Ex vivo gene therapy for lysosomal storage disorders: future perspectives.

INTRODUCTION: Lysosomal storage disorders (LSD) are a group of monogenic rare diseases caused by pathogenic variants in genes that encode proteins related to lysosomal function. These disorders are good candidates for gene therapy for different reasons: they are monogenic, most of lysosomal proteins are enzymes that can be secreted and cross-correct neighboring cells, and small quantities of these proteins are able to produce clinical benefits in many cases. Ex vivo gene therapy allows for autologous transplant of modified cells from different sources, including stem cells and hematopoietic precursors. AREAS COVERED: Here, we summarize the main gene therapy and genome editing strategies that are currently being used as ex vivo gene therapy approaches for lysosomal disorders, highlighting important characteristics, such as vectors used, strategies, types of cells that are modified and main results in different disorders. EXPERT OPINION: Clinical trials are already ongoing, and soon approved therapies for LSD based on ex vivo gene therapy approaches should reach the market.

Somatic hypermutation profiles in stereotyped IGHV4-34 receptors from South American chronic lymphocytic leukemia patients.

Chronic lymphocytic leukemia (CLL) is the most common mature B-cell neoplasm in the West. IGHV4-34 is one of the most frequently used genes in CLL patients, which usually display an indolent outcome. In this study, we explored the mutational profile of CLL patients expressing IGHV4-34 within different stereotypes and their association with prognostic factors and clinical outcome. A multi-institutional cohort of unselected 1444 CLL patients was analyzed by RT-PCR and bidirectional sequencing. Cytogenetics and molecular cytogenetics analyses were also performed. We identified 144 (10%) IGHV4-34 expressing cases, 119 mutated (M), 44 of them with stereotyped B-cell receptors. Subset #4 was the most frequent (56.8% of cases) followed by subsets #16 (13.6%), #29 (6.8%), and #201 (2.3%), with different distribution among countries. Analysis of somatic hypermutation profile showed significant differences among stereotyped subsets for G28>D/E, P45>S, E55>Q, and S64>I changes (p < 0.01) and high frequency of disruption of the glycosylation motif in the VH CDR2 region. All stereotyped IGHV4-34 cases showed normal karyotypes. Deletion 13q14 as a sole alteration was present in 42.8% of stereotyped cases with a different distribution among subsets. A shorter time to first treatment was found in non-stereotyped vs. stereotyped M-IGHV4-34 patients (p = 0.034). Our results add new information supporting the importance of recurrent amino acid changes at particular positions, contributing to refine the molecular characterization of South American CLL patients.

Is there a role for epithelial-mesenchymal transition in adrenocortical tumors?

PURPOSE: Epithelial-mesenchymal transition (EMT) is a biological dynamic process by which epithelial cells lose their epithelial phenotype and acquire mesenchymal invasive and migratory characteristics. This has been postulated as an essential step during cancer progression and metastasis. Although this is well described in other tumors, the role of EMT in adrenocortical tumors (ACT) has yet to be addressed. METHODS: The aim of this study was to evaluate the expression of EMT markers e-cadherin, vimentin, and fibronectin, along with EMT-transcription factors (EMT-TFs), TWIST1, SIP1, and SNAIL in 24 adrenocortical carcinoma (ACC), 19 adrenocortical adenomas (ACA), 27 childhood-onset adrenocortical tumors (CAT), and 12 normal adrenal glands. The association of EMT and EMT-TFs with clinical outcomes and pathology features were also evaluated. RESULTS: Cytoplasmic vimentin expression was increased among CAT samples when compared to ACC, ACA, and normal adrenal samples (p < 0.001). There was no difference in e-cadherin and fibronectin expression observed between groups. Nuclear and cytoplasmic expression of TWIST1 and SIP1 was stronger in CAT and ACC vs. ACA and normal tissue samples (all, p < 0.05). ACT, regardless of classification, exhibited increased SNAIL expression when compared to normal tissue (p < 0.05). A significant correlation was observed between vimentin and TWIST1 (r s = 0.44, p < 0.001); SIP1 (r s = 0.51, p < 0.001); and SNAIL (r s = 0.23, p < 0.05). TWIST1 and SIP1 expressions demonstrated a significant correlation (r s = 0.56, p < 0.001). High SIP1 expression was associated with a lower survival rate among ACC cases (p < 0.05). CONCLUSIONS: Vimentin, TWIST1, and SIP1 expressions are increased in aggressive ACT. Therefore, EMT may play a relevant role in adrenal tumorigenesis.

A Novel TP53 Mutation Associated with TWIST1 and SIP1 Expression in an Aggressive Adrenocortical Carcinoma.

Adrenocortical carcinomas (ACC) are very rare tumors related to TP53 mutations mostly in childhood onset cases. Epithelial-mesenchymal transition (EMT) transcription factors TWIST1 and Smad interacting protein 1 (SIP1) are related to poorer outcomes in other malignancies, but their role in ACC is unknown. We describe a case of an advanced metastatic ACC (Weiss-score of 9) in a patient at age 76. After primary tumor resection, mitotane therapy was started as palliation to low-volume liver metastasis. After a 2-year period of stable disease, the patient died due to brain metastasis. Somatic gene sequencing revealed a novel TP53 mutation in DNA extracted from paraffin-embedded tissue, a deletion of 8bp in exon 8 (c.811_818del8; GAGGTGCG/-) in homo or hemizygosis causing a subsequent frameshift and premature stop codon at position 302. Immunohistochemistry of P53 and p-Ser-15 P53 showed absent tumoral staining. In addition, immunohistochemical analysis showed an increased expression of the mesenchymal markers vimentin and fibronectin. At last, EMT transcription factors TWIST1 and SIP1 were also overexpressed in tumoral cells. This case report describes an aggressive ACC with not only a novel somatic mutation, but also a novel International Agency for Research on Cancer database 8 base-pair deletion in TP53 exon 8. In addition, the expression of EMT inducers TWIST1 and SIP1 have been reported for the first time in an ACC case. Further investigation is needed to clarify the biologic significance of this new TP53 mutation and its role in the EMT process.

A Novel Assay for the Identification of NOTCH1 PEST Domain Mutations in Chronic Lymphocytic Leukemia.

Aims. To develop a fast and robust DNA-based assay to detect insertions and deletions mutations in exon 34 that encodes the PEST domain of NOTCH1 in order to evaluate patients with chronic lymphocytic leukemia (CLL). Methods. We designed a multiplexed allele-specific polymerase chain reaction (PCR) combined with a fragment analysis assay to detect specifically the mutation c.7544_7545delCT and possibly other insertions and deletions in exon 34 of NOTCH1. Results. We evaluated our assay in peripheral blood samples from two cohorts of patients with CLL. The frequency of NOTCH1 mutations was 8.4% in the first cohort of 71 unselected CLL patients. We then evaluated a second cohort of 26 CLL patients with known cytogenetic abnormalities that were enriched for patients with trisomy 12. NOTCH1 mutations were detected in 43.7% of the patients with trisomy 12. Conclusions. We have developed a fast and robust assay combining allele-specific PCR and fragment analysis able to detect NOTCH1 PEST domain insertions and deletions.

Phylogenetic relationships within Chamaecrista sect. Xerocalyx (Leguminosae, Caesalpinioideae) inferred from the cpDNA trnE-trnT intergenic spacer and nrDNA ITS sequences

Chamaecrista belongs to subtribe Cassiinae (Caesalpinioideae), and it comprises over 330 species, divided into six sections. The section Xerocalyx has been subjected to a profound taxonomic shuffling over the years. Therefore, we conducted a phylogenetic analysis using a cpDNA trnE-trnT intergenic spacer and nrDNA ITS/5.8S sequences from Cassiinae taxa, in an attempt to elucidate the relationships within this section from Chamaecrista. The tree topology was congruent between the two data sets studied in which the monophyly of the genus Chamaecrista was strongly supported. Our analyses reinforce that new sectional boundaries must be defined in the Chamaecrista genus, especially the inclusion of sections Caliciopsis and Xerocalyx in sect. Chamaecrista, considered here paraphyletic. The section Xerocalyx was strongly supported as monophyletic; however, the current data did not show C. ramosa (microphyllous) and C. desvauxii (macrophyllous) and their respective varieties in distinct clades, suggesting that speciation events are still ongoing in these specimens.

Caracterização molecular de isolados clínicos de Leishmania braziliensis e Leishmania guyanensis e sua associação com a resposta terapêutica ao antimoniato de meglumina no Brasil / Molecular characterization of clinical isolates from Leishmania braziliensis and Leishmania guyanensis and its correlation with the therapeutic response to meglumine antimoniate in Brazil

No Brasil, a leishmaniose cutânea (LC) constitui um importante problema de saúde pública, apresentando cerca de 28.000 novos casos reportados anualmente pelo Ministério da Saúde. Sete espécies de Leishmania causam a LC no Brasil, no qual a L. braziliensis e a L. guyanensis aparentam ser as mais prevalentes. Nos últimos anos, vêm sendo reportados casos clínicos que não respondem ao tratamento. O fenômeno de falha terapêutica é complexo e dentre os vários fatores envolvidos está o fenótipo de resistência a drogas no parasito. Portanto, é fundamental identificar marcadores moleculares relacionados à resposta terapêutica ao antimoniato de meglumina na LC causada por isolados de L. braziliensis e L. guyanensis no Brasil. Neste estudo analisou-se isolados de L. braziliensis e L. guyanensis obtidos de pacientes com diferentes respostas terapêuticas, observando o polimorfismo das seqüências de DNA de regiões referentes aos genes AQP1, HSP70, MRPA e TR. Além disso, através da técnica de PCR em tempo real quantitativo, realizou-se uma análise do perfil de expressão de quatro genes alvo que codificam proteínas com função de transporte (AQP1 e MRPA) e metabolismo óxido-redutor (gama-GCS e TR). A variabilidade das seqüências estudadas sugere que L. braziliensis é mais heterogênea que L. gutanensis, corroborando com estudos anteriores. Uma análise de agrupamento hierárquico não revelou uma associação da resposta terapêutica com as seqüências em estudo. Através de um modelo de regressão logística múltiplo foi observado um polimorfismo na posição 1735 do gene HSP70 com chance 7,3 vezes maior de que isolados de L. braziliensis que apresentem uma guanina ao invés de uma adenina estejam associados à falha terapêutica. Também, foram observadas várias mutações não sinônimas nos genes em estudo que podem promover alterações na estrutura e atividade da proteína e, portanto, estarem relacionadas ao fenótipo de resistência a drogas em Leishmania. O perfil de expressão gênica observado revelou que a diferença entre as fases de crescimento de promastigotas em estudo não foi informativo. Então, considerando-se apenas a espécie e a resposta terapêutica, foi observado que o gene y-GCS está superexpresso em isolados de falha terapêutica em L. guyanensis, indicando o potencial deste gene para ser utilizado no prognóstico da leishmaniose cutânea. Portanto, o presente trabalho enaltece que a diversidade fenotípica em Leishmania está além das informações presentes no genoma, podendo ser em parte explicada pelos diferentes níveis de expressão gênica observado entre os parasitos.