Addition of integrin binding sequence to a mutant human endostatin improves inhibition of tumor growth

Tumor vasculatures express high levels of alphaVbeta3/alphaVbeta5 and alpha5beta1 integrins. Consequently, peptides containing the RGD (Arg-Gly-Asp) sequence, which is present in ligands of integrins, is effective in targeting therapeutic reagents to tumor vascular endothelium. In our study, we investigated whether the biologic activity of endostatin can be enhanced by the addition of an integrin targeting sequence. RGD sequence was added to either the amino or carboxyl terminus of endostatin containing a point mutation, P125A-endostatin. Earlier we have shown that the P125A mutation did not affect the biologic activity of endostatin but in fact had better antiangiogenic activity when compared to the native molecule. Further modification of P125A-endostatin with the RGD motif showed specific and increased binding to endothelial cells, and the increased binding coincided with improved antiangiogenic properties. Both amino and carboxyl terminal RGD-modification of P125A-endostatin resulted in greater inhibition of endothelial cell migration and proliferation. RGD modification increased tumor localization without affecting the circulatory half-life of P125A-endostatin, and RGD-modified P125A-endostatin was found to be more effective when compared to the P125A-endostatin in inhibiting ovarian and colon cancer growth in athymic mice. Complete inhibition of ovarian tumor growth was observed when P125A-endostatin-RGD was encapsulated into alginate beads. These studies demonstrate that addition of a vascular targeting sequence can enhance the biologic activity of an antiangiogenic molecule.     

Binding of endostatin to human ovarian cancer cells inhibits cell attachment

Endostatin, a C-terminal fragment of collagen type XVIII, is one of the well-characterized endogenous inhibitors of angiogenesis. Endostatin is known to bind integrin alpha(5)beta(1), which is upregulated on tumor endothelium. Most of the ovarian cancer cells express significant amounts of alpha(5)beta(1) integrin, which is important for ovarian cancer cells to attach to the peritoneal wall. Therefore we investigated whether endostatin could directly bind ovarian cancer cells and inhibit tumor cell attachment to extracellular matrix. Binding of endostatin to ovarian cancer cells was characterized by preincubation with function blocking antibodies to integrin subunits. These studies showed that ovarian cancer cell attachment to fibronectin-coated wells can be inhibited by alpha(5)beta(1) integrin specific antibodies as well as endostatin. Downregulation of integrin alpha(5) and beta(1) by siRNA abrogated the binding of OVCAR5 and human umbilical vein endothelial cell to endostatin. Although endostatin treatment did not affect ovarian cancer cell migration, treated cells failed to attach mouse peritoneal wall preparations. These studies suggest an extra-antiangiogenic role for endostatin, which can be used prevent peritoneal attachment and dissemination of ovarian cancer cells.     

Expression pattern and circulating levels of endostatin in patients with pancreas cancer

Endostatin is a potent inhibitor of angiogenesis that is cleaved from the basement membrane protein type XVIII collagen. Expression of endostatin has recently been shown by Western blot analysis of tissue lysates in normal pancreas and pancreas cancer tissue. We show here that the expression pattern of type XVIII collagen/endostatin is shifted from a general basement membrane staining and is mainly located in the vasculature during tumor progression. This shift in type XVIII collagen/endostatin expression pattern coincides with an up-regulation of MMPs involved in endostatin processing in the tumor microenvironment, such as MMP-3, MMP-9 and MMP-13. The circulating levels of endostatin was analyzed in patients with pancreas cancer and compared to that of healthy controls, as well as after surgical treatment or in a group of nonoperable patients after intraperitoneal fluorouracil (5-FU) chemotherapy. The results show that patients with pancreas cancer have increased circulating levels of endostatin and that these levels are normalized after surgery or intraperitoneal chemotherapy. These findings indicate that endostatin could be used as a biomarker for pancreas cancer progression.     

Inhibition of the mammary carcinoma angiogenic switch in C3(1)/SV40 transgenic mice by a mutated form of human endostatin

Cancer therapies based on the inhibition of angiogenesis by endostatin have recently been developed. We demonstrate that a mutated form of human endostatin (P125A) can inhibit the angiogenic switch in the C3(1)/Tag mammary cancer model. P125A has a stronger growth-inhibitory effect on endothelial cell proliferation than wild-type endostatin. We characterize the angiogenic switch, which occurs during the transition from preinvasive lesions to invasive carcinoma in this model, and which is accompanied by a significant increase in total protein levels of vascular endothelial growth factor (VEGF) and an invasion of blood vessels. Expression of the VEGF(188) mRNA isoform, however, is suppressed in invasive carcinomas. The VEGF receptors fetal liver kinase-1 (Flk-1) and Fms-like tyrosine kinase-1 (Flt-1) become highly expressed in epithelial tumor and endothelial cells in the mammary carcinomas, suggesting a potential autocrine effect for VEGF on tumor cell growth. Angiopoietin-2 mRNA levels are also increased during tumor progression. CD-31 (platelet-endothelial cell adhesion molecule [PECAM]) staining revealed that blood vessels developed in tumors larger than 1 mm The administration of P125A human endostatin in C3(1)/Tag females resulted in a significant delay in tumor onset, decreased tumor multiplicity and tumor burden and prolonged survival of the animals. Endostatin treatment did not reduce the number of preinvasive lesions, proliferation rates or apoptotic index, compared with controls. However, mRNA levels of a variety of proangiogenic factors (VEGF, VEGF receptors Flk-1 and Flt-1, angiopoietin-2, Tie-1, cadherin-5 and PECAM) were significantly decreased in the endostatin-treated group compared with controls. These results demonstrate that P125A endostatin inhibits the angiogenic switch during mammary gland adenocarcinoma tumor progression in the C3(1)/Tag transgenic model.     

Inhibition of ovarian cancer by RGD-P125A-endostatin-Fc fusion proteins

Previous studies have shown that a single point mutation in endostatin at position 125 (P125A) can improve the biological activity of endostatin. Addition of an integrin-targeting moiety, R-G-D, resulted in better localization to tumor vasculature and improved the antiangiogenic activity of endostatin. Because endostatin has relatively shorter serum half-life, frequent dosing was required for inhibiting tumor growth. In our study, we have genetically fused RGD-P125A-endostatin to Fc of IgG4 isotype and evaluated its antiangiogenic and antitumor effects in athymic mice. Two genetic constructs were made, RGD-P125A-endostatin-Fc (RE-Fc) and P125A-endostatin-RGD-Fc (ER-Fc). Both constructs were cloned and expressed in mammalian cells. Purified fusion proteins inhibited endothelial cell migration and proliferation better than yeast-derived P125A-endostatin. Both RE-Fc and ER-Fc inhibited ovarian cancer growth and were found to be as effective as Bevacizumab treatment. Fusion protein showed marked increased half-life. Combination treatment with Bevacizumab and ER-Fc showed additive inhibition of ovarian cancer growth. These studies demonstrate that genetic fusion with human IgG4-Fc increases the half-life of P125A-endostatin and can be used along with Bevacizumab to improve antiangiogenic and antitumor activities.     

Human endostatin inhibits growth of human non-small-cell lung cancer in a murine xenotransplant model.

Overall prognosis in human NSCLC remains poor. Antiangiogenic treatment has become a promising concept for the treatment of solid malignancies. Our purpose was to evaluate the efficacy of recombinant HSENDO for the treatment of human NSCLC in an orthotopic murine xenotransplantation model. The efficacy of HSENDO was tested in vitro in cell-proliferation, cell-migration and tube-formation assays. In vivo, the effect of HSENDO on tumor growth was tested in s.c. xenotransplanted human NSCLC and on intrapulmonary induced human NSCLC. In vitro, HSENDO inhibited both human and rodent endothelial cell proliferation in a time- and dose-dependent fashion. Endothelial cell migration was inhibited by 97%. Tube formation of murine endothelial cells was inhibited and preexisting tubes degenerated after HSENDO exposure. In vivo, HSENDO delayed growth of s.c. xenotransplanted tumors. Immunohistochemic staining demonstrated no change in microvessel density but a significant reduction of proliferating tumor cells and an increase in bFGF and VEGF expression, reflecting the antiangiogenic effect of HSENDO. Intrapulmonary tumor induction caused death subsequent to metastatic disease. Systemic HSENDO application extended survival significantly. HSENDO was demonstrated to inhibit endothelial cell proliferation, migration and tube formation effectively. In vivo growth of s.c. transplanted tumors was delayed and survival extended by 32% and 69%, respectively, after intrapulmonary NSCLC induction.     

Mutation analysis of EP300 in colon,breast and ovarian carcinomas

The putative tumour suppressor gene EP300 is located on chromosome 22q13 which is a region showing frequent loss of heterozygosity (LOH) in colon, breast and ovarian cancers. We analysed 203 human breast, colon and ovarian primary tumours and cell lines for somatic mutations in EP300. LOH across the EP300 locus was detected in 38% of colon, 36% of breast, and 49% of ovarian primary tumours but no somatic mutations in EP300 were identified in any primary tumour. Analysis of 17 colon, 11 breast, and 11 ovarian cancer cell lines identified truncating mutations in 4 colon cancer cell lines (HCT116, HT29, LIM2405 and LIM2412). We confirmed the presence of a previously reported frameshift mutation in HCT116 at codon 1699 and identified a second frameshift mutation at codon 1468. Bi-allelic inactivation of EP300 was also detected in LIM2405 that harbours an insC mutation at codon 927 as well an insA mutation at codon 1468. An insA mutation at codon 1468 was identified in HT29 and a CGA>TGA mutation at codon 86 was identified in LIM2412. Both these lines were heterozygous across the EP300 locus and western blot analysis confirmed the presence of an apparently wild-type protein. Our study has established that genetic inactivation of EP300 is rare in primary colorectal, breast and ovarian cancers. In contrast, mutations are common among colorectal cancer cell lines with 4/17 harbouring homozygous or heterozygous mutations. The rarity of EP300 mutations among these tumour types that show a high frequency of LOH across 22q13 may indicate that another gene is the target of the loss. It is possible that bi-allelic inactivation of EP300 is not necessary and that haploinsufficiency is sufficient to promote tumorigenesis. Alternatively, silencing of EP300 may be achieved by epigenetic mechanisms such as promoter methylation.     

Antiproliferative effect of immunoliposomes containing 5-fluorodeoxyuridine-dipalmitate on colon cancer cells.

We have investigated the antiproliferative action towards CC531 colon adenocarcinoma cells of target cell-specific immunoliposomes containing the amphiphilic dipalmitoyl derivative of 5-fluorodeoxyuridine (FUdR-dP). FUdR-dP incorporated in immunoliposomes caused a 13-fold stronger inhibition of CC531 cell growth in vitro, during a 72-h treatment, than FUdR-dP in liposomes without antibody, demonstrating that the prodrug is efficiently hydrolysed to yield the active drug, FUdR, intracellularly. The intracellular release of active FUdR was confirmed by determining the fate of 3H-labelled immunoliposomal FUdR-dP. Treatments shorter than 72 h with FUdR-dP in immunoliposomes resulted in anti-tumour activities comparable to, or even higher than, that of free FUdR. The shorter treatments reflect more closely the in vivo situation and illustrate the potential advantage of the use of immunoliposomes over non-targeted liposomal FUdR-dP or free FUdR. Association of tumour cell-specific immunoliposomes with CC531 cells was up to tenfold higher than that of liposomes without antibody or with irrelevant IgG coupled, demonstrating a specific interaction between liposomes and target cells which causes an efficient intracellular delivery of the drug. Since biochemical evidence indicates a lack of internalization or degradation of the liposomes as such, we postulate that entry of the drug most likely involves the direct transfer of the prodrug from the immunoliposome to the cell membrane during its antigen-specific interaction with the cells, followed by hydrolysis of FUdR-dP leading to relatively high intracellular FUdR-levels. In conclusion, we describe a targeted liposomal formulation for the anticancer drug FUdR, which is able to deliver the active drug to colon carcinoma cells with high efficiency, without the need for the cells to internalize the liposomes as such.     

Inhibition of integrin alpha5beta1 function with a small peptide (ATN-161) plus continuous 5-FU infusion reduces colorectal liver metastases and improves survival in mice

Integrin alpha(5)beta(1) is expressed on activated endothelial cells and plays a critical role in tumor angiogenesis. We hypothesized that a novel integrin alpha(5)beta(1) antagonist, ATN-161, would inhibit angiogenesis and growth of liver metastases in a murine model. We further hypothesized that combining ATN-161 with 5-fluorouracil (5-FU) chemotherapy would enhance the antineoplastic effect. Murine colon cancer cells (CT26) were injected into spleens of BALB/c mice to produce liver metastases. Four days thereafter, mice were given either ATN-161 (100 mg/kg, every 3rd day) or saline by intraperitoneal injection, with or without combination of continuous-infusion 5-FU (100 mg/kg/2 weeks), which was started on day 7. On day 20 after tumor cell inoculation, mice were killed and liver weights and number of liver metastases were determined. A follow-up study on survival was also conducted in which mice were randomized to receive ATN-161, 5-FU or ATN-161+5-FU. Combination therapy with ATN-161+5-FU significantly reduced tumor burden (liver weight) and number of liver metastases (p<0.02). Liver tumors in the ATN-161 and ATN-161+5-FU groups had significantly fewer microvessels (p<0.05) than tumors in the control or 5-FU-treated groups. Unlike treatment with either agent alone, ATN-161+5-FU significantly increased tumor cell apoptosis and decreased tumor cell proliferation (p<0.03) and improved overall survival (p<0.03, log-rank test). Targeting integrin alpha(5)beta(1) in combination with 5-FU infusion reduced liver metastases formation and improved survival in this colon cancer model. The enhancement of antineoplastic activity from the combination of anti-angiogenic therapy and chemotherapy may be a promising approach for treating metastatic colorectal cancer.     

Weight change and cancer risk in a cohort of more than 65,000 adults in Austria.

BACKGROUND: To investigate relations between weight loss or weight gain and the incidence of cancer. PATIENTS AND METHODS: Weight change was assessed in a population-based cohort of >65 000 Austrian adults (28 711 men and 36 938 women) for a period of 7 years, after which participants were followed for incident cancers over 8 years on average. Incident cancers (other than nonmelanoma skin cancers) were ascertained by a population-based cancer registry (n = 3128). Cox proportional hazards models were used to estimate hazard rate ratios (HRs) stratified by age and adjusted for smoking, occupational group, blood glucose and body mass index at baseline. RESULTS: In both men and women, neither weight loss nor weight gain was clearly associated with the incidence of all cancers combined. Weight loss (>0.10 kg/m(2)/year) was inversely associated with colon cancer in men [HR 0.50; 95% confidence interval (CI) 0.29-0.87], while high weight gain (> or =0.50 kg/m(2)/year) was inversely associated with prostate cancer (HR 0.43; 95% CI 0.24-0.76). Among women, high weight gain was positively associated with ovarian cancer (HR 2.48; 95% CI 1.05-5.85). CONCLUSION: These findings indicate that recent weight change may influence the incidence of several types of cancer.     

Intact LKB1 activity is required for survival of dormant ovarian cancer spheroids

Metastatic epithelial ovarian cancer (EOC) cells can form multicellular spheroids while in suspension and disperse directly throughout the peritoneum to seed secondary lesions. There is growing evidence that EOC spheroids are key mediators of metastasis, and they use specific intracellular signalling pathways to control cancer cell growth and metabolism for increased survival. Our laboratory discovered that AKT signalling is reduced during spheroid formation leading to cellular quiescence and autophagy, and these may be defining features of tumour cell dormancy. To further define the phenotype of EOC spheroids, we have initiated studies of the Liver kinase B1 (LKB1)-5′-AMP-activated protein kinase (AMPK) pathway as a master controller of the metabolic stress response. We demonstrate that activity of AMPK and its upstream kinase LKB1 are increased in quiescent EOC spheroids as compared with proliferating adherent EOC cells. We also show elevated AMPK activity in spheroids isolated directly from patient ascites. Functional studies reveal that treatment with the AMP mimetic AICAR or allosteric AMPK activator A-769662 led to a cytostatic response in proliferative adherent ovarian cancer cells, but they fail to elicit an effect in spheroids. Targeted knockdown of STK11 by RNAi to reduce LKB1 expression led to reduced viability and increased sensitivity to carboplatin treatment in spheroids only, a phenomenon which was AMPK-independent. Thus, our results demonstrate a direct impact of altered LKB1-AMPK signalling function in EOC. In addition, this is the first evidence in cancer cells demonstrating a pro-survival function for LKB1, a kinase traditionally thought to act as a tumour suppressor.     

贝伐珠单抗联合化疗治疗KRAS突变型晚期左、右半结肠癌疗效的对比分析

目的:对比分析姑息一线应用贝伐珠单抗联合化疗治疗KRAS突变型晚期左、右半结肠癌的临床疗效。方法:回顾性分析我院于2016年09月至2020年09月收治的83例一线应用贝伐珠单抗联合化疗治疗KRAS突变型晚期左、右半结肠癌患者,比较KRAS突变型左、右半结肠癌患者的临床特征、客观缓解率（ORR）、疾病控制率（DCR）、无进展生存时间（PFS）、18个月生存率、总生存时间（OS）。结果:KRAS突变型晚期右半结肠癌（RSCC）患者合并不完全肠梗阻及体重减轻＞5 kg所占比例更高（P=0.369、P=0.009）,KRAS突变型晚期左半结肠癌（LSCRC）患者更易合并中重度以上的贫血（P=0.154）。KRAS突变型LSCRC患者发生腹腔种植转移及远处器官转移的患者比例高于RSCC患者（P＞0.05）。KRAS突变型LSCRC患者与RSCC患者ORR分别为29.3%和28.6%（P=0.944）,DCR分别为87.8%和90.5%（P=0.696）。18个月生存率LSCRC组为80.05%,RSCC组为76.2%,差异无统计学意义（P=0.635）。KRAS突变型LSCRC患者中位 PFS差于RSCC患者（8个月 vs 9.8个月,P=0.004）,KRAS突变型LSCRC患者中位OS优于KRAS突变型RSCC患者中位OS（22.8个月 vs 21个月,P=0.001）。结论:姑息一线应用贝伐珠单抗联合化疗治疗KRAS基因突变型mCRC患者,左、右半结肠癌的远期疗效存在差异。     

Angiopoietin-1 inhibits tumour growth and ascites formation in a murine model of peritoneal carcinomatosis

Angiopoietin-1 is an important regulator of endothelial cell survival. Angiopoietin-1 also reduces vascular permeability mediated by vascular endothelial growth factor. The effects of angiopoietin-1 on tumour growth and angiogenesis are controversial. We hypothesised that angiopoietin-1 would decrease tumour growth and ascites formation in peritoneal carcinomatosis. Human colon cancer cells (KM12L4) were transfected with vector (pcDNA) alone (control) or vector containing angiopoietin-1 and injected into the peritoneal cavities of mice. After 30 days, the following parameters were measured: number of peritoneal nodules, ascites volume, and diameter of the largest tumour. Effects of angiopoietin-1 on vascular permeability were investigated using an intradermal Miles assay with conditioned media from transfected cells. Seven of the nine mice in the pcDNA group developed ascites (1.3+/-0.5 ml (mean+/-s.e.m.)), whereas no ascites was detectable in the angiopoietin-1 group (0 out of 10) (P<0.01). Number of peritoneal metastases (P<0.05), tumour volume, (P<0.05), vessel counts (P<0.01), and tumour cell proliferation (P<0.01) were significantly reduced in angiopoietin-1-expressing tumours. Conditioned medium from angiopoietin-1-transfected cells decreased vascular permeability more than did conditioned medium from control cells (P<0.05). Our results suggest that angiopoietin-1 is an important mediator of angiogenesis and vascular permeability and thus could theoretically serve as an anti-neoplastic agent for patients with carcinomatosis from colorectal cancer.     

Risks of cancer due to a single BRCA1 mutation in an extended Utah kindred

Objective Germline mutations in the BRCA1 gene are associated with an increased risk of breast and ovarian cancer, but there is controversy about the true magnitude of these risks. Observed differences can arise from several sources, both genetic and methodological. To examine the efficiency and bias associated with different methods of risk calculation, we analyzed a single mutation in a large pedigree with known ascertainment. Methods Age-specific penetrance of breast and ovarian cancer was estimated using the Kaplan–Meier method and two likelihood-based approaches [maximum likelihood estimation, maximization of the logarithm of the odds (LOD) score]. Excess risk of other cancers due to the BRCA1 mutation was assessed. Results The estimated risk of breast and ovarian cancer at age 70 was 0.80 using the Kaplan–Meier approach and 0.55 using the maximum likelihood method. Both likelihood-based methods yielded similar results for the combined breast/ovarian phenotype, but using the maximum LOD score method lower estimates were obtained if only cancer at one site was considered. In the examined family, a high risk of ovarian cancer was found which might be an effect of the central location of the mutation within BRCA1. The risk of cancer at other sites than breast and ovaries was significantly elevated, but it was not possible to identify a single cancer site that could be said to be associated with the BRCA1 mutation. Conclusion Estimating the penetrance of a specific mutation using different approaches, we found that both the choice of study population and statistical method affect the magnitude of the estimates.     

Brain metastasis as a late manifestation of ovarian carcinoma

CHEN Y‐L., CHENG W‐F., HSIEH C‐Y. & CHEN C‐A. (2011) European Journal of Cancer Care 20 , 44–49
Brain metastasis as a late manifestation of ovarian carcinoma This paper aims to evaluate the clinical characteristics of ovarian cancer patients with cerebral metastases. Ten ovarian cancer patients with brain metastases were retrospectively identified from a total of 539 ovarian cancer patients. Their characteristics before and at the time of diagnosis of cerebral metastases were analysed. The survival of them was also measured. Ten (1.9%) of the 539 ovarian cancer patients had brain metastases in the study period. Nine had stage III or IV tumours with either moderate or poor histological differentiation. The mean time from diagnosis of ovarian cancer to documentation of central nervous system metastasis was 24.3 months, which was 11.1 months if other sites of metastasis were involved before cerebral relapse. All of the patients with intra‐cranial tumours suffered from associated neurological defects and relived by treatments. The median survival time after diagnosis of central nervous system involvement was 3 months. In this study, all ovarian cancer patients with cerebral metastases had clinical neurological symptoms. Physicians should pay more attention to ovarian cancer patients with neurological defects and arrange brain imaging studies for the early diagnosis of brain metastases and prompt management to improve quality of life.     

High antitumour activity of ET743 against human tumour xenografts from melanoma, non-small-cell lung and ovarian cancer

Background: Ecteinascidin-743 (ET743) is a novel antitumour agent originating from the Caribbean tunicate Ecteinascidia turbinata. It has potent cytotoxic and antitumour activity and a potential new mechanism of action. The aim of the present study was to further explore the antitumour activity of ET743 in human tumour xenografts from melanoma, non-small-cell lung and ovarian cancer.Design: As the antitumour profile of ET743 was largely unknown a chemo-sensitive and a marginal chemo-resistant human tumour xenograft were selected for each tumour type. ET743 was administered intravenously using two administration schedules (days 0, 4, 8 and 0–2, 13–15).Results: ET743 was very active at the maximum tolerated dose (MTD) in the chemo-sensitive xenograft melanoma MEXF 989, non-small-cell lung cancer LXFL 529, and ovarian cancers HOC22 and (marginally resistant to cisplatin) HOC18. Activity was also seen at ø12 MTD. Apart from HOC18, ET743 caused complete remissions in the responding xenografts. The compound was inactive in the chemo-resistant xenograft melanoma MEXF 514 and non-small-cell lung cancer LXFA 629. In terms of antitumour activity the days 0, 4, 8 schedule had advantages over the days 0–2, 13–15 schedule.Conclusions: ET743 is a very effective agent in chemo-sensitive and marginal chemo-resistant xenografts, but inactive in chemo-resistant tumour xenografts. The activity of ET743 in the marginally cisplatin-resistant ovarian cancer HOC18 might indicate absence or incomplete cross-resistance against cisplatin. It is recommended to include melanoma, non-small-cell lung cancer, and ovarian cancer in phase II clinical trials and to use an intermittent schedule.     

单壁碳纳米管对结肠癌细胞系SW480生物学行为影响研究

目的 单壁碳纳米管(single-walled carbon nanotubes,SWCNT)作为一维纳米材料具有良好的稳定性与光吸收能力且易倍修饰等特点,已被广泛用于癌症治疗、药物转运等领域.本研究探讨SWCNT对结肠癌细胞系SW480细胞增殖、凋亡和侵袭能力影响,为单壁碳纳米管临床应用提供帮助.方法 低、中和高浓度SWCNT分别与结肠癌细胞系SW480共孵育.CCK-8检测SW480细胞增殖能力,流式细胞仪检测细胞凋亡及周期变化,Transwell实验检测细胞侵袭能力以及共聚焦显微镜(confocal laser scanning microscope,CLSM)观察SWCNT在SW480细胞内的定位;同时分析相关机制.结果 随着SWCNT浓度升高,SW480细胞存活力和细胞侵袭数量依次显著降低,高浓度SWCNT组细胞存活率[(21.43±2.44)％]和侵袭细胞数量(58.34±4.11)最低,显著低于其他组,F值分别为157.094和203.749,多组间差异分析及两两比较均为P＜0.05.随SWCNT浓度升高,SW480细胞凋亡比例依次显著升高,高浓度SWCNT组细胞凋亡率高达(74.26±6.89)％,显著高于其他组,F=115.752,多组间差异分析及两两比较均为P＜0.05.而随SWCNT浓度的升高,G1期受阻SW480细胞比例依次显著增加,高浓度组最高,F=21.293,多组间差异分析及两两比较均为P＜0.05.CLSM显示,SWCNT与SW480细胞线粒体共定位,SWCNT处理后SW480细胞线粒体出现断裂.结论 SWC-NT能够抑制SW480细胞分裂、增殖及迁移,促进细胞凋亡同时引起线粒体断裂.     

Contradictory KRAS mutation test results in a patient with metastatic colon cancer: A clinical dilemma in the era of personalized medicine

The KRAS oncogene is mutated in 40‒50% of colorectal cancers and confers resistance to EGFR-targeted therapy. In the clinic, agents such as cetuximab or panitumumab target the EGFR receptor for therapeutic benefit. Cetuximab was approved by the FDA in 2012 as first-line therapy for KRAS mutation-negative (wild-type), EGFR-expressing metastatic colorectal cancer, in combination with FOLFIRI (5-fluorouracil, irinotecan, leucovorin). Herein we report a case of metastatic colon cancer with conflicting testing results for the KRAS oncogene from two different reference laboratories. The discordant reports complicated the decision-making process regarding the administration of targeted anti-EGFR personalized therapy. As the second test result was wild-type from the same original pathological specimen, the patient was treated with cetuximab-containing combination chemotherapy and appeared to have a response after prior disease progression. It is unclear whether the observed response was fully due to regression of wild-type KRAS-containing tumor or any component of antibody-dependent cellular cytotoxicity to a heterogeneous tumor in this patient.