Transplantation of putative preneoplastic hepatocytes of analbuminemic rats in the livers of Sprague-Dawley x analbuminemic hybrid rats

As the analbuminemia of analbuminemic rats (NAR) is inherited as a recessive trait, the livers of F1 hybrids of Sprague-Dawley X NAR (SD X NAR) retain the capability to produce albumin. We induced albumin-negative hyperplastic nodules in the livers of NAR, isolated the nodule cells and transplanted them in the livers of SD X NAR by infusion into the mesenteric vein. When the hosts were treated with dietary 2-acetylaminofluorene plus a partial hepatectomy, numerous albumin(-) nodules of donor origin were formed within the albumin(+) livers of the hosts. This system should be useful to analyze sequential events during hepatocarcinogenesis by using a genotypic marker.     

Differential proliferative response of gastric mucosa during carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in susceptible ACI rats, resistant Buffalo rats, and their hybrid F1 cross

The effect of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on the proliferative characteristics of the pyloric epithelium was investigated in ACI and Buffalo rats and their F1 rats, which are susceptible, resistant, and resistant, respectively, to gastric carcinogenesis by this chemical. After injection of bromodeoxyuridine (BrdUrd), DNA synthesizing cells in the pyloric epithelium were stained immunohistochemically with anti-BrdUrd antibody. The average number and range of distribution of cells labeled with BrdUrd in the pyloric glands were significantly larger in ACI rats than in Buffalo or F1 rats after administration of MNNG (83 micrograms/ml in the drinking water) for 2 or 16 weeks. In control rats given tap water for 2 weeks, there was no significant difference in these values in the three groups (Experiment 1). The distribution of cells that were labeled with [methyl-3H]MNNG in the pyloric epithelium was measured by histoautoradiography, and the distribution of cells double labeled with both [methyl-3H]MNNG and BrdUrd was also analyzed. Rats were given 83 micrograms/ml of MNNG in their drinking water for 2 weeks and then received [methyl-3H]MNNG by gavage and an injection of BrdUrd 2 and 1 h, respectively, before sacrifice. The average number of double labeled cells (i.e., replicating cells exposed to MNNG) was significantly larger in ACI rats than in Buffalo or F1 rats. In control rats given tap water without MNNG for 2 weeks, there was no significant difference in these values in the three groups (Experiment 2). Cells double labeled with [methyl-3H]MNNG and BrdUrd are considered to be cells with the potential to establish mutations (cell population at risk of MNNG-induced carcinogenesis). Our results show that, after MNNG treatment, the size of this cell population is larger in susceptible ACI rats than in resistant Buffalo and F1 rats. Thus, differential responses of the gastric mucosa to MNNG may be a key factor in the difference of susceptibility to gastric carcinogenesis between ACI and Buffalo rats.     

Tumorigenicity of nasopharyngeal carcinoma hybrid cell line

The spontaneous production of Epstein-Barr virus (EBV) and tumorigenicity in the BALB/c mutant nude mouse were studied with the use of the following 4 cell lines derived from the human nasopharynx: a) Ad-AH, an 8-azahypoxanthine-resistant epithelioid cell line; b) A2L, an EBV-carrying lymphoblastoid cell line; c) A2L/AH, an EBV-carrying epithelioid hybrid cell line established by fusion of Ad-AH cells with A2L cells; and d) NPC-KT, an EBV-carrying epithelioid hybrid cell line established by fusion of Ad-AH cells with nasopharyngeal carcinoma (NPC) primary culture cells. The NPC-KT hybrid cell line was the only cell line to produce EBV antigens of the lytic cycle and virus particles. Cloning efficiency in agarose was clearly related to tumorigenicity in nude mice. Especially high, frequent tumor formation was observed in the heterotransplantation of NPC-KT hybrid cells that presented poorly differentiated carcinoma, and the tumor cells were positive for EBV-associated nuclear antigen. These NPC-KT hybrid cells maintained the characteristics of a histologic type of NPC tumor cells. Thus experimental systems of NPC were established in vitro and in vivo by the application of NPC-KT hybrid cells to NPC model cells.     

Pathology of human-mouse somatic cell hybrid tumors.

Somatic cell hybrids between mouse peritoneal macrophages and simian virus 40-transformed human cells injected sc into nude mice resulted in a formation of tumors with two distinct growth rates and growth patterns: 1) rapid growing, irregularly circumscribed, with necrotic foci and prominent vascular channels lined by tumor cells and 2) slow growing, small, well-circumscribed, and nonvascular. Individual tumor cells were ultrastructurally classified as undifferentiated mesenchymal cells indistinguishable within these two tumor types. Characteristics of each tumor type were retained during subsequent passages in nude mice.     

The use of hybrid cells in immunotherapy.

HARRIS et. al. isolated somatic hybrid cells (A9/SEWA) between polyoma-induced tumor and mouse fibroblast cell lines. Although these hybrid cells were no longer tumorigenic, we found that their immunogenicity was conserved. It therefore seemed to us that these antigenic, non transplantable, living cells would be an ideal tool for immunotherapy experiments. In our first experiments we assessed the immunoprotection afforded by A9/SEWA cells in both the SEWA tumor/A.SW mouse and C3HPy/C3H mouse systems. However, the efficiency of immunization with hybrid cells is dependent on the stability of the cells, especially in respect to the expression of the TATA. So we also tried to evaluate the immunogenicity as a function of the number of subcultures undergone by the hybrid line. In both systems, the immunogenicity was very good in the early subcultures but, in the C3HPy tumor/C3H mouse system, a loss of immunogenicity was observed as the number of subcultures increased. Thus any clinical application or immunization by hybrid cells would necessitate the verification of the presence of the tumor-associated antigens at each subculture. We are at present experimenting with various in vitro techniques for detection of the expression of these antigens.     

Activation of Epstein-Barr virus in hybrid cells.

Human-primate hybrid cell lines were established by fusion of African green monkey kidney cells (VERO) with lymphoblastoid cells from patients with infectious mononucleosis (IM)(IMK101) and from Burkitt's lymphoma culture (HR1K). Both Epstein-Barr virus (EBV)-specific antigens and EBV particle-containing cells increased in the hybrid lines (IMK1-1/VERO,HR1K/VERO). Treatment of the hybrids with 5-bromodeoxyuridine induced more antigen-positive and more virus-containing cells. EBV could be activated from IM lymphoblastoid cells by fusion of the lymphoblastoid cells with the VERO cells. The increase of viral antigens and virus particles may have been due to the cellular interaction between VERO cells and the lymphoblastoid cells or to a possible derepressor supplied by the VERO component of the hybrid. Virus derived from the HR1K cell line was replicated in the human-primate hybrid, but further investigation may be necessary to determine if it was identical to the EBV derived from the human cell line.     

Model based hybrid analysis of cancer patient survival

In many cancer registries, registration of new cases is somewhat less up-to-date than mortality follow-up. In such situations, hybrid analysis, a combination of cohort and period analysis, rather than 'pure' period analysis has been proposed to derive up-to-date survival estimates. We evaluate application and adaptation of a modelling strategy that has recently been introduced to enhance precision of period survival estimates, to 'hybrid type of data'. Using data from the Finnish Cancer Registry, we show that modelling again strongly increases precision of survival estimates. Furthermore, special models adapted to the hybrid type of data are shown to provide even more precise and, in a clear majority of cases, also more valid predictions of survival of recently diagnosed patients than models ignoring the hybrid type of data. Finally, we show that model-based estimation of and testing for recent trends may give different answers if period rather than hybrid modelling is used for hybrid type of registry data. We conclude that modelling is useful for both hybrid and period analyses of cancer survival, but the different data structure needs to be taken into account in the set-up of models.     

急性杂合型白血病的超微结构和电镜诊断

 目的 回顾性分析急性杂合型白血病（HAL）细胞的超微结构特点。方法 选择根据欧洲白血病协作组标准确定诊断的15例HAL,电镜观察HAL细胞组成和超微结构及电镜组化（MPO）结果。结果 15例HAL中,电镜诊断与免疫表型诊断相符5例（3例双表型,2例双克隆型）;疑似HAL诊断2例;考虑ALL诊断5例,M5a 2例;M4b 1例。结论 大部分双表型HAL细胞超微结构表现淋系特点,少数表现单核细胞特点或非特异性。电镜对双克隆型及MPO阳性的双表型HAL诊断容易,难以对MPO阴性的双表型HAL与ALL进行结构鉴别;少数病例容易误诊为M5a。     

12例急性混合细胞白血病的诊断与疗效分析

目的分析急性混合细胞白血病（HAL）的临床和实验室特征以及疗效和预后。方法根据骨髓细胞形态学、化学染色和免疫表型结果诊断HAL,评价疗效及影响疗效的相关因素。结果12例HAL临床表现可有发热、淋巴结肿大、脾大、肝大、睾丸浸润等,所有患者骨髓增生明显活跃,近半数患者属高白细胞白血病。进行免疫表型检测者11例,B—Ly^＋／My^＋双表型8例、T—Lv^＋／My^＋双表型2例、B＋T—Ly^＋／My^＋型1例。诱导化疗的总CR率64％,6例以兼顾粒、淋二系的方案治疗后全部CR,有4例巩固强化治疗后持续缓解,平均无病生存已19（16～24）个月。结论HAL属特殊类型的白血病,其诊断有赖于对细胞形态学、化学染色和免疫分型的综合判断。对HAL的治疗应该给予兼顾粒、淋二系的诱导和巩固化疗方案。但长期疗效的评价还有待进一步观察。     

A novel hybrid peptide targeting EGFR-expressing cancers

Several potential molecular-targeted anticancer drugs focus on the inhibition of receptor tyrosine kinase and tumour growth, but these tyrosine kinase inhibitors (TKI) have been reported that the mutations of kinase-related signal molecule genes in cancer cells lead to the drug resistance. To overcome this issue, we have designed a novel targeting anticancer ‘hybrid-peptide’ EGFR-lytic peptide, in which epidermal growth factor receptor (EGFR) binding peptide is conjugated with a newly designed lytic-type peptide containing cationic-rich amino acids that disintegrates the cell membrane to kill cancer cells. In this report, cytotoxic activity of EGFR-lytic peptide was investigated in various human cancer and normal cell lines. It was found that the resulting conformational change in the novel lytic peptide enabled it to bind selectively to the membrane of cancer cells, and due to its acquired synergistic action, hybrid peptide demonstrated selective destruction of cancer cells as swiftly as 10 min after exposure. Treatment with EGFR-lytic peptide exerted a sufficient in vitro cytotoxic activity against TKI-resistant cancer cells with K-ras mutations. Moreover, in vivo analyses revealed that this peptide displayed significant antitumour activity in mouse xenograft models of both human K-ras mutation negative and positive cancers. Thus, hybrid peptide can be a unique and powerful tool for a new cancer-targeted therapy.