could improve metabolic abnormalities in mice via both PPARα-dependent and -independent pathways and that the activation of FXR by farnesol might contribute partially to the PPARα-independent hepatic triglyceride content-lowering effect. To our knowledge, this is the first study on the effect of the dual activators of PPARα and FXR on obesity-induced metabolic disorders.

Ras inhibition induces insulin sensitivity and glucose uptake

Background

Reduced glucose uptake due to insulin resistance is a pivotal mechanism in the pathogenesis of type 2 diabetes. It is also associated with increased inflammation. Ras inhibition downregulates inflammation in various experimental models. The aim of this study was to examine the effect of Ras inhibition on insulin sensitivity and glucose uptake, as well as its influence on type 2 diabetes development.

Methods and Findings

The effect of Ras inhibition on glucose uptake was examined both in vitro and in vivo. Ras was inhibited in cells transfected with a dominant-negative form of Ras or by 5-fluoro-farnesylthiosalicylic acid (F-FTS), a small-molecule Ras inhibitor. The involvement of IκB and NF-κB in Ras-inhibited glucose uptake was investigated by immunoblotting. High fat (HF)-induced diabetic mice were treated with F-FTS to test the effect of Ras inhibition on induction of hyperglycemia. Each of the Ras-inhibitory modes resulted in increased glucose uptake, whether in insulin-resistant C2C12 myotubes in vitro or in HF-induced diabetic mice in vivo. Ras inhibition also caused increased IκB expression accompanied by decreased expression of NF-κB . In fat-induced diabetic mice treated daily with F-FTS, both the incidence of hyperglycemia and the levels of serum insulin were significantly decreased.

Conclusions

Inhibition of Ras apparently induces a state of heightened insulin sensitization both in vitro and in vivo. Ras inhibition should therefore be considered as an approach worth testing for the treatment of type 2 diabetes.

Phase 1 first-in-human clinical study of S-trans,trans-farnesylthiosalicylic acid (salirasib) in patients with solid tumors

PURPOSE

This phase I first-in-human trial evaluated salirasib, an S-prenyl derivative of thiosalicylic acid that competitively blocks RAS signaling.

METHODS

Patients with advanced cancers received salirasib twice daily for 21 days every 4 weeks. Doses were escalated from 100 to 200, 400, 600, and 800 mg.

RESULTS

The most common toxicity was dose-related diarrhea (Grade 1-2, 79% of 24 patients). Other toxicities included abdominal pain, nausea, and vomiting. No Grade 3-4 toxicity was noted. Nineteen (79%) patients had no drug-related toxicity >Grade 1. Dose-limiting toxicity (DLT) was not reached, but all three patients treated with 800 mg experienced Grade 1-2 diarrhea, brogating dose escalation. Six patients were treated at a dose of 600 mg with no DLTs. Seven (29%) patients had stable disease on salirasib for ≥4 months (range 4-23+). The salirasib pharmacokinetic profile was characterized by slow absorption and a rapid elimination phase following oral administration. Salirasib exposure (C(max); day 1 AUC(inf) vs. day 15 AUC(0-12 h)) was similar between days 1 and 15 (P > 0.05). The T(1/2) (mean ± SD) was 3.6 ± 2.2 h on day 1.

CONCLUSIONS

Salirasib therapy was well tolerated. The recommended dose for phase II studies is 600 mg twice daily.

The Ras antagonist, farnesylthiosalicylic acid (FTS), decreases fibrosis and improves muscle strength in dy/dy mouse model of muscular dystrophy

The Ras superfamily of guanosine-triphosphate (GTP)-binding proteins regulates a diverse spectrum of intracellular processes involved in inflammation and fibrosis. Farnesythiosalicylic acid (FTS) is a unique and potent Ras inhibitor which decreased inflammation and fibrosis in experimentally induced liver cirrhosis and ameliorated inflammatory processes in systemic lupus erythematosus, neuritis and nephritis animal models. FTS effect on Ras expression and activity, muscle strength and fibrosis was evaluated in the dy^2J/dy^2J mouse model of merosin deficient congenital muscular dystrophy. The dy^2J/dy^2J mice had significantly increased RAS expression and activity compared with the wild type mice. FTS treatment significantly decreased RAS expression and activity. In addition, phosphorylation of ERK, a Ras downstream protein, was significantly decreased following FTS treatment in the dy^2J/dy^2J mice. Clinically, FTS treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter. Significant reduction of fibrosis was demonstrated in the treated group by quantitative Sirius Red staining and lower muscle collagen content. FTS effect was associated with significantly inhibition of both MMP-2 and MMP-9 activities. We conclude that active RAS inhibition by FTS was associated with attenuated fibrosis and improved muscle strength in the dy^2J/dy^2J mouse model of congenital muscular dystrophy.

Differential effects of ibandronate, docetaxel and farnesol treatment alone and in combination on the growth of prostate cancer cell lines

Ibandronate, one of the most potent bisphosphonates, has been shown to inhibit growth of various cancer cell lines. In contrast, little is known about the effects of ibandronate on prostate cancer cells. Therefore the aim of our study was to characterize the effects of ibandronate alone and in combination with docetaxel on the growth of prostate cancer cell lines and to identify the underlying signalling pathways. Material and methods. The prostate cancer cell lines LNCaP and PC-3 were treated with increasing concentrations of ibandronate and docetaxel alone and in combination. Viable cell number was measured after five days using a hemocytometer and the MTT-method. The effects of ibandronate were tentatively antagonized by addition of farnesyl-pyrophosphate (FPP) or farnesol (FOH). Results. Ibandronate inhibits growth of both prostate cancer cell lines in a dose dependent manner. In combination with docetaxel, synergistic effects are found as evidenced by a combination index (CI) of <1. Addition of FOH and FPP completely antagonized the growth inhibitory effects of ibandronate on both cell lines. Surprisingly, in combination with ibandronate and docetaxel, FOH further increased growth inhibition instead of antagonizing the growth inhibitory effects of ibandronate. Furthermore, FOH alone appeared to be a potent inhibitor of tumor cell growth. Discussion. Ibandronate effectively inhibits growth of prostate cancer cell lines via inhibition of the farnesyl-IPP-synthase and exhibits synergistic effects with docetaxel. In addition, FOH is a potent inhibitor of prostate cancer cell lines and may display an interesting treatment option for patients with CRPC.

Neuroprotective Effects of the Ras Inhibitor S-Trans-Trans-Farnesylthiosalicylic Acid, Measured by Diffusion-Weighted Imaging after Traumatic Brain Injury in Rats

Ras proteins play a role in receptor-mediated signaling pathways and are activated after traumatic brain injury. S-trans-trans-farnesylthiosalicylic acid (FTS), a synthetic Ras inhibitor, acts primarily on the active, GTP-bound form of Ras and was shown to improve neurobehavioral outcome after closed head injury (CHI) in mice. To gain a better understanding of the neuroprotective mechanism of FTS, we used diffusion-weighted imaging (DWI) in a rat model of CHI. Apparent diffusion coefficients (ADC) and transverse relaxation times (T2) were measured in injured rat brains after treatment with vehicle or FTS (5 mg/kg). Neuroprotection by FTS was also assessed in terms of the neurological severity score. One week after injury, significantly better recovery was observed in the FTS-treated rats than in the controls (p = 0.0191). T2 analysis of the magnetic resonance images revealed no differences between the two groups. In contrast, they differed significantly in ADC, particularly at 24 h post-CHI (p < 0.05): in the vehicle-treated rats ADC had decreased to approximately 26% below baseline, whereas it had increased to about 10% above baseline in the FTS-treated rats. As the magnitude of ADC reduction is strongly linked to blood perfusion deficit, these results suggest that the neuroprotective mechanism of FTS might be related to an improvement in cerebral perfusion. We propose that FTS, which is currently being tested in humans for anti-cancer indications, should also be considered as a new strategy for the management of head injury.

The Ras inhibitor farnesylthiosalicylic acid as a potential therapy for neurofibromatosis type 1

PURPOSE

Farnesylthiosalicylic acid (FTS) is a Ras inhibitor that dislodges all active Ras isoforms from the membrane. We assessed the ability of FTS to reverse the transformed phenotype of neurofibromatosis type 1 (NF1)-associated tumor cell lines of malignant peripheral nerve sheath tumor (MPNST).

EXPERIMENTAL DESIGN

nf1 mutations were genotyped, allelic losses were analyzed, and neurofibromin expression levels were determined in MPNST cell lines ST88-14, S265P21, and 90-8. The effects of FTS on GTP-bound Ras (Ras-GTP) and its prominent downstream targets, as well as on cell morphology, anchorage-dependent and anchorage-independent growth, and tumor growth in mice, were assessed.

RESULTS

The MPNST cell lines were biallelic, NF1 inactive, and neurofibromin deficient. We show that FTS treatment shortened the relatively long duration of Ras activation and signaling to extracellular signal-regulated kinase, Akt, and RalA in all NF1-deficient MPNST cell lines (NF1 cells) to that observed in a non-NF1, normally expressing neurofibromin MPNST cell line. These effects of FTS led to lower steady-state levels of Ras-GTP and its activated targets. Both anchorage-dependent and anchorage-independent growth of NF1 cells were dose dependently inhibited by FTS, and the inhibition correlated positively with Ras-GTP levels. NF1 cells were found to possess strong actin stress fibers, and this phenotype was also corrected by FTS. NF1 tumor growth in a nude mouse model was inhibited by oral FTS.

CONCLUSIONS

FTS treatment of NF1 cells normalized Ras-GTP levels, resulting in reversal of the transformed phenotype and inhibition of tumor growth. FTS may therefore be considered as a potential drug for the treatment of NF1.

Farnesyl thiosalicylic acid chemosensitizes human melanoma in vivo

Malignant melanoma is well known for its poor response to a variety of chemotherapeutic agents. Testing of numerous treatment strategies has identified dacarbazine as the most active single drug; however, its response rates in various clinical settings are quite limited. Defective apoptosis in combination with oncogenic proteins (such as activated Ras) in cell proliferation pathways plays a key part in both the development and disease progression of human melanoma. Farnesyl thiosalicylic acid, a novel Ras inhibitor, dislodges Ras proteins from the cell membrane, leading to inhibition of cell transformation and tumor growth. In this study we evaluated the effect of farnesyl thiosalicylic acid treatment on established human melanoma xenografts grown in mice with severe combined immunodeficiency as well as the chemosensitizing effect of farnesyl thiosalicylic acid in combination with dacarbazine. Daily administration of 10, 20, or 40 mg per kg of farnesyl thiosalicylic acid resulted in a concentration-dependent reduction in tumor growth, with growth inhibition reaching a mean value of 45+/-7%, at the highest concentration. The combination of farnesyl thiosalicylic acid (10 mg per kg per day) and dacarbazine (80 mg per kg per day) resulted in a significant reduction of 56%+/-9%, in mean tumor growth. Analysis of toxicologic parameters (mouse weight, blood cell counts, and blood chemistry) showed an acceptable and similar toxicity profile for both the single-agent farnesyl thiosalicylic acid treatment and the combination of farnesyl thiosalicylic acid plus dacarbazine treatment. Given the observed preclinical treatment responses and the low toxicity, our results support the notion that farnesyl thiosalicylic acid in combination with dacarbazine may qualify as a rational treatment approach for human melanoma.

Effects of apigenin and tt-farnesol on glucosyltransferase activity, biofilm viability and caries development in rats

Propolis, a resinous hive product secreted by Apis mellifera bees, has been shown to reduce the incidence of dental caries in rats. Several compounds, mainly polyphenolics, have been identified in propolis. Apigenin and tt-farnesol demonstrated biological activity against mutans streptococci. We determined here their effects, alone or in combination, on glucosyltransferase activity, biofilm viability, and development of caries in rats. Sprague-Dawley rats were infected with Streptococcus sobrinus 6715 and treated topically twice daily as follows: (1) tt-farnesol, (2) apigenin, (3) vehicle control, (4) fluoride, (5) apigenin +tt-farnesol, and (6) chlorhexidine. Apigenin (1.33 mM) inhibited the activity of glucosyltransferases in solution (90-95%) and on the surface of saliva-coated hydroxyapatite beads (35-58%); it was devoid of antibacterial activity. tt-Farnesol (1.33 mM) showed modest antibacterial activity against biofilms and its effects on glucosyltransferases were minimal. The incidence of smooth-surface caries was significantly reduced by apigenin +tt-farnesol (60%), fluoride (70%), and chlorhexidine (72%) treatments compared to control (P < 0.05).

Treatment of the chronic inflammation in peripheral target tissue improves the crushed nerve recovery in the rat: histopathological assessment of the nerve recovery

An experimental study was performed to investigate the influence of subsidence of chronic inflammation in peripheral target tissue on the recovery of crushed nerve. Seventy-eight male Wistar rats weighing 300-370 g were used. The sciatic nerve was operatively crushed unilaterally with an aneurysm clip (250 gf) applied for 5 min. Chronic inflammation, localized to the ankle, was induced by intra-articular injection of complete Freund's adjuvant 1 week preoperatively. Prednisolone farnesylate (PNF-21) 1.4% gel was applied on the ankle as an anti-inflammatory agent for consecutive days after the operation. The animals were divided into five groups as follows: crush injury with ipsilateral arthritis (CIA); crush injury with ipsilateral arthritis and PNF-21 gel applied on the ipsilateral ankle (CIA + IPNF); crush injury with ipsilateral arthritis and PNF-21 gel applied on the contralateral ankle (CIA + CPNF); crush injury with contralateral arthritis (CCA); crush injury without arthritis (C). Specimens for histopathological examination were taken from the nerve at a site 5 mm distal to the crush lesion at 4 weeks postoperatively. The average axon diameter was significantly larger in the CIA + IPNF group than in the CIA group (p < 0.01). No significant difference was observed between the CIA + CPNF group and the CIA group. In conclusion, chronic inflammation in peripheral target tissue suppresses recovery of the crushed nerve, and subsidence of this chronic inflammation improves this suppression histopathologically.

Treatment of MRL/lpr mice, a genetic autoimmune model, with the Ras inhibitor, farnesylthiosalicylate (FTS)

Activation and proliferation of lymphocytes requires the active signal transducer Ras. Activation of lymphocytes, associated with autoimmunity, may therefore be modified by S-farnesylthiosalicylic acid (FTS), a synthetic substance that detaches Ras from the inner cell membrane and induces its rapid degradation. The MRL/lpr mouse is a genetic model of a generalized autoimmune disease sharing many features and organ pathology with systemic lupus erythematosus (SLE) and the primary antiphospholipid syndrome (APS). The objective of the present study was to examine the effect of FTS on laboratory and clinical pathology in the MRL/lpr mouse. Female MRL/lpr (n = 50) and MRL/++ control (n = 35) mice were treated intraperitoneally with either FTS (5 mg/kg/day) or saline between 6 and 18 weeks of age. The mice were weighed, tested for proteinuria and lymphadenopathy, lymphocyte proliferation, antibodies, grip strength and behaviour in an open field. FTS treatment resulted in a 50% decrease in splenocyte proliferation to ConA, LPS and a disease specific antigen, beta(2)-glycoprotein-I, and in a significant decrease in serum antibody levels against cardiolipin and dsDNA. Proteinuria and grip strength were normalized and lymphadenopathy and postmortem lymph node and spleen weights were significantly reduced in FTS treated MRL/lpr mice. These findings indicate that modulation of Ras activation has a significant impact on the MRL/lpr model and may represent a new therapeutic approach for the treatment of systemic autoimmune diseases such as SLE and APS.

A novel Ras antagonist regulates both oncogenic Ras and the tumor suppressor p53 in colon cancer cells

BACKGROUND

In colon cancer, K-Ras oncogenes, which appear to be linked to chemoresistance and poor prognosis, are activated in more than 50% of cases, whereas the tumor suppressor gene p53 is mutationally altered in about 70% of all cases. The transcription factor p53, which is frequently mutated at codon 273, maintains wild-type configuration and possibly carries out residual functions. Although blocking of activated K-Ras may constitute a rational therapeutic concept for this treatment-resistant malignancy, a strategy influencing both oncogenic Ras and the tumor suppressor p53 may be even more promising.

MATERIALS AND METHODS

We evaluated the effects of S-trans, trans-farnesyl-thiosalicylic acid (FTS), a novel Ras antagonist on human SW480 and HT-29 colon cancer cells, which both harbor a p53 His273 mutation but express activated K-Ras and wild-type, but overexpressed, H-Ras, respectively. Besides cell growth and morphology, levels of cellular Ras proteins, regulation of p53 and p21(waf1/cip1) expression were analyzed by immunoblotting. The cell cycle arresting potential of FTS was quantified by flow cytometry.

RESULTS

We demonstrate that FTS treatment alters the morphology and blocks the growth of SW480 and HT-29 colon cancer cells by both reducing the total amount of Ras and up-regulating the tumor suppressor p53. Furthermore, FTS caused an upregulation of the cyclin-cyclin-dependent kinase (CDK) inhibitor p21(waf1/cip1) and blocked the cell cycle. p53 antisense oligonucleotides not only reduced the level of p53 proteins but correspondingly also blocked the expression of p21(waf1/cip1) in FTS-treated colon cancer cells.

CONCLUSIONS

FTS, a unique compound capable of regulating both oncogenic Ras and the tumor suppressor p53 may prove particularly useful for the therapy of colon cancer and other treatment-resistant malignancies where Ras is altered and p53 is either wild-type or mutated in positions that allow residual p53 functions.

The Ras antagonist, farnesylthiosalicylic acid (FTS), inhibits experimentally-induced liver cirrhosis in rats

BACKGROUND/AIMS

Protooncogenes may play an important role, not only in carcinogenesis, but also in the regulation of normal cellular proliferation and differentiation. Several studies have indicated increased expression of the Ras protooncogenes in the liver in animal models and in patients with liver cirrhosis. The aim of the present study was to examine whether a synthetic Ras antagonist, S-farnesylthiosalicylic acid (FTS), which specifically dislodges Ras from the membrane of Ras-transformed fibroblasts (EJ cells), can prevent experimentally-induced liver cirrhosis in rats.

METHODS

Cirrhosis was induced in male Wistar rats by intraperitoneal administration of thioacetamide (200 mg/kg twice weekly for 12 weeks). The Ras antagonist, farnesylthiosalicylic acid (FTS, 5 mg/kg), was administered during the study period 3 times a week. Ras expression in the liver was determined by Western blot analysis with pan anti-Ras antibodies and by immunohistochemistry.

RESULTS

Rats treated with thioacetamide and the Ras antagonist, farnesylthiosalicylic acid (FTS), for 12 weeks had lower histopathologic scores of fibrosis and inflammation (p-values of 0.003 and 0.008, respectively) than those treated with thioacetamide only. There were no differences between the histopathologic scores in vehicle (control) and in Ras-antagonist (FTS) only treatments. Analysis of hepatic hydroxyproline levels from the two thioacetamide-treated groups and controls confirmed the histopathologic scores (7.7+/-0.9 mg/g protein in the TAA-treated vs. 3.8+/-0.5 mg/g protein in the TAA+FTS treated group, p = 0.007). Ras levels, determined by Western blot analysis, were markedly increased in the livers treated with TAA (17-fold over control) and significantly decreased (by about 70%) in the livers of rats treated with TAA and FTS. Studies in isolated human hepatic stellate cells demonstrated that FTS inhibited both DNA synthesis and migration of those cells (p<0.05).

CONCLUSION

These results indicate that inhibition of Ras expression in the liver during fibrogenesis, prevents the development of experimentally-induced hepatic cirrhosis.

Farnesylthiosalicylic acid inhibits the growth of human Merkel cell carcinoma in SCID mice

Merkel cell carcinoma (MCC) is a neuroendocrine malignancy showing poor response to a variety of therapeutic strategies. We evaluated the antitumor activity of S-trans, trans-farnesylthiosalicylic acid (FTS), a new inhibitor of Ras signal transduction, in a newly established SCID mouse xenotransplantation model for human MCC (seven animals per group). FTS injected intraperitoneally at 5 mg/kg per day for 2 weeks up-regulated the tumor suppressor p53 and induced tumor cell apoptosis in established MCCs growing subcutaneously in SCID mice. These effects led to a statistically significant inhibition of MCC growth (P<0.002). The mean tumor weights following FTS or control treatment were 0.32+/-0.15 g and 1.08+/-0.29 g, respectively. There was no evidence of FTS related toxicity at the effective dose used. Our findings stress the notion that FTS may qualify as a novel and rational treatment approach for MCC and possibly for other tumors that rely on tyrosine kinase signaling.

A new functional Ras antagonist inhibits human pancreatic tumor growth in nude mice

Constitutively active Ras proteins, their regulatory components, and overexpressed tyrosine kinase receptors that activate Ras, are frequently associated with cell transformation in human tumors. This suggests that functional Ras antagonists may have anti-tumor activity. Studies in rodent fibroblasts have shown that S-trans, transfarnesylthiosalicylic acid (FTS) acts as a rather specific nontoxic Ras antagonist, dislodging Ras from its membrane anchorage domains and accelerating its degradation. FTS is not a farnesyltransferase inhibitor, and does not affect Ras maturation. Here we demonstrate that FTS also acts as a functional Ras antagonist in human pancreatic cell lines that express activated K-Ras (Panc-1 and MiaPaCa-2). In Panc-1 cells, FTS at a concentration of 25-100 microM reduced the amount of Ras in a dose-dependent manner and interfered with serum-dependent and epidermal growth factor-stimulated ERK activation, thus inhibiting both anchorage-dependent and anchorage-independent growth of Panc-1 cells in vitro. FTS also inhibited tumor growth in Panc-1 xenografted nude mice, apparently without systemic toxicity. Daily FTS treatment (5 mg/kg intraperitoneally) in mice with tumors (mean volume 0.07 cm3) markedly decreased tumor growth (after treatment for 18 days, tumor volume had increased by only 23+/-30-fold in the FTS-treated group and by 127+/-66-fold in controls). These findings suggest that FTS represents a new class of functional Ras antagonists with potential therapeutic value.

Growth inhibition of ras-dependent tumors in nude mice by a potent ras-dislodging antagonist

A lipophilic farnesyl moiety attached to the carboxyl terminal cysteine of ras proteins structurally supports their membrane anchorage, required for ras-dependent growth-factor signaling and for transforming activity of ras oncoproteins. It has been shown that inhibition of ras farnesylation can block tumor growth in nude mice but that some ras-dependent tumors escape such blockage as a result of prenylation of ras. S-trans-transfarnesylthiosalicylic acid (FTS) is a potent ras-dislodging antagonist that does not affect ras prenylation but rather acts on the mature, membrane-bound ras and facilitates its degradation. Here we demonstrate that FTS induces reappearance of stress fibers in H-ras-transformed rat-1 cells (EJ cells) in vitro, inhibits their anchorage-independent growth in vitro, and blocks EJ-tumor growth in nude mice. The anchorage-independent growth of cells expressing ErbB2 (B104), but not that of v-raf-transformed cells, is also inhibited by FTS, suggesting specificity towards activated ras. FTS treatment (5 mg/kg i.p. daily) caused inhibition (75-80%) of tumor growth in nude mice implanted with EJ, but not in mice implanted with v-raf-transformed cells, with no evidence of systemic toxicity. Moreover, FTS treatment increased the survival rate of EJ-tumor-bearing mice from 48 to 68 days. Here we demonstrate anti-tumor potency in a synthetic, non-toxic, ras-dislodging antagonist acting independently of farnesyltransferases.

Inhibition of pancreatic cancer growth by the dietary isoprenoids farnesol and geraniol

Fruits and vegetables have protective effects against many human cancers, including pancreatic cancer. Isoprenoids are one class of phytochemicals which have antitumor activity, but little is known about their effects on cancer of the pancreas. We tested the hypothesis that isoprenoids would inhibit the growth of pancreatic tumor cells. Significant (60-90%) inhibition of the anchorage-independent growth of human MIA PaCa2 pancreatic tumor cells was attained with 25 microM farnesol, 25 microM geranylgeraniol, 100 microM perillyl amine, 100 microM geraniol, or 300 microM perillyl alcohol. We then tested the relative in vivo antitumor activities of dietary farnesol, geraniol, and perillyl alcohol against transplanted PC-1 hamster pancreatic adenocarcinomas. Syrian Golden hamsters fed geraniol or farnesol at 20 g/kg diet exhibited complete inhibition of PC-1 pancreatic tumor growth. Both farnesol and geraniol were more potent than perillyl alcohol, which inhibited tumor growth by 50% at 40 g/kg diet. Neither body weights nor plasma cholesterol levels of animals consuming isoprenoid diets were significantly different from those of pair-fed controls. Thus, farnesol, geraniol, and perillyl alcohol suppress pancreatic tumor growth without significantly affecting blood cholesterol levels. These dietary isoprenoids warrant further investigation for pancreatic cancer prevention and treatment.

Treatment of chronic gastric ulcer with carbenoxolone and gefarnate: a comparative trial

In 68 patients with chronic gastric ulcer treated in an outpatient clinical trial with either carbenoxolone or gefarnate ulcer healing was consistently greater during carbenoxolone treatment, even though the dose of gefarnate was ultimately increased to four times that recommended. One-third of the patients receiving carbenoxolone gained weight rapidly and unexpectedly, and were given diuretic treatment, compared with two of the 35 patients receiving gefarnate, neither of whom developed clinical oedema.