Role of the brain derived neurotrophic factor and inflammatory mediators in colon cancer

CRC is one of the most common causes of cancer death in the world. If CRC is diagnosed in the early stages, the patient's chance of survival is estimated at about 90%, with a very low probability of recurrence. The five-year DFS for CRC patients in stage III and IV drops to 63.3% and 18.9%, respectively. The current thesis aimed to identify potential new prognostic and predicting biomarkers for the detection of patients in the early stages of colon cancer. In particular, this thesis:1) studies the role of BDNF expression in stage II and III CC. By examining human biopsies, in vivo, and in vitro experiments, this study, to the best of our knowledge, for the first time shows a positive correlation between expression of CD66b, CysLT1R, and BDNF. This study suggests BDNF, alone or in combination with other known molecular markers, as a good candidate to be prognostic and predictive biomarker for early detection of CC.2) consider the problem of therapeutic resistance in CC patients and investigate the role of intermittent p-TrkB expression between the cytoplasm and nucleus. The results show that the cytoplasmic expression of TrkB and nuclear expression of CysLT1R are associated with poorer survival in CC patients. We also highlight the importance of further investigations of the role of TrkB expression in CC development3) identifies a five-gene signature as a primary prognostic and diagnostic biomarker, in 5 independent published datasets for CRC patients in-silico. In all datasets, four tumorigenic genes (BDNF, PTGS2, GSK3B, and CTNNB1) are shown to be significantly upregulated and one tumor suppressor gene (HPGD) was significantly downregulated. The four suppressive tumorigenic genes were studied in the plasma of CRC patients to evaluate the diagnostic value in the disease. The results of this study showed that the suggested five-panel gene signature, with high accuracy, can be a promising indicator for predicting OS and RFS in patients with CRC. In addition, this study suggested the four highly sensitive tumor suppressor genes as potential diagnostic markers for CRC patients. 4) investigates altered expression of estrogen receptor beta (ERβ) in CRC. High expression of ERβ is shown to correlate with antitumorigenic activity, and a higher level of CysLT2R, membrane β-catenin, and 15-hydroxy prostaglandin dehydrogenase (15-PGDH) expression, as well as lower levels of CysLT1R, COX-2, and nuclear β-catenin. The current study confirmed the antitumor role of ERb-041 (an ERβ agonist), which corresponded to an inferior ability of the tumor cells to migrate, colonize and survive, including an increased apoptosis

Repurposing phenothiazines for cancer therapy: compromising membrane integrity in cancer cells

The limitations of current cancer therapies, including the increasing prevalence of multidrug resistance, underscore the urgency for more effective treatments. One promising avenue lies in the repurposing of existing drugs. This review explores the impact of phenothiazines, primarily used as antipsychotic agents, on key mechanisms driving tumor growth and metastasis. The cationic and amphiphilic nature of phenothiazines allows interaction with the lipid bilayer of cellular membranes, resulting in alterations in lipid composition, modulation of calcium channels, fluidity, thinning, and integrity of the plasma membrane. This is especially significant in the setting of increased metabolic activity, a higher proliferative rate, and the invasiveness of cancer cells, which often rely on plasma membrane repair. Therefore, properties of phenothiazines such as compromising plasma membrane integrity and repair, disturbing calcium regulation, inducing cytosolic K-RAS accumulation, and sphingomyelin accumulation in the plasma membrane might counteract multidrug resistance by sensitizing cancer cells to membrane damage and chemotherapy. This review outlines a comprehensive overview of the mechanisms driving the anticancer activities of phenothiazines derivates such as trifluoperazine, prochlorperazine, chlorpromazine, promethazine, thioridazine, and fluphenazine. The repurposing potential of phenothiazines paves the way for novel approaches to improve future cancer treatment

PTB and TIAR binding to insulin mRNA 3′- and 5′UTRs; implications for insulin biosynthesis and messenger stability

Objectives: Insulin expression is highly controlled on the posttranscriptional level. The RNA binding proteins (RBPs) responsible for this result are still largely unknown. Methods and results: To identify RBPs that bind to insulin mRNA we performed mass spectrometry analysis on proteins that bound synthetic oligonucloetides mimicing the 5′- and the 3′-untranslated regions (UTRs) of rat and human insulin mRNA in vitro. We observed that the RBPs heterogeneous nuclear ribonucleoprotein (hnRNP) U, polypyrimidine tract binding protein (PTB), hnRNP L and T-cell restricted intracellular antigen 1-related protein (TIA-1-related protein; TIAR) bind to insulin mRNA sequences, and that the in vitro binding affinity of these RBPs changed when INS-1 cells were exposed to glucose, 3-isobutyl-1-methylxanthine (IBMX) or nitric oxide. High glucose exposure resulted in a modest increase in PTB and TIAR binding to an insulin mRNA sequence. The inducer of nitrosative stress DETAnonoate increased markedly hnRNP U and TIAR mRNA binding. An increased PTB to TIAR binding ratio in vitro correlated with higher insulin mRNA levels and insulin biosynthesis rates in INS-1 cells. To further investigate the importance of RNA-binding proteins for insulin mRNA stability, we decreased INS-1 and EndoC-βH1 cell levels of PTB and TIAR by RNAi. In both cell lines, decreased levels of PTB resulted in lowered insulin mRNA levels while decreased levels of TIAR resulted in increased insulin mRNA levels. Thapsigargin-induced stress granule formation was associated with a redistribution of TIAR from the cytosol to stress granules. Conclusions: These experiments indicate that alterations in insulin mRNA stability and translation correlate with differential RBP binding. We propose that the balance between PTB on one hand and TIAR on the other participates in the control of insulin mRNA stability and utilization for insulin biosynthesis

Identification of a Novel Five-Gene Signature as a Prognostic and Diagnostic Biomarker in Colorectal Cancers

Colorectal cancer (CRC) is one of the leading causes of cancer-related mortality worldwide. The current TNM (Tumor, Node, and Metastasis) classification approach is suboptimal in determining the prognosis of CRC patients. The prognosis for CRC is affected by a variety of features that are present at the initial diagnosis. Herein, we performed a systematic exploration and established a novel five-panel gene signature as a prognostic and early diagnosis biomarker after performing differential gene expression analyses in five independent in silico CRCs cohort and independently validating it in one clinical cohort, using immunohistochemistry. Four genes (BDNF, PTGS2, GSK3B, and CTNNB1) were significantly upregulated and one gene (HPGD) was significantly downregulated in primary tumor tissues compared with adjacent normal tissues throughout all the five in silico datasets. The univariate CoxPH analysis yielded a five-gene signature that accurately predicted overall survival (OS) and recurrence-free survival (RFS) in the in silico training (AUC = 0.73 and 0.69, respectively) and one independent in silico validation cohort (AUC = 0.69 and 0.74, respectively). This five-gene signature demonstrated significant associations with poor OS in independent clinical validation cohorts of colon cancer (CC) patients (AUC = 0.82). Intriguingly, a risk stratification model comprising of the five-gene signature together with TNM stage and gender status achieved an even superior AUC of 0.89 in the clinical cohorts. On the other hand, the circulating mRNA expression of the upregulated four-gene signature achieved a robust AUC = 0.83 with high sensitivity and specificity as a diagnosis marker in plasma from CRC patients. We have identified a novel, five-gene signature as an independent predictor of OS, which in combination with TNM stage and gender offers an easy-to-translate and facile assay for the personalized risk-assessment in CRC patients

Brain-derived neurotrophic factor, neutrophils and cysteinyl leukotriene receptor 1 as potential prognostic biomarkers for patients with colon cancer

The tumor microenvironment has been recognized as a complex network in which immune cells play an important role in cancer progression. We found significantly higher CD66b neutrophil expression in tumor tissue than in matched normal mucosa in the Malmö colon cancer (CC) cohort and poorer survival of stage I-III patients with high CD66b expression. Additionally, mice lacking CysLT1 R expression (cysltr1−/− ) produce less brain-derived neurotrophic factor (BDNF) compared to WT mice and Montelukast (a CysLT1 R antagonist)-treated mice also reduced BDNF expression in a mouse xenograft model with human SW480 CC cells. CD66b and BDNF expression was significantly higher in patient tumor tissues than in the matched normal mucosa. The univariate Cox PH analysis yielded CD66b and BDNF as an independent predictor of overall survival, which was also found in the public TCGA-COAD dataset. We also discovered a strong positive correlation between CD66b, BDNF and CysLT1 R expression in the Malmö CC cohort and in the TCGA-COAD dataset. Our data suggest that CD66b/BDNF/CysLT1 R expression as a prognostic combined biomarker signature for CC patients

Tumour-suppressive effect of oestrogen receptor β in colorectal cancer patients, colon cancer cells, and a zebrafish model

Oestrogen receptor β (ERβ) has been suggested to have anti-proliferative and anti-tumour effects in breast and prostate cancer cells, but other studies have indicated its tumour-promoting effects. Understanding the complex effects of this receptor in different contexts requires further study. We reported that high ERβ expression is independently associated with improved prognosis in female colorectal cancer (CRC) patients. Herein, we investigated the possible anti-tumour effect of ERβ and its selective agonist. CRC patients with high ERβ expression had significantly higher levels of membrane-associated β-catenin, cysteinyl leukotriene receptor 2 (CysLT2 R) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH), which have anti-tumour effects, but lower levels of nuclear β-catenin, cysteinyl leukotriene receptor 1 (CysLT1 R) and cyclooxygenase-2 (COX-2), which have tumour-promoting effects. These interesting findings were further supported by two different publicly available CRC mRNA datasets that showed a significant positive correlation between ERβ expression and 15-PGDH and CysLT2 R expression and a negative correlation between ERβ expression and β-catenin, CysLT1 R and COX-2 expression. We next evaluated ERβ expression in three different colon cancer mouse models; ERβ expression was negatively correlated with tumorigenesis. Furthermore, treatment with the ERβ-agonist ERB-041 reduced CysLT1 R, active β-catenin and COX-2 levels but increased phospho-β-catenin, CysLT2 R and 15-PGDH levels in HCT-116, Caco-2 and SW-480 colon cancer cells compared to vehicle-treated cells. Interestingly, ERB-041-treated cells showed significantly decreased migration, survival, and colonosphere formation and increased apoptotic activity, as indicated by increased CASPASE-3 and apoptotic blebs. Finally, patients with low ERβ expression had significantly more distant metastasis at the time of diagnosis than patients with high ERβ expression. Therefore, we studied the effects of ERB-041-treated colon cancer cells in a zebrafish xenograft model. We found significantly less distant metastasis of ERB-041-treated cells compared to vehicle-treated cells. These results further support ERβ's anti-tumour role in colorectal cancer and the possible use of its agonist in CRC patients