Midkine positively regulates the proliferation of human gastric cancer cells

Identification of a 9-gene signature to enhance biochemical recurrence prediction in primary prostate cancer: A benchmarking study using ten machine learning methods and twelve patient cohorts

Prostate cancer (PCa) is a prevalent malignancy among men worldwide, and biochemical recurrence (BCR) after radical prostatectomy (RP) is a critical turning point commonly used to guide the development of treatment strategies for primary PCa. However, the clinical parameters currently in use are inadequate for precise risk stratification and informing treatment choice. To address this issue, we conducted a study that collected transcriptomic data and clinical information from 1662 primary PCa patients across 12 multicenter cohorts globally. We leveraged 101 algorithm combinations that consisted of 10 machine learning methods to develop and validate a 9-gene signature, named BCR SCR, for predicting the risk of BCR after RP. Our results demonstrated that BCR SCR generally outperformed 102 published prognostic signatures. We further established the clinical significance of these nine genes in PCa progression at the protein level through immunohistochemistry on Tissue Microarray (TMA). Moreover, our data showed that patients with higher BCR SCR tended to have higher rates of BCR and distant metastasis after radical radiotherapy. Through drug target prediction analysis, we identified nine potential therapeutic agents for patients with high BCR SCR. In conclusion, the newly developed BCR SCR has significant translational potential in accurately stratifying the risk of patients who undergo RP, monitoring treatment courses, and developing new therapies for the disease.

Identification of MDK as a Hypoxia- and Epithelial-Mesenchymal Transition-Related Gene Biomarker of Glioblastoma Based on a Novel Risk Model and In Vitro Experiments

BACKGROUND

Tumor cells are commonly exposed to a hypoxic environment, which can easily induce the epithelial-mesenchymal transition (EMT) of tumor cells, further affecting tumor proliferation, invasion, metastasis, and drug resistance. However, the predictive role of hypoxia and EMT-related genes in glioblastoma (GBM) has not been investigated.

METHODS

Intersection genes were identified by weighted correlation network analysis (WGCNA) and differential expression analyses, and a risk model was further constructed by LASSO and Cox analyses. Clinical, immune infiltration, tumor mutation, drug treatment, and enrichment profiles were analyzed based on the risk model. The expression level of the MDK gene was tested using RT-PCR, immunohistochemistry, and immunofluorescence. CCK8 and EdU were employed to determine the GBM cells' capacity for proliferation while the migration and invasion ability were detected by a wound healing assay and transwell assay, respectively.

RESULTS

Based on the GBM data of the TCGA and GTEx databases, 58 intersection genes were identified, and a risk model was constructed. The model was verified in the CGGA cohort, and its accuracy was confirmed by the ROC curve (AUC = 0.807). After combining clinical subgroups, univariate and multivariate Cox regression analyses showed that risk score and age were independent risk factors for GBM patients. Furthermore, our subsequent analysis of immune infiltration, tumor mutation, and drug treatment showed that risk score and high- and low-risk groups were associated with multiple immune cells, mutated genes, and drugs. Enrichment analysis indicated that the differences between high- and low-risk groups were manifested in tumor-related pathways, including the PI3K-AKT and JAK-STAT pathways. Finally, in vivo experiments proved that the hypoxia environment promoted the expression of MDK, and MDK knockdown reduced the proliferation, migration, and EMT of GBM cells induced by hypoxia.

CONCLUSIONS

Our novel prognostic correlation model provided more potential treatment strategies for GBM patients.

Single-cell RNA sequencing integrated with bulk RNA sequencing analysis reveals diagnostic and prognostic signatures and immunoinfiltration in gastric cancer

BACKGROUND

Early diagnosis and prognostic predication of gastric cancer (GC) pose significant challenges in current clinical practice of GC treatments. Therefore, our aim was to explore relevant gene signatures that can predict the prognosis of GC patients.

METHODS

Here, we established a single-cell transcriptional atlas of GC, focusing on the expression of T-cell-related genes for cell-cell communication analysis, trajectory analysis, and transcription factor regulatory network analysis. Additionally, we conducted validation and prediction of immune-related prognostic gene signatures in GC patients using TCGA and GEO data. Based on these prognostic gene signatures, we predicted the immune infiltration status of GC patients by grouping the patient samples into high or low-risk groups.

RESULTS

Based on 10 tumor samples and corresponding normal samples from GC patients, we selected 18,416 cells for subsequent analysis using single-cell sequencing. From these, we identified 3,284 T-cells and obtained 641 differentially expressed genes related to T-cells from 5 different T-cell subtypes. By integrating bulk RNA sequencing data, we identified prognostic signatures associated with T-cells. Stratifying patients based on these prognostic signatures into high-risk or low-risk groups allowed us to effectively predict their survival rates and the immunoinfiltration status of the tumor microenvironment.

CONCLUSION

This study explored prognostic gene signatures associated with T-cells in GC patients, providing insights into predicting patients' survival rates and immunoinfiltration levels.

Association Between Serum Midkine Level and Gastric Precancerous Lesion in Patients with Gastritis

Background

Gastric cancer is the fifth most common malignancy and the third highest cancer-related mortality worldwide after lung and colorectal cancers. The gastric carcinogenesis is started with precancerous lesion. Prompt diagnosis and management of gastric precancerous lesion may prevent disease progression. Midkine is a growth factor associated with various cancers and proposed as a marker for detecting gastric precancerous lesion.

Objective

The aim of the study is to determine the association between serum midkine level and gastric precancerous lesion in patients with gastritis.

Methods

A cross sectional study was conducted at Haji Adam Malik general hospital. Subjects were obtained by consecutive sampling. Inclusion criteria were patients aged 18 years or older, diagnosed with gastritis from gastroscopy and histopathology results, and willing to cooperate in the study. Each subjects underwent interview and endoscopic examination. Serum midkine level was determined using enzyme-linked immunosorbent assay (ELISA) method. Chi square, receiver operating characteristic (ROC) curve, and logistic regression tests were applied.

Results

A total of 160 subjects were enrolled with 29.4% had gastric precancerous lesion. Serum midkine level was associated with gastric premalignant lesion. Cut off point for serum midkine level was 252 pg/mL with area under the curve of 0.816 (p<0.001). It's sensitivity, specificity, and accuracy in diagnosing gastric precancerous lesion were 74.5%, 71.7%, and 72.5%, respectively. Helicobacter pylori infection, high serum midkine level, heavy alcohol drinker, and family history of gastric cancer were risk factors for gastric precancerous lesion.

Conclusion

Serum midkine level is associated with gastric premalignant lesion in patients with gastritis and has good diagnostic values.

CAF-derived midkine promotes EMT and cisplatin resistance by upregulating lncRNA ST7-AS1 in gastric cancer

This study aimed to investigate the role of cancer-associated fibroblast (CAF)-derived midkine (MK) in cisplatin (DDP) resistance. The primary cultures of CAFs and non-cancer fibroblasts (NFs) were isolated and purified. The DDP-resistant gastric cancer (GC) cells were cultured with CAF-conditioned medium. QRT-PCR and Elisa assays were employed to determine MK expression. The expression of ST7-AS1 was measured by qRT-PCR. The impact of CAFs, MK, and ST7-AS1 silencing on DDP resistance was determined by MTT and Annexin V/PI staining assay. Expression of EMT markers and PI3K/AKT was determined by Western blot and qRT-PCR. The role of MK in DDP resistance was confirmed in a xenograft model. Incubation with CAF-conditioned medium increased the IC50 to DDP. Also, incubation with CAF-conditioned medium increased cell viability, reduced cell apoptosis, and promoted EMT in DDP-resistant GC cells, which were all blocked with MK neutralization antibody treatment. MK increased the DDP resistance and upregulated the expression of ST7-AS1 in DDP-resistant GC cells. Additionally, ST7-AS1 knockdown increased the sensitivity to DDP by inhibiting EMT. Moreover, ST7-AS1 knockdown significantly decreased the phosphorylation of PI3K and AKT, and suppressed EMT, which were restored by MK addition. Finally, MK promoted tumor growth and DDP resistance in a mice model bearing the SGC-7901/DDP xenografts. CAF-derived MK promotes EMT-mediated DDP resistance via upregulation of ST7-AS1 and activation of PI3K/AKT pathway.

Midkine noncanonically suppresses AMPK activation through disrupting the LKB1-STRAD-Mo25 complex

Midkine (MDK), a secreted growth factor, regulates signal transduction and cancer progression by interacting with receptors, and it can be internalized into the cytoplasm by endocytosis. However, its intracellular function and signaling regulation remain unclear. Here, we show that intracellular MDK interacts with LKB1 and STRAD to disrupt the LKB1-STRAD-Mo25 complex. Consequently, MDK decreases the activity of LKB1 to dampen both the basal and stress-induced activation of AMPK by glucose starvation or treatment of 2-DG. We also found that MDK accelerates cancer cell proliferation by inhibiting the activation of the LKB1-AMPK axis. In human cancers, compared to other well-known growth factors, MDK expression is most significantly upregulated in cancers, especially in liver, kidney and breast cancers, correlating with clinical outcomes and inversely correlating with phosphorylated AMPK levels. Our study elucidates an inhibitory mechanism for AMPK activation, which is mediated by the intracellular MDK through disrupting the LKB1-STRAD-Mo25 complex.

Advances in targeted therapy mainly based on signal pathways for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial carcinoma of the head and neck region which mainly distributes in southern China and Southeast Asia and has a crucial association with the Epstein-Barr virus. Based on epidemiological data, both incidence and mortality of NPC have significantly declined in recent decades grounded on the improvement of living standard and medical level in an endemic region, in particular, with the clinical use of individualized chemotherapy and intensity-modulated radiotherapy (IMRT) which profoundly contributes to the cure rate of NPC patients. To tackle the challenges including local recurrence and distant metastasis in the current NPC treatment, we discussed the implication of using targeted therapy against critical molecules in various signal pathways, and how they synergize with chemoradiotherapy in the NPC treatment. Combination treatment including targeted therapy and IMRT or concurrent chemoradiotherapy is presumably to be future options, which may reduce radiation or chemotherapy toxicities and open new avenues for the improvement of the expected functional outcome for patients with advanced NPC.

MiR-326 targets MDK to regulate the progression of cardiac hypertrophy through blocking JAK/STAT and MAPK signaling pathways

Cardiac hypertrophy is a heart reaction to the increase of cardiac load, with the characteristics of increased expression of cardiac hypertrophy markers, enhanced protein synthesis, and enlarged cell area. However, molecular mechanisms in cardiac hypertrophy are still poorly substantiated. It has been reported that miRNAs can modulate human diseases, among which miR-326 has been reported as a biological regulator in human cancers, but its role in cardiac hypertrophy is rarely explored. This study focused on the exploration of the potential of miR-326 in cardiac hypertrophy. Our data revealed the downregulation of miR-326 in the TAC-induced hypertrophic mice and the Ang II-induced hypertrophic H9c2 cells. Functionally, miR-326 attenuated the effect of Ang II on cardiac hypertrophy in vitro. In addition, miR-326 negatively regulated JAK/STAT and MAPK signaling pathways. Mechanistically, miR-326 targeted and inhibited MDK to induce JAK/STAT and MAPK pathways. Rescue assays certified that miR-326 attenuated cardiac hypertrophy through targeting MDK and inhibiting JAK/STAT and MAPK signaling pathways. In brief, our study unveiled that miR-326 targets MDK to regulate the progression of cardiac hypertrophy through blocking JAK/STAT and MAPK signaling pathways, indicating that targeting miR-326 as a potential approach for cardiac hypertrophy treatment.

Experimental Models to Define the Genetic Predisposition to Liver Cancer

Hepatocellular carcinoma (HCC) is a frequent human cancer and the most frequent liver tumor. The study of genetic mechanisms of the inherited predisposition to HCC, implicating gene-gene and gene-environment interaction, led to the discovery of multiple gene loci regulating the growth and multiplicity of liver preneoplastic and neoplastic lesions, thus uncovering the action of multiple genes and epistatic interactions in the regulation of the individual susceptibility to HCC. The comparative evaluation of the molecular pathways involved in HCC development in mouse and rat strains differently predisposed to HCC indicates that the genes responsible for HCC susceptibility control the amplification and/or overexpression of c-Myc, the expression of cell cycle regulatory genes, and the activity of Ras/Erk, AKT/mTOR, and of the pro-apoptotic Rassf1A/Nore1A and Dab2IP/Ask1 pathways, the methionine cycle, and DNA repair pathways in mice and rats. Comparative functional genetic studies, in rats and mice differently susceptible to HCC, showed that preneoplastic and neoplastic lesions of resistant mouse and rat strains cluster with human HCC with better prognosis, while the lesions of susceptible mouse and rats cluster with HCC with poorer prognosis, confirming the validity of the studies on the influence of the genetic predisposition to hepatocarinogenesis on HCC prognosis in mouse and rat models. Recently, the hydrodynamic gene transfection in mice provided new opportunities for the recognition of genes implicated in the molecular mechanisms involved in HCC pathogenesis and prognosis. This method appears to be highly promising to further study the genetic background of the predisposition to this cancer.

Pleiotropic Effects of Heparins: From Clinical Applications to Molecular Mechanisms in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a major health problem worldwide and most cases are incurable because of late presentation. It is the most common primary neoplasm of the liver and often arises in the context of a chronic liver disease that impairs coagulation. Portal vein thrombosis (PVT) is a common complication of HCC that is associated with a poor prognosis. Heparin derivatives are widely used in the management of venous thromboembolism (VTE). Among them low molecular weight heparin (LMWH) favorably influences the survival in patients with advanced cancer, including HCC. Due to their pleiotropic function, heparins affect tumorigenesis in many ways and may promote or hamper tumorigenic transformation depending on the cancer type and cancer stage along with their structural properties and concentration. Thus, their application as an antithrombotic along with the conventional therapy regime should be carefully planned to develop the best management strategies. In this review, we first will briefly review clinical applications of heparin derivatives in the management of cancer with a particular focus on HCC. We then summarize the state of knowledge whereby heparin can crosstalk with molecules playing a role in hepatocarcinogenesis. Lastly, we highlight new experimental and clinical research conducted with the aim of moving towards personalized therapy in cancer patients at risk of thromboembolism.

Changes of serum midkine as a dynamic prognostic factor to monitor disease status in papillary thyroid cancer

This study aimed to investigate the value of dynamic changes of midkine (MK) to monitor post-surgical patients with papillary thyroid cancer (PTC) who were managed with I therapies.MK concentration at initial I ablation therapy (MK1) as well as 10 to 12 months thereafter (MK2) was evaluated. And the dynamic changes of thyroglobulin (Tg) were compared (Tg1 and Tg2). Patients with MK influencing co-morbidities and with positive thyroglobulin antibodies were excluded. Concentrations of MK were measured by enzyme-linked immunosorbent assay.There were 241 PTC patients (36 males, 205 females) enrolled, 55 cases had metastases (8 males, 47 females) during their follow-up. Cox regression showed if Tg2 decreased (compared with Tg1), but not to less than 1.0ng/mL under TSH stimulation, the risk of metastases was 12.554 times more than if it could decrease to the optimal level. If Tg2 increased, the risk is 19.461 times higher. As for MK, if MK2 level decreased (compared with MK1), but not to a normal level, the risk of metastases is 3.006. If MK2 level increased, it would be 5.030 likely to had metastases.Our results indicated that MK could potentially be used as a disease monitoring biomarker for PTC, although inferior to Tg.

Exosomal miR-9 inhibits angiogenesis by targeting MDK and regulating PDK/AKT pathway in nasopharyngeal carcinoma

Background

Exosomes are small vesicles containing a wide range of functional proteins, mRNA and miRNA. Exosomal miRNAs from cancer cells play crucial roles in mediating cell-cell communication and tumor-microenvironment cross talk, specifically in enabling metastasis and promoting angiogenesis. We focused on miR-9 that was identified as a tumor suppressor previously in nasopharyngeal carcinoma (NPC) tumorigenesis.

Methods

Differential centrifugation, transmission electron microscopy and nanoparticle tracking analysis were used to isolate and identify exosomes. Quantitative PCR and western blotting analysis were used to detect miR-9, pri-miR-9, CD63, TSG101, MDK, P70S6K P-Ser424 and PDK1 P-Ser241 expression. Laser confocal microscopy was used to trace exosomal miR-9 secreted by NPC cells into HUVECs. The effect of exosomal miR-9 on cell migration and tube formation of HUVECs in vivo and vitro was assessed by using migration assay, tube formation assay and matrigel plug assay, respectively. Bioinformatics analysis and luciferase reporter assay were utilized to confirm the binding of exosomal miR-9 to the 3′untranslated region (3′-UTR) of MDK, while Phosphorylation Array was performed to identify AKT Pathway in HUVECs treated with exosomal miR-9. Furthermore, Immunohistochemistry (IHC) and in situ hybridization (ISH) was used to detected miR-9, CD31 and MDK expression in human NPC tumor samples.

Results

NPC cells transfected with miR-9-overexpressing lentivirus, released miR-9 in exosomes. Exosomal miR-9 directly suppressed its target gene - MDK in endothelial cells. Mechanistic analyses revealed that exosomal miR-9 from NPC cells inhibited endothelial tube formation and migration by targeting MDK and regulating PDK/AKT signaling pathway. Additionally, the level of MDK was upregulated in NPC tumor samples and was positively correlated with microvessel density. Notably, the level of exosomal miR-9 was positively correlated with overall survival, and MDK overexpression was positively associated with poor prognosis in NPC patients, suggesting the clinical relevance and prognostic value of exosomal miR-9 and MDK.

Conclusions

Taken together, our data identify an extracellular anti-angiogenic role for tumor-derived, exosome-associated miR-9 in NPC tumorigenesis and prompt further investigation into exosome-based therapies for cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0814-3) contains supplementary material, which is available to authorized users.

Suppression of midkine gene promotes the antitumoral effect of cisplatin on human gastric cancer cell line AGS in vitro and in vivo via the modulation of Notch signaling pathway

Midkine (MK) is reported to be associated with the clinical stages and distant metastases in gastric cancer, and to positively regulate the proliferation of human gastric cancer cells. However, the possible mechanisms of MK in the development of gastric cancer are still not fully clarified. In this study, the therapeutic effect of MK inhibition in gastric cancer in vivo and in vitro was investigated, by knock-down of MK expression with a small interfering RNA (siRNA). MK was expressed in gastric carcinoma tissues and cancer cells. The cytotoxic effect of cisplatin on AGS cells in vitro was attenuated by recombinant human MK, but was promoted by suppressing MK expression via downregulating the Notch signaling pathway-related proteins (Notch 1, Notch 2, Delta-like 1 and Jagged 1). Suppression of MK expression also promoted the inhibitory effect of cisplatin on AGS cells in vivo. In concusion, suppression of midkine gene promoted the antitumoral effect of cisplatin on human gastric cell line AGS in vitro and in vivo via Notch signaling pathway.

Midkine is up-regulated in both cancerous and inflamed bowel, reflecting lymph node metastasis in colorectal cancer and clinical activity of ulcerative colitis

Midkine is a multifunctional cytokine and growth factor displaying proinflammatory and pro-tumorigenic activity. Its association with bowel diseases has not been fully elucidated. Our purpose was to delineate midkine expression pattern by RT-qPCR in inflamed/cancerous bowel (n=208) and whole blood (n=150) in colorectal cancer (CRC), Crohn's disease (CD), and ulcerative colitis (UC) and to evaluate midkine dynamics in early postoperative period following colorectal surgery. The expression of midkine was significantly up-regulated in stage III CRC and independently associated with lymph node metastasis. The expression of midkine in whole blood was up-regulated solely in N1 CRC. Midkine expression in cancer-free tissue (CRC) was also elevated and dependent on CRC advancement. In IBD, inflammation increased the bowel expression of midkine solely in UC, in a manner proportional to the disease clinical activity. Large and small bowel differed with respect to the expression of midkine in quiescent tissue (higher in small bowel) and to its correlation pattern with chemokines (in a large bowel) and angiogenic factors and cell cycle regulators (in a small bowel). Circulating midkine and its expression in whole blood dropped directly following colorectal surgery; however, the concentration of midkine in serum was restored on postoperative day three. Midkine is involved in bowel inflammation in UC and lymph node metastasis in CRC, rendering midkine an attractive target for their treatment. Owing to midkine elevation in early postoperative period and its overexpression in tumor-adjacent tissue, targeting midkine might be considered also as a prevention of CRC recurrence following curative tumor resection.

Midkine neurite growth-promoting factor 2 expression as a potential prognostic marker of adjuvant therapy in head and neck squamous cell carcinoma

OBJECTIVE

The prognostic function of neurite growth-promoting factor 2 (Midkine (MK)) in adjuvant treatment of head and neck squamous cell carcinoma (HNSCC) is unclear. This study examined whether MK expression may predict treatment response and survival in resectable HNSCC patients.

METHODS

In this retrospective study, MK expression in 144 HNSCC patients was analyzed by immunohistochemistry. A subset of patients (n = 10) had MK expression levels analyzed by western blot and semi-quantitative reverse transcription polymerase chain reaction. Data were analyzed using the Log-rank test and α = 0.05.

RESULTS

Expression of MK was associated with poorer five-year progression-free and overall survival rates in HNSCC patients (p = 0.002).

CONCLUSION

MK might play an important role in the progression of HNSCC and may be a useful prognostic factor.

Midkine is associated with neuroendocrine differentiation in castration-resistant prostate cancer

BACKGROUND

Castration-resistant prostate cancer (CRPC) is an incurable disease and both androgen-deprivation therapy (ADT) and neuroendocrine differentiation (NED) are closely related to CRPC transition. More knowledge concerning neuroendocrine (NE)-transformed PC cells, the NED process and its association with CRPC, is needed. Expression of growth factor midkine (MDK) is correlated with poor clinical outcomes in various human cancers, including PC. In the present study, we have evaluated MDK expression and NED in two separate tumor groups: early and advanced PC.

METHODS

Immunohistochemical analysis of MDK, the neuronal marker tubulin-beta III (TUBB3) and the NE-marker chromogranin A (CGA) in a human archival material consisting of hormone naive (HN)/stage T1b (n = 29) and CRPC (n = 24) tumors. Triple immunofluorescent imaging was performed on a selection of specimens.

RESULTS

MDK, TUBB3, and CGA were upregulated in CRPC compared to HN tumors. MDK was highly associated to the expression of both CGA and TUBB3, and identified MDK-positive NE-like looking cells found to co-express CGA or, more commonly, CGA together with TUBB3. CGA and TUBB3 staining displayed a partial expression overlap, an overlap almost exclusively displaying also MDK expression.

CONCLUSIONS

MDK upregulation in CRPC is associated with NED (shown by its relation to CGA and TUBB3). The results suggest that MDK represents an over-bridging marker between different populations of NE-like tumor cells, possibly as part of the NED process and associated CRPC transition, something that needs to be evaluated experimentally as does the applicability of MDK as a future target.

Deregulation of signalling pathways in prognostic subtypes of hepatocellular carcinoma: novel insights from interspecies comparison

Hepatocellular carcinoma is a frequent and fatal disease. Recent researches on rodent models and human hepatocarcinogenesis contributed to unravel the molecular mechanisms of hepatocellular carcinoma dedifferentiation and progression, and allowed the discovery of several alterations underlying the deregulation of cell cycle and signalling pathways. This review provides an interpretive analysis of the results of these studies. Mounting evidence emphasises the role of up-regulation of RAS/ERK, P13K/AKT, IKK/NF-kB, WNT, TGF-ß, NOTCH, Hedgehog, and Hippo signalling pathways as well as of aberrant proteasomal activity in hepatocarcinogenesis. Signalling deregulation often occurs in preneoplastic stages of rodent and human hepatocarcinogenesis and progressively increases in carcinomas, being most pronounced in more aggressive tumours. Numerous changes in signalling cascades are involved in the deregulation of carbohydrate, lipid, and methionine metabolism, which play a role in the maintenance of the transformed phenotype. Recent studies on the role of microRNAs in signalling deregulation, and on the interplay between signalling pathways led to crucial achievements in the knowledge of the network of signalling cascades, essential for the development of adjuvant therapies of liver cancer. Furthermore, the analysis of the mechanisms involved in signalling deregulation allowed the identification of numerous putative prognostic markers and novel therapeutic targets of specific hepatocellular carcinoma subtypes associated with different biologic and clinical features. This is of prime importance for the selection of patient subgroups that are most likely to obtain clinical benefit and, hence, for successful development of targeted therapies for liver cancer.

Cytokines as regulators of proliferation and survival of healthy and malignant peripheral B cells

Adaptive immunity depends on the production and maintenance of a pool of mature peripheral lymphocytes throughout life. The signals regulating the survival of mature splenic B cells have become a major focus in recent studies of B cell immunology. Lasting B cell persistence in the periphery is dependent on survival signals that are transduced by cell surface receptors. Cytokines have been shown to play a critical role in maintaining lymphocyte homeostasis. This review focuses on the role of cytokines and their receptors in the regulation of peripheral B cell survival, with an emphasis on those that have received relatively less attention in the literature.

Genome-wide analysis of hepatic gene silencing in hepatoma cell variants

Genome-wide gene expression profiling was carried out on rat hepatoma cells and compared to profiles of hepatoma "variant" cell lines derived via a stringent selection protocol that enriches for rare cells (<1 in 100,000 cells) that fail to drive liver function. Results show 132 genes that are strongly (>5-fold) repressed in each of the four variant cell lines tested. An additional 68 genes were repressed in 3 of 4 variant cell lines. Importantly, several of the repressed genes are members of transcriptional activation pathways, suggesting that they may contribute to maintaining the hepatic phenotype. Ectopic expression of the HNF1A gene in a variant cell line resulted in activation of 56 genes, 37 of which were included in the repressed data set. These data suggest that a high level of reprogramming occurs when hepatoma cells convert to a non-differentiated phenotype, a process that can be partially reversed by the introduction of transcription factors.

Midkine confers Adriamycin resistance in human gastric cancer cells

Midkine (MDK) is a heparin-binding molecule involved in the regulation of growth and differentiation during embryogenesis, which is overexpressed in most of human malignant tumors and may act as an oncoprotein. The aim of the current study was to investigate the mechanism of MDK involved in the Adriamycin (ADR) resistance in human gastric cancer cells in vitro. We found that Adriamycin-resistant SGC7901 (SGC7901/ADR) exhibited 58.6-fold greater resistance to ADR compared with Adriamycin-sensitive SGC7901 cell line. MDK mRNA and protein expression levels were significantly higher in SGC7901/ADR than in SGC7901. To gain a deeper insight into the role of MDK in SGC7901/ADR, we stably transfected Adriamycin-sensitive SGC7901 with viral vector expressing MDK. Our result showed that multidrug resistance type I (MDR1) was found in SGC7901/ADR, not in SGC7901 by RT-PCR regardless of MDK transfection. P-Glycoprotein, which is the MDR1-coded protein, was found in SGC7901/ADR, not in SGC7901 by Western blot regardless of MDK transfection. We investigated whether an activation of the tyrosine kinase pathway would change the drug resistance phenotype with MDK transfection. Western blot results showed the upregulation of phosphorylated protein kinase B (AKT) and phosphorylated extracellular signal-regulated protein kinase (ERK) in Adriamycin-sensitive SGC7901 cell by MDK transfection accompanied with drug resistance to ADR, although the level of AKT and ERK protein expression did not change, so our results suggested that MDK, which can activate AKT and ERK by phosphorylation, induced the Adriamycin resistance in gastric cancer cells. Understanding the molecular mechanisms, driving MDK-induced ADR resistance, will provide benefits in developing new therapies for gastric cancer.

Midkine in the pathology of cancer, neural disease, and inflammation

Midkine (MK) is a heparin-binding growth factor involved in various cellular processes such as cellular proliferation, survival, and migration. In addition to these typical growth factor activities, MK exhibits several other activities related to fibrinolysis, blood pressure, host defense and other processes. Many cell-surface receptors have been identified to account for the multiple biological activities of MK. The expression of MK is frequently upregulated in many types of human carcinoma. Moreover, blood MK levels are closely correlated with patient outcome. Knockdown and blockade of MK suppress tumorigenesis and tumor development. Thus, MK serves as a tumor marker and a molecular target for cancer therapy. Furthermore, there is growing evidence that MK plays pivotal roles in neural and inflammatory diseases. Understanding of the mechanisms of action of MK is expected to create new therapeutic options for several human diseases.

Midkine prevented hypoxic injury of mouse embryonic stem cells through activation of Akt and HIF-1α via low-density lipoprotein receptor-related protein-1

Stem cell functions are dramatically altered by oxygen in tissue culture, which means the antioxidant/oxidant balance is critical for protection as well as toxicity. This study examined the effect of the heparin-binding growth factor midkine (MK) on hypoxia-induced apoptosis and related signal pathways in mouse embryonic stem cells (mESCs). Hypoxia (60 h) increased lactate dehydrogenase release and apoptosis, and reduced cell viability and proliferation. These effects were reversed by MK (100 ng/ml). MK also reversed hypoxia-induced increases of intracellular reactive oxygen species, c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) phosphorylation. Blockage of JNK and p38 MAPK using small interference (si)RNAs produced a decrease in apoptosis. A loss of mitochondrial membrane potential, increases of cytochrome c release from mitochondria to cytosol, and cleaved caspase-3 expression, as well as decreases in cIAP-2 and Bcl-2 were also reversed by MK. Hypoxia alone and hypoxia with MK increased low-density lipoprotein receptor-related protein-1 (LRP-1) mRNA and protein expression. Hypoxia with MK rapidly increased serine/threonine protein kinase (Akt) phosphorylation which reversed by LRP-1 Ab (0.1 µg/ml) and prolonged heme oxygenase-1 (HO-1) expression. In addition, hypoxia with MK increased the expression of hypoxia-inducible factor-1α (HIF-1α). Moreover, inhibition of Akt, HO-1, and HIF-1α signaling pathways abolished the MK-induced blockage of apoptosis. In conclusion, MK partially prevented hypoxic injury of mESCs through activation of Akt, HO-1, and HIF-1α via LRP-1.

Mybl2 expression is under genetic control and contributes to determine a hepatocellular carcinoma susceptible phenotype

BACKGROUND & AIMS

MYBL2 is implicated in human malignancies and over expressed in hepatocellular carcinoma (HCC). We investigated Mybl2 role in the acquisition of susceptibility to HCC and tumor progression.

METHODS

MYBL2 mRNA and protein levels were evaluated by quantitative RT-PCR and immunoblotting, respectively. MYBL2 expression in HCC cell lines was controlled through MYBL2 cDNA or anti-MYBL2 siRNA transfection. Gene expression profile of cells transfected with MYBL2 was analyzed by microarray.

RESULTS

Low induction of Mybl2 and its target Clusterin mRNAs, in low-grade dysplastic nodules (DN), progressively increased in fast growing high-grade DN and HCC of F344 rats, susceptible to hepatocarcinogenesis, whereas no/lower increases occurred in slow growing lesions of resistant BN rats. Highest Mybl2 protein activation, prevalently nuclear, occurred in F344 than BN lesions. Highest Mybl2, Clusterin, Cdc2, and Cyclin B1 expression occurred in fast progressing DN and HCC of E2f1 transgenics, compared to c-Myc transgenics, and anti-Mybl2 siRNA had highest anti-proliferative and apoptogenic effects in cell lines from HCC of E2f1 transgenics. MYBL2 transfected HepG2 and Huh7 cells exhibited increased cell proliferation and G1-S and G2-M cell cycle phases. The opposite occurred when MYBL2 was silenced by specific siRNA. MYBL2 transfection in Huh7 cells led to upregulation of genes involved in signal transduction, cell proliferation, cell motility, and downregulation of oncosuppressor and apoptogenic genes.

CONCLUSIONS

mybl2 expression and activation are under genetic control. Mybl2 upregulation induces fast growth and progression of premalignant and malignant liver, through cell cycle deregulation and activation of genes and pathways related to tumor progression.

Midkine expression in human periapical granulomas

INTRODUCTION

The expression of midkine (MK), a heparin-binding growth factor, is increased in various human tumors, making it a promising tumor marker and target for tumor therapy. MK is also related to the regulation of the development and etiology of chronic or autoimmune diseases; however, the involvement of MK in apical periodontitis has never been examined. This study compared the localization of MK-expressing cells and MK messenger RNA expression in periapical granulomas with healthy gingival tissues.

METHODS

Periapical lesions were removed surgically from chronic apical periodontitis patients, and serial tissue sections were stained with hematoxylin-eosin. The lesions diagnosed as periapical granulomas pathologically were examined by immunohistochemistry using human MK monoclonal antibodies. MK messenger RNA expression was also detected using real-time polymerase chain reaction analysis. Healthy gingival tissues were analyzed in the same manner.

RESULTS

MK was expressed by inflammatory cells, such as macrophages, lymphocytes, and neutrophils, as well as by endothelial cells in periapical granulomas but not in healthy gingival tissues. The MK-expressing inflammatory cells were seen adjacent to blood vessels, which contained MK-expressing endothelial cells, suggesting the interaction of MK among these cells during the process of inflammatory cell infiltration. Quantitative analysis of MK messenger RNA expression revealed that periapical granulomas expressed significantly more MK than healthy gingival tissues.

CONCLUSIONS

These findings suggest that MK is involved in the pathogenesis of periapical granulomas.

Enhancement of vinorelbine-induced cytotoxicity and apoptosis by clomipramine and lithium chloride in human neuroblastoma cancer cell line SH-SY5Y

The aim of this work is to investigate whether clomipramine (CIM) and lithium chloride (LiCl) potentiate the cytotoxicity of vinorelbine (VNR) on SH-SY5Y human neuroblastoma cells in vitro and whether midkine (MK) can be a resistance factor for these treatments. Four groups of experiments were performed for 96 h using both monolayer and spheroid cultures of SH-SY5Y cells: (1) control group, (2) singly applied VNR, CIM, and LiCl, (3) VNR with CIM, and (4) VNR with LiCl. Their effects on monolayer and spheroid cultures were determined by evaluating cell proliferation, bromodeoxyuridine labeling index (BrdU-LI), apoptosis, cyclic adenosine monophosphate (cAMP) and midkine levels, colony-forming efficiency, spheroid size, and ultrastructure. In comparison with the control group, single and combination drug treatments significantly reduced the proliferation index (PI) for 96 h. The most potent reduction of PI was observed with VNR in combination with CIM and LiCl for all time intervals. VNR with CIM and LiCl seemed to be ineffective in reducing BrdU-LI of both monolayer cell and spheroid cultures, spheroid size, and cAMP level. VNR with LiCl increased apoptosis at 24 h, however VNR with CIM increased apoptosis at 96 h. VNR was the most potent drug in inhibiting colony-forming efficiency. The combination of VNR with CIM was the most potent in reducing midkine levels among all groups. Interestingly, the combination of VNR with LiCl led to both nuclear membrane breakdown and disappearance of the cellular membranes inside the spheroids. Both CIM and LiCl seemed to potentiate VNR-induced cytotoxicity, and MK was not a resistance factor for VNR, LiCl, and CIM.

Advances in viral-vector systemic cytokine gene therapy against cancer

Current strategies for cancer gene therapy consist mainly of direct inhibition of tumor cell growth and activation of systemic host defense mechanisms. Cytokine gene-transduced tumor cells have been used as vaccines in clinical trials, which have shown good safety profiles and some local responses but substantial lack of systemic efficacy. Cytokines should be directed at the level of gene selection and delivery, in order to identify the optimal cytokine and achieve efficient and durable cytokine expression at the level of improving immune stimulation. In this review, we will summarize the current achievements of cytokine gene therapy, especially viral-vector, and their applications in cancer treatment. Additionally, we will also discuss and propose future perspectives about cancer gene therapy.