Effects of chemotherapeutic agents on alpha-fetoprotein secretion and growth of human hepatoma cell lines in vitro

The effects of various chemotherapeutic agents on alpha-fetoprotein (AFP) secretion and growth of human hepatocellular carcinoma and hepatoblastoma cell lines were investigated in vitro. It was found that there was a high correlation between hepatoma cell number and AFP secretion after treatment and that the amount of AFP secreted per cell per 72 h was not affected with therapeutically achievable concentrations. These results suggest that serum AFP level in patients with hepatomas does not correlate with the size of whole tumour but with that of viable tumour mass, and that AFP-secreting capacity of tumour cells in the mass is kept unchanged after chemotherapy.     

Chromosomes of human hepatoma cell lines

The karyotypes of three human hepatoma cell lines Hep G2, Hep 3B and PLC/PRF/5 were investigated by G- and C-banding techniques. In addition to ploidy changes, typical for most carcinoma cell lines, certain markers were found that remained stable throughout passage of these cultures. Chromosome I is involved in multiple translocations, resulting in at least three copies of the chromosome I heterochromatin region in each cell line. Inversion in the 9qh region is also seen. In addition, each of the cell lines consistently contains trisomy of 17q. The rearrangements of chromosome I are most striking in the Hep 3B and PLC/PRF/5 cell lines, which are derived from human hepatocellular carcinomas and contain integrated copies of the hepatitis B viral genome. These two cell lines are characterized by the presence of at least five copies of the I (p13←q21) region that result from multiple deletions and/or translocations; by consistent trisomy and polymorphism of the 9qh region; and by trisomy of chromosome 10 (also involved in rearrangements). The Hep G2 and Hep 38 cell lines behave functionally as highly differentiated liver parenchymal cells and are karyologically distinguishable from PLC/PRF/5 both by the presence of trisomy of 6 (pter←q14) and by the finding that one of the homologues of chromosome 15 is 15q+.     

The mechanism of action of Kahalalide F: variable cell permeability in human hepatoma cell lines

Kahalalide F (KF) is a small natural peptide that showed activity in vitro and in vivo. The dose-limiting toxicity in clinical trials was transaminitis. We investigated the cytotoxicity of KF in cell lines from breast, ovary, prostate and colon cancers, but focused on hepatoma cell lines, performing mechanistic studies in HepG2 (IC50 = 0.3 microM) and PLC/PRF/5C (IC50 = 5 microM). Following KF exposure, HepG2 cells demonstrated profound ATP depletion, associated with cell swelling and cell blebbing, and increased permeability to propidium iodide (PI), annexin V (AV) and release of lactate dehydrogenase (LDH). PLC/PRF/5C cells retained their cell structure, but were permeable to PI and, following exposure to high concentrations of KF, to AV. The pattern of cell permeability is similar to maitotoxin, another small cytotoxic peptide, but the differential effects on the cell membrane induced by KF in HepG2 and PLC/PRF/5C suggest specific interactions with membranes or proteins. This could lead to better drug design aimed at exploiting the potential for cell selectivity.     

Targeted killing of colorectal cancer cell lines by a humanised IgG1 monoclonal antibody that binds to membrane-bound carcinoembryonic antigen

The distribution of carcinoembryonic antigen (CEA) in colorectal cancer (CRC) differs from that in normal colorectal tissue, being found on all borders of the cell membrane and hence enabling access to intravenous antibody, making CEA a good target for antibody-based therapy. The distinctive anti-CEA antibody, PR1A3, binds only membrane-bound CEA. Humanised PR1A3 (hPR1A3) was assessed both in vitro cytotoxicity and binding assays with colorectal cancer cell lines expressing varying levels of CEA. Human peripheral blood mononuclear cells (PBMCs) and purified natural killer (NK) cells were used as effectors. The in vitro assays demonstrated hPR1A3 CEA-specific binding and antibody-dependent and CEA-specific killing of human colorectal cancer cell lines by human PBMCs. The effect increased with increasing concentration of antibody and surface CEA, and was lost by using the parent murine IgG1 PR1A3. Killing was also blocked by antibody to the Fc-gammaIIIA receptor. Purified human NK cells were effective at much lower effector:target ratios than unfractionated PBMCs, indicating that NK cells were the main mediators of hPR1A3-based CEA-specific killing. The results support the development of hPR1A3 for therapy of colorectal cancer.     

Inhibition of growth of human lung adenocarcinoma cell lines by anti-transforming growth factor-alpha monoclonal antibody

We previously reported that two human lung adenocarcinoma cell lines (A-549 and PC-9) produce human transforming growth factor-alpha (hTGF-alpha) and express its receptors. In the present study an exogenously added monoclonal antibody against recombinant hTGF-alpha inhibited growth of these cell lines in vitro. This result indicated that endogenous hTGF-alpha produced by the cancer cells can function as an autocrine growth factor.     

Glycoproteins distinguishing non-small cell from small cell human lung carcinoma recognized by monoclonal antibody 43-9F

Cell lines derived from human squamous lung carcinoma release large amounts of a soluble glycoprotein into the culture media, having very high molecular weight (greater than 2 X 10(6] and mucin-like properties. A monoclonal antibody called 43-9F has been generated that recognizes a carbohydrate epitope on the glycoconjugate. The epitope is also present on a diverse set of smaller glycoproteins (Mr 50,000-200,000) distributed primarily on the surface of the squamous lung carcinoma cells. A sensitive assay using the 43-9F antibody in a dot blot procedure has been devised that is able to detect an amount of antigen less than that possessed by a single squamous lung carcinoma cell. This assay, and also conventional immunofluorescence and immunohistochemical assay procedures, have been used to screen different normal cells, normal tissues, cancer cells, and tumor biopsy specimens for the antigen. In the normal lung the 43-9F antigen is found only on cells of some of the seromucous glands. In the normal digestive system it is associated in certain organs only with a limited population of mucosal epithelial cells. Other organ systems lack any reactive cells. The cells of most human non-small cell lung carcinomas and their released glycoconjugates have large amounts of the 43-9F epitope, while small cell lung carcinomas and the glycoconjugates released by small cell lung cancer cells lack the epitope. The oligosaccharide recognized by the 43-9F antibody may therefore provide a useful marker to distinguish the different lung carcinomas and for investigating the different cells of origin of these tumors.     

Multidrug resistance in cultured human leukemia and lymphoma cell lines detected by a monoclonal antibody, MRK16

Forty cultured human leukemia and lymphoma cell lines never exposed to anticancer agents in culture, apart from doxorubicin (ADM)-resistant K562/ADM, were examined for reactivity with a monoclonal antibody, MRK16 in F(ab')2 form [MRK16-F(ab')2], which recognizes P-glycoprotein (P-gp). The relative resistance index to various drugs was calculated by dividing the 50% growth inhibitory concentration (IC50) of the test cell line by IC50 of K562, which was the negative control in the antibody experiment. MRK16-F(ab')2 reacted with four cell lines, K562/ADM, KYO-1, HEL and CMK, which had relative resistance index values of 2 or more to vincristine (VCR), vindesine, vinblastine, ADM, daunorubicin, mitoxantrone (MIT), etoposide (VP-16) and actinomycin-D (ACT-D). The level of resistance to VCR and ADM in these cell lines decreased significantly in the presence of 10 microM verapamil in vitro. Significant expression of mRNA of P-gp gene was also detected in K562/ADM, KYO-1 and HEL. MRK16-F(ab')2 did not react with 36 other cell lines. Among them, three cell lines, PL-21, P31/FUJ and KOPM-28, had relative resistance index values of 2 or more to anthracyclines, MIT and VP-16, but not to vinca alkaloids or ACT-D. The level of ADM-resistance in these cell lines did not decrease significantly in the presence of 10 microM verapamil. Five cell lines, ATL-1K, HL-60, KMOE-2, ML-1 and U266, had relative resistance index values of 2 or more to some of the drugs, but not to the others, and 19 other cell lines did not. These results indicate that the reactivity of MRK16-F(ab')2 correlates with a relative resistance index of 2 or more to all these drugs in cultured human leukemia and lymphoma cell lines.     

Suppression of human hepatoma growth in vivo by a monoclonal antibody against a Mr 45,000 protein

The monoclonal antibody T2-2 was originally raised against the colorectal carcinoma cell line LS174T and was found to bind to several other human carcinomas, including hepatoma and ovarian cancer. The goal of this study was to investigate the antitumor activity of mAb T2-2 in human tumor models and further characterize the antigen. mAb T2-2 inhibited the growth of human hepatocellular cell line SMMC 7721 in vivo and in vitro. Western blot analysis revealed that this mAb recognizes an unique Mr 45,000 band from tissue extracts of human hepatocellular carcinoma (HCC), which localizes to the cell periphery. In vitro cell assays indicate that T2-2 decreases cell adhesion to laminin, implying the functional role of T2-2 antigen in cell-matrix interaction and cell migration.     

The Thomsen-Friedenreich antigen on human urothelial cell lines detectable by peanut lectin and monoclonal antibody raised against human glycophorin A

The Thomsen-Friedenreich (TF) antigen is a cryptic disaccharide structure on human erythrocytes which can be exposed by neuraminidase treatment and which is supposed to be expressed in an unmasked form on some carcinoma cells. For its detection in addition to auto-, allo- and heteroantisera, PNA (peanut lectin) is being applied. In the present studies the mouse monoclonal antibody (MoAb) raised to asialoglycophorin from human erythrocytes was used. The MoAb 22.19 is of mouse IgM isotype and is specifically binding to beta-D Gal-1-3 alpha-D GalNAc. The human urothelial cell lines maintained and characterized earlier were analyzed using indirect immunofluorescence assays. Among the spectrum of cell lines tested, five out of six cell lines belonging to the transformation grade III category (invasive in vitro and tumorigenic in nude mice) expressed TF antigen. The relationship between expression of TF antigen and other earlier defined biological traits related to malignant phenotype is discussed.     

Detection of epoxide hydrolase in rat hepatoma cell lines and primary rat liver cells by immunoblotting

Rat epoxide hydrolase (EH) (EC 3.3.2.3) is elevated in cells of premalignant liver lesions, and variable EH activity has been reported for hepatocellular carcinomas. To facilitate detection of altered EH levels in liver cells, an immunoblotting method was devised. Rabbit antiserum specific for rat EH was prepared and used to detect EH extracted from suspensions of normal liver cells and from hepatoma cell lines. Compared with normal liver cells, 3 rat hepatoma cell lines, 7777, HTC and 17X, showed virtually undetectable EH levels by immunoblotting. The immunoblotting results rule out the possibility that very low EH enzymatic activity in the hepatoma cells results from production of normal amounts of non-functional enzyme protein.     

Identification of human acinar cell carcinoma by monoclonal antibody and in vitro differentiation

Methylnitrosourea (MNU)-induced carcinomas in organ-cultured human pancreas when injected into nude mice produced subcutaneous carcinomas none of which were recognizable as being of acinar cell origin. Both monoclonal antibody to acinar cell surface marker produced by hybridoma, and in vitro tumor cell differentiation were used to detect tumors of acinar cell origin. Only 1 out of 14 tumors, a highly undifferentiated carcinoma, proved to be of acinar origin. This tumor was composed of cells devoid of zymogen granules but with abundant acinar cell surface marker. The acinar origin of this tumor was also confirmed by its differentiative features after 7 weeks of culture.     

Modulation of c-myc expression by transforming growth factor beta 1 in human hepatoma cell lines

The effects of transforming growth factor beta 1 (TGF-beta 1) on cell proliferation of human hepatoma cell lines, PLC/PRF/5 and Mahlavu, were investigated under serum-free conditions. DNA synthesis was strongly inhibited in the PLC/PRF/5 cells by addition of TGF-beta 1 (0.5 to 4.0 ng/ml), but remained unchanged in the Mahlavu cells. Also the expression of c-myc mRNA was suppressed by the addition of TGF-beta 1 in the PLC/PRF/5 cells but not in the Mahlavu cells. These results indicate that TGF-beta 1 might regulate cell growth, in part, by modulating c-myc expression, although there is no direct proof that c-myc expression is really relevant to DNA synthesis mediated by TGF-beta 1.     

奥沙利铂对人肝癌细胞的放射增敏作用

目的：研究奥沙利铂（Ｌ-ＯＨＰ）对人肝癌ＳＭＭＣ-７７２１细胞的放射增敏作用。方法：实验分为单纯用药组及放疗＋药物组,采用ＭＴＴ法观察Ｌ-ＯＨＰ不同药物浓度与不同外放射剂量２４、４８、７２ｈ对人肝癌细胞ＳＭＭＣ-７７２１的抑制作用。计算细胞抑制率和增敏比,应用统计软件ＳＰＳＳ１１.５处理数据,运用方差分析和多元相关方法分析各因素对人肝癌细胞ＳＭＭＣ-７７２１的抑制作用以及各因素之间的交互作用。结果：生长抑制率与放疗剂量、Ｌ-ＯＨＰ浓度呈正相关,而时间因素与生长抑制率无相关性（Ｐ＞０.０５）。结论：在采用Ｌ-ＯＨＰ对肝癌进行放射增敏时,时间因素可忽略不计。当Ｌ ＯＨＰ浓度大于０.６２５ｍｇ／Ｌ,将可获得放疗增敏的效果。     

Inhibition of human melanoma cell growth in vitro by monoclonal anti-GD3-ganglioside antibody

Malignant melanoma cell growth in vitro was blocked by the monoclonal antibody R-24, which detects the disialoganglioside GD3 on melanoma cells. GD3 expression varies greatly in cultured human malignant melanoma cells. The level of ganglioside GD3 was measured by quantitative absorption tests. In our observations, six melanoma cell lines expressing high levels of GD3 on the cell surface showed growth inhibition and rounding up in the presence of R-24 antibody. Four melanoma cell lines with low levels of GD3 and seven nonmelanoma cell lines with no detectable GD3 remained unchanged in morphology and continued to grow. The data presented indicate that complement is not involved in the growth inhibition observed here. Because ganglioside GD3 was detected in all 16 tissue specimens of primary and metastatic human malignant melanoma examined by immunofluorescence tests, the possible relevance of this finding in vivo is discussed.     

Up-regulation of E-cadherin by an anti-epidermal growth factor receptor monoclonal antibody in lung cancer cell lines.

Many human epithelial carcinomas are characterized by the overexpression and constitutive activation of the epidermal growth factor receptor (EGF-R) via an autocrine signaling loop. We have investigated the effects of a ligand-blocking monoclonal antibody (mAb) against the EGF-R LA1 on selected parameters of human lung cancer cell lines (H322 and H661) and normal human bronchial epithelial (NHBE) cells. Using Western blot analysis, we show that H322 and NHBE cell lines express comparable levels of EGF-R/p170erbB-1. The LA1 mAb against EGF-R inhibits growth, induces differentiation to a more epithelial phenotype, reduces the constitutive activation of EGF-R, and upregulates epithelial cadherin glycoprotein expression in H322 and NHBE cells. In contrast, LA1 had no effect on either growth, differentiation, receptor tyrosine phosphorylation, or the expression of adhesion molecules in H661 cells, which is consistent with our finding that this cell line does not express detectable levels of EGF-R. These studies demonstrate that a blocking anti-EGF-R mAb can regulate proliferation, differentiation, and the expression of cell adhesion molecules in human bronchial epithelial cells. Our findings suggest possible therapeutic avenues for the treatment of invasive carcinomas via the blockade of EGF-R with antibodies.