Celecoxib reduces the effects of acute and chronic UVB exposure in mice treated with therapeutically relevant immunosuppressive drugs

Potential inhibition of 12-O-tetradecanoylphorbol-13-acetate-induced inflammation, hyperproliferation, and hyperplasiogenic responses by celecoxib in mouse skin

PURPOSE

Skin exposure to noxious agents leads to cutaneous lesion marked by an increase in inflammation, cellular proliferation, and hyperplasiogenic reactions. Studies have demonstrated that these damages breach the skin integrity resulting in the aetiology of various cutaneous disorders like atopic dermatitis, eczema, psoriasis, and development of non-melanoma skin cancer. Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, is an effective treatment for a variety of inflammatory diseases. Its importance in the therapy of skin problems, however, remains under appreciated.

METHODS

We tested efficacy of topically applied celecoxib in mitigating skin inflammation, cellular proliferation, and hyperplasia induced by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) in Swiss albino mice.

RESULTS

Celecoxib (5 and 10 μmol) markedly reduced TPA (10 nmol) induced prostaglandin E2 (PGE2) production, oedema formation, myeloperoxidase (MPO) activity, and levels of pro-inflammatory cytokines such as tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). It also resulted in a considerable decrease in ornithine decarboxylase (ODC) activity and the incorporation of [3H]-thymidine into DNA. In addition, there was a significant reduction in histoarchitectural abnormalities such as epidermal thickness, number of epidermal cell layers, neutrophil infiltration, intercellular oedema, and vasodilation.

CONCLUSION

Our results demonstrate that topical celecoxib can reduce the inflammation, hyperproliferation, and hyperplasiogenic events of skin insults suggesting that it may prove to be a valuable management option for cutaneous lesion and associated illnesses such as atopic dermatitis, eczema, and psoriasis, as well as the emergence of non-melanoma cancer.

Photo-Protective and Anti-Inflammatory Effects of Antidesma thwaitesianum Müll. Arg. Fruit Extract against UVB-Induced Keratinocyte Cell Damage

The main cause of most skin cancers is damage from UVB from sunlight, which penetrate the skin surface and induce inflammation. For this reason, this study aims to identify natural products with photo-protection properties and their mode of action by using the UVB-irradiated HaCaT keratinocyte model. Antidesma thwaitesianum fruit extracts at 25, 50, and 100 µg/mL recovered cell viability following UVB exposure in a dose-dependent manner. Cell survival was associated with the reduction in intracellular ROS and NO. In addition, we showed that the pre-treatment with the fruit extract lowered the phosphorylation level of two MAPK-signaling pathways: p38 MAPKs and JNKs. The resulting lower MAPK activation decreased their downstream pro-inflammatory cascade through COX-2 expression and subsequently reduced the PGE₂ proinflammatory mediator level. The photoprotective effects of the fruit extract were correlated with the presence of polyphenolic compounds, including cyanidin, ferulic acid, caffeic acid, vanillic acid, and protocatechuic acid, which have been previously described as antioxidant and anti-inflammation. Together, we demonstrated that the pre-treatment with the fruit extract had photo-protection by inhibiting oxidative stress and subsequently lowered stress-induced MAPK responses. Therefore, this fresh fruit is worthy of investigation to be utilized as a skincare ingredient for preventing UVB-induced skin damage.

Oral administration of Jumihaidokuto inhibits UVB-induced skin damage and prostaglandin E2 production in HR-1 hairless mice

This study was conducted to investigate whether and how Jumihaidokuto (JHT), a traditional Chinese medicine, prevents UVB-induced skin damage in male HR-1 hairless mice. JHT has been traditionally prescribed for patients presenting skin disorders with redness and swelling, and, in Japan, it is approved for prescription to patients with acute and/or purulent skin disorders, hives, acute eczema, and athlete's foot. Considering the traditional use of JHT, we hypothesized that oral administration of JHT might emerge as an effective strategy to prevent UVB-induced skin damage, such as edema and erythema. Here, we pretreated mice with JHT (1000 mg/kg, p.o.) for 3 weeks and then administered a single dose of UVB irradiation (250 mJ/cm²) on the dorsal skin. UVB irradiation increased the erythema index and transepidermal water loss (TEWL) and decreased the skin water content in the epidermis at 72 h post-irradiation. JHT treatment inhibited the increase of TEWL and the loss of water content in the epidermis, but not the elevation of the erythema index. Moreover, administration of JHT suppressed UVB-induced epidermal hyperplasia by blocking the proliferation of keratinocytes and also inhibited irradiation-triggered reduction of collagen fibers and infiltration of immune cells into the dermis. Lastly, administration of JHT suppressed UVB-induced production of proinflammatory mediators, such as prostaglandin E2 and interleukin-1β. These results suggest that JHT prevents UVB-induced skin damage and that the underlying mechanism involves the inhibition of proinflammatory mediators.

Cutaneous Application of Celecoxib for Inflammatory and Cancer Diseases

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) and particularly selective cyclooxygenase-2 (COX-2) inhibitors such as celecoxib (Cxb) are considered promising cancer chemopreventive for colon, breast, prostate, lung, and skin cancers. However, the clinical application to the prevention is limited by concerns about safety, potential to serious toxicity (mainly for healthy individuals), efficacy and optimal treatment regimen. Cxb exhibits advantages as potent antiinflammatory and gastrointestinal tolerance compared with conventional NSAID's. Recent researches suggest that dermatological formulations of Cxb are more suitable than oral administration in the treatment of cutaneous disease, including skin cancer. To date, optimism has been growing regarding the exploration of the topical application of Cxb (in the prevention of skin cancers and treatment of cutaneous inflammation) or transdermal route reducing risks of systemic side effects.

OBJECTIVE

This paper briefly summarizes our current knowledge of the development of the cutaneous formulations or delivery systems for Cxb as anti-inflammatory drug (for topical or transdermal application) as well its chemopreventive properties focused on skin cancer.

CONCLUSION

New perspectives emerge from the growing knowledge, bringing innovative techniques combining the action of Cxb with other substances or agents which act in a different way, but complementary, increasing the efficacy and minimizing toxicity.

Copaiba oil enhances in vitro/in vivo cutaneous permeability and in vivo anti-inflammatory effect of celecoxib

OBJECTIVES

The aim of this article was to use copaiba oil (C.O) to improve skin permeability and topical anti-inflammatory activity of celecoxib (Cxb).

METHODS

Formulations containing C.O (1-50%) were associated with Cxb (2%). In vitro skin permeability studies were conducted using porcine ear skin. Histological analysis of the hairless mice skin samples after application of formulations was achieved with the routine haematoxylin/eosin technique. The anti-inflammatory activity was assessed using the AA-induced ear oedema mice model.

KEY FINDINGS

The formulation containing 25% C.O promoted the highest levels of in vitro Cxb permeation through pig ear skin, retention in the stratum corneum (SC) and epidermis/dermis of pig ear skin in vitro (~5-fold) and hairless mice skin in vivo (~2.0-fold), as compared with the control formulation. At 25%, C.O caused SC disorganization and increased cell infiltration and induced angiogenesis without clear signs of skin irritation. The formulation added to 25% C.O as adjuvant inhibited ear oedema and protein extravasation by 77.51 and 89.7%, respectively, and that it was, respectively, 2.0- and 3.4-fold more efficient than the commercial diethylammonium diclofenac cream gel to suppress these inflammatory parameters.

CONCLUSIONS

25% C.O is a potential penetration enhancer for lipophilic drugs like Cxb that can improve cutaneous drug penetration and its anti-inflammatory activity.

Cyanidin-3-O-glucoside inhibits the UVB-induced ROS/COX-2 pathway in HaCaT cells

Ultraviolet (UV) radiation from sunlight, especially UVB (290-320nm), is one of the most important environmental factors that destroys the integrity of the skin and causes epidermal cell apoptosis, potentially even leading to skin cancer. UVB irradiation can cause skin damage by stimulating inflammatory and apoptotic pathways. Anthocyanins are flavonoids that are common in many vegetable foods, and have also demonstrated chemopreventive effects. Cyanidin-3-O-glucoside, as a typical anthocyanin, exhibits anti-inflammatory and anti-oxidant effects. This study aimed to investigate the effects, as well as the underlying mechanisms, of treating UVB-exposed HaCaT cells with Cyanidin-3-O-glucoside. We demonstrated that Cyanidin-3-O-glucoside could effectively prevent the UVB-induced apoptosis of HaCaT cells. This protective effect can be explained by the scavenging of ROS and the suppression of COX-2 expression by interaction with the MAPK and Akt signaling pathways. Furthermore, we used Celecoxib as a positive control, and results showed that Cyanidin-3-O-glucoside was more effective at decreasing EGFR phosphorylation than Celecoxib, which translated into a stronger inhibitory effect against the downstream elements p38, ERK, and JNK. Taken together, these results indicate that Cyanidin-3-O-glucoside can protect HaCaT cells against UVB radiation, which could provide a basis for the development of a potent nutritional therapy for UVB-induced skin disorders.

Tomatoes protect against development of UV-induced keratinocyte carcinoma via metabolomic alterations

Prolonged tomato consumption can mitigate ultraviolet (UV) light induced sunburn via unknown mechanisms. Dietary carotenoids distributed to skin are hypothesized to protect skin against UV-induced damage, although other phytochemicals may play a role. We hypothesize that tomato consumption would protect against skin cancer. SKH-1 hairless and immunocompetent mice (n = 180) were fed AIN-93G or AIN-93G + 10% tangerine or red tomato powder for 35 weeks. From weeks 11-20, mice (n = 120) were exposed to 2240 J/m² UV-B light, 3x/week, and tumors were tracked weekly. Control mice were fed the same diets but not exposed to UV. Tumor number was significantly lower in male mice consuming red tomato diets (1.73 ± 0.50, P = 0.015) or pooled tomato diets (2.03 ± 0.45, P = 0.017) compared to controls (4.04 ± 0.65). Carotenoid levels in plasma and skin were quantitated, with total lycopene higher in skin of tangerine fed animals despite a lower dose. Metabolomic analyses elucidated compounds derived from tomato glycoalkaloids (including tomatidine and hydroxylated-tomatidine) as significantly different metabolites in skin after tomato exposure. Here, we describe that tomato consumption can modulate risk for keratinocyte carcinomas; however, the role of the newly identified specific phytochemicals possibly responsible for this action require further investigation.

Comparison of the acute ultraviolet photoresponse in congenic albino hairless C57BL/6J mice relative to outbred SKH1 hairless mice

Hairless albino Crl:SKH1-Hr(hr) mice are commonly utilized for studies in which hair or pigmentation would introduce an impediment to observational studies. Being an outbred strain, the SKH1 model suffers from key limitations that are not seen with congenic mouse strains. Inbred and congenic C57BL/6J mice are commonly utilized for modified genetic mouse models. We compare the acute UV-induced photoresponse between outbred SKH1 mice and an immune competent, hairless, albino C57BL/6J congenic mouse line [B6.Cg-Tyr(c-2J) Hr(hr) /J]. Histologically, B6.Cg-Tyr(c-2J) Hr(hr) /J skin is indistinguishable from that of SKH1 mice. The skin of both SKH1 and B6.Cg-Tyr(c-2J) Hr(hr) /J mice exhibited a reduction in hypodermal adipose tissue, the presence of utricles and dermal cystic structures, the presence of dermal granulomas and epidermal thickening. In response to a single 1500 J/m(2) ultraviolet B dose, the oedema and apoptotic responses were equivalent in both mouse strains. However, B6.Cg-Tyr(c-2J) Hr(hr) /J mice exhibited a more robust delayed sunburn reaction, with an increase in epidermal erosion, scab formation and myeloperoxidase activity relative to SKH1 mice. Compared with SKH1 mice, B6.Cg-Tyr(c-2J) Hr(hr) /J also exhibited an aberrant proliferative response to this single UV exposure. Epidermal Ki67 immunopositivity was significantly suppressed in B6.Cg-Tyr(c-2J) Hr(hr) /J mice at 24 h post-UV. A smaller non-significant reduction in Ki67 labelling was observed in SKH1 mice. Finally, at 72 h post-UV, SKH1 mice, but not B6.Cg-Tyr(c-2J) Hr(hr) /J mice, exhibited a significant increase in Ki67 immunolabelling relative to non-irradiated controls. Thus, B6.Cg-Tyr(c-2J) Hr(hr) /J mice are suitable for photobiology experiments.

Rapamycin combined with celecoxib enhanced antitumor effects of mono treatment on chronic myelogenous leukemia cells through downregulating mTOR pathway

Chronic myelogenous leukemia is a neoplasm of myeloid progenitor cells. We recently found that rapamycin could induce G0/G1 phase arrest and apoptosis and inhibit proliferation of K562 cells through inhibiting mammalian target of rapamycin (mTOR) pathway. However, whether rapamycin has synergistic effects with other drugs in chronic myelogenous leukemia (CML) therapies remain unclear. Therefore, we examined the effect of rapamycin combined with celecoxib on K562 cells in vitro. The survival rates showed a significant decrease in rapamycin + celecoxib treatment group. The combination treatment also increased the G0/G1 phase cells as compared to rapamycin or celecoxib treatment alone (P < 0.05), accompanied with the decreased population of S phase cells. Meanwhile, the rate of apoptosis was 15.87 ± 2.21 % in rapamycin + celecoxib treatment group, significantly higher than that in mono treatment group (P < 0.05). Western blot and reverse transcription PCR (RT-PCR) analysis showed that the expressions of mTOR, 4E-BP1, and p70S6K were all significantly decreased in K562 cells after rapamycin + celecoxib treatment (P < 0.05). In conclusion, rapamycin combined with celecoxib could induce cell cycle arrest and apoptosis and decrease the expressions of mTOR, 4E-BP1, and p70S6K. It suggested that the combination could enhance the antitumor effects of mono treatment on CML cells through downregulating mTOR pathway.

Prostaglandin E2 Promotes UV radiation-induced immune suppression through DNA hypermethylation

Exposure of mice to UV radiation results in suppression of the contact hypersensitivity (CHS) response. Here, we report that the UV-induced suppression of CHS is associated with increases in the levels of cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and PGE2 receptors in the exposed skin. UV radiation-induced suppression of CHS was inhibited by topical treatment of the skin with celecoxib or indomethacin (inhibitors of COX-2) or AH6809 (an EP2 antagonist). Moreover, mice deficient in COX-2 were found to be resistant to UV-induced suppression of CHS. The exposure of wild-typemice to UVB radiation resulted in DNA hypermethylation, increased DNA methyltransferase (Dnmt) activity, and elevated levels of Dnmt1, Dnmt3a, and Dnmt3b proteins in the skin, and these responses were downregulated on topical treatment of the site of exposure after irradiation with indomethacin or EP2 antagonist. Topical treatment of UVB-exposed COX-2-deficient mice with PGE2 enhanced the UVB-induced suppression of CHS as well as global DNA methylation and elevated the levels of Dnmt activity and Dnmt proteins in the skin. Intraperitoneal injection of 5-aza-2'-deoxycytidine (5-Aza-dc), a DNA demethylating agent, restored the CHS response to 2,4-dinitrofluorobenzene in UVB-exposed skin and this was associated with the reduction in global DNA methylation and Dnmt activity and reduced levels of Dnmt proteins. Furthermore, treatment with 5-Aza-dc reversed the effect of PGE2 on UV-induced suppression of CHS in COX-2-deficient mice. These findings reveal a previously unrecognized role for PGE2 in the promotion of UVB-induced immunosuppression and indicate that it is mediated through PGE2 regulation of DNA methylation.

The prostaglandin E2 receptor, EP2, regulates survivin expression via an EGFR/STAT3 pathway in UVB-exposed mouse skin

We previously reported that cycloogenase (COX)-2-generated prostaglandin E2 (PGE2) had anti-apoptotic effects in UVB-exposed mouse skin that involved EP2-mediated signaling (Chun et al., Cancer Res. 2007; 67: 2015). Because survivin is a regulator of cell survival, the possible involvement of COX-2 and EP2 in survivin expression following UVB exposure of mouse skin was investigated. In wild type mice, UVB exposure time-dependently increased the levels of survivin and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3), a transcription factor that regulates survivin expression; and COX-2- or EP2-deficiency significantly reduced their induction. Topical application of the COX-2 inhibitor, celecoxib, also reduced UVB-induced survivin levels. To further investigate the roles of PGE2 and EP2 in the regulation of survivin, indomethacin was used to inhibit UVB-induced endogenous PG production. UVB-induced survivin levels were reduced by indomethacin, and PGE2 and the EP2 agonist, butaprost, partially restored survivin levels. The epidermal growth factor receptor (EGFR) is a downstream effector of EP2 and EGFR inhibition (AG1478) significantly reduced UVB activation of STAT3 and survivin levels. UVB-induced epidermal apoptosis in COX-2-/- mice was reduced by butaprost and EGFR inhibition blocked butaprost’s protective effects. Furthermore, butaprost in the absence of UVB exposure time-dependently increased p-EGFR, p-STAT3, and survivin levels in naïve mouse skin, whereas the EP4 agonist, PGE1 alcohol, did not significantly increase p-STAT3 or survivin levels. These data suggest that COX-2-generated PGE2 regulates survivin expression in mouse skin, in part, via an EP2-mediated EGFR/STAT3 pathway. Therefore, targeting the EP2/survivin pathway may provide a strategy for the chemoprevention/chemotherapy of skin cancer.