Prognostic significance of lymphovascular invasion in colorectal cancer and its association with genomic alterations

BACKGROUND Lymphovascular invasion (LVI) is suggested to be an early and important step in tumor progression toward metastasis, but its prognostic value and genetic mechanisms in colorectal cancer (CRC) have not been well investigated. AIM To investigate the prognostic value of LVI in CRC and identify the associated genomic alterations. METHODS We performed a retrospective analysis of 1219 CRC patients and evaluated the prognostic value of LVI for overall survival by the Kaplan-Meier method and multivariate Cox regression analysis. We also performed an array-based comparative genomic hybridization analysis of 47 fresh CRC samples to examine the genomic alterations associated with LVI. A decision tree model was applied to identify special DNA copy number alterations (DCNAs) for differentiating between CRCs with and without LVI. Functional enrichment and protein-protein interaction network analyses were conducted to explore the potential molecular mechanisms of LVI. RESULTS LVI was detected in 150 (12.3%) of 1219 CRCs, and the presence was positively associated with higher histological grade and advanced tumor stage (both P < 0.001). Compared with the non-LVI group, the LVI group showed a 1.77-fold (95% confidence interval: 1.40-2.25, P < 0.001) increased risk of death and a significantly lower 5-year overall survival rate (P < 0.001). Based on the comparative genomic hybridization data, 184 DCNAs (105 gains and 79 losses) were identified to be significantly related to LVI (P < 0.05), and the majority were located at 22q, 17q, 10q, and 6q. We further constructed a decision tree classifier including seven special DCNAs, which could distinguish CRCs with LVI from those without it at an accuracy of 95.7%. Functional enrichment and proteinprotein interaction network analyses revealed that the genomic alterations related to LVI were correlated with inflammation, epithelial-mesenchymal transition, angiogenesis, and matrix remodeling. CONCLUSION LVI is an independent predictor for survival in CRC, and its development may correlate with inflammation, epithelial-mesenchymal transition, angiogenesis, and matrix remodeling.     

p53 expression and resistance against paclitaxel in patients with metastatic breast cancer

PURPOSE: Paclitaxel is an important agent in the pharmacological treatment of metastatic breast cancer. Despite its efficacy in selected patients, the majority of patients have a resistance against paclitaxel. The aim of this study was to identify the responding patients and hence prevent the other patients from ineffective treatment. Identifying these patients could spare them an ineffective treatment and could in turn characterize a subgroup of patients with a higher response rate. MATERIAL AND METHODS: Thirty-three patients with metastatic breast cancer received paclitaxel 175 mg/m(2 )either as first- (15 patients) or as second-line (18 patients) treatment. Immunohistochemistry was performed on the blocks of the primary tumors with monoclonal antibodies against p53, HER-2/ neu, P-glycoprotein, Glutathione-S-Transferase-pi, and beta-tubulin II. The expression of those factors was then correlated with the objective response to paclitaxel. RESULTS: Ten of 33 patients had an objective response to treatment. A significant correlation with the objective response was found for the expression of p53. None of the tumors with p53 expression ( n=11) responded to paclitaxel. In contrast, 10 of the 22 patients without p53 expression showed an objective response ( P=0.013). Expression of HER-2/ neu, P-glycoprotein, Glutathione-S-Transferase-pi, and beta-tubulin II did not show a correlation with the response to paclitaxel. CONCLUSION: The immunohistochemical detection of p53 characterizes patients with metastatic breast cancer unlikely to respond to paclitaxel.     

miR-126在人结肠癌细胞中的表达及其对结肠癌细胞耐药性的影响

目的探讨miR-126在人结肠癌细胞中的表达及其对结肠癌细胞的耐药性影响。方法采集我院肿瘤科2010年7月至2013年8月收治的45例结肠癌患者的癌组织、癌旁组织及30例同期体检健康对象的正常结肠组织(正常组织),采用荧光PCR检测miR-126表达水平;体外培养HCT116细胞,通过转染抑制序列抑制miR-126的表达,检测抑制HCT116细胞miR-126的表达对结肠癌细胞耐药性的影响。结果结肠癌组织的miR-126阳性表达率显著低于癌旁组织、正常组织(P0.05);癌旁组织的miR-126阳性表达率低于正常组织但差异不显著(P0.05);miR-126表达在年龄、性别、分化程度、肿瘤大小间差异不显著(P0.05),不具统计学意义;miR-126表达与淋巴结转移、Dukes分期、临床分期具有显著的相关性,且miR-126表达水平在各个层之间差异显著(P0.05);在0、5、10、20 mg/L的奥沙利铂培养基中,miR-126阳性组的癌细胞活性(吸光度值)均显著低于miR-126阴性组且差异具有统计学意义(P0.05)。结论结肠癌组织中的miR-126阳性表达率较低,癌细胞组织中的miR-126阳性表达有利于降低癌细胞的耐药性,有利于对结肠癌的治疗效果。     

Mechanisms of drug resistance in colon cancer and its therapeutic strategies

Drug resistance develops in nearly all patients with colon cancer, leading to a decrease in the therapeutic efficacies of anticancer agents. This review provides an up-to-date summary on over-expression of ATPbinding cassette(ABC) transporters and evasion of apoptosis, two representatives of transport-based and non-transport-based mechanisms of drug resistance, as well as their therapeutic strategies. Different ABC transporters were found to be up-regulated in colon cancer, which can facilitate the efflux of anticancer drugs out of cancer cells and decrease their therapeutic effects. Inhibition of ABC transporters by suppressing their protein expressions or co-administration of modulators has been proven as an effective approach to sensitize drug-resistant cancer cells to anticancer drugs in vitro. On the other hand, evasion of apoptosis observed in drug-resistant cancers also results in drug resistance to anticancer agents, especially to apoptosis inducers. Restoration of apoptotic signals by BH3 mimetics or epidermal growth factor receptor inhibitors and inhibition of cancer cell growth by alternative cell death pathways, such as autophagy, are effective means to treat such resistant cancer types. Given that the drug resistance mechanisms are different among colon cancer patients and may change even in a single patient at different stages, personalized and specific combination therapy is proposed to be more effective and safer for the reversal of drug resistance in clinics.     

Markers of drug resistance in relapsing colon cancer

PURPOSE: 5-Fluorouracil failure and drug resistance, which often occurs during chemotherapy, is still a great obstacle to the success of human colon cancer treatment. Thus, the comparative study of markers of drug resistance in cancer cells before and after chemotherapy may be extremely helpful in the selection of the appropriate chemotherapeutic drug in colon cancer patients who fail adjuvant treatment with 5-fluorouracil. In the present study we examined the differential expression of three multidrug resistance-related proteins (i.e., P-glycoprotein, MRP, and LRP) and of topoisomerase IIalpha in a series of 20 primary colon carcinomas and their recurrences. METHODS: All markers were determined at tissue level by three-step immunohistochemistry using appropriate monoclonal antibodies, and the markers' immunopositivity was quantified by image analysis. In addition, Feulgen stain was used for the assessment of nuclear DNA content of malignant cells at their primary location. RESULTS: Some degree of aneuploidy was detected in all primary carcinomas. The immunoexpression of the three multidrug resistance-related proteins did not change significantly, either qualitatively (positivity vs negativity) or quantitatively, after chemotherapy. On the contrary, the percentages of topoisomerase IIalpha-positive malignant cells were significantly increased in the tumour recurrences by comparison to their primary locations ( P=0.011). CONCLUSIONS: According to our results, increased topoisomerase IIalpha immunohistochemical expression appears to be part of the malignant cells' phenotype in recurrent colon cancers. Therapeutic options after failure of 5-fluorouracil-based treatment could therefore include appropriate topoisomerase IIalpha-targeted drugs.     

Folic acid and its metabolites modulate IGF-I receptor gene expression in colon cancer cells in a p53-dependent manner

The insulin-like growth factor-I receptor (IGF-IR) has an important role in colorectal cancer development and progression. IGF-IR displays a potent anti-apoptotic activity and is overexpressed in primary tumors and colon cancer-derived cell lines. Folic acid, a member of the vitamin B family, is a chemopreventive agent whose deficiency has been linked to an enhanced colon cancer risk. The present study was aimed at testing the hypothesis that part of the modulatory effect of folic acid on malignant transformation may be attributed to its ability to regulate IGF-IR gene expression. Regulation of IGF-IR gene expression by folic acid was assessed using western blots, RT-PCR, transient transfections and chromatin immunoprecipitation assays. Activation of the IGF-IR signaling pathway was evaluated by measuring phosphorylation of ERK, and apoptosis was assayed using poly (ADP-ribose) polymerase cleavage and annexin V-FITC staining. Results obtained showed that folic acid induced a dose-dependent decrease in IGF-IR protein and mRNA levels in the HCT116 +/+ colon cancer cell line. This effect was associated with a significant reduction in IGF-IR promoter activity. Similar effects were elicited by the folic acid metabolites dihydrofolic acid and tetrahydrofolic acid. In addition, folic acid abrogated the IGF-I-stimulated phosphorylation of the downstream signaling molecule ERK1/2 and exhibited a pro-apoptotic activity. Moreover, folic acid induced a significant decrease in Sp1 binding to the IGF-IR promoter region. Finally, folic acid had no effect in wild-type p53-depleted HCT116 -/- and Caco-2 cells. In conclusion, the mechanism of action of folic acid involves regulation of IGF-IR gene expression. The ability of folic acid to downregulate the IGF-I signal transduction pathway may allow the micronutrient to function as a chemopreventive agent. Folic acid deficiency, on the other hand, may lead to increased IGF-IR gene expression, with ensuing pathological activation by endocrine and/or autocrine/paracrine IGF-I.     

肺癌组织p53基因突变与肿瘤耐药基因表达的相关性及其临床意义

目的探讨p53基因突变与肿瘤耐药基因表达状况及肺癌耐药的关系。方法应用免疫组织化学法检测66例肺癌及其癌旁组织的突变型P53蛋白及耐药相关蛋白的表达水平。其中31例肺癌及其癌旁组织应用聚合酶链测定单链构象多态性(PCRSSCP)银染法及逆转录聚合酶链测定(RTPCR)法检测p53基因第5～8外显子突变情况及各种耐药基因的mRNA表达水平;12例应用三磷酸腺苷肿瘤化疗敏感实验(ATPTCA)检测肺癌细胞对诺维本、卡铂、依托泊苷、表柔比星、5氟尿嘧啶、博莱霉素的敏感性。结果突变型P53蛋白与P糖蛋白(Pgp)、多药耐药相关蛋白(MRP1)、谷胱甘肽S转移酶π(GSTπ)的表达状况存在着相关性(r分别为047、033、044,P均<005);ATPTCA结果显示突变型P53蛋白的表达状况及其与Pgp、MRP的共表达均和诺维本及卡铂的耐药相关(P均<005)。结论肺癌组织耐药相关蛋白的表达与p53基因突变有关,突变型P53蛋白的检出可以预示内源性耐药的存在,恢复野生型P53蛋白的功能可能有助于逆转耐药。     

p53 and breast cancer, an update

p53 plays a key role in mediating cell response to various stresses, mainly by inducing or repressing a number of genes involved in cell cycle arrest, senescence, apoptosis, DNA repair, and angiogenesis. According to this important function, p53 activity is controlled in a very complex manner, including several auto-regulatory loops, through the intervention of dozens of modulator proteins (the 'p53 interactome'). p53 mutations are observed in a significant minority of breast tumours. In the remaining cases, alterations of interactome components or target genes could contribute, to some extent, to reduce the ability of p53 to efficiently manage stress events. While the prognostic and predictive value of p53 is still debated, there is an increasing interest for p53-based therapies. The present paper aims to provide updated information on p53 regulation and function, with specific interest on its role in breast cancer.     

p53 autoantibodies in sera of patients with a colorectal cancer and their association to p53 protein concentration and p53 immunohistochemistry in tumor tissue

We evaluated p53 autoantibodies (p53-Ab) as a preoperative tumor marker and as a prognosis marker. We also investigated whether p53-Ab production is dependent on p53 protein overexpression in tumor tissue or on tumor volume. Serum samples of patients with a colorectal cancer (n = 130) and of healthy controls (n = 44) were examined for p53-Ab using an ELISA kit. P53 protein expression in tumor tissue was demonstrated immunohistochemically and quantified by ELISA. Tumor volume was calculated and patients' survival computed using the Kaplan-Meier method. p53-Ab were detected in the serum from 15% of patients; all controls were negative. There was a significant correlation between p53-Ab production and positive immunostaining or p53 protein concentration in tumor tissue. p53-Ab were detected at a higher percentage of patients with a tumor volume of 10 cm3 or greater than in those with a smaller tumor. No difference in patients' prognosis was found between the p53-Ab positive and negative groups. Because of their low sensitivity (15%) p53-Ab are not suitable as a preoperative tumor marker. However, their high specificity (100%) and their potential for early diagnosis of a tumor relapse makes them valuable for postoperative monitoring during follow-up in p53-Ab positive patients. Furthermore, their detection can be used as a simple serological test for early detection of p53 alterations.     

结肠肿瘤PTHrP的表达及其与P53蛋白表达关系的研究

目的 研究ＰＴＨｒＰ在肿瘤发生过程中的作用以及ＰＴＨｒＰ和Ｐ５３在结肠腺中表达的关系。方法 用免疫组织化学ＡＢＣ法对６８例结肠组织（３０例结肠腺癌,２０例腺瘤性息肉,１８例正常结肠组织）进行ＰＴＨｒＰ检测,并对其中３０例结肠腺癌进行Ｐ５３检测。结果 结肠癌组ＰＴＨｒＰ的阳性率明显高于腺瘤组（Ｐ〈０．０５）和正常组（Ｐ〈０．０５）。绫 ＰＴＨｒＰ的过度表达与细胞的恶性 经有关,与肿瘤分化程度无明显关     

联合应用p38MAPK抑制剂对降低结肠癌阿霉素耐药性的影响

目的:探讨p38 MAPK抑制剂通过Akt(蛋白激酶B)有关的信号途径对结肠癌细胞阿霉素(Doxorubicin)化疗敏感性的影响.方法:应用阿霉素(Dox)和p38 MAPK特异性抑制剂SB203580及两者联合应用去处理结肠癌HCT-116细胞株.采用MTT[3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐]法检测化疗药物对肿瘤细胞的生存抑制率,Western blot蛋白免疫印迹技术检测化疗药物处理后癌细胞Akt和磷酸化Akt的表达水平.结果:MTT显示阿霉素和抑制剂SB203580对结肠癌细胞均有抑制作用(26.60%,33.87%),后者大于前者,两者相同用量联合后癌细胞抑制率更明显(56.04%).Western blot显带说明阿霉素处理组较联合组的Akt表达水平并无明显差异,而磷酸化的Akt水平较SB203580组和联合组显著升高.亦即抑制剂组和联合组方案可降低结肠癌细胞磷酸化Akt的表达水平.结论:p38 MAPK抑制剂SB203580可能通过阻断P13K/Akt信号途径或其他有关Akt的通路以提高结肠癌细胞阿霉素化疗的敏感性.     

结肠癌组织中整合素α3的表达与侵袭转移性的关系

目的:探讨整合素α3在结肠癌组织中表达的临床病理学意义.方法:手术切除病理学诊断的结肠癌标本80例(男47例,女33例)及淋巴结60枚,淋巴结转移灶40枚和未转移淋巴结20枚.非肿瘤结肠黏膜组织12例作对照.采用免疫组化方法检测整合素α3的表达情况.结果:结肠癌原发灶及淋巴结转移灶中α3亚单位整合素的染色特征发生明显改变,表达程度明显弱于邻近非肿瘤结肠黏膜组和未转移淋巴结(52/80vs12/12,24/40vs18/20,P＜0.05).其表达与患者性别和年龄无关.但随肿瘤Dukes分期增加及癌组织分化程度降低其表达逐渐减弱.此外,在发现有淋巴结转移与肝转移病例中,其原发灶整合素α3表达弱于无淋巴结转移与无肝转移病例(25/49vs27/31,1/16vs 51/64,/P＜0.05).结论:整合素α3与结肠癌淋巴结转移程度和病期等生物学行为密切相关.     

Expression of maspin in colon cancers: its relationship with p53 expression and microvessel density

We studied the expression of maspin in colonic adenocarcinoma compared with adenoma and metastatic adenocarcinoma as well as the relationship with its possible regulator, p53. The colonic specimens consisted of 24 adenomas, 49 adenocarcinomas, and 17 metastatic adenocarcinomas. Immunohistochemical staining of paraffin sections was done with microwave-based antigen retrieval methods. The Ki-67 index and the microvessel density were counted using an image analysis system. Maspin expression was positive in 75.5% of adenocarcinomas and 91.7% of adenomas. Only 47.1% of the nodal metastasis showed positive maspin expression. In colonic adenocarcinomas, p53 expression was positive in 44.7% of the maspin-positive groups compared with 100% of the maspin-negative groups (P < 0.005). Colonic adenocarcinomas with the positive maspin expression groups showed less intense microvessel density (181.1 ± 54.2) than those of the negative maspin expression groups (256.1 ± 75.4, P < 0.001). In conclusion, we demonstrated maspin expression in colon cancer with a sequential decreased expression rate from adenoma to metastatic carcinomas, which signifies the tumor suppressive function of maspin, and an inverse correlation with p53 and microvesel density, which indicates the regulatory effect of p53 on maspin and anti-angiogenesis effect of maspin.     

p53 codon 72 polymorphism in Taiwanese breast cancer patients

There are clear discrepancies between ethnicity and geographic area regarding the peak age incidence and mortality of breast cancer. Underlying variances include genetic, environmental, and socioeconomic factors. The wild-type p53 codon has two common polymorphic variants from a single-base-pair substitution at codon 72, where either C-C-C encodes proline (p53-p72) or C-G-C encodes arginine (p53-R72). We aim to study the p53 codon 72 genotypes of patients with breast cancer in Taiwan and make a comparison with the published data to ascertain whether any difference exists between Taiwanese and Western patients with breast cancer. We also evaluated the effect of the p53 codon 72 polymorphism on clinicopathologic features. We examined blood from 170 Taiwanese women with breast cancer with polymerase chain reaction–restriction fragment length polymorphism for the genotypes of p53 codon 72. For the p53 codon 72 polymorphism, there were 31 p53-P/P72 (18.2%), 93 p53-R/P72 (54.7%), and 46 p53-R/R72 (27.1%) with the allele frequencies 0.54 for the p53-R72 and 0.46 for p53-P72, respectively. Our results indicate that there was more p53-P72 (40.6% in Asians vs. 26.4% in Caucasians) and twice the incidence of p53-P/P72 homozygotes (18% in Asians vs. 8% in Caucasians) among the Asian population. Patients with the p53-R/R72 variant were more likely to have a t1 tumor size status (55.2%) compared with patients with the P53-P/R72 (30.9%) or P53-P/P72 variant (36%). Our results support the hypothesis that genetic factors may contribute to the difference between Taiwanese or Asian breast cancer and Western breast cancer patient populations.