Hox genes control homocercal caudal fin development and evolution.

Ancient bony fishes had heterocercal tails, like modern sharks and sturgeons, with asymmetric caudal fins and a vertebral column extending into an elongated upper lobe. Teleost fishes, in contrast, developed a homocercal tail characterized by two separate equal-sized fin lobes and the body axis not extending into the caudal fin. A similar heterocercal-to-homocercal transition occurs during teleost ontogeny, although the underlying genetic and developmental mechanisms for either transition remain unresolved. Here, we investigated the role of hox13 genes in caudal fin formation as these genes control posterior identity in animals. Analysis of expression profiles of zebrafish hox13 paralogs and phenotypes of CRISPR/Cas9-induced mutants showed that double hoxb13a and hoxc13a mutants fail to form a caudal fin. Furthermore, single mutants display heterocercal-like morphologies not seen since Mesozoic fossil teleosteomorphs. Relaxation of functional constraints after the teleost genome duplication may have allowed hox13 duplicates to neo- or subfunctionalize, ultimately contributing to the evolution of a homocercal tail in teleost fishes.

Potential role of exitron-containing homeobox genes in cancer.

Homeobox genes are protagonists in developmental and cancer biology, making comprehending their regulation pivotal in multiple molecular pathways. Exitrons, also known as intronic exons, are new players in the transcriptional organization, providing additional splicing variants whose functions are still vastly unknown. Exitron splicing sites were identified in eight homeobox genes, which has not been yet debated in the scientific literature. Due to the intimate connection between homeobox genes and tumorigenesis, it is worth investing more time in understanding how these less explored exitron-containing transcriptional isoforms could play a role in modulating the homeobox gene's biological functions. The perspectives devised in this article are meant to instigate fresh debates on how the transcriptional variants retaining exitrons identified in the human homeobox genes HOXA1, HOXA9, HOXD8, NKX3.1, and DLX6 can be examined in the context of tumorigenesis. This article is categorized under: Cancer > Genetics/Genomics/Epigenetics.

Zinc fingers and homeoboxes 2 inhibition could suppress the proliferation of ovarian cancer cells by apoptosis pathway.

OBJECTIVE: The Zinc fingers and homeoboxes (ZHX) protein family has been reported to be involved in tumor development; however, it remains controversial whether these proteins can act as promoters or inhibitors of cancer development. The current study focused on the biological role of ZHX2 in ovarian cancer. METHODS: Tissue microarrays were established using 154 ovarian cancer samples. Immunohistochemical analysis was employed to determine the expression levels of ZHX2 in ovarian cancer samples. The prognostic analysis was performed using the Kaplan-Meier method and compared with a log-rank test. The specific role of ZHX2 in ovarian cancer was investigated in cell lines in vitro. RESULTS: It was found that ZHX2 was not significantly overexpressed in ovarian cancer samples; however, its expression was significantly correlated with advanced tumor grade. Patient survival analysis indicated that patients with high expression of ZHX2 exhibited worse overall survival rate compared with those with low expression of ZHX2. Furthermore, univariate and multivariate analyses demonstrated that ZHX2 was an independent prognostic factor of progression-free survival in patients with ovarian cancer. In vitro experiments indicated that inhibition of ZHX2 could significantly suppress ovarian cancer cell proliferation via induction of the apoptotic pathway. CONCLUSIONS: The data indicated that ZHX2 may be considered a promising biomarker in ovarian cancer and that inhibition of its expression may be a potential therapeutic target in ovarian cancer treatment.

Variants Identified in the HOXC13 and HOXD13 Genes Suggest Association with Cervical Cancer in a Cohort of Mexican Women.

HOX genes have been associated with carcinogenesis. However, the molecular mechanism by which tumors are generated remains unclear. The HOXC13 and HOXD13 genes are of interest for their involvement in the development of genitourinary structures. The aim of this first study in the Mexican population was to search for and analyze variants in the coding region of the HOXC13 and HOXD13 genes in women with cervical cancer. Samples from Mexican women with cervical cancer and healthy women were sequenced (50/50). Allelic and genotypic frequencies were compared between groups. The functional impact of the proteins was determined with two bioinformatics servers (SIFT and PolyPhen-2), and the oncogenic potential of the identified nonsynonymous variants was determined using the CGI server. We identified five unreported gene variants: c.895C>A p.(Leu299Ile) and c.777C>T p.(Arg259Arg) in the HOXC13 gene and c.128T>A p.(Phe43Tyr), c.204G>A p.(Ala68Ala), and c.267G>A p.(Ser89Ser) in the HOXD13 gene. In this study, we suggest that the non-synonymous variants c.895C>A p.(Leu299Ile) and c.128T>A p.(Phe43Tyr) could represent a risk factor for the development of the disease, although additional studies in larger patient populations and in different ethnic groups are needed in order to support the results observed.

Micro ribonucleic acid-448 regulates zinc finger e-box binding homeobox 1 to inhibit the growth of breast cancer cells and increase their sensitivity to chemotherapy.

OBJECTIVE: This study aimed to investigate the effect of Zinc Finger E-box Binding Homeobox 1 (ZEB1) regulation by Micro Ribonucleic acid (miR)-448 on Breast Cancer (BC) cells and their sensitivity to chemotherapy. METHODS: miR-448 and ZEB1 mRNA levels in BC and normal tissues were detected by qPCR, and ZEB1 protein was detected by Western Blotting (WB). The correlation between miR-448 and tumor metastasis, clinical staging, and ZEB1 expression was analyzed. MCF-7 cells were transfected or co-transfected with the miR-448 mimic, oe-ZEB1, or their negative controls. Changes in miR-448 and ZEB1 expression were detected by qPCR and WB. Cell proliferation was determined by CCK-8 assays, invasion changes were analyzed by Transwell assays, and apoptosis was detected by flow cytometry. RESULTS: miR-448 expression in BC tissues was lower than that in normal tissues, while ZEB1 expression was increased in the former. ZEB1 expression was lower in BC patients with lymph node metastasis than in those without. In patients with clinical stage I-III BC, miR-448 expression decreased with an increase in tumor stage, which was negatively correlated with ZEB1 expression. Upregulation of miR-448 expression can suppress MCF-7 cell proliferation and invasion and promote apoptosis. Upregulation of ZEB1 expression in cells overexpressing miR-448 can partially reverse the inhibition of BC cell growth induced by miR-448. miR-448 can enhance the sensitivity of cells toward paclitaxel and 5-fluorouracil. CONCLUSIONS: miR-448 suppresses cell proliferation and invasion and promotes apoptosis by targeting ZEB1. Moreover, it can increase the sensitivity of cells toward paclitaxel and 5-fluorouracil.

Identification of Hox genes and their expression profiles during embryonic development of the emerging model organism, Macrobrachium olfersii.

Hox genes encode transcription factors that specify the body segment identity during development, including crustaceans, such as amphipods and decapods, that possess a remarkable diversity of segments and specialized appendages. In amphipods, alterations of specialized appendages have been obtained using knockout experiment of Hox genes, which suggests that these genes are involved in the evolution of morphology within crustaceans. However, studies of Hox genes in crustaceans have been limited to a few species. Here, we identified the homeodomain of nine Hox genes: labial (lab), proboscipedia (pb), Deformed (Dfd), Sex combs reduced (Scr), fushi tarazu (ftz), Antennapedia (Antp), Ultrabithorax (Ubx), abdominal-A (abdA), and Abdominal-B (AbdB), and evaluated their expression by RT-qPCR and RT-PCR in the ovary, during embryonic development, and at the first larval stage (Zoea I) of the decapod Macrobrachium olfersii. The transcript levels of lab, Dfd, and ftz decreased and transcripts of pb, Scr, Antp, Ubx, abdA, and AbdB increased during embryonic development. Hox genes were expressed in mature ovaries and Zoea I larval stages, except Scr and ftz, respectively. In addition, isoforms of Dfd, Scr, Ubx, and abdA, which have been scarcely reported in crustaceans, were described. New partial sequences of 87 Hox genes from other crustaceans were identified from the GenBank database. Our results are interesting for future studies to determine the specific function of Hox genes and their isoforms in the freshwater prawn M. olfersii and to contribute to the understanding of the diversity and evolution of body plans and appendages in Crustaceans.

Upregulation of HOX genes promotes cell migration and proliferation in head and neck squamous cell carcinoma.

BACKGROUND: Expression dysregulation of HOX homeobox genes has been observed in several cancers, including head and neck squamous cell carcinoma (HNSC). Although characterization of HOX gene roles in HNSC development has been reported, there is still a need to better understand their real contribution to tumorigenesis. OBJECTIVE: The present study aimed to evaluate the contribution of the protein-coding HOX genes (HOXA10, HOXC9, HOXC10, and HOXC13) in cellular processes related to carcinogenesis and progression of the HNSC. METHODS: Expression of HOX genes was analyzed in HNSC RNA-Seq data from The Cancer Genome Atlas (TCGA) and by RT-qPCR in different tumor cell lines. siRNA-mediated knockdown of HOXA10, HOXC9, HOXC10 or HOXC13 was performed in HNSC cell lines, and predicted transcriptional targets HOX genes was analyzed by bioinformatic. RESULTS: Thirty-one out of the 39 mammalian HOX genes were found upregulated in HNSC tissues and cell lines. The HOXC9, HOXC10 or HOXC13 knockdown attenuated cell migration, and lead to downregulation of epithelial-mesenchymal transition (EMT) markers, which were predicted as transcriptional targets of these three HOX genes. Diminished colony formation and cell cycle arrest after HOXC10 or HOXC13 knockdown were also observed, corroborating the fact that there was an enrichment for genes in proliferation/cell cycle pathways. CONCLUSIONS: In summary, we revealed roles for HOXC9, HOXC10, and HOXC13 in cell migration and proliferation/cell cycle progression in HNSC cells and suggested that those HOX members contribute to HNSC development possibly by regulating tumor growth and metastasis.

Homeobox gene amplification and methylation in oral squamous cell carcinoma.

OBJECTIVES: Investigate the DNA copy number and the methylation profile of the homeobox genes HOXA5, HOXA7, HOXA9, HOXB5, HOXB13, HOXC12, HOXC13, HOXD10, HOXD11, IRX4 and ZHX1, and correlate them with clinicopathological parameters and overall survival. MATERIAL AND METHODS: DNA from OSCC samples and surgical margins were submitted to DNA amplification by qPCR and to DNA methylation analysis using a DNA Methylation PCR Array System. RESULTS: HOXA5, HOXB5 and HOXD10 were amplified in surgical margins while HOXA9, HOXB13 and IRX4 were amplified in OSCC. HOXD10 demonstrated hypermethylation in half of the tumor while ZHX1 did not show hypermethylation. No correlation of DNA copy number or methylation with clinicopathological parameters or survival was observed. CONCLUSION: HOXA9, HOXB13 and IRX4 genes appears to be regulated by amplification and HOXD10 by methylation in OSCC. Further studies are needed to determine the role of these events in OSCC development.

ZNF718, HOXA4, and ZFP57 are differentially methylated in periodontitis in comparison with periodontal health: Epigenome-wide DNA methylation pilot study.

OBJECTIVE: To investigate the differences in the epigenomic patterns of DNA methylation in peripheral leukocytes between patients with periodontitis and gingivally healthy controls evaluating its functional meaning by functional enrichment analysis. BACKGROUND: The DNA methylation profiling of peripheral leukocytes as immune-related tissue potentially relevant as a source of biomarkers between periodontitis patients and gingivally healthy subjects has not been investigated. METHODS: A DNA methylation epigenome-wide study of peripheral leukocytes was conducted using the Illumina MethylationEPIC platform in sixteen subjects, eight diagnosed with periodontitis patients and eight age-matched and sex-matched periodontally healthy controls. A trained periodontist performed the clinical evaluation. Global DNA methylation was estimated using methylation-sensitive high-resolution melting in LINE1. Routine cell count cytometry and metabolic laboratory tests were also performed. The analysis of differentially methylated positions (DMPs) and differentially methylated regions (DMRs) was made using R/Bioconductor environment considering leukocyte populations assessed in both routine cell counts and using the FlowSorted.Blood.EPIC package. Finally, a DMP and DMR intersection analysis was performed. Functional enrichment analysis was carried out with the differentially methylated genes found in DMP. RESULTS: DMP analysis identified 81 differentially hypermethylated genes and 21 differentially hypomethylated genes. Importantly, the intersection analysis showed that zinc finger protein 718 (ZNF718) and homeobox A4 (HOXA4) were differentially hypermethylated and zinc finger protein 57 (ZFP57) was differentially hypomethylated in periodontitis. The functional enrichment analysis found clearly immune-related ontologies such as "detection of bacterium" and "antigen processing and presentation." CONCLUSION: The results of this study propose three new periodontitis-related genes: ZNF718, HOXA4, and ZFP57 but also evidence the suitability and relevance of studying leukocytes' DNA methylome for biological interpretation of systemic immune-related epigenetic patterns in periodontitis.

Delineating the anuran axial skeleton.

The axial skeleton of the anurans has undergone an evolutionary reduction of its bone elements. This structural plan is strongly preserved throughout the order and would have emerged as a highly specialized anatomical adaptation to its locomotor jumping pattern. The development programs that direct the vertebral morphogenesis of the anurans are poorly described and the molecular bases that have caused their pattern to differ from other tetrapods are completely unknown. In this work, we review the ontogeny of the spinal column of the anurans and explore the genetic mechanisms that could explain the morphological difference and the maintenance of the body plan during evolution. Here, we propose that the absence of caudal osseous elements, as a consequence of the inability of sclerotomes to form cartilaginous condensations in frogs, could be due to changes in both pattern and expression levels of Hox, Pax1, Pax9 and Uncx4.1 genes along the anteroposterior axis. The anteriorised expression of the Hox genes together with the reduction in the expression levels of Pax1, Pax9 and Uncx4 in the posterior somites could explain, at least partly, the loss of caudal vertebrae in the anurans during evolution.

Homeobox B2 is a potential prognostic biomarker of glioblastoma.

OBJECTIVES HOXB2 is a new prognostic indicator for lung cancer. But it is unclear whether HOXB2 holds an effect in glioblastoma (GBM) progression. The purpose of this article was to probe the influences of HOXB2 on GBM pathogenesis. METHODS HOXB2 expression level and prognostic power in GBM patients were analyzed. Then the mRNA and protein expression levels of HOXB2 in GBM cell lines were tested by qRT-PCR and western blotting. Cell proliferation, invasion, and migration were determined by CCK8 and transwell assay, severally. The protein levels of PI3K/AKT-pathway associated proteins were analyzed by western blotting. RESULTS The results indicated that HOXB2 was distinctly overexpressed in GBM patients and high expression of HOXB2 was related to a poor prognosis. Moreover, the expression of HOXB2 was higher in all GBM cell lines U251, U-87MG, GOS-3 than that in HEB cells (normal control). Meanwhile, decreased expression of p-PI3K and p-AKT were identified after HOXB2 knockdown. CONCLUSIONS These data demonstrated that HOXB2 had a vital role in GBM progression and could serve as a promising target for GBM treatment.

Homeobox B2 is a potential prognostic biomarker of glioblastoma

SUMMARY OBJECTIVES HOXB2 is a new prognostic indicator for lung cancer. But it is unclear whether HOXB2 holds an effect in glioblastoma (GBM) progression. The purpose of this article was to probe the influences of HOXB2 on GBM pathogenesis. METHODS HOXB2 expression level and prognostic power in GBM patients were analyzed. Then the mRNA and protein expression levels of HOXB2 in GBM cell lines were tested by qRT-PCR and western blotting. Cell proliferation, invasion, and migration were determined by CCK8 and transwell assay, severally. The protein levels of PI3K/AKT-pathway associated proteins were analyzed by western blotting. RESULTS The results indicated that HOXB2 was distinctly overexpressed in GBM patients and high expression of HOXB2 was related to a poor prognosis. Moreover, the expression of HOXB2 was higher in all GBM cell lines U251, U-87MG, GOS-3 than that in HEB cells (normal control). Meanwhile, decreased expression of p-PI3K and p-AKT were identified after HOXB2 knockdown. CONCLUSIONS These data demonstrated that HOXB2 had a vital role in GBM progression and could serve as a promising target for GBM treatment.

RESUMO OBJETIVOS A HOXB2 é um novo indicador prognóstico para o câncer de pulmão. Mas não está claro se a HOXB2 tem algum efeito na progressão do glioblastoma (GBM). O objetivo deste artigo foi sondar as influências da HOXB2 na patogênese do GBM. MÉTODOS Foram analisados o nível de expressão e o poder prognóstico da HOXB2 em pacientes com GBM. Em seguida, os níveis de expressão proteica e mRNA da HOXB2 em linhagens de células de GBM foram testados por qRT-PCR e western blotting. A proliferação, a invasão e migração celular foram determinadas por CCK8 e ensaios transwell, várias vezes. Os níveis proteicos das proteínas associadas à via PI3K/AKT foram analisados pelo método western blotting. RESULTADOS Os resultados indicaram que havia uma clara superrexpressão da HOXB2 em pacientes com GBM e que a alta expressão da HOXB2 estava relacionada a um prognóstico negativo. Além disso, a expressão da HOXB2 foi mais elevada em todas as linhagens de células do GBM U251, U-87MG, GOS-3 do que nas células HEB (controle normal). Entretanto, a diminuição da expressão de P-PI3K e p-AKT foi identificada após a redução da expressão da HOXB2. CONCLUSÕES Esses dados demonstram que a HOXB2 desempenha um papel vital na progressão do GBM, podendo ser um alvo promissor para o tratamento do GBM.

Contributions of HOX genes to cancer hallmarks: Enrichment pathway analysis and review.

Homeobox genes function as master regulatory transcription factors during development, and their expression is often altered in cancer. The HOX gene family was initially studied intensively to understand how the expression of each gene was involved in forming axial patterns and shaping the body plan during embryogenesis. More recent investigations have discovered that HOX genes can also play an important role in cancer. The literature has shown that the expression of HOX genes may be increased or decreased in different tumors and that these alterations may differ depending on the specific HOX gene involved and the type of cancer being investigated. New studies are also emerging, showing the critical role of some members of the HOX gene family in tumor progression and variation in clinical response. However, there has been limited systematic evaluation of the various contributions of each member of the HOX gene family in the pathways that drive the common phenotypic changes (or "hallmarks") and that underlie the transformation of normal cells to cancer cells. In this review, we investigate the context of the engagement of HOX gene targets and their downstream pathways in the acquisition of competence of tumor cells to undergo malignant transformation and tumor progression. We also summarize published findings on the involvement of HOX genes in carcinogenesis and use bioinformatics methods to examine how their downstream targets and pathways are involved in each hallmark of the cancer phenotype.

Expressão gênica e proteica de membros da família HOX no câncer de mama luminal / Gene and protein expression of HOX family members in luminal breast cancer

Os genes homeobox são fatores de transcrição que regulam a expressão de múltiplos genes que influenciam o crescimento celular e fazem a mediação entre o epitélio e o estroma, regulando a diferenciação específica de cada tecido. Sua expressão é comumente desregulada em tumores, e estudos indicam que estes genes atuam como oncogenes, promovendo crescimento celular e invasão, ou como supressores tumorais, devido à sua atuação nos processos de morfogênese. No caso do câncer de mama, alguns genes homeobox tem expressão aumentada e outros, reduzida, e em geral não há ocorrência de mutações. Objetivos: Este trabalho procurou estudar a expressão de membros da família HOX em carcinomas luminais da mama, e correlacionar essa expressão com características clínico-patológicas, sobrevida global e livre de doença; avaliar a correlação entre a expressão de HOXA1 e Receptor de Progesterona; avaliar a correlação da expressão de HOXB7 e de MYC, bem como comparar os resultados da expressão gênica por imunohistoquímica e RT-qPCR. Métodos: Foram selecionados 260 pacientes com Carcinoma Mamário Luminal (CML) diagnosticados entre 2007 e 2010, 29 pacientes com amostras de CML congelados no Biobanco do AC Camargo Cancer Center, todos pareados com as respectivas amostras para imunohistoquímica, e 4 casos de tecido mamário normal congelado oriundos das pacientes doadoras de amostras de tumor congeladas. A expressão gênica foi pesquisada através dos métodos de imunohistoquímica e reação em cadeia da polimerase da transcrição reversa em tempo real. A técnica imunohistoquímica e os ensaios de expressão gênica foram realizados para os genes HOXA1, HOXA5, HOXA9, HOXB7, HOXB9, HOXB13, HOXC13 e HOXD3. Para a técnica de imunohistoquímica, o número de células positivas foi quantificado para cada marcador através do sistema de morfometria e escaneamento de lâminas Aperio ScanScope XT. A quantificação relativa de expressão gênica, na técnica de RT-qPCR foi realizada utilizando o software Sequence Detection System (Applied Biosystems), e calculada pelo modelo matemático descrito por Pfaffl. Todos os testes estatísticos foram realizados utilizando os softwares Excel (Microsoft 2011) e IBM SPSS, versão 24. Resultados: Houve associação com entre a expressão de HOXB7 e estadiamento patológico T ao diagnóstico (p=0,015) e entre a expressão de HOXC13 e estadiamento N ao diagnóstico (p=0,002; OR=2,61). Aumento da expressão de HOXA9 foi associado com redução da sobrevida global (p=0,031; RR: 2,331, IC95% [1,054-5,157], P=0,037). Não houve associação entre a expressão de HOXA1 e Receptor de Progesterona e/ou entre a expressão de HOXB7 e MYC. A correlação entre a expressão gênica por imunohistoquímica e RT-qPCR foi inexistente, negativa fraca ou positiva muito fraca. Conclusões: Aumento da expressão de HOXB7 é associado com pior estadiamento patológico T ao diagnóstico. Aumento da expressão de HOXC13 é associado com maior ocorrência de metástases linfonodais. Aumento da expressão de HOXA9 reduz a sobrevida global

Homeobox genes are transcription factors that regulate the expression of multiple genes which affect cell growth and make the mediation between the epithelium and the stroma, so regulating the differentiation of each specific tissue. Its expression is commonly deregulated in tumors, and studies indicate that these genes act as oncogenes, promoting cell growth and invasion, or act as tumor suppressors genes, due to its role in morphogenesis processes. In breast cancer, homeobox genes can have their increased or decreased expression, and generally there are no ocurrence of mutations. Objectives: This work aimed to study the expression of HOX family members in luminal carcinomas of the breast and to correlate this expression with clinical-pathological characteristics, global and disease-free survival; to evaluate the correlation between the expression of HOXA1 and Progesterone Receptor; to evaluate the correlation of HOXB7 and MYC expression, as well as to compare the results of the gene expression by immunohistochemistry and RT-qPCR. Methods: We selected 260 patients with Luminal Mammary Carcinoma (CML) diagnosed between 2007 and 2010, 29 patients with frozen CML samples in the AC Camargo Cancer Center Biobank, all paired with the respective samples for immunohistochemistry, and 4 cases of normal breast tissue frozen from donor patients with frozen tumor samples. Gene expression was investigated through the immunohistochemistry and reverse transcription polymerase chain reaction in real time. Immunohistochemical technique and gene expression assays were performed for the genes HOXA1, HOXA5, HOXA9, HOXB7, HOXB9, HOXB13, HOXC13 and HOXD3. For the immunohistochemical technique, the number of positive cells was quantified for each marker through the morphometry and scanning system of Aperio ScanScope XT slides. The relative quantification of gene expression in the RT-qPCR technique was performed using the Sequence Detection System (Applied Biosystems) software, and calculated by the mathematical model described by Pfaffl. Results: There was an association between the expression of HOXB7 and pathological staging T at the diagnosis (p = 0.015) and between the expression of HOXC13 and staging N at diagnosis (p = 0.002, OR = 2.61). Increased expression of HOXA9 was associated with a reduction in overall survival (p = 0.031, RR = 2.331, 95% CI [1.054-5.157], P = 0.037). There was no association between the expression of HOXA1 and Progesterone Receptor and / or between the expression of HOXB7 and MYC. The correlation between the gene expression by immunohistochemistry and RT-qPCR was non-existent, negative negative or very weak positive. Conclusions: Increased expression of HOXB7 is associated with poorer T staging at diagnosis. Increased expression of HOXB13 is associated with increased occurrence of lymph node metastases. Increased expression of HOXA9 reduces overall survival

Avaliação da expressão dos genes homeobox em células de carcinoma mucoepidermoide tratadas com cisplatina / Evaluation of homeobox gene expression in cisplatin-treated mucoepidermoid carcinoma cells

O carcinoma mucoepidermoide (CME) é a neoplasia maligna de glândula salivar mais comum, e com maior frequência de metástase linfonodal. Alterações genéticas estão intimamente associadas à carcinogênese e, também, aos processos de metástase tumoral. Para o CME o tratamento de escolha mais aplicado hoje é a cirurgia seguida de radioterapia, pois a quimioterapia não tem mostrado muita eficiência para o tratamento destas neoplasias. Entre os quimioterápicos mais prescritos para o tratamento de cânceres encontra-se a cisplatina, à base de platina, que atua no DNA da célula, induzindo a apoptose. Pouco se sabe a respeito de seu mecanismo de ação sobre o CME, inclusive sobre os genes homeobox. Estes genes compreendem uma família grande e essencial de reguladores do desenvolvimento que são vitais para o crescimento e diferenciação celular, e a expressão anômala destes genes têm sido implicados na carcinogênese. Assim, este trabalho teve como objetivo avaliar a expressão dos genes homeobox em células derivadas de carcinoma mucoepidermoide tratadas com cisplatina. Os genes avaliados neste trabalho foram: PROX1, MEIS1, HOXB5, HOXB7 e HOXB9 por RT-qPCR. Previamente, as linhagens celulares derivadas de carcinoma mucoepidermoide UM-HMC1 UM-HMC2 e UM-HMC3A foram tratadas com a cisplatina por 24h e posteriormente submetidas aos ensaios de RT-qPCR. Adicionalmente, as amostras tratadas e sem tratamento foram analisadas pelo ensaio de formação de esferas e ensaio de ferida para verificar o efeito da cisplatina sobre propriedades relacionadas às células quimiorresistentes (putativas células tronco tumorais). Como resultados, entre os genes analisados foram expressos PROX1, MEIS1 e HOXB7. A UM-HMC3A apresentou maior expressão destes genes que as demais linhagens. Os genes HOXB5 e HOXB9 não foram expressos nas linhagens analisadas. A cisplatina reduziu a expressão de MEIS1 e aumentou a expressão de HOXB7, em todas as linhagens. O gene PROX1 apresentou expressão variável entre as linhagens, sendo expresso na UM-HMC1 apenas quando são tratadas com cisplatina e reduzido nas UM-HMC2 e UM-HMC3A tratadas. O número de esferas formadas não apresentou diferença significativa para UM-HMC1 e UM-HMC3A, o número de esferas aumentou na linhagem UM-HMC2 tratada com cisplatina. No ensaio de ferida, a cisplatina foi capaz de reduzir a migração celular em todas as linhagens quando comparadas com seus controles. Os resultados sugerem que o PROX1 e HOXB7 podem estar relacionados com carcinomas mucoepidermoides mais invasivos, enquanto que o MEIS1 pode estar relacionado à carcinogênese e autorrenovação tumoral. A cisplatina é capaz de afetar a expressão dos genes homeobox PROX1, MEIS1 e HOXB7, os quais foram encontrados nas linhagens de carcinoma mucoepidermoide analisados. A cisplatina não afeta as células formadoras de esferas, mas reduzir a migração das linhagens de carcinoma mucoepidermoide.

Methylation status of homeobox genes in common human cancers.

Approximately 300 homeobox loci were identified in the euchromatic regions of the human genome, of which 235 are probable functional genes and 65 are likely pseudogenes. Many of these genes play important roles in embryonic development and cell differentiation. Dysregulation of homeobox gene expression is a frequent occurrence in cancer. Accumulating evidence suggests that as genetics disorders, epigenetic modifications alter the expression of oncogenes and tumor suppressor genes driving tumorigenesis and perhaps play a more central role in the evolution and progression of this disease. Here, we described the current knowledge regarding homeobox gene DNA methylation in human cancer and describe its relevance in the diagnosis, therapeutic response and prognosis of different types of human cancers.

HOX genes: potential candidates for the progression of laryngeal squamous cell carcinoma.

Laryngeal squamous cell carcinoma (LSCC) is a very aggressive cancer, considered to be a subtype of the head and neck squamous cell carcinoma (HNSCC). Despite significant advances in the understanding and treatment of cancer, prognosis of patients with LSCC has not improved recently. In the present study, we sought to understand better the genetic mechanisms underlying LSCC development. Thirty-two tumor samples were collected from patients undergoing surgical resection of LSCC. The samples were submitted to whole-genome cDNA microarray analysis aiming to identify genetic targets in LSCC. We also employed bioinformatic approaches to expand our findings using the TCGA database and further performed functional assays, using human HNSCC cell lines, to evaluate viability, cell proliferation, and cell migration after silencing of selected genes. Eight members of the homeobox gene family (HOX) were identified to be overexpressed in LSCC samples when compared to normal larynx tissue. Quantitative RT-PCR analysis validated the overexpression of HOX gene family members in LSCC. Receiver operating characteristic (ROC) statistical method curve showed that the expression level of seven members of HOX gene family can distinguish tumor from nontumor tissue. Correlation analysis of clinical and gene expression data revealed that HOXC8 and HOXD11 genes were associated with the differentiation degree of tumors and regional lymph node metastases, respectively. Additionally, siRNA assays confirmed that HOXC8, HOXD10, and HOXD11 genes might be critical for cell colony proliferation and cell migration. According to our findings, several members of the HOX genes were overexpressed in LSCC samples and seem to be required in biological processes involved in tumor development. This suggests that HOX genes might play a critical role in the physiopathology of LSCC tumors.

Selection on different genes with equivalent functions: the convergence story told by Hox genes along the evolution of aquatic mammalian lineages.

BACKGROUND: Convergent evolution has been a challenging topic for decades, being cetaceans, pinnipeds and sirenians textbook examples of three independent origins of equivalent phenotypes. These mammalian lineages acquired similar anatomical features correlated to an aquatic life, and remarkably differ from their terrestrial counterparts. Whether their molecular evolutionary history also involved similar genetic mechanisms underlying such morphological convergence nevertheless remained unknown. To test for the existence of convergent molecular signatures, we studied the molecular evolution of Hox genes in these three aquatic mammalian lineages, comparing their patterns to terrestrial mammals. Hox genes are transcription factors that play a pivotal role in specifying embryonic regional identity of nearly any bilateral animal, and are recognized major agents for diversification of body plans. RESULTS: We detected few signatures of positive selection on Hox genes across the three aquatic mammalian lineages and verified that purifying selection prevails in these sequences, as expected for pleiotropic genes. Genes found as being positively selected differ across the aquatic mammalian lineages, but we identified a substantial overlap of their developmental functions. Such pattern likely resides on the duplication history of Hox genes, which probably provided different possible evolutionary routes for achieving the same phenotypic solution. CONCLUSIONS: Our results indicate that convergence occurred at a functional level of Hox genes along three independent origins of aquatic mammals. This conclusion reinforces the idea that different changes in developmental genes may lead to similar phenotypes, probably due to the redundancy provided by the participation of Hox paralogous genes in several developmental functions.