Association of MDR1 genotypes with susceptibility to colorectal cancer in older non-smokers

Objective The multidrug resistance gene 1 (MDR1) seems to play a role in the carcinogenesis of colorectal tumors. The importance of MDR1 SNPs 2677G > T/A in exon 21 and 3435C > T in exon 26 for cancer susceptibility, however, has not yet been clearly defined. Methods Two hundred and eighty-five colorectal cancer patients and 275 controls from five hospitals in the European part of Russia were genotyped for the polymorphisms −129T > C (rs3213619) in exon 1b, 2677G > T/A (rs2032582), and 3435C > T (rs1045642) in this population-based case-control study. Genotype-phenotype analysis was performed with simultaneous consideration of lifestyle risk factors. Results Our analysis confirmed the preponderate impact of smoking on colorectal cancer development. The risk of heavy smokers (≥60 pack years) to develop colorectal cancer by far exceeded that of lifelong non-smokers (OR = 3.9, 95% CI: 1.4 to 10.6). Smoking is a more potent risk factor than is the genetic influence of MDR1 in our study. However, a smoking and age-stratified analysis, revealed a statistically significant association between MDR1 genotypes and colorectal cancer in life-long non-smokers with an age ≥63 years (the median age in our sample). The association was stronger for rectal cancer than for colon cancer. Patients who carried the genotypes (−129TT; 2677GG; 3435CC) or (−129TT; 2677TT; 3435TT) developed more frequently colorectal cancer than others (OR = 3.9; 95% CI: 2.0 to 7.7). Conclusions Our results show that the interaction of genetic and lifestyle risk factors should be taken into account to elucidate the genetic influence of MDR1 variability on cancer susceptibility.     

The PD-1 pathway as a therapeutic target to overcome immune escape mechanisms in cancer

Introduction: Immunotherapy is emerging as a powerful approach in cancer treatment. Preclinical data predicted the antineoplastic effects seen in clinical trials of programmed death-1 (PD-1) pathway inhibitors, as well as their observed toxicities. The results of early clinical trials are extraordinarily promising in several cancer types and have shaped the direction of ongoing and future studies.

Areas covered: This review describes the biological rationale for targeting the PD-1 pathway with monoclonal antibodies for the treatment of cancer as a context for examining the results of early clinical trials. It also surveys the landscape of ongoing clinical trials and discusses their anticipated strengths and limitations.

Expert opinion: PD-1 pathway inhibition represents a new frontier in cancer immunotherapy, which shows clear evidence of activity in various tumor types including NSCLC and melanoma. Ongoing and upcoming trials will examine optimal combinations of these agents, which should further define their role across tumor types. Current limitations include the absence of a reliable companion diagnostic to predict likely responders, as well as lack of data in early-stage cancer when treatment has the potential to increase cure rates.     

Tumor RNA-loaded nanoliposomes increases the anti-tumor immune response in colorectal cancer

PurposeTumor RNA vaccines can activate dendritic cells to generate systemic anti-tumor immune response. However, due to easily degraded of RNA, direct RNA vaccine is less effective. In this study, we optimized the method for preparing PEGylated liposom-polycationic DNA complex (LPD) nanoliposomes, increased encapsulate amount of total RNA derived from CT-26 colorectal cancer cells. Tumor RNA LPD nanoliposomes vaccines improved anti-tumor immune response ability of tumor RNA and can effectively promote anti-tumor therapeutic effect of oxaliplatin.MethodsTotal tumor-derived RNA was extracted from colorectal cancer cells (CT-26 cells), and loaded to our optimized the LPD complex, resulting in the LPD nanoliposomes. We evaluated the characteristics (size, zeta potential, and stability), cytotoxicity, transfection ability, and tumor-growth inhibitory efficacy of LPD nanoliposomes.ResultsThe improved LPD nanoliposomes exhibited a spherical shape, RNA loading efficiency of 9.07%, the average size of 120.37 ± 2.949 nm and zeta potential was 3.34 ± 0.056 mV. Also, the improved LPD nanoliposomes showed high stability at 4 °C, with a low toxicity and high cell transfection efficacy toward CT-26 colorectal cancer cells. Notably, the improved LPD nanoliposomes showed tumor growth inhibition by activating anti-tumor immune response in CT-26 colorectal cancer bearing mice, with mini side effects toward the normal organs of mice. Furthermore, the effect of the improved LPD nanoliposomes in combination with oxaliplatin can be better than that of oxaliplatin alone.ConclusionThe improved LPD nanoliposomes may serve as an effective vaccine to induce antitumor immunity, presenting a new treatment option for colorectal cancer.     

DEPDC1基因在结直肠癌中的表达及其与预后的关系

目的 探讨DEPDC1基因在结直肠癌（CRC）中的表达及其与临床病理特征和预后的关系。方法 以2015年1月至2015年12月中南大学湘雅医学院附属海口医院老年病科和病理科收集的60例CRC病理标本为CRC组（n=60）,相应的癌旁组织为癌旁对照组（n=60）,两组DEPDC1的mRNA和蛋白表达水平采用qRT-PCR和Western blotting技术检测,影响CRC患者预后的因素采用COX比例风险模型分析,预后采用Kaplan-Meier和Log-rank法分析。结果 CRC组DEPDC1的mRNA和蛋白相对表达量均显著高于癌旁对照组（P<0.05）。CRC组DEPDC1高表达患者比例显著高于癌旁对照组（P<0.05）。CRC组织中DEPDC1的表达水平与肿瘤复发显著相关（P<0.05）。DEPDC1表达水平是影响CRC患者5年总体生存率和5年无瘤生存率的独立因素（P<0.05）。CRC组织中DEPDC1低表达患者5年总体生存率、5年无瘤生存率均高于DEPDC1高表达患者（P<0.05）。结论 DEPDC1在CRC组织中高表达,与肿瘤复发有关,DEPDC1高表达的CRC患者预后较差。     

Epigenetics and chemoresistance in colorectal cancer: An opportunity for treatment tailoring and novel therapeutic strategies

Colorectal cancer is the second leading cause of cancer-related deaths in the world. Despite many therapeutic opportunities, prognosis remains dismal for patients with metastatic disease, and a significant portion of early-stage patients develop recurrence after chemotherapy. Epigenetic gene regulation is a major mechanism of cancer initiation and progression, through the inactivation of several tumor suppressor genes. Emerging evidence indicates that epigenetics may also play a key role in the development of chemoresistance. In the present review, we summarize epigenetic mechanisms triggering resistance to three commonly used agents in colorectal cancer: 5-fluorouracil, irinotecan and oxaliplatin. Those epigenetic biomarkers may help stratify colorectal cancer patients and develop a tailored therapeutic approach. In addition, epigenetic modifications are reversible through specific drugs: histone-deacetylase and DNA-methyl-transferase inhibitors. Preclinical studies suggest that these drugs may reverse chemoresistance in colorectal tumors. In conclusion, an epigenetic approach to colorectal cancer chemoresistance may pave the way to personalized treatment and to innovative therapeutic strategies.     

COX-2及nm23-H1在结直肠癌中的表达及其临床意义

目的 探讨环氧化酶2(COX-2)和肿瘤转移抑制基因H1(nm23-H1)在结直肠癌中的表达及其临床意义.方法 应用免疫组化检测COX-2、nm23-H1在62例结直肠癌中的表达.结果 COX-2的高表达与淋巴结转移、Dukes分期和浸润深度有相关性(P＜0.05);nm23-H1的低表达与分化类型、浸润深度、淋巴结转移密切相关(P＜0.05).结论 COX-2和nm23-H1的表达与结直肠癌侵袭转移密切相关,联合检测COX-2和nm23-H1有助于评估病情、判断预后和选择适当治疗手段.     

A phase II study of S-1 plus irinotecan and oxaliplatin in heavily-treated patients with metastatic colorectal cancer

Summary  Three-drug combination of fluoropyrimidine, irinotecan and oxaliplatin has shown survival benefits in patients with metastatic colorectal cancer (mCRC). Recently we performed a phase II study of a new 3-drug regimen, TIROX (S-1 plus irinotecan and oxaliplatin) to evaluate efficacy and safety in refractory mCRC patients. Patients with refractory to all of 3 drugs, age ≥18 years, PS 0–2, ≥1 measurable lesion(s) and adequate organ functions were eligible. S-1 was given 40 mg/m² twice a day on D1–14, oxaliplatin 85 mg/m² and irinotecan 150 mg/m² on D1 every 3 weeks. The primary endpoint was overall response rate (ORR). Between Mar 2007 and Nov 2007, 19 patients (of 18 planned) were enrolled; median age 50 years; M/F 12/7; PS 0/1/2 5/13/1; colon/rectum 11/8. By intent-to-treat analysis, ORR was 21.1% (95% CI, 8.7–43.7) and disease control rate was 52.6% (95% CI 31.5–72.8) with four PRs and six SDs. Median duration of disease control was 4.3 months (95% CI 1.7–6.9). Median PFS was 2.6 months (95% CI 2.2–2.9) and median OS was 9.8 months (95% CI 5.3–14.4) after median F/U of 15.4 months. G3/4 toxicities per pt included neutropenia (five, 26.3%), febrile neutropenia (two, 10.5%), thrombocytopenia (one, 5.3%), diarrhea (two, 10.5%) and fatigue (two, 10.5%). TIROX seemed to be feasible and efficacious for refractory mCRC patients, and could be an alternative for patients with good PS but no further treatment options.     

Th9 cells are subjected to PD-1/PD-L1-mediated inhibition and are capable of promoting CD8 T cell expansion through IL-9R in colorectal cancer

Th9 cells are named after their expression of IL-9. Studies in recent years demonstrated that Th9 cells could contribute to antitumor immunity by enhancing the recruitment and activation of mast cells, natural killer cells, CD8 T cells, and dendritic cells in the tumor microenvironment. To determine whether Th9 cells participate in colorectal cancer (CRC), we collected resected tumor samples from 20 CRC patients. In the tumor-infiltrating lymphocytes (TILs), IL-9⁺IL-4⁻ CD4⁺ T cells could be observed and were present at higher frequencies than the IL-9⁺IL-4⁺ and the IL-9⁻IL-4⁺ cells, suggesting that the majority of IL-9-producing TILs were bona fide Th9 cells. IL-9-secreting TILs presented particularly high PD-1 expression directly ex vivo. The expression of IL-9 was significantly reduced with PD-L1-mediated inhibition, which in turn was suppressed by anti-PD-1 blocking. Interestingly, the circulating CD4⁺ T cell compartment in CRC patients also presented Th9 enrichment, characterized by higher IL-9⁺IL-4⁻ and IL-9⁺IL-4⁺ cell frequencies in the CXCR3⁻CCR6⁻ compartment as compared to that in non-cancer controls. Using exogenous TGF-β and IL-4, we were capable of enriching Th9 cells without concurrent enrichment of Th2 cells. Th9-enriched CD4⁺ T cells, but not Th9-non-enriched cells, significantly increased the expansion of activated CD8⁺ T cells, in a manner that was dependent on the expression of IL-9R. In addition, the frequencies of Th9 cells in the tumor were positively correlated with the frequencies of CD8⁺ TILs. Together, we demonstrated that Th9 cells infiltrated CRC tumor, could be regulated via the PD-1/PD-L1 pathway, and could contribute the CD8⁺ T cell expansion.     

MUC1 plays an essential role in tumor immunity of colorectal cancer stem cell vaccine

Increasing knowledge of colorectal cancer stem cells (CCSCs) and tumor microenvironment improves our understanding of cellular mechanisms involved in the immunity against colorectal cancer (CRC). Tumor associated antigens were evaluated via RNA-seq and bioinformatics analysis, evoking promising targets for tumor immunotherapy. MUC1 has been demonstrated to participate in the maintenance, tumorigenicity, glycosylation and metastasis of CCSCs, which may provide a new priority for CSC vaccination. In the present study, the vaccination with CCSCs with high expression of MUC1 was evaluated in a murine model for the vaccine’s immunogenicity and protective efficacy against CRC. CD133⁺ CCSCs were isolated from SW620 cell line using a magnetic-activated cell sorting system, and shMUC1 was further used to knock down the expression of MUC1 in CD133⁺ CCSCs. Mice were subcutaneously immunized with the cell lysates of CCSCs and shMUC1 CCSCs, followed by a challenge with SW620 cells at ten days after final vaccination. The results indicated CCSC vaccine significantly reduced the tumor growth via a target killing of CCSCs as evidenced by a decrease of CD133⁺ cells and ALDH⁺ cells in tumors. Moreover, CCSC vaccine resulted in the elevated NK cytotoxicity, production of perforin, granzyme B, IFN-γ, memory B cells, and anti-MUC1 antibodies. Of note, MUC1 knockdown partly impaired the anti-tumor efficacy of CCSC vaccine. Importantly, the CCSC vaccine has no toxic damage to organs. Overall, CCSC vaccine could serve as a potent and safe vaccine for CRC treatment, and MUC1 might play an essential role in CCSC vaccine.     

Human acetylator genotype: Relationship to colorectal cancer incidence and arylamine N-acetyltransferase expression in colon cytosol

Polymorphic expression of arylamine N-acetyltransferase (EC 2.3.1.5) may be a differential risk factor in metabolic activation of arylamine carcinogens and susceptibility to cancers related to arylamine exposures. Human epidemiological studies suggest that rapid acetylator phenotype may be associated with higher incidences of colorectal cancer. We used restriction fragment length polymorphism analysis to determine acetylator genotypes of 44 subjects with colorectal cancer and 28 non-cancer subjects of similar ethnic background (i.e., approximately 25% Black and 75% White). The polymorphic N-acetyltransferase gene (NAT2) was amplified by the polymerase chain reaction from DNA templates derived from human colons of colorectal and non-cancer subjects. No significant differences inNAT2 allelic frequencies (i.e., WT, M1, M2, M3 alleles) or in acetylator genotypes were found between the colorectal cancer and non-cancer groups. No significant differences inNAT2 allelic frequencies were observed between Whites and Blacks or between males and females. Cytosolic preparations from the human colons were tested for expression of arylamine N-acetyltransferase activity. Although N-acetyltransferase activity was expressed for each of the arylamines tested (i.e., p-aminobenzoic acid, 4-aminobiphenyl, 2-aminofluorene, -naphthylamine), no correlation was observed between acetylator genotype and expression of human colon arylamine N-acetyltransferase activity. Similarly, no correlation was observed between subject age and expression of human colon arylamine N-acetyltransferase activity. These results suggest that arylamine N-acetyltransferase activity expressed in human colon is catalyzed predominantly by NAT1, an arylamine N-acetyltransferase that is not regulated byNAT2 acetylator genotype. The ability to determine acetylator genotype from DNA derived from human surgical samples should facilitate further epidemiological studies to assess the role of acetylator genotype in various cancers.     

CTHRC1和NFE2L3在结直肠癌组织中的表达及相关性

目的探讨CTHRC1和NFE2L3在结直肠癌早期诊断的意义。方法收集本院2005～2011年经过病理组织学检查诊断结直肠癌的手术标本51例与非癌症的经过病理组织学检查为正常结肠和直肠组织20例,应用免疫组化检测人结直肠中CTHRC1和NFE2L3蛋白的表达情况。结果癌组织中CTHRC1表达阳性47例（92.16%）,正常组织中阳性1例（5.00%）,两组比较差异有统计学意义（χ2=30.13,P〈0.01）;NFE2L3的瘤组织阳性43例（84.43%）,正常组织中6例（30.00%）,两组比较差异有统计学意义（χ2=23.22,P〈0.01）。CTHRC1阳性表达组中,NFE2L3的阳性表达率为72.55%（37/51）;在CTHRC1阴性表达组中,NFE2L3阳性表达率为1.96%（1/51）,差异有统计学意义（χ2=36.54,r：0.510;P〈0.01）,两者表达呈正相关。结论 CTHRC1是结直肠癌发展过程中的重要因素,而NFE2L3可以直接调节CTHRC1基因的表达,这说明通过抑制NFE2L3的活性可以减少CTHRC1的表达,进而延缓结直肠癌的进展,从而发挥其抗肿瘤的作用。     

伊立替康联合5-Fu/亚叶酸钙治疗FOLFOX化疗失败的晚期结直肠癌的疗效

目的评价我国晚期结直肠癌伊立替康联合5-Fu/亚叶酸钙(FOLFIRI方案)治疗FOLFOX化疗失败的临床疗效和毒副反应。方法 FOLFIRI方案二线治疗62例晚期结直肠癌。方法 :伊立替康180 mg/m2,第一天静脉滴注90 min;亚叶酸钙400 mg/m2,第一天滴注2 h;5-Fu 2.6g/m2,亚叶酸钙滴注结束后,立即持续泵入46 h。14 d为一周期,每3周期按RESIST标准评价疗效,所有患者至少接受3周期化疗,最多达12周期。结果 62例患者一共接受346个周期的化疗,所有患者均可评价疗效。部分缓解8例(12.9%),稳定32例(51.6%),总有效率为12.9%。无完全缓解病例。进展22例(35.5%),中位进展时间4.5个月。二线化疗后中位生存时间9.2个月。最常见的不良反应为非血液学毒性,Ⅲ级呕吐反应为6例(9.7%),Ⅲ~Ⅳ级迟发性腹泻为8例(12.9%),3例(4.8%)出现Ⅲ级乙酰胆碱能综合征,13例(20.9%)发生Ⅲ~Ⅳ级粒细胞减少,2例(3.2%)伴发热;无化疗相关性死亡病例。结论 FOLFIRI方案二线治疗FOLFOX化疗失败的晚期结直肠癌疗效确切,不良反应轻。     

早期应用谷氨酰胺治疗对老年结直肠癌病人术后胰岛素抵抗和炎性因子的影响

目的 探讨早期应用谷氨酰胺治疗对老年结直肠癌病人营养指标、术后胰岛素抵抗(IR)、炎性因子和并发症的影响.方法 收集2018年1月至2019年12月东莞市人民医院90例老年结直肠癌病人作为观察对象,采用随机数字表法分为对照组和观察组,每组各45例.所有病人均接受手术治疗.术后,对照组给予常规早期肠内营养治疗,观察组在对...     

Protein kinase inhibitors in metastatic colorectal cancer. Let's pick patients,tumors, and kinase inhibitors to piece the puzzle together!

Introduction: Increased understanding in intracellular signaling pathways leading to carcinogenesis, proliferation, migration, invasion, angiogenesis, and anti-apoptosis of colorectal cancer cells has been critical for target identification and drug development. Specific protein kinase inhibitors (KIs) have been developed to block activated pathways associated with tumor growth and progression. Although showing promising activity in preclinical models, until now, the majority of KIs were not able to demonstrate clinically meaningful efficacy in Phase II/III trials.

Areas covered: The major pathways altered in colorectal cancer will be highlighted, and molecularly defined targets will be discussed. The mechanisms of action and the proof of principle demonstrated in preclinical models of KIs and the disappointing efficacy in clinical trials will be reviewed.

Expert opinion: Despite recent negative study results, KIs have the potential to be the next class of therapeutics in the treatment of metastatic colorectal cancer. Molecular classification of the individual tumors and identification of molecular escape mechanisms for primary (intrinsic) and secondary resistances to KI treatment is critical to select the patients' most likely to benefit. Appropriate drug combinations based on those mechanisms of resistance have to be tested in selected patient populations to ensure progress and efficacy with the goal to lead to a clinically meaningful prolongation of patients' lives.     

单核苷酸多态性与NSCLC铂类化疗敏感性的关系

目的探讨ERCC1(C118T)、XRCC1(G399A)的单核苷酸多态性(SNP)与非小细胞肺癌(NSCLC)对铂类为主化疗方案敏感性的关系。方法经病理学确诊的晚期NSCLC患者120例,采用铂类为主的两药联合化疗方案,2～3个周期后进行临床疗效评价。根据cDNA芯片原理制作目的基因芯片,利用双色荧光探针杂交进行ERCC1、XRCC1的多态性的基因分型,比较不同基因型与化疗敏感性的关系。结果 ERCC1(C118T)至少携带1个T等位基因型的患者化疗有效率为44.7%,显著高于C/C基因型的19.2%(P<0.05);携带XRCC1(G399A)G/G基因型者化疗有效率为43.8%,高于至少携带1个A等位基因的19.4%(P<0.05)。结论 ERCC1、XRCC1基因多态性与NSCLC患者对铂类药物化疗的敏感性相关。     

The use of chitosan-coated flexible liposomes as a remarkable carrier to enhance the antitumor efficacy of 5-fluorouracil against colorectal cancer

Surface-coated nanocarriers have been extensively used to enhance the delivery of anticancer drugs and improve their therapeutic index. In this study, chitosan (CS)-coated flexible liposomes (chitosomes) containing 5-fluorouracil (5-FU) were designed and characterized for use as a novel approach to target colon cancer cells. 5-FU-loaded flexible liposomes (F1, F2, and F3) and 5-FU-loaded chitosomes (F4, F5, and F6) were prepared using film hydration and electrostatic deposition techniques, respectively. The particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE%), morphology, and in vitro drug release ability, and cytotoxicity of the formulations were determined. The results revealed that the size of chitosomes ranged from 212 to 271 nm with a positive surface charge of 6.1 to 14.7 mV, whereas the particle size of liposomes ranged from 108 to 234 nm with negative surface charges of ?2.3 to ?16.3. F3 and F6 had a spherical shape with a rough surface structure. The in vitro drug release study revealed that chitosomes retard 5-FU release as opposed to the 5-FU solution and liposomes. The cytotoxicity study using a colon cancer cell line (HT-29) showed that 5-FU-loaded chitosomes were more effective in killing cancer cells in a sustained manner than liposomes and the 5-FU solution. Chitosomes were therefore successfully developed as nanocarriers of 5-FU, with potential cytotoxicity for colorectal cancer cells.     

Regulation of gamma-H2AX and securin contribute to apoptosis by oxaliplatin via a p38 mitogen-activated protein kinase-dependent pathway in human colorectal cancer cells

Oxaliplatin, a chemotherapeutic drug, induces DNA strand breaks leading to apoptosis in colorectal cancer cells. gamma-H2AX is a phosphorylated histone H2AX that can act as a marker of DNA double-strand breaks (DSBs). It has been shown that securin proteins were over-expressed in a variety of cancer cells. However, the roles of gamma-H2AX and securin on the oxaliplatin-induced apoptosis in human colorectal cancer cells remain unclear. Treatment of oxaliplatin (1-10muM for 6-24h) persistently induced gamma-H2AX formation and inhibited securin protein expression via a time- and concentration-dependent manner in HCT116 securin-wild type colorectal cancer cells. Compared with HCT116 securin-wild type cells, the induction of apoptosis and persistent gamma-H2AX formation by oxaliplatin was reduced in the HCT116 securin-null colorectal cancer cells. Furthermore, the blockage of caspases by specific caspase inhibitors reduced the levels of gamma-H2AX proteins and cytotoxicity but increased securin protein expression in the oxaliplatin-exposed cells. The gene knockdown of H2AX by transfection with a short interfering RNA of H2AX enhanced the oxaliplatin-induced cell death. Interestingly, the phosphorylation of p38 mitogen-activated protein kinase (MAPK) was markedly increased by oxaliplatin. Pre-treatment of a specific p38 MAPK inhibitor SB202190 reduced gamma-H2AX proteins and increased securin protein expression in the oxaliplatin-treated cells. Our findings suggest that p38 MAPK may oppositely regulate securin protein expression and gamma-H2AX formation in the oxaliplatin-induced apoptosis of human colorectal cancer cells.     

Autophagy inhibition switches low-dose camptothecin-induced premature senescence to apoptosis in human colorectal cancer cells

Recently, several studies indicated that senescent tumor cells are resistant to apoptosis in chemotherapy. They may return to cell cycle, thus act as stumbling blocks in anticancer treatments. In the present study, we found that, in human colorectal cancer cells, low-dose camptothecin (CPT) simultaneously induced autophagy and premature senescence through AMPK-TSC2-mTOR pathway and ATM-Chk2-p53-p21 pathway respectively. What's important is the suppression of autophagy substantially increased apoptosis and greatly attenuated senescence possibly by blocking p53/p21 pathway, which suggests that autophagy plays an indispensable role in sustaining cell senescence caused by low-dose CPT. The combination of low-dose CPT and autophagy inhibitor, a way to lead senescent cells to die, would be potentially valuable in cancer therapy.