AIM: To explore the expression of leukemia related protein 16 (LRP16) in colorectal carcinoma, and analyze its correlation with clinicopathologic features and prognosis.
METHODS: Immunohistochemistry for LRP16 was performed in 201 cases of colorectal carcinoma and 60 cases of distal normal mucosa. Medical records were reviewed and clinicopathological analysis was performed.
RESULTS: LRP16 expression was detected in 117 of 201 cases of the colorectal carcinoma and in 21 cases of 60 distal normal mucosa. The expression of LRP16 in carcinoma was significantly higher than that in normal mucosa (χ2 = 9.999, P = 0.002). LRP16 protein expression was found in 43.3% (52/120) of carcinoma at stage I and II, and 80.2% (65/81) of carcinoma at stage III and IV (χ2 =27.088, P = 0.001). Correlation between LRP16 expression and clinicopathological factors was significant in differentiation (P = 0.010), tumor size (P = 0.001), infiltrative depth (P = 0.000) and distant metastasis (P = 0.027). The difference of median survival time between cancer patients with LRP16 expression (38.0 mo) and those without was statistically significant (105.0 mo, Log rank = 41.455, P = 0.001). The multivariate survival analysis revealed that LRP16 expression was correlated significantly (Cox’s regression: P = 0.001, relative risk = 2.082) with shortened survival in the patients with colorectal cancer.
CONCLUSION: The expression of LRP16 is related to the degree of differentiation, invasiveness, metastasis and prognosis of colorectal carcinoma.
Colorectal neoplasms; Immunohistochemistry; Leukemia related protein 16; Prognosis; Clinicopathology
To detect the expression of multidrug resistance molecules P-glycoprotein (P-gp), Lung resistnce protein (LRP) and Multidrug resistance-associated protein (MRP) and analyze the relationship between them and the clinico-pathological features.
The expressions of P-gp, LRP and MRP in formalin-fixed paraffin-embedded tissue sections from 59 gastric cancer patients were determined by a labbelled Streptavidin-Peroxidase (SP) immunohistochemical technique, and the results were analyzed in correlation with clinicopathological data. None of these patients received chemotherapy prior to surgery.
The positive rates of P-gp, LRP, MRP were 86.4%, 84.7% and 27.1%, respectively. The difference between the positive rate of P-gp and MRP was significant statistically, as well as the difference between the expression of MRP and LRP. No significant difference was observed between P-gp and LRP, but the positively correlation between the expression of P-gp and LRP had been found. No significant correlation between the expression of P-gp, LRP, MRP and the grade of differentiation were observed. The expression of P-gp was correlated with clinical stages positively (r = 0.742), but the difference with the expression of P-gp in different stages was not significant.
The expressions of P-gp, LRP and MRP in patients with gastric cancer without prior chemotherapy are high, indicating that innate drug resistance may exist in gastric cancer.
AIM: To analyse the expression of multidrug resistance (MDR) related proteins at different steps in colorectal carcinogenesis. METHODS: The presence of three MDR related proteins (Pgp, MRP1, and LRP/MVP) was studied by means of immunohistochemistry in normal, adenomatous, and malignant colorectal epithelium. Formaldehyde fixed, paraffin embedded tissue sections of 17 samples of colorectal tissue were used (normal mucosa, n = 4; adjacent mucosa, n = 5; adenoma, n = 5; carcinoma, n = 3). RESULTS: For all three proteins, expression was found in the surface epithelium and the upper parts of the crypts in normal colon. In the adenomas, staining was seen along the complete length of the crypts. In the carcinomas analysed, all epithelium showed positive staining. Mucosa adjacent to either carcinoma or adenoma showed staining patterns mostly resembling those of normal mucosa, but sometimes some extension of staining was seen along the crypt. CONCLUSIONS: These proteins already show increased expression in the adenoma stage. In the absence of adequate mucin production in adenomas, MDR related proteins could be an important factor in protecting the epithelium against further environmentally induced genetic damage. This could be one of the reasons why only about 5% of colorectal adenomas will actually progress to carcinomas.
LRP1 is a broadly-expressed receptor that binds multiple extracellular ligands and participates in protein clearance. LRP1 is expressed numerous cancers, but its role in lung cancer has not been characterized. Here, we investigate the relationship between LRP1 and lung cancer.
LRP1 mRNA levels were determined in lung tumors from several large, multicenter studies. LRP1 protein localization was determined by immunohistochemical analysis of lung tumor microarrays. Normal fibroblasts, fibroblasts treated with the LRP1 inhibitor RAP, and LRP1 null fibroblasts were co-cultured with three independent lung cancer cell lines to investigate the role of LRP1 on tumor cell proliferation.
LRP1 mRNA levels are significantly decreased in lung tumors relative to non-tumorous lung tissue. Lower expression of LRP1 in lung adenocarcinomas correlates with less favorable clinical outcome in a cohort of 439 patients. Immunohistochemical analysis demonstrates that LRP1 is primarily expressed in stromal cells in 94/111 lung cancers, with very little protein found in cancer cells. A growth suppressive function of mouse embryonic fibroblast cells (MEF) was observed in three lung cancer cell lines tested (H460, H2347, and HCC4006 cells); growth suppression was blocked by the LRP1 inhibitor, RAP. LRP1 deletion in fibroblasts reduced the ability of MEF cells to suppress tumor cell mitosis. In a validation set of adenocarcinomas, we confirmed a significant positive correlation between both LRP1 mRNA and protein levels and favorable clinical outcomes.
LRP1 expression is associated with improved lung cancer outcomes. Mechanistically, stromal LRP1 may non-cell autonomously suppress lung tumor cell proliferation.
Low-density lipoprotein receptor–related proteins 5 and 6 (Lrp5 and Lrp6) are co-receptors of Wnt ligands and play important roles in Wnt/β-catenin signal transduction. Mice homozygous for a germline deletion of Lrp6 die at birth with several associated defects, while Lrp5-deficient mice are viable. Here we conditionally deleted Lrp5 and/or Lrp6 in the mouse gut (gut−/−) by crossing mice carrying floxed alleles of Lrp5 and Lrp6 to a strain expressing Cre recombinase from the villin promoter (villin-Cre). The changes in morphology, differentiation and Wnt signal transduction were validated using immunohistochemistry and other staining. Consistent with observations in mice carrying a homozygous germline deletion in Lrp5, intestinal development in Lrp5gut−/− mice was normal. In addition, mice homozygous for villin-Cre–induced deletion of Lrp6 (Lrp6gut−/−) were viable with apparently normal intestinal differentiation and function. However, mice homozygous for villin-Cre inactivated alleles of both genes (Lrp5gut−/−;Lrp6gut−/−) died within one day of birth. Analysis of embryonic Lrp5gut−/−;Lrp6gut−/− intestinal epithelium showed a progressive loss of cells, an absence of proliferation, and a premature differentiation of crypt stem/precursor cells; no notable change in differentiation was observed in the embryos lacking either gene alone. Further immunohistochemical studies showed that expression of the Wnt/β-catenin target, cyclin D1, was specifically reduced in the intestinal epithelium of Lrp5gut−/−;Lrp6gut−/− embryos. Our data demonstrate that Lrp5 and Lrp6 play redundant roles in intestinal epithelium development, and that Lrp5/6 might regulate intestinal stem/precursor cell maintenance by regulating Wnt/β-catenin signaling.
Lrp5; Lrp6; Wnt/β-catenin signaling; intestine; epithelium; embryonic development
Lung resistance-related protein (LRP) and P-glycoprotein (P-gp) are associated with multidrug resistance. P-gp overexpression reduces intracellular anticancer drug concentrations and is correlated with low remission rates. However, whether the presence of LRP influences the response to induction chemotherapy remains controversial. Therefore, we investigated the relationship of LRP and P-gp overexpression with the response to induction chemotherapy. Univariate analysis revealed that there was a significant difference between complete remission rates for acute myelogenous leukemia patients depending on their blast cell expressions, between LRP positive versus negative, P-gp positive versus negative, and LRP/P-gp double positive versus other groups. Crude odds ratios (ORs) for complete remission were 0.390, 0.360, and 0.307 for LRP positive, for P-gp positive, and LRP/P-gp double positive patients, respectively. After controlling the confounding variables by stepwise multivariate logistical regression analysis, the presence of LRP/P-gp double positivity and P-gp positivity were found to be independent prognostic factors; adjusted ORs were 0.233 and 0.393, respectively. Furthermore, the monoclonal antibody against LRP significantly increased daunorubicin acumulation (P=0.004) in the nuclei of leukemic blast cells with LRP positivity in more than 10% of the cells. An LRP reversing agent, PAK-104P, was found to increase the daunorubicin content with marginal significance (P=0.060). The present results suggest that not only the presence of P-gp, but also LRP in leukemic blast cells is a risk factor for resistance to induction chemotherapy. Inhibiting LRP function, similar to the inhibition of P-gp function, will be necessary to improve the effectiveness of induction chemotherapy.
lung resistance-related protein; P-glycoprotein; reversing agent; acute myelogenous leukemia.
A recent genome-wide association study revealed that there is an association between serum uric acid (SUA) levels and rs2544390, a common variant in low-density lipoprotein-related protein 2 (LRP2/Megalin) gene. Two other variants of LRP2, rs2229268 and rs3755166, are also found to have associations with dyslipidemia and Alzheimer’s disease, respectively, which also could have a relationship with SUA in human. Although no studies report that LRP2 transports urate, LRP2 is a multi-ligand receptor and expresses in many tissues including kidney, suggesting a direct and/or indirect relationship with gout. In the present study, we investigated the association between gout and these variants of LRP2 with 741 clinically diagnosed male gout patients and 1,302 controls. As a result, the three common LRP2 variants, rs2544390, rs2229268 and rs3755166, showed no association with gout (P = 0.76, 0.55, and 0.22, respectively). Our study is the first to reveal that an SUA-related gene LRP2 is not involved in gout susceptibility.
Gouty arthritis; Hyperuricemia; Hyperlipidemia; Urate exporter; Low-density lipoprotein receptor (LDLR); LDLR gene family
The relationships between the expression of CD133, Ki-67 and prognosis in gastric adenocarcinoma are unknown and needs exploring.
The samples of gastric adenocarcinoma from 336 Chinese patients with follow-up were analyzed for CD133 and Ki-67 protein expressions by immunohistochemical method.
CD133 was expressed in up to 57.4% (193/336) of this group of gastric carcinoma. The expression of CD133 was significantly higher in carcinoma than in normal (P = 0.0001) and dysplastic mucosas (P = 0.004). CD133 was positive corresponded with the tumour size, grade, infiltrative depth and clinical stage (all P < 0.05). The overall mean survival time of the patients with CD133 positive expression was shorter than that of patients with negative expression (P = 0.0001). The expression of CD133 has a positive correlation with that of Ki-67 (r = 0.188, P = 0.001) in gastric adenocarcinoma. CD133 was an independent prognostic indicator. (P = 0.0001).
It is suggested that CD133 may play an important role in the evolution of gastric adenocarcinoma and should be considered as a potential marker for the prognosis.
Recepteur d'origine nantais (RON) is a receptor tyrosine kinase that is activated by a serum-derived, macrophage stimulating protein (MSP) growth factor and is expressed in many malignant tumors. The aim of the present study was to reveal the protein expression profile of RON and its relationship with clinicopathological characteristics of gastric carcinoma and prognosis.
Gastric carcinoma tissue from 98 patients, along with 29 specimens of paraneoplastic tissue and 10 specimens of normal gastric mucosa, were examined by immunohistochemistry (IHC). Western blot analysis of 19 samples of gastric carcinoma tissue and corresponding paraneoplastic tissue, 8 specimens of normal gastric mucosa, and 2 specimens of normal lymph node samples also detected expression of a splice variant of RON, RONΔ165. All samples obtained were accompanied by patient follow-up data that ranged from 3 to 89 months (median time: 22 months).
The rate of positive RON expression differed significantly between gastric carcinoma tissues [56.1%, (55/98)] and paraneoplastic tissues [25.6%, (8/29)] (p = 0.007). In contrast, RON expression was absent in normal gastric mucosa samples. RON expression positively correlated with the invasive depth of the tumor (p = 0.019), perigastric lymph nodes metastasis (p = 0.019), and TNM stage (p = 0.001). However, RON expression was independent of tumor growth pattern according to Bormann criteria (p = 0.209), histopathological grade (p = 0.196), and incidence of distant metastasis (p = 0.400). RON expression was not related to a patient's survival rate (p = 0.195). RONΔ165 was strongly expressed in fresh gastric carcinoma tissue, corresponding paraneoplastic tissue, and perigastric lymph nodes with metastatic carcinoma. In contrast, expression of RONΔ165 was not observed in normal gastric mucosa and normal lymph node tissue samples.
RON expression is significant in gastric carcinoma tissue and corresponding paraneoplastic tissue, but is not expressed in normal gastric mucosa. Expression of RONΔ165 was similarly observed in gastric carcinoma tissue and in metastases present in lymph node tissues. We hypothesize that RON and its splice variant play an important role in the occurrence, progression, and metastasis of gastric carcinoma, and therefore may represent a useful marker to evaluate the biological activity of gastric carcinoma.
LRP1b and the closely related LRP1 are large members of the low-density lipoprotein receptor family. At the protein level LRP1b is 55% identical to LRP1, a multifunctional and developmentally essential receptor with roles in cargo transport and cellular signaling. Somatic LRP1b mutations frequently occur in non-small cell lung cancer and urothelial cancers, suggesting a role in the modulation of cellular growth. In contrast to LRP1, LRP1b-deficient mice develop normally, most likely due to its restricted expression pattern and functional compensation by LRP1 or other receptors. LRP1b is expressed predominantly in the brain, and a differentially spliced form is present in the adrenal gland and in the testis. Despite the presence of a potential furin cleavage site and in contrast to LRP1, immunoblotting for LRP1b reveals the presence of a single 600-kDa polypeptide species. Using a yeast two-hybrid approach, we have identified two intracellular proteins, the postsynaptic density protein 95 and the aryl hydrocarbon receptor-interacting protein, that bind to the intracellular domain of LRP1b. In addition, we have found several potential ligands that bind to the extracellular domain. Analysis of LRP1b knockout mice may provide further insights into the role of LRP1b as a tumor suppressor and into the mechanisms of cancer development.
The immunolocalization of the low density lipoprotein receptor-related protein 1 (LRP1) and its ligand alpha 2-Macroglobulin (α2M) was examined in tissues from human donor eyes of normal, diabetic and sickle cell disease subjects. Streptavidin alkaline phosphatase immunohistochemistry was performed with a mouse anti-human LRP1 and rabbit anti-human α2M antibodies. Retinal and choroidal blood vessels were labeled with mouse anti-human CD34 antibody in adjacent tissue sections. Mean scores for immunostaining from the pathological and control eyes were statistically compared.
LRP1 immunoreactivity was very weak to negative in the neural retina of normal subjects except in scattered astrocytes. LRP1 expression in diabetic eyes was detected in the inner limiting membrane (ILM), astrocytes, inner photoreceptor matrix, choriocapillaris and choroidal stroma. The ligand α2M, however, was limited mainly to blood vessel walls, some areas of the inner nuclear layer (INL), photoreceptors, RPE-Bruch’s membrane–choriocapillaris complex, intercapillary septa, and choroidal stroma. In sickle cell eyes, avascular and vascular retina as well as choroidal neovascularization (CNV) were analyzed. In avascular areas, LRP1 immunoreactivity was in innermost retina (presumably ILM, astrocytes, and Muller cells) and INL as well as RPE–Bruch’s membrane–choriocapillaris complex and choroidal stroma. α2M was very weak in avascular peripheral retina compared to vascularized areas and limited to stroma in choroid. In contrast, in areas with CNV, LRP1 immunoreactivity was significantly decreased in overlying retina and in RPE–Bruch’s membrane and choroidal stroma compared to the controls, while α2M was elevated in RPE–Bruch’s membrane near CNV compared to normal areas in sickle cell choroid. The mean scores revealed that LRP1 and α2M in neural retina were significantly elevated in astrocytes and ILM in diabetic eyes (p ≤ 0.05), whereas in sickle cell eyes scores were elevated in ILM and INL (p ≤ 0.05). In addition, α2M immunoreactivity was in photoreceptors in both ischemic retinopathies. In choroid, the patterns of LRP1 and α2M expression were different and not coincident.
This is the first demonstration of the presence of LRP1 and α2M in human proliferative retinopathies. Elevated LRP1 expression in sickle cell neural retina and diabetic inner retina and choroid suggests that LRP1 plays an important role in ischemic neovascular diseases.
α2-Macroglobulin; LRP1; Diabetes Mellitus; Sickle cell disease; Ischemia
Low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional receptor involved in receptor-mediated endocytosis and cell signaling. The aim of this study was to elucidate the expression and mechanism of LRP1 in hepatocellular carcinoma (HCC).
LRP1 expression in 4 HCC cell lines and 40 HCC samples was detected. After interruption of LRP1 expression in a HCC cell line either with specific lentiviral-mediated shRNA LRP1 or in the presence of the LRP1-specific chaperone, receptor-associated protein (RAP), the role of LRP1 in the migration and invasion of HCC cells was assessed in vivo and in vitro, and the expression of matrix metalloproteinase (MMP) 9 in cells and the bioactivity of MMP9 in the supernatant were assayed. The expression and prognostic value of LRP1 were investigated in 327 HCC specimens.
Low LRP1 expression was associated with poor HCC prognosis, with low expression independently related to shortened overall survival and increased tumor recurrence rate. Expression of LRP1 in non-recurrent HCC samples was significantly higher than that in early recurrent samples. LRP1 expression in HCC cell lines was inversely correlated with their metastatic potential. After inhibition of LRP1, low-metastatic SMCC-7721 cells showed enhanced migration and invasion and increased expression and bioactivity of MMP9. Correlation analysis showed a negative correlation between LRP1 and MMP9 expression in HCC patients. The prognostic value of LRP1 expression was validated in the independent data set.
LRP1 modulated the level of MMP9 and low level of LRP1 expression was associated with aggressiveness and invasiveness in HCCs. LRP1 offered a possible strategy for tumor molecular therapy.
The role of the cellular protein LRP6 in anthrax toxin entry is controversial. Previous studies showed that LRP6 was important for efficient intoxication of human M2182 prostate carcinoma cells but other studies performed with cells from gene-knockout mice demonstrated no role for either LRP6 or the related LRP5 protein in anthrax toxin entry. One possible explanation for this discrepancy is that LRP6 may be important for anthrax toxin entry into human, but not mouse, cells. To test this idea we have investigated the effect of knocking down LRP6 or LRP5 expression with siRNAs in human HeLa cells. We show here that efficient knockdown of either LRP6, LRP5, or both proteins has no influence on the kinetics of anthrax lethal toxin entry or MEK1 substrate cleavage in these cells. These data argue against a human-specific role for LRP6 in anthrax toxin entry and suggest instead that involvement of this protein may be restricted to certain cell types independently of their species of origin.
Legumain, a novel asparaginyl endopeptidase, has been observed to be highly expressed in several types of tumors, which may play a vital role in carcinogenesis. However, there is no study investigating the relationship among Legumain expression, clinicopathologic, biological variables and patient prognosis in gastric carcinoma.
In this study, a tissue microarray (TMA) containing 282 samples of primary gastric cancer was assessed for Legumain expression by immunohistochemistry. The TMA included 98 lymph node metastasis samples. The protein expression levels of Legumain were evaluated by Western blot analysis.
Cytoplasmic immunoreactivity of Legumain was over-expressed in gastric cancer compared with paired normal gastric mucosa. Increased Legumain levels were significantly correlated with clinical stage, presence of distant metastasis. Legumain was significantly over-expressed in primary gastric cancer with metastasis than without metastasis. Patients with Legumain-positive localized tumors had lower 5-year overall survival (OS) than those with Legumain-negative tumors. Multivariate survival analysis showed that Legumain was an independent prognostic marker for OS (HR 1.459, 95% CI 1.251–1.703, P = 0.007).
Legumain expression could serve as a prognostic biomarker in patients at risk of developing metastasis or recurrence with gastric carcinoma.
AIM: To investigate the expression of distal-less homeobox 2 (DLX2) in gastric adenocarcinoma and its clinicopathological significance.
METHODS: Gastric adenocarcinoma tissues were obtained from gastrectomy specimens of 129 patients from the Department of Surgery and Pathology, the Second Affiliated Hospital of Kunming Medical University. Sixty cases of normal gastric tissues were collected from gastrectomy specimens of adjacent gastric cancer margins greater than 5 cm. Patient diagnosis was established pathologically, and no patient had received chemotherapy or radiotherapy before surgery. All tissue specimens were formalin-fixed and paraffin-embedded. Immunohistochemistry was carried out to investigate the expression of DLX2 in 129 gastric adenocarcinoma tissues and 60 adjacent normal tissues. The immunostaining reaction was semiquantitatively evaluated based on the proportion of positive cells and the median staining intensity in normal gastric epithelial cells or tumor cells. All patients had follow-up records for more than 5 years. Correlations of DLX2 expression with clinicopathological features and prognosis of patients with gastric adenocarcinoma were analyzed. All statistical analyses were performed using the SPSS 17.0 software.
RESULTS: The positive expression of DLX2 was detected in 68 (52.7%) cases of 129 gastric adenocarcinoma tissues and 14 (23.3%) cases of 60 adjacent normal tissues. The difference in DLX2 expression between gastric adenocarcinoma tissues and adjacent normal tissues was statistically significant (χ2 = 14.391, P < 0.001). Moreover, high expression of DLX2 was detected in 48 (37.2%) cases of 129 human gastric cancer tissues, but not in adjacent normal tissues. The expression of DLX2 correlated with the size of tumor (P = 0.001), depth of invasion (P = 0.008), lymph node metastasis (P = 0.023) and tumor-node-metastasis stages (P = 0.020), but was not correlated with age, gender, histological differentiation and distant metastasis. The Kaplan-Meier survival analysis revealed that survival time of patients with high DLX2 expression was significantly shorter than that with low DLX2 expression. However, the multivariate analysis showed that invasion depth (P < 0.001), lymph nodes metastasis (P = 0.001) and distant metastasis (P < 0.001) were independent prognostic factors for patients with gastric adenocarcinoma, but DLX2 expression, tumor location and tumor size were not.
CONCLUSION: These results suggest that increased expression of DLX2 may correlate with the advanced stage of gastric adenocarcinoma, and it may contribute to tumor development.
Gastric adenocarcinoma; Distal-less homeobox 2; Immunohistochemistry; Invasion; Metastasis; Prognosis
Background/aim: Retinoblastoma is the commonest primary intraocular tumour in children. Chemotherapy now plays a big part in the treatment of these tumours. There is not much information about the role of the multidrug resistance proteins (MDR)—P-glycoprotein (P-gp) and vault protein lung resistance protein (LRP)—in retinoblastoma. The authors investigated the expression of P-gp and LRP in retinoblastoma and correlated them clinicopathologically.
Methods: Among 60 retinoblastomas, 40 tumours were not subjected to preoperative or postoperative chemotherapy and 20 tumours were subjected to postoperative chemotherapy. In this cohort 27 tumours had no invasion and 33 tumours had invasion of choroid, optic nerve, and orbit. P-gp and LRP expression were studied by immunohistochemistry. Immunoanalysis was done semiquantitatively.
Results: Among the 60 tumours P-gp was expressed in 23 (38%) tumours and LRP was expressed in 35 (58%). P-gp was expressed in 11/27 (40%) tumours with no invasion and in 12/33 (36%) tumours with invasion. LRP was expressed in 15/27 (55%) tumours with no invasion and in 20/33 (60%) tumours with invasion. Both P-gp and LRP were negative in three tumours with invasion, which had later developed bone marrow metastasis. There was no correlation between P-gp and LRP expression with invasion, differentiation and laterality of the tumours and response to treatment.
Conclusion: Retinoblastoma expresses P-gp and LRP intrinsically before chemotherapy and none of these proteins predicted the response to chemotherapy. Thus, further studies are needed to understand the significance of the expression of the P-gp and LRP proteins in retinoblastoma.
lung resistance protein; P-glycoprtein; multidrug resistance; retinoblastoma; immunohistochemistry; chemotherapy
Changes in the expression of the Notch1 intracellular domain (NICD) and p21 proteins have been shown to be closely associated with the development and progression of a number of cancers. The present study aimed to investigate the expression levels of the two proteins in gastric carcinoma and precancerous lesions, and to determine the clinical significance of this. A total of 109 gastric cancer, 57 precancerous gastric lesion, 50 chronic superficial gastritis and 17 normal gastric mucosa patients were recruited for immunohistochemical staining of NICD and p21 protein expression. The protein expression levels in the gastric cancer patient samples were associated with the clinicopathological and survival data. NICD protein levels were upregulated gradually from normal gastric mucosae through chronic superficial gastritis and precancerous gastric lesions to gastric cancer tissues (P<0.01), whereas p21 protein levels were downregulated accordingly (P<0.01). Increased NICD and a loss of p21 expression were closely associated with tumor dedifferentiation, depth of tumor invasion, lymph node metastasis, surface morphology and Lauren classification in gastric cancer. Thus, NICD expression was inversely associated with p21 expression. In addition, the overall survival rate was greater in NICD− and P21+ patients than in NICD+ and P21− patients, respectively (P<0.05). The COX regression multivariate analysis revealed that NICD+, p21−, depth of tumor invasion and lymph node metastasis were all independent prognostic factors for patients with gastric cancer. NICD and p21 proteins are differentially expressed in gastric cancer and the aberrant expression of these proteins is associated with an advanced tumor stage, tumor metastasis and overall patient survival. Future studies are required to further evaluate the two proteins as novel prognostic markers for patients with gastric cancer.
Notch1 intracellular doman; p21; gastric cancer; prognosis; biomarkers
The aim of this study was to detect metastasis-associated in colon cancer-1 (MACC1) expression in Chinese gastric cancer and analyze the relationship between MACC1 expression and postoperative survival.
The expression of MACC1 and c-MET protein in a sample of 128 gastric cancer tissues was detected by immunohistochemistry. A retrospective cohort study on the prognosis was carried out and data were collected from medical records.
The positive rate of MACC1 protein expression in gastric cancer was 47.66%, higher than that in adjacent noncancerous mucosa (P<0.001). MACC1 protein expression was not related to the clinicopathological variables involved. Kaplan-Meier analysis revealed that the survival of MACC1 positive group tended to be better than that of MACC1 negative group, particularly in patients with stage III carcinoma (P=0.032). Cox regression analysis revealed that MACC1 protein over-expression in gastric cancer tended to be a protective factor with hazard ratio of 0.621 (P=0.057). Immunohistochemical analysis showed that the positive rate of c-MET protein expression was much higher in cases with positive MACC1 expression in gastric cancer (P=0.002), but P53 expression was not associated with MACC1 expression.
MACC1 over-expression implies better survival and may be an independent prognostic factor for gastric cancer in Chinese patients.
MACC1; Gastric cancer; Prognosis
Beclin 1 is a main actor of autophagy. The expression of Beclin 1 and its prognostic role in gastric cancer is largely unexplored. The purpose of the present study is to investigate the expression of beclin 1 in gastric cancer cells, tissues and its relationship with prognosis.
The expression of Beclin 1 was detected in 271 specimens of lymph-node positive gastric cancer patients by immunohistochemistry. The correlation of Beclin 1 expression to clinicopathologic features and survival of gastric cancer was studied. Beclin-1 expression in gastric cancer cell lines and clinical specimens is also detected using reverse transcription-PCR and Western blotting.
Beclin 1 is up-regulated at both mRNA and protein levels in six gastric cancer cell lines compared with those in normal gastric mucosa cell line (GES-1). The expression of Beclin-1 in gastric clinical specimens is also higher than those in the adjacent noncancerous tissues. Of the 271 patients, 229 (84.5%) were Beclin 1 high expression tumors by immunohistochemistry. Beclin 1 expression is closely associated with intravascular embolus. Kaplan-Meier analysis showed high beclin 1 expression was associated with longer overall survival. Both univariate analysis and multivariate analysis revealed that Beclin 1 expression were independent prognostic factors in the patients with node-positive gastric cancer.
Our findings strongly suggest that Beclin 1 has a potential role in tumorigenesis of gastric cancer and could be a promising biomarker for predicting the prognosis of patients with lymph node-positive gastric cancer. It might also serve as a novel therapeutic target for gastric cancer treatment.
The low density lipoprotein receptor–related protein (LRP-1) binds and mediates the endocytosis of multiple ligands, transports the urokinase-type plasminogen activator receptor (uPAR) and other membrane proteins into endosomes, and binds intracellular adaptor proteins involved in cell signaling. In this paper, we show that in murine embryonic fibroblasts (MEFs) and L929 cells, LRP-1 functions as a major regulator of Rac1 activation, and that this activity depends on uPAR. LRP-1–deficient MEFs demonstrated increased Rac1 activation compared with LRP-1–expressing MEFs, and this property was reversed by expressing the VLDL receptor, a member of the same gene family as LRP-1, with overlapping ligand-binding specificity. Neutralizing the activity of LRP-1 with receptor-associated protein (RAP) increased Rac1 activation and cell migration in MEFs and L929 cells. The same parameters were unaffected by RAP in uPAR−/− MEFs, prepared from uPAR gene knockout embryos, and in uPAR-deficient LM-TK− cells. Untreated uPAR+/+ MEFs demonstrated substantially increased Rac1 activation compared with uPAR−/− MEFs. In addition to Rac1, LRP-1 suppressed activation of extracellular signal–regulated kinase (ERK) in MEFs; however, it was Rac1 (and not ERK) that was responsible for the effects of LRP-1 on MEF migration. Thus, LRP-1 regulates two signaling proteins in the same cell (Rac1 and ERK), both of which may impact on cell migration. In uPAR-negative cells, LRP-1 neutralization does not affect Rac1 activation, and other mechanisms by which LRP-1 may regulate cell migration are not unmasked.
urokinase-type plasminogen activator; uPAR; extracellular signal–regulated kinase; cell migration; VLDL receptor
Our hypothesis was that overexpression of certain lipoprotein receptors might be related to lipid accumulation in the human ischemic myocardium. Intramyocardial lipid overload contributes to contractile dysfunction and arrhythmias in cardiomyopathy. Thus, the purpose of this study was to assess the effect of hypercholesterolemic LDL and hypertrigliceridemic VLDL dose on LRP1 expression in cardiomyocytes, as well as the potential correlation between LRP1 expression and neutral lipid accumulation in the left ventricle tissue from ischemic cardiomyopathy patients. Cell culture experiments include control and LRP1-deficient cardiomyocytes exposed to lipoproteins under normoxic and hypoxic conditions. Explanted hearts from 18 ICM patients and eight non-diseased hearts (CNT) were included. Low density lipoprotein receptor-related protein 1 (LRP1), very low density lipoprotein receptor (VLDLR) and low density lipoprotein receptor (LDLR) expression was analyzed by real time PCR and Western blotting. Cholesteryl ester (CE), triglyceride (TG) and free cholesterol (FC) content was assess by thin layer chromatography following lipid extraction. Western blotting experiments showed that protein levels of LRP1, VLDLR and HIF-1α were significantly upregulated in ischemic hearts. Immunohistochemistry and confocal microscopy analysis showed that LRP1 and HIF-1α were upregulated in cardiomyocytes of ICM patients. In vitro studies showed that VLDL, LDL and hypoxia exerted an upregulatory effect on LRP1 expression and that LRP1 played a major role in cholesteryl ester accumulation from lipoproteins in cardiomyocytes. Myocardial CE accumulation strongly correlated with LRP1 levels in ischemic hearts. Taken together, our results suggest that LRP1 upregulation is key for myocardial cholesterol ester accumulation in ischemic human hearts and that LRP1 may be a target to prevent the deleterious effects of myocardial cholesterol accumulation in ischemic cardiomyopathy.
Ischemic cardiomyopathy; LRP1; VLDLR; HIF-1α myocardial lipid accumulation
AIM: To investigate the expression of Popeye domain containing 3 (Popdc3) and its correlation with clinicopathological features and prognosis of gastric cancer.
METHODS: The method of immunohistochemistry was used to investigate the expression of Popdc3 in 306 cases of human gastric cancer and 84 noncancerous gastric tissues. Simultaneously, the relationship between Popdc3 expression and the survival of the patients was retrospectively analyzed.
RESULTS: Popdc3 was detected in 72 (85.71%) of 84 human nontumor mucosa. High expression of Popdc3 protein was detected in 78 (25.49%) of 306 human gastric cancer cases, and low expression was detected in 228 (74.51%). Low expression of Popdc3 correlated with depth of invasion (P < 0.0001), regional lymph nodes (P < 0.0001) and distant metastasis (P = 0.02), and tumor, nodes, metastasis (TNM) stages (P < 0.0001). On multivariate analysis, only the patient’s gender, regional lymph node metastasis, distant metastasis, TNM stages, and the expression of Popdc3 were independent prognostic factors in patients with gastric cancer. The Kaplan-Meier plot showed that low Popdc3 expression had a much more significant effect on the survival of those patients with early-stage tumors (χ2 = 104.741, P < 0.0001), with a > 51.9% reduction in the three-year survival compared with high Popdc3 expression. In late stages, the difference was also significant (χ2 = 5.930, P = 0.015), with a 32.6% reduction in the three-year survival.
CONCLUSION: Reduced expression of Popdc3 may play a significant role in the carcinogenesis and progression of gastric cancer. Popdc3 may be an independent prognostic factor.
Popeye domain containing 3; Gastric cancer; Cell adhesion molecules; Metastasis; Prognosis
Low-density lipoprotein (LDL) receptors are overexpressed in most neoplastic cell lines and provide a mechanism for the internalization and concentration of drug-laden nanoemulsions that bind to these receptors. The aim of the present study was to determine whether the administration of standard chemotherapeutic schemes can alter the expression of LDL and LDL receptor-related protein 1 (LRP-1) receptors in breast carcinoma. Fragments of tumoral and normal breast tissue from 16 consecutive volunteer women with breast cancer in stage II or III were obtained from biopsies before the beginning of neoadjuvant chemotherapy and after chemotherapy, from fragments excised during mastectomy. Tissues were analyzed by immunohistochemistry for both receptors. Because complete response to treatment was achieved in 4 patients, only the tumors from 12 were analyzed. Before chemotherapy, there was overexpression of LDL receptor in the tumoral tissue compared to normal breast tissue in 8 of these patients. LRP-1 receptor overexpression was observed in tumors of 4 patients. After chemotherapy, expression of both receptors decreased in the tumors of 6 patients, increased in 4 and was unchanged in 2. Nonetheless, even when chemotherapy reduced receptors expression, the expression was still above normal. The fact that chemotherapy does not impair LDL receptors expression supports the use of drug carrier systems that target neoplastic cells by the LDL receptor endocytic pathway in patients on conventional chemotherapy.
Breast cancer; Lipoproteins; LDL receptor; LRP-1 receptor; Chemotherapy; Nanoemulsion; Drug delivery
Paxillin encodes a focal adhesion-associated protein and is involved in the progression and aggressive phenotypes of malignancies through its interactions with the actin cytoskeleton and key signal transduction oncogenes. The present study aimed to investigate the clinicopathological and prognostic significance of paxillin in gastric cancer. The expression of paxillin was evaluated using tissue microarrays of gastric adjacent non-cancerous mucosa, adenoma and carcinoma specimens by immunohistochemistry. Paxillin expression was compared against clinicopathological parameters and the survival time of the patients. Paxillin was highly expressed in gastric adenoma compared with that in non-neoplastic mucosa and carcinoma (P<0.05). Paxillin expression was lower in the younger carcinoma patients compared with that in the elder carcinoma patients (P<0.05). Paxillin expression was negatively correlated with tumor size, depth of invasion and lymph node metastasis, but not with patient gender, lymphatic or venous invasion, or TNM staging (P>0.05). Higher paxillin expression was observed in intestinal-type compared with diffuse-type carcinoma (P<0.05). Kaplan-Meier analysis indicated a positive association between paxillin expression and cumulative survival rate in all, advanced and intestinal-type carcinoma patients (P<0.05). Multivariate analysis using the Cox proportional hazards model indicated that patient age, depth of invasion, lymphatic invasion, lymph node metastasis, TNM staging and Lauren classification were independent prognostic factors for all gastric carcinomas (P<0.05). Aberrant paxillin expression may be involved in the growth, invasion, metastasis and differentiation of gastric carcinoma. Altered paxillin expression may, therefore, be employed as an indicator of pathobiological behaviors and prognosis of gastric carcinomas.
gastric carcinoma; tumorgenesis; paxillin; clinicopathological behaviors; prognosis
Lrp (leucine-responsive regulatory protein) is a major Escherichia coli regulatory protein which regulates expression of a number of operons, some negatively and some positively. This work relates to a characterization of lrp, the gene encoding Lrp. Nucleotide sequencing established that the coding regions of lrp and trxB (encoding thioredoxin reductase) are separated by 543 bp and that the two genes are transcribed in opposite directions. In addition, we used primer extension, deletion analyses, and lrp-lacZ transcriptional fusions to delineate the promoter and regulatory region of the lrp operon. The lrp promoter is located 267 nucleotides upstream of the translational start codon of the lrp gene. In comparison with a wild-type strain, expression of the lrp operon was increased about 3-fold in a strain lacking Lrp and decreased about 10-fold in a strain overproducing Lrp. As observed from DNA mobility shift and DNase I footprinting analyses, Lrp binds to one or more sites within the region -80 to -32 relative to the start point of lrp transcription. A mutational analysis indicated that this same region is at least partly required for repression of lrp expression in vivo. These results demonstrate that autogenous regulation of lrp involves Lrp acting directly to cause repression of lrp transcription.