The protection of CoronaVac against the infection of wild-type SARS-CoV-2(WH-09)or Omicron variant in nude-hACE2 mice

Background:Immunocompromised individuals have an increased risk of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection and severe outcomes,but we pay less attention to these people.Athymic nude mice are a murine strain with a spontaneous deficiency of the Foxn1 gene,which can result in thymic degeneration or its absence,leading to immunosuppression and a decrease in the number of T cells,and are widely used in preclinical evaluations of disease in immunocompromised populations.Methods:We investigated the protection of the coronavirus disease 2019(COVID-19)inactivated vaccine(CoronaVac)against the infection of wild-type SARS-CoV-2(WH-09)or Omicron variant utilizing a hybrid-type nude-hACE2 mouse model.Results:Compared with nude-hACE2/W mice,the viral load in the brain and lung tissue of nude-hACE2 mice(nude-hACE2/WV)infected with WH-09 after vaccination significantly decreased,and the histopathological changes were also reduced.The viral load in the brain and lung tissue of nude-hACE2 mice(nude-hACE2/OV)infected with the Omicron variant after vaccination was lower than that in nude-hACE2/O,but histopathological symptoms did not improve significantly.Conclusion:CoronaVac provides some protection against infection of both WH-09 and the Omicron variant in the nude-hACE2 mice.Our findings aimed to provide a reference for vaccination against SARS-CoV-2 in immunocompromised populations.

Tumor radioimmunoimaging of chimeric antibody in nude mice with hepatoma xenograft

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Systemic study on the safety of immuno-deficient nude mice treated by atmospheric plasma-activated water

Cold atmospheric-pressure plasma is a new technology, widely used in many fields of biomedicine,especially in cancer treatment. Cold plasma can selectively kill a variety of tumor cells, and its biological safety in clinical trials is also very important. In many cases, the patient’s immune level is relatively low, so we first studied the safety assessment of plasma treatment in an immunocompromised animal model. In this study, we examined the safety of immuno-deficient nude mice by oral lavage treatment of plasma-activated water, and studied the growth status, main organs and blood biochemical indexes. Acute toxicity test results showed that the maximum dose of plasma treatment for 15 min had no lethal effect and other acute toxicity. There were no significant changes in body weight and survival status of mice after 2 min and 4 min of plasma-activated water(PAW)treatment for 2 weeks. After treatment, the major organs, including heart, liver, spleen, lung and kidney, were not significantly changed in organ coefficient and tissue structure. Blood biochemical markers showed that blood neutrophils and mononuclear cells were slightly increased, and the others remained unchanged. Liver function, renal function, electrolytes, glucose metabolism and lipid metabolism were not affected by different doses of PAW treatment. The above results indicate that PAW treatment can be used to treat immuno-deficient nude mice without significant safety problems.

Antitumor Activities and Apoptosis-regulated Mechanisms of Fermented Barley Extract in the Transplantation Tumor Model of Human HT-29 Cells in Nude Mice

Objective A subcutaneous transplantation tumor model of human HT-29 cells was established in nude mice to study the anticarcinogenic activities and apoptosis-regulatory mechanistic effect of aqueous extract of fermented barley with Lactobacillus plantarum dy-1 （LFBE）. Methods HT-29 cells were transplanted via subcutaneous injection of 1 × 107cells into the right flank of each nude mouse. Then, nude mice were treated for 30 days with LFBE （high-dose 2 g·kg-1·d-1; low-dose 1 g·kg-1·d-1） and for 7 days with 5-fluorouracil （5-FU, 25 g·kg-1·d-1） by gavage and intraperitoneal injection, respectively. Results Tumor volume and weight decreased significantly in both groups of nude mice treated with LFBE. In addition, the cell apoptosis rate of the LFBE group was significantly higher than that of the control group and 5-FU groups as measured by the TUNEL assay. Moreover, the real-time fluorescent quantitative PCR and Western blot methods further confirmed these apoptosis-enhancing and growth-inhibiting effects. The involvement of LFBE in inducing apoptosis was confirmed by the expression of Bax, Bcl-2, caspase-3, and cyclin D1. Conclusion The results showed that LFBE could induce subcutaneous transplantation tumor apoptosis in nude mice and could be used as a natural nutrient supplement or chemopreventive agent in the treatment of human colon cancer.

RADIOIMMUNOLOCALIZATION OF XENOGRAFTED HUMAN GASTRIC ADENOCARCINOMA WITH ^(131)I-LABELED MONOCLONAL ANTIBODY RWS_(4) IN NUDE MICE

The monoclonal antibody (MAb) RWS4 specific to membrane-associated antigen of human gastric adenocarcinoma was purified by protein A-Sepharose 4B affinity chromatography and labeled with 131I by chloramine-T method. 131-RWS,, was injected (65 μCi/10μg/0.2 ml, intraperitoneally) into the stomach cancer-bearing nude mice (solid tumor about 1 cm in diameter), and its biodistribution was studied by SPECT and gamma-counter over a peroid of 7 days. A clear image of transplanted tumor was observed on the 4th day, and the image became more clear on the 6th day. After SPECT scanning, the animals were killed on the 3rd to 7th day separately and radioactivity was detected in various organs. The ratios of T/NT were calculated. The results were shown as follows: tumor/blood, was 3.41±0.29 on the 6th day and the tumor/other organs (liver, spleen, stomach, lung, heart, kidney and brain etc.) were>3. The specificity of the 131I-RWS4 was 7.74±0.65.

RESPONSE OF HUMAN RENAL CANCER TO UFT IN NUDE MICE

A primary human renal cell carcinoma was developed as a xenograft (NT-25) and maintained by serial transplantation in nude mice. The effect of UFT on this neogrowth was tested and evaluated as well its distribution in the animal tissues. The concentration of UFT was higher in tumor tissues than that in other tissues and in the animal experimentation UFT was found to be effective on human renal cell carcinoma.

ANTI-HUMAN LUNG GIANT CELL CANCER (PG) EFFECT OF HUMAN LAK CELLS IN VITRO AND IN NUDE MICE

Human LAK cells were prepared by culturing normal human peripheral blood mononuclear cells (PBMC) with or without rIL-2 and assayed for T cell surface markers as well as anti-tumor activity against PC in vitro and in nude mice. Although the percentages of T3, T4, and T8 positive cells in rIL-2-activated cells did not differ significantly from those of control cells in vitro, the former showed stronger cytotoxicity than control cells to PG tumor cells in vitro. In vivo, LAK cells completely inhibited the growth of PG tumor in nude mice, whereas PBMC control cells were to be of no effect. The anti-tumor effect of human LAK cells in nude mice may offer a useful model to study the role of human LAK cells against human tumor in vivo.

A STUDY OF THE BIOLOGICAL CHARACTERISTICS OF HUMAN HEPATOMA XENOGRAFTS IN NUDE MICE AFTER IRRADIATION

Cell growth kinetics and changes in AFP in nude mice with human hepatoma xenografts were evaluated using the flow cytometry method. After receiving 10 Gy of radiation, the mice showed a marked delay in tumor growth; approximately 1 Gy of radiation caused a tumor growth delay of one day. Irradiation altered various phases of the cell cycle. An acute and temporary block of G2 cells was characteristic; FCM measurements demonstrated that about 58% of cells were blocked in the G2 phase and this blocking effect lasted 90 hours after an irradiation of 10 Gy. This indicated that human hepatoma xenografts in nude mice were quite sensitive to irradiation. It was also noted that the AFP decreased for 96 hours after irradiation. Changes in G2 cells after irradiation may be closely related to changes in AFP.

EFFECTS OF PSEUDOFYPE RETROVIRUS CONTAINING HUMAN N-RAS ANTISENSE GENE ON THE GROWTH OF HUMAN LIVER CANCER LTNM4 TRANSPLANTED IN NUDE MICE

An amphotropic pseudotype retrovirus containing human N-ras antisense gene was constructed and packaged with helper cells. It has been previously demonstrated that the virus did inhibit the growth of human hepatocarcinoma cell line PLC PRF/5 in vitro accompanied with the blockage of p21 expression. Based on these results, further study was carried on to examine the effect of these viruses on the growth of human hepatoma transplanted LTNM4 in nude mice. It has been shown that the retrovirus containing human antisense N-ras gene could inhibit the hepatoma in nude mice at a rate of 78% (P<0.05) as compared with saline control. No inhibition was observed in group treated with retrovirus which contained no N-ras sequence. These results in vivo lend further support that human N-ras antisense gene mediated by retrovirus could block the expression of the relevant oncogene and lead to the inhibition of cancer growth. It also provided the basis for further approaches of gene therapy for human cancer.

MORPHOLOGICAL SURVEY ON ENDOGENOUS C-TYPE VIRUSES INFECTING A HUMAN LUNG SQUAMOUS CARCINOMA PASSAGED IN NUDE MICE

A human lung squamous carcinoma was transplanted and passaged in Swiss-DF nude mice, called LSX-83, for more than five years in our laboratory. The morphological characteristics of the original tumor were maintained in passages from 4 to 33. But from the 35th generation, an increasing amount of tonofilaments and nuclear segregation with typical features was found with electron microscopy. The C-type virus particles were first detected in extra cellular space after 40 passages. The viruses were observed in different stages of growth, but their distribution and number did not show apparent change up to 54 passages. Such findings suggest that LSX-83 cells probably possess certain barrier of resistance against C-type viruses. The relation between C-type viruses and the morphological changes of LSX-83 cells was discussed.

Metastatic human hepatocellular carcinoma models in nude mice and cell line with metastatic potential

Metastatic human HCC model is needed for the studies on mechanism and intervention of metastatic recurrence. By using orthotopic implantation of histologically intact tissues of 30 surgical specimens, a patient like metastatic model of human HCC in nude mice (LCI-D20)and a Iow metastatic model of human HCC in nude mice LCI-D35 ) have been established. All mice with transplanted LCI-D20 tumors exhibited extremely high metastatic ability including spontaneous metastasis to liver, lungs, lymph nodes and peritoneal seeding.Remarkable difference was also found in expression of some of the invasiveness related genes and growth factors between the LCI-D20 and LCI-D35 tumors. PAI-Iincreased gradually following tumor progression in LCID20 model, and correlated with tumor size and AFP level,Phasic expression of tissue intercellular adhesion molecule-I in this model was also observed. Using corneal micropocket model, it was demonstrated that the vascular response induced by LCI-D20 tumor was stronger than that induced by LCI-D35 tumor. Similar report on metastatic human HCC model in nude mice and human HCC cell line with metastatic potential was rarely found in the literature. This LCI-D20 model has been widely used for the studies on intervention of metastasis, including antiangiogenesis, antisense approach, metalloproteinase inhibitor, differentiation inducer, etc. It is concluded that the establishment of metastatic human HCC model in nude mice and human HCC cell line with metastatic potential will provide important models for the in vivo and in vitro study of HCC invasiveness, angiogenesis as well as intervention of HCC recurrence.

Growth-inhibiting effects of taxol on human liver cancer in vitro and in nude mice

AIM To investigate the effects of taxol onSMMC-7721 human hepatoma and itsmechanisms.METHODS In vitro cell growth was assessedby trypan blue exclusion method.Experimentalhepatoma model was established by seedingSMMC-7721 cells subcutaneously into Balb/c(nu/nu)nude mice.In vivo tumor growth wasdetermined by measurement of tumor diameterwith Vernier calipers.The syntheses of DNA,RNA and protein were analyzed by incorporationof ~3H-thymidine,~3H-uridine and ~3H-leucinerespectively.Using light and electronmicroscopes to observe the morphologicalchanges of cells including mitosis andapoptosis.RESULTS Taxol was effective against SMMC-7721 human hepatoma cell growth in the rangesof 2.5 nmol/L-10 nmol/L with mitotic arrestand apoptosis in vitro.DNA,RNA and proteinsyntheses in cells were also obviouslysuppressed by in vitro treatment of taxol for72 h.Taxol at 2.5 nmol/L reduced ~3H-thymidineuptake to about 34% of the control value(P【0.05).Increasing the dose of taxol to20 nmol/L resulted in a greater decrease in ~3H-thymidine incorporation to 60% of the controlvalue(P【0.01).At a concentration of 20 nmol/L,the ~3H-uridine and ~3H-leucine uptakeswere reduced to 52%(P【0.05)and 63%(P【0.01),respectively.In vivo,taxolsignificantly inhibited SMMC-7721 tumor growthat 10 mg/kg,i.p.,once daily for 10 d.A morethan 90% decrease in tumor volume wasobserved by day 11(P【0.01)similarly withmitotic arrest and cell apoptosis.CONCLUSION Taxol has a marked anticanceractivity in SMMC-7721 human hepatoma both invitro and in nude mice.Its mechanisms might beassociated with mitotic arrest,subsequently,apoptosis of the hepatoma cells.No obvioustoxicity was observed with in vivoadministration of taxoi.

^(99m)Tc-labeled HAb18 McAb Fab fragment for radioimmunoimaging in nude mice bearing human hepatocellular carcinoma

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Effects of targeting magnetic drug nanoparticles on human cholangiocarcinoma xenografts in nude mice

BACKGROUND: Targeting is a new therapeutic tool for malignant tumor as a result of combining nanotechnology with chemotherapeutics. The aim of our study was to investigate the effects of magnetic nanoparticles enveloping a chemotherapeutic drug on human cholangiocarcinoma xenografts in nude mice. METHODS: The human cholangiocarcinoma xenograft model was established in nude mice with the QBC939 cell line. The nude mice were randomly assigned to 7 groups. 0.9% saline or magnetic nanoparticles, including high (group 2), medium (group 4) and low (group 5) dosages, were given to nude mice through the tail vein 20 days after the QBC939 cell line was implanted. Calculations were made 35 days after treatment in order to compare the volumes, inhibition ratios and growth curves of the tumors in each group. Mice in each group were sacrificed randomly to collect tumor tissues and other organs for electron microscopy and pathological examination. RESULTS: The high and medium dosage groups were significantly different from the control group (P<0.05). The tumor inhibition ratios for the high, medium and low dosage groups were 39.6%, 14.6% and 7.9%, respectively. The tumor growth curve of groups 5, 4, and 2 changed slowly in turn. The high and medium groups showed cell apoptosis under an electron microscope. CONCLUSION: Magnetic nanoparticles can inhibit the growth of human cholangiocarcinoma xenografts in nude mice.

Antitumor effects of artesunate on human breast carcinoma MCF-7 cells and IGF-IR expression in nude mice xenografts

Purpose： The objective of this study was to investigate the anti-tumor effects and analyze the mechanism of artesunate （ART） action on breast cancer in vivo using tumor transplanted nude mice. Methods： The human breast tumor cell line MCF-7 was transplanted into nude mice, and the animals were treated with various doses of ART alone or in combination with cyclophosphamide （CTX） or normal saline （NS）. The tumor inhibitory effects were observed and compared, and the ultrastructural morphology of the transplanted tumor cells was observed by electron microscopy. The apoptosis rates and cell cycle status were detected by flow cytometry （FCM）. The expression of apoptosis-related proteins p53, Bcl-2, Bax and Caspase-3 were detected by immunohistochemistry and IGF-IR was detected by western blot. The expression correlation for these proteins was also analyzed. Results： The tumor inhibition rates in the low dose ART group, high dose ART group, CTX group and combined drug therapy group were （24.39±10.20）%, （40.24±7.02）%, （57.01±5.84）% and （68.29±5.1）%, respectively. The cell cycle was arrested in phase G0/Gt after treatment with ART. The expression of Bcl-2 was significantly reduced, and the expression levels of Bax and Caspase-3 were significantly increased in the ART group compared to the negative control saline group. There was no significant difference detected in p53 expression. The Bcl-2 level was negatively related to Bax and Caspase-3. The western blotting results showed IGF-IR downregulation. Conclusions： ART inhibits the growth of MCF-7 breast tumor cell xenografts in nude mice. The anti-tumor mechanism of ART for human breast carcinoma in nude mice might be correlated with the alteration of apoptosis related protein expression, which may further induce apoptosis and inhibit cell proliferation.

Antitumor Activities and Apoptosis-regulated Mechanisms of Fermented Wheat Germ Extract in the Transplantation Tumor Model of Human HT-29 Cells in Nude Mice

Objective A subcutaneous transplantation tumor model of human HT-29 cells in nude mice was established to evaluate anticarcinogenic activities, and the apoptosis-regulated mechanism effect of aqueous extract of fermented wheat germ with Lactobacillus plantarum dy-1 （LFWGE）. Methods The HT-29 cells were transplanted via subcutaneous injection of 1×10^7cells into the right flank of each nude mouse. Then, nude mice were treated for 30 d with LFWGE （high-dose 2 g/kg/d; low-dose 1 g/kg/d） and for 7 d with 5-fluorouracil （5-FU, 25 mg/kg/d） by gavage and intraperitoneal injection, respectively. An inhibition of tumor growth was observed. Results Tumor volume and weights decreased significantly in both groups of nude mice treated with LFWGE. In addition, the cell apoptosis rate of the LFWGE group （2 g/kg/d, 60.2%＋4.4%; 1 g/kg/d, 58.6%＋6.9%） was significantly higher than that of the control group （11.5%＋1.6%） and 5-FU group （32.1%＋3.5%） as measured by the TUNEL assay. Moreover, the real-time fluorescent quantitative PCR and Western blot method further confirmed these enhancing apoptosis and growth inhibition effects. The involvement of LFWGE in inducing apoptosis was confirmed by the expression of Bax, Bcl-2, Caspase-3, and CyclinD1. Conclusion The results showed that LFWGE could induce subcutaneous transplantation tumor apoptosis in nude mice and could be as a natural nutrient supplements or chemopreventive agent in the treatment of human colon cancer.

Functional Mechanism of Resveratrol in Inhabiting Growth of Cells ls174t and Its Mechanism in Subcutaneously Transplanted Tumor of Nude Mice

To explore the functional mechanism of Resveratrol against colon cancer cells ls174t and the growth of colon cancer tissue of tumor-bearing mice, MTT method was used to observe the functions of resveratrol for inhibition against cells ls174t in vitro. Transmission electron microscope was used to observe the cell apoptosis. FCM assay was performed to measure the change of the cell apoptosis rate and of cell cycle. RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA. Western blot method was used to detect the expressions of bcl-2 and bax protein. Ceils ls174t were transplanted subcutaneously to nude mice to observe the effect of resveratrol on the growth of subcutaneously transplanted tumor, RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA in the tumor tissue. Western blot method was used to detect the expressions of bcl-2 and bax protein in the tumor tissue. Resveratrol has an effect of inhibiting proliferation of cells ls174t in vitro（P〈0.01）. It is able to induce the apoptosis of cells ls174t, causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol could inhibit the growth of subcutaneously transplanted tumor of nude mice（P〈0.05）, causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol can inhibit the growth of cells 174t and the growth of subcutaneously transplanted tumor. The mechanism is possibly related to the induction of the cell apoptosis and the regulation of bcl-2/bax expression.

Study of primary leiomyosarcoma induced by MNNG in BALB/C nude mice

INTRODUCTIONIt has been well known that MNNG is one of thestrong and multipotential carcinogens that havebeen frequently reported inducing malignant peptictumors.We have successfully induced rat and doggastric adenocarcinomas,squamous cell carcinomasof rat forestomach and gastric leiomyosarcoma

Orthotopical transplantation of human renal carcinoma tissue into nude mice and the establishment of a high metastatic cell line MRCC

Objective To establish a SOI model of human renal carcinoma and a high metastatic cell subline. Methods A human renal cell line RCC-9863 has been established by inoculating a human renal tumor tissue into nude mice s. c.. When RCC-9863 passaged for 20 times, the tissue from the same xemotransplant tumor were used to construct SOI model. Cultured the metastatic tissue in vitro, the tumor cell suspension was then injected orthotopically, The metastatic tissue obtained underwent the same procedure again. At last, the metastatic tumor was cultured in vitro and cloned. Results 15 days later, a tumor mass sized 1. 7 cm × 0. 6 cm in the nude mouse’s renal parenchyma was grown which lobulated, rude, and with multiply blood vessels and 55 days later later the mouse became moribund and metastases in the lungs were formed. The transplanted renal tumor in the SOI model grew fast and invasively and metastasized to lungs, lymphatic node and liver. A subline, MRCC, with metastatic ability to the lung was selected.