3'-Hydroxypterostilbene Inhibits 7,12-Dimethylbenz[a]anthracene (DMBA)/12-O-Tetradecanoylphorbol-13-Acetate (TPA)-Induced Mouse Skin Carcinogenesis.

BACKGROUND: A natural pterostilbene analogue isolated from the herb Sphaerophysa salsula, 3'-hydroxypterostilbene (HPSB), exhibits antiproliferative activity in several cancer cell lines; however, the inhibitory effects of HPSB on skin carcinogenesis remains unclear. PURPOSE: The aim of this study was to evaluate the inhibitory effects of HPSB on two-stage skin carcinogenesis in mice and its potential mechanism. STUDY DESIGN AND METHODS: This study investigated the anti-inflammatory and anti-tumor effects of HPSB in the 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated acute skin inflammation and 7,12-dimethylbenz[a]anthracene (DMBA)/TPA-induced two-stage skin carcinogenesis model. In addition, the effects of HPSB on the modulation of the phase I and phase II metabolizing enzymes in the DMBA-induced HaCaT cell model were investigated. RESULTS: The results provide evidence that topical treatment with HPSB significantly inhibits TPA-induced epidermal hyperplasia and leukocyte infiltration through the down-regulation of cyclooxygenase-2 (COX-2), matrix metalloprotein-9 (MMP-9), and ornithine decarboxylase (ODC) protein expression in mouse skin. Furthermore, HPSB suppresses DMBA/TPA-induced skin tumor incidence and multiplicity via the inhibition of proliferating cell nuclear antigen (PCNA), Cyclin B1 and cyclin-dependent kinase 1 (CDK1) expression in the two-stage skin carcinogenesis model. In addition, pretreatment with HPSB markedly reduces DMBA-induced cytochrome P450 1A1 (CYP1A1) and cytochrome P450 1B1 (CYP1B1) gene expression in human keratinocytes; however, HPSB does not significantly affect the gene expression of the phase II enzymes. CONCLUSION: This is the first study to show that topical treatment with HPSB prevents mouse skin tumorigenesis. Overall, our study suggests that natural HPSB may serve as a novel chemopreventive agent capable of preventing carcinogen activation and inflammation-associated tumorigenesis.

Evaluation of a Comprehensive Skin Toxicity Program for Patients Treated With Epidermal Growth Factor Receptor Inhibitors at a Cancer Treatment Center.

Importance: Up to 90% of patients treated with an epidermal growth factor receptor inhibitor (EGFRi) experience cutaneous toxic effects that are negatively associated with quality of life and lead to treatment interruptions. The Skin Toxicity Evaluation Protocol With Panitumumab trial found reduced incidence of skin toxicity and quality of life impairment with preemptive use of doxycycline hyclate, topical corticosteroids, moisturizers, and sunscreen, demonstrating the benefit of prophylactic treatment for skin toxicity. Objective: To evaluate the association of a comprehensive skin toxicity program with adherence to prophylaxis guidelines for the prevention of EGFRi-associated cutaneous toxic effects. Design, Setting, and Participants: A retrospective cohort study was conducted of all adult patients receiving at least 1 dose of cetuximab at the Dana-Farber Cancer Institute in the calendar year 2012 (2 years after publication of the Skin Toxicity Evaluation Protocol With Panitumumab) or the calendar year 2017 (2 years after full implementation of the Skin Toxicities from Anticancer Therapies program). Main Outcomes and Measures: Primary outcomes were rate of preemptive rash treatment and selection of preemptive agents. Secondary outcomes were incidence of rash, rates of rescue treatments, rates of cetuximab dose changes or interruptions, and overall survival at 2 years. Results: There were 118 patients (85 men; median age, 62.4 years [range, 23.5-91.7 years]) treated with cetuximab in 2012 and 90 patients (70 men; median age, 62.5 years [range, 30.7-90.5 years]) treated with cetuximab in 2017; 11 patients (9%) in 2012 and 31 patients (34%) in 2017 were treated at Dana-Farber Cancer Institute affiliate sites. At cetuximab treatment initiation, 29 patients (25%) in 2012 and 42 patients (47%) in 2017 were prophylactically treated for skin toxicity (P < .001). From 2012 to 2017, preemptive tetracycline use (13 of 29 [45%] to 30 of 42 [71%]; P = .02) and topical corticosteroid use (2 of 29 [7%] to 24 of 42 [57%]; P < .001) increased and topical antibiotic use (23 of 29 [79%] to 18 of 42 [43%]; P = .002) decreased. There was no significant difference in incidence of rash by prophylaxis status. Patients prescribed prophylactic treatment were 94% less likely to require a first rescue treatment for rash (adjusted odds ratio, 0.06; 95% CI, 0.02-0.16; P < .001), 74% less likely to require a second rescue treatment for rash (adjusted odds ratio, 0.26; 95% CI, 0.08-0.83; P = .02), and 79% less likely to experience a cetuximab dose change or interruption (adjusted odds ratio, 0.21; 95% CI, 0.06-0.81; P = .02) than patients not prescribed prophylactic treatment, adjusting for treatment site and year. Conclusions and Relevance: Dermatologists can add value to oncology care by raising awareness of appropriate treatment options and increasing adherence to evidence-based prophylaxis protocols for EGFRi-associated rash, which is associated with decreased interventions and toxicity-associated chemotherapy interruptions.

A simple in chemico method for testing skin sensitizing potential of chemicals using small endogenous molecules.

Among many of the validated methods for testing skin sensitization, direct peptide reactivity assay (DPRA) employs no cells or animals. Although no immune cells are involved in this assay, it reliably predicts the skin sensitization potential of a chemical in chemico. Herein, a new method was developed using endogenous small-molecular-weight compounds, cysteamine and glutathione, rather than synthetic peptides, to differentiate skin sensitizers from non-sensitizers with an accuracy as high as DPRA. The percent depletion of cysteamine and glutathione by test chemicals was measured by an HPLC equipped with a PDA detector. To detect small-size molecules, such as cysteamine and glutathione, a derivatization by 4-(4-dimethylaminophenylazo) benzenesulfonyl chloride (DABS-Cl) was employed prior to the HPLC analysis. Following test method optimization, a cut-off criterion of 7.14% depletion was applied to differentiate skin sensitizers from non-sensitizers in combination of the ratio of 1:25 for cysteamine:test chemical with 1:50 for glutathione:test chemical for the best predictivity among various single or combination conditions. Although overlapping HPLC peaks could not be fully resolved for some test chemicals, high levels of sensitivity (100.0%), specificity (81.8%), and accuracy (93.3%) were obtained for 30 chemicals tested, which were comparable or better than those achieved with DPRA.

BAY 11-7082 inhibits the NF-κB and NLRP3 inflammasome pathways and protects against IMQ-induced psoriasis.

BAY 11-7082 antagonizes I-κB kinase-ß preventing nuclear translocation of nuclear factor-κB (NF-κB); it also inhibits NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation. NF-κB is involved in psoriasis, whereas the role of NLRP3 is controversial. We investigated BAY 11-7082 effects in an experimental model of psoriasis-like dermatitis. Psoriasis-like lesions were induced by a topical application of imiquimod (IMQ) cream (62.5 mg/day) on the shaved back skin of C57BL/6 and NLRP3 knockout (KO) mice for 7 consecutive days. Sham psoriasis animals were challenged with Vaseline cream. Sham and IMQ animals were randomized to receive BAY 11-7082 (20 mg/kg/i.p.) or its vehicle (100 µl/i.p of 0.9% NaCl). Skin of IMQ animals developed erythema, scales, thickening and epidermal acanthosis. IMQ skin samples showed increased expression of pNF-κB and NLRP3 activation. BAY 11-7082 blunted epidermal thickness, acanthosis and inflammatory infiltrate. BAY 11-7082 reduced pNF-κB, NLRP3, tumour necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1ß expression, blunted the phosphorylation of signal transducer and activators of transcription 3 (STAT3) and decreased IL-23 levels. In addition, BAY 11-7082 reawakened the apoptotic machinery. NLRP3 KO animals showed a reduced total histological score but persistent mild acanthosis, dermal thickness and expression of pNF-κB and pSTAT3, following IMQ application. Our data suggest that BAY 11-7082 might represent an interesting approach for the management of psoriasis-like dermatitis depending on the dual inhibition of NF-κB and NLRP3.

Peginterferon alfa related psoriasis in a patient with acute hepatitis C and review of the literature.

The Interferon (IFN) which is the standard treatment for Hepatitis C, may cause a lot of side effects including dermatological anomalies. This paper presents a psoriasis case which occurred in relation with the treatment of acute hepatitis C (AHC) with peginterferon alfa (peg-IFN-α). A 60-year-old male patient came to the hospital with symptoms of high liver enzymes. The patient with history of a recent operation showed anti-HCV(+), HCVRNA 3.5 million IU/mL and HCV genotype 1b in the tests. Without any other etiological factors found in the patient, we started a treatment of peg-IFNα-2b with the diagnosis of AHC. After 3 weeks, psoriatic plaques were observed in various parts of the body. Antiviral treatment of the patient was concluded within 6 months. His psoriasis treatment initially commenced with local agents followed by phototherapy. Permanent viral response was seen in the patient and his lesions recovered rapidly after the antipsoriatic and antiviral treatment. Psoriasis and other autoimmune diseases should be considered even though they are encountered rarely,and the patients should be informed of the possible risks before planning treatment with peg-IFN-α.

Cutaneous side effects of combined therapy with sorafenib and pegylated interferon alpha-2b in metastatic melanoma (phase II DeCOG trial).

BACKGROUND AND OBJECTIVES: During a clinical study with combined therapy of sorafenib and pegylated interferon alpha-2b (SoraPeg study) of the German Dermatologic Oncology Group (ADO/DeCOG), multiple and severe cutaneous side effects were observed. This study sought to analyze these cutaneous side effects, particularly because future studies with combinations of interferon alpha and targeted therapies are planned. PATIENTS AND METHODS: In a multicenter phase-II-DeCOG study (NCT00623402) in 10 dermato-oncology centers, 55 patients with metastatic melanoma received a combination of sorafenib (2 x 400 mg/day orally) and pegylated interferon alpha-2b (3 µg/kg body weight 1 x/week subcutaneously). All cutaneous side effects were documented. RESULTS: Forty-one patients (74.5 %) developed cutaneous side effects, particularly exanthems (51.2 %), hand-foot syndrome (36.5 %), alopecia (36.5 %) and pruritus (24.4 %). Due to the cutaneous side effects, dose reductions were required in 10 patients, interruption of therapy in 10 cases and permanent discontinuation of therapy and in one patient with extensive follicular-cystic lesions. Exanthems were seen more frequently in women (76.2 %) than in men (23.8 %). The occurrence of cutaneous side effects was not correlated with clinical outcome or prognosis. CONCLUSIONS: The combination of sorafenib/pegylated interferon alpha-2b caused more cutaneous side effects than have been reported for single agents. Despite intensive dermatologic management of the cutaneous side effects 24 % of patients required a dose modification.

Efficacy and tolerability of topical 0.2% Myrtacine® and 4% vitamin PP for prevention and treatment of retinoid dermatitis in patients with mild to moderate acne.

AIM: The aim of the present study was to evaluate the efficacy and tolerability of an emulsion of 0.2% Myrtacine® and 4% vitamin PP, compared with a simple emollient cream, in the treatment of retinoid dermatitis in patients with mild-to-moderate acne. METHODS: This was a prospective, multicenter, open-label, non-randomised, parallel-group study. Patients (age 12-49 years; skin phototype I-IV) with mild-to-moderate acne, who were treated with a topical retinoid for at least one month and had developed skin irritation were assigned to one of the two following treatments: 0.2% Myrtacine® and 4% vitamin PP (N.=116) or a simple emollient cream (N.=48). Both treatments were administered twice daily, 1-1.5 hours after the application of the topical retinoid. Study endpoints were improvement in signs and symptoms of retinoid dermatitis, global efficacy, reduction in acne severity, overall clinical outcome, patient satisfaction and tolerability. RESULTS: At day 28, compared with the simple emollient cream, 0.2% Myrtacine® and 4% vitamin PP significantly decreased signs (erythema, dryness/scaling, oedema, and roughness) and symptoms (itching, stinging, burning sensation and discomfort) of retinoid dermatitis (P<0.01). In addition, compared with the simple emollient cream, 0.2% Myrtacine® and 4% vitamin PP decreased acne severity in a significantly greater proportion of patients (P=0.023) and was associated with a better clinical outcome (mild, intermediate, clinically relevant or global improvement; P<0.001). 0.2% Myrtacine® and 4% vitamin PP was also associated with greater patient satisfaction and was better tolerated than the simple emollient cream. CONCLUSION: 0.2% Myrtacine® and 4% vitamin PP was effective and well tolerated in the treatment of retinoid dermatitis in patients with mild-to-moderate acne and significantly improved acne severity and overall clinical outcome.

[Persistent swelling after flushing of an abscess with Octenisept®]. / Persistierende Schwellung nach Spülung eines Abszesses mit Octenisept®.

We report the case of a long-lasting cutaneous side effect after inappropriate use of Octenisept® solution (containing octenidine and phenoxyethanol). Following lavage of an abscess in the inguinal region, a painful erythematous induration mimicking cellulitis persisted for several months. Manual lymphatic drainage considerably improved the symptoms. Octenisept® shows considerable tissue toxicity in vivo including - but not restricted to - blood vessel damage. Deterioration of endothelial cells followed by oedema and continued tissue damage can be seen histologically. Despite the fact that there is a circular letter issued by the manufacturer as well as a boxed warning on the bottles, the awareness to avoid this misuse of Octenisept® is still lacking.

Review article: the management of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma is the leading cause of death in cirrhosis. A majority of patients present at an advanced stage with poor prognosis. AIM: To review the current screening, diagnosis and management strategies involved in hepatocellular carcinoma. METHODS: A literature search was performed using PubMed for publications with a predetermined search string to identify relevant studies. RESULTS: Hepatocellular carcinoma is dramatically increasing in incidence that is mostly attributed to chronic hepatitis C and non-alcoholic fatty liver disease/non-alcoholic steatohepatitis and its clinical phenotype diabetes and obesity. Cirrhosis is the major predisposing risk factor and its presence necessitates close surveillance for hepatocellular carcinoma with serial imaging studies. Hepatocellular carcinoma can be diagnosed by its unique radiological behaviour of arterial enhancement and washout on delayed images. The Barcelona Clinic Liver Cancer staging classification system is a clinically useful algorithm for the management of patients with hepatocellular carcinoma. The simultaneous presence of cirrhosis in the patients complicates their management and monitoring for cirrhosis-related complications is important. CONCLUSIONS: Early diagnosis and definitive treatment remains the key to long-term outcome. A multidisciplinary approach is critical to the successful management of hepatocellular carcinoma. Studies combining sorafenib with locoregional or other targeted molecular therapies are likely to improve responses and outcome.

The use of cod liver oil by patients receiving pegylated liposomal doxorubicin is associated with a lack of severe palmar-plantar erythrodysesthesia.

Pegylated liposomal doxorubicin (PLD) is an effective and tolerable agent in the treatment of recurrent and refractory ovarian carcinoma. One of the most common dose-limiting toxicities of PLD is palmar-plantar erythrodysesthesia (PPE). We report a retrospective review of patients who took cod liver oil (CLO) while being treated with PLD at Roswell Park Cancer Institute. None of the patients required dose reduction, treatment interruption or discontinuation secondary to skin toxicity. No patient experienced grade 2 or greater PPE. The mechanism for the development of PLD-induced PPE is unknown. CLO may possibly mitigate it via decreased extravasation of PLD and/or by a blunting of the local inflammatory response. The effects of CLO should be further evaluated in a prospective, randomized trial, and attempts to elucidate the mechanism by which CLO may exert its effects should be pursued.

Effect of folic or folinic acid supplementation on methotrexate-associated safety and efficacy in inflammatory disease: a systematic review.

BACKGROUND: Methotrexate is a folic acid antagonist widely used for the treatment of inflammatory disorders for more than 50 years. Methotrexate is a standard systemic therapy for severe psoriasis and rheumatoid arthritis. Folic acid supplementation has been advocated to limit the toxicity of methotrexate on blood cells, gastrointestinal tract and liver. However, there is still controversy regarding the usefulness of folic acid supplementation. OBJECTIVES: We sought to assess the evidence for the efficacy of folic acid supplementation in patients treated with methotrexate for inflammatory diseases. We also investigated whether folic acid supplementation may decrease the efficacy of methotrexate. METHODS: Cochrane and MEDLINE databases were systematically searched. Randomized controlled trials in patients treated with methotrexate for rheumatoid arthritis or psoriasis with or without arthritis were included. Study selection, assessment of methodological quality, data extraction and analysis were carried out by two independent researchers. We selected double-blind randomized placebo-controlled trials. Analysis was performed for each subgroup of side-effects: gastrointestinal, mucocutaneous, haematological and hepatic. RESULTS: Six randomized controlled trials met the inclusion criteria, with a total sample of 648 patients. There were 257 patients in the placebo group, 198 patients treated with folic acid, and 193 patients treated with folinic acid. The statistical analysis showed a significant reduction of 35.8% of hepatic side-effects induced by methotrexate for patients with supplementation with folic or folinic acid (95% confidence interval -0.467 to -0.248). There was no statistical difference for mucocutaneous and gastrointestinal side-effects although there was a trend in favour of supplementation. The effect of supplementation on haematological side-effects could not be assessed accurately due to a low incidence of these events in the population studied. We were unable to analyse the effect of supplementation on the effectiveness of methotrexate, as markers of activity used in each study were not comparable. CONCLUSIONS: Supplementation with folic acid is an effective measure to reduce hepatic adverse effects associated with methotrexate treatment. There is no difference between folinic acid and folic acid, but the lower cost of the latter promotes its use.

[Clinical analysis on 162 cases of drug eruption induced by Chinese patent medicine].

OBJECTIVE: To analyze the pathogenesis and characteristics of drug eruption induced by Chinese patent medicine for providing some referential materials on prevention and treatment of drug eruption. METHODS: Clinical data of 162 patients suffered from drug eruption were analyzed retrospectively. RESULTS: Most the drug eruption (161 times/case, accounting for 99.4%) belonged to the mild type; injection was the dominating dosage-form for inducing drug eruptions (87 times/case, 53.7%); most of the cases occurred when drugs were used in combination (106 times/case, 65.4%); and few of the patients (14 times/case, 8.6%) had drug eruption for the first time. CONCLUSION: Prevention of drug eruption could be realized by way of learning more relevant knowledge, cautiousl accepting the Chinese herbal injection, avoiding drug combination, as well as inquiry for the history of drug application of patients in detail.

Inhibition of chronic skin inflammation by topical anti-inflammatory flavonoid preparation, Ato Formula.

Flavonoids are known as natural anti-inflammatory agents. In this investigation, an anti-inflammatory potential of new topical preparation (SK Ato Formula) containing flavonoid mixtures from Scutellaria baicalensis Georgi roots and Ginkgo biloba L. leaves with an extract of Gentiana scabra Bunge roots was evaluated in an animal model of chronic skin inflammation. Multiple 12-O-tetradecanoylphorbol-13-acetate treatments for 7 consecutive days on ICR mouse ear provoked a chronic type of skin inflammation: dermal edema, epidermal hyperplasia and infiltration of inflammatory cells. When topically applied in this model, this new formulation (5-20 microL/ear/treatment) reduced these responses. Furthermore, it inhibited prostaglandin E2 generation (17.1-33.3%) and suppressed the expression of proinflammatory genes, cyclooxygenase-2 and interleulin-1beta in the skin lesion. Although the potency of inhibition was lower than that of prednisolone, all these results suggest that Ato Formula may be beneficial for treating chronic skin inflammatory disorders such as atopic dermatitis.

Anti-allergic effects of Lycopus lucidus on mast cell-mediated allergy model.

The current study characterizes the mechanism by which the aqueous extract of Lycopus lucidus Turcz. (Labiatae) (LAE) decreases mast cell-mediated immediate-type allergic reaction. The immediate-type allergic reaction is involved in many allergic diseases such as asthma and allergic rhinitis. LAE has been used as a traditional medicine in Korea and is known to have an anti-inflammatory effect. However, its specific mechanism of action is still unknown. LAE was anally administered to mice for high and fast absorption. LAE inhibited compound 48/80-induced systemic reactions in mice. LAE decreased the local allergic reaction, passive cutaneous anaphylaxis, activated by anti-dinitrophenyl (DNP) IgE antibody. LAE dose-dependently reduced histamine release from rat peritoneal mast cells activated by compound 48/80 or anti-DNP IgE. Furthermore, LAE decreased the secretion of TNF-alpha and IL-6 in phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-stimulated human mast cells. The inhibitory effect of LAE on the pro-inflammatory cytokine was p38 mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-kappaB) dependent. LAE attenuated PMA plus A23187-induced degradation of IkappaBalpha and nuclear translocation of NF-kappaB, and specifically blocked activation of p38 MAPK, but not that of c-jun N-terminal kinase and extracellular signal-regulated kinase. Our findings provide evidence that LAE inhibits mast cell-derived immediate-type allergic reactions and involvement of pro-inflammatory cytokines, p38 MAPK, and NF-kappaB in these effects.

Oral administration of royal jelly inhibits the development of atopic dermatitis-like skin lesions in NC/Nga mice.

We have shown previously that in addition to IL-4, IL-5 and IL-10, antigen-specific interferon-gamma (IFN-gamma) production by spleen cells from ovalbumin (OVA)/Alum-immunized mice is inhibited by the administration of royal jelly (RJ). Since it has been shown that both Th1 and Th2 cytokines play pathogenic roles in the generation of atopic dermatitis (AD), we have examined whether RJ suppresses the development of AD-like skin lesions in NC/Nga mice induced by repeated application of picryl chloride (PiCl) under specific pathogen-free (SPF) conditions. Oral administration of RJ to the PiCl-treated NC/Nga mice inhibited the development of AD-like skin lesions in these mice as exemplified by the significant decrease in the total skin severity scores and the decrease in hypertrophy, hyperkeratosis, and infiltration of the epidermis and corium by inflammatory cells. IFN-gamma production by spleen cells from PiCl-treated NC/Nga mice in response to TNP-KLH was partially but significantly inhibited by the oral administration of RJ, while IFN-gamma production by Con A-stimulated spleen cells was not affected. Since inducible nitric oxide (NO) synthase (iNOS)-derived NO has been suggested as an important immunoregulatory mediator in inflammatory autoimmune diseases, we have also examined the expression of iNOS in the dorsal skin lesions of PiCl-treated NC/Nga mice. Interestingly, the expression of iNOS was significantly increased in the skin lesions of RJ-administered mice compared with those of control PBS-administered mice. Thus, our results suggest that RJ suppresses the development of AD-like skin lesions in PiCl-treated NC/Nga mice, possibly by a combination of down-regulating TNP-specific IFN-gamma production and up-regulating iNOS expression.

Low-dose dithranol treatment and tape stripping induce tolerance to dithranol in a mouse ear oedema model.

BACKGROUND: It is well known from clinical practice that repeated treatment with dithranol leads to the development of tolerance. OBJECTIVES: To investigate the characteristics and mechanism of such dithranol tolerance. METHODS: The mouse ear was pretreated with a low dose of dithranol or croton oil or, in previously sensitized animals, with dinitrofluorobenzene (DNFB). Twenty-four hours later irritant dermatitis was elicited by painting the mouse ear with a high dose of dithranol, croton oil or DNFB, and the dermatitis was characterized by measurement of ear thickness. RESULTS: Low-dose dithranol significantly suppressed dithranol-induced oedema, whereas it had no effect on croton oil- or DNFB-induced dermatitis, suggesting that dithranol-induced tolerance is specific. Tolerance to dithranol could not be induced by pretreatment of the mouse ear with a low dose of croton oil or DNFB. Mild tape stripping of the mouse ear also inhibited the inflammatory effect of dithranol applied 24 h later. Superoxide dismutase treatment abolished the tolerance-inducing effect of low-dose dithranol or stripping. CONCLUSIONS: These results suggest that superoxide anion radicals are involved not only in the inflammatory effect of dithranol, but also in the induction of tolerance.

Inhibitory effect of citrus nobiletin on phorbol ester-induced skin inflammation, oxidative stress, and tumor promotion in mice.

The intake of citrus fruits has been suggested as a way to prevent the development of some types of human cancer. Nitric oxide (NO) is closely associated with the processes of epithelial carcinogenesis. We attempted a search for NO generation inhibitors in Citrus unshiu. The active constituent was traced by an activity-guiding separation. NO and superoxide (O2-) generation was induced by a combination of lipopolysaccharide and IFN-gamma in mouse macrophage RAW 264.7 cells, and by 12-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human promyelocyte HL-60, respectively. Expression of inducible NO synthase and cyclooxygenase 2 proteins were detected by Western blotting. The in vivo anti-inflammatory and antitumor promoting activities were evaluated by topical TPA application to ICR mouse skin with measurement of edema formation, epidermal thickness, leukocyte infiltration, hydrogen peroxide production, and the rate of proliferating cell nuclear antigen-stained cells. As a result, nobiletin, a polymethoxyflavonoid, was identified as an inhibitor of both NO and O2- generation. Nobiletin significantly inhibited two distinct stages of skin inflammation induced by double TPA application [first stage priming (leukocyte infiltration) and second stage activation (oxidative insult by leukocytes)] by decreasing the inflammatory parameters. It also suppressed the expression of cyclooxygenase-2 and inducible NO synthase proteins and prostaglandin E2 release. Nobiletin inhibited dimethylbenz[a]anthracene (0.19 micromol)/TPA (1.6 nmol)-induced skin tumor formation at doses of 160 and 320 nmol by reducing the number of tumors per mouse by 61.2% (P < 0.001) and 75.7% (P < 0.001), respectively. The present study suggests that nobiletin is a functionally novel and possible chemopreventive agent in inflammation-associated tumorigenesis.

Phase I trial of alpha-tocopherol effects on 13-cis-retinoic acid toxicity.

BACKGROUND: Retinoids are under intensive study for the treatment and prevention of cancer. Substantial dose-related toxicities of retinoids are a major obstacle to this work. In a recent retrospective analysis of combined 13-cis-retinoic acid (13cRA) and alpha-tocopherol (AT) in myelodysplasia, 13cRA toxicity was reduced significantly and 13cRA activity was enhanced. These results suggested the need for prospective testing of this new combination. This trial tested the hypotheses that At can reduce toxicity of high-dose 13cRA and does not interfere with 13cRA absorption/activity as reflected by reduced 13cRA serum levels. PATIENTS AND METHODS: This was a phase I trial design in which patients received fixed-dose 13cRA (100 mg/m2/d) plus escalating-dose AT (beginning at 800 IU/d, increased 400 IU/d each month until 2000 IU/d). We collected toxicity data every four weeks from self-report forms, clinical examinations and laboratory studies. AT effects on 13cRA toxicity were determined by comparing maximum toxicity at lowest AT dose with that at highest AT dose. We also measured serum levels of both agents every four weeks. RESULTS: Of the 45 patients registered, 36 had cancer (active or prior history), 9 had premalignant lesions. Thirty-nine patients could be evaluated for initial-course toxicity; 31 for final course toxicity. Median time on treatment (all patients) was four months (range, 1-9 months); a total of 223 month-long courses of treatment were given. Eighteen percent of patients (7/39) developed grade 3 or 4 toxicity in the initial course. The rates of increase and decrease in 13cRA toxicity associated with increasing AT doses were similar: 36% decreased (11/31), 32% increased (10/31) (P = 0.84). At did not reduce 13cRA serum levels. After initial increases of mean AT plasma levels (17.9 micrograms/ ml at baseline to 45.4 micrograms/ml after first four-week course), subsequent AT plasma increases (< 2-fold) did not keep pace with increased AT doses (2-3-fold). No major activity occurred in the 21 patients with active refractory cancer. The complete response rate in patients with premalignant head-and-neck or lung lesions was 77.8% (7/9), which included two patients previously refractory to 13cRA alone. CONCLUSION: Although escalating doses of AT did not reduce 13cRA toxicity, the rate of initial-course (including 800 IU/d of AT) high-grade toxicity was substantially lower than that typical of high-dose 13cRA-alone and similar to that typical of low-dose 13cRA-alone. Indeed, a trial of 13cRA-alone followed by 13cRA plus AT may have detected a significant toxicity difference. We did not design such a trial out of ethical concern for known side effects of high-dose 13cRA. The increase in AT serum levels was not proportional with increasing doses of AT, which may explain the lack of a dose-response effect of AT on 13cRA toxicity. Previous trials have established that 13cRA has an approximate 10% complete response rate in oral premalignancy. Our small trial's 77.8% complete response rate in premalignant lesions suggests that AT may enhance 13cRA clinical activity. Future trials of 13cRA plus AT are needed to define this combinations toxicity profile, clinical activity and pharmacokinetics.