Modulation of the invasive phenotype of human colon carcinoma cells by organ specific fibroblasts of nude mice

We examined whether fibroblasts from subcutaneous, colon or lung tissues of nude mice influence the invasive potential of highly metastatic human colon carcinoma KM12SM cells. Primary cultures of nude mouse fibroblasts from skin, lung and colon were established. Invasive and metastatic KM12SM cells were cultured alone or with fibroblasts. Growth and invasive properties of the KM12SM cells were evaluated as well as their production of gelatinase activity. KM12SM cells were able to grow on monolayers of all three fibroblast cultures but did not invade through skin fibroblasts. The conditioned media of KM12SM cells cocultured with skin, colon or lung fibroblasts were examined for the presence of type IV collagenase (gelatinase). KM12SM growing on plastic and on colon or lung fibroblasts produced significant levels of latent and active forms of 64 kDa type IV collagenase, whereas KM12SM cells cocultivated with nude mouse skin fibroblasts did not. In contrast, human squamous cell carcinoma A431 cells produced significant levels of collagenase type IV when cocultured with nude mouse skin fibroblasts, a tissue they invaded and completely penetrated. Incubation of KM12SM cells in serum-free medium containing recombinant human interferon-beta (fibroblast interferon) was associated with significant reduction in gelatinase activity. Since the production of type IV collagenase by human colon cancer cells is specifically inhibited by mouse skin fibroblasts but not by colon or lung fibroblasts the data suggest that organ-specific fibroblasts can influence the invasive and metastatic properties of KM12SM cells.     

Bacteria-Based Analysis of HIV-1 Vpu Channel Activity

HIV-1 Vpu is a small, single-span membrane protein with two attributed functions that increase the virus'' pathogenicity: degradation of CD4 and inactivation of BST-2. Vpu has also been shown to posses ion channel activity, yet no correlation has been found between this attribute and Vpu''s role in viral release. In order to gain further insight into the channel activity of Vpu we devised two bacteria-based assays that can examine this function in detail. In the first assay Vpu was over-expressed, such that it was deleterious to bacterial growth due to membrane permeabilization. In the second and more sensitive assay, the channel was expressed at low levels in K⁺ transport deficient bacteria. Consequently, Vpu expression enabled the bacteria to grow at otherwise non permissive low K⁺ concentrations. Hence, Vpu had the opposite impact on bacterial growth in the two assays: detrimental in the former and beneficial in the latter. Furthermore, we show that channel blockers also behave reciprocally in the two assays, promoting growth in the first assay and hindering it in the second assay. Taken together, we investigated Vpu''s channel activity in a rapid and quantitative approach that is amenable to high-throughput screening, in search of novel blockers.     

A microassay for the rapid and selective binding of cells from solid tumors to mouse macrophages

Summary A microassay was developed to study the rapid binding characteristics of murine macrophages activated by gamma interferon and muramyl dipeptide to adherent neoplastic or nonneoplastic target cells. The binding of tumor cells to both activated and nonactivated macrophages was time- and temperature-dependent, and independent of tumor cell type. Activated macrophages bound more tumor cells than nonactivated macrophages. The initial binding of macrophages to target cells did not necessarily lead to lysis. First, primed macrophages bound tumor cells but did not lyse them, and second, nonactivated macrophages bound nontumorigenic cells without subsequent lysis. The rapid binding assay described here could prove useful in investigating the recognition mechanism(s) between macrophages and tumor cells derived from solid primary and metastatic cancers.     

The functional role of reactive stroma in benign prostatic hyperplasia

The human prostate gland is one of the only internal organs that continue to enlarge throughout adulthood. The specific mechanisms that regulate this growth, as well as the pathological changes leading to the phenotype observed in the disease benign prostatic hyperplasia (BPH), are essentially unknown. Recent studies and their associated findings have made clear that many complex alterations occur, involving persistent and chronic inflammation, circulating hormonal level deregulation, and aberrant wound repair processes. BPH has been etiologically characterized as a progressive, albeit discontinuous, hyperplasia of both the glandular epithelial and the stromal cell compartments coordinately yielding an expansion of the prostate gland and clinical symptoms. Interestingly, the inflammatory and repair responses observed in BPH are also key components of general wound repair in post-natal tissues. These responses include altered expression of chemokines, cytokines, matrix remodeling factors, chronic inflammatory processes, altered immune surveillance and recognition, as well as the formation of a prototypical 'reactive' stroma, which is similar to that observed across various fibroplasias and malignancies of a variety of tissue sites. Stromal tissue, both embryonic mesenchyme and adult reactive stroma myofibroblasts, has been shown to exert potent and functional regulatory control over epithelial proliferation and differentiation as well as immunoresponsive modulation. Thus, the functional biology of a reactive stroma, within the context of an adult disease typified by epithelial and stromal aberrant hyperplasia, is critical to understand within the context of prostate disease and beyond. The mechanisms that regulate reactive stroma biology in BPH represent targets of opportunity for new therapeutic approaches that may extend to other tissue contexts. Accordingly, this review seeks to address the dissection of important factors, signaling pathways, genes, and other regulatory components that mediate the interplay between epithelium and stromal responses in BPH.     

一种基于多特征的大肠杆菌启动子判别算法

主要对从一段DNA序列中提取出信息以判别其中是否含有启动子的问题进行了研究。首先从固定长度的序歹4中提取成分特征和结构特征,然后将这些特征输入到一个非线性分类器中进行判别。测试结果显示,在正集＆非编码区负集中,平均错误率降低为13．4％;在正集＆编码区负集中,平均错误率降低到17．0％。表明该方法是非常有效的。     

Destruction of tumor cells by monokines released from activated human blood monocytes: evidence for parallel and additive effects of IL-1 and TNF

Summary The incubation of human peripheral blood monocytes with endotoxins activates the cells to lyse tumorigenic targets directly and also induces the production and release into the culture medium of factors that produce lysis of mouse-transformed fibroblasts L-929 (tumor necrosis factor (TNF)-sensitive) and human A-375 melanoma cells (interleukin-1 (IL-1)- and TNF-sensitive). Immunoblotting analysis revealed that the culture medium of endotoxin-activated but not of control monocytes contained both IL-1 and TNF with a molecular weight of 17,000 daltons each. TNF activity was determined by lysis of L-929 cells, and IL-1 activity was measured by the proliferation of D-10 cells. The production of IL-1 and TNF was concentration-dependent, and the amounts of these monokines were paralleled. The antitumor activity of the culture supernates from endotoxin-treated monocytes was significantly decreased by incubation with heterologous antisera to IL-1, TNF, or both. Recombinant human IL-1 and TNF were used in parallel experiments and as positive controls. Each monokine used produced cytotoxic effects in susceptible targets. The combination of IL-1 and TNF, which more likely resembles culture supernates of activated macrophages, produced an additive antitumor cytotoxicity effect.     

枯草芽孢杆菌262XY2'菌剂对番茄枯萎病的预防效果及其对相关抗性生化指标的影响

【目的】以番茄为供试作物,研究枯草芽孢杆菌262XY2''菌剂对番茄枯萎病的预防效果及其对番茄植株和根际土壤生化指标的影响,以期为菌剂在农业生产制备和生物安全应用中提供理论依据。【方法】设置不同固态菌剂添加量(分别占育苗基质质量的0.5%、1.0%、2.0%、3.0%和4.0%)的试验处理组与不添加固态菌剂的对照组(CK)进行番茄育苗,番茄四叶一心后移栽至花盆进行盆栽试验,定植6周后按照病情程度分级法测定供试菌剂对盆栽番茄枯萎病的预防效果;并测定番茄植株过氧化氢酶活性、过氧化物酶活性、超氧化物歧化酶活性、几丁质酶活性和总巯基含量以及番茄根际土壤游离氨基酸含量、过氧化氢酶活性、N-乙酰-β-D-葡萄糖苷酶活性和脲酶活性等生化指标。【结果】0.5%菌剂处理的番茄根际土壤中游离氨基酸含量比CK高44.325%,N-乙酰-β-D-葡萄糖苷酶活性比CK高108.848%,过氧化氢酶活性比CK高16.472%,均为最高值;1.0%菌剂处理对番茄枯萎病的预防效果最佳,为73.485%,1.0%菌剂处理的番茄植株过氧化氢酶活性比CK高55.742%,过氧化物酶活性比CK高47.404%,超氧化物歧化酶活性比CK高39.433%,几丁质酶活性比CK高209.989%、番茄根际土壤脲酶活性比CK高12.063%,均为最高值;总巯基含量则以2.0%菌剂处理最高,比CK高191.304%。【结论】总体上,0.5%、1.0%和2.0%菌剂处理均不同程度提高了番茄防御酶活性,改善了番茄根际土壤的生化性质,3.0%和4.0%菌剂处理对番茄及其根际土壤各项生化指标影响效果不明显,甚至产生抑制作用。