D5hC50X10: Saturn-like fullerene derivatives (X=F, Cl, Br)

Based on the recently reported D(5h) C(50), the geometries and stabilities of its Saturn-like derivatives C(50)X(10) (X=F, Cl, Br) have been investigated by DFT method. Compared with C(50), the equatorial carbon atoms in C(50)X(10) have been saturated by halogens and change to sp(3) hybridization to release the large angle strain. Because the equatorial carbon atoms have been taken out of the pi system by the halogens "ring," the C(50)X(10) system has been split into two well-delocalized conjugated annulene subunits, and then the electronic stabilization has been enhanced.

A gene (pks2) encoding a putative 6-methylsalicylic acid synthase from Glarea lozoyensis

A gene that encodes for a polyketide synthase (PKS) was cloned from the fungus Glarea lozoyensis and characterized. The gene (pks2) consists of four exons interrupted by three introns of 51, 59, and 65 bp, which are clustered at the 5' end. Its predicted product is a 1791-amino-acid protein containing five catalytic motifs typical of fungal PKSs, including a beta-ketosynthase, an acyltransferase, a dehydratase, a beta-ketoacyl reductase, and an acyl carrier region. The gene is transcribed from an initiation site located 375 bp upstream of the translational start codon and extends to a transcriptional termination site 244 bp downstream of the translational stop codon. The gene function is not required for either vegetative growth of G. lozoyensis or for production of pneumocandin, as shown by Agrobacterium-mediated pks2 gene disruption. Previously reported cluster analysis of ketosynthase motifs from 37 fungal polyketide synthases had grouped the Pks2p from G. lozoyensis with PKSs involved in the biosynthesis of 6-methylsalicylic acid. To verify the function of the gene, it was transferred into Aspergillus nidulans under the control of the trpC promoter. 5'-and 3'-RACE experiments confirmed that it was transcribed in the heterologous host, and was associated with the synthesis of a compound identified as 6-methylsalicylic acid by NMR and mass spectrometry. In G. lozoyensis, pks2 is flanked by a gene that encodes a putative drug resistance efflux pump. The Aspergillus pks2 transformants, which were arginine prototrophs, also exhibited precocious pigmentation and accumulated a benzophenone that appeared to be a precursor of emericellin (variecoxanthone B), a known product of A. nidulans. The buildup of the benzophenone may be related to the use of an alternative splice site for the removal of intron 1 of the pks2 transcript in the heterologous host.

Dynamics of photogenerated polarons in conjugated polymers

Within a tight-binding electron-phonon interacting model, we investigate the dynamics of photoexcitations to address the generation mechanism of charged polarons in conjugated polymers by using a nonadiabatic evolution method. Besides the neutral polaron exciton which is well known, we identify a novel product of lattice dynamic relaxation from the photoexcited states in a few hundreds of femtoseconds, which is a mixed state composed of both charged polarons and neutral excitons. Our results show that the charged polarons are generated directly with a yield of about 25%, which is independent of the excitation energies, in good agreement with results from experiments. Effects of the conjugation length are also discussed.

Efficient disruption of a polyketide synthase gene ( pks1) required for melanin synthesis through Agrobacterium-mediated transformation of Glarea lozoyensis

Glarea lozoyensis produces pneumocandin B(0), a potent inhibitor of fungal glucan synthesis. This industrially important filamentous fungus is slow-growing, is very darkly pigmented, and has not been easy to manipulate genetically. Using a PCR strategy to survey the G. lozoyensis genome for polyketide synthase (PKS) genes, we have identified pks1, a gene that consists of five exons interrupted by four introns of 56, 400, 50 and 341 bp. It encodes a 2124-amino acid protein with five catalytic modules: ketosynthase, acyltransferase, two acyl carrier sites, and thioesterase/Claisen cyclase. The transcriptional initiation and termination sites were found 43 bp upstream of the translational start codon and 295 bp downstream of the translational stop codon, respectively. Cluster analysis of 37 fungal ketosynthase modules grouped the Pks1p with PKSs involved in the biosynthesis of 1,8-dihydroxynaphthalene melanin. Disruption of pks1 yielded knockout mutants that displayed an albino phenotype, suggesting that pks1 encodes a tetrahydroxynaphthalene synthase. Gene replacement was achieved by Agrobacterium-mediated transformation, which proved to be simple and efficient. Loss of pigmentation occurred in more than half the transformants, and examination of six non-pigmented transformants showed that the functional genomic copy of the pks1 gene had been replaced by the disruption cassette in each case. A putative 1215-bp ORF (dsg) devoid of introns was present downstream from pks1. BLAST analysis of the 405-amino acid sequence of its predicted product showed a high degree of similarity with Zn(II)(2)Cys(6) binuclear cluster DNA-binding proteins, a class of fungal transcription factors involved in the regulation of polyketide production and other pathways.

Status of trace elements in paddy soil and sediment in Taihu Lake region

Thirteen paddy soil profiles and river sediments which are sources of irrigation water were collected around the Taihu Lake, and the trace elements were estimated. The content of La and Ce in paddy soil and sediment were 39.3 and 68.6 mg/kg soil and 36.9 and 65.1 mg/kg soil, being within the range of background values. The values for Pb, Cu, Ni, Cr, Co, Mn, Zn, Se in paddy soil were 23.3, 27.8, 25.5, 63.5, 10.2, 386, 68.7 and 0.25 mg/kg soil respectively, all below the national permission level. There was a decline of Zn in paddy soil. Some of the river sediments were seriously polluted. The river in Yangjin site was most contaminated with 5.47 g Cu/kg and 7.4 g Zn/kg. The high concentration of Pb and Ni also was observed in this sediment. River in Weitang, Huashi, Xinzhuang and Meiyan were contaminated with Pb, Cu and Ni to some extent. Zn, Cu and Pb were the main pollutants in present experiment sites. The fast development of village/township industries have caused severe environmental pollution in the Taihu Lake region, especially irrigation river sediments. Se content in plant and seed was 0.04 and 0.03 mg/kg respectively, showed Se-deficiency in paddy soil in the Taihu Lake region.

[Technical causes of false and inferior species appearing in Chinese medicinal materials markets]

The result indicated that technical causes of false and inferior appearing in the Chinese medicinal materials markets consisted of two respects essentially. First, the men who violated the law and committed a crime used certain weak link existing in quantity analysis of country's medicinal standard. Second, it is difficult that basic units managing and using drug implement effective technical supervision.

[The status quo survey of false and inferior species in Chinese medicinal materials market in Hubei Province]

By taking a sample, unqualified varieties were investigated found in Chinese medicinal material examinatorial work near twenty years of six regional level and three countrylish level institutes for drug control and one comprehensive level-three grade-A hospital. By mail, false and inferior species and their origin of Chinese medicinal material were investigated found by sixteen institutes for drug control near ten years in Hubei province. 539 kinds of adulterants (750 cases) including 24 toxic species were found in above-mentioned investigations. Fales and inferior species are rampant in minority regions, which threatens people's health severely. It is urgent for supervising department to gorem the condition strictly.

[The influence of somatostatin 14 on the proliferation of human retroocular fibroblasts]

OBJECTIVE

To elucidate the possible mechanism of Somatostatin 14 in the treatment of Graves' ophthalmopathy, thus providing laboratory data with the intent to underpin therapeutic developments.

METHODS

The human retro-ocular fibroblasts (HROFb) was cultured and MTT colorimetry assay was used to determine the proliferation of HROFb.

RESULTS

MTT colorimetry assay could precisely reflect the proliferation of HROFb. The absorbance was directly proportional to the numbers of the cells (r = 0.996, P < 0.001). Somatostatin 14 could enhance the cell proliferation percentage at lower levels (< 25 nmol/L) and inhibit that at higher levels (> 25 nmol/L). The cell proliferation correlated positively to Somatostatin 14 levels significantly (r = -0.9054, P < 0.001).

CONCLUSION

Somatostatin 14 has a dual effect on HROFb.

Microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide

In the present study, a new microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide technique has been developed. The results show that microwave irradiation can dehydrate penicillin G sulfoxide from a water content of 14-26 to below 0.5% in 40-60 min in N2 or air. After washing with ethyl acetate to remove impurities and residual water, the penicillin G sulfoxide can be used to synthesize cephalosporanic acid. The recovery of cephalosporanic acid was equal to and the purity of cephalosporanic acid was higher by 2% than that of the current dehydration technique. FTIR spectroscopy was used to study the process of microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide.

[The effects of leptin on proliferation and function of human osteoblast]

OBJECTIVE

To observe the effect of leptin on osteoblast.

METHODS

Human osteoblast primary culture was carried out, and the morphology and function of osteoblast were observed. The effects of different levels of leptin on osteoblast in different days were assessed by MTT colorimetry. Osteocalcin production was measured also.

RESULTS

Human osteoblasts were fusiform in shape and were positive for alkaline phosphatase by histochemical staining, positive for osteocalcin by immunofluorescence staining, and positive by Alizarin Reds staining after mineralized upon supplementation with ascorbate and beta-glycerophosphate. On the first, second and third days, the proliferation of osteoblast, cultured with different concentrations of leptin, had no changes. The leptin-stimulated synthesis of osteocalcin of cells was found to be dose-dependent (P < 0.05), but not time-dependent (P > 0.05).

CONCLUSION

The above data indicated that there were no evidences for the effects of leptin on the proliferation of human osteoblast, but leptin could enhance the function of human osteoblast.

A highly metastatic Lewis lung carcinoma orthotopic green fluorescent protein model

The Lewis lung carcinoma has been widely used for many important studies. However, the subcutaneous transplant or orthotopic cell-suspension injection models have not allowed the expression of its full metastatic potential. A powerful new highly metastatic model of the widely-used Lewis lung carcinoma is reported here using surgical orthotopic implantation (SOI) of tumor fragments and enhanced green fluorescent protein (GFP) transduction of the tumor cells. To achieve this goal, we first developed in vitro a stable high-expression GFP transductant of the Lewis lung carcinoma with the pLEIN retroviral expression vector containing the enhanced Aequorea victoria GFP gene. Stable high-level expression of GFP was found maintained in vivo in subcutaneously-growing Lewis lung tumors. The in vivo GFP-expressing tumors were harvested and implanted as tissue fragments by SOI in the right lung of additional nude mice. This model resulted in rapid orthotopic growth and extensive metastasis visualized by GFP-expression. 100% of the animals had metastases on the ipsilateral diaphragmatic surface, contralateral diaphragmatic surface, contralateral lung parenchima, and in mediastinal lymph nodes. Heart metastases were visualized in 40%, and brain metastases were visualized in 30% of the SOI animals. Mice developed signs of respiratory distress between 10-15 days post-tumor implantation and were sacrificed. The use of GFP-transduced Lewis lung carcinoma transplanted by SOI reveals for the first time the high malignancy of this tumor and provides an important useful model for metastasis, angiogenesis and therapeutic studies.

Efficacy of intra-hepatectomy 5-FU on recurrence and metastasis of human hepatocellular carcinoma in nude mice

A novel intra-operative chemotherapy nude mouse model for human hepatocellular carcinoma (HCC) has been developed. Intra-peritoneal (i.p.) administration of 5-fluorouracil (5-FU) was begun 2 hr before hepatic resection of HCC and then continued post-operatively for 4 consecutive days. This regime, termed intra-hepatectomy chemotherapy (IHC), significantly prolonged animal survival compared with pre-operative 5-FU, neoadjuvant therapy, 5-FU post-operative adjuvant therapy, surgery alone, 5-FU without surgery, and the untreated control. The median survival of the intra-operative 5-FU-treated group was 127 days compared with 78 days for the neoadjuvantly-treated animals and 53 days for the control group (p<0.006). When all animals with neoadjuvant 5-FU treatment had died, 60% of the animals in the IHC group were still alive (p<0.011). Survival of all other treatment groups, including 5-FU without surgery, surgery alone, and adjuvant post-operative chemotherapy, was not significantly different from the untreated control group. Five animals in the IHC group were free of tumor when sacrificed at day 150 post-surgically. While 100% of animals in the control group had lymph nodes draining the liver involved with metastases, only 20% of animals in the IHC group had lymph node metastases. These data suggested that IHC therapy increased survival by preventing metastases of cancer cells not removed in the liver resection procedure. The results of this study indicate that IHC therapy for resection of HCC should be investigated clinically.

Comparison of three approaches to doxorubicin therapy: free doxorubicin, liposomal doxorubicin, and beta-glucuronidase-activated prodrug (HMR 1826)

BACKGROUND

Three approaches to doxorubicin therapy are directly compared: free doxorubicin, liposomal doxorubicin and beta-glucuronidase-activated prodrug (HMR 1826).

MATERIALS AND METHODS

The optimal dose of HMR 1826 was determined to be 200 mg/kg once a week and subsequent studies were carried out comparing HMR 1826 at 200 mg/kg 1x/wk, liposomal doxorubicin (Doxil) at 9 mg/kg 1x/wk and free doxorubicin at 7 mg/kg 1x/wk in seven different human tumor xenograft models.

RESULTS

All three forms of doxorubicin inhibited tumor growth with similar efficacy in each of the tumor models with the exception of MDA-MB-231 tumor xenografts, which were resistant to free doxorubicin but sensitive to Doxil and HMR 1826. Overall less weight loss was observed with HMR 1826 treatment.

CONCLUSIONS

The efficacy of HMR 1826 is equal to or better than that of doxorubicin and Doxil at a safe dose and schedule, indicating that the beta-glucuronidase activated prodrug approach is safe and effective.

Antimetastatic intraoperative chemotherapy of human colon tumors in the livers of nude mice

We have developed a new antimetastatic chemotherapeutic strategy for combination with hepatic resection of human colon cancers in a high-metastasis nude mouse model. The new procedure involves i.p. administration of 5-fluorouracil (5-FU) 2 h before hepatic resection of the human colon tumors, with therapy continued postoperatively for 4 consecutive days. We termed this strategy neo-neoadjuvant chemotherapy. The regime significantly prolonged animal survival compared with preoperative 5-FU neoadjuvant therapy, 5-FU postoperative adjuvant therapy, surgery alone, 5-FU without surgery, or the untreated control. The median survival of neo-neoadjuvant i.p. 5-FU-treated group was 81 days, compared with 27 days for the control group (P < 0.009). The median survival of animals in the neoadjuvant group was 37 days (P < 0.021 compared with the control group). There was also a significant difference between the median survival of neo-neoadjuvant, and the neoadjuvant group (P < 0.031). When all animals in the control group had died, 70% of animals with neo-neoadjuvant and 60% of animals with neoadjuvant 5-FU were still alive (P < 0.003 and P < 0.011, respectively). When all animals with neoadjuvant 5-FU treatment had died, 70% of animals with neo-neoadjuvant treatment were still alive (P < 0.003). Survival of all other treatment groups, including 5-FU without surgery, surgery alone, and adjuvant postoperative chemotherapy, was not significantly different from the untreated control group. Two animals in the neo-neoadjuvant group were free of tumors when sacrificed at days 154 and 165 post surgery. Whereas 100% of animals in the control, 90% in the 5-FU alone, 70% in the surgery alone, 60% in the 5-FU adjuvant, and 40% in the neoadjuvant groups had metastases in the lymph nodes draining the liver, only 10% of animals in the neo-neoadjuvant group had metastases. These data suggest that the neo-neoadjuvant therapy increased survival by preventing metastasis of cancer cells not removed in the liver resection procedure. The results of this study indicate that the neo-neoadjuvant treatment strategy for resection of colon cancer liver metastasis should be explored clinically.

Minimal liver resection strongly stimulates the growth of human colon cancer in the liver of nude mice

Partial hepatectomy has been widely employed in clinical practice as the therapy of choice for primary and metastatic liver tumors. However, the recurrence rate after the treatment remains high, which is most likely due to the growth of residual microscopic lesions. Previous studies in murine models demonstrated that a 70% hepatectomy significantly accelerated the growth of ectopically implanted tumors. In this study, we reported the effect of partial hepatectomy on the growth of two human colon cancers (Co-3 and AC3603) implanted in the liver of nude mice using the technique of surgical implantation of histologically intact tumor tissue. Our results showed a dramatic acceleration of tumor growth following 30% partial hepatectomy, which resembles clinical procedures. Tumor volumes were assessed with calipers on day-15 by abdominal palpation and on day-30 at autopsy by direct measurement. For both Co-3 and AC3603, tumor volumes in the hepatectomized animals were significantly larger than the control at the above two time points (P < 0.001). The results demonstrate the stimulating effect of partial hepatectomy directly on the tumor growth in the liver, in contrast to previous studies on ectopic tumors. Furthermore, since conservative partial hepatectomy (30%) is normally used in clinical practice for surgical treatment of liver metastasis, the animal models presented here should be useful for the clinical investigation of the high recurrence rate of liver metastasis following partial hepatectomy.

[Effects of homoharringtonine on proliferation of human retro-ocular fibroblasts]

This is a study amied at the effects of homoharringtonine on the proliferation of human retro-ocular fibroblasts. The human retroocular fibroblasts (HROFb) were cultured and MTT colorimetry assay was used to determine the proliferation of HROFb. The influence of homoharringtonine on the proliferation of HROFb was observed in vitro. The results showed that MTT colorimetry assay could precisely reflect the proliferation of HROFb. The absorbance was directly proportional to the number of the cells (r = 0.996, P < 0.001). The proliferation of HROFb was inhibited by the homoharringtonine and the cell proliferation percentage was correlated positively to the homoharringtonine level (r = 0.6932, P < 0.001).

A nude mouse model of massive liver and lymph node metastasis of human colon cancer

Liver and lymph nodes metastasis are the main causes of treatment failure for advanced colon cancer. However, currently-available animal models of human colon cancer do not demonstrate sufficient metastasis to represent highly malignant colon cancer that extensively metastasizes to these sites. A liver metastasis from a patient with highly malignant, poorly differentiated adenocarcinoma of the colon was established in nude mice by surgical orthotopic implantation to the mouse colon. The human origin of the tumor growing in nude mice was confirmed by in situ hybridization of human DNA. After 20 passages from the first implantation, massive liver and lymph nodes metastasis, occurred in 100% of the transplanted animals. Lymph nodes metastasis were found at the sites of lymph node drainage of the liver: celiac, portal and mediastinal lymph nodes. However no mesenteric and retroperitoneal nodes or lung tissue metastases were observed. Our data suggest that the mediastinal, celiac and hepatic lymph nodes metastases are derived form the liver metastasis, confirming the concept of metastasis of metastases or "remetastasis" of colon cancer.

Survival efficacy of the combination of the methioninase gene and methioninase in a lung cancer orthotopic model

We have previously demonstrated the antitumor efficacy of recombinant methioninase (rMETase) derived from Pseudomonas putida. To enhance the efficacy of rMETase, we have constructed the pLGFP-METSN retrovirus encoding the P. putida methioninase (MET) gene fused with the green fluorescent protein (GFP) gene. pLGFP-METSN or control vector pLGFPSN was introduced into the human lung cancer cell line H460. The methionine level of H460-GFP-MET cells was reduced to 33% of that of H460-GFP cells. rMETase (0.08 U/mL) in the medium resulted in 10% survival of H460-GFP-MET cells compared with untreated cells in vitro. In contrast, rMETase-treated H460-GFP cells survived at 90% of control. Tissue fragments harvested from subcutaneous tumors of H460-GFP-MET or H460-MET were implanted by surgical orthotopic implantation into the lungs of nude mice. A suboptimal dose of rMETase was administered intraperitoneally daily to mice in each group. Overall survival of rMETase-treated animals with H460-GFP-MET tumors was significantly longer than either rMETase-treated or -untreated animals with H460-GFP tumors (P < .05 in log-rank test). In two repeat experiments, rMETase-treated animals with H460-GFP-MET tumors had a 30-day survival of 80% and 83%, respectively. Untreated animals with H460-GFP-MET tumors had a 30-day survival of 40% and 58%, respectively. rMETase-treated animals with H460-GFP tumors had a 30-day survival of 0% and 33%, respectively. Untreated animals with H460-GFP tumors had a 30-day survival of 0% and 33%, respectively. The retrovirus-mediated gene transfer of METase decreased the intracellular methionine level of tumor cells and consequently enhanced the efficacy of treatment with the rMETase protein. We have thus demonstrated a new strategy of combination tumor therapy with the gene and gene product of MET.

Genetically fluorescent melanoma bone and organ metastasis models

We report here the establishment and metastatic properties of bright, highly stable, green fluorescent protein (GFP) expression transductants of the B16 mouse malignant melanoma cell line and the LOX human melanoma line. The highly fluorescent malignant melanoma cell lines allowed the visualization of skeletal and multiorgan metastases after i.v. injection of B16 cells in C57BL/6 mice and intradermal injection of LOX cells in nude mice. The melanoma cell lines were transduced with the pLEIN expression retroviral vector containing the GFP and neomycin resistance genes. Stable B16F0 and LOX clones expressing high levels of GFP were selected stepwise in vitro in levels of G418 of up to 800 microg/ml. Extensive bone and bone marrow metastases of B16F0 were visualized by GFP expression when the animals were sacrificed 3 weeks after cell implantation. Metastases for both cell lines were visualized in many organs, including the brain, lung, pleural membrane, liver, kidney, adrenal gland, lymph nodes, skeleton, muscle, and skin by GFP fluorescence. This is the first observation of experimental skeletal metastases of melanoma, which was made possible by GFP expression. These models should facilitate future studies of the mechanism and therapy of bone and multiorgan metastasis of melanoma.

Efficacy of recombinant methioninase in combination with cisplatin on human colon tumors in nude mice

The present treatment of colon cancer is based on 5-fluorouracil (5-FU). Despite promising results of combining leucovorin or levamisole with 5-FU, the 5-year survival rate of patients with advanced colon cancer has not increased significantly. Colon tumors in vitro have been shown previously to have an elevated requirement for methionine, suggesting a new therapeutic target. In this study, targeting the methionine dependence of colon tumors is effected by recombinant methioninase (rMETase), alone and in combination with cisplatin (CDDP). In vitro results demonstrated that CDDP and rMETase act synergistically on the human colon cancer cell line SW 620, with a combination index (CI) of 0.45, as well as on the human colon cancer cell line Colo 205 with a CI of 0.7. Human colon cancer lines HCT 15, HT 29, Colo 205, and SW 620 growing in nude mice were treated with rMETase to determine an effective dose for depletion of tumor methionine. rMETase at 15 units/g/day for 5 days depleted tumor methionine in all four tumor types to approximately 30% of untreated control. rMETase alone arrested growth of HCT 15 and HT29 in nude mice for 1 week after treatment termination. Colo 205 and SW 620 were partially arrested by rMETase. However, CDDP in combination with rMETase resulted in tumor regression of Colo 205 and growth arrest of SW 620 in nude mice. The ratio of the treated:control group (T:C) tumor weights for Colo 205 was 8% when CDDP was given on day-5, followed by treatment on days 5-9 with rMETase. This treatment schedule resulted in two of the six animals having no detectable tumor when the experiment was terminated on day 16. SW620 was resistant to CDDP alone and only partially sensitive to rMETase alone. However, when SW 620 was treated with rMETase from days-5 to -9 and CDDP on day-5, tumor growth was arrested. The results demonstrate that rMETase used simultaneously in combination with CDDP had significant antitumor efficacy in colon cancer in vitro and in vivo. The data suggest a novel and promising therapeutic approach by targeting the elevated methionine dependence of colon cancer.

High-malignancy orthotopic nude mouse model of human prostate cancer LNCaP

BACKGROUND

An animal model of human prostate cancer LNCaP demonstrating high rates of spontaneous metastasis from the orthotopic site after tumor implantation would be very valuable for mechanistic and drug discovery studies. We previously developed microsurgical techniques to implant histologically intact tumor tissues orthotopically in nude mice in order to develop high metastatic mouse models of human cancer.

METHODS

Intact tissue of the androgen-dependent human prostate cancer cell line, LNCaP, was implanted on the ventral lateral lobes of the prostate gland by surgical orthotopic implantation (SOI) in a series of 20 nude mice. Mice were autopsied, and histopathological examination of primary tumors and relevant organs was done to identify and quantitate micrometastasis.

RESULTS

Eighteen of 20 animals transplanted with LNCaP by SOI had tumor growth. Mean primary tumor weight in the prostate was 9.24 g at time of necropsy. Sixty-one percent of the transplanted animals had lymph node metastasis. Forty-four percent had lung metastasis. Mean survival time was 72 days, indicating a high degree of malignancy of the tumor.

CONCLUSIONS

The extensive and widespread lung metastasis as well as lymph node metastasis following orthotopic implantation of LNCaP in nude mice and the short survival time provide a high-malignancy nude model of the LNCaP human prostate tumor.

Development of a high metastatic orthotopic model of human renal cell carcinoma in nude mice: benefits of fragment implantation compared to cell-suspension injection

In this study we compared the metastatic rate of human renal cell carcinoma SN12C in two orthotopic nude mouse models: surgical orthotopic implantation (SOI) of histologically intact tumor tissue and cellular orthotopic injection (COI) of cell suspensions in the kidney. The primary tumors resulting from SOI were larger and much more locally invasive than primary tumors resulting from COI. SOI generated higher metastatic expression than COI. The differences in metastatic rates in the involved organs (lung, liver, and mediastinal lymph nodes) were 2-3 fold higher in SOI compared to COI (P < 0.05). Median survival time in the SOI model was 40 days, which was significantly shorter than that of COI (68 days) (P < 0.001). Histological observation of the primary tumors from the SOI model demonstrated a much richer vascular network than the COI model. Lymph node and lung metastases were larger and more cellular in the SOI model compared to COI. We conclude that the tissue architecture of the implanted tumor tissue in the SOI model plays an important role in the initiation of primary tumor growth, invasion, and distant metastasis. This study directly demonstrates that the implantation of histologically intact tumor tissue orthotopically allows accurate expression of the clinical features of human renal cancer in nude mice. This model should be of value in cancer research and antimetastatic drug discovery for renal cancer, a currently very poorly responding malignancy.

An ultra-metastatic model of human colon cancer in nude mice

An ultra-high metastatic model of human colon cancer was developed in order to represent highly malignant patient disease for which there is no current model. Surgical orthotopic implantation (SOI) of a histologically intact liver metastasis fragment derived from a surgical specimen of a patient with metastatic colon cancer was initially implanted in the colon, liver and subcutaneously in nude mice. This tumor did not metastasize for the first 10 passages. At the eleventh passage, the tumor exhibited metastasis from the colon to the liver, spleen, and lymph nodes. At this time, two selective passages were carried out by transplanting resulting liver metastases in the nude mice to the colon of additional nude mice. After these two passages, the tumor became stably ultra-metastatic and was termed AC3488UM. One-hundred percent of mice transplanted with AC3488UM with SOI to the colon exhibited local growth, regional invasion, and spontaneous metastasis to the liver, lymph nodes, and spleen. While the maximum size of the primary tumor was 0.9 g, the metastatic liver was over 9 times the weight of the normal liver with the maximum weight of the metastatic liver over 12 g. Liver metastases were detected by the tenth day after transplantation in all animals. Half the animals died of metastatic tumor 25 days after transplantation. Histological characteristics of AC3488UM tumor were poorly differentiated adenocarcinoma of colon. Mutant p53 is expressed heterogeneously in the primary tumor and more homogeneously in the liver metastasis suggesting a possible role of p53 in the liver metastasis. The human origin of AC3488UM was confirmed by positive fluorescence staining for in situ hybridization of human DNA. The AC3488 human colon-tumor model with its ultra-high metastatic capability in each transplanted animal, short latency and a short median survival period is different from any known human colon cancer model and will be an important tool for the study of and development of new therapy for highly metastatic human colon cancer.

Efficacy of new platinum analog DPPE in an orthotopic nude mouse model of human colon cancer

A surgical orthotopic implantation (S.O.I.) model of the human colon cancer cell line Co-3 in nude mice was treated with two doses of the new platinum analogs {Pt(cis-dach) (DPPE).2NO3} and {Pt(trans-dach)(DPPE).2NO3}. The analogs were evaluated for antimetastatic efficacy in comparison to two doses of cisplatinum. Unlike the untreated control group, there were no mesenteric lymph node metastases in the groups treated with the high or low doses of both forms of new DPPE platinum analogs as well as cisplatinum-treated group. However, much more body-weight loss occurred in the cisplatinum-treated group than the DPPE-treated groups. The results obtained with SOI animal model of colon cancer demonstrated both cis- and trans-forms of DPPE had as strong an inhibitory effect on metastasis as that of cisplatinum, but with much less toxicity. Thus the new platinum analogs appears to have promising clinical potential.

[The hemodynamic changes after end-to-end anastomosis of the small arteries in rats]

The hemodynamics changes of the common carotid arteries in 10 SD rats were measured with a color doppler flowmetry in an attempt to define the changes resulting from end-to-end anastomosis. The left common carotid arteries were divided and followed by end-to-end anastomosis. The systolic mean peak velocities in the left arteries were measured at the proximal, distal and anastomotic sites and in the right intact arteries as well at 6, 12, 24, 48, 72 and 120 hours after repair. The percentage of area reduction at anastomosis was calculated from these data. The results indicated that the systolic mean peak velocity at the anastomotic sites was significantly increased as compared to the velocity at the proximal, distal and contralateral sites (P < 0.05). The velocity at the distal sites was significantly lower than that from the proximal and contralateral sites (P < 0.05), the mean percentage of the reduction was 33.18% and 33.33%, respectively. From 6 hours to 120 hours after anastomosis of arteries there was various degree of narrowing at the site of anastomosis. The mean per cent of stenosis was 42.48%. It was concluded that from 6 to 120 hours after end-to-end anastomosis of the small arteries, the velocity at the anastomotic site was increased as compared to the velocities at pre- and post-anastomotic sites. The increase of velocity at the site of anatomosis was caused by stenosis at the anastomosis.

[The connotation investigation of "female-male" in Chinese traditional medicine nomenclature]

The connotation investigation of "female-male" in nomenclature of Polygonum multiflorum Thunb, suggests that the female-male" in Chinese medicine nomenclature is generalized concept. It has three connotation, including correlation, relativity identity. It's concrete use of materialist dialectics in Chinese medicine.

Characterization of mat A-2, mat A-3 and deltamatA mating-type mutants of Neurospora crassa

The mating-type locus of Neurospora crassa regulates mating identity and entry into the sexual cycle. The mat A idiomorph encodes three genes, mat A-1, mat A-2, and mat A-3. Mutations in mat A-1 result in strains that have lost mating identity and vegetative incompatibility with mat a strains. A strain containing mutations in both mat A-2 and mat A-3 is able to mate, but forms few ascospores. In this study, we describe the isolation and characterization of a mutant deleted for mat (deltamatA), as well as mutants in either mat A-2 or mat A-3. The deltamatA strain is morphologically wild type during vegetative growth, but it is sterile and heterokaryon compatible with both mat A and mat a strains. The mat A-2 and mat A-3 mutants are also normal during vegetative growth, mate as a mat A strain, and produce abundant biparental asci in crosses with mat a, and are thus indistinguishable from a wild-type mat A strain. These data and the fact that the mat A-2 mat A-3 double mutant makes few asci with ascospores indicate that MAT A-2 and MAT A-3 are redundant and may function in the same pathway. Analysis of the expression of two genes (sdv-1 and sdv-4) in the various mat mutants suggests that the mat A polypeptides function in concert to regulate the expression of some sexual development genes.

Surgical orthotopic implantation allows high lung and lymph node metastatic expression of human prostate carcinoma cell line PC-3 in nude mice

BACKGROUND

Prostate cancer is the second leading cause of male death in the United States. When diagnosed, nearly half the cases have metastatic lesions. An animal model of human prostate cancer demonstrating spontaneous metastasis from the orthotopic site after tumor implantation should be of great help for us to understand the disease and to formulate treatment strategy. We report here a high metastatic model of human prostate cancer PC-3.

METHODS

We developed microsurgical techniques, termed surgical orthotopic implantation (SOI), to implant histologically intact tumor tissues orthotopically in immunodeficient mice. In this study intact tissue of the human prostate cancer cell line PC-3, harvested from a subcutaneous tumor in a nude mouse, was implanted to the ventral lateral lobes of the prostate gland in a series of nude mice. Mice were sacrificed when found moribund, and autopsy and histology were performed subsequently.

RESULTS

A high frequency of lymph node and lung metastasis was noted upon histological examination. The extensive and widespread lung metastasis following orthotopic implantation of PC-3 is, to the best of our knowledge, the first report in the literature.

CONCLUSIONS

In contrast to orthotopic injection of cell suspensions, no multiple metastatic cell selection was necessary after SOI for significant expression of the metastatic potential of PC-3. We conclude that the stromal tissue architecture maintained in the implanted tumor played a critical role in tumor growth and progression.

Polyethylene glycol conjugation of recombinant methioninase for cancer therapy

Recombinant methioninase (rMETase) is a homotetrameric pyridoxal 5'-phosphate enzyme of 172-kda molecular mass derived from Pseudomonas putida and cloned in Escherichia coli. rMETase has been found previously to be an effective, anti-tumor agent in vitro and in vivo. The enzyme targets the elevated minimal methionine requirement seen in all tumor types. In order to prevent immunological reactions which might be produced by multiple dosing of rMETase and to prolong the serum half-life of rMETase, the N-hydroxysuccinimidyl ester of methoxypolyethylene glycol propionic acid (M-SPA-PEG 5000) has been coupled to rMETase. Molar ratios of M-SPA-PEG-5000 (PEG) to rMETase from 10 to 40 were used for PEGylation of rMETase. PEGylation reactions were run at 20 degrees C for 30 to 60 min in reaction buffer (20 mM sodium phosphate buffer, pH 8.3). The PEGylated molecules (PEG-rMETase) were purified from unreacted PEG with Amicon 30 K centriprep concentrators or by Sephacryl S-300 HR gel-filtration chromatography. Unreacted rMETase was removed by DEAE Sepharose FF anion-exchange chromatography. The resulting PEG-rMETase subunit, from a PEG/rMETase ratio of 30/1 in the synthetic reaction, had a molecular mass of approximately 53 kda determined by matrix-assisted laser desorption/ionization mass spectrometry, indicating the conjugation of two PEG molecules per subunit of rMETase and eight per tetramer. PEG-rMETase molecules obtained from reacting ratios of PEG /rMETase of 30/1 had enzyme activities of 70% of unmodified rMETase. PEGylation of rMETase increased the serum half-life of the enzyme in rats to approximately 160 min compared to 80 min for unmodified rMETase. PEG-rMETase could deplete serum methionine levels to less than 0.1 microM for approximately 8 h compared to 2 h for rMETase in rats. Efficacy studies of PEG-rMETase on human lung cancer and kidney cancer cells in vitro demonstrated a 50% inhibitory concentration (IC50) of 0.04 and 0.06 units/ml, respectively. These IC50 values were almost identical to unmodified rMETase, thus indicating maintenance of antitumor efficacy in the PEGylated enzyme. PEG-rMETase had an IC50 for normal lung and kidney cells of 0.8 and 1.5 units/ml, respectively, similar to rMETase. The efficacy data indicated that PEG-rMETase maintained the high level tumor selectivity of rMETase. PEG-rMETase injected intravenously in mice demonstrated a tumor/blood retention ratio of approximately 1/6 compared to 1/10 of unmodified enzyme, indicating that PEG-rMETase distributes to the tumor at least as effectively as rMETase.

Antimetastatic activity of the new platinum analog [Pt(cis-dach) (DPPE).2NO3] in a metastatic model of human bladder cancer

Surgical orthotopic implantation (SOI) of histologically intact human RT-4 bladder tumor tissue in nude mice resulted in local growth, invasion, regional extension and metastases as well as distant metastases to other organ sites and lymph nodes, thus mimicking the bladder cancer patient. This metastatic bladder tumor animal model was treated with two doses of new platinum analog ¿Pt(cis-dach)(DPPE).2NO3¿ for the evaluation of antimetastatic efficacy compared to two doses of cisplatinum. Unlike the untreated control group or the group treated with the low dose of cisplatinum, there were no metastases in either the high or low-dose platinum-analog-treated groups and the high-dose cisplatinum-treated group. The results obtained with this patient-like nude-mouse model of bladder cancer indicate that the new platinum analog appears to be a valuable lead compound with antimetastatic efficacy and clinical potential.

The second finger of Urbs1 is required for iron-mediated repression of sid1 in Ustilago maydis

The urbs1 gene encodes a transcriptional regulator of siderophore biosynthesis in Ustilago maydis. Biological and DNA-binding activities of the two putative zinc-finger motifs of Urbs1 were studied by analyzing mutants containing altered finger domains. The mutated urbs1 alleles from three previously described N'-methyl-N'-nitro-N-nitrosoguanidine (NTG) mutants were mapped and cloned by a gap-repair procedure. Sequence analyses revealed single amino acid substitutions in two of the NTG mutants. Both mutations (G-507 to D in urbs1-1 and P-491 to L in urbs1-3), which are located in the Urbs1 C-terminal finger domain, reduced DNA-binding activity by 10-fold and were sufficient to confer a urbs1-minus phenotype. The third NTG urbs1 mutant (urbs1-2) also contained a mutation in one of the conserved amino acids (P-518 to S) in the C-terminal finger domain, but this mutation alone was not sufficient to confer a urbs1-minus phenotype. A second frame shift mutation was identified in urbs1-2 and is necessary for the urbs1-minus phenotype. In an analysis of the function of the N-terminal finger of Urbs1, the conserved amino acid Arg-350 was mutated to leucine. A Urbs1 protein with this mutation complemented a urbs1 null mutant strain. By contrast, a similar mutation in the C-terminal domain abolished the ability of Urbs1 to regulate siderophore biosynthesis and greatly reduced its ability to bind target DNA.

The distal GATA sequences of the sid1 promoter of Ustilago maydis mediate iron repression of siderophore production and interact directly with Urbs1, a GATA family transcription factor

The sid1 and urbs1 genes encode L-ornithine N5-oxygenase and a GATA family transcription regulator, respectively, for siderophore biosynthesis in Ustilago maydis. The basic promoter and iron-regulatory sequences of the U. maydis sid1 gene were defined by fusing restriction and Bal31 nuclease-generated deletion fragments of the promoter region with the Escherichia coli beta-glucuronidase (GUS) reporter gene. Sequences required for basal expression of sid1 mapped within 1043 bp upstream of the translation start site and include the first untranslated exon and first intron. Sequences needed for iron-regulated expression of sid1 were localized to a 306 bp region mapping 2.3 and 2.6 kb upstream of the ATG. The 306 bp region contains two G/TGATAA sequences, consensus DNA binding sites of GATA family transcription factors. Deletion or site-directed mutation of either or both GATA sequences resulted in deregulated expression of sid1. In vitro DNA binding studies showed that Urbs1 binds to the 3'-GATA site in the 306 bp iron-responsive region. However, deletion of 1.1 kb between the distal GATA sites and the basal promoter region led to deregulated expression of GUS, indicating that these GATA sequences are by themselves insufficient to regulate sid1. In vitro DNA binding and in vivo reporter gene analysis revealed that siderophores are not co-repressors of Urbs1.

Conversion of highly malignant colon cancer from an aggressive to a controlled disease by oral administration of a metalloproteinase inhibitor

In this study, we describe the activity of CT1746, an orally-active synthetic MMP inhibitor that has a greater specificity for gelatinase A, gelatinase B and stromelysin than for interstitial collagenase and matrilysin, in a nude mouse model that better mimics the clinical development of human colon cancer. The model is constructed by surgical orthotopic implantation (SOI) of histologically-intact tissue of the metastatic human colon tumor cell line Co-3. Animals were gavaged with CT1746 twice a day at 100 mg/kg for 5 days after the SOI of Co-3 for 43 days. In this model CT1746 significantly prolonged the median survival time of the tumor-bearing animals from 51 to 78 days. Significant efficacy of CT1746 was observed on primary tumor growth (32% reduction in mean tumor area at day 36), total spread and metastasis (6/20 treated animals had no detectable spread and metastasis at autopsy compared to 100% incidence of secondaries in control groups). Efficacy of CT1746 could also be seen on reducing tumor spread and metastasis to individual organ sites such as the abdominal wall, cecum and lymph nodes compared to vehicle and untreated controls. We conclude that chronic administration of a peptidomimetic MMP inhibitor via the oral route is feasible and results in inhibition of solid tumor growth, spread and metastasis with increase in survival in this model of human cancer, thus converting aggressive cancer to a more controlled indolent disease.

Reversible inhibition of IL-8 receptor B mRNA expression and proliferation in non-small cell lung cancer by antisense oligonucleotides

We examined the importance of IL-8 receptor B mRNA expression in the growth of non-small cell lung cancer (NSCLC). Using antisense oligonucleotide ICN 197, we were able to inhibit IL-8 R B mRNA expression in vitro. The sequence specific effect of antisense oligonucleotide and down-regulation of IL-8 R B mRNA was shown by Reverse Transcription Polymerase Chain Reaction (RT-PCR) and Southern blot analysis. The proliferation of treated cells was measured by 3H thymidine incorporation. We found that treatment of NSCLC cells caused reversible growth inhibition and reversible down regulation of IL-8 R B mRNA. Furthermore, we observed that the treatment of nude mice with oligonucleotide ICN 197 inhibited the growth of tumors developed from NSCLC cells injected subcutaneously. Our data in vitro suggest that IL-8 receptor B mRNA expression is required to maintain the proliferative rate of NSCLC. Based on the data in vivo. oligonucleotide ICN 197 may be considered for the development of novel therapeutic treatment for lung cancer.

Salt stress induces an increased expression of V-type H(+)-ATPase in mature sugar beet leaves

In the halotolerant sugar beet co-expression of V-ATPase and a vacuolar Na+/H(+)-antiporter provides a mechanism for vacuolar salt sequestration. To analyze salt-induced changes in the expression of the vacuolar H(+)-ATPase (V-ATPase) a partial cDNA of the proton-channel forming subunit c was cloned by RT-PCR. Southern blot analysis indicated a small gene family. In control plants transcript levels were high in roots and young growing leaves but low in fully expanded leaves. In mature leaves salt exposure (400 mM, 48 h) induced a strong increase in subunit c-mRNA. Transcripts for the catalytic subunit A followed a similar developmental and stress-modulated pattern, indicating a coordinate regulation of transcripts for both V-ATPase subunits. Concomittant with the mRNA increases the amount of V-ATPase protein increased as well.

New cosmid vectors for library construction, chromosome walking and restriction mapping in filamentous fungi

New cosmid vectors were constructed for the ascomycete fungus, Magnaporthe grisea and the basidiomycete fungus, Ustilago maydis. These vectors are capable of transforming M. grisea at frequencies of up to 5 transformants/micrograms linear DNA and U. maydis at up to 25 transformants/microgram circular DNA for integrative transformation. In addition, 2800 transformants/microgram DNA are possible when using an autonomously replicating vector. Since the promoters used in these vectors function in other ascomycete and basidiomycete fungi, we anticipate that these vectors will be widely applicable.

Interferon gamma is highly effective against orthotopically-implanted human pleural adenocarcinoma in nude mice

The efficacy of recombinant human gamma interferon (rh IFN-gamma) was evaluated for the treatment of human pleural adenocarcinoma in a patient-like nude mice model which is constructed by surgical orthotopic implantation (SOI) of histologically-intact human tumor tissue. The human non-small-cell lung cancer cell line H-460 was used for the study. Gamma interferon was tested in three different dosages (25,000 U, 50,000 U and 100,000 U) versus an untreated control through i.p. injection twice a day for five days, which was started 48 hours after SOI; The results showed that IFN-gamma can prolong the survival time of the tumor-bearing animals. The symptoms and signs of hypoxia such as restricted physical activity and cyanosis due to primary tumor growth in the thoracic cavity as well as cachexia developed much earlier in the control than in the IFN-gamma-treated mice. The mice in the control group had succumbed by day-23 after tumor implantation, however at that time 67% of the mice in the 100,000 U-treated group, 15% of the mice in the 50,000 U-treated group, and 16% of the mice in the 25,000 U-treated group were still alive. The orthotopically-transplanted tumor grew rapidly and metastasized to the lung and liver in the untreated control. In the IFN-gamma-treated groups both primary tumor growth and metastasis were reduced, probably accounting for the increased survival rate. The results demonstrated dose-dependent efficacy of IFN-gamma in suppressing symptomology, primary tumor growth, invasiveness and metastasis of the human lung cancer cell line H 460, and increased survival of the tumor-bearing animals. These results suggest clinical trials of IFN-gamma should begin for treatment of pleural adenocarcinoma for which there is no current effective therapy.

A clinical nude mouse metastatic model for highly malignant human pancreatic cancer

Pancreatic cancer is a highly aggressive and treatment-refractory cancer. A clinically-relevant animal model is necessary to develop therapy for metastatic pancreatic cancer. In this study we evaluated the efficacy of mitomycin C (MMC) and 5-FU against the human pancreatic adenocarcinoma cell line PAN-12 in an orthotopic human metastatic pancreatic cancer nude mice model. The model is constructed by surgical orthotopic implantation (SOI) of histologically intact tumor tissue in the tail portion of the pancreas near the spleen. PAN-12 grew very aggressively in the control group of nude mice with extensive local invasion and distant metastasis to various organs with a propensity for the lung but to other organs as well, including the liver, kidney and regional and distant lymph nodes. In a striking effect none of the mice in the MMC-treated group developed tumor. Although mice in the 5-FU treated group survived statistically significantly longer than those in the untreated control, the overall incidence of metastasis in these mice was equivalent to those in the control. However no liver or kidney metastases were found in the 5-FU treated animals perhaps accounting in part for their longer survival. This "clinical" nude mouse model of highly metastatic pancreatic cancer can now be used to discover new effective agents for this disease.