Protumoral roles of melanoma inhibitory activity 2 in oral squamous cell carcinoma.

BACKGROUND: The role of melanoma inhibitory activity 2 (MIA2) was examined in human oral squamous cell carcinoma (OSCC). METHODS: MIA2 role was examined by immunohistochemistry of human OSCCs and knockdown studies using human 3 OSCC cell lines with MIA2 expression. RESULTS: MIA2 expression was observed in 62 (66.7%) of 93 OSCCs and was associated with tumour expansion and nodal metastasis. Melanoma inhibitory activity 2 expression was inversely correlated with intratumoral infiltration of lymphocytes. Invasion and anti-apoptotic survival were reduced by MIA2 knockdown in HSC3 cells. MOLT-3 lymphocytes infiltrating the HSC3 cell layer was enhanced by MIA2 knockdown or MIA2 depletion with the antibody. In HSC3 cells, MIA2 knockdown decreased the expressions of vascular endothelial growth factor (VEGF), VEGF-C, and VEGF-D. The downregulation of VEGF-C and -D was caused by inhibition of p38 and extracellular signal-regulated kinase (ERK)1/2, respectively. Melanoma inhibitory activity 2 was co-precipitated with integrin α4 andα5 in HSC3 cells. Integrin α4 knockdown decreased p38 phosphorylation and increased apoptosis, whereas integrin α5 knockdown decreased c-Jun N-terminal kinase (JNK) phosphorylation and apoptosis. Inhibition of JNK decreased apoptosis in the HSC3 cells. CONCLUSION: These findings suggest that the roles of MIA2 might be based on the variety of the integrins and the subtypes of mitogen-activated protein kinase.

Downregulation of miR-126 induces angiogenesis and lymphangiogenesis by activation of VEGF-A in oral cancer.

BACKGROUND: MicroRNA (miRNA)-126 (miR-126) is an endothelial-specific miRNA located within intron 7 of epidermal growth factor-like domain 7 (EGFL7). However, the role of miR-126 in cancer is controversial. METHODS: We examined the function of miR-126 in oral squamous cell carcinoma (OSCC) cells. Furthermore, a series of 118 cases with OSCC were evaluated for the expression levels of miR-126. RESULTS: MicroRNA-126 (miR-126) was associated with cell growth and regulation of vascular endothelial growth factor-A activity, and demethylation treatment increased expression levels of miR-126 and EGFL7 in OSCC cells. A significant association was found between miR-126 expression and tumour progression, nodal metastasis, vessel density, or poor prognosis in OSCC cases. In the multivariate analysis, decreased miR-126 expression was strongly correlated with disease-free survival. CONCLUSION: The present results suggest that miR-126 might be a useful diagnostic and therapeutic target in OSCC.

CD10 enhances metastasis of colorectal cancer by abrogating the anti-tumoural effect of methionine-enkephalin in the liver.

OBJECTIVE: To examine the role of CD10, a characteristic marker of liver metastasis of colorectal cancers (CRCs). DESIGN: The effect of CD10 and Met-enkephalin (MENK) in CD10-positive and -negative human CRC cells was investigated under in vitro and in vivo conditions. Human CRC samples were examined. MAIN OUTCOME MEASURE: CD10-positive and CD10-knockdown HT29 cells and CD10-negative and CD10-transfected Colo320 cells in nude mice were treated with MENK and/or the CD10 inhibitor (thiorphan). Intracellular signalling of MENK and delta-opioid receptor (DOR) was examined by immunoblotting. RESULTS: MENK inhibited the growth, invasion and survival of CRC cells following thiorphan-induced CD10 inactivation. Thiorphan suppressed liver metastasis of CD10-positive CRC cells. Inoculation of mice with CRC cells induced MENK expression in the liver. Inhibition of hepatic MENK expression by cholesterol-conjugated antisense S-oligodeoxynucleotide increased liver metastasis of CRC cells even when the cells did not express CD10. DOR activation by MENK decreased the phosphorylation of epidermal growth factor receptor and extracellular signal-regulated kinase and increased p38-dependent apoptosis. Nitric oxide was found to induce DOR expression in CRC cells. Co-treatment with thiorphan and a nitric oxide donor had a marked anti-tumour effect on liver metastasis of HT29 cells. Of 68 CRC patients, 19 (28%) showed CD10 expression, which was dependent on the extent of liver metastasis. MENK concentration in metastasis-positive human liver was higher than that in the normal liver. CONCLUSION: CD10 expression in CRC cells abrogates the anti-tumour effect of hepatic MENK by degrading it, which enhances liver metastasis of CD10-positive CRC cells.

Reg IV is a serum biomarker for gastric cancer patients and predicts response to 5-fluorouracil-based chemotherapy.

Regenerating gene family, member 4 (Reg IV), a secreted protein, is overexpressed in several cancers, including gastric cancer (GC). In the present study, we measured Reg IV levels in sera from patients with GC by enzyme-linked immunosorbent assay. We also examined the effect of forced Reg IV expression on the apoptotic susceptibility to 5-fluorouracil (5-FU). Forced expression of Reg IV inhibited 5-FU-induced apoptosis. Induction of Bcl-2 and dihydropyrimidine dehydrogenase was involved in inhibition of apoptosis. Among 36 GC patients treated with a combination chemotherapy of low-dose 5-FU and cisplatin, all 14 Reg IV-positive patients showed no change or disease progression. The serum Reg IV concentration was similar between healthy individuals (mean+/-s.e., 0.52+/-0.05 ng/ml) and patients with chronic-active gastritis (0.36+/-0.09 ng/ml). However, the serum Reg IV concentration in presurgical GC patients was significantly elevated (1.96+/-0.17 ng/ml), even at stage I. The diagnostic sensitivity of serum Reg IV (36.1%) was superior to that of serum carcinoembryonic antigen (11.5%) or carbohydrate antigen 19-9 (13.1%). These results indicate that expression of Reg IV is a marker for prediction of resistance to 5-FU-based chemotherapy in patients with GC. Serum Reg IV represents a novel biomarker for GC.

Reg IV expression is associated with cell growth and prognosis of adenoid cystic carcinoma in the salivary gland.

AIMS: Regenerating islet-derived family, member 4 (Reg IV) is associated with the progression of various cancers. The aim was to examine Reg IV expression in adenoid cystic carcinomas (ACCs) in salivary glands. METHODS AND RESULTS: Reg IV expression was detected by immunohistochemistry and compared with clinicopathological parameters. Expression of phosphorylated epidermal growth factor receptor (pEGFR), phosphorylated AKT (pAKT) and MUC2 was examined by immunohistochemistry. Reg IV function was assessed with Reg IV antisense S-oligodeoxynucleotides (AS) in ACC3 human ACC cells. Reg IV was expressed by salivary duct epithelia and acinus myoepithelia, but not in squamous epithelia. Reg IV expression was found in 41% (17/41) of ACCs, but in none of 40 oral squamous cell carcinomas (OSCCs) and was associated with nodal metastasis (P = 0.047) and poor prognosis (P = 0.012) in ACCs. Reg IV expression was associated with pEGFR (14/17, 82%) in Reg IV+ ACCs, but had no relationship with pAKT or MUC2 expression in ACCs. Cell growth was inhibited by AS treatment in Reg IV+ ACC3 cells, but not in HSC-4 OSCC cells, whereas in vitro invasion of neither cell types was affected by AS treatment. CONCLUSIONS: These results suggest that Reg IV might accelerate cell growth and disease progression of ACCs.

Expression of angiogenesis-related genes and progression of human ovarian carcinomas in nude mice.

BACKGROUND: By the time patients are diagnosed with ovarian carcinoma, peritoneal dissemination of the tumor often has occurred. The progressive growth and spread of ovarian carcinoma depend, in part, on the formation of an adequate blood supply. We determined whether the expression of genes that regulate distinct steps in angiogenesis (i.e., the formation of new blood vessels) was associated with the pattern and progressive growth of human ovarian carcinomas implanted in the peritoneal cavity of nude mice. METHODS: Five different human ovarian carcinomas were injected individually into the peritoneal cavity of female NCr-nu/nu nude mice. The expression of basic fibroblast growth factor, vascular endothelial growth factor/vascular permeability factor (VEGF/VPF), interleukin 8 (IL-8), and collagenase type IV (MMP-2 [matrix metalloproteinase-2] and MMP-9) was determined by northern blot analysis, in situ hybridization of messenger RNA, and immunohistochemical analysis. Blood vessel distribution and density, macrophage infiltration pattern, and stromal reaction were determined by immunohistochemical analysis with specific antibodies. RESULTS: Three of the carcinomas produced both solid lesions and ascitic tumors, whereas the remaining two produced only solid lesions. Two of the carcinomas produced rapidly progressive disease, two produced slow disease, and one produced intermediate disease. The formation of ascites was directly associated with expression of VEGF/ VPF, and survival was inversely associated with expression of IL-8. In rapidly growing tumors, the number of blood vessels was high throughout the lesion; in contrast, in slow-growing tumors, most vessels (and infiltrating macrophages) were located at the periphery. CONCLUSIONS: The expression of various genes that regulate angiogenesis in human ovarian carcinomas is associated with the pattern of the disease and its progression. Therefore, targeting specific genes that regulate angiogenesis could offer new approaches to the treatment of ovarian cancer.

Expression of vascular endothelial growth factor is necessary but not sufficient for production and growth of brain metastasis.

We investigated the molecular mechanisms of angiogenesis in experimental brain metastasis. Cells from six different human cancer cell lines (proven to produce visceral metastasis) were injected into the internal carotid artery of nude mice. Colon carcinoma (KM12SM) and lung adenocarcinoma (PC14PE6 and PC14Br) cells produced large, fast-growing parenchymal brain metastases, whereas lung squamous cell carcinoma (H226), renal cell carcinoma (SN12PM6), and melanoma (TXM13) cells produced only a few slow-growing brain metastases. Rapidly progressing brain metastases contained many enlarged blood vessels. The expression of VEGF mRNA and protein by the tumor cells directly correlated with angiogenesis and growth of brain metastasis. Causal evidence for the essential role of VEGF in this process was provided by transfecting PC14PE6 and KM12SM cells with antisense-VEGF165 gene, which significantly decreased the incidence of brain metastasis. In contrast, transfection of H226 human lung squamous carcinoma cells with sense-VEGF121 or sense-VEGF165 neither enhanced nor inhibited formation of brain metastases. Collectively, the results indicate that VEGF expression is necessary but not sufficient for the production of brain metastasis and that the inhibition of VEGF represents an important therapeutic target.

Heparan sulfate enhances invasion by human colon carcinoma cell lines through expression of CD44 variant exon 3.

CD44 variant exon (CD44v) 3 is a heparan sulfate-binding isoform of CD44. The role of CD44v3 in invasion and metastasis associated with heparan sulfate in colon cancer cell lines and cases of colon cancer was examined. Expression of CD44v3 mRNA and protein was observed in five of six human colorectal cancer cell lines. Colo320 and WiDr cells expressed CD44v3 at high levels. Heparan sulfate treatment increased the invasive activity of Colo320 and WiDr cells to rates 14.3 and 12.6 times higher, respectively, than that of untreated cells. However, heparan sulfate treatment did not affect cell growth. Repression of CD44v3 protein production by antisense S-oligodeoxynucleotide treatment reduced the binding affinities and capacities for heparan sulfate by Colo320 and WiDr cells in comparison with that of control cells, and it also reduced the invasiveness of both cell lines to one-fifth that of control cells. In heparan sulfate-treated Colo320 cells, the levels of CD44v3 protein in the Triton X-100-insoluble fraction and moesin-precipitated fraction were increased, suggesting that heparan sulfate treatment facilitates association of CD44 molecules with the cytoskeleton. Immunohistochemical analysis showed CD44v3 to be expressed in 21 of 37 (57%) colorectal cancer cases. Positive CD44v3 expression was associated with more advanced pathological stage and poorer prognosis than negative CD44v3 expression. These data support a role for CD44v3 in invasion and metastasis by colorectal carcinoma cells.

Telomerase activity in preneoplastic and neoplastic gastric and colorectal lesions.

Recent evidence indicates that telomerase activity may be necessary for cell immortality, which is required for the sustained and indefinite growth of most malignant cells. We analyzed telomerase activity in gastric and colorectal cancers and in gastric and colorectal precancerous lesions to determine whether malignant progression depends on the activation of telomerase and at what stage of carcinogenesis cells have detectable telomerase activity. Telomerase activity was measured by the telomeric repeat amplification protocol assay and was detected in 17 (85%) of 20 primary gastric carcinoma tissues and in 19 (95%) of 20 primary colorectal carcinomas, regardless of tumor staging and histological types. All nodal metastases, peritoneal metastases, and a recurrent gastric cancer tumor were positive. All cell lines established from gastric and colorectal cancers contained telomerase activity. In precancerous lesions, 10 (100%) of 10 colorectal tubular adenomas were telomerase positive, in addition to 3 (23%) of 13 gastric intestinal metaplasias and 1 (50%) of 2 gastric adenomas, whereas the corresponding gastric normal mucosas as well as colorectal mucosas were negative. These results indicate overall that reactivation of telomerase may occur at an early stage of carcinogenesis and may correlate well with malignant progression of gastric cancer. Telomerase activity thus may serve as a powerful additional tool for cancer diagnosis.

Prevention of intestinal toxic effects and intensification of irinotecan's therapeutic efficacy against murine colon cancer liver metastases by oral administration of the lipopeptide JBT 3002.

The induction of severe diarrhea limits the usefulness of the DNA topoisomerase I inhibitor irinotecan (CPT-11) in the treatment of advanced colon cancer. We investigated whether oral administration of the new synthetic bacterial lipopeptide, JBT 3002, encapsulated in phospholipid liposomes could prevent damage to the intestinal epithelium and lamina propria and thus allow for the parenteral administration of high-dose irinotecan to mice with established syngeneic CT-26 colon cancer liver metastases. Treatment of mice with four daily i.p. injections of 100 mg/kg irinotecan was effective against liver metastases but also resulted in loss of body weight and early death. Histopathological examination of the intestines after this treatment revealed loss of villi, epithelial vacuolation, decrease in the number of cells in the crypts in S-phase, increase in the number of apoptotic cells, and reduction in the number of lymphocytes in the lamina propria. In contrast, treatment of mice with the same irinotecan regimen after oral administration of JBT 3002 produced highly significant inhibition of liver metastases without detectable damage to the intestines. Studies that used irinotecan administered once a week for 3 weeks after pretreatment with oral JBT 3002 demonstrated significantly intensified eradication of established CT-26 liver metastases compared with treatment with once-weekly irinotecan alone. Histological studies revealed that the liver metastases in mice treated with oral JBT 3002 and i.p. irinotecan contained a higher number of macrophages than metastases in mice treated with either drug alone. In vitro studies revealed that irinotecan produced direct antiproliferative effects but JBT 3002 did not. Tumor cells exposed to both irinotecan and macrophages activated by JBT 3002 were highly susceptible to lysis. These data show that oral administration of JBT 3002 can prevent irinotecan-induced gastrointestinal toxic effects and maintain the integrity of the lamina propria, thus allowing for intensification of irinotecan therapy against liver metastases from colon cancer.

Anti-epidermal growth factor receptor antibody C225 inhibits angiogenesis in human transitional cell carcinoma growing orthotopically in nude mice.

Epidermal growth factor receptor (EGFR) regulates the growth and progression of human transitional cell carcinoma (TCC) of the bladder. We have shown that therapy targeting EGFR inhibited the growth of human TCC established orthotopically in nude mice. The purpose of this study was to evaluate whether EGFR-directed therapy affects angiogenesis associated with the growth and metastasis of human TCC. We determined the cytostatic effect and the effect on production of angiogenic factors after in vitro treatment of the human TCC cell line 253J B-V with MAb C225, a chimerized monoclonal anti-EGFR antibody. The 253J B-V cells were implanted orthotopically into athymic nude mice, and established tumors (4 weeks) were treated with i.p. MAb C225. Expression of the angiogenic factors vascular endothelial growth factor (VEGF), interleukin-8 (IL-8), and basic fibroblast growth factor (bFGF) was evaluated by immunohistochemistry and in situ mRNA hybridization analyses and correlated with microvessel density evaluated after immunohistochemical staining with anti-CD31. In vitro treatment with MAb C225 inhibited mRNA and protein production of VEGF, IL-8, and bFGF by 253J B-V cells in a dose-dependent manner. MAb C225 therapy of nude mice with established TCCs growing orthotopically resulted in inhibition of growth and metastasis compared with controls (P <0.0005). VEGF, IL-8, and bFGF expression was significantly lower in treated tumors than in controls. The down-regulation of these angiogenic factors preceded the involution of blood vessels. These studies indicate that therapy with anti-EGFR MAb C225 has a significant antitumor effect mediated, in part, by inhibition of angiogenesis.

Relative expression of E-cadherin and type IV collagenase genes predicts disease outcome in patients with resectable pancreatic carcinoma.

We examined the expression level of several genes that regulate distinct steps of metastasis in formalin-fixed, paraffin-embedded, archival specimens of primary human pancreatic carcinomas from patients undergoing curative surgery. The expression of epidermal growth factor receptor, E-cadherin, type IV collagenase [matrix metalloproteinase (MMP) 2 and MMP-9), basic fibroblast growth factor, vascular endothelial growth factor/vascular permeability factor, and interleukin 8 was examined by a colorimetric in situ mRNA hybridization technique. Down-regulation of E-cadherin and up-regulation of type IV collagenase (MMP-9 and MMP-2) at the periphery of the neoplasms (P = 0.0167, 0.0102, and 0.0349, respectively) had significant prognostic value. The ratio of type IV collagenase expression (mean of the expression of MMP-2 and MMP-9) to E-cadherin expression (MMP:E-cadherin ratio) at the periphery of the tumors was significantly higher in patients with recurrent disease (4.7 +/- 2.1) than in patients who were disease free (2.3 +/- 1.7; P = 0.0008). Death from pancreatic cancer was significantly associated with a high MMP:E-cadherin ratio (>3.0) by overall survival analysis (P < 0.0002), whereas a low MMP:E-cadherin ratio (<3.0) was found in seven of eight patients alive 28-64 months after surgery. Multivariate analysis of overall survival showed that the MMP:E-cadherin ratio was a significant independent prognostic factor, whereas stage, nodal metastasis, and histological type were not. These data show that multiparametric analysis for several metastasis-related genes may allow physicians to assess the metastatic potential and hence predict the clinical outcome of individual patients with resectable pancreatic carcinoma.

Highly metastatic human prostate cancer growing within the prostate of athymic mice overexpresses vascular endothelial growth factor.

Angiogenesis is essential for tumor progression and metastasis. It is mediated by the release of angiogenic factors by the tumor or host. We analyzed the expression of angiogenic factors by the prostate cancer cell line LNCaP and two derived variants, in vitro and in vivo, to determine whether metastatic cell lines express higher levels of these factors. The production of three angiogenic factors, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and interleukin 8 (IL-8), by LNCaP and its variants, LNCaP-LN3 (highly metastatic) and LNCaP-Pro5 (slightly metastatic), was measured by ELISA. VEGF, bFGF, and IL-8 mRNA expression was determined in vitro by Northern blot analysis. VEGF mRNA expression was determined in vivo by in situ hybridization. VEGF and flk-1 protein expression and microvessel density of LNCaP cell tumors were quantified by immunohistochemistry. In vitro, VEGF production by LNCaP-LN3 (3.15+/-0.04 pg/ml/10(3) cells) was significantly higher than those of both LNCaP (2.38+/-0.34 pg/ml/10(3) cells) and LNCaP-Pro5 (1.67+/-0.37 pg/ml/10(3) cells; P = 0.049 and 0.001, respectively). None of the three cell lines produced detectable levels of bFGF or IL-8 in vitro. In vivo, LNCaP-LN3 tumors exhibited higher levels of VEGF mRNA and protein (152.2+/-28.5 and 200.5+/-28.3) and of flk-1 protein (156.5+/-20.6) and had higher microvessel density (16.4+/-4.2) than either LNCaP tumors (89+/-17.5, 173.3+/-23.0, 124.6+/-21.6, and 12.4+/-3.5, respectively) or LNCaP-Pro5 tumors (63+/-14.7, 141.2+/-38.1, 126.1+/-20, and 5.8+/-2.2, respectively). In conclusion, metastatic human prostate cancer cells exhibited enhanced VEGF production and tumor vascularity compared with prostate cancer cells of lower metastatic potential. Thus, VEGF may play an important role in prostate cancer metastasis.

Relative expression of type IV collagenase, E-cadherin, and vascular endothelial growth factor/vascular permeability factor in prostatectomy specimens distinguishes organ-confined from pathologically advanced prostate cancers.

The tumor grade (Gleason score) in the biopsy and pretherapy prostate-specific antigen level do not accurately predict disease outcome of individual patients' prostate cancer. We used a rapid colorimetric in situ hybridization technique to evaluate the expression level of E-cadherin (which affects cell cohesion); matrix metalloproteinases (MMPs) types 2 and 9 (which affect invasion); and vascular endothelial growth factor/vascular permeability factor (which affects angiogenesis) in archival prostatectomy specimens from 40 patients. Intratumoral heterogeneity for gene expression (edge versus center versus perineural area) was more pronounced in advanced cancers than in those that were organ confined. Regardless of Gleason score, the highest expression level for E-cadherin was found in the center or perineural area of the tumors, whereas the highest expression levels for MMP-2 and MMP-9 were associated with the invasive edge. The relationship between advancing pathological stage and expression of all four metastasis-related genes was highly significant. Decreased expression of E-cadherin and increased expression of MMP-2, MMP-9, and vascular endothelial growth factor/vascular permeability factor were associated with the Gleason score of the tumors. Irrespective of serum prostate-specific antigen level or Gleason score, the ratio between expression of MMPs and E-cadherin at the invasive edge of tumors exhibited the strongest association with nonorgan-confined prostate cancer. These data suggest that the relative expression of metastasis-related genes in radical prostatectomy specimens can distinguish between organ-confined and advanced prostate cancers and provides the rationale for a prospective study correlating gene expression in pretherapy core biopsies with outcome.

Differential expression of E-cadherin and type IV collagenase genes predicts outcome in patients with stage I non-small cell lung carcinoma.

Because routine histopathological examination of primary non-small cell lung cancer does not predict disease outcome, we correlated disease outcome with the expression level of multiple genes that regulate distinct steps of the metastatic process in 60 formalin-fixed, paraffin-embedded, archival specimens of stage I lung carcinoma from patients undergoing curative surgery at the M. D. Anderson Cancer Center. The expression of E-cadherin (related to cell cohesion), type IV collagenase [matrix metalloproteinase (MMP)-2 and MMP-9, related to invasion], and three angiogenic molecules, basic fibroblast growth factor, vascular endothelial growth factor/vascular permeability factor, and interleukin 8, were examined by a colorimetric in situ mRNA hybridization technique. The expression levels of the individual genes analyzed by a Cox univariate analysis were not prognostic. In contrast, the ratio between expression of type IV collagenases (mean of the expression of MMP-2 and MMP-9) and E-cadherin, the MMP:E-cadherin ratio (measured at the periphery of each tumor), was significantly higher in patients with recurrent disease than in patients who remained disease free (P = 0.00003). Longer overall survival and reduced disease recurrence rates were significantly associated with a lower MMP:E-cadherin ratio (<2) by a Kaplan-Meier survival analysis (P = 0.0002 and P = 0.0001, respectively). Multiple covariate analyses of overall and disease-free survival also concluded that the MMP:E-cadherin ratio was a significant prognostic factor when corrected for age (P = 0.0001). Determination of this gene expression ratio in individual human lung cancers might therefore be used to direct tailored treatment for individual patients with resectable lung cancer.

Interleukin-15 and transforming growth factor alpha are associated with depletion of tumor-associated macrophages in colon cancer.

We examined the effects of IL-15 and TGF-alpha on the inhibition of macrophage infiltration into colon cancer tissue, and secretion of amphoterin from colon cancer cells. Production of IL-15 and/or TGF-alpha was associated with depletion of tumor-associated macrophages (TAMs) in both Dukes' B and C tumors (P = 0.0324 and 0.0051, respectively). Production of IL-15 and/or TGF-alpha was also associated with amphoterin mRNA expression in colon cancer tissues with TAM depletion in both Dukes' B and C tumors (P = 0.0167 and P = 0.0062, respectively). WiDr human colon cancer cells treated with IL-15 and/or TGF-alpha induced reduction of nucleus-localized amphoterin and an increase in cytosolic and membranous amphoterin. Moreover, IL-15 and/or TGF-alpha treatment increased amphoterin secretion by WiDr cells. Most notably, IL-15 and TGF-alpha treatment induced the increase of cytosol/membrane localization and secretion of amphoterin and the most pronounced effect among the treatments carried out. These results suggested that IL-15/TGF-alpha promotes depletion of TAMs and secretion of amphoterin in colon cancer.

High concentration of deoxycholic acid abrogates in vitro transformation of IEC6 intestinal cells by azoxymethane.

In this study, we designed an in vitro azoxymethane (AOM)-induced carcinogenesis model and analyzed the effect of deoxycholic acid (DCA) on growth, apoptosis, genotoxicity, and transformation of IEC6 intestinal cells. CYP2E1 production was confirmed in IEC6 cells. The growth of IEC6 cells was enhanced by DCA (100 microg/ml). However, IEC6 cells treated with DCA (200 microg/ml) were inhibited and disappeared at 48 hrs after treatment. Apoptotic cells increased 11.2 times by treatment with DCA (200 microg/ml) as compared to cells with no treatment. DNA injury detected by comet assay was found in cells treated with AOM, but not in cells treated with DCA (100 microg/ml) and AOM. The number of colony formation in soft agar increased by AOM treatment. However, the number of foci treated with DCA (100 microg/ml) plus AOM was 69% that of cells treated with AOM alone. Two out of the 6 mice subcutaneously injected with AOM-treated IEC6 cells showed tumorigenesis, whereas IEC6 cells treated with DCA (100 microg/ml) plus AOM or DCA (100 microg/ml) alone did not form any tumor. Reduced protein expression of MLH1, Bcl-2 was detected in IEC6 cells treated with DCA (100 microg/ml). Production of Bax, pJNK, TGF-beta, TGFBRI, TGFBRII, and beta-catenin were higher in IEC6 cells treated with DCA (100 microg/ml) than that in cells with no treatment. These results suggest that high-dose DCA induced apoptosis and inhibited AOM-induced in vitro transformation of IEC6 cells.

In vivo selection and characterization of metastatic variants from human pancreatic adenocarcinoma by using orthotopic implantation in nude mice.

We determined whether the implantation of human pancreatic cancer cells into the pancreas of nude mice can be used to select variants with increasing metastatic potential. COLO 357 line fast-growing cells were injected into the spleen or pancreas of nude mice. Hepatic metastases were harvested, and tumor cells were reinjected into the spleen or pancreas. This cycle was repeated several times to yield cell lines L3.6sl (spleen to liver) and L3.6pl (pancreas to liver). The variant cells produced significantly higher incidence and number of lymph node and liver metastases than the parental cells. Their increased metastatic potential was associated with increased expression (mRNA and protein) of the proangiogenic molecules basic fibroblast growth factor, vascular endothelial growth factor, and interleukin-8. The metastatic cells also exhibited increased motility and invasiveness, which were associated with increased expression of collagenase type IV (MMP-9) and decreased expression of E-cadherin. Collectively, the data show that the orthotopic implantation of human pancreatic cancer cells in nude mice is a relevant model with which to study the biology of pancreatic cancer metastasis and to select variant cell lines with enhanced metastatic potential.

High frequency of p53 gene mutation in adenocarcinomas of the gallbladder.

p53 mutations in adenocarcinomas of the gallbladder were analyzed by deoxynucleotide sequencing of the gene. Of 23 cases, 16 (70%) harbored 18 missense mutations in exon 5, 6, or 8 of the p53 gene. The characteristics of the p53 mutation spectrum observed in gallbladder carcinomas were (a) frequent mutations at an A:T pair [10 (55%) of 18 mutations], (b) high transversion incidence [12 (66%) of 18 mutations], and (c) only one mutation at the CpG site. The immunohistochemical study revealed that 36 (55%) of 65 cases showed an abnormal accumulation of p53 immunoreactivity, and 12 (52%) of 23 cases had p21 expression. No statistical correlation was observed between p53 and p21 immunoreactivity. These results suggest that p53 mutations may confer the carcinogenesis of the adenocarcinoma of the gallbladder with the specific mutation spectrum of p53.

Expression of CD44 abnormal transcripts in human gastric carcinomas.

Twenty gastric carcinoma cases were studied for the detection of CD44 aberrant transcripts using a cDNA/PCR/blot-hybridization technique which can detect splice variants containing an aberrant exon 11 of the CD44 gene. All the tumor tissues as well as their metastatic foci demonstrated overexpression of CD44 splice variants of more than 1.0 kbp than corresponding normal gastric mucosas. Six out of nine (66.7%) well-differentiated or intestinal type gastric cancers overexpressed more than three aberrant transcripts, whereas ten out of eleven (90.9%) poorly differentiated or diffuse type cancers overexpressed single or two lower molecular weight variants. These results indicate that the detection of CD44 transcription variants can serve as a powerful tool for the diagnosis of gastric cancer. It is also suggested from the difference in variant expression pattern that well-differentiated type and poorly differentiated type gastric carcinomas have different genetic pathways.