RESUMO
In the present work, we report a new class of potent steroid sulphatase (STS) inhibitors based on 6-(1-phenyl-1H-1,2,3-triazol-4-yl)naphthalen-2-yl sulphamate derivatives. Within the set of new STS inhibitors, 6-(1-(1,2,3-trifluorophenyl)-1H-1,2,3-triazol-4-yl)naphthalen-2-yl sulphamate 3L demonstrated the highest activity in the enzymatic assay inhibiting the STS activity to 7.98% at 0.5 µM concentration. Furthermore, to verify whether the obtained STS inhibitors are able to pass through the cellular membrane effectively, cell line experiments have been carried out. We found that the lowest STS activities were measured in the presence of compound 3L (remaining STS activity of 5.22%, 27.48% and 99.0% at 100, 10 and 1 nM concentrations, respectively). The measured STS activities for Irosustat (used as a reference) were 5.72%, 12.93% and 16.83% in the same concentration range. Moreover, a determined IC50 value of 15.97 nM for 3L showed that this compound is a very promising candidate for further preclinical investigations.
Assuntos
Inibidores Enzimáticos/farmacologia , Esteril-Sulfatase/antagonistas & inibidores , Ácidos Sulfônicos/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Células MCF-7 , Estrutura Molecular , Esteril-Sulfatase/isolamento & purificação , Esteril-Sulfatase/metabolismo , Relação Estrutura-Atividade , Ácidos Sulfônicos/síntese química , Ácidos Sulfônicos/químicaRESUMO
Steroid sulphatase (STS), involved in the hydrolysis of steroid sulphates, plays an important role in the formation of both active oestrogens and androgens. Since these steroids significantly impact the proliferation of both oestrogen- and androgen-dependent cancers, many research groups over the past 30 years have designed and developed STS inhibitors. One of the main contributors to this field has been Prof. Barry Potter, previously at the University of Bath and now at the University of Oxford. Upon Prof. Potter's imminent retirement, this review takes a look back at the work on STS inhibitors and their contribution to our understanding of sulphate biology and as potential therapeutic agents in hormone-dependent disease. A number of potent STS inhibitors have now been developed, one of which, Irosustat (STX64, 667Coumate, BN83495), remains the only one to have completed phase I/II clinical trials against numerous indications (breast, prostate, endometrial). These studies have provided new insights into the origins of androgens and oestrogens in women and men. In addition to the therapeutic role of STS inhibition in breast and prostate cancer, there is now good evidence to suggest they may also provide benefits in patients with colorectal and ovarian cancer, and in treating endometriosis. To explore the potential of STS inhibitors further, a number of second- and third-generation inhibitors have been developed, together with single molecules that possess aromatase-STS inhibitory properties. The further development of potent STS inhibitors will allow their potential therapeutic value to be explored in a variety of hormone-dependent cancers and possibly other non-oncological conditions.
Assuntos
Inibidores Enzimáticos/farmacologia , Esteril-Sulfatase/antagonistas & inibidores , Animais , Vias Biossintéticas/efeitos dos fármacos , Ensaios Clínicos como Assunto , Desenvolvimento de Medicamentos , Inibidores Enzimáticos/química , Humanos , Esteril-Sulfatase/metabolismoRESUMO
Polyphenism is a form of developmental plasticity that transduces environmental cues into discontinuous, often disparate phenotypes. In some cases, polyphenism has been attributed to facilitating morphological diversification and even the evolution of novel traits. However, this process is predicated on the origins and evolutionary maintenance of genetic mechanisms that specify alternate developmental networks. When and how regulatory loci arise and change, specifically before and throughout the history of a polyphenism, is little understood. Here, we establish a phylogenetic and comparative molecular context for two dynamically evolving genes, eud-1 and seud-1, which regulate polyphenism in the nematode Pristionchus pacificus. This species is dimorphic in its adult feeding-structures, allowing individuals to become microbivores or facultative predators depending on the environment. Although polyphenism regulation is increasingly well understood in P. pacificus, the polyphenism is far older than this species and has diversified morphologically to enable an array of ecological functions across polyphenic lineages. To bring this taxonomic diversity into a comparative context, we reconstructed the histories of eud-1 and seud-1 relative to the origin and diversification of polyphenism, finding that homologues of both genes have undergone lineage-specific radiations across polyphenic taxa. Further, we detected signatures of episodic diversifying selection on eud-1, particularly in early diplogastrid lineages. Lastly, transgenic rescue experiments suggest that the gene's product has functionally diverged from its orthologue's in a non-polyphenic outgroup. In summary, we provide a comparative framework for the molecular components of a plasticity switch, enabling studies of how polyphenism, its regulation, and ultimately its targets evolve.
Assuntos
Evolução Biológica , Rabditídios , Animais , Especiação Genética , Fenótipo , FilogeniaRESUMO
The purpose of this review article is to provide an overview of recent achievements in the synthesis of novel steroid sulphatase (STS) inhibitors. STS is a crucial enzyme in the biosynthesis of active hormones (including oestrogens and androgens) and, therefore, represents an extremely attractive molecular target for the development of hormone-dependent cancer therapies. The inhibition of STS may effectively reduce the availability of active hormones for cancer cells, causing a positive therapeutic effect. Herein, we report examples of novel STS inhibitors based on steroidal and nonsteroidal cores that contain various functional groups (e.g. sulphamate and phosphorus moieties) and halogen atoms, which may potentially be used in therapies for hormone-dependent cancers. The presented work also includes examples of multitargeting agents with STS inhibitory activities. Furthermore, the fundamental discoveries in the development of the most promising drug candidates exhibiting STS inhibitory activities are highlighted.
Assuntos
Inibidores Enzimáticos/farmacologia , Esteril-Sulfatase/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Modelos Moleculares , Estrutura Molecular , Esteril-Sulfatase/química , Esteril-Sulfatase/metabolismoRESUMO
Little is known about the origin of the neuroactive steroids dehydroepiandrosterone sulphate (DHEAS) and pregnenolone sulphate (PregS) in the brain or of their subsequent metabolism. Using rat brain perfusion in situ, we have found 3 H-PregS to enter more rapidly than 3 H-DHEAS and both to undergo extensive (> 50%) desulphation within 0.5 min of uptake. Enzyme activity for the steroid sulphatase catalysing this deconjugation was enriched in the capillary fraction of the blood-brain barrier and its mRNA expressed in cultures of rat brain endothelial cells and astrocytes. Although permeability measurements suggested a net efflux, addition of the efflux inhibitors GF120918 and/or MK571 to the perfusate reduced rather than enhanced the uptake of 3 H-DHEAS and 3 H-PregS; a further reduction was seen upon the addition of unlabelled steroid sulphate, suggesting a saturable uptake transporter. Analysis of brain fractions after 0.5 min perfusion with the 3 H-steroid sulphates showed no further metabolism of PregS beyond the liberation of free steroid pregnenolone. By contrast, DHEAS underwent 17-hydroxylation to form androstenediol in both the steroid sulphate and the free steroid fractions, with some additional formation of androstenedione in the latter. Our results indicate a gain of free steroid from circulating steroid sulphates as hormone precursors at the blood-brain barrier, with implications for ageing, neurogenesis, neuronal survival, learning and memory.
Assuntos
Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Permeabilidade Capilar/fisiologia , Sulfato de Desidroepiandrosterona/metabolismo , Pregnenolona/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/irrigação sanguínea , Encéfalo/efeitos dos fármacos , Permeabilidade Capilar/efeitos dos fármacos , Masculino , Propionatos/farmacologia , Quinolinas/farmacologia , Ratos , Ratos WistarRESUMO
Dual aromatase-steroid sulfatase inhibitors (DASIs) lead to significant deprivation of estrogen levels as compared to a single target inhibition and thereby exhibited an additive or synergistic effect in the treatment of hormone-dependent breast cancer (HDBC). Triazole-bearing DASI's having structural features of clinically available aromatase inhibitors are identified as lead structures for optimization as DASI's. To identify the spatial fingerprints of target-specific triazole as DASI's, we have performed molecular docking assisted Gaussian field-based comparative 3D-QSAR studies on a dataset with dual aromatase-STS inhibitory activities. Separate contours were generated for both aromatase and steroid sulphates showing respective pharmacophoric structural requirements for optimal activity. These developed 3D-QSAR models also showed good statistical measures with the excellent predictive ability with PLS-generated validation constraints. Comparative steric, electrostatic, hydrophobic, HBA, and HBD features were elucidated using respective contour maps for selective target-specific favourable activity. Furthermore, the molecular docking was used for elucidating the mode of binding as DASI's along with the MD simulation of 100 ns revealed that all the protease-ligand docked complexes are overall stable as compared to reference ligand (inhibitor ASD or Irosustat) complex. Further, the MM-GBSA study revealed that compound 24 binds to aromatase as well as STS active site with relatively lower binding energy than reference complex, respectively. A comparative study of these developed multitargeted QSAR models along with molecular docking and dynamics study can be employed for the optimization of drug candidates as DASI's.Communicated by Ramaswamy H. Sarma.
Assuntos
Inibidores da Aromatase , Neoplasias da Mama , Humanos , Feminino , Inibidores da Aromatase/farmacologia , Inibidores da Aromatase/química , Esteril-Sulfatase/metabolismo , Neoplasias da Mama/tratamento farmacológico , Simulação de Acoplamento Molecular , Aromatase/química , Ligantes , Triazóis/farmacologia , Triazóis/química , Relação Quantitativa Estrutura-Atividade , Simulação de Dinâmica MolecularRESUMO
Hunter syndrome, or mucopolysaccharidosis (MPS) II, is a rare lysosomal disorder characterized by progressive, multi-system disease. As most symptoms cannot be reversed once established, early detection and treatment prior to the onset of clinical symptoms are critical. However, it is difficult to identify affected individuals early in disease, and therefore the long-term outcomes of initiating treatment during this optimal time period are incompletely described. We report long-term clinical outcomes of treatment when initiated prior to obvious clinical signs by comparing the courses of two siblings with neuronopathic Hunter syndrome (c.1504 T > G[p.W502G]), one who was diagnosed due to clinical disease (Sibling-O, age 3.7 years) and the other who was diagnosed before disease was evident (Sibling-Y, age 12 months), due to his older sibling's findings. The brothers began enzyme replacement therapy within a month of diagnosis. Around the age of 5 years, Sibling-O had a cognitive measurement score in the impaired range of <55 (average range 85-115), whereas Sibling-Y at this age received a score of 91. Sibling-O has never achieved toilet training and needs direct assistance with toileting, dressing, and washing, while Sibling-Y is fully toilet-trained and requires less assistance with daily activities. Both siblings have demonstrated sensory-seeking behaviors, hyperactivity, impulsivity, and sleep difficulties; however, Sibling-O demonstrates physical behaviors that his brother does not, namely biting, pushing, and frequent elopement. Since the time of diagnosis, Sibling-O has had significant joint contractures and a steady deterioration in mobility leading to the need for an adaptive stroller at age 11, while Sibling-Y at age 10.5 could hike more than 6 miles without assistance. After nearly a decade of therapy, there were more severe and life-limiting disease manifestations for Sibling-O; data from caregiver interview indicated substantial differences in Quality of Life for the child and the family, dependent on timing of ERT. The findings from this sibling pair provide evidence of superior somatic and neurocognitive outcomes associated with presymptomatic treatment of Hunter syndrome, aligned with current considerations for newborn screening.
RESUMO
Breast cancer is the most frequently diagnosed cancer in women and the second most common form of cancer, causing death after lung cancer, all across the globe at an alarming rate. The level of estrogens in breast cancer tissues of postmenopausal women is 10-40 folds higher than the non-carcinogenic breast tissues. As a result of this greater level of estrogen, breast tissue becomes more prone to develop breast cancer; mainly, estradiol plays a significant role in the initiation and development of hormone-dependent breast cancer. Androstenedione, Adrenal dehydroepiandrosterone sulfate, and estrone-sulfate also play an important role as precursors for estrogen biosynthesis. Estrogen deprivation exhibits an attractive phenomenon in the advancement of ideal therapeutics for the treatment of breast cancer. Inhibition of aromatase and sulphatase emerged as an attractive therapy for the treatment of hormone-dependent breast cancer via deprivation of estrogen by different pathways. The cocktail of aromatase and sulphatase inhibitors known as Dual Aromatase-sulphatase Inhibitors (DASIs) emerged as an attractive approach for effective estrogen deprivation. The present review article focused on the journey of dual aromatase-sulphatase inhibitors from the beginning to date (2020). Keeping in view the key observations, this review may be helpful for medicinal chemists to design and develop new and efficient dual aromatase-sulphatase inhibitors for the possible treatment of hormone- related breast cancer.
Assuntos
Inibidores da Aromatase , Neoplasias da Mama , Aromatase/metabolismo , Inibidores da Aromatase/farmacologia , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Estrogênios , Feminino , Humanos , Sulfatases/metabolismoRESUMO
Endometriosis is an incurable hormone-dependent inflammatory disease that causes chronic pelvic pain and infertility characterized by implantation and growth of endometrial tissue outside the uterine cavity. Symptoms have a major impact on the quality of life of patients resulting in socioeconomic, physical and psychological burdens. Although the immune system and environmental factors may play a role in the aetiology of endometriosis, oestrogen dependency is still considered a hallmark of the disorder. The impact of oestrogens such as oestrone and particularly, oestradiol, on the endometrium or endometriotic lesions may be mediated by steroids originating from ovarian steroidogenesis or local intra-tissue production (intracrinology) dependent upon the expression and activity of enzymes that regulate oestrogen biosynthesis and metabolism. Two key pathways have been implicated: while there is contradictory data on the participation of the aromatase enzyme (encoded by CYP19A1), there is increasing evidence that the steroid sulphatase pathway plays a role in both the aetiology and pathology of endometriosis. In this review, we consider the evidence related to the pathways leading to oestrogen accumulation in endometriotic lesions and how this might inform the development of new therapeutic strategies to treat endometriosis without causing the undesirable side effects of current regimes that suppress ovarian hormone production.
Assuntos
Endometriose/etiologia , Endometriose/metabolismo , Estrogênios/metabolismo , Sulfatos/metabolismo , Animais , Feminino , Humanos , Qualidade de Vida , Transdução de Sinais/fisiologia , Esteril-Sulfatase/genética , Esteril-Sulfatase/metabolismoRESUMO
In women, establishment of pregnancy is dependent upon 'fine-tuning' of the endometrial microenvironment, which is mediated by terminal differentiation (decidualisation) of endometrial stromal fibroblasts (ESFs). We have demonstrated that intracrine steroid metabolism plays a key role in regulating decidualisation and is essential for time-dependent expression of key factors required for endometrial receptivity. The primary aim of the current study was to determine whether sulphated steroids can act as precursors to bioactive sex steroids during decidualisation. We used primary human ESF and a robust in vitro model of decidualisation to assess the expression of genes associated with sulphation, desulphation and transport of sulphated steroids in human ESF as well as the impact of the steroid sulphatase (STS) inhibitor STX64 (Irosustat). We found evidence for an increase in both expression and activity of STS in response to a decidualisation stimulus with abrogation of oestrone biosynthesis and decreased secretion of the decidualisation marker IGFBP1 in the presence of STX64. These results provide novel insight into the contribution of STS to the intracrine regulation of decidualisation.
Assuntos
Endométrio/metabolismo , Transdução de Sinais/fisiologia , Esteril-Sulfatase/metabolismo , Sulfatos/metabolismo , Animais , Implantação do Embrião/fisiologia , Feminino , Humanos , GravidezRESUMO
Triclosan (TCS) is an antimicrobial compound found in personal care products, and consequently in greywater. After its release to the environment, it continues its antimicrobial action on indigenous microbial communities. Little is known about the environmental impacts of high levels of TCS, which may occur due to accumulation following long-term greywater application to soil. Soil microcosms were established using a silty clay loam and augmented with a range of TCS concentrations ranging from 500 to 7500 mg kg-1. Samples were analysed for substrate-induced respiration, microbial biomass and sulphatase activity. The soil augmented with the lowest concentration of TCS (500 mg kg-1) significantly decreased microbial biomass, with a calculated EC20 of 195 mg kg-1. Substrate-induced respiration indicated that the soil microbial community was impacted for all TCS concentrations; however, the community showed potential to recover over time. Sulphatase activity was less sensitive to TCS and was significantly impacted at high concentrations of TCS (>2500 mg kg-1). It is likely that TCS has selective toxicity for more susceptible microbes when introduced into the soil environment. At high levels, TCS could overwhelm TCS-degrading soil microbes.
Assuntos
Anti-Infecciosos Locais/farmacologia , Microbiota/efeitos dos fármacos , Microbiologia do Solo , Poluentes do Solo/farmacologia , Triclosan/farmacologia , Águas Residuárias/química , Microbiologia da Água , Poluentes da Água/farmacologia , Anti-Infecciosos Locais/análise , Microbiota/fisiologia , Poluentes do Solo/isolamento & purificação , Sulfatases/análise , Sulfatases/antagonistas & inibidores , Fatores de Tempo , Triclosan/análise , Águas Residuárias/análise , Poluentes da Água/isolamento & purificaçãoRESUMO
Most endometrial cancers (ECs) are diagnosed at an early stage and have a good prognosis. However, 20-30% develop recurrence and have poor survival. Recurrence-risk prediction at diagnosis is hampered by the scarcity of prognostic markers. Most ECs are estrogen related, and recent studies show that estrogen exposure in EC is controlled intracrinally. We aim at assessing any association between patient prognosis and the pathways controlling the intracrine estrogen generation in EC: (a) the balance between 17ß-hydroxysteroid-dehydrogenase-type 1 (HSD17B1), that generates active estrogens, and HSD17B2, converting active into poorly active compounds; (b) the balance between steroid sulphatase (STS, that activates estrogens) and estrogen-sulphotransferase (SULT1E1, that deactivates estrogens); (c) the levels of aromatase (ARO), that converts androgen into estrogens. mRNA levels of HSD17B1, HSD17B2, STS, SULT1E1 and ARO were determined among 175 ECs using cDNA microarray. Proteins were explored by immunohistochemistry. Patients with high mRNA of HSD17B1 had a poorer prognosis compared with those with low levels. Combining the expression of HSD17B1 and HSD17B2, patients with high tumour expression of HSD17B1 and low levels of HSD17B2 had the poorest prognosis. Contrarily, women that had high tumour levels of HSD17B2 and low of HSD17B1 had the best outcome. No differences were seen between mRNA level of other the genes analysed and prognosis. At the protein level, HSD17B2, STS and SULT1E1 were highly expressed, whereas HSD17B1 was low and ARO was almost absent. In conclusion, HSD17B1 is a promising marker to predict EC prognosis. Immunohistochemical detection of this protein in ECs has low sensitivity and should be improved for future clinical applications.
Assuntos
Neoplasias do Endométrio/metabolismo , Neoplasias do Endométrio/patologia , Estradiol Desidrogenases/metabolismo , RNA Mensageiro/metabolismo , Idoso , Aromatase/metabolismo , Biomarcadores Tumorais/metabolismo , Estrogênios/metabolismo , Feminino , Humanos , Recidiva Local de Neoplasia , Prognóstico , Esteril-Sulfatase/metabolismo , Sulfotransferases/metabolismoRESUMO
Prostate cancer is the primary cancer in males, with increasing global incidence rates making this malignancy a significant healthcare burden. Androgens not only promote normal prostate maturity but also influence the development and progression of prostate cancer. Intriguingly, evidence now suggests endogenous and exogenous oestrogens, in the form of phytoestrogens, may be equally as relevant as androgens in prostate cancer growth. The prostate gland has the molecular mechanisms, catalysed by steroid sulphatase (STS), to unconjugate and utilise circulating oestrogens. Furthermore, prostate tissue also expresses enzymes essential for local oestrogen metabolism, including aromatase (CYP19A1) and 3ß- and 17ß-hydroxysteroid dehydrogenases. Increased expression of these enzymes in malignant prostate tissue compared with normal prostate indicates that oestrogen synthesis is favoured in malignancy and thus may influence tumour progression. In contrast to previous reviews, here we comprehensively explore the epidemiological and scientific evidence on how oestrogens impact prostate cancer, particularly focusing on pre-receptor oestrogen metabolism and subsequent molecular action. We analyse how molecular mechanisms and metabolic pathways involved in androgen and oestrogen synthesis intertwine to alter prostate tissue. Furthermore, we speculate on whether oestrogen receptor status in the prostate affects progression of this malignancy.
Assuntos
Estrogênios/metabolismo , Neoplasias da Próstata/metabolismo , Tecido Adiposo/metabolismo , Androgênios/metabolismo , Animais , Humanos , Masculino , Próstata/metabolismo , Receptores de Estrogênio/metabolismoRESUMO
La Ictiosis ligada al cromosoma X (ILX), es una genodermatosis poco frecuente que afecta a varones, se manifiesta a partir del período neonatal y se caracteriza por: xerodermia, hiperqueratosis, descamación y en algunos casos, manifestaciones extracutáneas. La delección total o parcial de la enzima sulfatasa esteroidea, es la causa de las manifestaciones clínicas. Presentamos el caso clínico, de un paciente con manifestaciones clínicas y hallazgos en la anatomía patológica, compatibles con esta entidad tratado con tazarotene (gel).
X-linked ichthyosis (XLI) is a rare genodermatosis that affects men and manifests from the neonatal period and is characterized by xeroderma, hyperkeratosis, desquamation and in some cases, extracutaneous manifestations. The disease is of chronic evolution and undergoes partial improvement in the summer season. The total or partial deletion of the steroid sulphatase enzyme is the cause of the clinical manifestations. We present the case of a patient with clinical manifestations and findings in the pathological anatomy compatible with this entity, as well as ITS treatment with topical tazarotene 0.1% (gel) Weekly controls were performed and clinical benefit of lesion-free skin was observed up to 6 weeks after treatment discontinuation, followed by the progressive appearance of brownish scales that became thick and adherent with the passage of time.
RESUMO
La mucopolisacaridosis tipo II es una enfermedad lisosomal producida por la deficiencia de la enzima iduronato 2 sulfatasa. Es una condición infrecuente de herencia recesiva ligada al X, que puede producir importante discapacidad progresiva. El análisis molecular es una técnica útil en la confirmación diagnóstica, que además permite detección de portadores asintomáticos, brindando la oportunidad de asesoría genética. Se presenta el caso de un paciente con mucopolisacaridosis tipo II, en quien se documentó una nueva mutación patogénica en el Gen IDS.
Mucopolysaccharidosis type II is a lisosomal disorder caused by a deficiency of the iduronate 2 sulphatase enzyme. It is a rare metabolic disease with an X linked recessive inheritance that may cause important progressive disability. Molecular analysis is a useful technique to confirm diagnosis and to identify asymptomatic carriers, thus allowing genetic counseling. We report the case of a patient with Muchopolysacharidosis type II with a new pathogenic mutation in the IDS gene.
Assuntos
Humanos , Masculino , Pré-Escolar , MucopolissacaridosesRESUMO
Candida dubliniensis is an opportunistic yeast that has been recovered from several body sites in many populations; it is most often recovered from the oral cavities of human immunodeficiency virus-infected patients. Although extensive studies on epidemiology and phylogeny of C. dubliniensis have been performed, little is known about virulence factors such as exoenzymatic and hemolytic activities. In this study we compared proteinase, hyaluronidase, chondroitin sulphatase and hemolytic activities in 18 C. dubliniensis and 30 C. albicans strains isolated from AIDS patients. C. albicans isolates produced higher amounts of proteinase than C. dubliniensis (p < 0.05). All the tested C. dubliniensis strains expressed hyaluronidase and chondroitin sulphatase activities, but none of them were significantly different from those observed with C. albicans (p > 0.05). Hemolytic activity was affected by CaCl2; when this component was absent, we did not notice any significant difference between C. albicans and C. dubliniensis hemolytic activities. On the contrary, when we added 2.5 g percent CaCl2, the hemolytic activity was reduced on C. dubliniensis and stimulated on C. albicans tested strains (p < 0.05).
C. dubliniensis é uma levedura oportunista que, embora já tenha sido isolada de vários sítios anatômicos é, com maior frequência, encontrada na boca de pacientes infectados pelo HIV. Embora tenham sido realizados numerosos estudos sobre a epidemiologia e filogenia, seus fatores de virulência como atividade exoenzimática e atividade hemolítica, são, ainda, pouco conhecidos. Neste estudo comparou-se a atividade in vitro de proteinase, hialuronidase, condroitin sulfatase e atividade hemolítica de 18 cultivos de C. dubliniensis com 30 cultivos de C. albicans, todos isolados de pacientes com SIDA. Foi evidenciada maior atividade de proteinase em C. albicans em relação a C. dubliniensis (p < 0,05). Todos os isolados de C. dubliniensis evidenciaram atividade de hialuronidase e condroitin-sulfatase de forma similar ao observado com C. albicans (p > 0,05). Constatou-se que a atividade hemolítica foi influenciada pelo CaCl2; em sua ausência não foram observadas diferenças na atividade hemolítica das duas espécies; todavia, ao se agregar 2,5 por cento de CaCl2, a atividade hemolítica de C. dubliniensis foi reduzida enquanto a de C. albicans, estimulada (p < 0,05).