Is Candida albicans an opportunistic oncogenic pathogen?

Intratumor fungi specific mechanisms to influence cell death pathways and trigger tumor cell apoptosis

Cancer, uncontrolled cell growth due to the loss of cell cycle regulation, is often found to be associated with viral infections and, as recent studies show, with bacterial infections as well. Emerging reports also suggest a strong link between fungi and cancer. The crucial virulence trait of fungi, the switch from yeast (Y) to hyphal (H) form, is found to be associated with carcinogenesis. The physicochemical properties and signal transduction pathways involved in the switch to the hyphal form overlap with those of tumor cell formation. Inhibiting differentiation causes apoptosis in fungi, whereas preventing apoptosis leads to cancer in multicellular organisms. Literature on the fungi-cancer linkage, though limited, is increasing rapidly. This review examines cancer-specific fungal communities, the impact of fungal microbiome on cancer cell progression, similarities between fungal differentiation and cells turning cancerous at biochemical and molecular levels, including the overlaps in signal transduction pathways between fungi and cancer. Based on the available evidence, we suggest that molecules inhibiting the yeast-hyphal transition in fungi can be combined with those targeting tumor cell apoptosis for effective cancer treatment. The review points out fertile research areas where mycologists and cancer researchers can collaborate to unravel common molecular mechanisms. Moreover, antibodies targeting fungal-specific chitin and glucan can be used for the selective neutralization of tumor cells. These new combinations of potential therapies are expected to facilitate the development of target-specific, less harmful and commercially feasible anticancer therapies. We bring together available evidence to argue that fungal infections could either trigger cancer or have a significant role in the development and progression of cancer. Hence, cancer-associated fungal populations could be utilized as a target for a combination therapy involving the integration of anticancer and antifungal drugs as well as inhibitors of fungal morphogenesis to develop more effective anticancer therapies.

The Role of Oral Yeasts in the Development and Progression of Oral Squamous Cell Carcinoma: A Scoping Review

The role of oral yeasts in oral squamous cell carcinoma (OSCC) has gained attention due to evidence linking fungal dysbiosis to carcinogenesis. While Candida albicans has been the primary focus, emerging studies highlight the importance of non-Candida species yeast genera. This scoping review synthesises the evidence on the role of oral yeasts, including Candida spp. and non-Candida species, in the development and progression of OSCC. A PRISMA-ScR-guided search was conducted in Medline, Embase, EBM Reviews, and CINAHL. Observational and experimental studies involving humans with OSCC, oral potentially malignant disorders (OPMDs), or oral epithelial dysplasia (OED) were included. This review analysed 75 studies. Research on oral yeast in OSCC has progressed since the 1970s, with advancements in identification techniques-from conventional culture methods to metagenomic sequencing and multi-omics approaches-alongside improved animal and cellular models of OSCC. These methodological advancements have identified notable distinctions in the oral mycobiome between carcinomatous and healthy states. Clinical findings reinforce the hypothesis that oral yeasts, particularly Candida spp., actively contribute to the dysplasia-carcinoma sequence. Emerging evidence suggests that oral yeasts may significantly modulate events contributing to OSCC progression. However, further mechanistic studies and robust clinical evidence are essential to establish causality and clarify their role in OSCC.

E-Cigarette effects on oral health: A molecular perspective

Electronic cigarettes (e-cigarettes) have emerged as a potential alternative to traditional smoking and may aid in tobacco harm reduction and smoking cessation. E-cigarette use has notably increased, especially among young non-tobacco users, raising concerns due to the unknown long-term health effects. The oral cavity is the first and one of the most crucial anatomical sites for the deposition of e-cigarette aerosols. E-cigarette aerosols contain nicotine, flavors, volatile organic compounds, heavy metals, carcinogens, and other hazardous substances. These aerosols impact the oral cavity, disrupting host-microbial interactions and triggering gingivitis and systemic diseases. Furthermore, oral inflammation and periodontitis can be caused by proinflammatory cytokines induced by e-cigarette aerosols. The toxic components of e-cigarette aerosols increase the cellular reactive oxygen species (ROS) levels, reduce antioxidant capacity, increase DNA damage, and disrupt repair processes, which may further contribute to harmful effects on oral epithelum, leading to inflammatory and pre-malignant oral epithelial lesions. In this review, we analyze the toxicological properties of compounds in e-cigarette aerosols, exploring their cytotoxic, genotoxic, and inflammatory effects on oral health and delving into the underlying molecular mechanisms. Further research is essential to understand the impact of e-cigarettes on oral health and make informed regulatory decisions based on reliable scientific evidence.

Influence of Agaricus blazei Murill polysaccharides on synthesis, stabilization, acute toxicity and antifungal activity of copper (II) oxide nanoparticles

In general, nanomaterials tend to have better physical, chemical and biological properties than conventional materials. Furthermore, the polysaccharides from Agaricus blazei Murill mushroom have several pharmacological properties, in addition to low cytotoxicity and high biocompatibility. This work sought to merge the properties of CuO nanoparticles and Agaricus blazei Murill polysaccharides through syntheses and coatings with the aim of evaluating their toxicity in adult zebrafish and antifungal activity against C. albicans and C. parapsilosis. The nanoparticles were synthesized using the coprecipitation method and subsequently characterized in terms of their physicochemical properties using spectroscopic and thermoanalytical techniques. Furthermore, their composition was determined by X-Ray Diffraction and their morphology was studied using different microscopic techniques. CuO nanoparticles coated with Agaricus blazei Murill polysaccharides showed smaller particle size. Dispersions of nanoparticles coated with the polysaccharides were found to be more stable than their uncoated counterparts. The nanoparticles also showed antifungal activity against Candida sp. strains, with MIC50 values between 64 and 512 µg mL-1. It was observed that coating the materials with polysaccharides preserved their antifungal properties and reduced acute toxicity against adult zebrafish. Therefore, it is estimated that the CuO nanoparticles coated with Agaricus blazei Murill polysaccharides are innovative nanomaterials with potential for future clinical applications, especially in the topical treatment of candidiasis.

Mining for antifungal agents to inhibit biofilm formation of Candida albicans: A study on green synthesis, antibiofilm, cytotoxicity, and in silico ADME analysis of 2-amino-4H-pyran-3-carbonitrile derivatives

Candida albicans (C. albicans) biofilm infections are quite difficult to manage due to their resistance against conventional antifungal drugs. To address this issue, there is a desperate need for new therapeutic drugs. In the present study, a green and efficient protocol has been developed for the synthesis of 2-amino-4H-pyran-3-carbonitrile scaffolds 4a-i, 6a-j, and 8a-g by Knoevenagel-Michael-cyclocondensation reaction between aldehydes, malononitrile, and diverse enolizable C-H activated acidic compounds using guanidinium carbonate as a catalyst either under grinding conditions or by stirring at room temperature. This protocol is operationally simple, rapid, inexpensive, has easy workup and column-free purification. A further investigation of the synthesized compounds was conducted to examine their antifungal potential and their ability to inhibit the growth and development of biofilm-forming yeasts like fungus C. albicans. According to our findings, 4b, 4d, 4e, 6e, 6f, 6g, 6i, 8c, 8d, and 8g were found to be active and potential inhibitors for biofilm infection causing C. albicans. The inhibition of biofilm by active compounds were observed using field emission scanning electron microscopy (FESEM). Biofilm inhibiting compounds were also tested for in vitro toxicity by using 3T3-L1 cell line, and 4b, 6e, 6f, 6g, 6i, 8c, and 8d were found to be biocompatible. Furthermore, the in silico ADME descriptors revealed drug-like properties with no violation of Lipinski's rule of five. Hence, the result suggested that synthesized derivatives could serve as a useful aid in the development of novel antifungal compounds for the treatment of fungal infections and virulence in C. albicans.

Oral Microbial Changes in Oral Squamous Cell Carcinoma: Focus on Treponema denticola, Lactobacillus casei, and Candida albicans

Background and Objectives: In this study, we aimed to explore the oral bacteria and fungi that can help discern oral squamous cell carcinoma (OSCC) and investigate the correlations between multiple key pathogens. Materials and Methods: Twelve participants (8 females and 4 males; mean age, 54.33 ± 20.65 years) were prospectively recruited into three groups: Group 1: healthy control, Group 2: patients with stomatitis, and Group 3: patients with OSCC, with 4 individuals in each group. Unstimulated whole saliva samples from these participants were analyzed using real-time PCR to assess the presence and abundance of 14 major oral bacterial species and Candida albicans. Results: The analysis revealed significant differences for certain microorganisms, namely, Treponema denticola (T. denticola), Lactobacillus casei (L. casei), and Candida albicans. T. denticola was most abundant in the OSCC group (5,358,692.95 ± 3,540,767.33), compared to the stomatitis (123,355.54 ± 197,490.86) and healthy control (9999.21 ± 11,998.40) groups. L. casei was undetectable in the healthy control group but was significantly more abundant in the stomatitis group (1653.94 ± 2981.98) and even higher in the OSCC group (21,336.95 ± 9258.79) (p = 0.001). A similar trend was observed for C. albicans, with DNA copy numbers rising from the healthy control (464.29 ± 716.76) to the stomatitis (1861.30 ± 1206.15) to the OSCC group (9347.98 ± 5128.54) (p = 0.006). The amount of T. denticola was positively correlated with L. casei (r = 0.890, p < 0.001) and C. albicans (r = 0.724, p = 0.008). L. casei's DNA copy number was strongly correlated with C. albicans (r = 0.931, p < 0.001). These three oral microbes exhibited strong positive correlations with each other and had various direct or indirect relationships with other species. Conclusions: In the OSCC group, T. denticola, L. casei, and C. albicans exhibited strong positive correlations with one another, further emphasizing the need for a deeper understanding of the complex microbial interactions in the OSCC environment.

Formulation and Development of a Herbal Antifungal Gel Containing Origanum vulgare and Syzygium aromaticum Essential Oils Against Oral Candida albicans

Background Oral candidiasis is the most prevalent oral fungal infection, and existing antifungal agents have side effects such as drug intolerance, resistance, and toxicity. Herbal essential oils are emerging as an alternative therapeutic approach for treating fungal infections. Origanum vulgare (O. vulgare), commonly known as oregano, and Syzygium aromaticum (S. aromaticum), commonly known as clove, are known to have antifungal properties and are effective against fluconazole-resistant strains. A combination of essential oils has a synergistic effect and aids in achieving effective antifungal activity at sufficiently low concentrations, which could lead to reduced side effects and resistance. Aim of the study This study aimed to formulate and develop an herbal antifungal gel containing O. vulgare and S. aromaticum and evaluate its synergistic antifungal efficacy against oral Candida albicans (C. albicans). Methodology Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) determinations of O. vulgare and S. aromaticum essential oils were performed individually and in combination to assess the antifungal activity against C. albicans. Based on the obtained MIC and MFC of essential oils in combination, an herbal antifungal gel was formulated. Further, to determine the biocompatible nature of the gel, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed. Results We found that a combination of O. vulgare and S. aromaticum essential oils showed antifungal activity at a lesser concentration, with a MIC of 0.19 μl/ml and MFC of 0.39 μl/ml when compared to their individual concentrations. Based on our results, an antifungal herbal gel comprising a concentration of 0.6 μl/ml of both essential oils was developed to achieve synergistic antifungal activity against oral C. albicans. The MTT assay of the herbal gel did not show any cytotoxicity. Conclusion The novel herbal antifungal gel containing O. vulgare and S. aromaticum is biocompatible in nature and provides an alternative therapeutic approach for treating oral candidiasis.

Green synthesis of biogenic selenium nanoparticles functionalized with ginger dietary extract targeting virulence factor and biofilm formation in Candida albicans

To treat the systemic infections caused by Candida albicans (C. albicans), various drugs have been used, however, infections still persisted due to virulence factors and increasing antifungal resistance. As a solution to this problem, we synthesized selenium nanoparticles (SeNPs) by using Bacillus cereus bacteria. This is the first study to report a higher (70 %) reduction of selenite ions into SeNPs in under 6 h. The as-synthesized, biogenic SeNPs were used to deliver bioactive constituents of aqueous extract of ginger for inhibiting the growth and biofilm (virulence factors) in C. albicans. UV-visible spectroscopy revealed a characteristic absorption at 280 nm, and Raman spectroscopy showed a characteristic peak shift at 253 cm-1 for the biogenic SeNPs. The synthesized SeNPs are spherical with 240-250 nm in size as determined by electron microscopy. Fourier transform infrared spectroscopy confirmed the functionalization of antifungal constituents of ginger over the SeNPs (formation of Ginger@SeNPs nanoconjugates). In contrast to biogenic SeNPs, nanoconjugates were active against C. albicans for inhibiting growth and biofilm formation. In order to reveal antifungal mechanism of nanoconjugates', real-time polymerase chain reaction (RT-PCR) analysis was performed, according to RT-PCR analysis, the nanoconjugates target virulence genes involved in C. albicans hyphae and biofilm formation. Nanoconjugates inhibited 25 % growth of human embryonic kidney (HEK) 293 cell line, indicating moderate cytotoxicity of active nanoconjugates in an in-vitro cytotoxicity study. Therefore, biogenic SeNPs conjugated with ginger dietary extract may be a potential antifungal agent and drug carrier for inhibiting C. albicans growth and biofilm formation.

The repertoire of mutational signatures in tobacco- and non-tobacco-induced oral cancer

The use of tobacco products is one of the established contributors toward the development and spread of oral cancer. Additionally, recent research has indicated oral microbiome, infections with Human papilloma virus (HPV), Epstein-Barr virus (EBV), Candida as significant contributing factors to this disease along with lifestyle habits. Deregulation of cellular pathways envisaging metabolism, transcription, translation, and epigenetics caused by these risk factors either individually or in unison is manifold, resulting in the increased risk of oral cancer. Globally, this cancer continues to exist as one of the major causes of cancer-related mortalities; the numbers in the developing South Asian countries clearly indicate yearly escalation. This review encompasses the variety of genetic modifications, including adduct formation, mutation (duplication, deletion, and translocation), and epigenetic changes evident in oral squamous cell carcinoma (OSCC). In addition, it highlights the interference caused by tobacco products in Wnt signaling, PI3K/Akt/mTOR, JAK-STAT, and other important pathways. The information provided also ensures a comprehensive and critical revisit to non-tobacco-induced OSCC. Extensive literature survey and analysis has been conducted to generate the chromosome maps specifically highlighting OSCC-related mutations with the potential to act as spectacles for the early diagnosis and targeted treatment of this disease cancer.

Artemisinins inhibit oral candidiasis caused by Candida albicans through the repression on its hyphal development

Candida albicans is the most abundant fungal species in oral cavity. As a smart opportunistic pathogen, it increases the virulence by switching its forms from yeasts to hyphae and becomes the major pathogenic agent for oral candidiasis. However, the overuse of current clinical antifungals and lack of new types of drugs highlight the challenges in the antifungal treatments because of the drug resistance and side effects. Anti-virulence strategy is proved as a practical way to develop new types of anti-infective drugs. Here, seven artemisinins, including artemisinin, dihydroartemisinin, artemisinic acid, dihydroartemisinic acid, artesunate, artemether and arteether, were employed to target at the hyphal development, the most important virulence factor of C. albicans. Artemisinins failed to affect the growth, but significantly inhibited the hyphal development of C. albicans, including the clinical azole resistant isolates, and reduced their damage to oral epithelial cells, while arteether showed the strongest activities. The transcriptome suggested that arteether could affect the energy metabolism of C. albicans. Seven artemisinins were then proved to significantly inhibit the productions of ATP and cAMP, while reduced the hyphal inhibition on RAS1 overexpression strain indicating that artemisinins regulated the Ras1-cAMP-Efg1 pathway to inhibit the hyphal development. Importantly, arteether significantly inhibited the fungal burden and infections with no systemic toxicity in the murine oropharyngeal candidiasis models in vivo caused by both fluconazole sensitive and resistant strains. Our results for the first time indicated that artemisinins can be potential antifungal compounds against C. albicans infections by targeting at its hyphal development.

A Putative Role of Candida albicans in Promoting Cancer Development: A Current State of Evidence and Proposed Mechanisms

Candida albicans is a commensal fungal species that commonly colonizes the human body, but it is also a pervasive opportunistic pathogen in patients with malignant diseases. A growing body of evidence suggests that this fungus is not only coincidental in oncology patients, but may also play an active role in the development of cancer. More specifically, several studies have investigated the potential association between C. albicans and various types of cancer, including oral, esophageal, and colorectal cancer, with a possible role of this species in skin cancer as well. The proposed mechanisms include the production of carcinogenic metabolites, modulation of the immune response, changes in cell morphology, microbiome alterations, biofilm production, the activation of oncogenic signaling pathways, and the induction of chronic inflammation. These mechanisms may act together or independently to promote cancer development. Although more research is needed to fully grasp the potential role of C. albicans in carcinogenesis, the available evidence suggests that this species may be an active contributor and underscores the importance of considering the impact of the human microbiome on cancer pathogenesis. In this narrative review, we aimed to summarize the current state of evidence and offer some insights into proposed mechanisms.

Studying TIGIT activity against tumors through the generation of knockout mice

The use of antibodies to block inhibitory receptors, primarily anti-PD1 and CTLA4 (known as checkpoint therapy) revolutionized cancer treatment. However, despite these successes, the majority of cancer patients do not respond to the checkpoint treatment, emphasizing the need for development of additional therapies, which are based on other inhibitory receptors. Human TIGIT is an inhibitory receptor expressed by Natural Killer (NK) and T cells and is mainly known to interact with PVR, Nectin-2, Nectin-3, and Nectin-4. Whether mouse TIGIT interacts with all of these ligands is still unclear. Additionally, the in vivo function of TIGIT against tumors is not completely understood. Here, we demonstrate that mouse TIGIT interacts with and is inhibited by mPVR only. Using CRISPR-Cas9 technology, we generated TIGIT-deficient mice and demonstrated that NK cell cytotoxicity and degranulation against two tumor types were lower in WT mice when compared to the TIGIT KO mice. Moreover, in vivo tumor progression was slower in TIGIT KO than in WT mice. Taken together, our data established that mTIGIT has only one ligand, PVR, and that in the absence of TIGIT tumors are killed better both in vitro and in vivo.

Coexpression network analysis of human candida infection reveals key modules and hub genes responsible for host-pathogen interactions

Invasive fungal infections are a significant reason for morbidity and mortality among organ transplant recipients. Therefore, it is critical to investigate the host and candida niches to understand the epidemiology of fungal infections in transplantation. Candida albicans is an opportunistic fungal pathogen that causes fatal invasive mucosal infections, particularly in solid organ transplant patients. Therefore, identifying and characterizing these genes would play a vital role in understanding the complex regulation of host-pathogen interactions. Using 32 RNA-sequencing samples of human cells infected with C. albicans, we developed WGCNA coexpression networks and performed DESeq2 differential gene expression analysis to identify the genes that positively correlate with human candida infection. Using hierarchical clustering, we identified 5 distinct modules. We studied the inter- and intramodular gene network properties in the context of sample status traits and identified the highly enriched genes in the correlated modules. We identified 52 genes that were common in the most significant WGCNA turquoise module and differentially expressed genes in human endothelial cells (HUVEC) infection vs. control samples. As a validation step, we identified the differentially expressed genes from the independent Candida-infected human oral keratinocytes (OKF6) samples and validated 30 of the 52 common genes. We then performed the functional enrichment analysis using KEGG and GO. Finally, we performed protein-protein interaction (PPI) analysis using STRING and CytoHubba from 30 validated genes. We identified 8 hub genes (JUN, ATF3, VEGFA, SLC2A1, HK2, PTGS2, PFKFB3, and KLF6) that were enriched in response to hypoxia, angiogenesis, vasculogenesis, hypoxia-induced signaling, cancer, diabetes, and transplant-related disease pathways. The discovery of genes and functional pathways related to the immune system and gene coexpression and differential gene expression analyses may serve as novel diagnostic markers and potential therapeutic targets.