HOXA9 Transcriptionally Promotes Apoptosis and Represses Autophagy by Targeting NF-κB in Cutaneous Squamous Cell Carcinoma

HOXA9 versus HOXB9; particular focus on their controversial role in tumor pathogenesis

The Homeobox (HOX) gene family is essential to regulating cellular processes because it maintains the exact coordination required for tissue homeostasis, cellular differentiation, and embryonic development. The most distinctive feature of this class of genes is the presence of the highly conserved DNA region known as the homeobox, which is essential for controlling their regulatory activities. Important players in the intricate process of genetic regulation are the HOX genes. Many diseases, especially in the area of cancer, are linked to their aberrant functioning. Due to their distinctive functions in biomedical research-particularly in the complex process of tumor advancement-HOXA9 and HOXB9 have drawn particular attention. HOXA9 and HOXB9 are more significant than what is usually connected with HOX genes since they have roles in the intricate field of cancer and beyond embryonic processes. The framework for a focused study of the different effects of HOXA9 and HOXB9 in the context of tumor biology is established in this study.

Pan-cancer exploration of oncogenic and clinical impacts revealed that HOXA9 is a diagnostic indicator of tumorigenesis

Homeodomain transcription factor A9 (HOXA9) is a member of the HOX cluster family of transcription factors that are crucially involved in embryo implantation, morphogenesis, body axis development, and endothelial cell differentiation. Despite numerous reports on its aberrant expression in a few malignancies, the molecular and functional complexity of HOXA9 across cancers remains obscure. We aimed to analyze the dynamic role of HOXA9 across cancers by identifying, analyzing, and understanding its multiple modes of regulation and functional implications and identifying possible therapeutic avenues. We conducted a comprehensive analysis to determine the role of HOXA9 across cancers. This approach involved the integration of large-scale datasets from public repositories such as the Genomic Data Commons, specifically the Cancer Genome Atlas (GDC-TCGA), across 33 different cancer types. The multiple modes of HOXA9 regulation by genetic and epigenetic factors were determined using online tools, which comprised experimentally validated observations. Furthermore, downstream pathways were identified by predicting the targets of HOXA9 and by performing functional enrichment analysis. We also assessed the clinical significance of HOXA9 in terms of prognosis and stage stratification. This study evaluated the correlation between HOXA9 and tumor-infiltrating molecules and discussed its association with therapeutically approved antineoplastic drugs. HOXA9 was significantly upregulated in 9 tumors and downregulated in 2 cancers. The deregulation of HOXA9 is primarily attributed to epigenetic factors, including promoter DNA methylation and noncoding RNAs (ncRNAs). The HOXA9 transcription factor interacts with PBX/MEIS cofactors and regulates multiple genes involved in cancer-associated EMT, autophagy, the cell cycle, metabolic pathways, Wnt signaling, TGF-β signaling, the AMPK pathway, PI3K/AKT signaling, and NF-κB signaling, thereby establishing control over downstream mechanisms. Differential expression in various clinical stages across cancers was shown to have prognostic significance and to be correlated with tumor-infiltrating immune molecules. The assessment of the correlation of HOXA9 expression with approved antineoplastic drugs revealed that targeting HOXA9 could be the most reliable strategy for preventing cancer progression. HOXA9 is upregulated in the majority of malignancies and drives cancer progression by regulating multiple signaling mechanisms. Hence, HOXA9 could be a reliable diagnostic indicator and a potential therapeutic candidate for solid cancer types.

HOXA9 transcription factor is a double-edged sword: from development to cancer progression

The HOXA9 transcription factor serves as a molecular orchestrator in cancer stemness, epithelial-mesenchymal transition (EMT), metastasis, and generation of the tumor microenvironment in hematological and solid malignancies. However, the multiple modes of regulation, multifaceted functions, and context-dependent interactions responsible for the dual role of HOXA9 as an oncogene or tumor suppressor in cancer remain obscure. Hence, unravelling its molecular complexities, binding partners, and interacting signaling molecules enables us to comprehend HOXA9-mediated transcriptional programs and molecular crosstalk. However, it is imperative to understand its central role in fundamental biological processes such as embryogenesis, foetus implantation, hematopoiesis, endothelial cell proliferation, and tissue homeostasis before designing targeted therapies. Indeed, it presents an enormous challenge for clinicians to selectively target its oncogenic functions or restore tumor-suppressive role without altering normal cellular functions. In addition to its implications in cancer, the present review also focuses on the clinical applications of HOXA9 in recurrence and drug resistance, which may provide a broader understanding beyond oncology, open new avenues for clinicians for accurate diagnoses, and develop personalized treatment strategies. Furthermore, we have also discussed the existing therapeutic options and accompanying challenges in HOXA9-targeted therapies in different cancer types.

HOXA9 gene inhibits proliferation and differentiation and promotes apoptosis of bovine preadipocytes

BACKGROUND

Hox gene family is an important transcription factor that regulates cell process, and plays a role in the process of adipocytes differentiation and fat deposition. Previous transcriptome sequencing studies have indicated that the Homeobox A9 gene (HOXA9) is a candidate gene for regulating the process of bovine lipid metabolism, but the function and specific mechanism of action remain unclear. Therefore, this study aims to explore the role of HOXA9 in the proliferation, differentiation and apoptosis of bovine preadipocytes through gain-of-function and lose-of-function.

RESULT

It found HOXA9 highly expressed in bovine adipose tissue, and its expression level changed significantly during adipocytes differentiation process. It gave a hint that HOXA9 may be involved in the process of bovine lipid metabolism. The results of HOXA9 gain-of-function experiments indicated that HOXA9 appeared to act as a negative regulator not only in the differentiation but also in the proliferation of bovine preadipocytes, which is mainly reflected that overexpression of HOXA9 down-regulate the mRNA and protein expression level of PPARγ, CEBPα and FABP4 (P < 0.05). The mRNA expression level of CDK1, CDK2, PCNA, CCNA2, CCNB1, CCND1 and CCNE2, as well as the protein expression of CDK2 also significantly decreased. The decrease of lipid droplets content was the main characteristic of the phenotype (P < 0.01), which further supported the evidence that HOXA9 was a negative regulator of preadipocytes differentiation. The decrease of cell proliferation rate and EdU positive rate, as well as the limitation of transition of preadipocytes from G0/G1 phase to S phase also provided evidence for the inhibition of proliferation. Apart from this above, we noted an interesting phenomenon that overexpression of HOXA9 showed in a significant upregulation of both mRNA and protein level of apoptosis markers, accompanied by a significant increase in cell apoptosis rate. These data led us not to refute the fact that HOXA9 played an active regulatory role in apoptosis. HOXA9 loss-of-function experiments, however, yielded the opposite results. Considering that HOXA9 acts as a transcription factor, we predicted its target genes. Dual luciferase reporter assay system indicated that overexpression of HOXA9 inhibits activity of PCNA promoter.

CONCLUSION

Taken together, we demonstrated for the first time that HOXA9 played a role as a negative regulatory factor in the differentiation and proliferation of preadipocytes, but played a positive regulatory role in apoptosis, and it may play a regulatory role by targeting PCNA. This study provides basic data for further exploring the regulatory network of intramuscular fat deposition in bovine.

Targeting autophagy with natural products as a potential therapeutic approach for diabetic microangiopathy

As the quality of life improves, the incidence of diabetes mellitus and its microvascular complications (DMC) continues to increase, posing a threat to people's health and wellbeing. Given the limitations of existing treatment, there is an urgent need for novel approaches to prevent and treat DMC. Autophagy, a pivotal mechanism governing metabolic regulation in organisms, facilitates the removal of dysfunctional proteins and organelles, thereby sustaining cellular homeostasis and energy generation. Anomalous states in pancreatic β-cells, podocytes, Müller cells, cardiomyocytes, and Schwann cells in DMC are closely linked to autophagic dysregulation. Natural products have the property of being multi-targeted and can affect autophagy and hence DMC progression in terms of nutrient perception, oxidative stress, endoplasmic reticulum stress, inflammation, and apoptosis. This review consolidates recent advancements in understanding DMC pathogenesis via autophagy and proposes novel perspectives on treating DMC by either stimulating or inhibiting autophagy using natural products.

SIRT7 sustains tumor development and radioresistance by repressing endoplasmic reticulum stress-induced apoptosis in cutaneous melanoma

Cutaneous melanoma is one of the most malignant human tumors and possesses strong resistance to radiotherapy. However, the mechanisms contribute to such radioresistance of melanoma is unclear. In this study, SIRT7 is identified to be higher-expressed in melanoma and positively correlated with melanoma staging. Under ionizing radiation (IR)-treatment condition, loss of SIRT7 compromised the survivability of melanoma cells showed by decreased proliferation, colony formation, migration, but enhancing apoptosis. Transcriptomic sequencing analysis indicated the apoptosis induced after SIRT7 knockdown is tightly related with the induction of endoplasmic reticulum stress (ER stress) by IR treatment. Loss of SIRT7 enhanced EIF2α acetylation and activated its phosphorylation to induce the expression of ER stress proteins including DDIT3, XBP1 and GRP78, among which DDIT3 is responsible for apoptosis induction. SIRT7 depletion enriched ER stress-activated transcription factor ATF4 at the promoter region of DDIT3 gene to transactivate its expression and induces apoptotic cascade in both mock- and IR-treatment conditions. Consistently, SIRT7 is highly upregulated in radioresistant melanoma cell strain and still modulates the ER-stress responsive genes to maintain the homeostasis of melanoma. Collectively, SIRT7 negatively regulates ER stress-activated apoptosis to enhance the survivability of melanoma cells in both non-IR- and IR-treatment conditions. Our study highlights the role of SIRT7 in repressing ER stress and the following apoptosis to sustain tumor development and mediate radioresistance in melanoma, which may suggest a novel intervention target for melanoma therapy.

Role of HOXA9 in solid tumors: mechanistic insights and therapeutic potential

HOXA9 functioning as a transcription factor is one of the members of HOX gene family, which governs multiple cellular activities by facilitating cellular signal transduction. In addition to be a driver in AML which has been widely studied, the role of HOXA9 in solid tumor progression has also received increasing attention in recent years, where the aberrant expression of HOXA9 is closely associated with the prognosis of patient. This review details the signaling pathways, binding partners, post-transcriptional regulation of HOXA9, and possible inhibitors of HOXA9 in solid tumors, which provides a reference basis for further study on the role of HOXA9 in solid tumors.

Comprehensive analysis of a homeobox family gene signature in clear cell renal cell carcinoma with regard to prognosis and immune significance

The homeobox (HOX) family genes have been linked to multiple types of tumors, while their effect on malignant behaviors of clear cell renal cell carcinoma (ccRCC) and clinical significance remains largely unknown. Here, we comprehensively analyzed the expression profiles and prognostic value of HOX genes in ccRCC using datasets from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases. We developed a prognostic signature comprising eight HOX genes (HOXB1, HOXA7, HOXB5, HOXD8, HOXD9, HOXB9, HOXA9, and HOXA11) for overall survival prediction in ccRCC and it allowed patients to be subdivided into high- and low-risk groups. Kaplan-Meier survival analysis in all the internal and external cohorts revealed significant difference in clinical outcome of patients in different risk groups, indicating the satisfactory predictive power of the signature. Additionally, we constructed a prognostic nomogram by integrating signature-derived risk score and clinical factors such as gender, age, T and M status, which might be helpful for clinical decision-making and designing tailored management schedules. Immunological analysis revealed that the regulatory T cells (Tregs) infiltrated differently between the two subgroups in both TCGA and ICGC cohorts. ssGSEA method showed that the enrichment scores for mast cells were significantly lower in high-risk group compared with the low-risk group, which was consistent in both TCGA and ICGC cohorts. As for the related immune function, the enrichment scores of APC co-inhibition, para-inflammation, and type II IFN response were consistently lower in high-risk group in both cohorts. Of the eight HOX genes, the mRNA and protein levels of HOXD8 were downregulated in ccRCC than that in normal tissues, and decreased expression of HOXD8 was associated with increased tumor grade and stage, and lymph node metastasis. Survival analysis revealed that lower expression of HOXD8 predicted worse overall survival in ccRCC. In conclusion, our HOX gene-based signature was a favorable indicator to predict the prognosis of ccRCC cases and associated with immune cell infiltration. HOXD8 might be a tumor suppressor gene in ccRCC and a potential predictor of tumor progression.

Muscone suppresses myocardial ischemia damage by regulating PI3K/Akt signaling pathway

Muscone is the main active compound of Moschus. In this paper, the cardioprotective effect of Muscone on acute myocardial ischemia (AMI) rats and its potential mechanisms were investigated. AMI rat models were established to evaluate the protective effect and antioxidative function of Muscone on the hearts. Moreover, Western blot analysis was conducted to quantify the phosphorylated PI3K and AKT levels in PI3K/Akt pathway for further investigating the mechanism of Muscone. Results showed that Muscone could markedly lessen the infarct size and myocardial injury, improve cardiac function, inhibit cardiomyocyte apoptosis and down-regulate serum reactive oxygen species level as indicated by the decreased MDA, BNP and c-TnI activities and the increased SOD, GSH-px, CAT activities and the expression of Bax protein. In addition, it was revealed that Muscone notably promoted the phosphorylation of PI3K and AKT. These findings denote that Muscone exerts a protective effect in heart via inhibition of oxidative stress and apoptosis, offering new insights into the treatment of CHD and the clinical application of Muscone.

MiR-19b-3p promotes tumor progression of non-small cell lung cancer via downregulating HOXA9 and predicts poor prognosis in patients

MiR-19b-3p has been reported in several types of human cancer. Nevertheless, the expression profile and biological functions of miR-19b-3p remain unclear in non-small cell lung cancer (NSCLC). The expression level of miR-19b-3p was evaluated in NSCLC tissues and cell lines using qRT-PCR. Survival analysis was performed using Kaplan-Meier curves, while the prognostic significance of miR-19b-3p was analyzed using Cox regression analysis in 80 NSCLC patients. The effects of miR-19b-3p on cell proliferation and invasion capacities were analyzed using CCK-8, crystal violet, and transwell assays. Target genes of miR-19b-3p were assessed using luciferase reporter assay, qRT-PCR, Western blot and rescue experiments. MiR-19b-3p was found to be upregulated in human NSCLC tissues and cell lines. The expression of miR-19b-3p was observed to be closely associated with TNM stage and metastasis. High expression of miR-19b-3p was found to be capable of predicting poor clinical prognosis in NSCLC patients. Whilst overexpression of miR-19b-3p was demonstrated to promote the proliferation and invasion of NSCLC cells, knockdown of miR-19b-3p showed an opposite inhibitory effect. Bioinformatics analysis and luciferase reporter assays confirmed that HOXA9 is a direct target of miR-19b-3p. Functional assays demonstrated that NSCLC cell proliferation and invasion were promoted by miR-19b-3p via negative regulation of HOXA9. Finally, overexpression of HOXA9 was shown to partially reverse the tumor promoting effect of miR-19b-3p. This study indicates that miR-19b-3p is a crucial prognostic biomarker of NSCLC, and that targeting of the miR-19b-3p/HOXA9 axis may be a promising strategy in NSCLC therapy.

The correlation of fibrinogen-like protein-1 expression with the progression and prognosis of hepatocellular carcinoma

BACKGROUND

Fibrinogen-like-protein 1 (FGL1), a member of the fibrinogen-related protein (FREP) family, is a major ligand of the immune inhibitory receptor lymphocyte-activation gene 3 (LAG-3). While FGL1 is strongly implicated in the development and prognosis of a variety of diseases, its role in hepatocellular carcinoma (HCC) is still disputed. Therefore, the role of FGL1 expression in the progression and prognosis of HCC was investigated.

METHODS AND RESULTS

In the present study, bioinformatics analysis was first used to probe the expression profile of FGL1 in multiple malignant tumor tissues and paired normal tissues, and to explore the possible relationship between FGL1 and prognosis of HCC patients. Thereafter, the expression levels of FGL1 were determined and compared in human HCC cell lines, HCC tissues, peri-tumor tissues and normal liver tissues by western blot analysis. Furthermore, tissue microarrays were used to detect the expression of FGL1 through immunohistochemical staining and to verify whether the FGL1 expression level was associated with clinicopathological features and the prognosis of HCC patients. The results showed that FGL1 was downregulated significantly in most of the HCC cells lines and HCC tissues, corresponding to the results of the bioinformatics and western blot analyses. FGL1 expression level in HCC was found to be correlated to Edmondson grade and metastasis of the HCC. Additionally, high FGL1 expression was associated with better overall survival in HCC patients, suggesting that FGL1 could function as a tumor suppressor.

CONCLUSIONS

The expression level of FGL1 can be correlated with the progression and prognosis of HCC, suggesting its potential as a prognostic biomarker.

TOPK Affects Autophagy of Skin Squamous Cell Carcinoma by Regulating NF-KB Pathway through HDAC1

Objective

To explore the effect and potential mechanism of T-LAK cell-originated protein kinase (TOPK) on autophagy in cutaneous squamous cell carcinoma (cSCC).

Methods

Human cSCC cancer tissue and paracancerous tissue samples were collected clinically; immunohistochemistry was used to detect the expression of TOPK, nuclear factor κB p65 (NF-κB p65), phosphorylated nuclear factor κB inhibitor α (p-IκBα), Beclin-1, and microtubule-associated protein 1 light chain 3 (LC3) in cSCC tissue; and immunofluorescence was adopted to detect the coexpression of NF-κB p65, p-IκBα, and TOPK in cSCC tissue. After TOPK silencing or overexpression, SCL-1 and A431 cells were treated with PDTC and 3-MA, respectively. RT-qPCR and Western Blot were used to detect the mRNA and protein expressions of histone deacetylase 1 (HDAC1) in TOPK-silenced/overexpressing cells. Western Blot was performed to detect the protein expressions of NF-κB p65, p-p65, IκBα, p-IκBα, Beclin-1, and LC3 in each group. Transwell and scratch healing experiments were used to detect the ability of cells to invade and migrate. The formation of autophagosomes in each group was observed by TEM.

Results

Compared with adjacent tissues, TOPK, NF-κB p65, p-IκBα, Beclin-1, and LC3 were highly expressed in cSCC cancer tissues; TOPK and NF-κB p65 were coexpressed; and TOPK and p-IκBα were expressed in cSCC cancer tissues both increased. The mRNA and protein levels of TOPK in human cSCC cells were significantly higher than those in human normal skin HaCaT cells. After TOPK knockout, the expression of HDAC1, p-IκBα/IκBα, NF-κB p65, p-p65, Beclin-1, LC3II/I proteins, cell invasion, and migration abilities were significantly reduced, and fewer autophagosomes were observed. Treatment with PDTC and 3-MA significantly downregulated NF-κB pathway protein activity and autophagy level and reduced cell migration and invasion ability.

Conclusion

TOPK promotes the malignant progression of cSCC by upregulating HDAC1 to activate the NF-κB pathway and promote autophagy.

BRAF-activated WT1 contributes to cancer growth and regulates autophagy and apoptosis in papillary thyroid carcinoma

Background

Papillary thyroid carcinoma (PTC) is one of most prevalent malignant endocrine neoplasms, and it is associated with a high frequency of BRAF gene mutations, which lead to lymphatic metastasis and distant metastasis that promote tumor progression. The molecular mechanism of PTC and the role of BRAF mutation in PTC progression and development need to be further elucidated.

Methods

In this study, a comprehensive bioinformatics analysis was performed to identify the differentially expressed genes and signaling pathways in thyroid cancer patients carrying mutant BRAF. Then, we confirmed the prognostic role of WT1 in thyroid cancer patients. Immunohistochemistry was performed to measure the expression profile of WT1 in PTC tissue. Lentivirus shWT1 was transfected into BRAFV600E (mutant) PTC cells to stably inhibit WT1 expression. CCK-8, EdU, immunofluorescence, colony formation, cell migration, cell wound healing, apoptosis and autophagy assays were performed to assess the biological functions of WT1 in BRAFV600E PTC cells. RNA sequencing, immunohistochemistry and immunoblotting were performed to explore the molecular mechanism of WT1 in BRAFV600E PTC cells.

Results

The results confirmed that “epithelial cell proliferation”, “apoptosis” and “selective autophagy” were closely associated with this BRAF mutant in these thyroid cancer patients. Knocking down BRAF-activated WT1 effectively inhibited the proliferation and migration of BRAFV600E PTC cells. Silencing WT1 significantly inhibited autophagy and promoted the apoptosis of BRAFV600E PTC cells. Mechanistic investigations showed that silencing WT1 expression remarkably suppressed the AKT/mTOR and ERK/P65 signaling pathways in BRAFV600E PTC cells.

Conclusion

All these results indicate that WT1 is a promising prognostic biomarker and facilitates PTC progression and development of cells carrying the BRAFV600E mutation.

TIFAB accelerates MLL-AF9-Induced acute myeloid leukemia through upregulation of HOXA9

We previously showed stabilization of NIK-induced activation of NF-κB non-canonical signaling suppresses MLL-AF9-induced AML. In the current study, we demonstrate that deletion of NF-κB non-canonical RelB prevents the inhibitory effect of NIK stabilization in MLL-AF9 AML. Mechanistically, RelB suppresses its direct target, TIFAB, which is upregulated in human AML and correlates negatively with the survival of AML patients. Forced expression of TIFAB reverses NIK-induced impaired AML development through downregulation of RelB and upregulation of HOXA9. Consistent with upregulation of HOXA9, gene set enrichment analysis shows that forced expression of TIFAB blocks myeloid cell development, upregulates leukemia stem cell signature and induces similar gene expression patterns to those of HOXA9-MEIS1 and HOXA9-NUP98, and upregulates oxidative phosphorylation. Accordingly, forced expression of HOXA9 also largely releases the inhibitory impact of NIK stabilization via downregulation of RelB and upregulation of RelA. Our data suggest that NIK/RelB suppresses MLL-AF9-induced AML mainly through downregulation of TIFAB/HOXA9.

Identification of key genes in cutaneous squamous cell carcinoma: a transcriptome sequencing and bioinformatics profiling study

Background

Long-term exposure to ultraviolet (UV) radiation can cause cutaneous squamous cell carcinoma (cSCC), which is one of the most common malignant cancers worldwide. Actinic keratosis (AK) is generally considered a precancerous lesion of cSCC. However, the pathogenesis and oncogenic processes of AK and cSCC remain elusive, especially in the context of photodamage.

Methods

In this study, transcriptome sequencing was performed on AK, cSCC, normal sun-exposed skin (NES) tissues, and normal non-sun-exposed skin (NNS) from 24 individuals. Bioinformatics analysis to identify the differentially expressed genes (DEGs) of 4 groups, and potential key genes of cSCC were validated by real-time quantitative reverse transcription PCR (qRT-PCR).

Results

A total of 46,930 genes were differentially expressed in the 4 groups, including 127 genes that were differentially expressed between NES and NNS, 420 DEGs in AK compared to NES, 1,658 DEGs in cSCC compared to NES, and 1,389 DEGs in cSCC compared to AK. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis suggested that the DEGs are involved in multiple pathways, including extracellular matrix (ECM)-receptor interaction, immune, inflammatory, microbial infection, and other related pathways. Finally, 5 new genes (HEPHL1, FBN2, SULF1, SULF2, and TCN1) were confirmed significantly upregulated in cSCC.

Conclusions

Using transcriptome sequencing and integrated bioinformatical analysis, we have identified key DEGs and pathways in cSCC, which could improve our understanding of the cause and underlying molecular events of AK and cSCC. HEPHL1, FBN2, SULF1, SULF2, and TCN1 may be novel potential biomarkers and therapeutic targets of cSCC.

PURPL represses autophagic cell death to promote cutaneous melanoma by modulating ULK1 phosphorylation

Uncontrolled overactivation of autophagy may lead to autophagic cell death, suppression of which is a pro-survival strategy for tumors. However, mechanisms involving key regulators in modulating autophagic cell death remain poorly defined. Here, we report a novel long noncoding RNA, p53 upregulated regulator of p53 levels (PURPL), functions as an oncogene to promote cell proliferation, colony formation, migration, invasiveness, and inhibits cell death in melanoma cells. Mechanistic studies showed that PURPL promoted mTOR-mediated ULK1 phosphorylation at Ser757 by physical interacting with mTOR and ULK1 to constrain autophagic response to avoid cell death. Loss of PURPL led to AMPK-mediated phosphorylation of ULK1 at Ser555 and Ser317 to over-activate autophagy and induce autophagic cell death. Our results identify PURPL as a key regulator to modulate the activity of autophagy initiation factor ULK1 to repress autophagic cell death in melanoma and may represent a potential intervention target for melanoma therapy.

Molecular implications of HOX genes targeting multiple signaling pathways in cancer

Homeobox (HOX) genes encode highly conserved homeotic transcription factors that play a crucial role in organogenesis and tissue homeostasis. Their deregulation impacts the function of several regulatory molecules contributing to tumor initiation and progression. A functional bridge exists between altered gene expression of individual HOX genes and tumorigenesis. This review focuses on how deregulation in the HOX-associated signaling pathways contributes to the metastatic progression in cancer. We discuss their functional significance, clinical implications and ascertain their role as a diagnostic and prognostic biomarker in the various cancer types. Besides, the mechanism of understanding the theoretical underpinning that affects HOX-mediated therapy resistance in cancers has been outlined. The knowledge gained shall pave the way for newer insights into the treatment of cancer.

Integrated tissue proteome and metabolome reveal key elements and regulatory pathways in cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (CSCC) is a widespread malignancy but has a very low long-term survival rate for patients at the metastatic stage. Therefore, it is urgent to identify prognostic biomarkers for CSCC and improve our understanding of disease progression. Here we took advantage of a data-independent acquisition (DIA)-based nano liquid chromatography equipped with an orbitrap mass spectrometry (nLC-MS/MS) and ultraperformance LC coupled to a time-of-flight tandem MS (UPLC-TOF-MS/MS) technique to analyze cancer and corresponding noncancerous tissues from 20 CSCC patients for integrated proteomic and metabolomic analyses. Overall, 6241 tissue proteins were detected, while 136 proteins were significantly expressed in CSCC tissues. Further functional analysis revealed that various biological processes were highly enriched and participated in the pathogenesis of CSCC, especially DNA damage responses. Moreover, 641 named metabolites in total were identified, among which 181 were significantly changed in CSCC tissues. A total of 101 pathways were significantly enriched including apoptosis, autophagy, PI3K-Akt and mTOR signaling pathways. Interestingly, two pathways, protein digestion & absorption and platelet activation were both enriched in proteomic and metabolomic studies involving 5 proteins and 11 metabolites. Accordingly, a four-metabolite panel consisting of arachidonate, glutamine, glutamic acid, and proline (all area under the curve (AUC) values more than 0.9) was developed with a high accuracy (0.971) to distinguish the 20 detected cancer tissues from their noncancerous tissues. Collectively, our work highlighted the key elements and regulatory pathways involved in the pathogenesis of CSCC. More importantly, the present study not only provided potential biomarkers for the early diagnosis of CSCC, but also expanded our knowledge of the physiopathology of the disease. SIGNIFICANCE: CSCC is the second most common human cancer but has few treatment options and few sensitive biomarkers for diagnosis. Here we comprehensively revealed its molecular characteristics by performing integrated tissue proteomic and metabolomic analyses. Significantly distinct profiles and certain enriched pathways including DNA damage responses were identified as associated with CSCC. Moreover, protein digestion & absorption and platelet activation were both enriched in the proteome and metabolome. These identified molecular changes probably play significant roles in CSCC development. Finally, we developed a four-metabolite panel to distinguish CSCC with high accuracy. Overall, our data not only provided potential diagnostic biomarkers, but also extended knowledge on the pathogenesis of CSCC.

Analysis of HOX gene expression and the effects of HOXA9 overexpression in fibroblasts derived from keloid lesions and normal skin

Keloids are fibroproliferative lesions resulting from an abnormal wound healing process due to pathological mechanisms that remain incompletely understood. Keloids tend to occur more frequently in anterior versus posterior body regions (e.g., ears, face, upper torso); this has been attributed to higher skin tension in those areas, although this has not yet been conclusively proven. Previous studies reported reduced expression of multiple homeobox (HOX) genes in keloid versus normal fibroblasts, suggesting a role for HOX genes in keloid pathology. However, HOX genes are differentially expressed along the anterior-posterior axis. Hypothetically, differential HOX expression may be due to differences in body sites, as matched donor sites are often unavailable for keloids and normal skin. To better understand the basis for differential HOX gene expression in cells from keloids compared with normal skin, we compared HOXA7, HOXA9, HOXC8 and HOXC11 expression in keloid and normal skin-derived fibroblasts from various body sites. When keloid (N = 20) and normal (N = 12) fibroblast cell strains were evaluated, expression of HOXA7, HOXA9 and HOXC8 was significantly lower in keloid versus normal fibroblasts. However, HOX gene expression was lower in fibroblasts from more anterior versus posterior body sites. When keloid and normal cells from similar body sites were compared, differential HOX expression was not observed. To investigate the phenotypic relevance of HOX expression, HOXA9 was overexpressed in keloid and normal fibroblasts. HOXA9 overexpression did not affect proliferation but significantly reduced fibroblast migration and altered gene expression. The results suggest that differential HOX expression may be due to differences in positional identity between keloid and normal fibroblasts. However, HOX genes can potentially regulate fibroblast phenotype, suggesting that differential HOX gene expression may play a role in keloid development in anterior body sites.

Overexpression of HOXA9 upregulates NF-κB signaling to promote human hematopoiesis and alter the hematopoietic differentiation potentials

Background

The HOX genes are master regulators of embryogenesis that are also involved in hematopoiesis. HOXA9 belongs to a cluster of HOX genes that play extensively studied roles in hematopoiesis and leukemogenesis.

Methods

We established HOXA9-inducible human embryonic stem cells (HOXA9/hESCs) with normal pluripotency and potential for hematopoiesis, which could be used to analyze gene function with high accuracy. HOXA9/hESCs co-cultured with aorta–gonad–mesonephros-derived stromal cells (AGM-S3) were induced to overexpress HOXA9 with doxycycline (DOX) at various times after hematopoiesis started and then subjected to flow cytometry.

Results

Induction of HOXA9 from Day 4 (D4) or later notably promoted hematopoiesis and also increased the production of CD34+ cells and derived populations. The potential for myelogenesis was significantly elevated while the potential for erythrogenesis was significantly reduced. At D14, a significant promotion of S phase was observed in green fluorescent protein positive (GFP+) cells overexpressing HOXA9. NF-κB signaling was also up-regulated at D14 following induction of HOXA9 on D4. All of these effects could be counteracted by addition of an NF-κB inhibitor or siRNA against NFKB1 along with DOX.

Conclusions

Overexpression of HOXA9 starting at D4 or later during hematopoiesis significantly promoted hematopoiesis and the production of myeloid progenitors while reduced the production of erythroid progenitors, indicating that HOXA9 plays a key role in hematopoiesis and differentiation of hematopoietic lineages.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13619-020-00066-0.

The role of Irisin in multiorgan protection

Physical exercise is an effective strategy for improving human health. Various organs, including the heart, lung and kidney, can benefit from exercise. However, the underlying molecular mechanisms by which exercise protects organs remain unknown. Irisin, a myokine secreted from muscle in response to exercise, has attracted increased attention from researchers. The role of irisin in multiorgan protection has been gradually revealed, and this muscle-derived circulating factor is regarded as an essential bridge linking exercise and organ health. The mechanisms by which irisin protects diverse organs are different. Here, we review the research progress on the multiorgan protective effects of irisin and discuss the underlying molecular mechanisms.

HOX genes and the NF-κB pathway: A convergence of developmental biology, inflammation and cancer biology

The roles of HOX transcription factors as oncogenes and tumor suppressor genes, and the NF-KB pathway in chronic inflammation, both leading to cancer are well-established. HOX transcription factors are members of an evolutionarily conserved family of proteins required for anteroposterior body axis patterning during embryonic development, and are often dysregulated in cancer. The NF-KB pathway aids inflammation and immunity but it is also important during embryonic development. It is frequently activated in both solid and hematological malignancies. NF-KB and HOX proteins can influence each other through mutual transcriptional regulation, protein-protein interactions, and regulation of upstream and downstream interactors. These interactions have important implications both in homeostasis and in disease. In this review, we summarize the role of HOX proteins in regulating inflammation in homeostasis and disease- with a particular emphasis on cancer. We also describe the relationship between HOX genes and the NF-KB pathway, and discuss potential therapeutic strategies.

Modulation of HOXA9 after skeletal muscle denervation and reinnervation

Homeobox A9 (HOXA9), the expression of which is promoted by mixed lineage leukemia 1 (MLL1) and WD-40 repeat protein 5 (WDR5), is a homeodomain-containing transcription factor that plays an essential role in regulating stem cell activity. HOXA9 has been found to inhibit skeletal muscle regeneration and delay recovery after muscle wounding in aged mice, but little is known about its role in denervated/reinnervated muscles. We performed detailed time-dependent expression analyses of HOXA9 and its promoters, MLL1 and WDR5, in rat gastrocnemius muscles after the following three types of sciatic nerve surgeries: nerve transection (denervation), end-to-end repair (repair), and sham operation (sham). Then, the specific mechanisms of HOXA9 were detected in vitro by transfecting primary satellite cells with empty pIRES2-DsRed2, pIRES2-DsRed2-HOXA9, empty pPLK/GFP-Puro, and pPLK/GFP-Puro-HOXA9 small hairpin RNA (shRNA) plasmids. We found, for the first time, that HOXA9 protein expression simultaneously increased with increasing denervated muscle atrophy severity and that upregulated MLL1 and WDR5 expression was partly associated with denervation. Indeed, in vitro experiments revealed that HOXA9 inhibited myogenic differentiation, affected the best known atrophic signaling pathways, and promoted apoptosis but did not eliminate the differentiation potential of primary satellite cells. HOXA9 may promote denervated muscle atrophy by regulating the activity of satellite cells.