Targeting AR-positive breast cancer cells via drug repurposing approach.

Androgen Receptor (AR) is overexpressed in almost all the molecular subtypes of breast cancer. Besides aiding the tumorigenic environment of cancer by abnormal cell proliferation, AR also takes part in promoting cancer signaling pathways, thereby promoting aggressiveness. In this study, AR was selected as the target protein in breast cancer cells. Following this, a library of 1293 FDA-approved drugs was screened via molecular docking, MD simulation, and MMPBSA binding energy. Amongst the library of compounds, Adapalene exhibited the least binding energy of (-10.2 kCal/mol) in comparison to that of the chosen reference compound, Nilutamide (-8.6 kCal/mol). Furthermore, the in vitro efficacy of Adapalene was also determined in two different breast cancer cell lines such as MCF7 (AR-positive/ER-positive) and MDA-MB-231 (AR negative/TNBC). Initially, the cell viability assay (MTT) was performed, which endowed us with a lesser IC50 value of Adapalene in comparison to Nilutamide in both cell lines. The IC50 of Adapalene was found to be 12 µM and 39.4 µM in MCF7 and MDA-MB-231 cells, respectively. Furthermore, Adapalene also induced cellular ROS and apoptosis by 3.5-fold and 26.58% in MCF7 cells. However, the overall effect of Adapalene was significantly lower in the case of MDA-MB-231 cell lines, which could be attributed to its inherent nature of the absence of hormone receptors. Conclusively, Adapalene possesses greater therapeutic efficacy in comparison to the control drug, thereby hinting towards the potential use of Adapalene in the treatment of AR-positive breast cancer.

AbobotulinumtoxinA improves skin properties and sebum quality in the rhino mouse.

Besides neuronal cells, botulinum neurotoxins (BoNTs) can also affect other cell types such as fibroblasts or keratinocytes. These cells play a key role in skin conditions. Maintaining a high-quality sebum secretion is essential to avoid premature aging. This study explored the effect of abobotulinumtoxinA (aboBoNT-A) in the rhino mouse. Briefly, anaesthetized animals were injected via the intra-dermal route (ID; four sites of injection) by either vehicle or 0.1, 0.3 and 1 Unit aboBoNT-A per mouse. A reference group was administered with adapalene gel 0.1% (daily local application) for 15 days. Adapalene is a third-generation retinoid and is used as first-line treatment of moderate acne. The body weight and the thickness of the dorsal skin were measured on days 1, 5, 10 and 15; erythema and scaling were recorded at the same time. On day 15, animals were ethically euthanized and skin samples were collected for histology, ELISA and lipidomic assays. AboBoNT-A administered ID at the doses 0.1 U and 0.3 U per mouse was well tolerated. 1 U aboBoNT-A (per mouse) induced a transient loss of muscle tone associated with a slight body weight loss after which mice recovered a good health status. AboBoNT-A did not show any significant effect on utricles surface area but induced a significant anti-inflammatory effect on dermis at the two highest doses. Moreover, aboBoNT-A showed neither side effects commonly observed with local retinoids, nor hyperplasia or dermis inflammation. No change in skin Interleukin-1alpha (IL-1α) cytokine levels was evidenced with aboBoNT-A, whereas a dose-dependent increase of substance P (SP) concentration in the skin was recorded, suggesting that aboBoNT-A induces neuropeptide accumulation in tissue by inhibiting exocytosis mechanisms. Lipidomic analysis showed that aboBoNT-A significantly increased the sebum concentration of several lipid species, presenting skin protecting properties. Overall, these data suggest that ID aboBoNT-A has skin rejuvenation, anti-inflammatory and moisture-boosting properties.

Screening of Adapalene Microsponges Fabrication Parameters with Insight on the In vitro Biological Effectiveness.

Purpose: The objective of the present study was to scrutinize the microsponges (MS) as a carrier system using Adapalene (ADA) as a model drug. Methods: Data modelling was implemented using Plackett-Burman design to identify the main variables affecting the formulation of ADA-MS. The adopted method of preparation for MS was quasi-emulsion solvent diffusion method. The nominated independent variables were volume of organic phase, sonication time, stirring speed, drug percent, polymer type, emulsifier concentration, and method of organic phase addition. As for the dependent variables, they included entrapment efficiency (E.E.%), production yield (P.Y.%), particle size (P.S.) and morphology. Furthermore, selected ADA loaded microsponges (ADA-MS) were in vitro assayed for their biological activities via cytotoxicity, UVA irradiation and cell viability, and antimicrobial activity. Results: The study indicated that the drug percent, polymer type and surfactant concentration have the key significant effect on E.E.% and P.Y.%, while, the drug percent, stirring speed and volume of organic phase have had a significant effect on P.S. and their morphology. Furthermore, ADA-MS had a momentous cytotoxic effect on A431 and M10 cell-lines with exceptional enrichment when the polymer Eudragit RS100 was used. Also, the ADA-MS increased the cell viability after UVA irradiation on HFB-4 cell-line by 14% to 43%, especially when using Ethyl Cellulose as a polymer. Lastly, the antimicrobial activity of ADA against Propionibacterium acnes was boosted when incorporated into MS. Conclusion: The Plackett-Burman design proved its impact in discerning preparation variables affecting the quality of ADA-MS formulation, with heightening of the in vitro biological activities of ADA. Thus, MS was presumed to be an auspicious carrier system for ADA.

Adapalene induces adipose browning through the RARß-p38 MAPK-ATF2 pathway.

Adipose browning has recently been reported to be a novel therapeutic strategy for obesity. Because the retinoic acid receptor (RAR) is a potential target involved in browning, adapalene (AD), an anti-acne agent with RAR agonism, was examined in detail for its effects on adipose browning and the underlying mechanisms in vitro and in vivo. AD upregulated the expression of adipose browning-related markers in a concentration-dependent manner, promoted mitochondrial biogenesis, increased oxygen consumption rates, and lowered lipid droplet sizes in differentiated 3T3/L1 white adipocytes. Among the three retinoic acid receptors (RARα, RARß, and RARγ), knockdown of the gene encoding RARß mitigated AD-induced adipose browning. Similarly, LE135 (a selective RARß antagonist) attenuated AD action, suggesting that AD promotes adipose browning through RARß. Sequential phosphorylation of p38 mitogen-activated protein kinase (MAPK) and activating transcription factor 2 (ATF2) was critical for AD-induced adipose browning, based on the observations that either SB203580 (a p38 MAPK inhibitor) or ATF2 siRNA reduced the effects of AD. In vivo browning effects of AD were confirmed in C57BL/6J mice and high-fat diet-induced obese (DIO) mice after oral administration of AD either acutely or chronically. This study identifies new actions of AD as an adipose browning agent and demonstrates that RARß activation followed by increased phosphorylation of p38 MAPK and ATF2 appears to be a key mechanism of AD action.

Selective Activation of MST1/2 Kinases by Retinoid Agonist Adapalene Abrogates AURKA-Regulated Septic Arthritis.

Septic arthritis is a chronic inflammatory disorder caused by Staphylococcus aureus invasion of host synovium, which often progresses to impairment of joint functions. Although it is known that disease progression is intricately dependent on dysregulated inflammation of the knee joint, identification of molecular events mediating such imbalance during S. aureus-induced septic arthritis still requires detailed investigation. In this article, we report that Aurora kinase A (AURKA) responsive WNT signaling activates S. aureus infection-triggered septic arthritis, which results in inflammation of the synovium. In this context, treatment with adapalene, a synthetic retinoid derivative, in a mouse model for septic arthritis shows significant reduction of proinflammatory mediators with a simultaneous decrease in bacterial burden and prevents cartilage loss. Mechanistically, adapalene treatment inhibits WNT signaling with concomitant activation of HIPPO signaling, generating alternatively activated macrophages. Collectively, we establish adapalene as a promising strategy to suppress S. aureus-induced irreversible joint damage.

Ion Pair Strategy in Solid Lipid Nanoparticles: a Targeted Approach to Improve Epidermal Targeting with Controlled Adapalene Release, Resulting Reduced Skin Irritation.

PURPOSE: Adapalene (AD) is one of the main retinoids used in the topical therapy of acne, an extremely common skin disease usually associated with psychological morbidity. However, like other retinoids, AD is frequently associated with skin irritation. To overcome the skin irritation, we proposed the encapsulation of AD in solid lipid nanoparticles (SLNs) using the ion pair strategy. METHODS: The developed SLN-AD was characterized by high-performance liquid chromatography, differential scanning calorimetry, X-ray diffraction, synchrotron small-angle X-ray scattering, and transmission electron microscopy. In vitro permeation tests using porcine skin and in vivo mice skin irritation test were performed to evaluate, respectively, the drug's skin distribution and the skin irritation. RESULTS: The characterization studies were able to demonstrate that the proposed strategy effectively provided high AD encapsulation in SLNs and its incorporation into a hydrophilic gel. Sustained release, epidermal targeting, and less skin irritation were observed for SLN-AD gel in comparison to the marketed AD gel. CONCLUSIONS: The studies demonstrated that the encapsulation of AD in SLNs through the formation of an ion pair is a valuable alternative to diminish the adverse skin reactions caused by AD and can optimize patient adherence to treatment.

Application of ultrasound-mediated adapalene-coated lysozyme-shelled microbubbles in UVA-induced skin photoaging.

Photoaging, the premature aging of skin induced by ultraviolet rays, is characterized by wrinkling, roughness, laxity, and pigmentary changes. Various natural and synthetic retinoids have been explored for the treatment of aging. Among retinoids, adapalene (Ada, 0.3%) is one of the most potent and widely used drugs to treat photoaging. However, it causes irritant reactions that limit its acceptance by patients. Several studies have shown the applicability of Lysozyme (Lys)-shelled microbubbles (MBs) for drug delivery through sonophoresis, and recently we have shown its efficiency to treat inflammatory skin disease. Here, we report the construction of novel Ada-LysMBs based on opposite electric charges for combined effects to treat photoaging. The Ada-LysMBs were self-assembled and had a mean diameter of 2857 nm. The maximum loading efficiency of Ada onto LysMBs was 13.99 ± 0.59%. An acoustic power density of 3 W/cm2 for 1 min revealing maximum penetration depth of LysMBs was optimized for further in vitro and in vivo studies of Ada-LysMBs. It was observed that in vitro Ada release from Ada-LysMBs at 6 h after ultrasound (US) treatment was more rapid at pH 7.4 (82%) than at pH 5.5 (73%). Franz diffusion experiments on isolated porcine skin indicated that US approximately doubled Ada delivery by Ada-LysMBs and Ada + LysMBs at 12 h and six-fold Lys permeation by LysMBs at 6 h, compared to these treatments alone. A 5-week in vivo study in mice identified significant wrinkle reduction in animals treated with US plus Ada-LysMBs. Our findings indicate that US may be used with Ada-LysMBs in the water phase to treat photoaging by normalizing hyperkeratinization and promoting collagen synthesis.

Selective RAR agonists for acne vulgaris: A narrative review.

BACKGROUND: Acne vulgaris is a chronic disfiguring inflammatory disease of adolescents and adults affecting up to 90% of the population around the world. The sequence of etiopathogenesis in acne is not completely understood but involves abnormalities in sebum production, follicular plugging, proliferation of propionibacterium acnes, and chronic inflammation. AIMS: This review aims to summarize the features of the topical selective RAR agonists in treating acne vulgaris with a special emphasis on the 4th generation topical retinoid trifarotene. METHODS: Studies were identified by searching electronic databases (MEDLINE and PubMed) till August 2019 and reference lists of respective articles. Only articles published in English language were included. RESULTS: Topical retinoids have been first line of treatment for more than 30 years now in treating mild to moderate acne vulgaris. Third generation retinoids like adapalene and tazarotene are selective RAR and γ agonists, having an additional anti-inflammatory action along with their comedolytic effects and work well in combinations with topical antibiotics, due to the stability of chemical composition. CONCLUSION: Trifarotene is a new 4th generation retinoid with selective action on RAR-γ receptor alone, which is specific for skin, and it is safe for long-term maintenance therapy with good efficacy and tolerability.

The third-generation retinoid adapalene triggered DNA damage to induce S-phase arrest in HaCat cells.

Epidermal proliferative diseases consisted of a series of common skin diseases, most of which were recurrent chronic skin diseases, and had greatly negative influence on the life quality of patient. Retinoids exhibited vital roles in the treatment of many skin diseases. Our recent study demonstrated that adapalene significantly inhibited the growth of HaCat cells, and the inhibitory activity was stronger than other retinoids, such as all-trans-retinoic acid, acitretin, isotretinoin, tazarotene, and bexarotene. Further study showed that adapalene suppressed the colony formation of HaCat cells, and it dramatically triggered S-phase arrest and apoptosis, rather than G1 phase arrest which was reported in other retinoids in several studies. Additionally, adapalene treatment greatly upregulated the protein expression of DNA damage marker γ-H2AX, which was in accord with the results of the elongation of tail moment by comet electrophoresis analysis. Moreover, DNA damage was triggered and DNA repair was suppressed synchronously with adapalene treatment, which accounted for the mechanism of S-phase arrest induced by adapalene. In summary, our recent work demonstrated that adapalene showed strong anti-proliferation activity in HaCat cells and could be an alternative agent for the epidermal proliferative disease.

Adapalene inhibits ovarian cancer ES-2 cells growth by targeting glutamic-oxaloacetic transaminase 1.

Glutamic-oxaloacetic transaminase 1 (GOT1) regulates cellular metabolism through coordinating the utilization of carbohydrates and amino acids to meet nutrient requirements for sustained proliferation. As such, the GOT1 inhibitor may provide a new strategy for the treatment of various cancers. Adapalene has been approved by FDA for the treatment of acne, pimples and pustules, and it may also contribute to the adjunctive therapy for advanced stages of liver and colorectal cancers. In this work, we first examined the enzyme inhibition of over 500 compounds against GOT1 in vitro. As a result, Adapalene effectively inhibited GOT1 enzyme in a non-competitive manner. MST and DARTS assay further confirmed the high affinity between Adapalene and GOT1. Furthermore, the growth and migration of ovarian cancer ES-2 cells were obviously inhibited by the treatment of Adapalene. And it induced the apoptosis of ES-2 cells according to Western blot and Hoechst 33258 straining. In addition, molecular docking demonstrated that Adapalene coordinated in an allosteric site of GOT1 with low binding energy. Furthermore, knockdown of GOT1 in ES-2 cells decreased their anti-proliferative sensitivity to Adapalene. Together, our data strongly suggest Adapalene, as a GOT1 inhibitor, could be regarded as a potential drug candidate for ovarian cancer therapy.

Adapalene suppressed the proliferation of melanoma cells by S-phase arrest and subsequent apoptosis via induction of DNA damage.

Malignant melanoma was the leading cause of mortality among the skin-associated cancer owing to its highly metastatic feature, increasing incidence and drug resistance requirement. Retinoids played important roles in the treatment of cancer via the activation of retinoid acid receptor (RAR) or retinoid X receptor (RXR). Our present study showed that the third-generation retinoid adapalene exhibited strong inhibitory effects on the proliferation of melanoma cells than other retinoids, such as all-trans-retinoic acid (ATRA), isotretinoin, acitretin and bexarotene, and adapalene exerted significant inhibitory effects on the colony formation of melanoma cells. Further study confirmed that adapalene treatment triggered dramatic S phase arrest and apoptosis, and S phase arrest was the potential mechanism of apoptosis induction. In addition, adapalene treatment dramatically regulated the expression of S phase-related protein, and increased the protein level of DNA damage marker，which were consistent with the results of the induction of the tail moment in comet assays. Meanwhile, DNA damage response was activated and the DNA repair pathway was simultaneously inhibited by adapalene treatment, which might furtherly potentiate S phase arrest and subsequent apoptosis. Taken together, these results showed that adapalene exhibited strong anti-cancer activity, and might be a candidate agent for the clinical treatment of melanoma.

Identification of Retinoic Acid Receptor Agonists as Potent Hepatitis B Virus Inhibitors via a Drug Repurposing Screen.

Currently available therapies for chronic hepatitis B virus (HBV) infection can efficiently reduce viremia but induce hepatitis B surface antigen (HBsAg) loss in very few patients; also, these therapies do not greatly affect the viral covalently closed circular DNA (cccDNA). To discover new agents with complementary anti-HBV effects, we performed a drug repurposing screen of 1,018 Food and Drug Administration (FDA)-approved compounds using HBV-infected primary human hepatocytes (PHH). Several compounds belonging to the family of retinoic acid receptor (RAR) agonists were identified that reduced HBsAg levels in a dose-dependent manner without significant cytotoxicity. Among them, tazarotene exhibited the most potent anti-HBV effect, with a half-maximal inhibitory concentration (IC50) for HBsAg of less than 30 nM in PHH. The inhibitory effect was also observed in HBV-infected differentiated HepaRG (dHepaRG) models, but not in HepG2.215 cells, and HBV genotypes A to D were similarly inhibited. Tazarotene was further demonstrated to repress HBV cccDNA transcription, as determined by the levels of HBV cccDNA and RNAs and the activation of HBV promoters. Moreover, RNA sequence analysis showed that tazarotene did not induce an interferon response but altered the expression of a number of genes associated with RAR and metabolic pathways. Inhibition of RARß, but not RARα, by a specific antagonist significantly attenuated the anti-HBV activity of tazarotene, suggesting that tazarotene inhibits HBV in part through RARß. Finally, a synergistic effect of tazarotene and entecavir on HBV DNA levels was observed. Therefore, RAR agonists as represented by tazarotene were identified as potential novel anti-HBV agents.

Alkyl polyglucoside vs. ethoxylated surfactant-based microemulsions as vehicles for two poorly water-soluble drugs: physicochemical characterization and in vivo skin performance.

Two types of biocompatible surfactants were evaluated for their capability to formulate skin-friendly/non-irritant microemulsions as vehicles for two poorly water-soluble model drugs differing in properties and concentrations: alkyl polyglucosides (decyl glucoside and caprylyl/capryl glucoside) and ethoxylated surfactants (glycereth-7-caprylate/ caprate and polysorbate 80). Phase behavior, structural inversion and microemulsion solubilization potential for sertaconazole nitrate and adapalene were found to be highly dependent on the surfactants structure and HLB value. Performed characterization (polarized light microscopy, pH, electrical conductivity, rheological, FTIR and DSC measurements) indicated a formulation containing glycereth- 7-caprylate/caprate as suitable for incorporation of both drugs, whereas alkyl polyglucoside-based systems did not exhibit satisfying solubilization capacity for sertaconazole nitrate. Further, monitored parameters were strongly affected by sertaconazole nitrate incorporation, while they remained almost unchanged in adapalene-loaded vehicles. In addition, results of the in vivo skin performance study supported acceptable tolerability for all investigated formulations, suggesting selected microemulsions as promising carriers worth exploring further for effective skin delivery of model drugs.

Effect of retinoic acid on aquaporin 3 expression in keratinocytes.

To explore the possible mechanism of the third-generation retinoic acid drugs (isotretinoin, acitretin, adapalene) in inducing skin and mucosa dryness and rhagades; specifically, mechanism by which these drugs influence keratinocyte cell culture models in vitro (HaCaT) and aquaporin channel (AQP3) protein expression was investigated. Isotretinoin, acitretin, and adapalene were applied to human keratinocyte HaCaT cells. Immunohistochemistry, reverse transcriptase polymerase chain reaction, and western blotting were used to detect their effects on AQP3 expression in HaCaT cells at different concentrations (0.000, 0.001, 0.010, 0.060, and 0.100 mg/mL) or different at times (0, 6, 12, 24, and 48 h). At 0.010 mg/mL, maximal AQP3 expression was observed in HaCaT cells; this was significantly higher than the expressions at the other concentrations (P < 0.05). After treatment with isotretinoin, acitretin, or adapalene at 0.010 mg/mL for 12 h, the expression of AQP3 was the highest in the isotretinoin group, followed by the acitretin group, with the lowest expression in the adapalene group. However, the differences were not statistically significant (P > 0.05). Retinoic acid can increase AQP3 expression in HaCaT cells, with significant effects observed with 0.010 mg/mL isotretinoin treatment for 12 h. The side effects, namely skin and mucosa dryness caused by retinoic acid might be related to its effects on AQP3 expression.

Adapalene inhibits the activity of cyclin-dependent kinase 2 in colorectal carcinoma.

Cyclin-dependent kinase 2 (CDK2) has been reported to be overexpressed in human colorectal cancer; it is responsible for the G1­to­S­phase transition in the cell cycle and its deregulation is a hallmark of cancer. The present study was the first to use idock, a free and open­source protein­ligand docking software developed by our group, to identify potential CDK2 inhibitors from 4,311 US Food and Drug Administration­approved small molecular drugs with a re­purposing strategy. Among the top compounds identified by idock score, nine were selected for further study. Among them, adapalene (ADA; CD271,6­[3­(1­adamantyl)­4­methoxyphenyl]­2­naphtoic acid) exhibited the highest anti­proliferative effects in LOVO and DLD1 human colon cancer cell lines. Consistent with the expected properties of CDK2 inhibitors, the present study demonstrated that ADA significantly increased the G1­phase population and decreased the expression of CDK2, cyclin E and retinoblastoma protein (Rb), as well as the phosphorylation of CDK2 (on Thr­160) and Rb (on Ser­795). Furthermore, the anti­cancer effects of ADA were examined in vivo on xenograft tumors derived from DLD1 human colorectal cancer cells subcutaneously inoculated in BALB/C nude mice. ADA (20 mg/kg orally) exhibited marked anti­tumor activity, comparable to that of oxaliplatin (40 mg/kg), and dose­dependently inhibited tumor growth (P<0.05), while combined administration of ADA and oxaliplatin produced the highest therapeutic effect. To the best of our knowledge, the present study was the first to indicate that ADA inhibits CDK2 and is a potential candidate drug for the treatment of human colorectal cancer.