Calcium prevents tumorigenesis in a mouse model of colorectal cancer

Colorectal Cancer Chemoprevention: A Dream Coming True?

Colorectal cancer (CRC) is one of the deadliest forms of cancer worldwide. CRC development occurs mainly through the adenoma-carcinoma sequence, which can last decades, giving the opportunity for primary prevention and early detection. CRC prevention involves different approaches, ranging from fecal occult blood testing and colonoscopy screening to chemoprevention. In this review, we discuss the main findings gathered in the field of CRC chemoprevention, focusing on different target populations and on various precancerous lesions that can be used as efficacy evaluation endpoints for chemoprevention. The ideal chemopreventive agent should be well tolerated and easy to administer, with low side effects. Moreover, it should be readily available at a low cost. These properties are crucial because these compounds are meant to be used for a long time in populations with different CRC risk profiles. Several agents have been investigated so far, some of which are currently used in clinical practice. However, further investigation is needed to devise a comprehensive and effective chemoprevention strategy for CRC.

Fallopian tubal histogenesis of ovarian endometriosis-A study of folate receptor-alpha expression

Background

Ovary is a common organ site involved by endometriosis. We previously found that fallopian tube may contribute to the histogenesis of ovarian endometriosis. The finding was novel and requires further studies. We addressed this issue by examining a differentially expressed gene folate receptor alpha (FOLR1) and its protein (FRA) in this study.

Results

A total of 144 tissue samples were studied. These included 32-paired tubal-endometrial-ovarian endometriosis samples (n = 96), 18 samples of ovarian endometriosis without corresponding fallopian tube or endometrium, and 30 ovarian tissue samples with ovarian surface epithelia but without endometriosis. Multiple comparisons among groups of ovarian endometriosis, normal fallopian tube and benign endometrium were performed. FOLR1 was highly expressed in the epithelia of fallopian tube and ovarian endometriosis, with paired endometrial samples showing a significantly lower level of expression. Similar differential studies for FRA protein were performed through Western blot and immunohistochemistry (IHC). The expression of folate receptor alpha at both mRNA and protein levels in the tissues (fallopian tube or ovarian endometriosis vs. the endometrium) were significantly different (p < 0.001). All ovarian surface mesothelial epithelia showed negative expression of FRA by IHC.

Conclusion

The results further support that the fallopian tube may contribute to the development of ovarian endometriosis. Understanding the tubal contribution to ovarian endometriosis should ultimately contribute to ongoing investigative efforts aimed at identifying alternative ways to prevent and treat endometriosis. High level of FRA expression in the fallopian tube and endometriosis might be considered as potential tissue sites for targeted therapy.

Colon Carcinogenesis: The Interplay Between Diet and Gut Microbiota

Colorectal cancer (CRC) incidence increases yearly, and is three to four times higher in developed countries compared to developing countries. The well-known risk factors have been attributed to low physical activity, overweight, obesity, dietary consumption including excessive consumption of red processed meats, alcohol, and low dietary fiber content. There is growing evidence of the interplay between diet and gut microbiota in CRC carcinogenesis. Although there appears to be a direct causal role for gut microbes in the development of CRC in some animal models, the link between diet, gut microbes, and colonic carcinogenesis has been established largely as an association rather than as a cause-and-effect relationship. This is especially true for human studies. As essential dietary factors influence CRC risk, the role of proteins, carbohydrates, fat, and their end products are considered as part of the interplay between diet and gut microbiota. The underlying molecular mechanisms of colon carcinogenesis mediated by gut microbiota are also discussed. Human biological responses such as inflammation, oxidative stress, deoxyribonucleic acid (DNA) damage can all influence dysbiosis and consequently CRC carcinogenesis. Dysbiosis could add to CRC risk by shifting the effect of dietary components toward promoting a colonic neoplasm together with interacting with gut microbiota. It follows that dietary intervention and gut microbiota modulation may play a vital role in reducing CRC risk.

CASR rs1801725 polymorphism is associated with the risk and prognosis of colorectal cancer: A case-control study

BACKGROUND

The extracellular calcium-sensing receptor (CASR) controls body calcium homeostasis. Increased levels of calcium are associated with protecting against colorectal cancer (CRC). This study aimed to determine the relationship between CASR gene rs1801725 polymorphism and CRC risk and prognosis.

METHODS

We conducted a hospital-based case-control study and a meta-analysis to evaluate the association of CASR gene rs1801725 polymorphism with CRC susceptibility.

RESULTS

This study proved that CASR rs1801725 polymorphism was associated with a higher risk to develop CRC (TT vs GG: OR 1.92, 95% CI [1.03-3.59], P = .042; T vs G: OR 1.30, 95% CI [1.03-1.64], P = .030). Subgroup analysis showed that this polymorphism increased the risk of CRC among smokers, and those aged ≥60 years (TT vs GG: OR 3.37, 95% CI [1.12-10.14], P = .034). We also found that this polymorphism was associated with the tumor size, TNM stage, and lymph node metastasis of CRC (GT vs GG: OR 2.03, 95% CI [1.32-3.10], P = .001). In addition, CASR gene rs1801725 polymorphism correlated with the survival of CRC patients. Further meta-analysis also obtained a significant association between this SNP and CRC risk (TT + GT vs GG: OR 1.28, 95% CI [1.01, 1.63], P = .041). Subgroup analyses by ethnicity observed a link between rs1801725 polymorphism and CRC risk in Asians, but not in Caucasians and mixed populations.

CONCLUSION

In conclusion, this case-control study and meta-analysis showed that CASR rs1801725 polymorphism increased the risk of CRC. Further studies from other races are urgently needed.

The Role of Tissue-Specific Ubiquitin Ligases, RNF183, RNF186, RNF182 and RNF152, in Disease and Biological Function

Ubiquitylation plays multiple roles not only in proteasome-mediated protein degradation but also in various other cellular processes including DNA repair, signal transduction, and endocytosis. Ubiquitylation is mediated by ubiquitin ligases, which are predicted to be encoded by more than 600 genes in humans. RING finger (RNF) proteins form the majority of these ubiquitin ligases. It has also been predicted that there are 49 RNF proteins containing transmembrane regions in humans, several of which are specifically localized to membrane compartments in the secretory and endocytic pathways. Of these, RNF183, RNF186, RNF182, and RNF152 are closely related genes with high homology. These genes share a unique common feature of exhibiting tissue-specific expression patterns, such as in the kidney, nervous system, and colon. The products of these genes are also reported to be involved in various diseases such as cancers, inflammatory bowel disease, Alzheimer's disease, and chronic kidney disease, and in various biological functions such as apoptosis, endoplasmic reticulum stress, osmotic stress, nuclear factor-kappa B (NF-κB), mammalian target of rapamycin (mTOR), and Notch signaling. This review summarizes the current knowledge of these tissue-specific ubiquitin ligases, focusing on their physiological roles and significance in diseases.

The Complex Interplay between Chronic Inflammation, the Microbiome, and Cancer: Understanding Disease Progression and What We Can Do to Prevent It

Cancer is a multifaceted condition, in which a senescent cell begins dividing in an irregular manner due to various factors such as DNA damage, growth factors and inflammation. Inflammation is not typically discussed as carcinogenic; however, a significant percentage of cancers arise from chronic microbial infections and damage brought on by chronic inflammation. A hallmark cancer-inducing microbe is Helicobacter pylori and its causation of peptic ulcers and potentially gastric cancer. This review discusses the recent developments in understanding microbes in health and disease and their potential role in the progression of cancer. To date, microbes can be linked to almost every cancer, including colon, pancreatic, gastric, and even prostate. We discuss the known mechanisms by which these microbes can induce cancer growth and development and how inflammatory cells may contribute to cancer progression. We also discuss new treatments that target the chronic inflammatory conditions and their associated cancers, and the impact microbes have on treatment success. Finally, we examine common dietary misconceptions in relation to microbes and cancer and how to avoid getting caught up in the misinterpretation and over inflation of the results.

Genomic characterization of liver metastases from colorectal cancer patients

Metastatic dissemination is the most frequent cause of death of sporadic colorectal cancer (sCRC) patients. Genomic abnormalities which are potentially characteristic of such advanced stages of the disease are complex and so far, they have been poorly described and only partially understood. We evaluated the molecular heterogeneity of sCRC tumors based on simultaneous assessment of the overall GEP of both coding mRNA and non-coding RNA genes in primary sCRC tumor samples from 23 consecutive patients and their paired liver metastases. Liver metastases from the sCRC patients analyzed, systematically showed deregulated transcripts of those genes identified as also deregulated in their paired primary colorectal carcinomas. However, some transcripts were found to be specifically deregulated in liver metastases (vs. non-tumoral colorectal tissues) while expressed at normal levels in their primary tumors, reflecting either an increased genomic instability of metastatic cells or theiradaption to the liver microenvironment. Newly deregulated metastatic transcripts included overexpression of APOA1, HRG, UGT2B4, RBP4 and ADH4 mRNAS and the miR-3180-3p, miR-3197, miR-3178, miR-4793 and miR-4440 miRNAs, together with decreased expression of the IGKV1-39, IGKC, IGKV1-27, FABP4 and MYLK mRNAS and the miR-363, miR-1, miR-143, miR-27b and miR-28-5p miRNAs. Canonical pathways found to be specifically deregulated in liver metastatic samples included multiple genes related with intercellular adhesion and the metastatic processes (e.g., IGF1R, PIK3CA, PTEN and EGFR), endocytosis (e.g., the PDGFRA, SMAD2, ERBB3, PML and FGFR2), and the cell cycle (e.g., SMAD2, CCND2, E2F5 and MYC). Our results also highlighted the activation of genes associated with the TGFβ signaling pathway, -e.g. RHOA, SMAD2, SMAD4, SMAD5, SMAD6, BMPR1A, SMAD7 and MYC-, which thereby emerge as candidate genes to play an important role in CRC tumor metastasis.

S100A16 is a prognostic marker for colorectal cancer

BACKGROUND

S100 is a superfamily of calcium-binding proteins that regulate multiple biological processes and are involved in many diseases. S100A16 has recently been identified to be involved in several cancers such as bladder cancer, lung cancer, and oral squamous cell carcinoma. However, the role of S100A16 expression in the colorectal cancer (CRC) has not been investigated.

METHODS

S100A16 protein expression was detected by immunohistochemistry in 296 cases of CRC. Kaplan-Meier survival analysis and Cox regression analysis were performed to evaluate the prognostic significance of S100A16.

RESULT

The results showed that the overall survival (OS) of patients with low membrane S100A16 expression was significantly shorter than patients with high expression (P < 0.05). Chi-square analysis showed that S100A16 expression had a positive correlation with tumor grade (P = 0.02). Multivariate analysis identified membrane S100A16 expression as an independent prognostic marker for OS in CRC patients. (P < 0.05). Univariate analysis showed no significant association between cytoplasmic/nuclear S100A16 expression and OS.

CONCLUSION

Membrane S100A16 is associated with the prognosis of CRC patients, indicating that S100A16 may be a potential prognostic biomarker and therapeutic target for CRC.

Berberine may rescue Fusobacterium nucleatum-induced colorectal tumorigenesis by modulating the tumor microenvironment

Background

Accumulating evidence links colorectal cancer (CRC) with the intestinal microbiota. However, the disturbance of intestinal microbiota and the role of Fusobacterium nucleatum during the colorectal adenoma-carcinoma sequence have not yet been evaluated.

Methods

454 FLX pyrosequencing was used to evaluate the disturbance of intestinal microbiota during the adenoma-carcinoma sequence pathway of CRC. Intestinal microbiota and mucosa tumor-immune cytokines were detected in mice after introducing 1,2-dimethylhydrazine (DMH), F. nucleatum or Berberine (BBR), using pyrosequencing and Bio-Plex Pro™ cytokine assays, respectively. Protein expressions were detected by western blotting.

Results

The levels of opportunistic pathogens, such as Fusobacterium, Streptococcus and Enterococcus spp. gradually increased during the colorectal adenoma-carcinoma sequence in human fecal and mucosal samples. F. nucleatum treatment significantly altered lumen microbial structures, with increased Tenericutes and Verrucomicrobia (opportunistic pathogens) (P < 0.05 = in wild-type C57BL/6 and mice with DMH treatment). BBR intervention reversed the F. nucleatum-mediated increase in opportunistic pathogens, and the secretion of IL-21/22/31, CD40L and the expression of p-STAT3, p-STAT5 and p-ERK1/2 in mice, compared with mice fed with F. nucleatum alone.

Conclusions

F. nucleatum colonization in the intestine may prompt colorectal tumorigenesis. BBR could rescue F. nucleatum-induced colorectal tumorigenesis by modulating the tumor microenvironment and blocking the activation of tumorigenesis-related pathways.

Advances and perspectives of colorectal cancer stem cell vaccine

Colorectal cancer is essentially an environmental and genetic disease featured by uncontrolled cell growth and the capability to invade other parts of the body by forming metastases, which inconvertibly cause great damage to tissues and organs. It has become one of the leading causes of cancer-related mortality in the developed countries such as United States, and approximately 1.2 million new cases are yearly diagnosed worldwide, with the death rate of more than 600,000 annually and incidence rates are increasing in most developing countries. Apart from the generally accepted theory that pathogenesis of colorectal cancer consists of genetic mutation of a certain target cell and diversifications in tumor microenvironment, the colorectal cancer stem cells (CCSCs) theory makes a different explanation, stating that among millions of colon cancer cells there is a specific and scanty cellular population which possess the capability of self-renewal, differentiation and strong oncogenicity, and is tightly responsible for drug resistance and tumor metastasis. Based on these characteristics, CCSCs are becoming a novel target cells both in the clinical and the basic studies, especially the study of CCSCs vaccines due to induced efficient immune response against CCSCs. This review provides an overview of CCSCs and preparation technics and targeting factors related to CCSCs vaccines in detail.

The calcium-sensing receptor: A promising target for prevention of colorectal cancer

The inverse correlation between dietary calcium intake and the risk of colorectal cancer (CRC) is well known, but poorly understood. Expression of the calcium-sensing receptor (CaSR), a calcium-binding G protein-coupled receptor is downregulated in CRC leading us to hypothesize that the CaSR has tumor suppressive roles in the colon. The aim of this study was to understand whether restoration of CaSR expression could reduce the malignant phenotype in CRC. In human colorectal tumors, expression of the CaSR negatively correlated with proliferation markers whereas loss of CaSR correlated with poor tumor differentiation and reduced apoptotic potential. In vivo, dearth of CaSR significantly increased expression of proliferation markers and decreased levels of differentiation and apoptotic markers in the colons of CaSR/PTH double knock-out mice confirming the tumor suppressive functions of CaSR. In vitro CRC cells stably overexpressing wild-type CaSR showed significant reduction in proliferation, as well as increased differentiation and apoptotic potential. The positive allosteric modulator of CaSR, NPS R-568 further enhanced these effects, whereas treatment with the negative allosteric modulator, NPS 2143 inhibited these functions. Interestingly, the dominant-negative mutant (R185Q) was able to abrogate these effects. Our results demonstrate a critical tumor suppressive role of CaSR in the colon. Restoration of CaSR expression and function is linked to regulation of the balance between proliferation, differentiation, and apoptosis and provides a rationale for novel strategies in CRC therapy.

Inhibition of 4-nitroquinoline-1-oxide-induced oral carcinogenesis by dietary calcium

Calcium is a strong inducer of keratinocyte differentiation. We have previously demonstrated that extracellular calcium promotes keratinocyte differentiation via E-cadherin-catenin complex-mediated phospholipase C-γ1 (PLC-γ1) activation in the plasma membrane. However, it is unclear whether dietary calcium regulates keratinocyte proliferation, differentiation or carcinogenesis. To address this issue, the rates of oral tumor and levels of proliferation and differentiation in the oral epithelium were assessed in mice on different calcium diets and the carcinogen 4-nitroquinoline-1-oxide. The results showed that mice on the high calcium diet had lower rates of oral tumors, lower levels of proliferation and higher levels of differentiation in the normal oral epithelium than those on the normal calcium diet. Higher levels of E-cadherin, β-catenin, p120-catenin (p120), epidermal growth factor receptor (EGFR), and calcium and lower levels of PLC-γ1 were also noted in the normal oral epithelium in mice on high calcium diet than the control mice. In contrast, mice on low calcium diet had opposite effects. However, dietary calcium had no effect on the proliferation, differentiation or the levels of E-cadherin, β-catenin, p120, PLC-γ1 and EGFR in oral tumors. These data indicate that dietary calcium increases calcium levels in oral epithelium, suppresses oral carcinogenesis, inhibits proliferation and promotes differentiation of normal oral epithelium. Increased E-cadherin, β-catenin, p120 and EGFR and decreased PLC-γ1 may participate in the inhibitory effect of dietary calcium in oral carcinogenesis.

The calcium-sensing receptor suppresses epithelial-to-mesenchymal transition and stem cell- like phenotype in the colon

BACKGROUND

The calcium sensing receptor (CaSR), a calcium-binding G protein-coupled receptor is expressed also in tissues not directly involved in calcium homeostasis like the colon. We have previously reported that CaSR expression is down-regulated in colorectal cancer (CRC) and that loss of CaSR provides growth advantage to transformed cells. However, detailed mechanisms underlying these processes are largely unknown.

METHODS AND RESULTS

In a cohort of 111 CRC patients, we found significant inverse correlation between CaSR expression and markers of epithelial-to-mesenchymal transition (EMT), a process involved in tumor development in CRC. The colon of CaSR/PTH double-knockout, as well as the intestine-specific CaSR knockout mice showed significantly increased expression of markers involved in the EMT process. In vitro, stable expression of the CaSR (HT29(CaSR)) gave a more epithelial-like morphology to HT29 colon cancer cells with increased levels of E-Cadherin compared with control cells (HT29(EMP)). The HT29(CaSR) cells had reduced invasive potential, which was attributed to the inhibition of the Wnt/β-catenin pathway as measured by a decrease in nuclear translocation of β-catenin and transcriptional regulation of genes like GSK-3β and Cyclin D1. Expression of a spectrum of different mesenchymal markers was significantly down-regulated in HT29(CaSR) cells. The CaSR was able to block upregulation of mesenchymal markers even in an EMT-inducing environment. Moreover, overexpression of the CaSR led to down-regulation of stem cell-like phenotype.

CONCLUSIONS

The results from this study demonstrate that the CaSR inhibits epithelial-to-mesenchymal transition and the acquisition of a stem cell-like phenotype in the colon of mice lacking the CaSR as well as colorectal cancer cells, identifying the CaSR as a key molecule in preventing tumor progression. Our results support the rationale to develop new strategies either preventing CaSR loss or reversing its silencing.

Tubal origin of ovarian endometriosis

Endometriosis is a puzzling and debilitating disease that affects millions of women around the world. Ovary is the most common organ site involved by endometriosis. Despite various hypotheses about its cell of origin, uncertainty remains. On the basis of our clinicopathologic observations, we hypothesize that fallopian tube may contribute the histogenesis of ovarian endometriosis. To examine if the hypothesis, tubal origin of ovarian endometriosis, has scientific supporting evidence, we identified a set of novel genes, which are either highly expressed in the normal fallopian tube or in the endometrium through a gene differential array study. Among many differentially expressed genes, FMO3 and DMBT1 were selected as the initial biomarkers to test the hypothesis. These biomarkers were then validated in ovarian sections with foci of endometriosis by comparing their expression levels in the fallopian tube and the endometrium within the same patients with real-time PCR, western blot and immunohistochemistry analysis. FMO3 was highly expressed in the tubal epithelia while low in the paired endometrium. In contrast, DMBT1 was high in the endometrium but low in the fallopian tube. In 32 ovarian endometriosis cases analyzed by real-time PCR, 18 (56%) showed a high level of FMO3 and a low level of DMBT1 expression. However, 14 (44%) endometriosis cases showed a reversed expression pattern with these two markers. Results were similarly seen in the methods of western blot and immunohistochemistry. The findings suggest that approximately 60% of the ovarian endometriosis we studied may be derived from the fallopian tube, whereas about 40% of the cases may be of endometrial origin. The fallopian tube epithelia may represent one of the tissue sources contributing to ovarian endometriosis. Such novel findings, which require confirmation, may have a significant clinical impact in searching for alternative ways of prevention and treatment of endometriosis.

Consensus on the Prevention, Screening, Early Diagnosis and Treatment of Colorectal Tumors in China: Chinese Society of Gastroenterology, October 14-15, 2011, Shanghai, China

BACKGROUND

Colorectal cancer (CRC) is steadily increasing in China. Colorectal adenoma (CRA) is the most important precancerous disease of CRC. Screening for colorectal tumors can aid early diagnosis. Advances in endoscopic mucosal resection and endoscopic submucosal dissection can aid the early treatment of colorectal tumors. Furthermore, because of high risk of recurrence after removal of adenomas under endoscopy, factors contributing to recurrence, the follow-up mode and the interval established, and the feasibility of application and the time of various chemical preventions should be concerned. However, a relevant consensus on the screening, early diagnosis and treatment, and prevention of colorectal tumors in China is lacking.

SUMMARY

The consensus recommendations include epidemiology, pathology, screening, early diagnosis, endoscopic treatment, monitoring and follow-up, and chemoprevention of colorectal tumors in China.

KEY MESSAGE

This is the first consensus on the prevention, screening, early diagnosis and treatment of CRA and CRC in China based on evidence in the literature and on local data.

PRACTICAL IMPLICATIONS

Through reviewing the literature, regional data and passing the consensus by an anonymous vote, gastroenterology experts from all over China launch the consensus recommendations in Shanghai. The incidence and mortality of CRC in China has increased, and the incidence or detection rate of CRA has increased rapidly. Screening for colorectal tumors should be performed at age 50-74 years. Preliminary screening should be undertaken to find persons at high risk, followed by colonoscopy. A screening cycle of 3 years is recommended for persistent interventions. Opportunistic screening is a mode suitable for the current healthcare system and national situation. Colonoscopy combined with pathological examination is the standard method for the diagnosis of colorectal tumors. CRA removal under endoscopy can prevent CRC to some extent, but CRA has an obvious recurrence trend. The follow-up interval after the removal or surgery of colorectal tumors should be different with lesions. Primary prevention of CRA includes improved diet with more fiber, supplements containing calcium and vitamin D, supplements containing folic acid for those with low hemoglobin levels, and cessation of tobacco smoking. Non-steroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors have been recognized to prevent recurrence after adenoma removal.

Daucosterol promotes the proliferation of neural stem cells

Neural stem cells (NSCs) are self-regenerating cells, but their regenerative capacity is limited. The present study was conducted to investigate the effect of daucosterol (a sterolin) on the promotion of NSC proliferation and determine the corresponding molecular mechanism. Results of cell counting kit-8 (CCK-8) assay showed that daucosterol significantly increased the quantity of viable cells and the effectiveness of daucosterol was similar to that of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). Flow cytometry detection of CFSE-labeled (CFSE, carboxyfluorescein diacetate succinimidyl ester) NSCs showed that Div Index (or the average number of cell divisions) and % Divided (or the percentage of cells that divided at least once) of the cells were increased, indicating that daucosterol increased the percentage of NSCs re-entering the cell cycle. mRNA microarray analysis showed that 333 genes that are mostly involved in the mitotic cell cycle were up-regulated. By contrast, 627 genes that are mostly involved in differentiation were down-regulated. In particular, insulin-like growth factor I (IGF1) was considered as an important regulatory gene that functionally promoted NSC proliferation, and the increased expression of IGF1 protein was validated by ELISA. In addition, the phosphorylation of AKT was increased, indicating that the proliferation-enhancing activity of daucosterol may be involved in IGF1-AKT pathway. Our study provided information about daucosterol as an efficient and inexpensive growth factor alternative that could be used in clinical medicine and research applications.

The transcription factor FOXM1 (Forkhead box M1): proliferation-specific expression, transcription factor function, target genes, mouse models, and normal biological roles

FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor, which stimulates cell proliferation and exhibits a proliferation-specific expression pattern. Accordingly, both the expression and the transcriptional activity of FOXM1 are increased by proliferation signals, but decreased by antiproliferation signals, including the positive and negative regulation by protooncoproteins or tumor suppressors, respectively. FOXM1 stimulates cell cycle progression by promoting the entry into S-phase and M-phase. Moreover, FOXM1 is required for proper execution of mitosis. Accordingly, FOXM1 regulates the expression of genes, whose products control G1/S-transition, S-phase progression, G2/M-transition, and M-phase progression. Additionally, FOXM1 target genes encode proteins with functions in the execution of DNA replication and mitosis. FOXM1 is a transcriptional activator with a forkhead domain as DNA binding domain and with a very strong acidic transactivation domain. However, wild-type FOXM1 is (almost) inactive because the transactivation domain is repressed by three inhibitory domains. Inactive FOXM1 can be converted into a very potent transactivator by activating signals, which release the transactivation domain from its inhibition by the inhibitory domains. FOXM1 is essential for embryonic development and the foxm1 knockout is embryonically lethal. In adults, FOXM1 is important for tissue repair after injury. FOXM1 prevents premature senescence and interferes with contact inhibition. FOXM1 plays a role for maintenance of stem cell pluripotency and for self-renewal capacity of stem cells. The functions of FOXM1 in prevention of polyploidy and aneuploidy and in homologous recombination repair of DNA-double-strand breaks suggest an importance of FOXM1 for the maintenance of genomic stability and chromosomal integrity.

Oral chemoprevention with acetyl salicylic Acid, vitamin D and calcium reduces the risk of tobacco carcinogen-induced bladder tumors in mice

Bladder cancer is a common urological malignancy with high recurrence rate, which may be reduced by chemoprevention. The aim was to evaluate chemoprevention in a mouse model of tobacco carcinogen-induced bladder tumors. A total of 60 A/J mice were randomized to normal diet, diet with low calcium, and diet with chemoprevention (acetyl salicylic acid, 1-alpha 25(OH)2-vitamin D3 and calcium). There were significantly fewer tumors (0 (0-0) vs. 0 (0-2), p = .045) and fewer animals with tumors (0/20 vs. 5/20, p = .045) in the chemoprevention group compared with controls. Thus, chemoprevention diet effectively reduced the tumor promoting effect of tobacco carcinogens in the mouse bladder.

Downregulation of hematopoietic MUC1 during experimental colitis increases tumor-promoting myeloid-derived suppressor cells

PURPOSE

MUC1 is a tumor-associated antigen that is aberrantly expressed in cancer and inflammatory bowel disease (IBD). Even though immune cells express low MUC1 levels, their modulations of MUC1 are important in tumor progression. Consistent with previous clinical data that show increased myeloid-derived suppressor cells (MDSCs) in IBD, we now show that downregulation of MUC1 on hematopoietic cells increases MDSCs in IBD, similar to our data in tumor-bearing mice. We hypothesize that MDSC expansion in IBD is critical for tumor progression.

EXPERIMENTAL DESIGN

To mechanistically confirm the linkage between Muc1 downregulation and MDSC expansion, we generated chimeric mice that did not express Muc1 in the hematopoietic compartment (KO→WT). These mice were used in two models of colitis and colitis-associated cancer (CAC) and their responses were compared with wild-type (WT) chimeras (WT→WT).

RESULTS

KO→WT mice show increased levels of MDSCs during colitis and increased protumorigenic signaling in the colon during CAC, resulting in larger colon tumors. RNA and protein analysis show increased upregulation of metalloproteinases, collagenases, defensins, complements, growth factors, cytokines, and chemokines in KO→WT mice as compared with WT→WT mice. Antibody-mediated depletion of MDSCs in mice during colitis reduced colon tumor formation during CAC.

CONCLUSION

Development of CAC is a serious complication of colitis and our data highlight MDSCs as a targetable link between inflammation and cancer. In addition, the lack of MUC1 expression on MDSCs can be a novel marker for MDSCs, given that MDSCs are still not well characterized in human cancers.

FOXM1 (Forkhead box M1) in tumorigenesis: overexpression in human cancer, implication in tumorigenesis, oncogenic functions, tumor-suppressive properties, and target of anticancer therapy

FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor and is also intimately involved in tumorigenesis. FOXM1 stimulates cell proliferation and cell cycle progression by promoting the entry into S-phase and M-phase. Additionally, FOXM1 is required for proper execution of mitosis. In accordance with its role in stimulation of cell proliferation, FOXM1 exhibits a proliferation-specific expression pattern and its expression is regulated by proliferation and anti-proliferation signals as well as by proto-oncoproteins and tumor suppressors. Since these factors are often mutated, overexpressed, or lost in human cancer, the normal control of the foxm1 expression by them provides the basis for deregulated FOXM1 expression in tumors. Accordingly, FOXM1 is overexpressed in many types of human cancer. FOXM1 is intimately involved in tumorigenesis, because it contributes to oncogenic transformation and participates in tumor initiation, growth, and progression, including positive effects on angiogenesis, migration, invasion, epithelial-mesenchymal transition, metastasis, recruitment of tumor-associated macrophages, tumor-associated lung inflammation, self-renewal capacity of cancer cells, prevention of premature cellular senescence, and chemotherapeutic drug resistance. However, in the context of urethane-induced lung tumorigenesis, FOXM1 has an unexpected tumor suppressor role in endothelial cells because it limits pulmonary inflammation and canonical Wnt signaling in epithelial lung cells, thereby restricting carcinogenesis. Accordingly, FOXM1 plays a role in homologous recombination repair of DNA double-strand breaks and maintenance of genomic stability, that is, prevention of polyploidy and aneuploidy. The implication of FOXM1 in tumorigenesis makes it an attractive target for anticancer therapy, and several antitumor drugs have been reported to decrease FOXM1 expression.

Cancer association study of aminoacyl-tRNA synthetase signaling network in glioblastoma

Aminoacyl-tRNA synthetases (ARSs) and ARS-interacting multifunctional proteins (AIMPs) exhibit remarkable functional versatility beyond their catalytic activities in protein synthesis. Their non-canonical functions have been pathologically linked to cancers. Here we described our integrative genome-wide analysis of ARSs to show cancer-associated activities in glioblastoma multiforme (GBM), the most aggressive malignant primary brain tumor. We first selected 23 ARS/AIMPs (together referred to as ARSN), 124 cancer-associated druggable target genes (DTGs) and 404 protein-protein interactors (PPIs) of ARSs using NCI’s cancer gene index. 254 GBM affymetrix microarray data in The Cancer Genome Atlas (TCGA) were used to identify the probe sets whose expression were most strongly correlated with survival (Kaplan-Meier plots versus survival times, log-rank t-test <0.05). The analysis identified 122 probe sets as survival signatures, including 5 of ARSN (VARS, QARS, CARS, NARS, FARS), and 115 of DTGs and PPIs (PARD3, RXRB, ATP5C1, HSP90AA1, CD44, THRA, TRAF2, KRT10, MED12, etc). Of note, 61 survival-related probes were differentially expressed in three different prognosis subgroups in GBM patients and showed correlation with established prognosis markers such as age and phenotypic molecular signatures. CARS and FARS also showed significantly higher association with different molecular networks in GBM patients. Taken together, our findings demonstrate evidence for an ARSN biology-dominant contribution in the biology of GBM.

Synergistic anti-tumor effects of combination of photodynamic therapy and arsenic compound in cervical cancer cells: in vivo and in vitro studies

The effects of As(4)O(6) as adjuvant on photodynamic therapy (PDT) were studied. As(4)O(6) is considered to have anticancer activity via several biological actions, such as free radical production and inhibition of VEGF expression. PDT or As(4)O(6) significantly inhibited TC-1 cell proliferation in a dose-dependent manner (P<0.05) by MTT assay. The anti-proliferative effect of the combination treatment was significantly higher than in TC-1 cells treated with either photodynamic therapy or As(4)O(6) alone (62.4 and 52.5% decrease compared to vehicle-only treated TC-1 cells, respectively, P<0.05). In addition, cell proliferation in combination of photodynamic therapy and As(4)O(6) treatment significantly decreased by 77.4% (P<0.05). Cell survival pathway (Naip1, Tert and Aip1) and p53-dependent pathway (Bax, p21(Cip1), Fas, Gadd45, IGFBP-3 and Mdm-2) were markedly increased by combination treatment of photodynamic therapy and As(4)O(6). In addition, the immune response in the NEAT pathway (Ly-12, CD178 and IL-2) was also modulated after combination treatment, suggesting improved antitumor effects by controlling unwanted growth-stimulatory pathways. The combination effect apparently reflected concordance with in vitro data, in restricting tumor growth in vivo and in relation to some common signaling pathways to those observed in vitro. These findings suggest the benefit of combinatory treatment with photodynamic therapy and As(4)O(6) for inhibition of cervical cancer cell growth.

Selenium enhances the efficacy of Radachlorin mediated-photodynamic therapy in TC-1 tumor development

Selenium, an essential trace element possessing anti-carcinogenic properties, can induce apoptosis in cancer cells. Our goal was to investigate the enhanced antitumor effects of photodynamic therapy (PDT) plus selenium in TC-1 tumor cells and implanted mice. Cell viability was evaluated at various time intervals after PDT treatment and/or selenium by methyl thiazolyl tetrazolium (MTT) assay. When only PDT treatment was administered to TC-1 tumor cells, TC-1 cell growth recovered over time. On the other hand, co-treatment of PDT and selenium extended the inhibition time of tumor cell growth. Co-treatment of PDT and selenium showed serious morphological changes in TC-1 cells and induced a more apoptotic population by FACS analysis. By signal transduction pathway SuperArray analysis, genes closely involved in the NFκB, p53 and phopholipase C pathways, such as VCAM1, MDM2 and FOS, were significantly downregulated at least 10-fold in TC-1 cells following PDT and selenium cotreatment. In an in vivo study, tumor-bearing mice were intravenously injected with Radachlorin 3 h before irradiation with 300 J/cm2 of light. Selenium was administered daily for 20 days. Combination therapy against the mouse tumors generated by TC-1 cells was more effective than PDT or selenium alone. These data suggest that selenium plus PDT can induce a significant tumor suppression response compared with PDT alone. Additionally, it can be an effective anticancer therapy strategy.

Toxicogenomic analysis of the gene expression changes in rat liver after a 28-day oral Tripterygium wilfordii multiglycoside exposure

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium wilfordii multiglycoside (GTW), which is an extract derived from Tripterygium wilfordii Hook.f., has been used for the treatment of rheumatoid arthritis and other immune diseases in China. However, its potential hepatotoxicity has not been completely investigated.

THE AIM OF THE STUDY

The aim of the study was to determine the hepatotoxicity of GTW in Wistar rats and to investigate the underlying cellular mechanism further by microarray analysis.

MATERIALS AND METHODS

Doses of GTW at 60, 100 and 120mg/kg/day were administered by oral gavage for subchronic toxicity in Wistar rats. Changes in the hepatic gene expression were identified with oligonucleotide microarrays at the 100-mg/kg/day dose level to study the hepatotoxic mechanism of GTW.

RESULTS AND CONCLUSIONS

A number of changes in the body weight and food consumption, absolute and relative liver weight, biochemical analysis and histopathology were observed after the subacute exposure to GTW, and a dose-dependent hepatotoxicity was observed. A total of 1312 genes were found to be significantly altered (2-fold, P<0.05), including 582 up-regulated genes and 730 down-regulated genes. According to our biological pathway analysis, the GTW resulted in aberrant gene expression in metabolic pathways and the peroxisome proliferator-activated receptor (PPAR) signaling pathway and cellular stress. Real-time PCR analyses of several genes verified these results. Consequently, our gene expression microarray study will be useful for future GTW hepatotoxicity studies.