Beta2-microglobulin promotes the growth of human renal cell carcinoma through the activation of the protein kinase A, cyclic AMP-responsive element-binding protein, and vascular endothelial growth factor axis

β2-microglobulin induced apoptosis of tumor cells via the ERK signaling pathway by directly interacting with HFE in HER2-overexpressing breast cancer

BACKGROUND

Our previous study demonstrated that β2-microglobulin (β2M) promoted ER+/HER2- breast cancer survival via the SGK1/Bcl-2 signaling pathway. However, the role of β2M has not been investigated in ER-/HER2+ breast cancer. Here, we aimed to determine the role of β2M in ER-/HER2+ breast cancer.

METHODS

The interaction between β2M and HFE was confirmed by co-immunoprecipitation, mass spectrometry, yeast two-hybrid screening, and His pull-down. The knockdown and overexpression of β2M or HFE were performed in MDA-MB-453 cells, and ERK signaling pathway was subsequently analyzed via western blotting. Apoptotic cells were detected using flow cytometer. β2M, HFE, and p-ERK1/2 were examined in tumor and paired adjacent tissues via immunohistochemistry.

RESULTS

HFE was found to be an interacting protein of β2M in ER-/HER2+ breast cancer cells MDA-MB-453 by co-immunoprecipitation and mass spectrometry. A yeast two-hybrid system and His-pull down experiments verified that β2M directly interacted with HFE. β2M and HFE as a complex were mainly located in the cytoplasm, with some on the cytomembrane of MDA-MB-453 cells. In addition to breast cancer cells BT474, endogenous β2M directly interacted with HFE in breast cancer cells MDA-MB-453, MDA-MB-231, and MCF-7. β2M activated the ERK signaling pathway by interacting with HFE and induced apoptosis of MDA-MB-453 cells. The expression of HFE and p-ERK1/2 showed significantly high levels in HER2-overexpressing breast cancer tumor tissue compared with adjacent normal tissue, consistent with the results obtained from the cell experiments.

CONCLUSIONS

β2M induced apoptosis of tumor cells via activation of the ERK signal pathway by directly interacting with HFE in HER2-overexpressing breast cancer.

The clinical significance and prognostic value of serum beta-2 microglobulin in adult lymphoma-associated hemophagocytic lymphohistiocytosis: a multicenter analysis of 326 patients

To investigate the prognostic impact of serum beta-2 microglobulin (B2M) in adult lymphoma-associated hemophagocytic lymphohistiocytosis (HLH). The clinical and laboratory characteristics of 326 adult patients in a multicenter cohort with lymphoma-associated HLH with available baseline serum B2M levels were retrospectively analyzed. A total of 326 cases were included in this study, and the median serum B2M level was 5.19 mg/L. The optimal cut-off of serum B2M was 8.73 mg/L, and the cases with serum B2M level >8.73 mg/L were older and had a more advanced stage, lower levels of platelets, albumin, and fibrinogen, and higher creatinine level. The serum B2M >8.73 mg/L, creatinine ≥133 μmol/L, fibrinogen ≤1.5 g/L, agranulocytosis (<0.5 × 109/L), severe thrombocytopenia (<50 × 109/L), and high Epstein-Barr virus DNA copy number were found to have independent prognostic values in all patients, and the serum B2M >8.73 mg/L was also an independent prognostic factor in patients with creatinine <133 μmol/L. Finally, a prognostic scoring system was established based on independent prognostic factors of all patients and categorized the patients into three groups with significant prognostic differences. This study confirmed that the serum B2M level can be an independent prognostic factor in lymphoma-associated HLH and established a prognostic scoring system to predict patients' survival.

Review of T cell proliferation regulatory factors in treatment and prognostic prediction for solid tumors

T cell proliferation regulators (Tcprs), which are positive regulators that promote T cell function, have made great contributions to the development of therapies to improve T cell function. CAR (chimeric antigen receptor) -T cell therapy, a type of adoptive cell transfer therapy that targets tumor cells and enhances immune lethality, has led to significant progress in the treatment of hematologic tumors. However, the applications of CAR-T in solid tumor treatment remain limited. Therefore, in this review, we focus on the development of Tcprs for solid tumor therapy and prognostic prediction. We summarize potential strategies for targeting different Tcprs to enhance T cell proliferation and activation and inhibition of cancer progression, thereby improving the antitumor activity and persistence of CAR-T. In summary, we propose means of enhancing CAR-T cells by expressing different Tcprs, which may lead to the development of a new generation of cell therapies.

Beta2-Microglobulin as Predictive Biomarkers in the Prognosis of Hepatocellular Carcinoma and Development of a New Nomogram

Background

Accurate prognosis is crucial for improving hepatocellular carcinoma (HCC) patients, clinical management, and outcomes post-liver resection. However, the lack of reliable prognostic indicators poses a significant challenge. This study aimed to develop a user-friendly nomogram to predict HCC patients' post-resection prognosis.

Methods

We retrospectively analyzed the data from 1091 HCC patients, randomly split into training (n=767) and validation (n=324) cohorts. Receiver operating characteristic (ROC) curves determined the optimal cut-off value for alpha1-microglobulin (α1MG) and Beta2-microglobulin (β2MG). Kaplan-Meier analysis assessed microglobulin's impact on survival, followed by Cox regression to identify prognostic factors and construct a nomogram. The predictive accuracy and discriminative ability of the nomogram were measured by the concordance index (C-index), calibration curves, area under the ROC curve (AUC), and decision curve analysis (DCA), and were compared with the BCLC staging system, Edmondson grade, or BCLC stage plus Edmondson grade.

Results

Patients with high β2MG (≥2.395mg/L) had worse overall survival (OS). The nomogram integrated β2MG, BCLC stage, Edmondson grade, microvascular invasion (MVI), and serum carbohydrate antigen 199 (CA199) levels. C-index for training and validation cohorts (0.712 and 0.709) outperformed the BCLC stage (0.660 and 0.657), Edmondson grade (0.579 and 0.564), and the combination of BCLC stage with Edmondson grade (0.681 and 0.668), improving prognosis prediction. Calibration curves demonstrated good agreement between predicted and observed survival. AUC values exceeded 0.700 over time, highlighting the nomogram's discriminative ability. DCA revealed superior overall net income compared to other systems, emphasizing its clinical utility.

Conclusion

Our β2MG-based nomogram accurately predicts HCC patients' post-resection prognosis, aiding intervention and follow-up planning. Significantly, our nomogram surpasses existing prognostic indicators, including BCLC stage, Edmondson grade, and the combination of BCLC stage with Edmondson grade, by demonstrating superior predictive performance.

β2-microglobulin and colorectal cancer among inpatients: a case-control study

Β2-microglobulin (β2-M) is associated with various malignancies. However, the relationship between β2-M and colorectal cancer (CRC) remains unclear. We explored the association between β2-M and CRC among inpatients who underwent colonoscopy and explored factors that may modify the association. All consecutive inpatients who underwent colonoscopy were enrolled in a tertiary hospital between April 2015 and June 2022. Inpatients with initial CRC or normal colonoscopies were considered eligible as cases or controls, respectively. Baseline characteristics and laboratory indicators of the participants were collected from electronic medical records. Logistic regression analysis, smooth curve fitting, sensitivity analysis, and subgroup analysis were conducted in the present study. After adjusting for baseline clinical characteristics and laboratory parameters, β2-M was positively associated with CRC (odds ratio [OR] 1.32; 95% confidence interval [CI] 1.11-1.58) among inpatients. When the β2-M level was assigned as tertiles, participants in the highest tertile presented with a higher risk of CRC (OR 2.33; 95% CI 1.57-3.48). A positive linear association was observed between β2-M and CRC with smooth curve fitting. In particular, it may be of great importance to monitor β2-M levels for predicting CRC patients.

Analysis of the B2M Expression in Colon Adenocarcinoma and Its Correlation with Patient Prognosis

Colon adenocarcinoma (COAD) is one of the most common malignant tumors in clinics. It is often found at an advanced stage, with high incidence and poor prognosis; early diagnosis is difficult and treatment methods are limited. In order to find new methods for diagnosis and treatment of COAD, people pay more and more attention to the discovery and functional research of new oncogenes and tumor suppressor genes of COAD. β2-microglobulin (B2M) plays different physiological and pathological roles in tumor cells and nontumor cells. At present, there is no public report on the expression of B2M in COAD. In this study, the expression of B2M mRNA in COAD tissues was compared with that in normal tissues. The relationship between the expression of B2M mRNA and the stage, histological subtype, lymph node metastasis, TP53 mutation, and survival time of COAD was discussed. It was found that B2M is a potential tumor suppressor gene in COAD. The decreased expression of B2M after mutation can cause immune escape of COAD cells, thus affecting the therapeutic effect and prognosis. This study provides a new idea for the prevention and treatment of COAD.

Lifting the Veil: Characteristics, Clinical Significance, and Application of β-2-Microglobulin as Biomarkers and Its Detection with Biosensors

Because β-2-microglobulin (β₂M) is a surface protein that is present on most nucleated cells, it plays a key role in the human immune system and the kidney glomeruli to regulate homeostasis. The primary clinical significance of β₂M is in dialysis-related amyloidosis, a complication of end-stage renal disease caused by a gradual accumulation of β₂M in the blood. Therefore, the function of β₂M in kidney-related diseases has been extensively studied to evaluate its glomerular and tubular functions. Because increased β₂M shedding due to rapid cell turnover may indicate other underlying medical conditions, the possibility to use β₂M as a versatile biomarker rose in prominence across multiple disciplines for various applications. Therefore, this work has reviewed the recent use of β₂M to detect various diseases and its progress as a biomarker. While the use of state-of-the-art β₂M detection requires sophisticated tools, high maintenance, and labor cost, this work also has reported the use of biosensor to quantify β₂M over the past decade. It is hoped that a portable and highly efficient β₂M biosensor device will soon be incorporated in point-of-care testing to provide safe, rapid, and reliable test results.

Can conventional clinical chemistry tests help doctors in the monitoring of oncology patients?

The use of laboratory assays in the diagnostic care of oncology patients can markedly increase the efficacy of cancer treatments. Many cancer-specific biomarker assays have been developed. However, the use of these has some limitations due to their cost. Moreover, not every diagnostic laboratory can perform a complete set of these assays. On the other hand, the smart use of conventional clinical chemistry tests could improve the management of cancer. They could be especially valuable tools in the long-term care of patients with a verified diagnosis. In this review, we discuss the utilization of the conventional clinical chemistry assays for the diagnosis, monitoring and prognosis of various oncological diseases. The use of conventional blood tests to assess the levels of chemical elements, metabolites and proteins (including enzymatic activity measurements) in the care of oncology patients is discussed. We have shown that some clinical chemistry assays could be used in the management of distinct kinds of cancer.

B2M overexpression correlates with malignancy and immune signatures in human gliomas

Because of the limited treatment strategy of gliomas, the key of diagnosis and treatment is finding new molecular biomarkers. Here, we explored the potential of β2-microglobulin (B2M) to serve as a hopeful candidate for immunotherapy or diagnostic biomarker in gliomas. The genomic profiles, clinical characteristics, and immune signatures were analyzed based on TCGA and CGGA databases. We carried out the whole statistical analyses using R project. High B2M expression correlated with worse prognosis. Somatic mutations of gliomas with high B2M expression are associated with PTEN deletion and EGFR amplification. Isocitrate dehydrogenase (IDH) mutations accounted for 82% in gliomas with low B2M expression. In addition, B2M positively correlated with ESTIMATE scores, interacted with infiltrating immune and stromal cell types. B2M also suppressed anti-tumor immunity through immune related processes. Meanwhile, B2M was associated with immune checkpoint molecules and inflammatory activities. Finally, functional annotation of the identified B2M related genes verified that B2M was a potential candidate for immunotherapy. We confirmed that B2M played a critical role in tumor progression, patient prognosis and immunotherapy of gliomas.

Serum and Saliva Concentrations of Biochemical Parameters in Men with Prostate Cancer and Benign Prostate Hyperplasia

OBJECTIVES

To find suitable biomarkers for diagnosis of prostate cancer (PC) in serum and saliva; also, to evaluate the diagnostic efficacy of saliva in patients with PC.

METHODS

This case-control study included 20 patients with PC and 20 patients with benign prostatic hyperplasia (BPH). Blood and saliva were collected from the participants and centrifuged. Serum and supernatant saliva were used for biochemical analysis. We evaluated serum and salivary levels of urea, creatinine, prostate-specific antigen (PSA), creatine kinase BB (CK-BB), zinc, β-2 microglobulin (B2M), and melatonin. Also, we used Mann-Whitney U testing, Spearman correlation coefficients, and receiver operating characteristic (ROC) analysis to evaluate the data.

RESULTS

Serum and salivary concentrations of urea, creatinine, PSA, CK-BB, zinc, and B2M were significantly higher in patients with PC, compared with the BPH group (P <.05). However, serum and salivary concentrations of melatonin were significantly lower in patients with PC, compared with BPH group (P <.05). In both groups, salivary concentrations of all markers were lower (P <.05), compared with those values in serum. We observed positive correlation between serum and salivary concentrations of all markers studied (P <.05).

CONCLUSION

From the data, we conclude that investigation using saliva specimens is a noninvasive, simple, and effective tool for screening of biochemical parameters.

β2-microglobulin has a different regulatory molecular mechanism between ER+ and ER- breast cancer with HER2. BMC Cancer 2019;19:223. [PMID: 30866857 PMCID: PMC6417228 DOI: 10.1186/s12885-019-5410-1]

Background

Previous studies have demonstrated that β2-microglobulin (β2M) promotes the growth and survival of a variety of cancer cells and has different regulatory effects on the expression of Bcl-2 and HER2 in HER2⁻ breast cancer cells. However, β2M-mediated signaling in ER⁺ and ER⁻ breast cancer with HER2⁻ remains unclear.

Methods

β2M expression vector and siRNA were transfected into two types of HER2⁻ breast cancer cells, and the possible relevant signaling molecules were subsequently analyzed by real-time PCR and western blotting. These signaling molecules were also analyzed by real-time PCR and immunohistochemistry (IHC) in two types of HER2⁻ breast cancer tissues, and the associations between β2M and these signaling molecules were assessed using Spearman’s correlation analysis.

Results

β2M silencing downregulated p-SGK1/SGK1 levels and Bcl-2 expression, and β2M overexpression downregulated p-CREB/CREB and significantly upregulated p-SGK1/SGK1 levels and Bcl-2 expression, and both resulting processes did not affect HER2, HIF-1α, VEGF, and ERK signaling in ER⁺ breast cancer cells with HER2⁻. β2M silencing upregulated p-CREB/CREB and VEGF protein and significantly downregulated p-ERK/ERK levels, and β2M overexpression downregulated p-CREB/CREB and VEGF, significantly upregulated p-ERK/ERK levels, and both resulting processes did not affect HIF-1α and SGK1 signaling in ER⁻ breast cancer cells with HER2⁻. β2M expression was positively correlated with p-CREB, p-SGK1, and Bcl-2 expression and had no correlation with HIF-1α, VEGF, and p-ERK1/2, whereas p-SGK1 exhibited a significantly positive correlation with Bcl-2 expression in cancer tissues of patients with luminal A breast cancer, which coincide with the results obtained from the same molecular types of breast cancer cells except CREB signaling. However, β2M expression did not show a significant correlation with HIF-1α, p-CREB, VEGF, p-SGK1, p-ERK1/2, and Bcl-2 expression in cancer tissues of patients with basal-like breast cancer, which was discordant with the results obtained from the same molecular types of breast cancer cells.

Conclusions

β2M has a different molecular regulatory mechanism between ER⁺ and ER⁻ breast cancer with HER2⁻, and it may promote tumor survival through the SGK1/Bcl-2 signaling pathway in ER⁺ breast cancer with HER2⁻ and has no regulatory effects on ER⁻ breast cancer with HER2⁻.

Beta 2-microglobulin regulates amyloid precursor-like protein 2 expression and the migration of pancreatic cancer cells

Beta 2-microglobulin (β₂m) is a component of the major histocompatibility complex (MHC) class I molecule, which presents tumor antigens to T lymphocytes to trigger cancer cell destruction. Notably, β₂m has been reported as persistently expressed, rather than down regulated, in some tumor types. For renal cell and oral squamous cell carcinomas, β₂m expression has been linked to increased migratory capabilities. The migratory ability of pancreatic cancer cells contributes to their metastatic tendencies and lethal nature. Therefore, in this study, we examined the impact of β₂m on pancreatic cancer cell migration. We found that β₂m protein is amply expressed in several human pancreatic cancer cell lines (S2-013, PANC-1, and MIA PaCa-2). Reducing β₂m expression by short interfering RNA (siRNA) transfection significantly slowed the migration of the PANC-1 and S2-013 cancer cell lines, but increased the migration of the MIA PaCa-2 cell line. The amyloid precursor-like protein 2 (APLP2) has been documented as contributing to pancreatic cancer cell migration, invasiveness, and metastasis. We have previously shown that β₂m/HLA class I/peptide complexes associate with APLP2 in S2-013 cells, and in this study we also detected their association in PANC-1 cells but not MIA PaCa-2 cells. In addition, siRNA down regulation of β₂m expression diminished the expression of APLP2 in S2-013 and PANC-1 but heightened the level of APLP2 in MIA PaCa-2 cells, consistent with our migration data and co-immunoprecipitation data. Thus, our findings indicate that β₂m regulates pancreatic cancer cell migration, and furthermore suggest that APLP2 is an intermediary in this process.

Mesenchymal Stromal Cells-Derived β2-Microglobulin Promotes Epithelial-Mesenchymal Transition of Esophageal Squamous Cell Carcinoma Cells

Mesenchymal stromal cells (MSCs) have been considered as one of the pivotal type of cells composing the tumor microenvironment. Although contact-dependent mechanisms and paracrine factors are thought to collaborate in governing the MSCs-based effects on tumors progression, the underlying mechanisms remain largely unknown. In particular, the involvement of MSCs-derived cytokines in the epithelial-mesenchymal transition (EMT) of esophageal squamous cell carcinoma (ESCC) has not been clarified. In this study, we observed that β2-Microglobulin (B2M) is highly expressed in MSCs but scarcely in ESCC cells. Based on the previously described EMT promoting effect of B2M, we investigated the in vitro effect of MSCs-derived B2M on the EMT of ESCC cells, and discovered its subsequent enhancing effects on cell mobility and tumor-initiation. Further xenograft transplantation experiments confirmed the in vivo induction of tumor-initiation by MSCs-derived B2M. Noteworthy, we showed that the B2M expression positively correlated with poor prognosis. The fact that B2M is primarily expressed by the stroma of the ESCC tissue strengthens our hypothesis that in ESCC, MSCs-derived B2M promotes tumor-initiation and invasion via enhancing EMT, resulting in an adverse prognosis for the patients. Our results will be valuable for the prediction of the development and treatment of ESCC.

The Role of the Lysyl Oxidases in Tissue Repair and Remodeling: A Concise Review

Tissue injury provokes a series of events containing inflammation, new tissue formation and tissue remodeling which are regulated by the spatially and temporally coordinated organization. It is an evolutionarily conserved, multi-cellular, multi-molecular process via complex signalling network. Tissue injury disorders present grievous clinical problems and are likely to increase since they are generally associated with the prevailing diseases such as diabetes, hypertension and obesity. Although these dynamic responses vary not only for the different types of trauma but also for the different organs, a balancing act between the tissue degradation and tissue synthesis is the same. In this process, the degradation of old extracellular matrix (ECM) elements and new ones' synthesis and deposition play an essential role, especially collagens. Lysyl oxidase (LOX) and four lysyl oxidase-like proteins are a group of enzymes capable of catalyzing cross-linking reaction of collagen and elastin, thus initiating the formation of covalent cross-links that insolubilize ECM proteins. In this way, LOX facilitates ECM stabilization through ECM formation, development, maturation and remodeling. This ability determines its potential role in tissue repair and regeneration. In this review, based on the current in vitro, animal and human in vivo studies which have shown the significant role of the LOXs in tissue repair, e.g., tendon regeneration, ligament healing, cutaneous wound healing, and cartilage remodeling, we focused on the role of the LOXs in inflammation phase, proliferation phase, and tissue remodeling phase of the repair process. By summarizing its healing role, we hope to shed light on the understanding of its potential in tissue repair and provide up to date therapeutic strategies towards related injuries.

HOX gene expression predicts response to BCL-2 inhibition in acute myeloid leukemia

Inhibitors of B-cell lymphoma-2 (BCL-2) such as venetoclax (ABT-199) and navitoclax (ABT-263) are clinically explored in several cancer types, including acute myeloid leukemia (AML), to selectively induce apoptosis in cancer cells. To identify robust biomarkers for BCL-2 inhibitor sensitivity, we evaluated the ex vivo sensitivity of fresh leukemic cells from 73 diagnosed and relapsed/refractory AML patients, and then comprehensively assessed whether the responses correlated to specific mutations or gene expression signatures. Compared with samples from healthy donor controls (nonsensitive) and chronic lymphocytic leukemia (CLL) patients (highly sensitive), AML samples exhibited variable responses to BCL-2 inhibition. Strongest CLL-like responses were observed in 15% of the AML patient samples, whereas 32% were resistant, and the remaining exhibited intermediate responses to venetoclax. BCL-2 inhibitor sensitivity was associated with genetic aberrations in chromatin modifiers, WT1 and IDH1/IDH2. A striking selective overexpression of specific HOXA and HOXB gene transcripts were detected in highly BCL-2 inhibitor sensitive samples. Ex vivo responses to venetoclax showed significant inverse correlation to β2-microglobulin expression and to a lesser degree to BCL-XL and BAX expression. As new therapy options for AML are urgently needed, the specific HOX gene expression pattern can potentially be used as a biomarker to identify venetoclax-sensitive AML patients for clinical trials.

Human epithelial-type ovarian tumour marker beta-2-microglobulin is regulated by the TGF-β signaling pathway

Background

Beta-2-microglobulin (B2M), a light chain subunit of the major histocompatibility complex (MHC) class I complex, has been implicated in tumorigenesis. However, whether it is expressed in different epithelial-type ovarian tumours remains unknown. This study was performed to examine the expression of B2M in different histopathological types of ovarian tumours, to explore the function of B2M in ovarian cancer (OC) cells and to investigate the mechanisms underlying the regulation of B2M by the TGF-β signaling pathway.

Methods

B2M expression in normal ovarian tissues and epithelia-type ovarian tumours was detected by immunohistochemistry and Western blot, followed by the analysis of association with clinical features. OC cells were transfected with B2M-siRNA and cell proliferation, migration and invasion were determined by WST-1 assay, wound healing assay and Transwell invasion assay, respectively. The regulation of B2M by the TGF-β signaling pathway in OC cells was examined by Western blot, ELISA and qRT-PCR.

Results

We found that B2M was overexpressed in ovarian borderline and malignant tumours compared with benign tumours and normal controls, but was not associated with age, tumour size, lymph node metastasis and clinical stage. Knocking down of B2M led to a decrease in OC cell proliferation, migration and invasion. The expression of B2M was downregulated by TGF-β1 in OC cells, which was abolished in the presence of the inhibitor of TGF-β type I receptor.

Conclusion

Our findings suggest that B2M is a potential tissue biomarker and therapeutic target of borderline and malignant ovarian tumours and the dysregulation of B2M in these tumours may be mediated by the TGF-β signaling pathway.

The Implication and Significance of Beta 2 Microglobulin: A Conservative Multifunctional Regulator

OBJECTIVE

This review focuses on the current knowledge on the implication and significance of beta 2 microglobulin (β2M), a conservative immune molecule in vertebrate.

DATA SOURCES

The data used in this review were obtained from PubMed up to October 2015. Terms of β2M, immune response, and infection were used in the search.

STUDY SELECTIONS

Articles related to β2M were retrieved and reviewed. Articles focusing on the characteristic and function of β2M were selected. The exclusion criteria of articles were that the studies on β2M-related molecules.

RESULTS

β2M is critical for the immune surveillance and modulation in vertebrate animals. The dysregulation of β2M is associated with multiple diseases, including endogenous and infectious diseases. β2M could directly participate in the development of cancer cells, and the level of β2M is deemed as a prognostic marker for several malignancies. It also involves in forming major histocompatibility complex (MHC class I or MHC I) or like heterodimers, covering from antigen presentation to immune homeostasis.

CONCLUSIONS

Based on the characteristic of β2M, it or its signaling pathway has been targeted as biomedical or therapeutic tools. Moreover, β2M is highly conserved among different species, and overall structures are virtually identical, implying the versatility of β2M on applications.

Circulating Beta-2 Microglobulin and Risk of Cancer: The Atherosclerosis Risk in Communities Study (ARIC)

BACKGROUND

Serum β-2 microglobulin (B2M), a major histocompatibility complex class I molecule that is a biomarker of kidney filtration and increased cell turnover, is elevated at the time of diagnosis in hematological and some solid cancers. However, serum B2M was not examined prospectively as a marker for cancer risk. We hypothesized that in a population without a prior cancer diagnosis, serum B2M is associated with risk of cancer (n = 2,436), including colorectal (n = 255), lung (n = 298), breast (n = 424), and prostate (n = 524) cancers, and hematological (n = 176) malignancies.

METHODS

The analytical cohort (n = 12,300) was followed for incident cancers from 1990 through 2006. B2M (range, 0.9-57.8 mg/L) was measured in stored serum collected in 1990-1992. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals for cancer incidence and mortality in relation to quartiles of B2M.

RESULTS

Adjusting for age, sex, race, center, education, body mass index, smoking, aspirin, and hormone therapy (in women) and comparing highest to lowest B2M quartiles, HRs were 1.25 (1.06-1.47; Ptrend = 0.002) for total cancer risk and 2.21 (1.32-3.70; Ptrend=0.001) for colorectal cancer risk, with similar HRs for colon and rectal cancers. These associations remained after adjustment for an inflammatory biomarker, C-reactive protein, and after excluding the first three years of follow-up. Significant associations were also observed for mortality from total, lung, and hematological cancers.

CONCLUSIONS

These findings provide the first evidence that higher serum B2M is associated with increased colorectal cancer risk.

IMPACT

This study supports B2M as a potential biomarker for colorectal cancer risk. Cancer Epidemiol Biomarkers Prev; 25(4); 657-64. ©2016 AACR.

A cystine-knot miniprotein from tomato fruit inhibits endothelial cell migration and angiogenesis by affecting vascular endothelial growth factor receptor (VEGFR) activation and nitric oxide production

SCOPE

Cystine-knot miniproteins are bioactive molecules with a broad range of potential therapeutic applications. Recently, it was demonstrated that two tomato cystine-knot miniproteins (TCMPs) exhibit in vitro antiangiogenic activity on human umbilical vein cells. The aim of the present study was to investigate the effects of a fruit-specific cystine-knot miniprotein of tomato on in vitro endothelial cell migration and in vivo angiogenesis using a zebrafish model.

METHODS AND RESULTS

The cystine-knot protein purified from tomato fruits using gel filtration LC and RP-HPLC inhibited cell migration when tested at 200 nM using the wound healing assay, and reduced nitric oxide formation probed by 4-amino-5-methylamino-27-difluorofluoscescin diacetate. RT-PCR and Western blot analyses demonstrated that vascular endothelium growth factor A dependent signaling was the target of TCMP bioactivity. Angiogenesis was inhibited in vivo in zebrafish embryos treated with 500 nM TCMP.

CONCLUSION

Our results demonstrate that cystine-knot miniproteins present in mature tomato fruits are endowed with antiangiogenic activity in vitro and in vivo. These molecules may confer beneficial effects to tomato dietary intake, along with lycopene and other antioxidants. Further investigation is warranted to explore the potential of these compounds as model scaffolds for the development of new drugs.

Dickkopf-3 (DKK-3) obstructs VEGFR-2/Akt/mTOR signaling cascade by interacting of β2-microglobulin (β2M) in ovarian tumorigenesis

In this study, we investigated a possible mechanism of β2-microglobulin (β2M) function in cancer metastases in vitro, using a human ovarian carcinoma cell line. β2M, a modulator acts as a cell growth-promoting and cellular signaling factors, was identified as a dickkopf-3 (DKK-3) interacting protein. We also observed that DKK-3 suppresses endothelial cell angiogenesis of β2M through vascular endothelial growth factor receptor-2 (VEGFR-2) in tumorigenesis. Luciferase activity was remarkably reduced by the transfection of DKK-3 in a dose-dependent manner. In addition, over-expression of β2M activates cell growth by suppressing DKK-3-induced apoptosis. The effect of β2M on cell cycle and apoptosis-regulatory components was also confirmed through the silencing of β2M expression. Furthermore, induction of β2M-mediated VEGFR-2/Akt/mTOR phosphorylation and tumor angiogenesis was significantly suppressed by over-expression of DKK-3. Taken together, our results suggest an underlying mechanism for an increase of β2M-related activity in ovarian tumor cells.

RANK-mediated signaling network and cancer metastasis

Cancer metastasis is highly inefficient and complex. Common features of metastatic cancer cells have been observed using cancer cell lines and genetically reconstituted mouse and human tumor xenograft models. These include cancer cell interaction with the tumor microenvironment and the ability of cancer cells to sense extracellular stimuli and adapt to adverse growth conditions. This review summarizes the coordinated response of cancer cells to soluble growth factors, such as RANKL, by a unique feed forward mechanism employing coordinated upregulation of RANKL and c-Met with downregulation of androgen receptor. The RANK-mediated signal network was found to drive epithelial to mesenchymal transition in prostate cancer cells, promote osteomimicry and the ability of prostate cancer cells to assume stem cell and neuroendocrine phenotypes, and confer the ability of prostate cancer cells to home to bone. Prostate cancer cells with activated RANK-mediated signal network were observed to recruit and even transform the non-tumorigenic prostate cancer cells to participate in bone and soft tissue colonization. The coordinated regulation of cancer cell invasion and metastasis by the feed forward mechanism involving RANKL, c-Met, transcription factors, and VEGF-neuropilin could offer new therapeutic opportunities to target prostate cancer bone and soft tissue metastases.

Evidence for the Influence of the Iron Regulatory MHC Class I Molecule HFE on Tumor Progression in Experimental Models and Clinical Populations

Proteins involved in iron regulation are modifiers of cancer risk and progression. Of these, the HFE protein (high iron gene and its protein product) is of particular interest because of its interaction with both iron handling and immune function and the high rate of genetic polymorphisms resulting in a mutant protein. Clinical studies suggest that HFE polymorphisms increase the risk of certain cancers, but the inconsistent outcomes suggest a more nuanced effect, possibly interacting with other genetic or environmental factors. Some basic science research has been conducted to begin to understand the implications of variant HFE genotype on cancer, but the story is far from complete. In particular, putative mechanisms exist for HFE to affect tumor progression through its role in iron handling and its major histocompatibility complex class I structural features. In this review, the current understanding of the role of HFE in cancer is described and models for future directions are identified.

Antigenic Hsp70-peptide upregulate altered cell surface MHC class I expression in TAMs and increases anti-tumor function in Dalton's lymphoma bearing mice

Major histocompatibility complex (MHC) class I molecules not only provide a mechanistic framework for the cell-to-cell communication, but also possess broader biological function. Due to their ability to regulate presentation of tumor-associated antigens (TAAs), viral peptides which play an essential role in the regulation of immune responses by presenting antigenic peptides to cytotoxic T lymphocytes and by regulating cytolytic activities of immune cells. Tumor cells frequently do not express MHC class I molecules; as a result, tumor cells escape from immune surveillance. Cells surviving in tumor microenvironment are often characterized by a profound immune escape phenotype with alterations in MHC class I way of antigen processing. Cellular components of the tumor microenvironment, in particular alternatively activated M2 phenotype, are involved in tumor progression and suppression of anti-tumor immunity. Hsp70 is well recognized for its role in activating macrophages leading to enhanced production of inflammatory cytokines. It has been observed that Hsp70 derived from normal tissues do not elicit tumor immunity, while Hsp70 preparation from tumor cell associated with antigen are able to elicit tumor immunity. The finding shows that the expression of MHC class I (H2D(b)) drastically decreases in TAMs and Hsp70-peptide complex enhances H2D(b) expression in TAMs and it reverts back the suppressed function of TAMs into the M1 state of immunoregulatory phenotype that promotes tumor regression by enhanced antigen presentation.

miR-154* and miR-379 in the DLK1-DIO3 microRNA mega-cluster regulate epithelial to mesenchymal transition and bone metastasis of prostate cancer

PURPOSE

MicroRNAs in the delta-like 1 homolog-deiodinase, iodothyronine 3 (DLK1-DIO3) cluster have been shown to be critical for embryonic development and epithelial to mesenchymal transition (EMT). DLK1-DIO3 cluster miRNAs are elevated in the serum of patients with metastatic cancer. However, the biologic functions of these miRNAs in the EMT and metastasis of cancer cells are poorly understood. We previously demonstrated the oncogenic and metastatic role of miR-409-3p/5p, a member of this cluster, in prostate cancer. In this study, we defined the role of miR-154* and miR-379, two key members of this cluster, in prostate cancer progression and bone metastasis in both cell line models and clinical specimens.

EXPERIMENTAL DESIGN

Genetic manipulation of miR-154* and miR-379 was performed to determine their role in tumor growth, EMT, and bone metastasis in mouse models. We determined the expression of miR-154* in prostate cancer clinical samples and bone metastasis samples using in situ hybridization and quantum dot labeling.

RESULTS

Elevated expression of miR-154* and miR-379 was observed in bone metastatic prostate cancer cell lines and tissues, and miR-379 expression correlated with progression-free survival of patients with prostate cancer. Intracardiac inoculation (to mimic systemic dissemination) of miR-154* inhibitor-treated bone metastatic ARCaPM prostate cancer cells in mice led to decreased bone metastasis and increased survival.

CONCLUSION

miR-154* and miR-379 play important roles in prostate cancer biology by facilitating tumor growth, EMT, and bone metastasis. This finding has particular translational importance because miRNAs in the DLK1-DIO3 cluster can be attractive biomarkers and possible therapeutic targets to treat bone metastatic prostate cancer.

ATP5b and β2-microglobulin are predictive markers for the prognosis of patients with gallbladder cancer

The differences in clinical, pathological, and biological characteristics between adenocarcinoma (AC) and squamous cell/adenosquamous carcinoma (SC/ASC) of the gallbladder have not been well documented. This study investigates the clinical and pathological associations of ATP5B and β2M with benign and malignant lesions of the gallbladder. In this study, ATP5B and β2M expression in 46 SC/ASCs and 80 ACs were examined using immunohistochemistry. The rate of ATP5B positive expression was significantly lower, while the rate of β2M expression was significantly higher, in AC and SC/ASC than in gallbladder adenomas, gallbladder polyps, or gallbladder epithelium with stone (P < 0.01). More SC/ASCs had larger tumor mass and good differentiation compared to ACs. Positive β2M and negative ATP5B expression were significantly associated with large tumor size, high TNM stage, lymph node metastasis, and invasion of SC/ASCs and ACs. Univariate Kaplan-Meier analysis showed that positive β2M (P < 0.05 or P < 0.001) expression and negative ATP5B (P < 0.001) expression were significantly associated with decreased overall survival in both SC/ASC and AC patients. Multivariate Cox regression analysis showed that negative ATP5B expression is an independent-prognostic factor for poor prognosis in both SC/ASC (P < 0.01) and AC (P < 0.001) patients. Positive β2M expression is an independent-prognostic factor for poor prognosis in AC (P < 0.05) patients. Our study suggested that positive β2M expression or loss of ATP5B expression in tumor tissues is closely related to the metastasis, invasion, and poor-prognosis of gallbladder cancer.

Characterization of β2-microglobulin expression in different types of breast cancer

Background

Βeta-2-microglobulin (β2-M) has been demonstrated as a growth factor and signaling molecule in breast cancer and leukemia. The purpose of the study is to characterize β2-M expression in molecular subtypes of breast cancer, thereby investigating the mechanism of β2-M action in breast cancer.

Methods

β2-M and B-Cell Lymphoma/Leukemia 2 (Bcl-2) transcript expression levels in breast cancer tissue and the corresponding normal tissue were quantified using real-time PCR. The protein expression levels of β2-M, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), tumor protein 53 (p53) and Ki67 were determined by immunohistochemical (IHC) staining. Following silencing of the β2-M by siRNA, the levels of Bcl-2, ER, PR and HER-2 transcripts and the protein expression levels in human breast cancer cells were measured by real-time PCR and western blotting, respectively.

Results

The expression of β2-M transcripts demonstrated no significant differences between the four breast cancer molecular subtypes and no significant correlations with age, clinical stage or lymph node metastasis. β2-M transcript expression demonstrated a positive correlation when compared to Bcl-2 transcript expression (P < 0.05). The β2-M protein expression was significantly higher in breast cancer when compared with benign breast tumors (P < 0.01), and have no significant correlation with age, clinical stage or lymph node metastasis. There was a significant difference demonstrated in β2-M protein expression in the four breast cancer molecular subtypes (P < 0.05), and between the ER⁺ and ER⁻ groups (P < 0.01); however, no significant difference was demonstrated between the HER-2⁺ and HER-2⁻ groups. β2-M protein expression had a negative correlation with ER protein expression (P < 0.01), a positive correlation with p53 protein expression (P < 0.01), and no correlation with Ki67 protein expression. β2-M silencing significantly inhibited Bcl-2 mRNA expression, but did not inhibit ER, PR and HER-2 mRNA expression in MCF-7 cells (ER⁺, PR⁺ and HER-2⁻). In addition, Bcl-2 and HER-2 mRNA expression were significantly up-regulated in MDA-MB-231 cells (ER⁻, PR⁻ and HER-2⁻), which is consistent with the silencing effect seen at the protein level.

Conclusions

β2-M expression demonstrated a significant difference in the four breast cancer molecular subtypes, and may be related to apoptosis regulation in breast cancer.

Induction of integrin α2 in a highly bone metastatic human prostate cancer cell line: roles of RANKL and AR under three-dimensional suspension culture

Background

Prostate cancer (PCa) bone metastasis can be markedly enhanced by increased receptor activator of NF kappa-B ligand (RANKL) expression in PCa cells. Molecular mechanisms that account for the increased predilection of PCa for bone include increased bone turnover, promotion of PCa cell growth and survival in the bone environment, and recruitment of bystander dormant cells to participate in bone metastasis. The current study tests the hypothesis that PCa cells acquire high adhesion to bone matrix proteins, which controls PCa bone colonization, under the RANKL/RANK and AR axes.

Methods

We used a highly bone metastatic RANKL-overexpressing LNCaP PCa cell line, LNCaP^RANKL, as a model to pursue the molecular mechanisms underlying the increased adhesion of PCa cells to collagens. A three-dimensional (3-D) suspension PCa organoid model was developed. The functions of integrin α₂ in cell adhesion and survival were evaluated by flow cytometry and western blot. AR expression and functionality were compared in 2-D monolayer versus 3-D suspension cultures using AR promoter- and PSA promoter-luciferase activity. AR role in cell adhesion was assessed using an adhesion assay.

Results

LNCaP^RANKL cells were shown to adhere tightly to ColI matrix through increased α₂ integrin expression. This increased adhesion, concomitant with activation of the FAK and Akt pathways, was further enhanced by culturing LNCaP^RANKL cells in 3-D suspension. Under the influence of 3-D suspension culture, AR was restored in LNCaP^RANKL cells via downregulation of AP-4 transcription factor, and supported increased α₂ integrin expression and adhesion to ColI.

Conclusion

3-D suspension culture and in vivo PCa tumor growth restore AR through downregulation of AP-4, enhancing integrin α₂ expression and adhesion to ColI which is rich in bone matrices. The interactions of PCa with ColI, mediated by integrin α₂ and AR expression, could be a key molecular event accounting for PCa bone metastasis.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-208) contains supplementary material, which is available to authorized users.

Stromal fibroblast-derived miR-409 promotes epithelial-to-mesenchymal transition and prostate tumorigenesis

Tumor-stromal interaction is a dynamic process that promotes tumor growth and metastasis via cell-cell interaction and extracellular vesicles. Recent studies demonstrate that stromal fibroblast-derived molecular signatures can be used to predict disease progression and drug resistance. To identify the epigenetic role of stromal noncoding RNAs in tumor-stromal interactions in the tumor microenvironment, we performed microRNA profiling of patient cancer-associated prostate stromal fibroblasts isolated by laser capture dissection microscopy and in bone-associated stromal models. We found specific upregulation of miR-409-3p and miR-409-5p located within the embryonically and developmentally regulated DLK1-DIO3 (delta-like 1 homolog-deiodinase, iodothyronine 3) cluster on human chromosome 14. The findings in cell lines were further validated in human prostate cancer tissues. Strikingly, ectopic expression of miR-409 in normal prostate fibroblasts conferred a cancer-associated stroma-like phenotype and led to the release of miR-409 via extracellular vesicles to promote tumor induction and epithelial-to-mesenchymal transition in vitro and in vivo. miR-409 promoted tumorigenesis through repression of tumor suppressor genes such as Ras suppressor 1 and stromal antigen 2. Thus, stromal fibroblasts derived miR-409-induced tumorigenesis, epithelial-to-mesenchymal transition and stemness of the epithelial cancer cells in vivo. Therefore, miR-409 appears to be an attractive therapeutic target to block the vicious cycle of tumor-stromal interactions that plagues prostate cancer patients.

Adenovirus expressing β2-microglobulin recovers HLA class I expression and antitumor immunity by increasing T-cell recognition

Optimal tumor cell surface expression of human leukocyte antigen (HLA) class I molecules is essential for the presentation of tumor-associated peptides to T-lymphocytes. However, a hallmark of many types of tumor is the loss or downregulation of HLA class I expression associated with ineffective tumor antigen presentation to T cells. Frequently, HLA loss can be caused by structural alterations in genes coding for HLA class I complex, including the light chain of the complex, β2-microglobulin (β2m). Its best-characterized function is to interact with HLA heavy chain and stabilize the complex leading to a formation of antigen-binding cleft recognized by T-cell receptor on CD8+ T cells. Our previous study demonstrated that alterations in the β2m gene are frequently associated with cancer immune escape leading to metastatic progression and resistance to immunotherapy. These types of defects require genetic transfer strategies to recover normal expression of HLA genes. Here we characterize a replication-deficient adenoviral vector carrying human β2m gene, which is efficient in recovering proper tumor cell surface HLA class I expression in β2m-negative tumor cells without compromising the antigen presentation machinery. Tumor cells transduced with β2m induced strong activation of T cells in a peptide-specific HLA-restricted manner. Gene therapy using recombinant adenoviral vectors encoding HLA genes increases tumor antigen presentation and represents a powerful tool for modulation of tumor cell immunogenicity by restoration of missing or altered HLA genes. It should be considered as part of cancer treatment in combination with immunotherapy.

miR-409-3p/-5p promotes tumorigenesis, epithelial-to-mesenchymal transition, and bone metastasis of human prostate cancer

PURPOSE

miR-409-3p/-5p is a miRNA expressed by embryonic stem cells, and its role in cancer biology and metastasis is unknown. Our pilot studies demonstrated elevated miR-409-3p/-5p expression in human prostate cancer bone metastatic cell lines; therefore, we defined the biologic impact of manipulation of miR-409-3p/-5p on prostate cancer progression and correlated the levels of its expression with clinical human prostate cancer bone metastatic specimens.

EXPERIMENTAL DESIGN

miRNA profiling of a prostate cancer bone metastatic epithelial-to-mesenchymal transition (EMT) cell line model was performed. A Gleason score human tissue array was probed for validation of specific miRNAs. In addition, genetic manipulation of miR-409-3p/-5p was performed to determine its role in tumor growth, EMT, and bone metastasis in mouse models.

RESULTS

Elevated expression of miR-409-3p/-5p was observed in bone metastatic prostate cancer cell lines and human prostate cancer tissues with higher Gleason scores. Elevated miR-409-3p expression levels correlated with progression-free survival of patients with prostate cancer. Orthotopic delivery of miR-409-3p/-5p in the murine prostate gland induced tumors where the tumors expressed EMT and stemness markers. Intracardiac inoculation (to mimic systemic dissemination) of miR-409-5p inhibitor-treated bone metastatic ARCaPM prostate cancer cells in mice led to decreased bone metastasis and increased survival compared with control vehicle-treated cells.

CONCLUSION

miR-409-3p/-5p plays an important role in prostate cancer biology by facilitating tumor growth, EMT, and bone metastasis. This finding bears particular translational importance as miR-409-3p/-5p appears to be an attractive biomarker and/or possibly a therapeutic target to treat bone metastatic prostate cancer.

β2-Microglobulin-mediated signaling as a target for cancer therapy

β2-microglobulin (β2-m) has become the focus of intense scrutiny since the discovery of its undesirable roles promoting osteomimicry and cancer progression. β2-m is a well-known housekeeping protein that forms complexes with the heavy chain of major histocompatibility complex class I molecules, which are heterodimeric cell surface proteins that present antigenic peptides to cytotoxic T cells. On recognition of foreign peptide antigens on cell surfaces, T cells actively bind and lyse antigen-presenting cancer cells. In addition to its roles in tumor immunity, β2-m has two different functions in cancer cells, either tumor promoting or tumor suppressing, in cancer cell context-dependent manner. Our studies have demonstrated that β2-m is involved extensively in the functional regulation of growth, survival, apoptosis, and even metastasis of cancer cells. We found that β2-m is a soluble growth factor and a pleiotropic signaling molecule which interacts with its receptor, hemochromatosis protein, to modulate epithelial-to-mesenchymal transition (EMT) through iron-responsive pathways. Specific antibodies against β2-m have remarkable tumoricidal activity in cancer, through β2-m action on iron flux, alterations of intracellular reactive oxygen species, DNA damage and repair enzyme activities, β-catenin activation and cadherin switching, and tumor responsiveness to hypoxia. These novel functions of β2-m and β2-m signaling may be common to several solid tumors including human lung, breast, renal, and prostate cancers. Our experimental results could lead to the development of a novel class of antibody-based pharmaceutical agents for cancer growth control. In this review, we briefly summarize the recent data regarding β2-m as a promising new cancer therapeutic target and discuss antagonizing this therapeutic target with antibody therapy for the treatment of localized and disseminated cancers.

Diagnostic and prognostic role of preoperative circulating CA 15-3, CA 125, and beta-2 microglobulin in renal cell carcinoma

CA 15-3, CA 125 and β-2 microglobulin are three common tumor markers currently used for diagnosis, prognosis, assessment of therapeutic response, and/or to evaluate recurrence in breast and ovarian cancer and malignant lymphoproliferative disorders, respectively. In the present prospective study we assessed the role of these three serum proteins as biomarkers for renal cell carcinoma (RCC), as well as any association between tumor marker levels and clinical-pathological parameters. CA 15-3, CA 125, and β-2 microglobulin were preoperatively measured in 332 patients who underwent nephrectomy for RCC. Estimates of cancer-specific survival (CSS) was calculated according to the Kaplan-Meier method. Multivariate analysis was performed to identify the most significant variables for predicting CSS. Preoperatively, 35.2% (n = 117), 9.6% (n = 32) and 30.4% (n = 101) of the patients had abnormal levels of CA 15-3, CA 125 and β-2 microglobulin, respectively. Statistically significant differences resulted between CA 15-3, CA 125 and β-2 microglobulin values and tumor size, Fuhrman grade, presence of lymph node, and visceral metastases. CSS was significantly decreased for patients with high levels of CA 15-3, CA 125, and β-2 microglobulin (P < 0.0001, P < 0.0001, and P = 0.001, resp.). At multivariate analysis only age, the presence of visceral metastases, and high levels of CA 15-3 were independent adverse prognostic factors for CSS.

Monoclonal antibodies directed against chicken β2-microglobulin developed with a synthesized peptide

We developed a panel of monoclonal antibodies (MAb) against chicken β2-microglobulin (chβ2M) by fusions between SP2/0 myeloma cells and spleen cells from mice immunized with a synthesized peptide corresponding to positions 91-119 of the COOH domain of chβ2M. Two of them, 6E7 and 3D1, identified as IgG1/κ, could react with chβ2M protein from avian macrophage HD11 cells and human 293T cells transfected with pcDNA3.1-chβ2M in immunofluorescence assays. Only a 12 kDa protein band of chβ2M could be detected in the HD11 and 293T/chβ2M cell lysates by Western blot analysis. Chicken β2M in serum and plasma could be found in Western blot by MAb 3D1. Moreover, MAb 3D1 also recognized the chβ2M antigen on the cell membranes in flow cytometry. Immunohistochemical staining with these MAbs revealed that chβ2M was present in chicken thymus, spleen, and bursa. These MAbs will be good tools for analyzing the mechanism of the chicken immune system.

The presence of adenosine A2a receptor in thyrocytes and its involvement in Graves' IgG-induced VEGF expression

Goitrogenesis in Graves' disease (GD) has been attributed to anti-TSH receptor antibody stimulation. Recently, a role for adenosine A2a receptor (A2aR) in goiter formation was reported in the thyroglobulin-A2aR transgenic mice. However, it is unclear whether A2aR is expressed in the thyroid and whether it is associated with the pathogenesis of goiter in GD. Here, we confirmed the expression of A2aR in FRTL-5 cells, primary normal human thyrocytes (both sexes were used without regard to sex), and thyroid tissue (both sexes were used without regard to sex) by PCR, Western blotting, immunohistochemistry, and immunofluorescence. After treatments with A2aR-specific agonist 2-p-(2-Carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine or GD IgG, the mRNA and protein levels of vascular endothelial growth factor (VEGF), a growth factor related to goitrogenesis, were evaluated along with upstream signaling pathways. A2aR activation and GD IgG promoted the expression of VEGF in thyrocytes, which was accompanied by the activation of cAMP/protein kinase A/phosphorylated-cAMP-response element-binding protein, peroxisome proliferator-activated receptor γ coactivator-1α, and hypoxia-inducible factor-1α. The changes induced by GD IgG were partially abrogated by A2aR small interfering RNA and an A2aR antagonist. These results were supported by data on the goiter samples from the thyrotropin receptor adenovirus-induced GD mouse model (female). These data demonstrate that GD IgG could up-regulate the VEGF expression through A2aR, indicating a potential mechanism for goitrogenesis in GD.

Decipher β2-microglobulin: gain- or loss-of-function (a mini-review)

β2-microglobulin (β2M) functions as a chaperon to maintain structural stability of MHC class I complex that is associated with antigen presentation to cytotoxic (CD8+) T lymphocytes. Cancerous cells in β2M loss-of-function are thought to avoid immune surveillance. As increased level of β2M present in tissue/serum is significantly associated with tumor status in various cancers, β2M may become an important prognostic and survival factor in a range of malignancies. It is believed that β2M acts as hormone-like molecule to trigger a pleiotropic signaling via a ligand-to-receptor binding mechanism. Anti- β2M monoclonal antibodies successfully induce apoptosis in malignant cells, suggesting a surprising therapeutic approach. Of note, β2M is largely localized in the cytoplasm of advanced oral cavity squamous cell carcinoma (OCSCC), in contrast to that in the plasma membrane of normal oral mucosa. This suggests that β2M-derived intracellular signaling might be preceded by its accumulation in the cytoplasm of epithelial cells of tumors. Hence, translocation of β2M from cell surface to cytoplasm in advanced tumors may shed light on the mechanism of β2M-mediated tumorigenesis.

MicroRNA-185 and 342 inhibit tumorigenicity and induce apoptosis through blockade of the SREBP metabolic pathway in prostate cancer cells

MicroRNA (miRNA or miR) inhibition of oncogenic related pathways has been shown to be a promising therapeutic approach for cancer. Aberrant lipid and cholesterol metabolism is involved in prostate cancer development and progression to end-stage disease. We recently demonstrated that a key transcription factor for lipogenesis, sterol regulatory element-binding protein-1 (SREBP-1), induced fatty acid and lipid accumulation and androgen receptor (AR) transcriptional activity, and also promoted prostate cancer cell growth and castration resistance. SREBP-1 was overexpressed in human prostate cancer and castration-resistant patient specimens. These experimental and clinical results indicate that SREBP-1 is a potential oncogenic transcription factor in prostate cancer. In this study, we identified two miRNAs, miR-185 and 342, that control lipogenesis and cholesterogenesis in prostate cancer cells by inhibiting SREBP-1 and 2 expression and down-regulating their targeted genes, including fatty acid synthase (FASN) and 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). Both miR-185 and 342 inhibited tumorigenicity, cell growth, migration and invasion in prostate cancer cell culture and xenograft models coincident with their blockade of lipogenesis and cholesterogenesis. Intrinsic miR-185 and 342 expression was significantly decreased in prostate cancer cells compared to non-cancerous epithelial cells. Restoration of miR-185 and 342 led to caspase-dependent apoptotic death in prostate cancer cells. The newly identified miRNAs, miR-185 and 342, represent a novel targeting mechanism for prostate cancer therapy.

Powerful inhibition of in-vivo growth of experimental hepatic cancers by bombesin/gastrin-releasing peptide antagonist RC-3940-II

Hepatic carcinoma is a major health problem worldwide. Its incidence is increasing in Western countries and there is currently no effective systemic therapy against it. Targeted treatment modalities developed in the past few years have provided very limited success. Development of new treatment strategies is therefore essential. We investigated the effects of bombesin/gastrin-releasing peptide (BN/GRP) antagonist RC-3940-II on experimental human liver cancers in nude mice. SK-Hep-1 and Hep-G2 cancers transplanted subcutaneously into nude mice were treated daily with 10 or 20 µg of RC-3940-II. Tumor growth was monitored for 50-184 days in five experiments. Tumor gene expression was analyzed with PCR array and protein expression by immunoblotting. Characteristics of BN/GRP receptors in the tumors were analyzed by binding assays. Effects of RC-3940-II on cell proliferation were investigated in vitro. RC-3940-II inhibited the growth of SK-Hep-1 cancers in nude mice by 65-98%, with total regression in 9 of 36 tumors in three experiments. The BN/GRP antagonist inhibited the growth of Hep-G2 cancers as well by 73-82% in two experiments, being effective even on originally large tumors. Gene expression analysis showed an increase in several angiogenesis inhibitors and decrease in proangiogenic genes after RC-3940-II treatment. Receptor assays demonstrated high-affinity binding sites for BN/GRP in both tumor lines. BN/GRP antagonist RC-3940-II powerfully inhibits growth of SK-Hep-1 and Hep-G2 cancers in nude mice. Its effect may be linked to changes in expression of those cancer genes important in angiogenesis, invasion, and metastasis. RC-3940-II may be considered for further investigations in treatment of liver cancers.

Prognostic impact of β-2-microglobulin expression in colorectal cancers stratified by mismatch repair status

Background

β-2-microglobulin (B2M) is essential for antigen presentation, yet may also possess proto-oncogenic properties.

Aim

To determine the prognostic impact of B2M in patients with mismatch repair (MMR) proficient and deficient colorectal cancer (CRC) and to investigate whether this effect on outcome is dependent on the local immune response.

Methods

B2M protein expression and tumour-infiltrating immune cells (CD3, CD16, CD163, CD20, CD4, CD45RO, CD56, CD68, CD8, FoxP3, GranzymeB, iNOS, mast cell tryptase, MUM1, PD1, TIA-1) were evaluated in a well characterised tissue microarray of 408 CRCs. The predictive value for clinicopathological features and the prognostic significance of B2M expression were analysed, stratified by MMR status and the immunohistological characteristics of immune cell infiltrates.

Results

Interobserver agreement for B2M staining was high (intra-class correlation coefficient=0.91). Complete B2M loss was more frequent in MMR-deficient (19.4%) compared to MMR-proficient (7.1%) tumours (p<0.001). In MMR-deficient cases, B2M loss predicted rare local recurrence (p=0.034), infrequent nodal-positivity (p=0.035), absence of distant metastasis (p=0.048; sensitivity=100%) and a trend towards favourable survival (p=0.124) independent of immune infiltrates. No associations between B2M and clinicopathological features were observed in MMR-proficient cases.

Conclusions

Our data show for the first time that absence of B2M protein expression identifies MMR-deficient cancers with a favourable clinical course and absence of metastatic disease. Validation of B2M protein expression for sub-classification of MMR-deficient CRC is recommended for future clinical trials.

Upregulation of β2-microglobulin expression in progressive human oral squamous cell carcinoma

The aim of the present study was to investigate β2-microglobulin (β2-M) expression in normal oral mucosa and progressive oral squamous cell carcinoma (OSCC) and to assess the clinical significance of β2-microglobulin expression. The study included 10 cases of normal oral mucosa epithelium specimens, 55 cases of primary OSCC specimens, and 25 cases of OSCC metastasis specimens. Immunohistochemistry was used to determine β2-M expression, and its correlation with clinicopathological factors in progressive OSCC was evaluated. Immunohistochemistry showed that strong β2-M expression was significantly asscociated with tumor size (T3, T4 vs. T1, T2; P=0.001), positive node status (N positive vs. N negative; P=0.000) and advanced clinical stage (III, IV vs. I, II, P=0.000) in primary OSCC lesions. Compared to primary OSCC lesions, the frequency of β2-M expression was significantly increased in metastatic OSCC lesions (P=0.02). In addition, in vitro results from Western blotting showed increased β2-M expression in the two OSCC lines studied. Therefore, we speculate that the up-regulation of β2-M expression may contribute to the oncogenesis of human oral mucosa, tumor invasion and metastasis.

Activation of androgen receptor, lipogenesis, and oxidative stress converged by SREBP-1 is responsible for regulating growth and progression of prostate cancer cells

We previously reported that sterol regulatory element-binding protein-1 (SREBP-1) is involved in the transcriptional regulation of androgen receptor (AR) and formation of fatty acid through altered expression of fatty acid synthase (FASN). In this article, we provide a new finding that SREBP-1 induced oxidative stress in prostate cancer cells through increased production of reactive oxygen species (ROS) and expression of NADPH oxidase 5 (Nox5). We have shown that (i) expression of SREBP-1 protein is positively associated with the clinical Gleason grades in human prostate cancer; (ii) genetic overexpression or knockdown of SREBP-1 in prostate cancer cells resulted in corresponding increased or decreased AR, FASN and Nox5 expression, fatty acid and lipid droplet accumulation, and ROS generation; and (iii) SREBP-1 induces and promotes the growth, migration, invasion, and castration-resistant progression of prostate cancer cells in vitro and in vivo. Our data show a novel molecular mechanism by which SREBP-1 promotes prostate cancer growth and progression through alterations in the concerted intracellular metabolic and signaling networks involving AR, lipogenesis, and ROS in prostate cancer cells.

β2-microglobulin induces epithelial to mesenchymal transition and confers cancer lethality and bone metastasis in human cancer cells

Bone metastasis is one of the predominant causes of cancer lethality. This study demonstrates for the first time how β2-microglobulin (β2-M) supports lethal metastasis in vivo in human prostate, breast, lung, and renal cancer cells. β2-M mediates this process by activating epithelial to mesenchymal transition (EMT) to promote lethal bone and soft tissue metastases in host mice. β2-M interacts with its receptor, hemochromatosis (HFE) protein, to modulate iron responsive pathways in cancer cells. Inhibition of either β2-M or HFE results in reversion of EMT. These results demonstrate the role of β2-M in cancer metastasis and lethality. Thus, β2-M and its downstream signaling pathways are promising prognostic markers of cancer metastases and novel therapeutic targets for cancer therapy.

Inhibition of ADAM9 expression induces epithelial phenotypic alterations and sensitizes human prostate cancer cells to radiation and chemotherapy

INTRODUCTION

Recent studies demonstrated the importance of ADAM9 in prostate cancer relapse upon therapy. In this study, we determined the role of ADAM9 in the therapeutic resistance to radiation and chemotherapy.

MATERIALS AND METHODS

ADAM9 was either transiently or stably knocked down in C4-2 prostate cancer cells. The sensitivity of ADAM9 knockdown cells toward radiation and chemotherapeutic agents were determined. Additionally, the effects of ADAM9 knockdown on prostate cancer cell morphology, biochemical and functional alterations were accessed.

RESULTS

Both transient and stable knockdown of ADAM9 resulted in increased apoptosis and increased sensitivity to radiation. ADAM9 knockdown also increased prostate cancer sensitivity to several chemotherapeutic drugs. ADAM9 knockdown resulted in increased E-cadherin and altered integrin expression and underwent phenotypic epithelial transition. These were reflected by the morphological, biochemical, and functional alterations in the ADAM9 knockdown cells.

CONCLUSIONS

ADAM9 plays a crucial role in prostate cancer progression and therapeutic resistance in part by altering E-cadherin and integrin expression. ADAM9 is an important target for the consideration of treating prostate cancer patients who developed therapeutic resistance and disease relapse.

HLA class I molecules partner with integrin β4 to stimulate endothelial cell proliferation and migration

Among transplant recipients, those who produce antibodies against the donor's human leukocyte antigens (HLAs) are at higher risk for antibody-mediated rejection and transplant vasculopathy, which is a progressive, vasculo-occlusive disease that results in ischemic injury and deterioration of organ function. Antibodies against HLA class I (HLA-I) molecules are thought to contribute to transplant vasculopathy by triggering signals that elicit the activation and proliferation of endothelial cells. Here, we demonstrate a molecular association between HLA-I and the integrin β(4) subunit after the stimulation of endothelial cells with HLA-I-specific antibodies. Knockdown of integrin β(4) in these cells abrogated the ability of HLA-I to stimulate the phosphorylation of the kinases Akt, extracellular signal-regulated kinase (ERK), and Src, as well as cellular proliferation. Similarly, reducing the abundance of HLA-I suppressed integrin β(4)-mediated phosphorylation of ERK and the migration of endothelial cells on laminin-5, a component of the extracellular matrix. These results indicate a mutual dependency between HLA-I and the integrin β(4) subunit to stimulate the proliferation and migration of endothelial cells, which may be important in promoting transplant vasculopathy and tumor angiogenesis.

Beta-2-microglobulin expression correlates with high-grade prostate cancer and specific defects in androgen signaling

BACKGROUND

Previously, we identified Beta-2-microglobulin (beta2M) as an androgen-regulated secreted protein elevated in the serum of prostate cancer patients. In this study, we explore an interaction between beta2M expression, prostate cancer tissue, and the androgen signaling axis.

METHODS

beta2M expression in relation to clinical and pathologic variables was examined in a tissue microarray representing specimens obtained at the time of radical prostatectomy. Viral vectors were designed to down-regulate beta2M expression, and the effects on androgen-dependent growth, transcriptional regulation, and androgen receptor recruitment was investigated in human prostate cancer cell lines.

RESULTS

Variation in beta2M expression in human prostate cancer is associated with characteristics of clinically aggressive disease such as high tumor grade. Knockdown of beta2M expression in human prostate cancer cells resulted in selective defects in androgen-dependent events including growth, gene regulation, and chromatin assembly.

CONCLUSIONS

beta2M expression may provide prognostic information in patients treated with surgery for prostate cancer. Targeting beta2M expression or activity may represent a new and important mechanism to manipulate the androgen signaling axis in patients with prostate cancer.

Killing tumor cells through their surface beta(2)-microglobulin or major histocompatibility complex class I molecules

Targeted antibody-based therapy has been used successfully to treat cancers. Recent studies have demonstrated that tumor cells treated with antibodies specific for beta(2)-microglobulin (beta(2)M) or major histocompatibility complex (MHC) class I molecules undergo apoptosis in vitro and in vivo (mouse models). Antibodies against beta(2)M or MHC class I induce tumor cell apoptosis by 1) recruiting MHC class I molecules to lipid rafts and activating LYN kinase and the signal-transducing enzyme phospholipase C-gamma2-dependent c-Jun N-terminal kinase signaling pathway and 2) expelling interleukin 6 and insulin-like growth factor 1 receptors out of lipid rafts and inhibiting the growth and survival factor-induced activation of the phosphatidylinositol 3-kinase/Akt and extracellular signal-related kinase pathways. Consequently, mitochondrial integrity is compromised, and the caspase-9-dependent cascade is activated in treated tumor cells. However, although beta(2)M and MHC class I are expressed on normal hematopoietic cells, which is a potential safety concern, the monoclonal antibodies were selective to tumor cells and did not damage normal cells in vitro or in human-like mouse models. These findings suggest that targeting beta(2)M or MHC class I by using antibodies or other agents offers a potential therapeutic approach for beta(2)M/MHC class I-expressing malignancies. Cancer 2010. (c) 2010 American Cancer Society.

Validation of endogenous controls for gene expression studies in peripheral lymphocytes from war veterans with and without PTSD

BACKGROUND

Selection of appropriate endogenous control is a critical step in gene expression analysis. The aim of this study was to evaluate expression stability of four frequently used endogenous controls: beta-actin, glyceraldehyde-3-phosphate dehydrogenase, beta2-microglobulin and RNA polymerase II polypeptide A in peripheral blood mononuclear cells from war veterans with and without posttraumatic stress disorder (PTSD). The study was designed as to identify suitable reference gene(s) for normalization of gene expression in peripheral blood mononuclear cells in response to war trauma and/or PTSD.

RESULTS

The variability in expression of the four endogenous controls was assessed by TaqMan Real-time RT-PCR in peripheral blood mononuclear cells from: war veterans with current PTSD, those with lifetime PTSD, trauma controls and healthy subjects. Expression stability was analyzed by GeNorm and NormFinder software packages, and by direct comparison of Ct values. Both, GeNorm and NormFinder identified beta-actin and glyceraldehyde-3-phosphate dehydrogenase as a pair of genes with the lowest stability value.

CONCLUSIONS

The combination of beta-actin and glyceraldehyde-3-phosphate dehydrogenase appeared to be the most suitable reference for studying alterations in gene expression in peripheral blood mononuclear cells related to vulnerability and resilience to PTSD, as well as to trauma-provoked developing of this disorder and recovery from it. Using glyceraldehyde-3-phosphate dehydrogenase, beta-actin and beta2-microglobulin as individual endogenous controls would provide satisfactory data, while RNA polymerase II polypeptide A could not be recommended.

Androgen receptor survival signaling is blocked by anti-beta2-microglobulin monoclonal antibody via a MAPK/lipogenic pathway in human prostate cancer cells

A new cis-acting element, sterol regulatory element-binding protein-1 (SREBP-1) binding site, within the 5'-flanking human androgen receptor (AR) promoter region and its binding transcription factor, SREBP-1, was identified to regulate AR transcription in AR-positive human prostate cancer cells. We further characterized the molecular mechanism by which a novel anti-beta2-microglobulin monoclonal antibody (beta2M mAb), shown to induce massive cell death in a number of human and mouse cancer cell lines, interrupted multiple cell signaling pathways in human prostate cancer cells. beta2M mAb decreased AR expression through inactivation of MAPK and SREBP-1. By inactivation of MAPK, beta2M mAb decreased prostate cancer cell proliferation and survival. By inhibition of SREBP-1, beta2M mAb reduced fatty acid and lipid levels, an integral component of cell membrane, cell signaling mediators, and energy metabolism. These results provide for the first time a molecular link between the beta2M intracellular signaling axis mediated by MAPK and SREBP-1 and involving lipid signaling, which collectively regulates AR expression and function. Antagonizing beta2M by beta2M mAb may be an effective therapeutic approach simultaneously targeting multiple downstream signaling pathways converging with MAPK, SREBP-1, and AR, important for controlling prostate cancer cell growth, survival, and progression.