Huan Mei

Itraconazole exerts its anti-melanoma effect by suppressing Hedgehog, Wnt, and PI3K/mTOR signaling pathways

Malignant melanoma is the deadliest form of all skin cancers. Itraconazole, a commonly used systemic antifungal drug, has been tested for its anti-tumor effects on basal cell carcinoma, prostate cancer, and non-small cell lung cancer. Whether itraconazole has any specific anti-tumor effect on melanoma remains unknown. However, the goal of this study is to investigate the effect of itraconazole on melanoma and to reveal some details of its underlying mechanism. In the in vivo xenograft mouse model, we find that itraconazole can inhibit melanoma growth and extend the survival of melanoma xenograft mice, compared to non-itraconazole-treated mice. Also, itraconazole can significantly inhibit cell proliferation, as demonstrated by Ki-67 staining in itraconazole-treated tumor tissues. In in vitro, we show that itraconazole inhibits the proliferation and colony formation of both SK-MEL-28 and A375 human melanoma cells. Moreover, we demonstrate that itraconazole significantly down-regulates Gli-1, Gli-2, Wnt3A, β-catenin and cyclin D1, while it up-regulates Gli-3 and Axin-1, indicating potent inhibitory effects of itraconazole on Hedgehog (Hh) and Wnt signaling pathways. Furthermore, itraconazole significantly suppresses the PI3K/mTOR signaling pathway – indicated by the down-regulated phosphorylation of p70S6K, 4E-BP1 and AKT – but has no effect on the phosphorylation of MEK or ERK. Our data suggest that itraconazole inhibits melanoma growth through an interacting regulatory network that includes Hh, Wnt, and PI3K/mTOR signaling pathways. These results suggest that this agent has several potent anti-melanoma features and may be useful in the synergesis of other anti-cancer drugs via blockage of the Hh, Wnt and PI3K/mTOR signaling pathways.

The Rpd3/Hda1 family of histone deacetylases regulates azole resistance in Candida albicans

OBJECTIVES The histone deacetylase (HDAC) has recently been linked to the morphogenesis and virulence of yeast. However, the effects of HDAC on antifungal susceptibility are not well understood. We sought to characterize the action of histone deacetylation on azole resistance in Candida albicans and its possible mechanism of action. METHODS A total of 40 C. albicans strains were studied. Azole susceptibility with or without trichostatin A (TSA) was determined according to the CLSI microdilution method. The null mutants of HDA1 and RPD3 (genes targeted by TSA) were also investigated using drop-plate assays and a rapid acquisition of adaptation to the azole test. Transcriptional levels of HDAC genes and efflux genes were quantified using RT-PCR for both the basal and fluconazole-induced conditions. RESULTS The inhibition of HDACs by TSA (0.25 mg/L) markedly reduced the trailing growth and the growth of most C. albicans strains. Trailing growth for C. albicans strains was decreased from 2-fold to 256-fold at 48 h. The deletion of HDA1 or RPD3 increased the susceptibility to azoles compared with the WT strain. The expression of HDA1 and RPD3 was up-regulated to different levels, and returned to the level of the susceptible parental strain when stable resistance had formed during the course of acquired fluconazole resistance both in vitro and in vivo. Efflux genes were poorly expressed in mutant strains compared with those of the WT strain. CONCLUSIONS Our results indicate the important role of the Rpd3/Hda1 family in the development of azole resistance in C. albicans. Histone deacetylation may govern the expression of genes related to the early stages of adaptation to azole stress, such as efflux pump genes.

Antifungal effects of undecylenic acid on the biofilm formation of Candida albicans.

Undecylenic acid can effectively control skin fungal infection, but the mechanism of its fungal inhibition is unclear. Hyphal growth of Candida albicans (C. albicans) and biofilm formation have been well recognized as important virulence factors for the initiation of skin infection and late development of disseminated infection. In this study, we seek to investigate antifungal mechanisms of undecylenic acid by evaluating the virulence factors of C. albicans during biofilm formation. We found that undecylenic acid inhibits biofilm formation of C. albicans effectively with optimal concentration above 3 mM. In the presence of this compound, the morphological transition from yeast to filamentous phase is abolished ultimately when the concentration of undecylenic acid is above 4 mM. Meanwhile, the cell surface is crumpled, and cells display an atrophic appearance under scanning electron microscopy even with low concentration of drug treatment. On the other hand, the drug treatment decreases the transcriptions of hydrolytic enzymes such as secreted aspartic protease, lipase, and phospholipase. Hyphal formation related genes, like HWP1, are significantly reduced in transcriptional level in drug-treated biofilm condition as well. The down-regulated profile of these genes leads to a poorly organized biofilm in undecylenic acid treated environment.

Subcutaneous infection by Ochroconis mirabilis in an immunocompetent patient

Recently, the taxonomy of Ochroconis (Ascomycota, Pezizomycotina, Venturiales, Sympoventuriaceae) has been revised with the recognition of an additional genus, Verruconis. Ochroconis comprises mesophilic saprobes that occasionally infect vertebrates which mostly are cold-blooded, while Verruconis contains thermophilic species which is a neurotrope in humans and birds. On the basis of molecular data it is noted that only a single Ochroconis species regularly infects immunocompetent human hosts. Here we report a subcutaneous infection due to Ochroconis mirabilis in a 50-year-old immunocompetent female patient. In vitro antifungal susceptibility tests revealed that terbinafine was the most effective drug. The patient was successfully cured with oral administration of terbinafine 250 mg daily in combination with 3 times of topical ALA-photodynamic therapy for 9 months.

Paeoniflorin suppresses IL-6/Stat3 pathway via upregulation of Socs3 in dendritic cells in response to 1-chloro-2,4-dinitrobenze.

Mounting evidence has suggested that inflammation is associated with IL-6/Stat3 pathway in dendritic cells (DCs) and Th17 cells, which are critical for development of allergic contact dermatitis (ACD). Paeoniflorin (PF) has been clinically proved to be effective in the treatment of inflammatory skin diseases such as ACD. We have previously demonstrated the effect of PF on DCs stimulated with 1-chloro-2,4-dinitrobenze (DNCB) and naïve CD4(+)CD45RA(+) T cells for Th17 cell differentiation. However, whether PF down-regulates IL-6/Stat3 in DCs and Th17 cells remains to be explored. In this study, we show clearly that PF markedly decreases IL-6/Stat3 in DCs stimulated with DNCB at both gene and protein levels compared with control DCs in vitro. Meanwhile, PF up-regulates suppressor of cytokine signaling 3 (Socs3). Such decreased expression of IL-6/Stat3 is abolished in DCs that were transfected with Socs3 short interfering RNA (siRNA). When mice CD4(+)CD45 RA(+) T cells were co-cultured with PF-treated DCs stimulated with/without DNCB, the gene expression of the Th17 cell markers such as retinoic acid-related orphan nuclear hormone receptor γt (RORγt), IL-17A, and IL-23R decreased, in accordance with the less secretions of IL-17 and IL-23 in vitro and in vivo. Finally, the suppressed Th17 differentiation induced by PF can be abolished by additional recombinant mouse IL-6. Our results suggest that the anti-inflammatory mechanisms introduced by depletion of Socs3 expression or inactivation of the negative regulator such as Socs3 may represent a promising strategy for the prevention of ACD.

Onychomycosis due to Chaetomium globosum with yellowish black discoloration and periungual inflammation

Onychomycosis is usually caused by dermatophytes, although also other filamentous and yeast-like fungi are associated with nail invasion. Chaetomium is an environmental genus of ascomycetes exhibiting a certain degree of extremotolerance. We report the first case of onychomycosis in a 46-year-old woman in China caused by Chaetomium globosum. The patient showed yellowish black discoloration with periungual inflammation on the left first toenail. We confirmed the causative agent, C. globosum, by KOH mount, culture, micromorphology and DNA sequence analysis

Chromoblastomycosis due to Fonsecaea monophora misdiagnosed as sporotrichosis and cutaneous tuberculosis in a pulmonary tuberculosis patient

Chromoblastomycosis is caused by dematiaceous fungi. It develops after inoculation of the organism into the skin. We report a case of chromoblastomycosis in a pulmonary tuberculosis patient without known history of trauma. The lesions were initially diagnosed as sporotrichosis and skin tuberculosis. Histopathology of scales and skin biopsy specimen revealed sclerotic bodies, the hallmark of chromoblastomycosis. The causative organism was identified as Fonsecaea monophora by rDNA ITS sequencing. The lesions recovered markedly after two month treatment with oral terbinafine 250 mg daily according to drug sensitive test in vitro in combination with local thermotherapy

Coccidioidomycosis: Imported and possible domestic cases in China: A case report and review, 1958-2017

We report a case of imported pulmonary coccidioidomycosis caused by Coccidioides posadasii in a patient who was misdiagnosed as tuberculosis and mistreated with antituberculosis medications for 18 months. The symptoms were not relieved until antifungal treatment was started. An extensive review of the coccidioidomycosis cases occurring in China reveals 38 cases, 16 of which had no associated history of travel to any traditional endemic areas. We speculate that some factors may drive Coccidioides spp. transference to China, which then causes those domestic infections. Moreover, we indicate the first, to the best of our knowledge, possible endemic areas in China.

Successful Treatment by Surgery of a Primary Cutaneous Mucormycosis Caused by Mucor irregularis

We report a case of primary cutaneous mucormycosis caused by Mucor irregularis. A 66-year-old man was presented to our hospital with a history of gradually enlarging plaque on the right leg for about a year. The identification of pathogen based on the fungus morphology and DNA sequencing revealed M. irregularis as the responsible fungus for skin lesion. The lesion was removed incidentally by a surgery procedure, and no recrudescence was seen during a follow-up of 24-month observation.

Silencing SOCS1 in dendritic cells promote survival of mice with systemic Candida albicans infection via inducing Th1-cell differentiation

Enhancing the immunity conferred by dendritic cells (DCs) to fungal infection represents a promising strategy in the number of immunocompromised individuals. In a previous study, we demonstrated that suppressor of cytokine signaling 1 (SOCS1) silencing can promote the maturation of DCs and induce an immune response against Candida albicans (C. albicans) in vitro. Herein, the effectiveness of SOCS1 suppression administered by SOCS1-siRNA-treated DCs is further evaluated in systemic candidiasis mouse model. The SOCS1-silenced DCs increase mouse survival and significantly decrease fungal colonization in the kidneys. We confirm that the serum IFN-γ levels in SOCS1-siRNA-treated mice are higher than in all other infected groups at the early stages of infection, which correlates with a higher differentiation of IFN-γ+CD4+ T cells (Th1) in the spleen. Meanwhile, the differentiation of IL-4-producing CD4+ T (Th2) or IL-17-producing CD4+ T cells (Th17 cells) remain unaffected under the same treatment, suggesting that SOCS1-silenced DCs significantly affect the IFN-γ-producing CD4+ T cells (Th1). However, at the late stages of infection when the differentiation of Th1, Th2 and Th17 cells decreases in SOCS1-silenced-DCs-treated mice, all the serum cytokines (IFN-γ, IL-4 and IL-17) are also reduced. In summary, treatment of mice with SOCS1-silenced DCs can protect mice from systemic infection during the early stages and thereby increase overall survival. We conclude that the increase in Th1 response in early stages avoids the cascade inflammatory response in later stages that is known to place such a large fungal load on the kidneys and cause subsequent death.