Retinoic acid inhibits beta-catenin through suppression of Cox-2: a role for truncated adenomatous polyposis coli

A perspective on medicinal chemistry approaches towards adenomatous polyposis coli and Wnt signal based colorectal cancer inhibitors

Colorectal cancer (CRC) is one of the major causes of carcinogenic mortality in numbers only after lung and breast cancers. The mutations in adenomatous polyposis coli (APC) gene leads to formation of colorectal polyps in the colonic region and which develop as a malignant tumour upon coalition with patient related risk factors. The protein-protein interaction (PPI) of APC with Asef (A Rac specific guanine nucleotide exchange factor) overwhelms the patient's conditions by rapidly spreading in the entire colorectal region. Most mutations in APC gene occur in mutated cluster region (MCR), where it specifically binds with the cytosolic β-catenin to regulate the Wnt signalling pathway required for CRC cell adhesion, invasion, progression, differentiation and stemness in initial cell cycle phages. The current broad spectrum perspective is attempted to elaborate the sources of identification, development of selective APC inhibitors by targeting emopamil-binding protein (EBP) & dehydrocholesterol reductase-7 & 24 (DHCR-7 & 24); APC-Asef, β-catenin/APC, Wnt/β-catenin, β-catenin/TCF4 PPI inhibitors with other vital Wnt signal cellular proteins and APC/Pol-β interface of colorectal cancer. In this context, this perspective would serve as a platform for design of new medicinal agents by targeting cellular essential components which could accelerate anti-colorectal potential candidates.

Natural and synthetic retinoids in preclinical colorectal cancer models

Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality worldwide. Although targeted therapy in combination with chemotherapy in CRC prolongs the overall survival of patients with metastatic disease, acquired resistance and relapse hinder their clinical benefits. Moreover, patients with some specific genetic profile are unlikely to benefit from targeted therapy, suggesting the need for safe and effective treatment strategies. Retinoids, comprising of natural and synthetic analogs, are a class of chemical compounds that regulate cellular proliferation, differentiation, and cell death. Retinoids have been used in the clinic for several leukemias and solid tumors, either as single agents or in combination therapy. Furthermore, retinoids have shown potent chemotherapeutic and chemopreventive properties in different cancer models, including CRC. In this review, we summarize the major preclinical findings in CRC in which natural and synthetic retinoids showed promising antitumor activities and stress on the proposed mechanisms of action. Understanding of the retinoids' antitumor mechanisms would provide insights to support and warrant their development in the management of CRC.

All-trans retinoic acid and COX-2 cross-talk to regulate BMP9-induced osteogenic differentiation via Wnt/β-catenin in mesenchymal stem cells

COX-2 specific inhibitor, which has been widely used, can delay bone fracture healing and reduce osteogenic potential of bone marrow stromal cells. However, it remains unknown how to prevent these side-effects of COX-2 inhibitor. In this study, we introduced BMP9-induced osteogenic differentiation as model to evaluate whether all-trans retinoic acid (ATRA) could ameliorate these adverse effects of COX-2 specific inhibitor on bone metabolism with in vitro and in vivo experiments, and uncover the possible mechanism underlying this process. Results showed that ATRA enhanced the potential of BMP9 to induce the osteogenic markers, such as alkaline phosphates (ALP) and mineralization; but retinoic acid receptor a (RARa) inhibitor showed the reversal effects. COX-2 specific inhibitor (NS398) reduced the osteogenic markers induced by BMP9, and ATRA almost eliminated the inhibitory effect of NS398. BMP9 up-regulated the protein level of β-catenin and promoted it translocate to nucleus, and both were reduced by NS398. On the contrary, ATRA notablely attenuated the inhibitory effect of NS398 on BMP9-increased β-catenin. Exogenous RXRa obviously ameliorated the inhibitory effect of silencing COX-2 on ectopic bone formation induced by BMP9. NS398 reduced the level of phosphorylated CREB, which was almost reversed by ATRA. Besides, RXRa interacted with phosphorylated CREB directly and both were recruited at β-catenin promoter region. Thus, we demonstrated that ATRA may reverse the side-effects of COX-2 inhibitor on bone metabolism through increasing the activation of Wnt/β-catenin pathway partly.

Molecular targeted therapies in adrenal, pituitary and parathyroid malignancies

Tumourigenesis is a relatively common event in endocrine tissues. Currently, specific guidelines have been developed for common malignant endocrine tumours, which also incorporate advances in molecular targeted therapies (MTT), as in thyroid cancer and in gastrointestinal neuroendocrine malignancies. However, there is little information regarding the role and efficacy of MTT in the relatively rare malignant endocrine tumours mainly involving the adrenal medulla, adrenal cortex, pituitary, and parathyroid glands. Due to the rarity of these tumours and the lack of prospective studies, current guidelines are mostly based on retrospective data derived from surgical, locoregional and ablative therapies, and studies with systemic chemotherapy. In addition, in many of these malignancies the prognosis remains poor with individual patients responding differently to currently available treatments, necessitating the development of new personalised therapeutic strategies. Recently, major advances in the molecular understanding of endocrine tumours based on genomic, epigenomic, and transcriptome analysis have emerged, resulting in new insights into their pathogenesis and molecular pathology. This in turn has led to the use of novel MTTs in increasing numbers of patients. In this review, we aim to present currently existing and evolving data using MTT in the treatment of adrenal, pituitary and malignant parathyroid tumours, and explore the current utility and effectiveness of such therapies and their future evolution.

A metabolic switch controls intestinal differentiation downstream of Adenomatous polyposis coli (APC)

Elucidating signaling pathways that regulate cellular metabolism is essential for a better understanding of normal development and tumorigenesis. Recent studies have shown that mitochondrial pyruvate carrier 1 (MPC1), a crucial player in pyruvate metabolism, is downregulated in colon adenocarcinomas. Utilizing zebrafish to examine the genetic relationship between MPC1 and Adenomatous polyposis coli (APC), a key tumor suppressor in colorectal cancer, we found that apc controls the levels of mpc1 and that knock down of mpc1 recapitulates phenotypes of impaired apc function including failed intestinal differentiation. Exogenous human MPC1 RNA rescued failed intestinal differentiation in zebrafish models of apc deficiency. Our data demonstrate a novel role for apc in pyruvate metabolism and that pyruvate metabolism dictates intestinal cell fate and differentiation decisions downstream of apc.

DOI:http://dx.doi.org/10.7554/eLife.22706.001

Colon cancer remains an important problem in healthcare. Cancer researchers are looking for new ways to detect the disease earlier and treat it more effectively. This is challenging because many of the genetic and molecular causes of colon cancer are still poorly understood. Mutations in the gene that encodes a protein called APC are one of the major causes of the disease. The APC protein normally keeps cells from growing and dividing too fast or in an uncontrolled way and is hence referred to as a tumor suppressor. For example, APC induces stem cells in the intestine to develop into specialized cells that keep the gut working normally. Mutations in tumor suppressor genes are common in many cancers.

Other research has shown that cancer cells must reprogram their own metabolism – in other words, all the chemical processes that keep the cell alive – to meet the demands of proliferating rapidly. In particular, recent studies reveal that colon cancer cells produce less of a protein called mpc1, which is involved in metabolism. These discoveries raised the following questions: does APC have an additional role in maintaining normal metabolism in cells by controlling how much mpc1 is produced? Do mutations in the gene for APC lead to colon cancer because they alter the cell’s metabolism?

Sandoval et al. have now discovered a connection between APC and changes in cancer cells that help them to adapt to a new metabolic program. Experiments with zebrafish – a model animal that is now commonly used in the field of cancer biology – showed that APC acts via mpc1 to regulate how the cell uses energy. This regulation goes awry in colon cells that have abnormal APC activity; however, restoring the cell’s metabolism back to normal was enough to induce cells in the intestine to develop properly.

Together, these findings suggest that restoring the normal balance of energy production in colon cancer cells may be an effective way to make the cells behave normally. This hypothesis remains to be tested and, if confirmed, further studies will be needed to determine whether it will lead to new treatments for colon cancer in humans.

DOI:http://dx.doi.org/10.7554/eLife.22706.002

Modeling intestinal disorders using zebrafish

Although the zebrafish was initially developed as a model system to study embryonic development, it has gained increasing attention as an advantageous system to investigate human diseases, including intestinal disorders. Zebrafish embryos develop rapidly, and their digestive system is fully functional and visible by 5days post fertilization. There is a large degree of homology between the intestine of zebrafish and higher vertebrate organisms in terms of its cellular composition and function as both a digestive and immune organ. Furthermore, molecular pathways regulating injury and immune responses are highly conserved. In this chapter, we provide an overview of studies addressing developmental and physiological processes relevant to human intestinal disease. These studies include those related to congenital disorders, host-microbiota interactions, inflammatory diseases, motility disorders, and intestinal cancer. We also highlight the utility of zebrafish to functionally validate candidate genes identified through mutational analyses and genome-wide association studies, and discuss methodologies to investigate the intestinal biology that are unique to zebrafish.

Prostaglandin signaling regulates nephron segment patterning of renal progenitors during zebrafish kidney development

Kidney formation involves patterning events that induce renal progenitors to form nephrons with an intricate composition of multiple segments. Here, we performed a chemical genetic screen using zebrafish and discovered that prostaglandins, lipid mediators involved in many physiological functions, influenced pronephros segmentation. Modulating levels of prostaglandin E2 (PGE₂) or PGB₂ restricted distal segment formation and expanded a proximal segment lineage. Perturbation of prostaglandin synthesis by manipulating Cox1 or Cox2 activity altered distal segment formation and was rescued by exogenous PGE₂. Disruption of the PGE₂ receptors Ptger2a and Ptger4a similarly affected the distal segments. Further, changes in Cox activity or PGE₂ levels affected expression of the transcription factors irx3b and sim1a that mitigate pronephros segment patterning. These findings show for the first time that PGE₂ is a regulator of nephron formation in the zebrafish embryonic kidney, thus revealing that prostaglandin signaling may have implications for renal birth defects and other diseases.

DOI:http://dx.doi.org/10.7554/eLife.17551.001

Role of retinoids in the prevention and treatment of colorectal cancer

Vitamin A and its derivatives, retinoids, have been widely studied for their use as cancer chemotherapeutic agents. With respect to colorectal cancer (CRC), several critical mutations dysregulate pathways implicated in progression and metastasis, resulting in aberrant Wnt/β-catenin signaling, gain-of-function mutations in K-ras and phosphatidylinositol-3-kinase/Akt, cyclooxygenase-2 over-expression, reduction of peroxisome proliferator-activated receptor γ activation, and loss of p53 function. Dysregulation leads to increased cellular proliferation and invasion and decreased cell-cell interaction and differentiation. Retinoids affect these pathways by various mechanisms, many involving retinoic acid receptors (RAR). RAR bind to all-trans-retinoic acid (ATRA) to induce the transcription of genes responsible for cellular differentiation. Although most research concerning the chemotherapeutic efficacy of retinoids focuses on the ability of ATRA to decrease cancer cell proliferation, increase differentiation, or promote apoptosis; as CRC progresses, RAR expression is often lost, rendering treatment of CRCs with ATRA ineffective. Our laboratory focuses on the ability of dietary vitamin A to decrease CRC cell proliferation and invasion via RAR-independent pathways. This review discusses our research and others concerning the ability of retinoids to ameliorate the defective signaling pathways listed above and decrease tumor cell proliferation and invasion through both RAR-dependent and RAR-independent mechanisms.

The lure of zebrafish in liver research: regulation of hepatic growth in development and regeneration

The liver is an essential organ that plays a pivotal role in metabolism, digestion and nutrient storage. Major efforts have been made to develop zebrafish (Danio rerio) as a model system to study the pathways regulating hepatic growth during liver development and regeneration. Zebrafish offer unique advantages over other vertebrates including in vivo imaging at cellular resolution and the capacity for large-scale chemical and genetic screens. Here, we review the cellular and molecular mechanisms that regulate hepatic growth during liver development in zebrafish. We also highlight emerging evidence that developmental pathways are reactivated following liver injury to facilitate regeneration. Finally, we discuss how zebrafish have transformed drug discovery efforts and enabled the identification of drugs that stimulate hepatic growth and provide hepatoprotection in pre-clinical models of liver injury, with the ultimate goal of identifying novel therapeutic approaches to treat liver disease.

Development of Small Molecules Targeting the Wnt Signaling Pathway in Cancer Stem Cells for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) was ranked third in morbidity and mortality in the United States in 2013. Although substantial progress has been made in surgical techniques and postoperative chemotherapy in recent years, the prognosis for colon cancer is still not satisfactory, mainly because of cancer recurrence and metastasis. The latest studies have shown that cancer stem cells (CSCs) play important roles in cancer recurrence and metastasis. Drugs that target CSCs might therefore have great therapeutic potential in prevention of cancer recurrence and metastasis. The wingless-int (Wnt) signaling pathway in CSCs has been suggested to play crucial roles in colorectal carcinogenesis, and has become a popular target for anti-CRC therapy. Dysregulation of the Wnt signaling pathway, mostly by inactivating mutations of the adenomatous polyposis coli tumor suppressor or oncogenic mutations of β-catenin, has been implicated as a key factor in colorectal tumorigenesis. Abnormal increases of β-catenin levels represents a common pathway in Wnt signaling activation and is also observed in other human malignancies. These findings highlight the importance of developing small-molecule drugs that target the Wnt pathway. Herein we provide an overview on the current development of small molecules that target the Wnt pathway in colorectal CSCs and discuss future research directions.

Juvenile ovary to testis transition in zebrafish involves inhibition of ptges

The sex differentiation mechanisms in zebrafish (Danio rerio) remains elusive, partly because of the absence of sex chromosomes but also because the process appears to depend on the synchrony of multiple genes and possibly environmental factors. Zebrafish gonadal development is initiated through the development of immature oocytes. Depending on multiple signaling cues, in about half of the individuals, the juvenile ovaries degenerate or undergo apoptosis to initiate testes development while the other half maintains the oogenic pathway. We have previously shown that activation of NFκB and prostaglandin synthase 2 (ptgs2) results in female-biased sex ratios. Prostaglandin synthase and prostaglandins are involved in multiple physiological functions, including cell survival and apoptosis. In the present study, we show that inhibition of ptgs2 by meloxicam results in male-biased sex ratios. On further evaluation, we observed that exposure with the prostaglandin D2 (PGD2) analogue BW-245C induced SRY-box containing gene 9a (sox9a) and resulted in male-biased sex ratios. On the other hand, prostaglandin E2 (PGE2) treatment resulted in female-biased sex ratios and involved activation of NFκB and the β-catenin pathway as well as inhibition of sox9. Exposure to the β-catenin inhibitor PNU-74654 resulted in up-regulation of ptgds and male-biased sex ratios, further confirming the involvement of β-catenin in the female differentiation pathway. In this study, we show that PGD2 and PGE2 can program the gonads to either the testis or the ovary differentiation pathways, indicating that prostaglandins are involved in the regulation of zebrafish gonadal differentiation.

RARα2 expression confers myeloma stem cell features

We previously demonstrated that RARα2 expression is increased in CD138 selected plasma cells of relapsed multiple myelomas (MMs), and increased expression was linked to poor prognosis in newly diagnosed MM patients. In the present study, we demonstrate that increased RARα2 confers myeloma stem cell features. Higher expression of RARα2 was identified in the multiple myeloma stem cell (MMSC) fraction. Overexpression of RARα2 in bulk MM cell lines resulted in: 1) increased drug resistance; 2) increased clonogenic potential; 3) activation of both Wnt and Hedgehog (Hh) pathways; 4) increased side population and aldehyde dehydrogenase levels; and 5) increased expression of embryonic stem cell genes. The opposite effects were seen with RARα2 knockdown. We demonstrate that RARα2 induces drug resistance by activating the drug efflux pump gene ABCC3 and anti-apoptotic Bcl-2 family members. Inhibition of Wnt signaling or ABCC3 function could overcome drug resistance in RARα2 overexpressing MM cells. We also showed that in the 5TGM1 mouse model, targeting of the Wnt and Hh pathways using CAY10404, cyclopamine, or itraconazole significantly reduced the myeloma tumor burden and increased survival. Targeting RARα2 or its downstream signaling pathways provides a potential strategy to eliminate MMSC.

Differential expression of syndecan-1 mediates cationic nanoparticle toxicity in undifferentiated versus differentiated normal human bronchial epithelial cells

Most in vitro toxicity studies on engineered nanomaterials (ENMs) use transformed rather than primary cells for logistical reasons. However, primary cells may provide a more appropriate connection to in vivo toxicity because these cells maintain their phenotypic fidelity and are also capable of differentiating into lineages that may be differently affected by potentially hazardous ENMs. Few studies to date have focused on the role of cellular differentiation in determining ENM toxicity. We compared the response of undifferentiated and differentiated primary human bronchial epithelial (NHBE) cells to cationic mesoporous silica nanoparticles (MSNPs) that are coated with polyethyleneimine (PEI) since this polymer is known to exert differential cytotoxicity depending on its molecular weight and cationic density. The attachment of cationic PEI polymers to the MSNP surface was used to assess these materials' toxicological potential in undifferentiated and differentiated human bronchial epithelial cells, using a multiparametric assay that screens for an integrated set of sublethal and lethal response outcomes. MSNPs coated with high molecular weight (10 and 25 kD) polymers were more toxic in differentiated cells than particles coated with shorter length polymers. The increased susceptibility of the differentiated cells is in agreement with more abundant expression of a proteoglycan, syndecan-1, which contains copious heparin sulfate side chains. Pretreatment with heparinase to remove the negatively charged sulfates decreased MSNP-PEI binding to the cell surface and lowered the cytotoxic potential of the cationic particles. These data demonstrate the importance of studying cellular differentiation as an important variable in the response of primary cells to toxic ENM properties.

DNA demethylase activity maintains intestinal cells in an undifferentiated state following loss of APC

Although genome-wide hypomethylation is a hallmark of many cancers, roles for active DNA demethylation during tumorigenesis are unknown. Here, loss of the APC tumor suppressor gene causes upregulation of a DNA demethylase system and the concomitant hypomethylation of key intestinal cell fating genes. Notably, this hypomethylation maintained zebrafish intestinal cells in an undifferentiated state that was released upon knockdown of demethylase components. Mechanistically, the demethylase genes are directly activated by Pou5f1 and Cebpβ and are indirectly repressed by retinoic acid, which antagonizes Pou5f1 and Cebpβ. Apc mutants lack retinoic acid as a result of the transcriptional repression of retinol dehydrogenase l1 via a complex that includes Lef1, Groucho2, Ctbp1, Lsd1, and Corest. Our findings imply a model wherein APC controls intestinal cell fating through a switch in DNA methylation dynamics. Wild-type APC and retinoic acid downregulate demethylase components, thereby promoting DNA methylation of key genes and helping progenitors commit to differentiation.

Regulation of the apoptosis-inducing kinase DRAK2 by cyclooxygenase-2 in colorectal cancer

Background:

Cyclooxygenase-2 (COX-2) is over-expressed in colorectal cancer (CRC), rendering tumour cells resistant to apoptosis. Selective COX-2 inhibition is effective in CRC prevention, although having adverse cardiovascular effects, thus focus has shifted to downstream pathways.

Methods:

Microarray experiments identified genes regulated by COX-2 in HCA7 CRC cells. In vitro and in vivo regulation of DRAK2 (DAP kinase-related apoptosis-inducing kinase 2 or STK17β, an apoptosis-inducing kinase) by COX-2 was validated by qRT-PCR.

Results:

Inhibition of COX-2 induced apoptosis and enhanced DRAK2 expression in HCA7 cells (4.4-fold increase at 4 h by qRT-PCR, P=0.001), an effect prevented by co-administration of PGE₂. DRAK2 levels were suppressed in a panel of human colorectal tumours (n=10) compared to normal mucosa, and showed inverse correlation with COX-2 expression (R=−0.68, R²=0.46, P=0.03). Administration of the selective COX-2 inhibitor rofecoxib to patients with CRC (n=5) induced DRAK2 expression in tumours (2.5-fold increase, P=0.01). In vitro silencing of DRAK2 by RNAi enhanced CRC cell survival following COX-2 inhibitor treatment.

Conclusion:

DRAK2 is a serine–threonine kinase implicated in the regulation of apoptosis and is negatively regulated by COX-2 in vitro and in vivo, suggesting a novel mechanism for the effect of COX-2 on cancer cell survival.

T-cell factor 4 (tcf7l2) is the main effector of Wnt signaling during zebrafish intestine organogenesis

The Wnt pathway orchestrates cell fate decisions during embryonic development, organogenesis, and adult tissues homeostasis. T-cell factor (Tcf )/lymphoid enhancer-binding factor (Lef) transcription factors are the downstream effectors of canonical Wnt signaling. Upon Wnt signal activation, beta-catenin stabilizes and translocates to the nucleus, where it interacts with Tcfs activating the transcription of Wnt target genes. In the absence of Wnt, levels of stable beta-catenin are reduced by the action of adenomatous polyposis coli (Apc) and other cytoplasmic proteins. Mutations in Apc cause constitutive accumulation of beta-catenin and inappropriate activation of the Wnt pathway. apc(mcr/mcr) fish embryos show absence of expression of tissue-specific differentiation markers in the intestine, suggesting that inappropriate activation of Wnt signaling abrogates gut organogenesis. Which Tcf transcription factor mediates Wnt signaling during zebrafish gut organogenesis remains unclear. We studied the combined effect of loss of Tcf family members and Apc in the developing embryo. Tcf4 (tcf7l2) loss rescues the apc(mcr/mcr) phenotype in the intestine. Single depletion of Tcf1 (tcf7) and Tcf3 (tcf7l1a) function in an Apc mutant background had no effect on endoderm development. This study reveals that Tcf4 (tcf7l2) is the major effector of Wnt signaling in the intestine during zebrafish organogenesis.

A two-step model for colon adenoma initiation and progression caused by APC loss

Aberrant Wnt/beta-catenin signaling following loss of the tumor suppressor adenomatous polyposis coli (APC) is thought to initiate colon adenoma formation. Using zebrafish and human cells, we show that homozygous loss of APC causes failed intestinal cell differentiation but that this occurs in the absence of nuclear beta-catenin and increased intestinal cell proliferation. Therefore, loss of APC is insufficient for causing beta-catenin nuclear localization. APC mutation-induced intestinal differentiation defects instead depend on the transcriptional corepressor C-terminal binding protein-1 (CtBP1), whereas proliferation defects and nuclear accumulation of beta-catenin require the additional activation of KRAS. These findings suggest that, following APC loss, CtBP1 contributes to adenoma initiation as a first step, whereas KRAS activation and beta-catenin nuclear localization promote adenoma progression to carcinomas as a second step. Consistent with this model, human FAP adenomas showed robust upregulation of CtBP1 in the absence of detectable nuclear beta-catenin, whereas nuclear beta-catenin was detected in carcinomas.

Beta-catenin mediates soft tissue contracture in clubfoot

The contracted tissues from clubfeet resemble tissues from other fibroproliferative disorders such as palmar fibromatosis. Beta-catenin-mediated signaling is a crucial pathway controlling the fibroproliferative response in many fibroproliferative disorders. To determine if beta-catenin signaling plays a role in clubfoot, contracted and less contracted tissues from clubfeet were studied using Western analysis to determine the protein level of beta-catenin. Primary cell cultures were established from these tissues, and they were treated with either lithium to increase beta-catenin or Dickkopf-1 to inhibit beta-catenin. RNA was extracted from the cells and analyzed to determine how beta-catenin regulates expression of Type III collagen, an extracellular matrix protein upregulated in contracted clubfoot tissue. There was a more than twofold increase in beta-catenin protein in the contracted tissues. Treatment with either lithium or Dickkopf-1 showed Type III collagen RNA expression positively correlated with the protein level of beta-catenin. These data support the concept that beta-catenin-mediated signaling plays an important role regulating contracture in clubfeet. Because pharmacologic agents are under development to block this signaling pathway, such drugs could be used in cases of severe stiffness to improve range of motion or to decrease the need for radical surgical approaches.

Cyclooxgenase-2, β-catenin and matrix metalloproteinase-7 expression and their correlation with invasion/metastasis behaviours of hereditary nonpolyposis colorectal cancer

AIM: To detect cyclooxgenase-2 (COX-2), β-catenin (β-cat) and matrix metalloproteinase-7 (MMP-7) expression in hereditary nonpolyposis colorectal cancer (HNPCC) and sporadic colorectal carcinoma (CRC), and to analyze their relationship with the biological behaviour of HNPCC.

METHODS: The SP Immunohistochemical staining was used to detect COX-2, β-cat and MMP-7 protein expression in sample tissues of 28 HNPCC, 30 sporadic CRC and 10 normal colorectal cancer. All of the specimens were selected beforehand by hMSH2 and hMLH1 Immunohistochemical staining. And their corresponding clinical data were analyzed retrospectively.

RESULTS: The positive expression rates of COX-2, β-cat in cytoplasm and MMP-7 expression differed significantly between HNPCC and sporadic CRC (χ² = 14.8352, P = 0.0001; χ² = 5.6425, P = 0.0175; χ² = 10.6454, P = 0.0011). Positive rates of malposed β-cat and MMP-7 were closely correlated with the neoplastic invasive depth in HNPCC group and sporadic CRC group (P = 0.0127, P = 0.0001; P = 0.0227, P = 0.0261) and lymph node metastasis (P = 0.0000, P = 0.0001; P = 0.0227, P = 0.0261), but not with the sex, the size or position of the tumour. COX-2 expression was bound up with the neoplastic invasive depth (P = 0.0166) in HNPCC group, but not with the lymph node metastasis. However, in sporadic CRC group, COX-2 expression was related with neither neoplastic invasive depth nor lymph node metastasis. There was a stable positive relationship among COX-2, malposed β-cat and MMP-7 expression both in HNPCC and sporadic CRC (COX-2 and malposed β-cat: r = 0.417, P = 0.011, r = 0.504, P = 0.006; malposed β-cat and MMP-7: r = 0.396, P = 0.027, r = 0.429, P = 0.021; COX-2 and MMP-7: r = 0.315, P = 0.028, r = 0.429, P = 0.021).

CONCLUSION: The present study demonstrates that the COX-2, β-cat in cytoplasm and MMP-7 expression has marked difference among HNPCC, sporadic CRC and normal colorectal tissues. This may be an important reason why HNPCC tumors have a less invasive and metastatic potential compared with sporadic variants.

Vitamin antioxidants, lipid peroxidation, tumour stage, the systemic inflammatory response and survival in patients with colorectal cancer

Both the tumour growth and progression and the systemic inflammatory response have the potential to increase oxidative stress. We therefore examined the relationship between lipid-soluble antioxidant vitamins, lipid peroxidation, the systemic inflammatory response and survival in patients with primary operable (n = 53) and advanced inoperable (n = 53) colorectal cancer. Compared with those patients with primary operable colorectal cancer, patients with unresectable liver disease had significantly lower median concentrations of alpha-tocopherol (p < 0.001), lutein (p < 0.001), lycopene (p < 0.001), alpha-carotene (p < 0.01) and beta-carotene (p < 0.001) and higher malondialdehyde concentrations. An elevated systemic inflammatory response (Glasgow prognostic score, mGPS) was associated with a greater proportion of females (p < 0.05) and more advanced tumour stage (p < 0.05), lower circulating levels of retinol (p < 0.01), lutein (p < 0.01), lycopene (p < 0.01) and alpha- (p < 0.01) and beta-carotene but not MDA (p = 0.633). In the liver metastases group 41 patients died of their cancer and a further 1 patient died of intercurrent disease on follow-up. On univariate survival analysis, mGPS (p < 0.01), retinol (p < 0.001), alpha-tocopherol (p < 0.05) and alpha-carotene (p < 0.05) were associated significantly with cancer-specific survival. On multivariate survival analysis of these significant variables, only mGPS (p < 0.01) and retinol (p < 0.001) were independently associated with cancer-specific survival. The results of the present study showed that the systemic inflammatory response was associated with a reduction of lipid-soluble antioxidant vitamins, whereas advanced tumour stage was associated with increased lipid peroxidation in patients with colorectal cancer. Of the antioxidant vitamins measured, only retinol was independently associated with cancer-specific survival.