Mouse embryonic transforming growth factors related to those isolated from tumor cells

Growth factors with the two characteristic properties of sarcoma growth factor, the ability to stimulate anchorage-independent growth of normal mouse or rat fibroblasts and the ability to compete with 125I-labeled epidermal growth factor for receptor binding, can be isolated from 12- to 13-day-old normal mouse embryos of various strains. Two size classes of the transforming factor from embryo cells can be isolated with apparent molecular weights of 20,000 and 10,000. The lower-molecular-weight factor has been purified several hundred-fold and has the same properties as the peptides with a molecular weight of 10,000 produced by mouse sarcoma virus-transformed 3T3 cells. Whole-mouse embryos contain approximately 10% as much sarcoma growth factor per g of tissue as do the murine sarcoma virus-transformed cells; how it is distributed among the embryonic tissues remains to be determined.     

Sensitivity to temozolomide in brain tumor initiating cells

Molecular alterations in glioblastoma have the potential to guide treatment. Here, we explore the relationship between temozolomide (TMZ) response and O⁶-methylguanine DNA methyltransferase (MGMT) status in brain tumor initiating cells (BTICs). Methylation, expression, and sensitivity were assessed in 20 lines; associations were evaluated by Fisher''s exact test. Some BTICs were sensitive. Sensitivity to TMZ was only associated with protein expression (P = .001). There were atypical BTICs including TMZ-resistant lines in which the methylation-specific PCR reaction revealed both methylated and unmethylated bands. BTICs are not uniformly resistant to TMZ; some are sensitive. MGMT status does not predict TMZ response with high precision.     

Polyamines and hormonal regulation of N-nitrosomethylurea-induced rat mammary tumor growth in vivo

We have observed that polyamines play an essential role in the expression of hormonal action on the growth of the N-nitrosomethylurea-induced mammary tumor cultured in soft agar. Since polyamine levels cannot be measured in this system, we could not determine whether tumor polyamine pools are under endocrine control. To test this hypothesis, the following experiments were conducted in N-nitrosomethylurea tumor-bearing rats in vivo. Both tamoxifen administration (200 micrograms/day) and ovariectomy produced dramatic reductions in tumor growth but neither treatment significantly altered tumor polyamine levels after either 7 or 21 days of treatment. Some decrease in tumor level of putrescine, spermidine, and spermine was observed 21 days after ovariectomy but it was not statistically significant. Exogenous administration of putrescine (300 mg/kg/day) reversed the antitumor effect of tamoxifen but did not prevent tumor regression induced by ovariectomy. This effect of putrescine was, however, variable in magnitude from experiment to experiment. To test whether the reversal of tamoxifen effect by putrescine might simply be due to interference with tamoxifen uptake by the tumor cells, we measured estrogen and progesterone receptors in the tumors of rats chronically treated with tamoxifen and tamoxifen plus putrescine. In both groups estrogen receptors are virtually undetectable, thus suggesting that putrescine had not inhibited tamoxifen entry into the cells and binding to estrogen receptors. Progesterone receptor levels were similarly high in both groups and not significantly different from control. These results indicate that at least under these experimental conditions N-nitrosomethylurea mammary tumor polyamine pools are not under ovarian hormone control. The mechanism by which putrescine reverses tamoxifen's effect remains unclear.     

Use of lymph in cell culture to model hormonal and nutritional constraints on tumor growth in vivo

Transformed BALB/3T3 cells, which proliferate without restraint in culture, consistently produce rapidly growing sarcomas when 10(5) or more cells are inoculated into nude mice but produce sarcomas, of widely varying latent periods and growth rates, or negatives when 10(4) or fewer cells are inoculated. In an attempt to simulate the in vivo constraints on tumor development, these cells were cultured on plastic surfaces in concentrations of lymph up to 100%. Calf lymph was less effective in supporting multiplication than calf serum at all concentrations up to about 50%. The rate of cell multiplication progressively decreased with increasing concentrations of both fluids above 50%. Nonetheless, rapid multiplication could be achieved even in 100% serum or lymph by supplementing them with the high concentrations of nutrients used in the synthetic medium MCDB 402. Supplementation of cystine and glutamine was essential for the growth-enhancing effects of the other nutrients. When the cells were suspended in agar, lymph was much less effective than serum in promoting colony formation even when both were supplemented with cystine and glutamine, or with all the constituents of the synthetic medium. We conclude that part of the low efficiency of tumor production and reduced growth rate of the transformed cells in mice resulted from a combination of (a) the paucity of growth factors in interstitial fluid, (b) the marked reduction in concentration of essential amino acids encountered by the cells in passing from culture into mice, and (c) the fact that cells multiplying in s.c. space do so without benefit of attachment to a solid substratum. Other factors, such as the growth inhibiting effects of direct contact with quiescent muscle and connective tissue cells, remain to be evaluated.     

恶性肿瘤自愈的调查及相关因素

目的：调查癌症自愈部位及类型，探讨癌症自愈相关因素。方法：根据癌症自愈4项诊断标准及随访无瘤生存时间确定病例。结果：一些癌症可能自愈，但是以肾上腺这一部位为最高。结论：癌症自愈有规律，研究癌症自愈的相关因素为临床应用奠定基础。对肿瘤自愈的研究是攻克癌症的重要方法。     

凋亡相关因子与卵巢肿瘤研究进展

细胞凋亡又称程序性细胞死亡,其在卵巢肿瘤中起着举足轻重的作用.研究发现,凋亡相关因子的调控失衡直接导致卵巢肿瘤的发生发展,影响肿瘤的预后和治疗.现详述几类重要的凋亡相关因子与卵巢肿瘤的最新研究动态.     

Characteristics of lung cancer in women: importance of hormonal and growth factors

Based on epidemiological, clinical, and preclinical data, lung carcinogenesis can be distinctive in women, suggesting that women should be treated differently depending on the expression of various specific biomarkers. We aimed to describe the hormonal and genetic profile of lung cancer in both men and women to identify gender specificities. Primary lung-tumor tissues from surgically treated patients, (50 men, 50 women) were analyzed and compared for expression of estrogen receptors (ER) α and β, progesterone receptors (PR), epidermal growth-factor receptor (EGFR), and HER2 (for EGFR and K-Ras mutations). These data were combined with clinical and outcome data. Fewer women with lung cancer were smokers (p=0.001) and they smoked fewer cigarettes (p=0.001). We observed a higher rate of EGFR mutations (p=0.02) and ERα expression (p=0.006) in women. ERβ and EGFR were also expressed more frequently in women (p=0.29 and p=0.16). HER2 was overexpressed regardless of gender in three men and two women. K-Ras was mutated in 16% of both men and women. Interestingly, there was a positive link between EGFR expression and expression of ERα (p=0.028) and ERβ (p=0.047) in both men and women. Expression of ERα was associated with improved disease-free survival (p=0.007). Our findings provide further evidence on the specificities of lung cancer in women. The differential expression of specific biomarkers, which could be targeted by therapy, favors the development of gender-based treatment guided by biomarker expression.     

Sensitivity to bleomycin of human cultured tumor cells and analysis of related factors

Several types of human cultured tumor cells were tested for the sensitivity to BLM, an effective antitumor antibiotic for epidermoid (squamous cell) carcinomas. Three cell lines (HeLa, KB, Hepd) derived from epidermoid carcinomas were very sensitive to BLM under concentrations tested, whereas BLM-resistant HeLa cells (HeLa-BLMr), neoplastic cells derived from salivary glands (HPA, HSG), malignant fibrous histiocytoma (MFH) and melanoma (MEC) were much less sensitive to BLM than epidermoid carcinoma cell lines under the same conditions. To investigate the possible mechanism of BLM resistance, these cell lines, namely HeLa, HeLa-BLMr, HSG and MEC, were examined for i) BLM permeability into cells by using 3H-PEP which was a new derivative of BLM, ii) BLM-inactivating activity in cell extracts by bioassay for antibacterial activity with B. subtilis PCI 219 strain, and iii) DNA repair activity after UV irradiation. Consequently, as compared with BLM-sensitive HeLa cells, BLM less sensitive HeLa-BLMr, HSG and MEC cells showed 34%, 50% and 39% reduction per 10(6) cells in BLM permeability, 1.6-, 5.6- and 4.7-fold increase per mg protein in BLM inactivating activity, and 24.5-, one and 8-fold enhancement in DNA repair activity, respectively. Therefore, it was indicated that above three factors at least were involved in the BLM sensitivity of human tumor cells.     

Selective expression of constitutively active pro-apoptotic protein BikDD gene in primary mammary tumors inhibits tumor growth and reduces tumor initiating cells

Our previous study showed that specifically delivering BikDD, a constitutive active mutant of pro-apoptotic protein Bik, to breast cancer cell xenografts in immunocompromised mice has a potent activity against tumor initiating cells (TICs), and that the combination between tyrosine kinase inhibitors (TKI) and BikDD gene therapy yielded synergistic effect on EGFR and HER2 positive breast cancer cells in immunodeficient nude mice. Those encouraging results have allowed us to propose a clinical trial using the liposome-complexing plasmid DNA expressing BikDD gene which has been approved by the NIH RAC Advisory committee. However, it is imperative to test whether systemic delivery of BikDD-expressing plasmid DNAs with liposomes into immunocompetent mice has therapeutic efficacy and tolerable side effects as what we observed in the nude mice model. In this study, we investigated the effects of BikDD gene-therapy on the primary mammary tumors, especially on tumor initiating cells (TICs), of a genetically engineered immunocompetent mouse harboring normal microenvironment and immune response. The effects on TIC population in tumors were determined by FACS analysis with different sets of murine specific TIC markers, CD49f^highCD61^high and CD24⁺Jagged1^-. First we showed in vitro that ectopic expression of BikDD in murine N202 cells derived from MMTV-HER2/Neu transgenic mouse tumors induced apoptosis and decreased the number of TICs. Consistently, systemic delivery of VISA-Claudin4-BikDD by liposome complexes significantly inhibited mammary tumor growth and slowed down residual tumor growth post cessation of therapy in MMTV-HER2/Neu transgenic mice compared to the controls. In addition, the anti-tumor effects of BikDD in vivo were consistent with decreased TIC population assessed by FACS analysis and in vitro tumorsphere formation assay of freshly isolated tumor cells. Importantly, systemic administration of BikDD did not cause significant cytotoxic response in standard toxicity assays or body weight changes. Taken together, our findings validated that selective expression of BikDD in the primary mammary tumors in immunocompetent hosts significantly reduced tumor burden and inhibited the residual tumor growth at off-therapy stage by eliminating TICs. Hence, the VISA-Claudin4-BikDD-mediated gene therapy is worthy of further investigation in breast cancer clinical trials.     

骶骨肿瘤术后切口并发症的相关因素分析

目的分析骶骨肿瘤术后切口并发症的原因。方法2003年1月～2008年12月23例骶骨肿瘤行手术切除,手术时平均年龄42岁（16～68岁）;男性10例,女性13例。其中脊索瘤8例、骨巨细胞瘤6例、神经纤维瘤1例、恶性神经鞘瘤1例,转移瘤3例、骨母细胞瘤1例、骨肉瘤2例、软骨肉瘤1例。统计分析患者性别,年龄,肿瘤性质,有无糖尿病,肥胖,吸烟,是否应用激素,以前是否有过手术,放疗,术前是否行化疗,动脉栓塞,手术时间,出血量,手术入路,有无脑脊液漏,术后膀胱和肠道功能情况。应用Logistic回归分析了解以上因素与术后切口并发症的关系。结果6例患者（26％）术后出现切口并发症。增加并发症发生的因素有以前做过手术（P=0．016;OR8．01）,手术时间〉3h（P=0.036;OR3．79）,年龄〉50岁（P=0.076;OR1．59）,术后膀胱和肠道功能障碍（P=0．089;OR2．53）。结论骶骨肿瘤切除手术切口并发症与再次手术,手术时间长,高龄患者以及术后膀胱和肠道功能障碍因素相关。     

Host factors in the susceptibility of mice to tumour initiating and promoting agents

It has been known for a long time that skin tumours can be induced by the sequential application of a subthreshold dose of a carcinogen (initiation stage) followed by repetitive treatment with a noncarcinogenic promoter (promotion stage). In mouse skin, the initiation stage requires only a single application of either a direct-acting carcinogen or a procarcinogen and is essentially an irreversible step, which, as data suggest, probably involves a somatic cell mutation. The promotion stage in mouse skin can be accomplished by a wide variety of weak or noncarcinogenic agents and is initially reversible, later becoming irreversible. Current information suggests that skin tumour promoters are not mutagenic but bring about a number of important epigenetic changes, such as epidermal hyperplasia and an increase in levels of polyamines, prostaglandins and dark basal keratinocytes as well as other embryonic conditions. Recently, tumour promotion in mouse skin was shown to consist of at least two stages, each of which can be accomplished by either a known promoter or a weak or nonpromoting agent. Some of the important characteristics of the first stage of promotion are: (1) only one application of a first-stage promoter, such as phorbol ester tumour promoters, calcium ionophore A23187, hydrogen peroxide and wounding, is needed; (2) it is partially irreversible; (3) increases in dark basal keratinocytes and prostaglandins are important; and (4) it can be inhibited by anti-inflammatory steroids and protease inhibitors. The second stage of promotion is initially reversible but later becomes irreversible. Polyamines and epidermal cell proliferation are important events in the second stage of promotion. A number of weak or nonpromoting agents, such as mezerein, are effective second-stage promoters, which can be counteracted by retinoic acid, anti-inflammatory steroids and polyamine synthesis inhibitors. Although skin tumour promotion has been studied extensively in mice, not all strains and stocks of mice are susceptible to phorbol ester tumour promoters. In this regard, C57Bl/6 mice appear to be fairly resistant to these tumour promoters. Not all species are equally susceptible to phorbol ester tumour promotion (mouse greater than rat greater than hamster, and the miniature swine is fairly resistant). It is not presently known if other experimental systems of carcinogenesis or the induction of human cancer go through a series of stages similar to that in the mouse skin.     

Vascular endothelial growth factor expression is closely related to irinotecan-mediated inhibition of tumor growth and angiogenesis in neuroblastoma xenografts

In the present study, irinotecan (CPT-11) was highly effective not only against the chemosensitive neuroblastoma (NB) xenografts SK-N-AS nu and TNB9, but also against the multidrug-resistant NB xenograft TS-N-2 nu . SK-N-AS nu and TNB9 were significantly more responsive to low-dose daily CPT-11 treatment than to intermittent administration of one-third of the median lethal dose. For TS-N-2 nu , there was no significant difference in tumor growth inhibition between the two treatment schedules. Treatment with CPT-11 alone could not completely abolish tumor growth in mice. For TNB9, tumor regrowth seemed to result from an inability to regress host vessels in the stroma during treatment and an inability to suppress host-derived vascular endothelial growth factor (VEGF) expression throughout therapy. In the multidrug-resistant TS-N-2 nu , VEGF was not suppressed by low-dose therapy with CPT-11, and neurofilament-positive tumor cells escaped from apoptosis and were growth arrested at G₀/G₁ phase. These findings suggest a mechanism for the incomplete responsiveness of TS-N-2 nu to CPT-11. Our data demonstrate that diminished VEGF gene and protein expression is closely correlated with tumor growth inhibition and inhibition of angiogenesis by CPT-11 in NB xenografts. Our results further suggest that a persistent blocker of stroma-derived VEGF will need to be combined with CPT-11 to completely inhibit the growth of chemosensitive NB, and that administration of CPT-11 at higher doses will be required to inhibit the growth of multidrug-resistant NB. ( Cancer Sci 2008; 99: 1209–1217)     

Recurrences of meningiomas: predictive value of pathological features and hormonal and growth factors

Summary Objective Recurrence of apparently completely resected benign meningiomas is a rather frequent event, the mechanisms of which are still unclear. The aim of this study is to define the pathological features, proliferation indexes, growth factors and hormone receptor expression in predicting the meningioma recurrence. Methods Two groups of 50 completely resected benign WHO I meningiomas, with and without recurrence respectively, have been reviewed. Tumor location, consistency, vascularity, and histological types have been considered. Immunohistological studies include mitotic index (MI), Ki-67 LI, estrogen and progesterone receptors (ER and PR), Vascular Endothelial Growth Factor (VEGF), Epidermal Growth Factor (EGF), and Bcl-2. All these factors have been correlated with the recurrence. Results The tumor recurrence was not correlated with the patient age, tumor location, consistency, vascularity and histology. There was not difference in the histological pattern between local and diffuse recurrences. M.I. and Ki-67 LI were significantly correlated with the recurrence (P<0.0001). PR negativity had a strong predictive value of recurrence (P<0.0001), whereas the ER status was not relevant. VEGF and EGF-R were not correlated with the recurrence of meningiomas, whereas the Bcl-2 protein positivity showed a tendency to the significativity (P=0.0294). The negative association between Bcl-2 and PR is an interesting finding of our study. Conclusions Higher MI and Ki-67 LI and PR negativity are predictive factors of recurrence of benign (WHO I) completely resected meningiomas, particularly when Bcl-2 positivity is associated.     

Modified responsiveness of v-Ha-ras-transfected rat fibroblasts to growth factors and a tumor promoter

The correlation of the phenotypic changes of v-Ha-ras transfected cells with the expression of p21ras and the modified responses to growth factors and a tumor promoter were examined. Transfection of the v-Ha-ras gene together with the neomycin-resistance gene into 208F rat fibroblasts yielded transformed clones characterized by morphological changes, anchorage-independent growth, and tumorigenicity in nude mice. The degrees of these biological alterations were parallel with the expression of mRNA and protein of the ras gene. In ras-transformed cells, anchorage-independent growth was stimulated by epidermal growth factor (EGF), insulin, bombesin, and fibroblast growth factor, whereas in the parental 208F cells, anchorage-independent growth was observed only in the presence of EGF, and there were many fewer EGF-induced colonies than those in the ras-transformed clones. A tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA) also augmented anchorage-independent growth of ras-transformed cells and induced morphological changes in monolayer cultures without altering the expression of the ras gene or phosphorylation of the p21ras protein. Retinoic acid inhibited the TPA-induced anchorage-independent growth. These results showed a good correlation of the expression of p21ras with the phenotypic changes and the increased sensitivity of the p21ras-expressing cells to the stimulation of growth factors and tumor promoter.     

A novel orthotopic tumor model to study growth factors and oncogenes in hepatocarcinogenesis.

An orthotopic xenograft tumor model of hepatocellular carcinoma was created by injection of Hep 3B cells directly into the liver parenchyma of nude mice. Tumors were localized primarily in the injected lobe of the liver, beginning from the third week after tumor cell implantation. Thereafter, tumors grew rapidly, and animals usually died from hepatocellular carcinoma within 2 months. Insulin-like growth factor II, an embryonic growth factor and mitogen, is overexpressed in these tumors at both mRNA and protein levels. Oncogenes, such as c-myc, c-fos, and c-jun, are also up-regulated in this model. alpha-Fetal protein can be detected shortly after implantation and correlates with tumor growth, and measurement of serum alpha-fetal protein serves as an early biomarker to monitor the effect of antitumor therapy. Using this model, we have shown that inhibition of insulin-like growth factor II expression by a short methylated oligonucleotide prolongs survival. This in situ tumor model thus provides a fast, reliable, and reproducible means to study the therapeutic effect of inhibitors of growth factors and oncogenes in liver cancer.     

肝癌衍生生长因子在肿瘤中的表达及其相关信号通路

近年来发现肝癌衍生生长因子(HDGF)的表达与多种恶性肿瘤的发生、进展、转移、治疗和预后密切相关.尽管HDGF与肿瘤相互作用的机制尚不明确,但将HDGF作为肿瘤标志物及肿瘤治疗的新标靶已成为肿瘤研究的一个热点.     

Genetic variation in insulin-like growth factors and brain tumor risk

Many studies support a role for insulin-like growth factors (IGFs) in the regulation of tumor cell biology. We hypothesized that single-nucleotide polymorphisms (SNPs) in IGF genes are risk factors for glioma and meningioma. To test the hypothesis, we examined associations of brain tumor risk with nine variants in five IGF genes in a hospital-based case-control study. The study was conducted at hospitals in Boston, Phoenix, and Pittsburgh between 1994 and 1998. Eligible cases were individuals (18 years or older) newly diagnosed with glioma or meningioma. Controls were selected among patients who were admitted to the same hospitals for a variety of nonmalignant conditions and frequency matched to cases by hospital, age, sex, race, and distance from residence. The present analysis was restricted to non-Hispanic whites. DNA was extracted from blood samples collected from 354 glioma cases, 133 meningioma cases, and 495 control individuals. We evaluated nine SNPs in five IGF genes (IGF1, IGF1R, IGF2, IGF2R, and IGFBP3). The majority of the analyzed IGF SNPs did not display statistically significant associations with glioma or meningioma. For glioma, one IGF1R SNP (rs2272037) indicated a possible association. No indications of association were seen for glioblastoma, but for low-grade gliomas, the odds ratio under a dominant model was 0.56 (95% confidence interval [CI], 0.35-0.90) for IGF1 rs6220, 2.98 (95% CI, 1.65-5.38) for IGF1R rs2272037, and 1.60 (95% CI, 0.90-2.83) for IGF1R rs2016347. Overall, our results do not provide strong evidence of associations of brain tumor risk with IGF polymorphic variants but identify several associations for glioma that warrant further examination in other, larger studies.     

Tamoxifen-induced estrogen receptor up-regulation in mammary tumor cells is not related to growth inhibition

 Treatment of estrogen receptor (ER)-positive mammary tumors with tamoxifen produces a dramatic accumulation of ER in the cell nucleus. We investigated whether this phenomenon might be related to the antitumor activity of the drug. Five tamoxifen derivatives for which an influence on MCF-7 cell growth had previously been established were tested for that purpose; two of them inhibited growth, one was growth-stimulatory, and the remaining two were without significant effect. At 1 μM all compounds up-regulated ER in the cell nucleus after 3 days of culture, suggesting that the ER accumulation does not predict the response to tamoxifen treatment. An analysis of a tamoxifen-resistant clone (RT×6 cells) under similar experimental conditions led to the same conclusion: the ER level significantly increased in the presence of tamoxifen and its 4-hydroxy metabolite. Received: 30 June 1996 / Accepted: 30 September 1996