Gene Summary

Gene:HOXA5; homeobox A5
Aliases: HOX1, HOX1C, HOX1.3
Summary:In vertebrates, the genes encoding the class of transcription factors called homeobox genes are found in clusters named A, B, C, and D on four separate chromosomes. Expression of these proteins is spatially and temporally regulated during embryonic development. This gene is part of the A cluster on chromosome 7 and encodes a DNA-binding transcription factor which may regulate gene expression, morphogenesis, and differentiation. Methylation of this gene may result in the loss of its expression and, since the encoded protein upregulates the tumor suppressor p53, this protein may play an important role in tumorigenesis. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:homeobox protein Hox-A5
Source:NCBIAccessed: 31 August, 2019


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: HOXA5 (cancer-related)

Pineda B, Diaz-Lagares A, Pérez-Fidalgo JA, et al.
A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer patients.
Clin Epigenetics. 2019; 11(1):33 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) varies between 30 and 40% approximately. To provide further insight into the prediction of pCR, we evaluated the role of an epigenetic methylation-based signature.
METHODS: Epigenetic assessment of DNA extracted from biopsy archived samples previous to NAC from TNBC patients was performed. Patients included were categorized according to previous response to NAC in responder (pCR or residual cancer burden, RCB = 0) or non-responder (non-pCR or RCB > 0) patients. A methyloma study was performed in a discovery cohort by the Infinium HumanMethylation450 BeadChip (450K array) from Illumina. The epigenetic silencing of those methylated genes in the discovery cohort were validated by bisulfite pyrosequencing (PyroMark Q96 System version 2.0.6, Qiagen) and qRT-PCR in an independent cohort of TN patients and in TN cell lines.
RESULTS: Twenty-four and 30 patients were included in the discovery and validation cohorts, respectively. In the discovery cohort, nine genes were differentially methylated: six presented higher methylation in non-responder patients (LOC641519, LEF1, HOXA5, EVC2, TLX3, CDKL2) and three greater methylation in responder patients (FERD3L, CHL1, and TRIP10). After validation, a two-gene (FER3L and TRIP10) epigenetic score predicted RCB = 0 with an area under the ROC curve (AUC) = 0.905 (95% CI = 0.805-1.000). Patients with a positive epigenetic two-gene score showed 78.6% RCB = 0 versus only 10.7% RCB = 0 if signature were negative.
CONCLUSIONS: These results suggest that pCR in TNBC could be accurately predicted with an epigenetic signature of FERD3L and TRIP10 genes. Further prospective validation of these findings is warranted.

Chen YQ, Yang TQ, Zhou B, et al.
HOXA5 overexpression promotes osteosarcoma cell apoptosis through the p53 and p38α MAPK pathway.
Gene. 2019; 689:18-23 [PubMed] Related Publications
Osteosarcoma is the most common malignant bone tumor in children and adolescents. Aberrant expression of HOXA5 results in various diseases, including cancers. However, the specific function and molecular mechanism of HOXA5 in osteosarcoma is not fully understood. In the present study, we focused on HOXA5 in U2OS and MG63 cells in vitro. We observed lower expression of HOXA5 in U2OS, MG63, and SaOS2 human osteosarcoma cells, compared with hFOB1.19 human osteoblastic cells. HOXA5 overexpression in U2OS and MG63 cells markedly reduced cell survival and proliferation and elevated cell apoptosis and caspase-3 activity. HOXA5 also activated the p38α MAPK pathway by increasing p53. Treating U2OS and MG63 cells with the p53 inhibitor α-pifithrin or the p38α MAPK inhibitor SB203580 led to higher cell survival and proliferation and lower cell apoptosis, compared with the pcDNA3.1-HOXA5 group. In conclusion, our study showed that the p53 and p38α MAPK signal axis facilitated HOXA5's role in inhibiting growth and stimulating apoptosis of osteosarcoma cells.

Wang Z, Yu C, Wang H
HOXA5 inhibits the proliferation and induces the apoptosis of cervical cancer cells via regulation of protein kinase B and p27.
Oncol Rep. 2019; 41(2):1122-1130 [PubMed] Related Publications
Homeobox A5 (HOXA5) is a member of the homeobox gene (HOX) family, which plays an important role in the development of various malignant tumors. Here, we speculated that HOXA5 has an effect on cervical cancer development. In our study, we aimed to explore the role and molecular mechanism of HOXA5 in regards to the cell proliferation and apoptosis in cervical cancer. We found that expression levels of HOXA5 measured by RT‑qPCR and western blot assays in cervical cancer cell lines and tissues were both significantly downregulated. We performed a gain‑of‑function experiment by the transfection with pcDNA.3.1‑HOXA5 in ME‑180 and HT‑3 cells to overexpress HOXA5, and the caspase‑3 activity measured by caspase‑3 activity assay kit and cell apoptosis detected by flow cytometry were obviously promoted. Meanwhile, cell proliferation tested by BrdU assay, invasion determined by Transwell and cell viability tested by MTT were inhibited. Moreover, protein kinase B (AKT) was activated by incubation with SC79 (AKT activator; 1 µg/ml) after HOXA5 overexpression, and reversed the effect of HOXA5 overexpression on p27 expression. Additionally, significant elevation of AKT activation measured by western blot analysis abrogated the effect of HOXA5 on caspase‑3 activity, cell apoptosis, proliferation, invasion and cell viability. Taken together, this study revealed that HOXA5 inhibits cervical cancer progression by regulating AKT/p27, proposing the potential role of HOXA5 in the prevention and treatment of cervical cancer.

Wu Y, Zhou T, Tang Q, Xiao J
HOXA5 inhibits tumor growth of gastric cancer under the regulation of microRNA-196a.
Gene. 2019; 681:62-68 [PubMed] Related Publications
Homeobox A5 (HOXA5) is a member of the HOX protein family which were implicated in serval critical process and was cancer-specific dysregulated in human cancers. However, its expression and function in human gastric cancer (GC) was still largely unknown. In this study, we confirmed for the first time that HOXA5 mRNA and protein was down-regulated in GC tissues and cell lines. Clinical data showed that low HOXA5 was significantly associated poor prognostic features, including large tumor size and advanced TNM stage. For 5-year survival, HOXA5 served as a potential prognostic marker of GC patients. Notably, HOXA5 inhibited cell viability, colony formation, proliferation, cell cycle progression and promoted apoptosis in vitro and in vivo. Furthermore, we demonstrated that HOXA5 expression was regulated by miR-196a. In GC tissues, miR-196a has an inverse correlation with HOXA5 expression. Conclusively, our results demonstrated that HOXA5 functions as a tumor suppressor in regulating tumor growth of GC under regulation of miR-196a, supporting its potential utility as a therapeutic target for GC.

Zhao H, Yu H, Zheng J, et al.
Lowly-expressed lncRNA GAS5 facilitates progression of ovarian cancer through targeting miR-196-5p and thereby regulating HOXA5.
Gynecol Oncol. 2018; 151(2):345-355 [PubMed] Related Publications
PURPOSE: This investigation was aimed at extrapolating whether and how lncRNA GAS5, miR-196a-5p and HOXA5 altered progression of ovarian cancer (OA).
METHOD: Totally 195 pairs of OA tissues and adjacent normal tissues were collected. Also si-GAS5, pcDNA-GAS5, miR-196a-5p mimic, miR-196a-5p inhibitor and negative control (NC) were, respectively, transfected into OA cells. Besides, dual-luciferase reporter gene assay was performed to validate the targeted relationships between GAS5 and miR-196a-5p, as well as between miR-196a-5p and HOXA5. The impacts of GAS5, miR-196a-5p and HOXA5 on viability, proliferation and apoptosis of OA cells were appraised via conduction of colony formation assay, MTT assay and flow cytometry assay.
RESULT: Lower GAS5 expression and higher miR-196a-5p expression were associated with larger tumor size (≥5 cm) and more advanced FIGO stage (III-IV) of OA patients (P < 0.05). Transfection of si-GAS5, miR-196a-5p mimic or si-HOXA5 conferred OA cells with stronger viability, faster proliferation and smaller percentage of apoptosis (P < 0.05). After injecting mice models with si-GAS5, miR-196a-5p mimic or si-HOXA5, a larger tumor size was also observed within the rats (P < 0.05). GAS5 was indicated to directly target miR-196a-5p and modify its expression, and the targeted relationship also seemed to exist between miR-196a-5p and HOXA5 (P < 0.05). The HOXA5 was found to reverse the effects imposed by miR-196a-5p on viability, proliferation and apoptosis of OA cells (P < 0.05).
CONCLUSION: LncRNA GAS5 depressed OA development by targeting miR-196a-5p and thereby down-regulating HOXA5 expression, providing substance for developing lncRNA-based strategies to treat OA.

Kim KT, Lee CH, Chung CK, Kim JH
Is NF2 a Key Player of the Differentially Expressed Gene Between Spinal Cord Ependymoma and Intracranial Ependymoma?
World Neurosurg. 2018; 118:e906-e917 [PubMed] Related Publications
BACKGROUND: Although intracranial and spinal ependymomas are histopathologically similar, the molecular landscape is heterogeneous. An urgent need exists to identify differences in the genomic profiles to tailor treatment strategies. In the present study, we delineated differential gene expression patterns between intracranial and spinal ependymomas.
METHODS: We searched the Gene Expression Omnibus database using the term "ependymoma" and analyzed the raw gene expression profiles of 292 ependymomas (31 spinal and 261 intracranial). The gene expression data were analyzed to find differentially expressed genes (DEGs) between 2 regions. The fold change (FC) and false discovery rate (FDR) were used to assess DEGs after gene integration (|log
RESULTS: A total of 201 genes (105 upregulated and 96 downregulated) were significant DEGs in the data sets. The underexpression of NF2 in spinal ependymomas was statistically significant (FDR P = 7.91 × 10
CONCLUSIONS: The most substantial magnitude of DEGs in ependymoma might be HOX genes. However, whether the differential expression of these genes is the cause or consequence of the disease remains to be elucidated in a larger prospective study.

Peng X, Zha L, Chen A, Wang Z
HOXA5 is a tumor suppressor gene that is decreased in gastric cancer.
Oncol Rep. 2018; 40(3):1317-1329 [PubMed] Free Access to Full Article Related Publications
The abnormal expression of homeobox A5 (HOXA5) has been observed in breast and colon cancer; however, the clinical significance of HOXA5 in gastric cancer (GC) is not yet clear. In this study, we found that HOXA5 expression was decreased in GC tissues at the mRNA and protein level compared with paracancerous tissues using reverse transcription‑quantitative PCR (RT‑qPCR) and western blot analysis, respectively. Immunohistochemistry and Kaplan‑Meier survival analysis confirmed that the underexpression of HOXA5 was associated with GC progression and indicated a poor prognosis of patients with GC. Given that proliferation‑related genes may be potential target genes of HOXA5, we performed a series of experiments in vitro to examine the effects of HOXA5 on the proliferation of GC cells. A CCK‑8 assay, colony formation assay and flow cytometry revealed that HOXA5 inhibited the abnormal proliferation of GC cells, and this finding was further supported by a 5‑ethynyl‑2'‑deoxyuridine (EdU) assay. Further mechanistic investigation clarified that HOXA5 promoted the protein expression of p21 and inhibited the protein expression of c‑Myc and Ki67. Additionally, the use of nude mouse models also verified that HOXA5 suppressed the proliferation of GC cells in vivo. Collectively, the findings of this study demonstrate that HOXA5 acts as a tumor suppressor gene during the development and progresion of GC, possibly functioning by inhibiting the abnormal proliferation of cancer cells.

Cimino PJ, Kim Y, Wu HJ, et al.
Genes Dev. 2018; 32(7-8):512-523 [PubMed] Free Access to Full Article Related Publications
Glioblastoma is the most frequently occurring and invariably fatal primary brain tumor in adults. The vast majority of glioblastomas is characterized by chromosomal copy number alterations, including gain of whole chromosome 7 and loss of whole chromosome 10. Gain of whole chromosome 7 is an early event in gliomagenesis that occurs in proneural-like precursor cells, which give rise to all isocitrate dehydrogenase (IDH) wild-type glioblastoma transcriptional subtypes.

Gao XY, Qiao YL, Zhang Y, et al.
Knockdown of MPP8 suppresses cell proliferation via regulation of HOXA5 in non-small cell lung cancer cells.
Cell Mol Biol (Noisy-le-grand). 2018; 64(1):27-31 [PubMed] Related Publications
M-phase phosphoprotein 8 (MPP8) is reported to be closely implicated in cancer initiation and progression. In addition, the homeobox gene HOXA5 has been shown to play critical roles in hematopoiesis, embryogenesis, and tumorigenesis. Nevertheless, the functional relevance of MPP8 and it's relation with HOXA5 in non-small cell lung cancer (NSCLC) is unknown. Therefore, the present study aimed to detect the expression profile of MPP8 in NSCLC and further explore it's biological roles in lung cancer cells. Cell proliferation was measured by CCK-8 assay and EdU incorporation assay. Real-time PCR was applied to detect the mRNA expression of MPP8 and HOXA5. The protein levels of MPP8 and HOXA5 were evaluated by western blot. Our study found that the expression of MPP8 was significantly increased in the NSCLC tissue compared with the adjacent non-tumorous tissue. Compared with the human lung fibroblasts, the elevated gene expression of MPP8 was also detected in the human NSCLC cell lines including NCI-H23 and NCI-H1299. In addition, knockdown of MPP8 led to an obvious reduction in cell viability and DNA synthesis in NCI-H23 and NCI-H1299 cells. Furthermore, down-regulation of MPP8 resulted in elevated expression of HOXA5 in NSCLC cells both at the mRNA and protein levels. Moreover, depletion of HOXA5 abolished the anti-tumor function of MPP8 knockdown in NSCLC cells. The present study demonstrated that MPP8 was associated with NSCLC cell proliferation through regulation of HOXA5, suggesting that MPP8 may act as a novel therapeutic target for treatment of NSCLC.

Burillo-Sanz S, Morales-Camacho RM, Caballero-Velázquez T, et al.
MLL-rearranged acute myeloid leukemia: Influence of the genetic partner in allo-HSCT response and prognostic factor of MLL 3' region mRNA expression.
Eur J Haematol. 2018; 100(5):436-443 [PubMed] Related Publications
OBJECTIVE: MLL gene is involved in more than 80 known genetic fusions in acute leukemia. To study the relevance of MLL partner gene and selected gene's expression, in this work, we have studied a cohort of 20 MLL-rearranged acute myeloid leukemia (AML).
METHODS: Twenty MLL-rearranged AML patients along with a control cohort of 138 AML patients are included in this work. By RT-PCR and sequencing, MLL genetic fusion was characterized, and relative gene expression quantification was carried out for EVI1, MEIS1, MLL-3', RUNX1, SETBP1, HOXA5, and FLT3 genes. Risk stratification and association of MLL genetic partner and gene expression to overall survival, in the context of received therapy, were performed.
RESULTS: MLLr cohort showed to have an OS more similar to intermediate-risk AML. Type of MLL genetic partner showed to be relevant in allo-HSCT response; having MLLT1 and MLLT3, a better benefit from it. Expression of MLL-3' region, EVI1 and FLT3, showed association with OS in patients undergoing allo-HSCT.
CONCLUSION: We show that the MLL genetic partner could have implications in allo-HSCT response, and we propose three genes whose expression could be useful for the prognosis of this leukemia in patients undergoing allo-HSCT: 3' region of MLL, EVI1, and FLT3.

Wang YF, Liu F, Sherwin S, et al.
Cooperativity of HOXA5 and STAT3 Is Critical for HDAC8 Inhibition-Mediated Transcriptional Activation of PD-L1 in Human Melanoma Cells.
J Invest Dermatol. 2018; 138(4):922-932 [PubMed] Related Publications
Although the expression of programmed death-ligand 1 (PD-L1) is an important mechanism by which cancer cells evade the immune system, PD-L1 expression in cancer cells is commonly associated with patients' responses to treatment with anti-programmed death 1/PD-L1 antibodies. However, how PD-L1 expression is regulated in melanoma cells remains to be fully elucidated. Here we report that the class I histone deacetylase (HDAC) HDAC8 controls transcriptional activation of PD-L1 by a transcription complex consisting of transcription factors homeobox A5 and signal transducer and activator of transcription 3. Inhibition of HDAC8 upregulated PD-L1 in melanoma cells. This was due to an increase in the activity of a fragment of the PD-L1 gene promoter that is enriched with binding sites for both homeobox A5 and signal transducer and activator of transcription 3. Indeed, knockdown of homeobox A5 or signal transducer and activator of transcription 3 abolished upregulation of PD-L1 by HDAC8 inhibition. Moreover, homeobox A5 and signal transducer and activator of transcription 3 were physically associated and appeared interdependent in activating PD-L1 transcription. Functional studies showed that HDAC8-mediated regulation of PD-L1 expression participated in modulating anti-melanoma T-cell responses. Collectively, these results identify HDAC8 as an important epigenetic regulator of PD-L1 expression, with implications for better understanding of the interaction between melanoma cells and the immune system.

Reikvam H, Hovland R, Forthun RB, et al.
Disease-stabilizing treatment based on all-trans retinoic acid and valproic acid in acute myeloid leukemia - identification of responders by gene expression profiling of pretreatment leukemic cells.
BMC Cancer. 2017; 17(1):630 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Acute myeloid leukemia (AML) is an aggressive malignancy only cured by intensive therapy. However, many elderly and unfit patients cannot receive such treatment due to an unacceptable risk of treatment-related morbidity and mortality. Disease-stabilizing therapy is then the only possible strategy, one alternative being treatment based on all-trans retinoic acid (ATRA) combined with the histone deacetylase inhibitor valproic acid and possibly low-toxicity conventional chemotherapy.
METHODS: Primary AML cells were derived from 43 patients included in two clinical studies of treatment based on ATRA, valproic acid and theophyllamine; low toxicity chemotherapy (low-dose cytarabine, hydroxyurea, 6-mercaptopurin) was also allowed. Pretreatment leukemic cells were analyzed by mutation profiling of 54 genes frequently mutated in myeloid malignancies and by global gene expression profiling before and during in vivo treatment.
RESULTS: Patients were classified as responders and non-responders to the treatment, however response to treatment showed no significant associations with karyotype or mutational profiles. Significance analysis of microarray (SAM) showed that responders and non-responders significantly differed with regard to the expression of 179 different genes. The differentially expressed genes encoding proteins with a known function were further classified based on the PANTHER (protein annotation through evolutionary relationship) classification system. The identified genes encoded proteins that are involved in several important biological functions, but a main subset of the genes were important for transcriptional regulation. These pretherapy differences in gene expression were largely maintained during treatment. Our analyses of primary AML cells during in vivo treatment suggest that ATRA modulates HOX activity (i.e. decreased expression of HOXA3, HOXA4 and HOXA5 and their regulator PBX3), but altered function of DNA methyl transferase 3A (DNMT3A) and G-protein coupled receptor signaling may also contribute to the effect of the overall treatment.
CONCLUSIONS: Responders and non-responders to AML stabilizing treatment based on ATRA and valproic acid differ in the pretreatment transcriptional regulation of their leukemic cells, and these differences may be important for the clinical effect of this treatment.
TRIAL REGISTRATIONS: ClinicalTrials.gov no. NCT00175812 ; EudraCT no. 2004-001663-22, registered September 9, 2005 and ClinicalTrials.gov no. NCT00995332 ; EudraCT no. 2007-2007-001995-36, registered October 14, 2009.

Zhao Y, Min L, Xu C, et al.
Construction of disease-specific transcriptional regulatory networks identifies co-activation of four gene in esophageal squamous cell carcinoma.
Oncol Rep. 2017; 38(1):411-417 [PubMed] Related Publications
Even though various molecules may serve as biomarkers, little is known concerning the mechanisms underlying the carcinogenesis of ESCC, particularly the transcriptional regulatory network. Thus, in the present study, paired ESCC and non-cancerous (NC) tissues were assayed by Affymetrix microarray assays. Passing Attributes between Networks for Data Assimilation (PANDA) was used to construct networks between transcription factors (TFs) and their targets. AnaPANDA program was applied to compare the regulatory networks. A hypergeometric distribution model-based target profile similarity analysis was utilized to find co-activation effects using both TF-target networks and differential expression data. There were 1,116 genes upregulated and 1,301 genes downregulated in ESCC compared with NC tissues. In TF-target networks, 16,970 ESCC-specific edges and 9,307 NC-specific edges were identified. Edge enrichment analysis by AnaPANDA indicated 17 transcription factors (NFE2L2, ELK4, PAX6, TLX1, ESR1, ZNF143, TP53, REL, ELF5, STAT1, TBP, NHLH1, FOXL1, SOX9, STAT3, ELK1, and HOXA5) suppressed in ESCC and 5 (SPIB, BRCA1, MZF1, MAFG and NFE2L1) activated in ESCC. For SPIB, MZF1, MAFG and NFE2L1, a strong and significant co-activation effect among them was detected in ESCC. In conclusion, the construction of transcriptional regulatory networks found SPIB, MZF1, MAFG and NFE2L1 co-activated in ESCC, which provides distinctive insight into the carcinogenesis mechanism of ESCC.

Ma C, Wu G, Zhu Q, et al.
Long intergenic noncoding RNA 00673 promotes non-small-cell lung cancer metastasis by binding with EZH2 and causing epigenetic silencing of HOXA5.
Oncotarget. 2017; 8(20):32696-32705 [PubMed] Free Access to Full Article Related Publications
Metastasis of cancer cells is a key impediment to favorable outcomes of cancer treatment. Functional roles of long noncoding RNAs in several biological processes, including metastasis, have recently been discovered. In our previous work, we reported a positive correlation of increased expression of linc00673 in NSCLC tissues with tumor size, lymph node metastasis, TNM stage, and increased proliferation of NSCLC cells, both, in vitro and in vivo. In this study, we demonstrate that ectopic expression of linc00673 promotes migration and invasion of NSCLC cells. Furthermore, our results indicate that linc00673 could silence HOXA5 expression by recruiting epigenetic repressor, EZH2, at its promoter regions. HOXA5 was identified as a tumor suppressor gene, which inhibited NSCLC cell metastasis by regulating cytoskeletal remodeling. To summarize, we for the first time identified the role of lin00673 in promoting invasion and migration of NSCLC cells. Insights from this study may help to identify novel therapeutic targets for NSCLC.

Zhu Q, Lv T, Wu Y, et al.
Long non-coding RNA 00312 regulated by HOXA5 inhibits tumour proliferation and promotes apoptosis in Non-small cell lung cancer.
J Cell Mol Med. 2017; 21(9):2184-2198 [PubMed] Free Access to Full Article Related Publications
Non-small cell lung cancer (NSCLC) is the most prevalent type of lung cancer. The abnormal expression of many long non-coding RNAs (lncRNAs) has been reported involved in the progression of various tumours, which can be used as diagnostic indicators or antitumour targets. Here, we found that the long non-coding RNA 00312 was down-regulated in paired NSCLC tissues and correlated with poor clinical outcome; decreased linc00312 expression in NSCLC was associated with larger and later stage tumours. Functional experiments showed that linc00312 could inhibit cell proliferation and promote apoptosis in vitro and in vivo. Furthermore, we found that HOXA5 could bind in the promoter of linc00312 and up-regulated the expression of it. Moreover, linc00312 was down-regulated in the plasma of NSCLC patients compared with that of healthy volunteers or other pulmonary diseases patients. Taken together, our findings indicated that linc00312 could be a novel diagnosis biomarker and a promising therapeutic target for NSCLC.

Yan Z, Liu Y, Wei Y, et al.
The functional consequences and prognostic value of dosage sensitivity in ovarian cancer.
Mol Biosyst. 2017; 13(2):380-391 [PubMed] Related Publications
Copy number alteration (CNA) represents an important class of genetic variations that may contribute to tumorigenesis, tumor growth and metastatic spread. CNA can directly affect the expression of genes within the CNA regions; however, genes within the CNA regions exhibit heterogeneity in gene dosage sensitivity. In this study, a computational framework was built to identify 1170 dosage-sensitive genes (DSGs) and 1215 dosage-resistant genes (DRGs) that were related to ovarian serous cystadenocarcinoma (OV) through the association between CNA and gene expression. To analyze the different functions of the genes within the two groups, the functional annotation results indicated that DRGs were involved in cancer-related processes like immune response, cell death and apoptosis, while DSGs were enriched in essential processes like the cell cycle and the DNA metabolic process. Meanwhile, two three-dimensional regulatory networks for differentially expressed miRNAs, differentially expressed transcription factors (TFs) and DSGs or DRGs were constructed based on feed-forward loops. We identified key regulators (such as miR-16-5p, miR-98-5p, MYB and HOXA5) and cancer prognosis-related network motifs (such as miR-98-5p-HOXA5-TP53 and miR-16-5p-MYB-IGF1R) after the analysis of network topological features. Our results lead us to speculate that these genes and associated regulators may be potential mechanistic biomarkers for tumorigenesis and progression of cancer. Research on the network characteristics and the role of feed-forward loops in OV tumorigenesis and development could lead to feasible suggestions for the prevention and early diagnosis of OV, which will shed light on understanding the functional mechanism of CNA in cancer.

Li B, McCrudden CM, Yuen HF, et al.
CD133 in brain tumor: the prognostic factor.
Oncotarget. 2017; 8(7):11144-11159 [PubMed] Free Access to Full Article Related Publications
CD133 has been shown to be an important stem cell factor that promotes glioma progression. However, the mechanism for CD133-mediated glioma progression has yet to be fully elucidated. In this study, we found that CD133 mRNA expression was a prognostic marker in three independent glioma patient cohorts, corroborating a putative role for CD133 in glioma progression. Importantly, we found that CD133 expression in glioma was highly correlated with the expression of HOX gene stem cell factors (HOXA5, HOXA7, HOXA10, HOXC4 and HOXC6). The expression of these HOX genes individually was significantly associated with survival. Interestingly, the prognostic significance of CD133 was dependent on the expression level of HOX genes, and vice versa. CD133 (p = 0.021) and HOXA7 (p = 0.001) were independent prognostic markers when the three glioma patient cohorts were combined (n = 231). Our results suggest that HOX genes may play a more important role in progression of glioma when CD133 expression is low. Furthermore, we showed that low-level expression of LIM2 in CD133-high glioma was associated with poorer survival, suggesting that LIM2 could be a therapeutic target for glioma expressing a high level of CD133. Connectivity mapping identified vinblastine and vincristine as agents that could reverse the CD133/HOX genes/LIM2-signature, and we confirmed this by in vitro analysis in glioma cell lines, demonstrating that CD133 and HOX genes were co-expressed and could be downregulated by vincristine. In conclusion, our data show that CD133 and HOX genes are important prognostic markers in glioma and shed light on possible treatment strategies for glioma expressing a high level of CD133.

Zhang H, Zhao JH, Suo ZM
Knockdown of HOXA5 inhibits the tumorigenesis in esophageal squamous cell cancer.
Biomed Pharmacother. 2017; 86:149-154 [PubMed] Related Publications
Homeobox A5 (HOXA5) is a member of the homeobox (HOX) family and was upregulated in many types of tumors. However, its expression and role in esophageal squamous cell carcinoma (ESCC) remain unclear. In this study, the aim of this study was to investigate the expression and function of HOXA5 in ESCC. Our results showed that HOXA5 was highly expressed in ESCC cell lines. The in vitro experiments demonstrated that knockdown of HOXA5 significantly inhibited the proliferation, migration and invasion of ESCC cells. Furthermore, the in vivo experiments showed that knockdown of HOXA5 significantly inhibited the tumor growth of ESCC in mice xenograft model. Finally, sh-HOXA5 inhibited the expression of β-catenin, cyclin D1 and c-Myc in ESCC cells. Taken together, these data revealed that knockdown of HOXA5 suppressed the proliferation and metastasis partly by interfering with Wnt/β-catenin signaling pathway in ESCC cells. Therefore, these findings suggest that HOXA5 may be a potential therapeutic target for the treatment of ESCC.

Zang H, Li N, Pan Y, Hao J
Identification of upstream transcription factors (TFs) for expression signature genes in breast cancer.
Gynecol Endocrinol. 2017; 33(3):193-198 [PubMed] Related Publications
Breast cancer is a common malignancy among women with a rising incidence. Our intention was to detect transcription factors (TFs) for deeper understanding of the underlying mechanisms of breast cancer. Integrated analysis of gene expression datasets of breast cancer was performed. Then, functional annotation of differentially expressed genes (DEGs) was conducted, including Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Furthermore, TFs were identified and a global transcriptional regulatory network was constructed. Seven publically available GEO datasets were obtained, and a set of 1196 DEGs were identified (460 up-regulated and 736 down-regulated). Functional annotation results showed that cell cycle was the most significantly enriched pathway, which was consistent with the fact that cell cycle is closely related to various tumors. Fifty-three differentially expressed TFs were identified, and the regulatory networks consisted of 817 TF-target interactions between 46 TFs and 602 DEGs in the context of breast cancer. Top 10 TFs covering the most downstream DEGs were SOX10, NFATC2, ZNF354C, ARID3A, BRCA1, FOXO3, GATA3, ZEB1, HOXA5 and EGR1. The transcriptional regulatory networks could enable a better understanding of regulatory mechanisms of breast cancer pathology and provide an opportunity for the development of potential therapy.

Boi M, Todaro M, Vurchio V, et al.
Therapeutic efficacy of the bromodomain inhibitor OTX015/MK-8628 in ALK-positive anaplastic large cell lymphoma: an alternative modality to overcome resistant phenotypes.
Oncotarget. 2016; 7(48):79637-79653 [PubMed] Free Access to Full Article Related Publications
Anaplastic large cell lymphomas (ALCL) represent a peripheral T-cell lymphoma subgroup, stratified based on the presence or absence of anaplastic lymphoma kinase (ALK) chimeras. Although ALK-positive ALCLs have a more favorable outcome than ALK-negative ALCL, refractory and/or relapsed forms are common and novel treatments are needed. Here we investigated the therapeutic potential of a novel bromodomain inhibitor, OTX015/MK-8628 in ALK-positive ALCLs.The effects of OTX015 on a panel of ALK+ ALCL cell lines was evaluated in terms of proliferation, cell cycle and downstream signaling, including gene expression profiling analyses. Synergy was tested with combination targeted therapies.Bromodomain inhibition with OTX015 led primarily to ALCL cell cycle arrest in a dose-dependent manner, along with downregulation of MYC and its downstream regulated genes. MYC overexpression did not compensate this OTX015-mediated phenotype. Transcriptomic analysis of OTX015-treated ALCL cells identified a gene signature common to various hematologic malignancies treated with bromodomain inhibitors, notably large cell lymphoma. OTX015-modulated genes included transcription factors (E2F2, NFKBIZ, FOS, JUNB, ID1, HOXA5 and HOXC6), members of multiple signaling pathways (ITK, PRKCH, and MKNK2), and histones (clusters 1-3). Combination of OTX015 with the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib led to cell cycle arrest then cell death, and combination with suboptimal doses of the ALK inhibitor CEP28122 caused cell cycle arrest. When OTX015 was associated with GANT61, a selective GLI1/2 inhibitor, C1156Y-resistant ALK ALCL growth was impaired.These findings support OTX015 clinical trials in refractory ALCL in combination with inhibitors of interleukin-2-inducible kinase or SHH/GLI1.

Daugaard I, Dominguez D, Kjeldsen TE, et al.
Identification and validation of candidate epigenetic biomarkers in lung adenocarcinoma.
Sci Rep. 2016; 6:35807 [PubMed] Free Access to Full Article Related Publications
Lung cancer is the number one cause of cancer-related deaths worldwide. DNA methylation is an epigenetic mechanism that regulates gene expression, and disease-specific methylation changes can be targeted as biomarkers. We have compared the genome-wide methylation pattern in tumor and tumor-adjacent normal lung tissue from four lung adenocarcinoma (LAC) patients using DNA methylation microarrays and identified 74 differentially methylated regions (DMRs). Eighteen DMRs were selected for validation in a cohort comprising primary tumors from 52 LAC patients and tumor-adjacent normal lung tissue from 32 patients by methylation-sensitive high resolution melting (MS-HRM) analysis. Significant increases in methylation were confirmed for 15 DMRs associated with the genes and genomic regions: OSR1, SIM1, GHSR, OTX2, LOC648987, HIST1H3E, HIST1H3G/HIST1H2BI, HIST1H2AJ/HIST1H2BM, HOXD10, HOXD3, HOXB3/HOXB4, HOXA3, HOXA5, Chr1(q21.1).A, and Chr6(p22.1). In particular the OSR1, SIM1 and HOXB3/HOXB4 regions demonstrated high potential as biomarkers in LAC. For OSR1, hypermethylation was detected in 47/48 LAC cases compared to 1/31 tumor-adjacent normal lung samples. Similarly, 45/49 and 36/48 LAC cases compared to 3/31 and 0/31 tumor-adjacent normal lung samples showed hypermethylation of the SIM1 and HOXB3/HOXB4 regions, respectively. In conclusion, this study has identified and validated 15 DMRs that can be targeted as biomarkers in LAC.

Teo WW, Merino VF, Cho S, et al.
HOXA5 determines cell fate transition and impedes tumor initiation and progression in breast cancer through regulation of E-cadherin and CD24.
Oncogene. 2016; 35(42):5539-5551 [PubMed] Free Access to Full Article Related Publications
Loss of HOXA5 expression occurs frequently in breast cancer and correlates with higher pathological grade and poorer disease outcome. However, how HOX proteins drive differentiation in mammalian cells is poorly understood. In this paper, we investigated cellular and molecular consequences of loss of HOXA5 in breast cancer, and the role played by retinoic acid in HOXA5 function. Analysis of global gene expression data from HOXA5-depleted MCF10A breast epithelial cells, followed by validation, pointed to a role for HOXA5 in maintaining several molecular traits typical of the epithelial lineage such as cell-cell adhesion, tight junctions and markers of differentiation. Depleting HOXA5 in immortalized MCF10A or transformed MCF10A-Kras cells reduced their CD24

Cipollini M, Landi S, Gemignani F
Bonafide Targets of Deregulated microRNAs in Non-Small Cell Lung Cancer as Tool to Identify Novel Therapeutic Targets: A Review.
Curr Pharm Des. 2017; 23(1):55-72 [PubMed] Related Publications
BACKGROUND: Non-small-cell lung cancer (NSCLC) is an aggressive neoplasm with a poor survival and novel therapies are urgently needed. The study of deregulated micro- RNAs (dereg-miRs) could constitute a strategy helping to detect specific genes playing a relevant role in the disease. Thus, the oncoproteins encoded by these genes could be exploited as novel therapeutic targets to be inhibited by small molecules, aptamers, or monoclonal antibodies.
METHODS: The present review is focused on candidate genes having convincing biological evidences to be both bona fide targets for dereg-miRs and playing a role in NSCLC progression. These genes were evaluated according to the molecular pathway they belong. Moreover, in the attempt to provide an even broader list of candidate therapeutic targets for NSCLC, the full list of genes was analyzed using the online tool Interactome DB.
RESULTS: Among the identified targets, some of them belong to p53 or MAP kinase signaling pathways, and others include caspases, MCL1, and BCL2L2 (playing a role in apoptosis), ZEB1, ZEB2, and USP25 (epithelial-to-mesenchymal transition), EZH2, SOX9, and HOXA5 (differentiation), Paxillin, LIMK1 and MTDH (cytoskeleton remodeling), and HDGF (angiogenesis). In addition, other targets, such as TIMP-2, PIM-1, and components of the IGF-signaling pathways were suggested following the interactome analysis.
CONCLUSION: Studies on dereg-miRs helped to identify a set of genes whose encoded proteins could constitute candidates for future therapeutic approaches.

Saijo H, Hirohashi Y, Torigoe T, et al.
Plasticity of lung cancer stem-like cells is regulated by the transcription factor HOXA5 that is induced by oxidative stress.
Oncotarget. 2016; 7(31):50043-50056 [PubMed] Free Access to Full Article Related Publications
Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are reasonable targets for cancer therapy. However, recent studies have revealed that some non-CSCs/CICs have plastic ability and can dedifferentiate into CSCs/CICs. Therefore, an understanding of the molecular mechanisms that control the plasticity is essential to achieve CSC/CIC-targeting therapy. In this study, we analyzed the plasticity of lung cancer cells and found that lung non-CSCs/CICs can dedifferentiate into CSCs/CICs in accordance with the expression of stem cell transcription factor SOX2. SOX2 expression was induced by the transcription factor HOXA5. Oxidative stress repressed the expression of HDAC8 and then induced histone 3 acetylation and increased the expression of HOXA5 and SOX2. These findings indicate that lung cancer cells have plasticity under a condition of oxidative stress and that HOAX5 has a critical role in dedifferentiation.

Zhao MY, Yu Y, Xie M, et al.
Digital gene expression profiling analysis of childhood acute lymphoblastic leukemia.
Mol Med Rep. 2016; 13(5):4321-8 [PubMed] Related Publications
Acute lymphoblastic leukemia (ALL) is the most commonly diagnosed malignancy in children. It is a heterogeneous disease, and is determined by multiple gene alterations and chromosomal rearrangements. To improve current understanding of the underlying molecular mechanisms of ALL, the present study profiled genome‑wide digital gene expression (DGE) in a population of children with ALL in China. Using second‑generation sequencing technology, the profiling revealed that 2,825 genes were upregulated and 1,952 were downregulated in the ALL group. Based on the DGE profiling data, the present study further investigated seven genes (WT1, RPS26, MSX1, CD70, HOXC4, HOXA5 and HOXC6) using reverse transcription‑quantitative polymerase chain reaction analysis. Gene Ontology analysis suggested that the differentially expressed genes were predominantly involved in immune cell differentiation, metabolic processes and programmed cell death. The results of the present study provided novel insights into the gene expression patterns in children with ALL.

Liu WJ, Zhang T, Guo QL, et al.
Effect of ATRA on the expression of HOXA5 gene in K562 cells and its relationship with cell cycle and apoptosis.
Mol Med Rep. 2016; 13(5):4221-8 [PubMed] Free Access to Full Article Related Publications
Leukemia is the most common malignant disease in children with high incidence and mortality rates, and a poor treatment effect. The aim of the present study was to examine the changes in the expression of homeobox (Hox) A5 gene and its relationship with cell cycle and apoptosis through the intervention of human K562 myeloid leukemia cell line by all-trans retinoic acid (ATRA), to analyze the role of HOXA5 in the pathogenesis and development process of myeloid leukemia. The optimal concentration of ATRA to be used with K562 cells was determined using a cell counting kit‑8 (CCK‑8). After 24, 72 and 48 h following treatment of K562 cells with 10 µmol/l ATRA, cell cycle events and apoptosis were measured using flow cytometry. HOXA5 mRNA and protein expression in K562 cells was assessed by RT‑PCR and western blot analysis, and the relationship between HOXA5 expression and cell cycle and apoptosis was analyzed. The HOXA5 mRNA and protein expression levels were increased following treatment with ATRA in K562 cells. Apoptosis was increased significantly. The cell cycle was inhibited in G0/G1 phase. Cell proliferation was also inhibited. HOXA5 mRNA and protein expression rates positively correlated with cell apoptosis and the increased percentage and cell cycle of the G0/G1 phase. However, HOXA5 negatively correlated with the reduced percentage of S stage. In conclusion, the expression of HOXA5 in cells was increased following treatment with ATRA in K562 cells, in a time-dependent manner. Additionally, ATRA may inhibit the proliferation of K562 cells and promote apoptosis by upregulating the HOXA5 mRNA and protein expression.

Huang HP, Liu WJ, Guo QL, Bai YQ
Effect of silencing HOXA5 gene expression using RNA interference on cell cycle and apoptosis in Jurkat cells.
Int J Mol Med. 2016; 37(3):669-78 [PubMed] Free Access to Full Article Related Publications
Acute lymphocytic leukemia (ALL) is a common malignant tumor with a high morbidity rate among children, accounting for approximately 80% of leukemia cases. Although there have been improvements in the treatment of patients frequent relapse lead to a poor prognosis. The aim of the present study was to determine whether HOXA5 may be used as a target for gene therapy in leukemia in order to provide a new treatment. Mononuclear cells were extracted from the bone marrow according to the clinical research aims. After testing for ALL in the acute stage, the relative mRNA and protein expression of HOXA5 was detected in the ALL remission groups (n=25 cases per group) and the control group [n=20 cases, immune thrombocytopenia (ITP)]. Gene silencing by RNA interference (RNAi) was used to investigate the effect of silencing HOXA5 after small interfering RNA (siRNA) transfection to Jurkat cells. The HOXA5-specific siRNA was transfected to Jurkat cells using lipofectamine. The experiment was divided into the experimental group (liposomal transfection of HOXA5 targeting siRNA), the negative control group (liposomal transfection of cells with negative control siRNA) and the control group (plus an equal amount of cells and culture media only). Western blotting and quantitative fluorescent polymerase chain reaction (QF‑PCR) were used to detect the relative HOXA5 mRNA expression and protein distribution in each cell group. Cell distribution in the cell cycle and the rate of cells undergoing apoptosis were determined using flow cytometry. The expression of HOXA5 at the mRNA and protein levels in the acute phase of ALL was significantly higher than that in ALL in the remission and control groups. In cells transfected with HOXA5-specific siRNA, the expression of HOXA5 at the mRNA and protein levels decreased significantly (P<0.05). The distribution of cells in the cell cycle was also altered. Specifically, more cells were present in the G0/G1 phase compared to the S phase (P<0.05). In addition, the apoptotic rate was significantly higher in cells transfected with HOXA5‑specific siRNA (P<0.05). In conclusion, high expression levels of HOXA5 mRNA and protein in children with ALL indicate that HOXA5 is closely associated with childhood ALL. In addition, HOXA5-specific siRNA effectively silences HOXA5 gene expression and induces apoptosis and cell-cycle arrest in Jurkat cells, thus inhibiting cell proliferation.

Ordóñez-Morán P, Dafflon C, Imajo M, et al.
HOXA5 Counteracts Stem Cell Traits by Inhibiting Wnt Signaling in Colorectal Cancer.
Cancer Cell. 2015; 28(6):815-829 [PubMed] Related Publications
Hierarchical organization of tissues relies on stem cells, which either self-renew or produce committed progenitors predestined for lineage differentiation. Here we identify HOXA5 as an important repressor of intestinal stem cell fate in vivo and identify a reciprocal feedback between HOXA5 and Wnt signaling. HOXA5 is suppressed by the Wnt pathway to maintain stemness and becomes active only outside the intestinal crypt where it inhibits Wnt signaling to enforce differentiation. In colon cancer, HOXA5 is downregulated, and its re-expression induces loss of the cancer stem cell phenotype, preventing tumor progression and metastasis. Tumor regression by HOXA5 induction can be triggered by retinoids, which represent tangible means to treat colon cancer by eliminating cancer stem cells.

Mustafa M, Lee JY, Kim MH
CTCF negatively regulates HOXA10 expression in breast cancer cells.
Biochem Biophys Res Commun. 2015; 467(4):828-34 [PubMed] Related Publications
HOX genes not only play important roles in defining body patterning during embryonic development, but also control numerous cellular events in adult cells. Deregulated HOX gene expression in different cancers including breast cancer is now increasingly being reported. Given that human HOXA cluster is marked with several CTCF binding sites, we investigated whether the presence of CTCF is associated directly with expression of HOXA genes in breast cancer cells. Several HOX genes, such as HOXA4, HOXA5 and HOXA10, were deregulated by CTCF overexpression and knockdown in MCF-7 cells. Among these genes, HOXA10 is an emerging tumor suppressor for its role in activation of p53 and in countering tumorigenesis in breast cancer. Here we provided evidences that CTCF functions as a negative regulator of HOXA10 in breast cancer cells. The putative promoter region of HOXA10 lies between 5.3 and 6.1 kb upstream of its start codon and its promoter activity was negatively regulated by CTCF. Together with in-silico analysis and in vitro mutation assay we identified a 20 bp CTCF binding motif flanking with core promoter element of HOXA10. HOXA10 promoter region was kept inactivated by maintaining H3K27me3 inactivation marks in the presence of CTCF. Epigenetic silencing of HOXA10 by CTCF in breast cancer cells may contribute towards tumorigenesis by decreasing apoptosis and promoting metastasis.

Burillo-Sanz S, Morales-Camacho RM, Caballero-Velázquez T, et al.
NUP98-HOXA9 bearing therapy-related myeloid neoplasm involves myeloid-committed cell and induces HOXA5, EVI1, FLT3, and MEIS1 expression.
Int J Lab Hematol. 2016; 38(1):64-71 [PubMed] Related Publications
INTRODUCTION: Chromosomal rearrangements involving NUP98 gene have been associated with human leukemias such as de novo AML, therapy-related AML (t-AML), myelodysplastic syndrome (MDS), and chronic myeloid leukemia (CML). Genetic fusion NUP98-HOXA9, caused by t(7;11)(p15;p15), is a recurrent cytogenetic alteration in de novo acute myeloid leukemia (AML) usually found in young Asian patients and its description in therapy-related myeloid neoplasms (t-MN) is rare. Only one Asian case with molecular demonstration of the NUP98-HOXA9 fusion has been reported in therapy-related leukemia. NUP98-HOXA9 leukemogenic mechanism is derived from the transcription factor activity of the chimeric protein, which enhances the expression of genes related to cellular differentiation arrest and proliferation.
PATIENTS AND METHODS: We studied a Caucasian woman with a therapy-related acute myeloid leukemia after Ewing's sarcoma. Molecular demonstration of the genetic fusion NUP98-HOXA9 was performed by RT-PCR, and gene expression was analyzed by real-time PCR, including four AML patients with MLL rearrangements for comparative analysis. Cytologic and flow cytometric analysis was also carried out.
RESULTS: After cytologic and flow cytometric analysis diagnostics was therapy-related myeloid neoplasm (t-MN). The major component of blasts in the acute leukemia was with neutrophilic differentiation, but 13% erythroid lineage blasts were also found. Cytogenetic and FISH analysis revealed t(7;11)(p15;p15) and NUP98-HOXA9 fusion gene was demonstrated. Gene expression analysis showed upregulation of EVI1 and MEIS1 in the index patient, both of them previously related to a worst outcome.
CONCLUSION: In this work, we include a detailed molecular, clinical, cytological, and cytometric study of the second t-AML bearing NUP98-HOXA9 genetic fusion.

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