Autophagy Modulators in Cancer Therapy

Autophagy is a process of self-degradation that plays an important role in removing damaged proteins, organelles or cellular fragments from the cell. Under stressful conditions such as hypoxia, nutrient deficiency or chemotherapy, this process can also become the strategy for cell survival. Autophagy can be nonselective or selective in removing specific organelles, ribosomes, and protein aggregates, although the complete mechanisms that regulate aspects of selective autophagy are not fully understood. This review summarizes the most recent research into understanding the different types and mechanisms of autophagy. The relationship between apoptosis and autophagy on the level of molecular regulation of the expression of selected proteins such as p53, Bcl-2/Beclin 1, p62, Atg proteins, and caspases was discussed. Intensive studies have revealed a whole range of novel compounds with an anticancer activity that inhibit or activate regulatory pathways involved in autophagy. We focused on the presentation of compounds strongly affecting the autophagy process, with particular emphasis on those that are undergoing clinical and preclinical cancer research. Moreover, the target points, adverse effects and therapeutic schemes of autophagy inhibitors and activators are presented.

Miconazole induces protective autophagy in bladder cancer cells

Autophagy plays a dual function in cancer progression; autophagy activation can support cancer cell survival or contribute to cell death. Miconazole, a Food and Drug Administration-approved antifungal drug, has been implicated in oncology research recently. Miconazole was found to exert antitumor effects in various tumors, including bladder cancer (BC). However, whether it provokes protective autophagy has been never discussed. We provide evidence that miconazole induces protective autophagy in BC for the first time. The results indicated that 1A/1B-light chain 3 (LC3)-II processing and p62 expression were elevated after miconazole exposure. Also, adenosine monophosphate-activated protein kinase phosphorylation was increased after miconazole treatment. We also confirmed the autophagy-promoting effect of miconazole in the presence of bafilomycin A1 (Baf A1). The result indicates that a combination treatment of miconazole and Baf A1 improved LC3-II processing, confirming that miconazole promoted autophagic flux. The acridine orange, Lysotracker, and cathepsin D staining results indicate that miconazole increased lysosome formation, revealing its autophagy-promoting function. Finally, miconazole and autophagy inhibitor 3-methyladenine cotreatment further reduced the cell viability and induced apoptosis in BC cells, proving that miconazole provokes protective autophagy in BC cells. Our findings approve that miconazole has an antitumor effect in promoting cell apoptosis; however, its function of protective autophagy is needed to be concerned in cancer treatment.

Miconazole, a pharmacological barrier to skin fungal infections

INTRODUCTION

Miconazole (MCZ) is a time-honored antifungal of the imidazole class. MCZ exerts a multipronged effect on fungi. It inhibits the cytochrome P450 complex, including the 14α-demethylase enzyme required for ergosterol biosynthesis, in fungal cell membranes. In addition, intracellular accumulation of toxic methylated sterols occurs and the synthesis of triglycerides and phospholipids is altered. Disturbances in oxidative and peroxidative enzyme activities lead to an intracellular toxic concentration of hydrogen peroxide. As a result, intracellular organelle destruction then leads to cell necrosis. Farnesol synthesis stimulated in Candida spp. prevents the yeast-to-mycelium formation. MCZ is further active against Gram-positive bacteria.

AREAS COVERED

This review aims at revisiting the MCZ antifungal activity in dermatomycoses.

EXPERT OPINION

MCZ's wide spectrum of activity appears noteworthy. The full pharmacological profile of MCZ indicates its fungistatic profile through its effect on ergosterol biosynthesis. In addition, it exhibits a fungicidal effect against a number of fungal species, due to hydrogen peroxide accumulation. MCZ is characterized by high safety, efficacy and versatility, and a unique, multifaceted nature of activity in the treatment of dermatomycoses.

Prevalence of tinea pedis in professional and college soccer players versus non-athletes

OBJECTIVE

To assess and compare the prevalence of tinea pedis among professional soccer players, college soccer players, and non-athletes. We sought to assess the prevalence of various risk factors and their association with tinea pedis among these different groups.

DESIGN

Survey study.

SETTING

United States.

PATIENTS

Members of a United Soccer League (USL) professional team (N = 16), male (N = 16) and female (N = 14) NCAA soccer teams at a local college, and male (N = 15) and female (N = 15) non-athletes from a local medical school.

INTERVENTION

All participants anonymously answered questions on their risk factors for tinea pedis and underwent physical and mycological examinations.

MAIN OUTCOME MEASURES

Clinical exam, potassium hydroxide solution (KOH), and culture.

RESULTS

Tinea pedis infected 69% professional soccer players (11 of 16) compared with 69% of male college soccer players (11 of 16) and 43% of female college soccer players (6 of 14), whereas non-athletes demonstrated significantly less tinea pedis (P < 0.001), including 20% of male non-athletes (3 of 15) and 0% of female non-athletes (0 of 15).

CONCLUSIONS

These results indicate a need for improved primary prevention of tinea pedis among athletes. A preventive program involving education and coach participation is needed to target these individuals.

Treatments of tinea pedis

The severity of tinea pedis infection determines the course of treatment required. Mild infections may be resolved using a topical agent. More severe presentations (eg, dermatophytosis complex) may require treatment that eliminates the bacterial and fungal infection. Some topical monotherapies may exhibit both antifungal and antibacterial activity. In other instances, it may be necessary to combine an antifungal agent with an antibacterial agent. If inflammation is present, an agent with known anti-inflammatory action may need to be used. The chronic presentation of tinea pedis (dry type) sometimes does not respond well to topical therapy. In such instances, systemic antifungal therapy is required to ensure that adequate concentrations of the therapeutic agent are present at the site of infection.

Onychomycosis: strategies to improve efficacy and reduce recurrence

Fungal infections may be difficult to treat for several reasons. It is important to obtain the correct diagnosis, and select the appropriate antifungal agent and route. General considerations that may be associated with recurrent infections are, a genetic predisposition and suboptimal bioavailability of drug, resulting in insufficient concentration at the target site. The aetiologic organism, the severity of disease, other coexisting diseases, concomitant drug intake, and the presence of fungal infection at other sites are some factors that determine the choice of antifungal therapy and its route of administration, oral vs. topical lacquer. Local factors such as the thickness of the nail, presence of lateral onychomycosis, longitudinal spike, dermatophytoma and severe onycholysis are some factors that may determine the choice of secondary measures such as mechanical or topical treatment. Booster or supplemental therapy may be of benefit when the response to initial treatment is poorer than expected and unlikely to result in complete response. Steps should be taken to reduce the possibility of recurrence once cure has been achieved.

Fungicidal activities of commonly used disinfectants and antifungal pharmaceutical spray preparations against clinical strains of Aspergillus and Candida species

The antifungal efficacy of commercial chemical disinfectants and pharmaceutical antifungal agents against medically important moulds and yeast species was investigated. Chlorine, phenol, sodium dodecyl sulfate and quaternary ammonium salts were the chemical disinfectants, and bifonazole and terbinafine were the antifungal pharmaceutical products tested against clinical isolates of Aspergillus and Candida species. Fungal inocula were obtained from conidial preparations of two A. ochraceus strains and yeast cells of C. albicans, C. krusei and C. parapsilosis. The antifungal activities were evaluated either by determining the kill rate in a cell suspension media at different contact periods, or by examining the viability and growth on plates sprayed with the active ingredient. Chlorine (1%) was the only disinfectant with the ability to cause a rapid inactivation of all five strains. Phenol (5%) was equally effective against Candida species; however, a number of A. ochraceus conidia were able to survive this treatment for up to 1 h. Benzalkonium chloride (0.5%) and cetrimide (0.5%) were also able to disinfect the three Candida species rapidly; however, these two quaternary ammonium compounds were relatively ineffective against A. ochraceus. In spray experiments, quaternary ammonium compounds had a fungicidal activity against Candida species and were fungistatic against A. ochraceus conidia. All five fungal strains were able to resist 0.5% sodium dodecyl sulfate, present either in the suspension solution or on the sprayed plate. Of the two pharmaceutical antifungal products tested, bifonazole (1%) were essentially ineffective against all five strains. Terbinafine (1%) had a fungicidal activity against A. ochraceus and C. parapsilosis. In suspension experiments, an exposure to 0.01% terbinafine required a contact period of 1 h for a complete inactivation of A. ochraceus conidia and an onset of fungicidal effect on C. parapsilosis yeast cells. Terbinafine was only moderately effective against C. albicans and was completely ineffective against C. krusei.