RESUMO
The mediator complex usually cooperates with transcription factors to be involved in RNA polymerase II-mediated gene transcription. As one component of this complex, MED27 has been reported in our previous studies to promote thyroid cancer and melanoma progression. However, the precise function of MED27 in breast cancer development remains poorly understood. Here, we found that MED27 was more highly expressed in breast cancer samples than in normal tissues, especially in triple-negative breast cancer, and its expression level was elevated with the increase in pathological stage. MED27 knockdown in triple-negative breast cancer cells inhibited cancer cell metastasis and stemness maintenance, which was accompanied by downregulation of the expression of EMT- and stem traits-associated proteins, and vice versa in non-triple-negative breast cancer. Furthermore, MED27 knockdown sensitized breast cancer cells to epirubicin treatment by inducing cellular apoptosis and reducing tumorsphere-forming ability. Based on RNA-seq, we identified KLF4 as the possible downstream target of MED27. KLF4 overexpression reversed the MED27 silencing-mediated arrest of cellular metastasis and stemness maintenance capacity in breast cancer in vitro and in vivo. Mechanistically, MED27 transcriptionally regulated KLF4 by binding to its promoter region at positions -156 to +177. Collectively, our study not only demonstrated the tumor-promoting role of MED27 in breast cancer progression by transcriptionally targeting KLF4, but also suggested the possibility of developing the MED27/KLF4 signaling axis as a potential therapeutic target in breast cancer.
Assuntos
Neoplasias Mamárias Animais , Neoplasias de Mama Triplo Negativas , Humanos , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Neoplasias Mamárias Animais/genética , Complexo Mediador/genética , Complexo Mediador/metabolismo , Transdução de Sinais , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
The mechanisms behind the selection and initial recruitment of primordial follicles (PmFs) from the non-growing PmF pool during each estrous cycle in females remain largely unknown. This study demonstrates that PmFs closest to the ovulatory follicle are preferentially activated in mouse ovaries under physiological conditions. PmFs located within 40 µm of the ovulatory follicles were more likely to be activated compared to those situated further away during the peri-ovulation period. Repeated superovulation treatments accelerated the depletion of the PmF reserve, whereas continuous suppression of ovulation delayed PmF reserve consumption. Spatial transcriptome sequencing of peri-ovulatory follicles revealed that ovulation primarily induces the degradation and remodeling of the extracellular matrix (ECM). This ECM degradation reduces mechanical stress around PmFs, thereby triggering their activation. Specifically, Cathepsin L (CTSL), a cysteine proteinase and lysosomal enzyme involved in ECM degradation, initiates the activation of PmFs adjacent to ovulatory follicles in a distance-dependent manner. These findings highlight the link between ovulation and selective PmF activation, and underscore the role of CTSL in this process under physiological conditions.
Assuntos
Catepsina L , Matriz Extracelular , Folículo Ovariano , Ovulação , Animais , Feminino , Camundongos , Folículo Ovariano/metabolismo , Catepsina L/metabolismo , Ovulação/fisiologia , Matriz Extracelular/metabolismo , Ovário/metabolismo , Ciclo Estral/fisiologiaRESUMO
OBJECTIVE: This study's objective is to assess the efficacy and safety of Pulsed Magnetic Therapy System (PMTS) in improving insomnia disorder. METHODS: Participants with insomnia disorder were randomly assigned to receive either PMTS or sham treatment for four weeks (n= 153; PMTS: 76, sham: 77). Primary outcomes are the Insomnia Severity Index (ISI) scores at week 0 (baseline), 1, 2, 3, 4 (treatment), and 5 (follow-up). Secondary outcomes are the Pittsburgh Sleep Quality Index at baseline and week 4, and weekly sleep diary-derived values for sleep latency, sleep efficiency, real sleep time, waking after sleep onset, and sleep duration. RESULTS: The ISI scores of the PMTS group and the sham group were 7.13±0.50, 11.07±0.51 at week 4, respectively. There was a significant group×time interaction for ISI (F3.214, 485.271=24.25, p<0.001, ηp 2=0.138). Only the PMTS group experienced continuous improvement throughout the study; in contrast, the sham group only experienced a modest improvement after the first week of therapy. At the end of the treatment and one week after it, the response of the PMTS group were 69.7% (95% confidence interval [CI]: 58.6%-79.0%), 75.0% (95% CI: 64.1%-83.4%), respectively, which were higher than the response of the sham group (p<0.001). For each of the secondary outcomes, similar group×time interactions were discovered. The effects of the treatment persisted for at least a week. CONCLUSION: PMTS is safe and effective in improving insomnia disorders.
RESUMO
OBJECTIVE: To screen the optimal acupuncture regimen for cricopharyngeal achalasia (CPA) after brain stem infarction and compare the therapeutic effect between the combined therapy of catheter balloon dilation and acupuncture and the simple application of catheter balloon dilation. METHODS: The patients suffering from neuropathic dysphagia in CPA after brain stem infarction were selected as the subjects. After confirmed in the diagnosis with video fluoroscopic swallowing study (VFSS), they were randomized into 6 groups, 15 cases in each one, named group A (routine treatment), group B (catheter balloon dilation), group C1 (treated with acupuncture in local area), group C2 (treated with acupuncture based on zangfu differentiation), group C3 (treated with acupuncture at the local area and the acupoints based on zangfu differentiation) and group D (catheter balloon dilation combined with the optimal acupuncture). Two phases were included in the study. In the first phase of study, the therapeutic effect was compared among the three acupuncture groups, named C1, C2 and C3 group, so as to screen the optimal acupuncture regimen. In the group C1, the main acupoints included Fengchi (GB 20), Wangu (GB 12), Yifeng (TE 17) and three-tongue points (Extra). In the group C2, the main acupoints were Neiguan (PC 6), Tongli (HT 5), Zusanli (ST 36) and Sanyinjiao (SP 6) as well as the supplementary acupoints in accordance with the syndrome differentiation. In the group C1 and group C2, after deqi, the electroacupuncture was used, with continuous dense wave, 5 to 8 Hz in frequency. The needles were retained for 30 min. Acupuncture was given once a day, 5 treatments a week. Before treatment, in 6 weeks of treatment or after removal of gastric tube, the rehabilitation was evaluated. In the group C3, the acupoints, manipulation and treating course were same as the group C1 and group C2. In the 2nd phase of study, theresults of rehabilitation treatment were compared among the group A, group B and group D. The treatment was given once a day, 5 times a week. Before treatment, after gastric tube removal or in 6 weeks of treatment, the evaluation was conducted. The feeding-swallowing function grade and VFSS were adopted in the evaluation among the above 6 groups. RESULTS: â In the VFSS comparison at 1st phase of study after treatment, the food transporting ability at oral dysphagia, the results in the group C3 and group C1 were better obviously than the group C2 (both P<0.05). For the improvement in aspiration, the result in the group C3 was better obviously than the group C2 (P<0.05). In comparison of the three acupuncture groups with the group A, the difference was not significant statisticallys in the extubation rate among the four groups (P>0.05). The severity of dysphagia in the group C3 was milder than the group C2 and group A (both P<0.05). â¡ In the VFSS comparison at the 2nd phase of study, for the food transporting ability, the results in the group D and the group B were obviously better than the group A (both P<0.05). Regarding the function at the pharyngeal dysphagia and aspiration, the results in the group D were better than the group B and group A, those in the group B were better than the group A (all P<0.05). The difference in the extubation rate among the group A, group B and group D after treatment was significant statistically (P<0.01), of which, the extubation rate in the group D was the highest and the rate in the group A was the lowest. The dysphagia degree in the group D was milder than the group B and group A and that in the group B was milder than the group A (all P<0.05). CONCLUSION: In the study of the different acupuncture methods, the acupuncture at the local acupoints and the acupoints selected based on zangfu differentiation is the optimal acupuncture regimen for cricopharyngeal achalasia after brain stem infarction. The catheter balloon dilation combined with acupuncture present the synergistc effect on cricopharyngeal achalasia after brain stem infarction, obviously relieve dysphagia and reduce aspiration.
Assuntos
Terapia por Acupuntura , Infartos do Tronco Encefálico , Acalasia Esofágica , Pontos de Acupuntura , Terapia por Acupuntura/métodos , Infartos do Tronco Encefálico/complicações , Cateterismo , Dilatação , Acalasia Esofágica/etiologia , Acalasia Esofágica/terapia , Humanos , Resultado do TratamentoRESUMO
Bromodomain PHD finger transcription factor (BPTF), a core subunit of nucleosome-remodeling factor (NURF) complex, plays an important role in chromatin remodeling. However, its precise function and molecular mechanism involved in hepatocellular carcinoma (HCC) growth are still poorly defined. Here, we demonstrated the tumor-promoting role of BPTF in HCC progression. BPTF was highly expressed in HCC cells and tumor tissues of HCC patients compared with normal liver cells and tissues. Knockdown of BPTF inhibited cell proliferation, colony formation and stem cell-like traits in HCC cells. In addition, BPTF knockdown effectively sensitized the anti-tumor effect of chemotherapeutic drugs and induced more apoptosis in HCC cells. Consistently, knockdown of BPTF in a xenograft mouse model also suppressed tumor growth and metastasis accompanied by the suppression of cancer stem cells (CSC)-related protein markers. Moreover, the mechanism study showed that the tumor-promoting role of BPTF in HCC was realized by transcriptionally regulating the expression of human telomerase reverse transcriptase (hTERT). Furthermore, we found that HCC patients with high BPTF expression displayed high hTERT expression, and high BPTF or hTERT expression level was positively correlated with advanced malignancy and poor prognosis in HCC patients. Collectively, our results demonstrate that BPTF promotes HCC growth by targeting hTERT and suggest that the BPTF-hTERT axis maybe a novel and potential therapeutic target in HCC.
Assuntos
Antígenos Nucleares/metabolismo , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Células-Tronco Neoplásicas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Transdução de Sinais , Telomerase/metabolismo , Fatores de Transcrição/metabolismo , Animais , Antígenos Nucleares/genética , Antineoplásicos/metabolismo , Biomarcadores , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células , Autorrenovação Celular/genética , Células Cultivadas , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/genética , Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Imuno-Histoquímica , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Metástase Neoplásica , Proteínas do Tecido Nervoso/genética , Prognóstico , Fatores de Transcrição/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
CPSF4 was identified as a crucial tumorigenic factor in lung cancer development. However, its precise function and the underlying molecular mechanisms in colon cancer progression remain completely unknown. Here, we demonstrate CPSF4 was highly expressed in human colon cancer cells and tissues. Its knockdown inhibited colorectal cancer progression in vitro, including cell proliferation, migration, invasion and stemness maintenance. In contrast, the ectopic overexpression of CPSF4 had the opposite effects in vitro and in vivo. Further mechanistic studies demonstrated that CPSF4 facilitated colorectal tumorigenesis and development partially through transcriptionally regulating hTERT expression by cooperating with NF-kB1 and co-anchoring at hTERT promoter -321 to -234 fragment. In addition, clinical samples analysis indicated that CPSF4 expression was positively correlated with hTERT, and the simultaneously high expression of CPSF4 and hTERT predicted poor patient outcome. Overall, our findings established CPSF4 as a pro-tumorigenic factor in colorectal cancer progression, and suggested that targeting CPSF4-hTERT axis may represent a promising therapeutic strategy in colon cancer treatment.
Assuntos
Fator de Especificidade de Clivagem e Poliadenilação/metabolismo , Neoplasias do Colo/metabolismo , Progressão da Doença , Predisposição Genética para Doença/genética , Fatores de Poliadenilação e Clivagem de mRNA/metabolismo , Animais , Ciclo Celular , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Sobrevivência Celular , Fator de Especificidade de Clivagem e Poliadenilação/genética , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fragmentos de Peptídeos/metabolismo , Regiões Promotoras Genéticas , Telomerase/metabolismo , Fatores de Poliadenilação e Clivagem de mRNA/genéticaRESUMO
BACKGROUND: As the selective inhibitor of BRAF kinase, vemurafenib exhibits effective antitumor activities in patients with V600 BRAF mutant melanomas. However, acquired drug resistance invariably develops after its initial treatment. METHODS: Immunohistochemical staining was performed to detect the expression of iNOS and hTERT, p-p65, Epcam, CD44, PCNA in mice with melanoma xenografts. The proliferation and migration of melanoma cells were detected by MTT, tumorsphere culture, cell cycle, cell apoptosis, AO/EB assay and colony formation, transwell assay and scratch assay in vitro, and tumor growth differences were observed in xenograft nude mice. Changes in the expression of key molecules in the iNOS/hTERT signaling pathways were detected by western blot. Nucleus-cytoplasm separation, and immunofluorescence analyses were conducted to explore the location of p50/p65 in melanoma cell lines. Flow cytometry assay were performed to determine the expression of CD44. Pull down assay and ChIP assay were performed to detect the binding ability of p65 at iNOS and hTERT promoters. Additionally, hTERT promoter-driven luciferase plasmids were transfected in to melanoma cells with indicated treatment to determine luciferase activity of hTERT. RESULTS: Melatonin significantly and synergistically enhanced vemurafenib-mediated inhibitions of proliferation, colony formation, migration and invasion and promoted vemurafenib-induced apoptosis, cell cycle arresting and stemness weakening in melanoma cells. Further mechanism study revealed that melatonin enhanced the antitumor effect of vemurafenib by abrogating nucleus translocation of NF-κB p50/p65 and their binding at iNOS and hTERT promoters, thereby suppressing the expression of iNOS and hTERT. The elevated anti-tumor capacity of vemurafenib upon co-treatment with melatonin was also evaluated and confirmed in mice with melanoma xenografts. CONCLUSIONS: Collectively, our results demonstrate melatonin synergizes the antitumor effect of vemurafenib in human melanoma by inhibiting cell proliferation and cancer-stem cell traits via targeting NF-κB/iNOS/hTERT signaling pathway, and suggest the potential of melatonin in antagonizing the toxicity of vemurafenib and augmenting its sensitivities in melanoma treatment.
Assuntos
Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antioxidantes/uso terapêutico , Melanoma/tratamento farmacológico , Melatonina/uso terapêutico , Células-Tronco Neoplásicas/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Neoplasias Cutâneas/tratamento farmacológico , Telomerase/antagonistas & inibidores , Vemurafenib/uso terapêutico , Animais , Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sinergismo Farmacológico , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Humanos , Masculino , Melatonina/farmacologia , Camundongos , Camundongos Nus , NF-kappa B/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Vemurafenib/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
OBJECTIVE: To retrospectively analyze the injury characteristics of victims and treatment strategies in the explosion accident on the 17th May 2018 in Xixia county (Xixia "May 17th" explosion accident). METHODS: Completion the Level Three treatment on time, which was depended on the leading role played by the regional trauma centers was the main rescuing mode of the work in Xixia county, where the primary and secondary treatments were the key parts. The three-level treatment model includes: the local hospital acts as a level-one emergency medical institution, county hospitals function as secondary emergency medical institutions, and other higher medical institutions are the tertiary first aid medical institutions. The pre-hospital and in-hospital emergency procedures were initiated immediately after the large-scale explosive burn being identified, the key to the successfully rescue was to set up a comprehensive treatment team for burns and trauma. Rescue team should involve burn department and other related departments, including the departments of emergency, general surgery, orthopedic, thoracic surgery, neurosurgery, plastic surgery, intensive care unit, blood transfusion unit, anesthesiology, and interventional radiology, etc. All the thirteen burned patients were male, with inhalation injury, blast injury, hemopneumothorax, brain injury, bone fractures, and etc. Eight of them (61.54%) had multiple organ dysfunction syndrome (MODS). MODS mainly involved respiratory, circulatory, liver, gastrointestinal tract, kidney and coagulation function. With the multi-discipline treatment, the wound of 6 severely-burned patients started healing and can be discharged after keeping the patency of airway, applying resuscitation fluid and comprehensive treatments such as debridement and dressing change. Among 7 patients with extensive deep burns, one case with skull-based fracture, open craniocerebral, extensive intracranial hemorrhage and hemopneumothorax, died 9 hours later. Another case died within 24 hours after injury due to obvious exudation on the site of early incision and relaxation of wound. The escharotomy, micro-dermis and allograft skin transplantation were carried out for five cases with extensive deep burns from the 4th day after the recovery of shock. One week later, the second stage of microsphere skin transplantation was performed. But all died of sepsis or fungal infection. RESULTS: (1) A total of 113 elderly patients with sepsis were enrolled in the final analysis, including 67 patients in sepsis group and 46 patients in septic shock group. Thirty-two patients were enrolled as healthy controls and 31 elderly patients with CAP as elderly pneumonia group. The PCT, CRP, Lac, APACHE II and SOFA scores of the patients in the three groups were higher than those of the healthy control group, and they were gradually increased with the severity of infection. There was no significant difference in gender or age among the groups. Compared with the healthy control group, the other three groups had higher LL-37 level after admission, the LL-37 levels in the sepsis group and the septic shock group were decreased with the prolongation of the hospitalization time, and they were lower than the pneumonia group at 7 days after admission [LL-37 (µg/L): 1 403.9±501.9, 1 517.1±676.4 vs. 1 608.4±816.2, both P > 0.05]. It was shown by correlation analysis that the LL-37 level in peripheral blood of elderly patients with sepsis was significantly negatively correlated with APACHE II score (r = -0.329, P = 0.007) and SOFA score (r = -0.344, P = 0.005), but no significant correlation with Lac was found (r = -0.128, P = 0.311). (2) The 28-day survival analysis revealed that of the 113 elderly patients with sepsis, 54 (47.8%) survived at 28 days and 59 (52.2%) died. There was no significant difference in gender, age, PCT or CRP levels at 1 day after admission between the two groups. The 1-day Lac, APACHE II and SOFA scores of the patients in the non-survival group were significantly higher than those in the survival group, they were gradually increased with the prolongation of the hospitalization time, and they were significantly higher than those in the survival group at 7 days after admission [Lac (mmol/L): 2.4 (1.4, 4.4) vs. 1.0 (0.8, 1.7), APACHE II score: 21.77±5.85 vs. 13.74±4.99, SOFA score: 9.62±4.78 vs. 3.18±2.71, all P < 0.01]. With the prolongation of admission, there was no significant change in LL-37 level of peripheral blood in the survival group. The LL-37 level in the non-survival group showed a downward tendency, and it was significantly lower than that in the survival group at 7 days after admission (µg/L: 1 277.8±642.6 vs. 1 620.6±461.6, P < 0.05). It was shown by ROC curve analysis that the LL-37 in peripheral blood, Lac, APACHE II score and SOFA score at 7-day of admission of elderly patients with sepsis had predictive value for prognosis, and LL-37 had the best predicted effect for 28-day death, the area under the ROC curve (AUC) of LL-37 was 0.670, 95% confidence interval (95%CI) = 0.513-0.757, when the optimal cut-off value was 1 283.0 µg/L, the sensitivity was 75.7%, and the specificity was 61.5%. CONCLUSIONS: MODS and infection often occur during the course especially for patients with extensive and deep burns due to the great explosion in Xixia county, most of whom were accompanied with MODS and infection. Therefore, assembling multi-discipline team for treating the group of explosively-burned patients can increase the survival rate and reduce the possibility of disability.
Assuntos
Traumatismos por Explosões/complicações , Traumatismos por Explosões/terapia , Explosões , APACHE , Acidentes , Idoso , Humanos , Masculino , Insuficiência de Múltiplos Órgãos/etiologia , Prognóstico , Curva ROC , Estudos Retrospectivos , Sepse/etiologiaRESUMO
Background: The aim of the present study was to test whether fine particulate matter (PM2.5) induces the expression of platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, and transforming growth factor-ß1 (TGF-ß1) in human bronchial epithelial cells (HBECs) in vitro via high-mobility group box 1 (HMGB1) receptor for advanced glycation end products (RAGE) signaling. Methods: Sprague-Dawley rats were exposed to motor vehicle exhaust (MVE) or clean air. HBECs were either transfected with a small interfering RNA (siRNA) targeting HMGB1 or incubated with anti-RAGE antibodies and subsequently stimulated with PM2.5. Results: The expression of HMGB1 and RAGE was elevated in MVE-treated rats compared with untreated rats, and PM2.5 increased the secretion of HMGB1 and upregulated RAGE expression and the translocation of nuclear factor κB (NF-κB) into the nucleus of HBECs. This activation was accompanied by an increase in the expression of PDGF-AB, PDGF-BB, and TGF-ß1. The HMGB1 siRNA prevented these effects. Anti-RAGE antibodies attenuated the activation of NF-κB and decreased the secretion of TGF-ß1, PDGF-AB, and PDGF-BB from HBECs. Conclusion: PM2.5 induces the expression of TGF-ß1, PDGF-AB, and PDGF-BB in vitro via HMGB1-RAGE signaling, suggesting that this pathway may contribute to the airway remodeling observed in patients with COPD.
Assuntos
Antígenos de Neoplasias/metabolismo , Proteína HMGB1/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Material Particulado/efeitos adversos , Fator de Crescimento Derivado de Plaquetas/metabolismo , Mucosa Respiratória/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Animais , Células Cultivadas , Feminino , Humanos , NF-kappa B/metabolismo , Ratos Sprague-DawleyRESUMO
A series of hydroxy- and methoxy-substituted paeonol thiosemicarbazone analogues were synthesized as potential tyrosinase inhibitors and their inhibitory effects on mushroom tyrosinase and inhibitory mechanism were evaluated. Paeonol thiosemicarbazone analogues have been found exhibiting more remarkable inhibition than their indexcompounds on mushroom tyrosinase. Among them, compound 2,4-dihydroxy acetophenone-4-phenyl-3-thiosemicarbazone (d1) had the most potent inhibition activity with the IC50 value of 0.006 ± 0.001 mM, displayed as a reversible competitive inhibitor. The inhibitory ability of o- or p-substituted acetophenone thiosemicarbazones was: di-substituted acetophenone thiosemicarbazones>mono-substituted acetophenone thiosemicarbazones>non-substituted acetophenone thiosemicarbazones. Copper ions chelation assay explained that compound d1 exhibited competitive inhibition by forming a chelate with the copper ions at the catalytic domain of tyrosinase as well as indicate a 1.5:1 binding ratio of compound d1 with copper ions. In the fluorescence spectrum study, compound d1 behaved stronger fluorescence quenching on tyrosinase towards d1-Cu(2+) complex, inhibiting tyrosinase mainly by means of chelating the two copper ions in the active site. The newly synthesized compounds may serve as structural templates for designing and developing novel tyrosinase inhibitors.