Knockdown of High Mobility Group-Box 3 (HMGB3) Expression Inhibits Proliferation, Reduces Migration, and Affects Chemosensitivity in Gastric Cancer Cells

circRNA TATA-box binding protein associated factor 15 acts as an oncogene to facilitate bladder cancer progression through targeting miR-502-5p/high mobility group box 3

Circular RNAs (circRNAs) are key in regulating bladder cancer progression. This study explored the effects of circRNA TATA-box binding protein associated factor 15 (circTAF15) on bladder cancer progression. We enrolled 80 bladder cancer patients to examine the relationship between circTAF15 expression and clinical features. The function of circTAF15 on bladder cancer cell viability, proliferation, migration, invasion, and glycolysis was monitored by cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine experiment, Transwell experiment, and glycolysis analysis. Dual luciferase reporter gene assay, RNA pull-down assay, and RNA immunoprecipitation assay were used to verify the binding between circTAF15 and miR-502-5p or between miR-502-5p and high mobility group box 3 (HMGB3). circTAF15 effect on in vivo growth of bladder cancer was investigated by xenograft tumor experiment. Quantitative real-time polymerase chain reaction, Western blot, and immunohistochemistry were implemented to investigate the expression levels of genes. circTAF15 was upregulated in bladder cancer patients, associated with unfavorable outcomes. circTAF15 knockdown attenuated bladder cancer cell viability, proliferation, migration, invasion, epithelial-mesenchymal transition, and glycolysis. circTAF15 suppressed miR-502-5p expression, and miR-502-5p inhibited HMGB3 expression. Low miR-502-5p expression was associated with unfavorable outcomes in bladder cancer patients. miR-502-5p silencing and HMGB3 overexpression counteracted the inhibition of circTAF15 knockdown on the malignant phenotype of bladder cancer cells. circTAF15 knockdown attenuated the in vivo growth of bladder cancer cells. circTAF15 enhanced the progression of bladder cancer through upregulating HMGB3 via suppressing miR-502-5p. circTAF15 may be a novel target to treat bladder cancer in the future.

Circ_LDLR promotes the progression of papillary thyroid carcinoma by regulating miR-1294/HMGB3 axis

Circular RNAs (circRNAs) have been found to be associated with the development and progression of cancers including papillary thyroid carcinoma (PTC). Circ_LDLR has been reported to be highly expressed in PTC, but its underlying mechanism of action has not been fully elucidated. This study aimed to investigate the role of circ_LDLR in PTC. The expression of circ_LDLR, miR-1294 and high mobility group box (HMGB) 3 was detected by quantitative real-time polymerase chain reaction (qRT-PCR). CCK-8 assay and transwell assays were employed to value cell viability, invasion and migration abilities. Western blot assay was to detect HMGB3 protein expression. Luciferase reporter gene and pull down assay were used to validate the interaction between miR-1294 and HMGB3 or circ_LDLR. Circ_LDLR showed high expression levels in PTC tissues and cells and knockdown of it inhibited the growth, invasion, and migration of PTC cells. In addition, miR-1294 was considered as a downstream target of circ_LDLR, and inhibition of miR-1294 partially reversed the inhibitory effects of circ_LDLR knockdown on PTC cells growth, invasion, and migration. More importantly, HMGB3 was identified as a downstream target of miR-1294. Our findings suggest circ_LDLR may plays a promoting role in PTC by downregulating miR-1294 and upregulating HMGB3 expression. Therefore, circ_LDLR may serve as a valuable prognostic biomarker and therapeutic target for PTC.

Expression, tumor immune infiltration, and prognostic impact of HMGs in gastric cancer

Background

In the past decade, considerable research efforts on gastric cancer (GC) have been expended, however, little advancement has been made owing to the lack of effective biomarkers and treatment options. Herein, we aimed to examine the levels of expression, mutations, and clinical relevance of HMGs in GC to provide sufficient scientific evidence for clinical decision-making and risk management.

Methods

GC samples were obtained from The Cancer Genome Atlas (TCGA). University of California Santa Cruz (UCSC) XENA, Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, cBioPortal, GeneMANIA, STRING, LinkedOmics, and DAVID databases were employed. The "ggplot2" package in the R software (×64 3.6.3) was used to thoroughly analyze the effects of HMGs. qRT-PCR was performed to assess HMG levels in GC cell lines.

Results

A total of 375 GC tissues and 32 paraneoplastic tissues were analyzed. The levels of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN1, HMGN2, and HMGN4 expression were increased in GC tissues relative to normal gastric tissues. HMGA1, HMGA2, HMGB1, HMGB2, and HMGB3 were highly expressed in GC cell lines. The OS was significantly different in the group showing low expressions of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN2, HMGN3, and HMGN5. There was a significant difference in RFS between the groups with low HMGA2, HMGB3, and high HMGN2 expression. The levels of HMGA2, HMGB3, and HMGN1 had a higher accuracy for prediction to distinguish GC from normal tissues (AUC value > 0.9). HMGs were tightly associated with immune infiltration and tumor immune escape and antitumor immunity most likely participates in HMG-mediated oncogenesis in GC. GO and KEGG enrichment analyses showed that HMGs played a vital role in the cell cycle pathway.

Conclusions

Our results strongly suggest a vital role of HMGs in GC. HMGA2 and HMGB3 could be potential markers for prognostic prediction and treatment targets for GC by interrupting the cell cycle pathway. Our findings might provide renewed perspectives for the selection of prognostic biomarkers among HMGs in GC and may contribute to the determination of the optimal strategy for the treatment of these patients.

Longitudinal transcriptome analysis of cattle infected with Theileria parva

The apicomplexan cattle parasite Theileria parva is a major barrier to improving the livelihoods of smallholder farmers in Africa, killing over one million cattle on the continent each year. Although exotic breeds not native to Africa are highly susceptible to the disease, previous studies have illustrated that such breeds often show innate tolerance to infection by the parasite. The mechanisms underlying this tolerance remain largely unclear. To better understand the host response to T. parva infection we characterised the transcriptional response over 15 days in tolerant and susceptible cattle (n = 29) naturally exposed to the parasite. We identify key genes and pathways activated in response to infection as well as, importantly, several genes differentially expressed between the animals that ultimately survived or succumbed to infection. These include genes linked to key cell proliferation and infection pathways. Furthermore, we identify response expression quantitative trait loci containing genetic variants whose impact on the expression level of nearby genes changes in response to the infection. These therefore provide an indication of the genetic basis of differential host responses. Together these results provide a comprehensive analysis of the host transcriptional response to this under-studied pathogen, providing clues as to the mechanisms underlying natural tolerance to the disease.

HMGB3 Targeted by miR-145-5p Impacts Proliferation, Migration, Invasion, and Apoptosis of Breast Cancer Cells

This study focused on the investigation into how HMGB3 works in breast cancer (BC) progression. Firstly, we analyzed the relationship between HMGB3 and BC patients through the TCGA database. We performed qRT-PCR for determining the HMGB3 mRNA level and Western blot for detecting the protein level of HMGB3 in BC cell lines. CCK-8, flow cytometry, transwell, and wound healing assays were utilized to detect the effect of HMGB3 on BC cell phenotypes. Next, the prediction of the binding site shared by miR-145-5p and HMGB3 was performed by the bioinformatics method. The targeting relationship between miR-145-5p and HMGB3 was validated by using dual-luciferase assay. Finally, rescue experiments were employed for assessing the effect of the miR-145-5p/HMGB3 axis on BC cells. HMGB3 was demonstrated to have a high-level expression in BC cell lines and facilitated BC progression. On the contrary, miR-145-5p was shown a low-level expression in BC cell lines, which could target HMGB3. miR-145-5p restrained the proliferation, migration, and invasion of BC cells via inhibiting HMGB3.

MicroRNA-18 facilitates the stemness of gastric cancer by downregulating HMGB3 though targeting Meis2

The recurrence and metastasis of gastric cancer are related to the stemness of gastric cancer cells. Researches have shown that miR-18 level is negatively correlated to the occurrence and development of certain cancer types. However, the effects of miR-18 on the stemness of gastric cancer remain uncertain. In this research, gastric cancer cell lines with stable overexpression of miR-18 were constructed through lentivirus infection. CCK-8 assay, RT-qPCR, Western blot, flow cytometry, and in vivo tumorigenesis assays were performed to evaluate the effects of miR-18 on the stemness of gastric cancer cells. Moreover, luciferase reporter assays found that Meis2 was the target of miR-18. Furthermore, we also found that the low-expressed oncogene HMGB3 is involved in this miR-18/Meis2 axis to further promote the stemness of gastric cancer cells. These findings suggest that the miR-18/Meis2/HMGB3 axis may be potential prognostic indicators for patients with gastric cancer.

HMGB3 promotes PARP inhibitor resistance through interacting with PARP1 in ovarian cancer

Poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi) resistance remains a therapeutic challenge in ovarian cancer. High-mobility group box 3 (HMGB3) plays significant roles in the development of drug resistance of many cancers. However, the function of HMGB3 in PARPi resistance is poorly understood. In the current study, we clarified that HMGB3 was aberrantly overexpressed in high-grade serous ovarian carcinoma (HGSOC) tissues, and high HMGB3 levels indicated shorter overall survival and drug resistance in HGSOC. The overexpression of HMGB3 increased the insensitivity of ovarian cancer to PARPi, whereas HMGB3 knockdown reduced PARPi resistance. Mechanistically, PARP1 was identified as a novel interaction partner of HMGB3, which could be blocked using olaparib and was enhanced upon DNA damage conditions. We further showed that loss of HMGB3 induced PARP1 trapping at DNA lesions and inhibited the PARylation activity of PARP1, resulting in an increased DNA damage response and cell apoptosis. The PARPi-resistant role of HMGB3 was also verified in a xenograft mouse model. In conclusion, HMGB3 promoted PARPi resistance via interacting with PARP1, and the targeted inhibition of HMGB3 might overcome PARPi resistance in ovarian cancer therapy.

Regulation of closely juxtaposed proto-oncogene c-fms and HMGXB3 gene expression by mRNA 3' end polymorphism in breast cancer cells

Sense-antisense mRNA pairs generated by convergent transcription is a way of gene regulation. c-fms gene is closely juxtaposed to the HMGXB3 gene in the opposite orientation, in chromosome 5. The intergenic region (IR) between c-fms and HMGXB3 genes is 162 bp. We found that a small portion (∼4.18%) of HMGXB3 mRNA is transcribed further downstream, including the end of the c-fms gene generating antisense mRNA against c-fms mRNA. Similarly, a small portion (∼1.1%) of c-fms mRNA is transcribed further downstream, including the end of the HMGXB3 gene generating antisense mRNA against the HMGXB3 mRNA. Insertion of the strong poly(A) signal sequence in the IR results in decreased c-fms and HMGXB3 antisense mRNAs, resulting in up-regulation of both c-fms and HMGXB3 mRNA expression. miR-324-5p targets HMGXB3 mRNA 3' UTR, and as a result, regulates c-fms mRNA expression. HuR stabilizes c-fms mRNA, and as a result, down-regulates HMGXB3 mRNA expression. UALCAN analysis indicates that the expression pattern between c-fms and HMGXB3 proteins are opposite in vivo in breast cancer tissues. Together, our results indicate that the mRNA encoded by the HMGXB3 gene can influence the expression of adjacent c-fms mRNA, or vice versa.

LINC00319 promotes cancer stem cell-like properties in laryngeal squamous cell carcinoma via E2F1-mediated upregulation of HMGB3

Laryngeal squamous cell carcinoma (LSCC) is one of the most common subtypes of head and neck malignancies worldwide. Long intervening/intergenic noncoding RNAs (LINCRNAs) have been recently implicated in various biological processes that take place in the setting of laryngeal cancer, but the regulatory role of LINC00319 in LSCC remains largely unknown. The current study aimed to elucidate the regulatory effect of LINC00319 on the development and progression of LSCC via high-mobility group box 3 (HMGB3). Microarray-based analysis was initially conducted to identify differentially expressed long noncoding RNAs, after which the expression of LINC00319 and HMGB3 in LSCC tissues and cells was determined accordingly. CD133+CD144+ TU177 cells were subsequently isolated and transfected with LINC00319 overexpression vector (oe-LINC00319), short hairpin RNA (sh)-LINC00319, sh-HMGB3, sh-E2F transcription factor 1 (E2F1), and oe-E2F1, as well as their corresponding controls. The proliferative, invasion, self-renewal, and tumorigenic abilities of CD133+CD144+ TU177 cells were then evaluated. Our in vitro findings were further confirmed following subcutaneous injection of cells expressing the corresponding plasmids into nude mice. LINC00319 and HMGB3 expressions were elevated in LSCC cells and tissues. LINC00319 increased HMGB3 expression by recruiting E2F1. Furthermore, the stimulatory role of LINC00319 on the proliferation, invasion, self-renewal ability, and tumorigenicity of CD133+CD144+ TU177 cells was achieved by upregulating HMGB3 via recruitment of E2F1. The in vitro findings were also confirmed by in vivo experiments. Taken together, these data show that downregulating LINC00319 in CD133+CD144+ TU177 cells may serve as a potential anticancer regimen by inhibiting the proliferation and invasion of cancer stem cells in LSCC.

The role of microRNAs in epithelial to mesenchymal transition and cancers; focusing on mir-200 family

Epithelial to mesenchymal transition (EMT) is a process associated with cancer malignancy and metastases. Cells undergoing EMT lose their epithelial phenotype and acquire mesenchymal phenotype. This process is accompanied by several molecular changes such as decrease of E-cadherin and increase of N-cadherin which is called the "cadherin swich". MicroRNAs (miRNAs, miRs) are small non-coding RNAs having ability to regulate genes post-transcriptionally. Nowadays they are believed to take part in multiple physiological and pathological processes including cancer development. Comparison between TargetScan7 (www.targetscan.org) results for miR-200b and metanalysis of genes involved in EMT showed that miR-200b has a potential binding site in 60 genes that are involved in EMT (the majority of them were associated with mesenchymal phenotype). Our review summarizes literature findings contributing to experimentally proven interactions between miR-200b and genes involved in EMT process including cell receptors, signaling pathways, cell cycle or cell adhesion. The results of those interactions indicate that miR-200b may have an inhibitory impact on EMT or even in selected cases is able to restore epithelial phenotype.

MicroRNA-429 acts as a tumor suppressor in colorectal cancer by targeting high mobility group box 3

Colorectal cancer (CRC) is one of the most common solid tumors worldwide and has an extremely poor prognosis. MicroRNA-429 (miR-429) has been reported to participate in the progression of CRC. However, the pathological mechanisms require further investigation. The aim of the present study was to investigate the association between miR-429 and high mobility group box 3 (HMGB3) in CRC and the associated mechanism. The mRNA expression levels of miR-429 and HMGB3 in 65 paired CRC and adjacent tissues were examined by reverse transcription-quantitative PCR. Furthermore, a dual-luciferase reporter assay was performed to identify the association between miR-429 and HMGB3. Finally, the effects of miR-429 and HMGB3 on the proliferation and apoptosis of CRC cells were detected. As a result, it was identified that miR-429 expression was downregulated and HMGB3 expression was upregulated in CRC tissues compared with in adjacent non-cancer tissues, and the expression levels of miR-429 were negatively associated with those of HMGB3. Notably, HMGB3 was demonstrated to be a direct target of miR-429 by dual-luciferase reporter assay. Furthermore, transfection with a miR-429 mimic significantly inhibited HMGB3 expression and led to decreased proliferation and increased apoptosis of CRC cells. On the other hand, transient overexpression of HMGB3 partially inhibited the antitumor effects of miR-429. To the best of our knowledge, the present study demonstrated for the first time that miR-429 regulated the proliferation and apoptosis of CRC cells via HMGB3, suggesting a specific tumor suppressive function of the miR-429/HMGB3 signaling pathway in CRC.

The role of high mobility group protein B3 (HMGB3) in tumor proliferation and drug resistance

The high mobility group protein B (HMGB) family (including HMGB1, HMGB2, HMGB3, and HMGB4) can regulate the mechanisms of DNA replication, transcription, recombination, and repair, and act as cytokines to mediate responses to infection, injury, and inflammation. HMGB1/2/3 has a high similarity in sequence and structure, while HMGB4 has no acidic C-terminal tail. Among them, HMGB3 can regulate the self-renewal and differentiation of normal hematopoietic stem cell population, but the decrease of its expression is easy to induce leukemia. Up-regulation of its expression promotes tumor development and chemotherapy resistance through a variety of mechanisms, and non-coding RNA can regulate to promote tumor cell proliferation, invasion, and migration and inhibit cancer cell apoptosis.

Biological functions and theranostic potential of HMGB family members in human cancers

The high mobility group box (HMGB) protein family consists of four members: HMGB1, 2, 3, and 4. They share similar amino acid sequences and identical functional regions, especially HMGB1, 2, and 3. The homology in structure may lead to similarity in function. In fact, though their targets may be different, they all possess the fundamental function of binding and distorting target DNAs. However, further research confirmed they are distributed differently in tissues and involved in various distinct physiological and pathological cellular processes, including cell proliferation, division, migration, and differentiation. Recently, the roles of HMGB family members in carcinogenesis has been widely investigated; however, systematic discussion on their functions and clinical values in malignant tumors is limited. In this review, we mainly review and summarize recent advances in knowledge of HMGB family members in terms of structure, distribution, biochemical cascades, and specific mechanisms regarding tumor progression. Importantly, the diagnostic, prognostic, and therapeutic value of these proteins in cancers is discussed. Finally, we envisage the orientation and challenges of this field in further studies.

Long Noncoding RNA SOX2-OT Knockdown Inhibits Proliferation and Metastasis of Prostate Cancer Cells Through Modulating the miR-452-5p/HMGB3 Axis and Inactivating Wnt/β-Catenin Pathway

Background: Recent studies have proven that abnormal expression of long noncoding RNAs (lncRNAs) often contributes to growth and invasion of cancer cells. The purpose of this study was to investigate the biological function and regulatory mechanism of lncRNA SOX2 overlapping transcript (SOX2-OT) in prostate cancer (PCa) progression. Materials and Methods: The expression of SOX2-OT, microRNA-452-5p (miR-452-5p), and high mobility group box 3 (HMGB3) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was performed to determine the cell cycle distribution. Western blot assay was conducted to measure the protein levels of cyclin D1, p21, p27, E-cadherin, vimentin, and N-cadherin. The interaction between miR-452-5p and SOX2-OT or HMGB3 was predicted by bioinformatics analysis and verified by dual-luciferase reporter assay and RNA immunoprecipitation assay. The mice xenograft model was established to investigate the role of SOX2-OT in vivo. Results: SOX2-OT and HMGB3 were upregulated, whereas miR-452-5p was downregulated in PCa tissues and cells. Knockdown of SOX2-OT inhibited PCa cell growth and metastasis. MiR-452-5p could directly bind to SOX2-OT and its knockdown reversed the inhibitory effects of SOX2-OT interference on growth and metastasis of PCa cells. HMGB3 was a direct target of miR-452-5p and its knockdown weakened the promotive effects of miR-452-5p silence on growth and metastasis of PCa cells. Moreover, HMGB3 expression was inversely regulated by miR-452-5p and positively modulated by SOX2-OT. Furthermore, SOX2-OT activated the Wnt/β-catenin signaling pathway through increasing HMGB3 expression. Finally, SOX2-OT knockdown hindered tumor growth in vivo by regulating miR-452-5p/HMGB3 axis. Conclusions: SOX2-OT downregulation limited PCa cell growth and metastasis by regulating miR-452-5p/HMGB3 axis and inactivating Wnt/β-catenin signaling pathway, which might offer lncRNA-directed diagnosis and therapy for PCa.

Targeting Chromosomal Architectural HMGB Proteins Could Be the Next Frontier in Cancer Therapy

Chromatin-associated architectural proteins are part of a fundamental support system for cellular DNA-dependent processes and can maintain/modulate the efficiency of DNA replication, transcription, and DNA repair. Interestingly, prognostic outcomes of many cancer types have been linked with the expression levels of several of these architectural proteins. The high mobility group box (HMGB) architectural protein family has been well studied in this regard. The differential expression levels of HMGB proteins and/or mRNAs and their implications in cancer etiology and prognosis present the potential of novel targets that can be explored to increase the efficacy of existing cancer therapies. HMGB1, the most studied member of the HMGB protein family, has pleiotropic roles in cells including an association with nucleotide excision repair, base excision repair, mismatch repair, and DNA double-strand break repair. Moreover, the HMGB proteins have been identified in regulating DNA damage responses and cell survival following treatment with DNA-damaging agents and, as such, may play roles in modulating the efficacy of chemotherapeutic drugs by modulating DNA repair pathways. Here, we discuss the functions of HMGB proteins in DNA damage processing and their potential roles in cancer etiology, prognosis, and therapeutics.

LncRNA SNHG5 promotes nasopharyngeal carcinoma progression by regulating miR-1179/HMGB3 axis

Background

Long noncoding RNAs (lncRNAs) have been reported to be important regulators in pathogenesis of human cancers, including nasopharyngeal carcinoma (NPC). Here, we mainly aimed to explore the mechanisms of LncRNA-SNHG5/ miR-1179/HMGB3 axis in NPC progression.

Methods

RT-qPCR and Western blot analysis were employed to detect mRNA and protein expressions. CCK-8, Transwell and dual luciferase reporter assays were applied to investigate functions of LncRNA-SNHG5/miR-1179/HMGB3 axis.

Results

Upregulation of lncRNA-SNHG5 and downregulation of miR-1179 were identified in NPC, which were associated with adverse clinical outcomes. Functionally, upregulation of lncRNA-SNHG5 and downregulation of miR-1179 accelerated NPC cell proliferation, migration and invasion. Furthermore, lncRNA-SNHG5 acted as a molecular sponge of miR-1179 in NPC. Besides that, upregulation of HMGB3 was found in NPC, and knockdown of HMGB3 restrained NPC progression. Moreover, HMGB3, a target of miR-1179, regulated NPC progression by mediating LncRNA-SNHG5/miR-1179 axis.

Conclusion

LncRNA SNHG5 serves as a tumor promoter in NPC by sponging miR-1179 and upregulating HMGB3.

Bioinformatics analysis of the prognosis and biological significance of HMGB1, HMGB2, and HMGB3 in gastric cancer

High mobility group box (HMGB) consists primarily of HMGB1, HMGB2, and HMGB3 proteins. Although abnormal HMGB expression is associated with various tumors, the relationship with gastric cancer (GC) remains unclear. In this study, HMGB1, HMGB2, and HMGB3 expression was analyzed using the Oncomine and TCGA databases. Correlations between HMGB1, HMGB2, and HMGB3 and clinicopathological factors were analyzed. cBioPortal was used to analyze HMGB1, HMGB2, and HMGB3 genetic alterations and its gene regulation network in GC tissue. HMGB1, HMGB2, and HMGB3 expression was higher in tumor tissues than in normal tissues, especially in GC. High HMGB1, HMGB2, and HMGB3 expression may predict a poor prognosis among patients with GC (hazard ratios [HR] = 1.90; 95% confidence interval [CI]: [1.30-2.78]) and human digestive system neoplasm (HR = 1.85; 95% CI [1.64-2.10]). These findings suggest that HMGB1, HMGB2, and HMGB3 may be useful prognostic indicators for patients with GC.

Integrated analysis of 10 lymphoma datasets identifies E2F8 as a key regulator in Burkitt's lymphoma and mantle cell lymphoma

Burkitt's lymphoma (BURK), diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) are three main types of B-cell lymphomas. This study aimed to compare the differences of affected biological functions and pathways, as well as to explore the possible regulatory mechanisms and the potential therapeutic targets in BURK, DLBCL and MCL. We performed an integrated analysis of 10 lymphoma datasets including 352 BURK patients, 880 DLBCL patients, 216 MCL patients, and 33 controls. Our results showed that signaling pathways, amino acid metabolism and several lipid metabolism pathways varies considerably among these three types of lymphoma. Furthermore, we identified several key transcription factors (TFs) and their target genes that may promote these diseases by influencing multiple carcinogenic pathways. Among these TFs, we reported first that E2F8 displayed the most significant effects in BURK and MCL. Our results demonstrate that over-expression of E2F8 activates target genes that may promote cell cycle, mitosis, immune and other cancer related functions in BURK and MCL. Therefore, we suggest that E2F8 could be used as a biomarker and potential therapeutic target for BURK and MCL. These findings would be helpful in the study of pathogenesis, and drug discovery and also in the prognosis of B cell lymphomas.

Ovarian cancer-derived exosomes promote tumour metastasis in vivo: an effect modulated by the invasiveness capacity of their originating cells

Exosomes are small nanovesicles that carry bioactive molecules which can be delivered to neighbouring cells to modify their biological functions. Studies have showed that exosomes from ovarian cancer (OVCA) cells can alter the cell migration and proliferation of cells within the tumour microenvironment, an effect modulated by the invasiveness capacity of their originating cells. Using an OVCA cell line xenograph mouse model, we showed that exosomes derived from a high invasiveness capacity cell line (exo-SKOV-3) promoted metastasis in vivo compared with exosomes from a low invasiveness capacity cell line (exo-OVCAR-3). Analysis from anin vivo imaging system (IVIS) revealed that exo-SKOV-3 formed metastatic niches, whereas exo-OVCAR-3 formed colonies of clustered cells close to the site of injection. Interestingly, kinetic parameters showed that the half-maximal stimulatory time (ST₅₀) of tumour growth with exo-OVCAR-3 (4.0 ± 0.31 weeks) was significantly lower compared with the ST₅₀ in mice injected with exo-SKOV-3 (4.5 ± 0.32 weeks). However, the number of metastic nodes in mice injected with exo-SKOV-3 was higher compared with exo-OVCAR-3. Using a quantitative mass spectrometry approach (SWATH MS/MS) followed by bioinformatics analysis using the Ingenuity Pathway Analysis (IPA), we identified a total of 771 proteins. Furthermore, 40 of these proteins were differentially expressed in tumour tissues from mice injected with exo-SKOV-3 compared with exo-OVCAR-3, and associated with Wnt canonical pathway (β-catenin). Finally, we identified a set of proteins which had elevated expression in the circulating exosomes in association with tumour metastasis. These observations suggest that exosomal signalling plays an important role in OVCA metastasis.

Overexpression of miR-758 inhibited proliferation, migration, invasion, and promoted apoptosis of non-small cell lung cancer cells by negatively regulating HMGB

Non-small cell lung cancer (NSCLC) is one of the most fatal types of cancer with significant mortality and morbidity worldwide. MicroRNAs (miRs) have been confirmed to have positive functions in NSCLC. In the present study, we try to explore the role of miR-758 in proliferation, migration, invasion, and apoptosis of NSCLC cells by regulating high-mobility group box (HMGB) 3 (HMGB3.) NSCLC and adjacent tissues were collected. Reverse transcription quantitative PCR (RT-qPCR) was employed to detect expression of miR-758 and HMGB3 in NSCLC and adjacent tissues, in BEAS-2B cells and NSCLC cell lines. The targetted relationship between miR-758 and HMGB3 was identified by dual luciferase reporter gene assay. The effects of miR-758 on proliferation, migration, invasion, cell cycle, and apoptosis of A549 cells. MiR-758 expression was lower in NSCLC tissues, which was opposite to HMGB3 expression. The results also demonstrated that miR-758 can target HMGB3. The cells transfected with miR-758 mimic had decreased HMGB3 expression, proliferation, migration, and invasion, with more arrested cells in G₁ phase and increased apoptosis. Our results supported that the overexpression of miR-758 inhibits proliferation, migration, and invasion, and promotes apoptosis of NSCLC cells by negative regulating HMGB2. The present study may provide a novel target for NSCLC treatment.

Knockdown of high mobility group box 3 impairs cell viability and colony formation but increases apoptosis in A549 human non-small cell lung cancer cells

Previous research has linked high mobility group box 3 (HMGB3) overexpression to the malignant progression and poor prognosis of non-small cell lung cancer (NSCLC). The present study investigated the role of HMGB3 in cell survival and colony formation of NSCLC cells. Stable knockdown of HMGB3 in A549 cells was achieved by lentiviral-based shRNA interference and verified by detection of the transcriptional and translational level of HMGB3 with reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The influence of HMGB3 knockdown on A549 cell viability and apoptotic rate was evaluated by Cell Counting Kit-8 assay and flow cytometry following annexin V staining, respectively. The proliferative capacity of A549 cells with or without HMGB3 knockdown was compared by measuring their colony forming efficiency. The results of the current study revealed that HMGB3 knockdown significantly reduced cell viability and colony forming efficiency while promoting apoptosis in A549 cells, indicating that HMGB3 may be pivotal for the survival and colony formation of A549 cells, serving a notable role in NSCLC progression.

Downregulation of microRNA-532-5p promotes the proliferation and invasion of bladder cancer cells through promotion of HMGB3/Wnt/β-catenin signaling

Accumulating evidence has shown that altered expression of microRNA-532-5p (miR-532-5p) is involved in the development and progression of various cancers. However, little is known about the role of miR-532-5p in bladder cancer. In this study, we aimed to investigate the expression, biological function, and regulatory mechanism of miR-532-5p in bladder cancer. Herein, we found that miR-532-5p expression was frequently downregulated in bladder cancer tissues and cell lines compared with normal controls. Functional experiments showed that overexpression of miR-532-5p inhibited the proliferation and invasion of bladder cancer cells, whereas inhibition of miR-532-5p showed opposite effects. Interestingly, bioinformatics analysis predicted high-mobility group protein B3 (HMGB3) as a potential target gene of miR-532-5p. Further experiments showed that miR-532-5p directly targeted the 3'-UTR of HMGB3 and negatively regulated its expression in bladder cancer cells. Moreover, HMGB3 expression was upregulated in bladder cancer tissues and showed inverse correlation with miR-532-5p expression. Notably, miR-532-5p regulated the nuclear expression of β-catenin and activation of Wnt/β-catenin signaling in bladder cancer cells. However, restoration of HMGB3 expression partially reversed the antitumor effect of miR-532-5p overexpression, while knockdown of HMGB3 partially abrogated the oncogenic effect of miR-532-5p inhibition. Taken together, our results demonstrated that miR-532-5p inhibited the proliferation and invasion of bladder cancer cells by targeting HMGB3 and downregulating Wnt/β-catenin signaling, suggesting a tumor suppressive role of miR-532-5p in bladder cancer. Our study highlights an importance of the miR-532-5p/HMGB3 axis in bladder cancer and suggests that targeting miR-532-5p/HMGB3 may have potential applications for development of bladder cancer therapy.

Effects of microRNA-513b on cell proliferation, apoptosis, invasion, and migration by targeting HMGB3 through regulation of mTOR signaling pathway in non-small-cell lung cancer

This study aimed to explore the underlying mechanism of miR-513b and HMGB3 in regulating non-small-cell lung cancer (NSCLC). NSCLC tumor, adjacent tissues, and cell lines were extracted, and the expression of miR-513b and HMGB3 were determined by quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analysis. Then, miR-513b was overexpressed in NSCLC cell, and the proliferation, migration, invasion, and apoptosis of cells were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), wound healing, transwell, and flow cytometry, respectively. Regulatory relationship between miR-513b and HMGB3 was determined using luciferase activity reporter assay. Lastly, HMGB3 and/or miR-513b were overexpressed in NSCLC cells, and the proliferation, migration, invasion, and apoptosis of cells were determined. Compared with the controls, the expression of miR-513b was significantly downregulated in the NSCLC tissues and cells lines by RT-qPCR ( p < 0.05). However, the expression of HMGB3 was significantly downregulated at both messenger RNA and protein levels ( p < 0.05). Overexpression of miR-513b could significantly inhibit the proliferation, invasion, migration, and promote apoptosis of NSCLC cells ( p < 0.05). HMGB3 was a target of miR-513b, and overexpression of HMGB3 could obviously reverse the effect of miR-513 on the proliferation, invasion, migration, and apoptosis of NSCLC cells ( p < 0.05). The present results could suggest miR-513b was downregulated in NSCLC and could regulate the proliferation, invasion, migration, and apoptosis of NSCLC cells via HMGB3.

High mobility group box 3 as an emerging biomarker in diagnosis and prognosis of hepatocellular carcinoma

Purpose

High mobility group box 3 (HMGB3) is associated with hepatocytes malignant transformation by our previous work. We continued to investigate the diagnostic and prognostic values of HMGB3 for hepatocellular carcinoma (HCC).

Patients and methods

Circulating HMGB3 levels were quantitatively detected in a cohort of 225 patients with chronic liver diseases by ELISA and compared with alpha-fetoprotein by the receiver operating characteristic curve. HMGB3 expression in tissues of 170 HCC was detected by tissue microarray and immunohistochemistry. Relationship between HMGB3 level and HCC prognosis was evaluated by the Kaplan-Meier curves and Cox regression model.

Results

The incidence of serum HMGB3 >2.0 ng/mL was 75.6% in HCC (96/127), 20.8% in liver cirrhosis (10/48), 16.0% in chronic hepatitis (8/50), and none in healthy controls (0/49). Significant difference (P<0.001) of circulating HMGB3 level was found between HCC and benign liver diseases. Total diagnostic sensitivity of serum HMGB3 plus alpha-fetoprotein was up to 89.0% for HCC. Higher HMGB3 expression was confirmed to be 73.5% in HCC tissues (125/170) >30.6% in their paracancerous tissues (52/170). HMGB3 expression was closely related to tumor size, TNM stage, poor survival, and high recurrence, suggesting an independent prognosis factor for HCC.

Conclusion

HMGB3 with aberrant expression could be a novel diagnostic and prognostic marker for HCC.

Abnormal expression of HMGB-3 is significantly associated with malignant transformation of hepatocytes

AIM

To explore the relationship between dynamic expression of high mobility group box-3 (HMGB3) and malignant transformation of hepatocytes.

METHODS

Expression of HMGB family proteins were observed in rat hepatocarcinogenesis models induced with 2-acetylaminofluorene. Alterations of HMGB3 were analyzed at the mRNA level by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and at the protein level by immunohistochemistry or Western blotting. HMGB3 in human liver cancer tissues were evaluated using bioinformatics databases from GEO, TCGA, and Oncomine. A specific HMGB3-shRNA was used to knock down HMGB3 expression in order to investigate its effects on proliferation and cell cycle in vitro and in vivo.

RESULTS

Elevated HMGB3 levels were first reported in hepatocarcinogenesis, with increasing expression from normal liver to cancer. Bioinformatic databases showed that HMGB3 expression in hepatocellular carcinoma tissues was significantly higher than that in normal liver tissues. Higher HMGB3 expression was discovered in liver cancer cells compared with LO2 cells in vitro. According to gene set enrichment analysis, HMGB3 mRNA levels were correlated with cell cycle and DNA replication pathways. Knocking down HMGB3 by specific shRNA significantly inhibited proliferation of HepG2 cells by cell cycle arrest and downregulating DNA replication related genes (cyclin B1, FEN1, and PCNA) at the mRNA and protein level. Furthermore, silencing HMGB3 significantly inhibited xenograft tumor growth (measured by Ki67) in vivo.

CONCLUSION

HMGB3 is involved in malignant transformation of hepatocytes and could be a useful biomarker for diagnosis and a potential target for therapy of liver cancer.

Hmgb3 Induces the Differentiation of Uterine Stromal Cells Through Targeting Ptn

Uterine decidualization is crucial for placenta formation and pregnancy maintenance. Although previous studies have reported that high mobility group box 3 (Hmgb3) is involved in the regulation of cellular proliferation and differentiation, little is known regarding its physiological role in uterine decidualization. Here, in situ hybridization result exhibited a dynamic expression pattern of Hmgb3 messenger RNA (mRNA) during early gestation, and it was mainly localized to the decidua on days 6 to 8 of gestation. Consistently, elevated Hmgb3 expression was noted in the decidualizing stromal cells after intraluminal oil infusion. In uterine luminal epithelium of ovariectomized mice, estrogen induced the accumulation of Hmgb3 mRNA, which was dependent on the existence of implanting blastocyst. Simultaneously, Hmgb3 could stimulate the proliferation of uterine stromal cells and promote the expression of Prl8a2, a reliable marker for stromal cell differentiation. Further analysis evidenced that Hmgb3 might modulate the expression of pleiotropin (Ptn) in uterine stromal cells. Moreover, silencing of Ptn could impede the upregulation of Prl8a2 elicited by Hmgb3 overexpression, while overexpression of Ptn reversed the repressive effects of Hmgb3 siRNA on Prl8a2 expression. Collectively, Hmgb3 may direct uterine decidualization through targeting Ptn.

Ginkgo biloba extract 761 enhances 5-fluorouracil chemosensitivity in colorectal cancer cells through regulation of high mobility group-box 3 expression

Although the standard ginkgo biloba extract EGb 761 exhibits antioxidative, anti-apoptotic, and anticancer properties, there is no research focusing on the chemopreventive effects of EGb 761 in colorectal cancer (CRC). The present study investigated whether EGb 761 could increase 5-fluorouracil (5FU) sensitivity in CRC and its potential mechanism. We found that combined EGb 761 and 5FU treatment significantly elevated the chemosensitivity of CRC cells to 5FU in 5FU-resistant (5FUR) CRC cells, whereas no obvious cytotoxicity of EGb 761 was observed in parental cells. Then, real-time PCR and western blotting revealed that EGb 761 notably attenuated drug resistance through inhibition of epithelial-mesenchymal transition (EMT) factors (increased E-cadherin and decreased vimentin). In addition, we found that EGb 761 significantly inhibited 5FU-induced upregulation of high mobility group-box 3 (HMGB3) expression in 5FUR CRC cells both at mRNA and protein levels. Knockdown of HMGB3 effectively reversed 5FU-induced EMT and attenuated 5FU-induced cytotoxicity in 5FUR CRC cells while overexpression of HMGB3 achieved the opposite results. Moreover, we found that knockdown of HMGB3 effectively reversed the EGb 761-induced inhibition of the Wnt/β-catenin pathway. The results of the current study collectively demonstrated that EGb 761 can chemosensitize 5FUR CRC cells by inhibiting an EMT phenotype via regulation of HMGB3 expression, suggesting it to be a novel chemoprotective agent in CRC.

HMGB3 modulates ROS production via activating TLR cascade in Apostichopus japonicus

High mobility group box protein 3 (HMGB3) regulates proliferation and inflammatory response in vertebrates. However, its functional roles in invertebrates are largely unknown. In this study, a HMGB3 homologue molecule was identified from Apostichopus japonicus (designated as AjHMGB3) by RACE approach. The full-length cDNA of AjHMGB3 was of 2298 bp with an open reading frame of 1320 bp encoding a 439-amino-acid (aa) residue protein. Structural analysis then conducted and the results revealed that AjHMGB3 processed two conserved HMGBs (133-204 and 210-279 aa) and an acidic tail. The results of subsequent multiple sequence alignment and phylogenetic analysis both indicated that AjHMGB3 belongs to a new member of HMGB3 protein subfamily. Furthermore, AjHMGB3 was expressed in all examined tissues except in tentacles and particularly highly expressed in the intestine, as indicated by spatial expression analysis results. The Vibrio splendidus challenge in vivo and lipolysaccharide (LPS) stimulation in vitro can significantly upregulate the mRNA expression of AjHMGB3 in coelomocytes. This finding is consistent with the expression profiles of TLR cascade members. We further investigated the expression profiles of AjMyD88 and Ajp105 after the gain- or loss-of-function of AjHMGB3 in coelomocytes. The results showed that AjMyD88 and Ajp105 were upregulated 2.19- and 2.83-fold in AjHMGB3 overexpressed treatment and downregulated 0.38- and 0.43-fold in the AjHMGB3 silencing group. The p50 subunit displayed expression profiles that are identical to those of AjMyD88 and Ajp105 according to the Western blot results. In the same condition, the respiratory burst was increased by 37.5% in the AjHMGB3 overexpressed group and depressed by 28.2% in the AjHMGB3 knock-down group. Our present findings collectively suggested that AjHMGB3 acted as an NF-κB activator and produced ROS production in sea cucumbers.

Dicer suppresses cytoskeleton remodeling and tumorigenesis of colorectal epithelium by miR-324-5p mediated suppression of HMGXB3 and WASF-2

Emerging evidence indicates that microRNAs, a class of small and well-conserved noncoding RNAs, participate in many physiological and pathological processes. RNase III endonuclease DICER is one of the key enzymes for microRNA biogenesis. Here, we found that DICER was downregulated in tumor samples of colorectal cancer (CRC) patients at both mRNA and protein levels. Importantly, intestinal epithelial cell (IEC)-specific deletion of Dicer mice got more tumors after azoxymethane and dextran sulfate sodium (DSS) administration. Interestingly, IEC-specific deletion of Dicer led to severe chronic inflammation and epithelium layer remodeling in mice with or without DSS administration. Microarray analysis of 3 paired Dicer deletion CRC cell lines showed that miR-324-5p was one of the most significantly decreased miRNAs. In the intestinal epithelium of IEC-specific deletion of Dicer mice, miR-324-5p was also found to be markedly reduced. Mechanistically, miR-324-5p directly bound to the 3′untranslated regions (3′UTRs) of HMG-box containing 3 (HMGXB3) and WAS protein family member 2 (WASF-2), two key proteins participated in cell motility and cytoskeleton remodeling, to suppress their expressions. Intraperitoneal injection of miR-324-5p AgomiR (an agonist of miR-324-5p) curtailed chronic inflammation and cytoskeleton remodeling of colorectal epithelium and restored intestinal barrier function in IEC-specific deletion of Dicer mice induced by DSS. Therefore, our study reveals a key role of a DICER/miR-324-5p/HMGXB3/WASF-2 axis in tumorigenesis of CRC by regulation of cytoskeleton remodeling and maintaining integrity of intestinal barriers.