Specific Antitumor Effect Research Articles

Chimeric antigen receptor containing ICOS signaling domain mediates specific and efficient antitumor effect of T cells against EGFRvIII expressing glioma

BackgroundAdoptive transfer of chimeric antigen receptor (CAR)-modified T cells appears to be a promising immunotherapeutic strategy. CAR combines the specificity of antibody and cytotoxicity of cytotoxic T lymphocytes, enhancing T cells’ ability to specifically target antigens and to effectively kill cancer cells. Recent efforts have been made to integrate the costimulatory signals in the CAR to improve the antitumor efficacy. Epidermal growth factor receptor variant III (EGFRvIII) is an attractive therapeutic target as it frequently expresses in glioma and many other types of cancers. Our current study aimed to investigate the specific and efficient antitumor effect of T cells modified with CAR containing inducible costimulator (ICOS) signaling domain.MethodsA second generation of EGFRvIII/CAR was generated and it contained the EGFRvIII single chain variable fragment, ICOS signaling domain and CD3ζ chain. Lentiviral EGFRvIII/CAR was prepared and human CD3+ T cells were infected by lentivirus encoding EGFRvIII/CAR. The expression of EGFRvIII/CAR on CD3+ T cells was confirmed by flow cytometry and Western blot. The functions of EGFRvIII/CAR+ T cells were evaluated using in vitro and in vivo methods including cytotoxicity assay, cytokine release assay and xenograft tumor mouse model.ResultsChimeric EGFRvIIIscFv-ICOS-CD3ζ (EGFRvIII/CAR) was constructed and lentiviral EGFRvIII/CAR were made to titer of 106 TU/ml. The transduction efficiency of lentiviral EGFRvIII/CAR on T cells reached around 70% and expression of EGFRvIII/CAR protein was verified by immunoblotting as a band of about 57 kDa. Four hour 51Cr release assays demonstrated specific and efficient cytotoxicity of EGFRvIII/CAR+ T cells against EGFRvIII expressing U87 cells. A robust increase in the IFN-γ secretion was detected in the co-culture supernatant of the EGFRvIII/CAR+ T cells and the EGFRvIII expressing U87 cells. Intravenous and intratumor injection of EGFRvIII/CAR+ T cells inhibited the in vivo growth of the EGFRvIII expressing glioma cells.ConclusionsOur study demonstrates that the EGFRvIII/CAR-modified T cells can destroy glioma cells efficiently in an EGFRvIII specific manner and release IFN-γ in an antigen dependent manner. The specific recognition and effective killing activity of the EGFRvIII-directed T cells with ICOS signaling domain lays a foundation for us to employ such approach in future cancer treatment.

Oncolytic virotherapy for malignant glioma: translating laboratory insights into clinical practice

Glioblastoma multiforme, one of the most common and aggressive brain tumors in adults, is highly resistant to currently available therapies and often recurs. Due to its poor prognosis and difficult management, there is an urgent need for the development and translation of new anti-glioma therapeutic approaches into the clinic. In this context, oncolytic virotherapy arises as an exciting treatment option for glioma patients. These natural or genetically engineered viruses are able to effectively infect cancer cells, inducing a specific anti-tumor cytotoxic effect. In addition, some viruses have been redesigned to modulate glioma microenvironment, to express cytokines to boost a systemic anti-glioma immune response and to incorporate angiostatic genes to decrease glioma vasculature. Although recent clinical trials have confirmed the safety of oncolytic virotherapies in the brain, their moderate clinical efficacy has not yet matched the encouraging preclinical laboratory results. In this review, we will discuss the leading anti-glioma virotherapy approaches that are presently under preclinical and clinical evaluation. We will also review different delivery methods, in vivo virus behavior, fate, replication, intratumoral spread, activation of anti-tumor immune response, and targeting of glioma stem cells. We will focus on the advantages and limitations of each therapeutic approach and how to overcome these hurdles to effectively translate exciting laboratory results into promising clinical trials.

Potent and specific antitumor effect for colorectal cancer by CEA and Rb double regulated oncolytic adenovirus harboring ST13 gene.

Cancer Targeting Gene-Viro-Therapy (CTGVT) is constructed by inserting an antitumor gene into an oncolytic virus (OV). It is actually an OV-gene therapy, which has much better antitumor effect than either gene therapy alone or virotherapy alone in our previously published papers. This study is a modification of CTGVT by inserting a colorectal cancer (CRC) specific suppressor gene, ST13, into a CRC specific oncolytic virus, the Ad·CEA·E1A(Δ24), to construct the Ad·(ST13)·CEA·E1A(Δ24) for increasing the targeting tropism to colorectal cancer and it was briefly named as CTGVT-CRC. Although many studies on CEA promoter and ST13 gene were reported but no construct has been performed to combine both of them as a new strategy for colorectal cancer (CRC) specific therapy. In addition to the CRC specificity, the antitumor effect of Ad·(ST13)·CEA·E1A(Δ24) was also excellent and got nearly complete inhibition (not eradication) of CRC xenograft since ST13 was an effective antitumor gene with less toxicity, and a Chinese patent (No. 201110319434.4) was available for this study. Ad·(ST13)·CEA·E1A(Δ24) caused cell apoptosis through P38 MAPK (i.e. P38) which upregulated CHOP and ATF2 expression. The mitochondrial medicated apoptosis pathway was activated by the increase of caspase 9 and caspase 3 expression.

The killing effect of NY-ESO-1-sensitzed dendritic cells-induced cellular toxic lymphocyte on human retinoblastoma cell

Background Cell immunologic therapy for retinoblastoma （RB）is becoming a hot research topic. Cancer-testis antigen is a human immunogenic protein and is used to treat some tumors. However,its effect on RB has not been investigated. Objective The present study was to discuss the antigen specific anti-tumor effect of cytotoxic T lymphocytes （CTL）induced by the cancer-testis antigen, NY-ESO-l-sensitized dendritic cells （DCs）, on human RB. Methods PCR was performed to amplify target gene fragments from the NY-ESO-1 plasmids,and then the target gene fragments were digested with the restriction enzymes SalI and EcoRI. Harvested fragments were inserted into the pDC316 plasmid to construct the recombinant plasmid pDC316/NY-ESO-1. The expression of NY-ESO-1 protein in human RB cells strain, HXO-RB44,was detected by immunofluoreseence and Western blot. Monoeytes wereisolated from 60 ml of peripheral blood from a healthy donor using Ficoll density-gradient centrifugation with a cell density of 1 x 107/ml. DCs isolated from blood were stimulated with recombinant human granulocyte-macrophage colony stimulating factor （rhGM-CSF） and recombinant human interleukin-4 （ rhIL-4 ）. The recombinant plasmid pDC316/NY-ESO-1 was transfected into DCs and the DCs were co-cultured with T lymphocytes. The resultant CTL were used as effector ceils. The growth of the CTL was detected by MTT assay. The CTL were then added into the growth medium used for culturing HXO-RB44 cells and the vitality of the HXO-RB44 cells was assayed by MTT assay. Results The sequence of the cloned DNA fragment of the recombinant plasmid pDC316/NY-ESO-lwas conforms with the sequence of the NY-ESO-1 gene. The expression of the NY-ESO-1 protein in HXO-RB44 cells was tested by immunofluorescence and Western blot. DCs were successfully induced with rhIL-4 and rhGM-CSF from PBMC. The recombinant expression plasmid pDC316/NY-ESO-1 was successfully transferred into DCs. These DCs had high expression of surface molecules such as HLA-DR （42. 1% ） , CD80 （54.2%） , CD83 （39.7%） and CD86 （94.8%）. The CTL that was induced by DCs-sensitized with NY-ESO-1 specifically killed HXO-RB44 cells. CTL induced by the sensitized DCs had a stronger cytotoxic effect against HXO-RB44 cells compared with un-sensitized DCs and CTL un-induced with DCs, as shown by MTT asssay（ P〈0.05 ）. The anti-tumor activity was highest when the ratio of effector to target was 75 ： 1 （ P〈0. 05 ）. Conclusions DCs transfected by the recombinant plasmid pDC316/ NY-ESO-1 can induce the proliferation of allogenic CTLs, which showed a specific anti-tunmr effect against HXORB44 cells. These results present a new type of immunotherapy for the treatment of RB. Key words: Retinoblastoma; Ddendritic cell; Cytotoxic T lymphocyte; NY-ESO-1

Prostate Cancer-Specific and Potent Antitumor Effect of a DD3-Controlled Oncolytic Virus Harboring the PTEN Gene

Prostate cancer is a major health problem for men in Western societies. Here we report a Prostate Cancer-Specific Targeting Gene-Viro-Therapy (CTGVT-PCa), in which PTEN was inserted into a DD3-controlled oncolytic viral vector (OV) to form Ad.DD3.E1A.E1B(Δ55)-(PTEN) or, briefly, Ad.DD3.D55-PTEN. The woodchuck post-transcriptional element (WPRE) was also introduced at the downstream of the E1A coding sequence, resulting in much higher expression of the E1A gene. DD3 is one of the most prostate cancer-specific genes and has been used as a clinical bio-diagnostic marker. PTEN is frequently inactivated in primary prostate cancers, which is crucial for prostate cancer progression. Therefore, the Ad.DD3.D55-PTEN has prostate cancer specific and potent antitumor effect. The tumor growth rate was almost completely inhibited with the final tumor volume after Ad.DD3.D55-PTEN treatment less than the initial volume at the beginning of Ad.DD3.D55-PTEN treatment, which shows the powerful antitumor effect of Ad.DD3.D55-PTEN on prostate cancer tumor growth. The CTGVT-PCa construct reported here killed all of the prostate cancer cell lines tested, such as DU145, 22RV1 and CL1, but had a reduced or no killing effect on all the non-prostate cancer cell lines tested. The mechanism of action of Ad.DD3.D55-PTEN was due to the induction of apoptosis, as detected by TUNEL assays and flow cytometry. The apoptosis was mediated by mitochondria-dependent and -independent pathways, as determined by caspase assays and mitochondrial membrane potential.

Tumor Growth Inhibition by Olaparib in BRCA2 Germline-Mutated Patient-Derived Ovarian Cancer Tissue Xenografts

Most patients with ovarian carcinomas succumb to their disease and there is a critical need for improved therapeutic approaches. Carcinomas arising in BRCA mutation carriers display defective DNA double-strand break repair that can be therapeutically exploited by inhibition of PARP-1, a key enzyme in the repair of DNA single-strand breaks, creating synthetic lethality in tumor cells. To investigate synthetic lethality in vivo, we established a BRCA2 germline-mutated xenograft model that was developed directly from human ovarian cancer tissue, treated with the PARP inhibitor olaparib (AZD2281) alone and in combination with carboplatin. We show that olaparib alone and in combination with carboplatin greatly inhibit growth in BRCA2-mutated ovarian serous carcinoma. This effect was not observed in a serous carcinoma with normal BRCA function, showing a specific antitumor effect of olaparib in mutation carriers. Immunohistochemistry (cleaved caspase-3 and Ki-67 stains) of remnant tissue after olaparib treatment revealed significantly decreased proliferation and increased apoptotic indices in these tumors compared with untreated controls. Furthermore, olaparib-treated tumors showed highly reduced PARP-1 activity that correlated with olaparib levels. We established a BRCA2-mutated human ovarian cancer xenograft model suitable for experimental drug testing. The demonstrated in vivo efficacy of olaparib extends on the preclinical rationale for further clinical trials targeting ovarian cancer patients with BRCA mutations.

In vitro anti-tumor immune mechanism of nasopharyngeal carcinoma bispecific anti-idiotype antibody.

To compare the in vitro antitumor immune responses induced by bivalent bispecific anti-idiotype antibody G22-I50 and monovalent anti-idiotype antibody G22 and I50, and explore its possible mechanism. Proteins G22-I50, G22, and I50 were induced and identified by Western blot and ELISA. Peripheral blood monoclear cells (PBMC) were isolated and stimulated with G22-I50, G22, and I50 anti-idiotype antibodies, respectively. MTT assay and LDH release test were employed to examine the proliferation and cytotoxicity of the PBMC. The levels of IFN-gamma, IL-2, and IL-4 in the supernatant were detected by ELISA and changes of T lymphocyte subsets were determined by flow cytometry. Western blot showed that G22-I50, G22, and I50 had specific binding capabilities to FC2 (Ab1). The activities of G22-I50, G22, and I50 had recovered and these proteins could be used in the in vitro study. The proliferation and cytotoxicity of the PBMC stimulated with G22-I50 were significantly higher than those stimulated with G22 or I50. The level of IFN-gamma and IL-2 in the culture supernatant of the PBMC stimulated with G22-I50 was higher than that in the G22 or I50 group, but the level of IL-4 did not increase. Compared with the G22 or I50 group, the proportion of CD4(+) and CD8(+) T cells and CD4(+)/CD8(+) ratio significantly increased, and the proportion of CD4(+)CD25(+) T cells significantly decreased in the PBMC stimulated with G22-I50. G22-I50 has more potent immunogenicity and would enhance specific antitumor effect which might relate to improving PBMC proliferation, inducing the secretion of Th1 type cytokines, activating CD8(+)T cells, and suppressing the expression of CD4(+)CD25(+) T cells.

Combined biological treatment and chemotherapy for patients with inoperable cholangiocarcinoma.

TPS217 Background: Cholangiocarcinoma (CC) is a relatively rare cancer with a severe prognosis. There are no standard chemotherapy to offer incurable patients, but regimes combining cisplatin and gemcitabine are commonly used based on preliminary phase III data. In Denmark, a combination of gemcitabine, oxaliplatin and capecitabine has been evaluated in phase I and phase II trials. Based on experience with other gastrointestinal tumors, there seems to be an additional effect when combining chemotherapy and epithelial growth factor receptor (EGFR) antibodies. Effect of EGFR inhibitors is only seen if the down-stream signalling protein KRAS is not mutated. 50% of CC are expected to hold KRAS mutations. The purpose of the trial is to evaluate the specific anti-tumor effect of (i) chemotherapy and panitumumab in CC without KRAS mutations and (ii) chemotherapy alone in patients with KRAS mutations. Methods: Eligibility criteria are made to reflect daily clinical practice and diminish selection bias by allowing inclusion of patients with performance status 2, age up to 80 years, and evaluable (not necessarily measurable) disease. Furthermore, histopathology only needs to be consistent with adenocarcinoma arisen from bile ducts together with a radiologic diagnosis of CC. The study is designed as two parallel phase II trials selected by KRAS status. In each trial a two-stage design is chosen with inclusion of 15-18 patients in stage one and 25-33 patients in stage II. All patients receive gemcitabine 1000 mg/m2 and oxaliplatin 60 mg/m2 on day one plus capecitabine 1000 mg/m2 b.i.d. day one to seven on a two weeks cycle. If KRAS wild-type panitumumab 6 mg/kg is given day one. The primary endpoint is progression free survival and secondary endpoints response rate, toxicity, and overall survival. During the trial tumor tissue and regular blood tests are collected for future translational research. Accrual began in September 2008 and is considerably higher in the panitumumab group, where the last patient is expected to be included in mid-2010. Surprisingly, only 5-10% have KRAS mutation and this part of the study will continue longer. Results will be reported separately. No significant financial relationships to disclose.

A study on the specific immunological effect induced by DCs loaded with autospecific lung cancer antigen

Objective To discuss the specific immunological effect induced by DCs loaded with autospecific lung cancer antigen. Methods Primary lung cancer cells were cultured in vitro and prepared to antigen through thaw and freeze. Antigen was presented to tumor infiltrating lymphocyte(TIL) and T lymphocyte derived from peripheral blood by dendritic cells(DCs). The specific anti-tumor immunological effect of DCs vaccine was 25.46 ± 3.02 and 27.52 ± 2.68. The kill rate of CTIL was higher than the CTL( P ＜ 0.05 ). Conclusion The kill rate of CTIL sensitized by DCs loaded autospecific lung cancer antigen is higher than CTL. It provides a new clue for biotherapy of lung cancer. Key words: Lung cancer; Dendritic cell; T lymphocyte; Kill rate

Potent Antitumor Effect of Interleukin-24 Gene in the Survivin Promoter and Retinoblastoma Double-Regulated Oncolytic Adenovirus

Interleukin (IL)-24 is an excellent therapeutic gene for cancer therapy. In this work, IL-24 was inserted into Ad.sp-E1A(Delta24), an oncolytic adenovirus with a 24-bp deletion in the E1A gene, which was driven by the survivin promoter to form Ad.sp-E1A(Delta24)-IL-24. Ad.sp-E1A(Delta24)-IL-24 has an excellent antitumor effect in vitro for human nasopharyngeal, liver, lung, and cervical carcinoma cell lines but does no or little damage to normal cell lines L-02 and WI38. Furthermore, it achieved nearly complete inhibition (although not elimination) of NCI-H460 lung carcinoma growth in nude mice. The antitumor efficacy of Ad.sp-E1A(Delta24)-IL-24 on NCI-H460 cells was clearly mediated by apoptosis, because it induced caspase-3 and poly(ADP-ribose) polymerase cleavage. This is the first report of Ad.sp-E1A(Delta24)-IL-24 with such an excellent, broad, and specific antitumor effect in vitro and nearly complete inhibition of lung tumor growth in vivo.

Dendritic Cells Derived from K562/A02 Cell Line Treated by Recombinant Adenovirus Encoding Human p53

Purpose Leukemia, a malignant tumor derived from hemotological system, belongs to a malignant clone disease of hemopoietic stem cell. Studies of immunology have indicated a close relationship between occurrence and development of leukemia and immunity of organism. Immunotherapy can completely clear up residual leukemic cells and cure the disease. The occurrence of multidrug resistance ( MDR ) is known for the main barrier of leukemia chemical therapy. And also, dendritic cells ( DCs ) are the most potent antigen-presenting cells for initiating cellular immune responses in vivo. DCs are attractive immunoregulatory cells for cancer immunotherapy, and their efficacy has been investigated in clinical trials. If we can induce multidrug resistant leukemic cell into a DC which is named with multidrug resistant leukemia-derived DC and promote its maturity with effective and harmless drugs, multidrug resistant leukemia-derived DC not only carries the special antigens of leukemia but also can present the special antigens to immune system to kill corresponding leukemic cells. At the same time, it can reverse indirectly leukemic multidrug resistance. Tumor suppressor gene p53 is pivotal in the regulation of apoptosis, and p53-based immunization is an attractive approach to cancer immunotherapy because of the mutant of p53 protein in malignant but not in normal cells. It has been shown that monocyte-derived human dendritic cells transduced with an adenoviral wild-type p53 (wt-p53) construct mediate the antitumor immune responses against p53-overexpressing tumor cells. We examined whether K562/A02 Cells -derived dendritic cells pulsed with the purified full-length wt-p53 protein were also capable of inducing the specific antitumor responses against K562/A02 cells in vitro.Methods P53 gene was transferred to monoclonal K562/A02 cells. P53 gene transcription was detected with RT-PCR. Proliferation test was conducted by using 3H-thymidine (3H-TdR) incorporation. Immature dendritic cells generated in the presence of interleukin-4 and granulocyte/macrophage colony-stimulating factor from K562/A02 cell line were transduced with an wt-p53. Uptake of p53 protein by dendritic cells was assessed by Western blotting. Induction of p53-specific CTL response was also evaluated by the cytotoxic assay against K562/A02 cells.Results Both Western blotting and and immunohistochemical analysis showed the accumulation of p53 protein in immature dendritic cells. T cells obtained from peripheral blood mononuclear cells of healthy volunteers were stimulated with wt-p53 and then applied to the cytotoxicity assay against the target cells-K562/A02. The CTL activity generated by adenoviral wt-p53-transduced dendritic cells was specific for K562/A02 cells.Conclusion Our results indicate that adenoviral wt-p53-transduced dendritic cells could induce the specific antitumor effect against the target tumor cells and that this in vitro model offers a new and more simple approach to the development of p53 and dendritic cellsbased immunogenetherapy. This offers a novel and promising immunogenetherapeutic srtategy to overcome multidrug resistant leukemia in the future.

Indomethacin Inhibits Cell Growth of Medullary Thyroid Carcinoma by Reducing Cell Cycle Progression into S Phase

Indomethacin, a non-steroidal anti-inflammatory drug (NSAID), has been reported to inhibit the growth of medullary thyroid carcinoma (MTC) cells in vitro. However, the mechanism of inhibition of MTC cell growth by indomethacin and its potency have yet to be revealed. We examined the effect of indomethacin on three different MTC cell lines (TT cells, DRO 81-1 cells and HRO 85-1 cells) and two non-MTC cells. The mechanism of indomethacin action in MTC cells was investigated by analyzing intracellular prostaglandin level, apoptosis, and cell cycle in TT cells. Indomethacin inhibited cell growth of all three MTC cell lines but not normal thyroid cells or anaplastic thyroid carcinoma cells. Indomethacin at 10 microM or greater showed a dose response inhibition of cell growth. Indomethacin at 25 muM, a putative therapeutic serum indomethacin level, showed potency similar to 100 to 200 nM sunitinib, a receptor tyrosine kinase inhibitor. To examine whether prostaglandin depletion might determine the inhibition of MTC cell growth, we created different prostaglandin E2 (PGE2) levels in TT cells using three different NSAIDs. A profound PGE2 depletion by indomethacin-ester, a potent cyclooxygenase (COX) II inhibitor, showed the least inhibition of cell growth. Indomethacin did not increase apoptosis of TT cells. Indomethacin, but not naproxen or indomethacin-ester, reduced cell cycle progression into S phase; this was unrelated to the degree of PGE2 depletion. The expression of phosphorylated retinoblastoma (pRb) protein that shifts cells from G(1) to S phase was reduced after exposure to indomethacin. In conclusion, indomethacin has specific anti-tumor effect on MTC cells, probably by reducing cell cycle progression into S phase rather than by prostaglandin depletion. Since no drug therapy is currently available for MTC, indomethacin may be one of the therapeutic candidates.

Specific anti-tumor effect induced by attenuated Salmonella typhimurium vaccine expressing extracellular region of vascular endothelial growth factor receptor 2

The purposes of this research were to study the stable expression of exogenous gene encoding therapeutic protein in attenuated Salmonella typhimurium, observe the metabolism of oral gene vaccine carried by attenuated Salmonella typhimuriums in BALB/c mouse, and investigate the feasibility of prevention and treatment of tumors by the recombinant bacteria. Recombinant plasmid pcDNA3.1+VEGFR2(n1–7) was stransformed into competent attenuated Salmonella typhimurium SL3261 to develop oral DNA vaccine SL3261-pcDNA3.1+VEGFR2(n1–7). To observe whether the exogenous gene can be expressed in the recombinant bacteria, PCR was performed to amplify the CMV promoter of the eukaryotic expression vector as the proof of stable expression of exogenous protein; transmission electron microscopy (TEM) was applied to observe the morphology of the recombinant bacteria to confirm that the exogenous gene has no impact on the growth of the bacteria, and then BALB/c mice were immunized with the gene vaccine. After inoculation of the gene vaccine, the recombinant bacteria SL3261 could be detected in the tissues such as small intestine, colon, liver and spleen. And then, mice in each group were challenged with tumor cells. The results of animal experiment showed that tumor growth of the mice in experimental group was inhibited and survival time of immunized mice was prolonged compared with control groups. A higher lymphocyte infiltration in tumors from animals treated with DNA vaccine was observed. Immunohistochemical analysis of tumor samples revealed an enhanced accumulation of CD8+ cytotoxic T lymphocytes, as well as an increase in CD4+ cells in the tumors of animals treated with the oral gene vaccine compared to tumors from control group mice. Ultrastructure of the tumor tissue showed that tumor cells in the samples of the immunized mice were well-differentiated. Our research confirmed that the exogenous gene can be stably expressed in the attenuated Salmonella typhimurium and has no impact on the growth of the recombinant bacteria; the exogenous gene can de delivered to the host by attenuated Salmonella typhimurium to produce anti-tumor effect with no obvious cytotoxity to the host. In this study, it is established that attenuated Salmonella typhimurium could be used as a vector for oral gene vaccine, and our study provided a theoretical basis for the body distribution and the metabolism of the recombinant bacteria. This strategy may provide a simple, safe and effective way for the prevention and treatment of tumors.

Direct and Natural Killer Cell-Mediated Antitumor Effects of Low-Dose Bortezomib in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) displays particular resistance to conventional cytostatic agents. Alternative treatment strategies focus on novel substances exhibiting antineoplastic and/or immunomodulatory activity enhancing for example natural killer (NK) cell antitumor reactivity. However, tumor-associated ligands engaging activating NK cell receptors are largely unknown. Exceptions are NKG2D ligands (NKG2DL) of the MHC class I-related chain and UL16-binding protein families, which potently stimulate NK cell responses. We studied the consequences of proteasome inhibition with regard to direct and NK cell-mediated effects against HCC. Primary human hepatocytes (PHH) from different donors, hepatoma cell lines, and NK cells were exposed to Bortezomib. Growth and viability of the different cells, and immunomodulatory effects including alterations of NKG2DL expression on hepatoma cells, specific induction of NK cell cytotoxicity and IFN-gamma production were investigated. Bortezomib treatment inhibited hepatoma cell growth with IC(50) values between 2.4 and 7.7 nmol/L. These low doses increased MICA/B mRNA levels, resulting in an increase of total and cell surface protein expression in hepatoma cells, thus stimulating cytotoxicity and IFN-gamma production of cocultured NK cells. Importantly, although NK cell IFN-gamma production was concentration-dependently reduced, low-dose Bortezomib neither induced NKG2DL expression or cell death in PHH nor altered NK cell cytotoxicity. Low-dose Bortezomib mediates a specific dual antitumor effect in HCC by inhibiting tumor cell proliferation and priming hepatoma cells for NK cell antitumor reactivity. Our data suggest that patients with HCC may benefit from Bortezomib treatment combined with immunotherapeutic approaches such as adoptive NK cell transfer taking advantage of enhanced NKG2D-mediated antitumor immunity.

Molecular mechanisms of specific anti-tumor effect and application of apoptin

凋亡素(apoptin)特异性抗肿瘤效应与其分子结构、在不同细胞的定位、磷酸化调节等多种因素相关.在动物模型实验中,apoptin诱导肿瘤凋亡没有明显的不良反应,是一种非常有潜力的抗肿瘤制剂。

Direct and Natural Killer Cell-Mediated Anti-Tumor Effects of Low-Dose Bortezomib in Hepatocellular Carcinoma.

Background & Aims: Hepatocellular carcinoma (HCC) displays a particular resistance to conventional cytostatic agents. Therefore, alternative treatment strategies focus on novel substances exhibiting anti-neoplastic and/or immunomodulatory activity enhancing for example Natural Killer (NK) cell anti-tumor reactivity. However, the tumor-associated ligands engaging activating NK cell receptors are largely unknown. Exceptions are the NKG2D ligands (NKG2DL) of the MIC and ULBP protein families, which potently stimulate NK cell responses. We studied the consequences of proteasome inhibition with regard to direct and NK cell-mediated effects against HCC.Methods: Primary human hepatocytes (PHH) from different donors, hepatoma cell lines and NK cells were exposed to Bortezomib. Growth and viability of hepatoma cells and PHH as well as immunomodulatory effects including alterations of NKG2DL expression on hepatoma cells, specific induction of NK cell cytotoxicity and IFN-γ production were investigated.Results: Bortezomib treatment inhibited hepatoma cell growth with IC50 values between 2.4 and 7.7 nanomol/liter. These low doses increased MICA/B mRNA levels and total and cell surface protein expression in hepatoma cells, which stimulated cytotoxicity and IFN-γ production of cocultured NK cells. Importantly, while IFN-γ production of NK cells was concentration-dependently reduced, low-dose Bortezomib neither induced NKG2DL expression or cell death in PHH nor altered NK cell cytotoxicity.Conclusions: Low-dose Bortezomib mediates a specific dual anti-tumor effect in HCC by inhibiting tumor cell proliferation and by priming hepatoma cells for NK cell anti-tumor reactivity. Our data suggest the clinical evaluation of Bortezomib treatment in HCC, especially in combination with immunotherapeutic approaches like adoptive NK cell transfer.

Dendritic cells loaded with XAGE-1b protein induce specific antitumor response against lung cancer

18080 Background: Dendritic cells (DCs) are the most potent antigen-presenting cells for initiating cellular immune response. Cancer-testis antigens (CTA) are the biggest tumor antigens family expressing only in some tumors and genital system but not in normal cells. XAGE-1b gene is one of CTA which highly expresses in lung cancer and has strong immunogenicity. Our study was to examine whether DCs loaded with XAGE-1b protein could induce specific antitumor response against lung cancer cells in vitro. Methods: Tumor tissues and normal lung tissues were obtained by operation from 30 non-small cell lung cancer patients. Cancer cells and normal lung epithelium cells were cultured and saved as target cells. Total RNA were isolated and RT-PCR was done to determine XAGE-1b gene expression. XAGE-1b gene was cloned by constructing expression vector and recombinant protein was expressed and purified by using BL21 (DE3) E. coli and AKTA-FPLC. Peripheral blood monocytes were isolated from 20ml blood and cultured to be DCs in serum-free DCs Medium. DCs were loaded with XAGE-1b protein through coculture and induced T lymphocytes into XAGE-1b-specific cytotoxic T lymphocytes (CTLs). The cytotoxicity of CTLs was then measured by cytotoxic assay. Results: 12/30(40%) lung cancer tissues expressed XAGE-1b gene, most of which were adenocarcinoma (11/12, 91.7%). None of normal tissues expressed it. Gene sequencing and western blot confirmed the expression vector construction and recombinant protein expression. Immunofluorescence identification showed the accumulation of XAGE-1b protein in immature DCs. T lymphocytes were stimulated twice with XAGE-1b protein-loaded DCs. Cytotoxic assay showed that the CTL cytotoxicity was much stronger for XAGE-1b positive tumor cells than for XAGE-1b negative tumor cells and it was almost none for normal lung epithelium cells. Conclusions: Our study indicates that DCs loaded with XAGE-1b protein could induce specific antitumor effect against lung cancer cells in vitro and this model offers a new approach to the immunotherapy for lung cancer. No significant financial relationships to disclose.

The Role of Enhanced Radiosensitivity and Tumor-specific Suicide Gene Vector in Genetherapy of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is one of the common malignant tumors in China. Radiotherapy and chemotherapy are the main therapy methods for NPC. To enhance the specific antitumor effect, a novel vector with radiosensitivity and tumor specificity was constructed in this study, which enables the reduction of dosage of radiation and chemotherapeutic drugs due to its double killing effect. Four DNA elements, Egr-1 promoter, Cytosine deaminase (CD) gene, hTERT promoter, Survivin antisense oligonucleotides were amplified and constructed in pcDNA3.1 vector. CD and Survivin gene expression in CNE-2 cells were detected by RT-PCR. High performance liquid chromatography (HPLC) was employed to determine the transformation from the prodrugs 5-FC to 5-FU. Hoechst33258 staining of the nuclei and methylthiazolyl tetrazolium(MTT) assay were applied to detect apoptosis and cell survivability, respectively. In addition, the anti-tumor effects were examined in vivo by injecting cells with different vectors into nude mice. Our results revealed a notable killing effect of combined treatment with 5-FC and radiation on CNE-2 cells transfected with vectors in vitro. This effect was especially notable on pEC-TS transferred cells, which showed 57% of cells were killed. In vivo, an obvious suppression of tumor was displayed in pEC-TS group, which was significantly different from other groups (p < 0.05). Consequently, this expression cassette may have a great therapeutic potential for the treatment of NPC.

Immunohistochemical expression of peripheral benzodiazepine receptors in human astrocytomas and its correlation with grade of malignancy, proliferation, apoptosis and survival

Peripheral benzodiazepine receptors (PBR) are widely distributed in peripheral tissues, astrocytes, and microglia of the brain. They are involved in apoptosis, proliferation, and many other processes, such as steroidogenesis in adrenal glands, male and female gonads, biological adaptation to stress, etc. It has been established that the expression of PBR in astrocytomas is higher than in the normal brain. The goal of this study was to explore the correlation of the immunohistochemical expression of PBR in astrocytomas with the grade of malignancy and rates of apoptosis, proliferation and survival. In 130 cases of astrocytomas (25 grade I, 25 grade II, 20 grade III, 60 grade IV), paraffin sections were stained immunohistochemically for PBR and MIB-1(Ki-67). TUNEL assay was used for evaluation of apoptosis. It was found that the intensity and extent of staining for PBR had a strong direct correlation with the grade of malignancy of the tumor, along with proliferative and apoptotic indices. The highest expression of PBR was in glioblastomas grade IV, especially around areas of necrosis. There was a strong negative correlation between PBR expression and survival. The results of this study may be applied in the pathological diagnosis of astrocytomas as an additional clue in establishing tumor grade; they may be used in the imaging of astrocytomas, both for diagnosis and follow-up, by the application of positron emission tomography scanning with PBR specific ligands. Targeting of PBR in high-grade gliomas may be a promising approach, achieving more specific anti-tumor effect.

Study of immunological effect of dendritic cell transfected with survivin gene on the specific anti-alimentary tract tumor

To investigate the effects of dendritic cells (DCs) transfected with survivin gene, and to observe the effective and specific anti-tumor immunological effect induced by modified DC in vitro. Survivin gene was transfected to DCs with liposomes. Survivin expression could be detected both in DCs cells and in cell culture with method of Western blot. Cytokines as well as cellular surface molecule such as IL-12, TNF-alpha, CD1 alpha, CD83, MHCII, CD80 and CD86 were detected. The competence of inducing human specific cytotoxic T lymphocyte (CTLs) was also detected with MTT. Survivin expression could be detected both in DCs which were transfected with survivin cDNA and in cell culture superior. The IL-12 and TNF-alpha level was (265.2 +/- 32.7), (437.1 +/- 83.5) pg/ml, and much higher in transgened DC cells than blank DC cells (P < 0.05). CD1 alpha, CD83, MHCII, CD80 and CD86 was high expressed in survivin-DC cells, however, it was low expressed in blank DC cells. The lyse rate to gastric cancer cell, colon cancer cell and bile duct cancer cell was 65%, 77%, and 85% respectively, and these were much higher than those of blank DC cells. DCs transfected with survivin gene could induce specific cytotoxic T lymphocytes and strikingly raised DC cell's antigen present function, and have specific CTL killing activity.