In vivo selection of tumorigenic subline from non-tumorigenic human gastric carcinoma cells: In relation to proliferative propertiesIn vivo and in nude mice

Human gastric carcinoma cells from one of three long-term cultured cell lines (HPE-GAC-T) were injected into peritoneal cavities of BALB/c mice. The surviving celss in vivo were collected 3 days later. Following brief cultivation in vitro, those cells were reinjected into mice by the same route. This procedure was repeated 3 times. The cultured cancer cells recovered from the mice on the 3rd passage, at a 92.5% recovery rate, showed xenotransplantability in BALB/C nu/nu mice by subcutaneous injection. This subline (GAC-T · M-2) can be maintained in vitro but not in vivo while maintaining heterotransplantability. Three original cancer cell lines did not show tumorigenicity in nude mice. Animal passages by the same protocol failed to select tumorigenic sublines from the other cell lines (HPE-GAC-2 and -3). Factors affecting tumorigenic capacity of cancer cells in nude mice were studied in vivo and in vitro by comparing the properties of GAC-T · M-2 and parental cancer cells (GAC-T · O). Treatment of the hosts by injection of anti-asialoGM₁ antibody or cyclophosphamide, adult thymectomy of BALB/c mice, and 400 rads whole body irradiation did not enhance the growth of either GAC-T · M-2 or -T · O cells. There was no detectable difference between in vitro growth properties of the original and variant cells at a rather high cell density. However, at a low cell density GAC-T · M-2 cells showed a higher cell growth rate and increased [³H] thymidine incorporation and possessed higher colony forming activity in the liquid medium than their parental cells. High dense expression of epidermal growth factor (EGF) receptors was evident equally in both GAC-T cells, however, GAC-T · M-2 cells were more sensitive to downregulation by EGF in culture. Tumor cells of HPE-GAC-2 and -3 lines expressed minimum amount of EGF receptors on their cell surfaces and were refractory to additional EGF in culture. The results indicate that growth factors and their receptors are responsible for tumorigenicity in nude mice.     

Deletion of integrated hepatitis B virus genome and cellular flanking sequences in hepatocellular carcinoma cells in BALB/c mice

We have previously reported the establishment of well-differentiated BALB/c mouse liver (ML) cell lines. Transfection of these cell lines with hepatitis B virus (HBV) DNA led to the expression of HBV-specific antigens and integration of HBV sequences in the cellular genome. Two cloned HBV-transfected ML cell lines, ML2(HBV) and ML-3(HBV), expressed viral antigens and were highly tumorigenic in nude mice. However, the tumorigenicity of the two cell lines was significantly reduced in BALB/c mice. Southern blot analyses showed that the integrated HBV sequences were retained in tumors growing in nude mice but deleted in tumors growing in BALB/c mice. Furthermore, the deletion of HBV DNA was accompanied by deletion of chromosomal sequences flanking the HBV integration sites. In ML-2(HBV) cells, a significant reduction in chromosomal number was also observed. These results suggest that the immune response of BALB/c mice selected against hepatocellular carcinoma (HCC) cells expressing viral antigens and led to the proliferation of cells with deleted HBV sequences and concomitant chromosome aberrations. By using this mechanism, HCC cells escape the immune surveillance and gain the advantage of cell growth.     

Tumorigenicity of virus-transformed cells in nude mice is correlated specifically with anchorage independent growth in vitro.

Clonal isolates of mouse 3T3 cells and primary rat embryo cells, recovered nonselectively after infection by simian virus 40 (SV40), have been tested for tumorigenicity in the immune-deficient nude mice in order to determine the cellular growth properties in vitro specifically correlated with neoplastic growth in vivo. In addition, mouse 3T3 cells transformed by murine sarcoma virus (MuSV, Kirsten strain), and revertants isolated from cells fully transformed by either SV40 or MuSV were also studied. Results suggest that the single cellular property consistently associated with tumorigenicity in nude mice is the acquisition by virus-transformed cells of the ability to proliferate in vitro in the absence of anchorage. Other cellular parameters of virus-induced transformation, such as lack of sensitivity to high cell density and the capacity to grow in low serum concentration, are dissociable from cellular tumorigeneicity. This conclusion is supported further by the demonstration that specific selection in vivo for tumorigenic cells from anchorage-dependent cells results in the isolation of anchorage-independent cells. Conversely, a single-step selection in vitro for anchorage-independent cells from nontumorigenic cells results in a simultaneous selection of highly tumorigenic subclones.     

Tumorigenicity of human T-cell leukemia virus type I-infected cell lines in severe combined immunodeficient mice and characterization of the cells proliferating in vivo

The mechanism involved in leukemogenesis and neoplastic cell growth of adult T-cell leukemia (ATL) still remains unclear. We examined the tumorigenicity of human T-cell leukemia virus type I (HTLV-I)-infected cell lines in an in vivo cell proliferation model using severe combined immunodeficient (SCID) mice. Eleven HTLV-I-infected cell lines were injected into SCID mice and we found that 4 of them were capable of proliferating in SCID mice. Three of four transplantable cell lines are derived from the leukemic cell clone and 6 of 6 HTLV-I-infected cell lines of nonleukemic cell origin could not engraft in SCID mice. Interestingly, it was shown that some HTLV-I-infected and interleukin-2 (IL-2)-dependent cell lines could successfully engraft in SCID mice. The expression of IL-2 mRNA was not detected in these cell lines growing either in vivo or in vitro. HTLV-I viral products were not detected in 3 of 4 transplantable cell lines proliferating in vivo. Peripheral blood T cells immortalized by introduction of tax gene of HTLV-I were found to have no tumorigenic potential in SCID mice. These data suggest that (1) HTLV-I-infected cell lines of nonleukemic cell origin do not have enough leukemogenic changes to acquire the tumorigenic potential in SCID mice; (2) the IL-2 autocrine mechanism is not directly involved in the tumor cell growth; (3) viral gene expression is not needed for the maintenance of neoplastic cell growth; and (4) the expression of tax gene is not sufficient for the neoplastic cell growth in vivo.     

重组反义c-myc 腺病毒对人胃癌细胞的体内及体外分子治疗

目的研究重组反义ｃｍｙｃ腺病毒对胃癌细胞的体内外生物学作用．方法采用ＬａｃＺ基因Ｘｇａｌ染色、ＭＴＴ,ＤＮＡ梯度降解试验、原位末端标记、流式细胞仪、ＰＣＲ分析、裸鼠致瘤性、裸鼠皮下移植瘤模型实验等方法,对反义ｃｍｙｃ重组腺病毒在人胃癌ＳＧＣ７９０１细胞系中的作用进行体内外研究．结果ＡｄＡＳｃｍｙｃ对ＳＧＣ７９０１细胞能产生明显的生长抑制作用,ＭＴＴ显示生长抑制率为４４１％．ＤＮＡ梯度降解试验、原位末端标记、流式细胞仪显示ＡｄＡＳｃｍｙｃ诱导了ＳＧＣ７９０１细胞凋亡．经ＡｄＡＳｃｍｙｃ处理的ＳＧＣ７９０１细胞裸鼠致瘤性消失．ＡｄＡＳｃｍｙｃ对裸鼠皮下移植瘤模型瘤内注射能有效降低肿瘤的生长速度,生长抑制率为６８９％．结论ＡｄＡＳｃｍｙｃ对胃癌细胞具有显著的体内外生长抑制及凋亡诱导作用     

白细胞介素—2基因转导入胃癌细胞的实验研究

为研究白细胞介素－２基因转导人胃癌细胞的可行性和有效性，用直人核表达载体，将人ＩＬ－２ｃＤＮＡ转导入人胃产吕细胞株ＳＧＣ－７９０１细胞表达，并观察了基因转导和表达对胃癌细胞体外生长特性和ＬＡＫ细胞的肿瘤杀伤作用的影响，以及基因转导细胞的体内致瘤性。     

白细胞介素-2基因转导人胃癌细胞的实验研究

为研究白细胞介素－２（ＩＬ－２）基因转导人胃癌细胞的可行性和有效性，用真核表达载体，将人ＩＬ－２ｃＤＮＡ转导入人胃癌细胞株ＳＧＣ－７９０１细胞表达，并观察了基因转导和表达对胃癌细胞体外生长特性和ＬＡＫ细胞的肿瘤杀伤作用的影响，以及基因转导细胞的体内致瘤性。结果表明，人ＩＬ－２ｃＤＮＡ可以转导入人胃癌细胞，并表达有活性的ＩＬ－２，基因转导不改变胃癌细胞的体外生长特性，并能增强ＬＡＫ细胞的肿瘤杀伤作用，降低或消除胃癌细胞的体内致瘤性。本研究结果提示：ＩＬ－２基因转导胃癌细胞可能是防治胃癌的有效方法。     

In vivo horizontal oncogenesis by a human tumor in nude mice.

A human mucinous cystadenocarcinoma of the ovary was propagated in nude mice. After cryopreservation of the 3rd-passage xenograft for 4 years, subsequent in vivo transplants showed the emergence of two distinct populations, one resembling the original human adenocarcinoma and the other resembling a spindle-cell sarcoma. These two tumor cell populations were confirmed to be human and murine, respectively, by cytogenetic study, and the epithelial tumor cells were further shown to be of human origin by immunoperoxidase staining of blood group A antigen. Separation of the two tumor cell populations in vitro permitted the independent propagation of the human and murine tumor cells in vitro and in vivo. The murine sarcoma was also capable of growth in ordinary BALB/c mice. These results indicate that human cancer cells can induce malignancy in adjacent, putatively normal, cells of nude mice in vivo.     

Effects of epidermal growth factor on the growth of human gastric cancer cell and the implanted tumor of nude mice

AIM：Epidermal growth factor(EGF)plays an important role in the regulation of gastrointestinal tissue growth and development,and it can stimulate epithelial proliferation,cell differentiation and growth,it has been established that the EGF can promote gastric cytoprotection and ulcer healing but the potential ability of EGF to reaulate the gastric cancer growth is unknown,This study is to investigate the influence of EGF on human gastric cancer cell and the implanted tumor growth of nude mice.METHODS:The cell growth rates of human gastric adenocarinome cell lines MKN-28,MKN-45,SGC-7901 and normal human gastric epithelial cells 3T3 were assessed when incubated with recombinant human EGF(rhEGF,0.05,0.1,0.5,1.0,10,50,100mg.L^-1)using MTT method ,The cells of MKN-28,MKN-45,SGC-7901(gastric cancer tissue 1.5mm^3)were implanted in the BALB/cA nude mice for 10 days,The EGF was given intraperitoneally(15,30,60μg.kg^-1)for 3 weeks.The body weights of the tumor bearing animals and their tumor mass were measured afterwards to assess the mitogenic effect of rhEGF in the nude mice.RESULTS:Within the concentration range of 0.05-100mg.L^-1 rhEGF could increase the cell growth of normal 3T3 cells (cell growth rate 100%vs 102.8%,P<0.05)but partially restrain the gastric cancer cell growth,The latter effect was related to cell differentiation ,In 15-60μg/kg rhEGF groups,the mean implanted tumor mass of MKN-28 cell were 1.75g,1.91g,2.08g/NS group 1.97g(P>0.05),the mean tumor mass of SGC-7901 cell were 1.53g,1.07g,1.20g/NS group 1.07g(P>0.05),and for MKN-45 cell,the tumor mass were respectively 1.92g,1.29g,1.77g/NS group 1.82g(P>0.05) So rhEGF had no obvious effect on implanted MKN-28,SGC-7901 and MKN-45 tumor growth.CONCLUSION:EGF has no stimulating effect on the human gastric cancer cell growth neither in vitro nor in vivo.     

Constitutive activation of the interleukin 2 gene in the induction of spontaneous in vitro transformation and tumorigenicity of T cells.

There is growing evidence to suggest that tumorigenic transformation of cells may result from aberrant regulation of autocrine growth factor production. In the current study we describe the spontaneous in vitro transformation of T-lymphocyte cell lines during routine cell culture as evidenced by autonomous growth without any requirement for stimulation or exogenous interleukin 2 (IL-2). These cells constitutively expressed the IL-2 gene and were inhibited from proliferating by addition of antibodies against IL-2, the IL-2 receptor, or IL-2 antisense oligonucleotides, thereby suggesting that the cell transformation resulted from IL-2-mediated autocrine growth. The transformed cells when injected into nude but not normal mice induced tumors that were inhibited by antibodies against IL-2 and the IL-2 receptor as well as by immunosuppressive drugs such as cyclosporin A. These studies demonstrate that aberrant regulation of IL-2 production can lead to spontaneous transformation of T cells in vitro, capable of inducing tumors in vivo. Our studies not only provide evidence for the important role played by autocrine growth factors in tumorigenicity but also stress the need to use caution while performing immunotherapy using in vitro-cultured T cells against cancer and viral infections, particularly in an immunodeficient host, to exclude any possible transfer of transformed mutant cells.     

Recombinant human interleukin-4 inhibits growth of some human lung tumor cell lines in vitro and in vivo

Cytokines play an important role in activating the immune system against malignant cells. One of these cytokines, interleukin-4 (IL-4) has entered clinical phase I trials because of its immunoregulatory potency. In the present study we report that recombinant human (rh) IL- 4 has major direct antiproliferative effects on one human lung cancer cell line (CCL 185) in vitro as measured by a human tumor cloning assay (HTCA), tritiated thymidine uptake, and counting cell numbers and marginal activity in a second cell line (HTB 56) in the HTCA. This activity could be abolished by neutralizing antibody against rhIL-4. The biological response of the tumor cells to the cytokine is correlated with expression of receptors for human IL-4 on both the mRNA level and the protein level. The responsive cell line, CCL 185, secretes IL-6 after being incubated with rhIL-4. On the other hand, neutralizing antibodies against IL-6 showed no influence on the growth modulatory efficacy of rhIL-4 in this cell line. Furthermore, CCL 185 does not show detectable production of IL-1, tumor necrosis factor alpha or interferon gamma after incubation with rhIL-4. Thus, the response to rhIL-4 is not mediated through autocrine production of these cytokines triggered by rhIL-4. In a next series of experiments some of the cell lines were xenotransplanted to BALB/c nu/nu mice. Subsequently, the mice were treated for 12 days with two doses of 0.5 mg/m2 rhIL-4 or control vehicle subcutaneously per day. Treatment with rhIL-4 yielded a significant inhibition of tumor growth versus control in two of the non-small cell lung cancer cell lines being responsive in vitro (CCL 185, HTB 56). Histology of the tumors in both groups showed no marked infiltration of the tumors with murine hematopoietic and lymphocytic cells consistent with the species specificity of IL-4. In contrast, no tumor growth inhibition was found in the small cell lung cancer cell lines (HTB 119, HTB 120) being nonresponsive in vitro. We conclude that rhIL-4 has direct antiproliferative effects on the growth of some human non-small cell lung cancer cell lines in vitro and in vivo, which together with its regulatory effects on various effector cell populations makes this cytokine an interesting candidate for further investigation in experimental cancer treatment.     

The therapeutic effects of recombinant adenovirus RA538 on human gastric carcinoma cells in vitro and in vivo

AIM:To evaluate the potential of RA-538 gene therapy for gastric carcinoma.METHODS:Human gastric carcinoma cell line SGC7901 treated with Ad-RA538 or Ad-LacZ were analysed by X-gal stain, MTT, DNA ladder, Tunel, flow cytometric analysis, PCR, and Western Blot in vitro. The tumorigenicity and experimental therapy in nude mice model were assessed in vivo.RESULTS:Ad-LacZ could efficiently transfer the LacZ gene into SGC7901 cells. X-gal-positive cells at MOI 25, 50, 100, and 200 were 90%, 100%, 100%, and 100% respectively. Ad-RA538 could strongly inhibit cell growth and induced apoptosis in SGC7901 cells.The proliferation of the Ad-RA538-infected SGC7901 cells was reduced by 76.3%.The mechanism of killing of gastric carcinoma cells by Ad-RA538 was found to be apoptosis by DNA ladder,Tunel and flow cytometric analysis.The tumorigenicity in nude mice using Ad-RA538 showed that all three mice failed to form tumor from 7 to 30 days compared with Ad-LacZ and parent SGC7901 cells. Experimental therapy on the nude mice model bearing subcutaneous tumor of SGC7901 cells showed that intratumor instillation of Ad-RA538 inhibited the growth of the tumors. Ad-RA538-treated tumors were inhibited by 60.66%, compared with that of the tumor injected with Ad-LacZ and mock.CONCLUSION: The expression of Ad RA538 can inhibit growth and induce apoptosis of gastric cancer cell in vitro and in vivo. Ad RA538 can be used potentially in gene therapy for gastric carcinoma.     

Cimetidine inhibits in vivo growth of human colon cancer and reverses histamine stimulated in vitro and in vivo growth.

The effect of histamine and cimetidine on the growth of four human colon cancer cell lines was studied. Histamine significantly stimulated the uptake of tritiated thymidine in vitro in a dose dependent manner, to a maximum of 120% and 116% of controls for C170 and LIM2412, respectively. This effect was antagonised by cimetidine, but not diphenhydramine. Histamine also stimulated a dose dependent increase in cyclic adenosine monophosphate accumulation in C170 cells, antagonised by cimetidine. When grown as subcutaneous xenografts in Balb/c nu/nu mice, cimetidine had a significant inhibitory effect on the same two cell lines. The final volume of C170 tumours in animals given cimetidine was 44% of controls. This response was dose dependent, plateauing at a cimetidine dose of 50 mg/kg/day. The final volume of LIM2412 tumours in animals given cimetidine was 60% of controls. Histamine administered locally by a mini-osmotic pump stimulated C170 tumour growth to 164% of controls, was antagonised by cimetidine at a dose of 200 mg/kg/day, but not by lower concentrations. Histamine has a trophic effect on at least two colorectal cancer cell lines in vivo and in vitro. As this effect is antagonised by cimetidine, it may be mediated via tumour histamine type 2 receptors.     

Ephrin A2 receptor targeting does not increase adenoviral pancreatic cancer transduction in vivo

AIM： To generate an adenoviral vector specifically targeting the EphA2 receptor （EphA2R） highly expressed on pancreatic cancer cells in vivo. METHODS： YSA, a small peptide ligand that binds the EphA2R with high affinity, was inserted into the HI loop of the adenovirus serotype 5 fiber knob. To further increase the specificity of this vector, binding sites for native adenoviral receptors, the coxsackie and adenovirus receptor （CAR） and integrin, were ablated from the viral capsid. The ablated retargeted adenoviral vector was produced on 293T cells. Specific targeting of this novel adenoviral vector to pancreatic cancer was investigated on established human pancreatic cancer cell lines. Upon demonstrating specific in vitro targeting, in vivo targeting to subcutaneous growing human pancreatic cancer was tested by intravenous and intraperitoneal administration of the ablated adenoviral vector. RESULTS： Ablation of native cellular binding sites reduced adenoviral transduction at least 100-fold. Insertion of the YSA peptide in the HI loop restored adenoviral transduction of EphA2R-expressing cells but not of cells lacking this receptor. YSA-mediated transduction was inhibited by addition of synthetic YSA peptide. The transduction specificity of the ablated retargeted vector towards human pancreatic cancer cells was enhanced almost 10-fold in vitro. In a subsequent in vivo study in a nude （nu/nu） mouse model however, no increased adenoviral targeting to subcutaneously growing human pancreas cancer nodules was seen upon injection into the tail vein, nor upon injection into the peritoneum. CONCLUSION： Targeting the EphA2 receptor increases specificity of adenoviral transduction of human pancreatic cancer cells in vitro but fails to enhance pancreatic cancer transduction in vivo.     

T24 human bladder carcinoma cells with activated Ha-ras protooncogene: nontumorigenic cells susceptible to malignant transformation with carcinogen.

A comparative analysis of T24 human bladder carcinoma cells and N-methyl-N'-nitro-N-nitrosoguanidine (MeNNG)-transformed derivatives (MeNNG-T24 cells) revealed the following: (i) The presence of an activated c-Ha-ras gene (in the absence of the normal allele) is insufficient to confer upon T24 cells a tumor-associated phenotype. (ii) MeNNG-transformed T24 cells not only acquire tumor-associated (in vitro) traits (growth in soft agar and rhodamine retention) but, are highly tumorigenic in nude mice. (iii) It is possible to render T24 cells tumorigenic by chemical transformation; therefore, the reason that T24 cells lack tumorigenicity is not because of possible incompatibilities between these cells and nude mice but, in fact, because T24 cells are not malignant. (iv) The loss of expression of a transformation-related Mr 67,000 phosphoprotein by MeNNG-T24 cells after explantation of these cells from nude mouse tumors to in vitro culture indicates that culture conditions can be responsible for rapid phenotypic conversion of human tumor cell lines.     

三氧化二砷对裸鼠结肠癌腹腔转移的抑制作用

目的　研究Ａｓ２Ｏ３ 对裸鼠结肠癌腹腔转移的影响及其作用机制。方法　ＢＡＬＢ／Ｃｎｕ／ｎｕ裸鼠腹腔内接种结肠癌Ｌｏｖｏ 细胞后,随机分为５ 组,分别腹腔内注射生理盐水、表阿霉素及不同剂量的Ａｓ２Ｏ３ ,观察各组的致瘤率、腹水生成及生存时间。结果　表阿霉素、低剂量Ａｓ２Ｏ３ 与对照组相比可明显抑制裸鼠腹水的生长,延长生存期（ Ｐ＜ ０．０１） ;中高剂量Ａｓ２Ｏ３ 除上述作用外还可通过诱导肿瘤细胞凋亡消除腹腔内肿瘤细胞,抑制腹水生成,并使裸鼠寿命明显延长。结论　Ａｓ２Ｏ３ 可诱导结肠癌细胞凋亡,抑制或消除裸鼠肿瘤性腹水的生成,不同程度地延长生存期。     

Molecular therapy with recombinant antisense c-myc adenovirus for human gastric carcinoma cells in vitro and in vivo

BACKGROUND AND AIMS: This study used a recombinant antisense c-myc adenovirus (Ad-ASc-myc) to evaluate how alterations of c-myc expression in the SGC7901 human gastric carcinoma cells could influence the proliferation, apoptosis and the growth of human gastric tumors in nude mice. METHODS: The human gastric carcinoma cell line, SGC7901, treated with Ad-ASc-myc or adenovirus recombinants carrying LacZ gene (Ad-LacZ) were analyzed by using X-gal stain, MTT, DNA ladder, TUNEL assay, flow cytometric analysis, polymerase chain reaction and western blot in vitro. The tumorigenicity and experimental therapy in nude mice models were assessed in vivo. RESULTS: The Ad-ASc-myc could strongly inhibit cell growth and induce apoptosis in SGC7901 cells. The proliferation of the Ad-ASc-myc-infected SGC7901 cells was reduced by 44.1%. The mechanism of killing gastric carcinoma cells by Ad-ASc-myc was found to be apoptosis, which was detected by the use of a DNA ladder, TUNEL and flow cytometric analysis. Infection of Ad-ASc-myc in nude mice showed that all three mice failed to form tumors from the 7 to 30 day period, compared with injection of Ad-LacZ and parent SGC7901 cells. Experimental therapy on the nude mice bearing subcutaneous tumors of SGC7901 cells showed that intratumor instillation of Ad-ASc-myc inhibited the growth of the tumors. Recombinant antisense c-myc adenovirus-treated tumors were inhibited by 68.9%, compared with tumors injected with Ad-LacZ and control (LacZ and phosphate-buffered saline). CONCLUSION: The expression of Ad-ASc-myc can inhibit growth and induce apoptosis of gastric cancer cells in vitro and in vivo and thus is a potential clinical utility in gene therapy for the treatment of gastric carcinoma.     

In vivo induction of neoplastic growth in nude mouse connective tissue adjacent to xenografted human tumors

Summary Induction of neoplastic growth of murine stroma cells within the human tumor xenograft was observed after serial passage of CEA and 2-microglobulin producing human colonic SLu tumor xenografts in nu/nu BALB/c mice. Mouse tumors within the human tumor xenografts wre identified using specific immunohistologic staining techniques for mouse histocompatibility marker or human CEA. These mixed tumors could be distinguished from normal human tumor xenografts by a different relationship between development of the tumor marker in the serum and tumor size. We were able to establish transformed murine cells from human xenografts, either induced by SC injection of 1×10⁶ tumor cells of the SLu cell line or by human SLu or mammary carcinoma tissue serially passaged in athymic animals. The established human and murine cell lines were characterized by cytogenetic methods. Transformed murine cells were then continuously passaged in tissue culture. The transformed mouse fibroblasts proved to possess tumorigenicity in nude mice. In the case of SLu-derived mouse tumor cells, tumors also developed in the immunocompetent BALB/c mice using 1×10⁶ to 5×10⁶ tumor cells for SC transplantation.     

WWOX gene restoration prevents lung cancer growth in vitro and in vivo

The WWOX (WW domain containing oxidoreductase) gene at the common fragile site, FRA16D, is altered in many types of cancer, including lung cancer. We have examined the tumor suppressor function of WWOX in preclinical lung cancer models. The WWOX gene was expressed in lung cancer cell lines through recombinant adenovirus (Ad) infection (Ad-WWOX), and through a drug [ponasterone A, (ponA)]-inducible system. After WWOX restoration in vitro, endogenous Wwox protein-negative cell lines (A549, H460, and H1299) underwent apoptosis through activation of the intrinsic apoptotic caspase cascade in A549 and H460 cells. Ectopic expression of Wwox caused dramatic suppression of tumorigenicity of A549, H460, and H1299 cells in nude mice after Ad-WWOX infection and after ponA induction of Wwox expression in H1299 lung cancer cells. Tumorigenicity and in vitro growth of U2020 (Wwox-positive) lung cancer cells was unaffected by Wwox overexpression. This study confirms that WWOX is a tumor suppressor gene and is highly effective in preventing growth of lung cancer xenografts, whether introduced through viral infection or by induction of a silent WWOX transgene.