Gene therapy for lung cancer

CLEC12B suppresses lung cancer progression by inducing SHP-1 expression and inactivating the PI3K/AKT signaling pathway

Lung cancer is the leading cause of cancer mortality worldwide. CLEC12B, a C-type lectin-like receptor, is low-expressed in lung cancer tissues. However, the function of CLEC12B in lung cancer and its underlying mechanism remain unclear. Here, an obvious down-regulation of CLEC12B was observed in lung cancer cells compared with the normal lung epithelial cells. CLEC12B over-expression suppressed cell viability and cell cycle entry in lung cancer, along with the reduction of PCNA and cyclin D1 expressions, while silencing CLEC12B possessed the opposite effects. Over-expression of CLEC12B promoted lung cancer cell apoptosis, accompanied by decreased Bcl-2 and increased Bax, cleaved caspase-3 and cleaved caspase-9. Moreover, CLEC12B decreased phosphorylation of PI3K-p85 and AKT proteins. By contrast, CLEC12B knockdown activated the PI3K/AKT pathway. In vivo, CLEC12B inhibited tumor growth in lung cancer, which can be reversed by CLEC12B inhibition. Co-IP and immunofluorescence assays confirmed the interaction between CLEC12B and SHP-1, and CLEC12B over-expression increased SHP-1 level. Furthermore, knocking down SHP-1 abrogated the above biological phenotypes caused by CLEC12B elevation. Taken together, our findings demonstrate that CLEC12B serves as a tumor-suppressing gene in lung cancer through positively regulating SHP-1 expression, which may be mediated by the PI3K/AKT signaling pathway.

Cisplatin Synergistically Enhances Antitumor Potency of Conditionally Replicating Adenovirus via p53 Dependent or Independent Pathways in Human Lung Carcinoma

Cisplatin is ranked as one of the most powerful and commonly prescribed anti-tumor chemotherapeutic agents which improve survival in many solid tumors including non-small cell lung cancer. However, the treatment of advanced lung cancer is restricted due to chemotherapy resistance. Here, we developed and investigated survivin promoter regulating conditionally replicating adenovirus (CRAd) for its anti-tumor potential alone or in combination with cisplatin in two lung cancer cells, H23, H2126, and their resistant cells, H23/CPR, H2126/CPR. To measure the expression of genes which regulate resistance, adenoviral transduction, metastasis, and apoptosis in cancer cells, RT-PCR and Western blotting were performed. The anti-tumor efficacy of the treatments was evaluated through flow cytometry, MTT and transwell assays. This study demonstrated that co-treatment with cisplatin and CRAd exerts synergistic anti-tumor effects on chemotherapy sensitive lung cancer cells and monotherapy of CRAd could be a practical approach to deal with chemotherapy resistance. Combined treatment induced stronger apoptosis by suppressing the anti-apoptotic molecule Bcl-2, and reversed epithelial to mesenchymal transition. In conclusion, cisplatin synergistically increased the tumor-killing of CRAd by (1) increasing CRAd transduction via enhanced CAR expression and (2) increasing p53 dependent or independent apoptosis of lung cancer cell lines. Also, CRAd alone proved to be a very efficient anti-tumor agent in cancer cells resistant to cisplatin owing to upregulated CAR levels. In an exciting outcome, we have revealed novel therapeutic opportunities to exploit intrinsic and acquired resistance to enhance the therapeutic index of anti-tumor treatment in lung cancer.

Induction of antitumor immunity by transduction of CD40 ligand gene and interferon-gamma gene into lung cancer

CD40-CD40 ligand (CD40L) interaction is an important costimulatory signaling pathway in the crosstalk between T cells and antigen-presenting cells. This receptor-ligand system is known to be essential in eliciting strong cellular immunity. Here we demonstrate that murine lung cancer cells (3LLSA) transduced with the CD40L gene (3LLSA-CD40L) were rejected in syngeneic C57BL/6 mice, but grew in CD40-deficient mice to the same extent as control tumor cells. Immunohistochemical study showed that inflammatory cells, including CD4+, CD8+ T cells and NK cells, infiltrated into the inoculated 3LLSA-CD40L tumor tissue. Inoculation of 3LLSA-CD40L cells into mice resulted in the induction of 3LLSA-specific cytotoxic T-cell immunity, and the growth of parental 3LLSA tumors was inhibited when 3LLSA cells were inoculated into C57BL/6 mice mixed with 3LLSA-CD40L cells or when they were rechallenged 4 weeks after 3LLSA-CD40L cells were rejected. Furthermore, co-inoculation of interferon (IFN)-gamma-transduced cells (3LLSA-IFNgamma) with 3LLSA-CD40L cells enhanced the antitumor immunity efficiently in vivo. These results indicate that the in vivo priming with CD40L- and IFN-gamma gene-transduced lung cancer cells is a promising strategy for inducing antitumor immunity in the treatment of lung cancer.

Enhancement of natural killer cell-mediated cytotoxicity by coexpression of GM-CSF/B70 in hepatoma

On investigating the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) and costimulatory molecule, B70, in antitumor immunity, we have found important effects of GM-CSF/B70 coexpression in the interaction with natural killer (NK) cells. We used the pLSN vector system to contain the neomycin-resistant gene and LTR promoter. The pLSNGM-CSF, pLSNB70 and pLSNB70/GM-CSF, pLSN vectors each containing GM-CSF, B70, and B70/GM-CSF cDNA, respectively, were constructed. They were transfected into human hepatocellular carcinoma cell (SK-HEP1), and stable cells (SK-pLSN, SK-GM, SK-B70 and SK-BG) were selected after neomycin treatment. According to enzyme-linked immunosorbent analysis and FACS, we showed that expression of GM-CSF was increased up to 23-fold in SK-GM and SK-BG cells, and also expression of B70 was induced at least 76-97% in SK-B70 and SK-BG cells. Expression of B70 was remarkably increased by autocrine effect of GM-CSF in SK-BG cells. Primary cytolytic ability of GM-CSF and B70 significantly increased almost 4-fold (effector/target ratio, 100:1) in SK-BG cells. In in vivo studies, SK-BG cells showed much less subcutaneous tumor formation in nude mice accompanying increased NK cell proliferation and cytotoxicity. Therefore, these results suggest that combining expression of GM-CSF and B70 may enhance NK-mediated cytotoxicity, and then induce the antitumor immunity in hepatoma transplanted into nude mice.

Intravascular and endobronchial DNA delivery to murine lung tissue using a novel, nonviral vector

Gene transfer to the lung can be achieved via either the airway or the pulmonary vasculature. We evaluated gene transfer and expression by intravascular and endobronchial routes, using DNA complexed with G9 PAMAM dendrimer or naked plasmid DNA. Intravascular tail vein delivery of dendrimer-complexed pCF1CAT plasmid resulted in high levels of transgene expression in the lung at 12 and 24 hr, followed by a second peak of expression 3 to 5 days after administration. After intravenous administration of the complexes, CAT expression was never observed in organs other than the lung. There were only minimal levels of CAT protein expressed in the lung after intravenous administration of naked plasmid DNA. Repeated intravascular doses of the dendrimer-complexed plasmid, administered four times at 4-day intervals, maintained expression at 15-25% of peak concentrations achieved after the initial dose. Endobronchial delivery of naked pCF1CAT plasmid produced significant amounts of CAT protein in the lung. Comparison of intratracheal and intranasal routes resulted in similar expression levels of CAT in the lung and trachea. However, in juxtaposition to vascular delivery, intranasal delivery of dendrimer-complexed plasmid DNA gave lower levels of CAT expression than that observed with naked plasmid DNA. In situ localization of CAT enzymatic activity suggested that vascular administration seemed to achieve expression in the lung parenchyma, mainly within the alveoli, while endobronchial administration primarily targeted bronchial epithelium. Our results show that intravenously administered G9 dendrimer is an effective vector for pulmonary gene transfer and that transgene expression can be prolonged by repeated administration of dendrimer-complexed DNA.

Gene Therapy for Lung Cancer

Gene therapy is emerging as a promising modality for the treatment of lung cancer. Diverse strategies employing gene therapy for lung cancer have been investigated in vitro and in animal models, and a number of these approaches have met with promising results. Several phase I and II clinical trials have been undertaken, and early results suggest that it may be safe to administer gene therapy to lung cancer patients. It remains to be determined whether this modality will be efficacious as primary or adjunctive therapy in the setting of lung cancer.

Effective genetic therapy of established medullary thyroid carcinomas with murine interleukin-2: dissemination and cytotoxicity studies in a rat tumor model

Replication-defective adenovirus (AdCMVmIL2) expressing murine interleukin-2 was directly injected into rat medullary thyroid carcinomas to examine antitumor activity. AdCMVmIL2 cured 42.9% of all treated tumor bearing animals. Most cured rats were protected against tumor growth after subsequent rechallenge with wild-type tumor cells, reflecting the immunity obtained from the original treatment. Studies of viral dissemination showed that the intratumoral inoculated viruses can enter the circulation, infect peripheral tissues, and express genes driven by the CMV promoter. Liver is the main target organ. In a toxicity study, AdCMVmIL2 was administered i.v. at a dose five times higher than that given directly into tumor. No detectable side effect was found. Histological studies showed variable degrees of lymphocyte infiltration in the livers of studied animals, and no functional change indicated by the normal serum level of glutamic oxalacetic transaminase and glutamic pyruvic transaminase was found in all animals studied. These data demonstrate that AdCMVmIL2 is an effective antitumor agent in this animal model, and that virus treatment can be given without significant toxicity to other organs.

Bystander tumoricidal effect and gap junctional communication in lung cancer cell lines

Tumor cells expressing the herpes simplex virus-thymidine kinase (HSV-tk) gene become sensitive to ganciclovir (GCV), and the phenomenon by which tumor cells surrounding the HSV-tk expressing cells also become sensitive to GCV is known as the "bystander effect." The purpose of this study was to investigate the bystander effect in human lung-cancer cell lines, and the role of gap-junctional intercellular communication as the mechanism responsible for it. Gap-junctional intercellular communication was measured both with a dye-transfer assay involving single-cell microinjection of Lucifer Yellow and with a PKH26/calcein-AM double-dye-transfer assay. Significant bystander tumoricidal effect was observed in lung-cancer cell lines when cultured cells contained only 10% HSV-tk expressing cells. This was also observed to occur with cell lines of different origin or from different species. Although gap-junctional intercellular communication characterized by rapid transfer of Lucifer Yellow was not observed, we did detect gap-junctional communication marked by the slow transfer of calcein-AM in lung-cancer cell lines. However, neither an inhibitor (1-octanol) nor an enhancer (all trans-retinoic acid [ATRA]) of gap-junctional communication affected the extent of the bystander effect. These findings suggest that low levels of gap-junctional communication may be efficient for producing the bystander effect in lung-cancer cells, or that other mechanisms may underlie this effect. Although gap-junctional communication may play an important role in generating the bystander effect in tumor cells expressing the HSV-tk gene, further knowledge of the mechanism of this effect may help improve the treatment of lung cancer with an HSV-tk system.

Genetic immunotherapy of established tumors with adenovirus-murine granulocyte-macrophage colony-stimulating factor

Increased local production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by genetically modified tumor cells can induce specific antitumor cellular immunity. We constructed a recombinant adenovirus expressing murine GM-CSF and tested it for therapeutic efficacy in a syngeneic murine lung cancer model system. In vitro transduction of Lewis lung carcinoma cells with adenovirus-mGM-CSF suppressed tumor formation in syngenic mice (C57BL/6), and transduced and irradiated Lewis lung carcinoma cells induced regression of pre-established wild-type tumors without in vitro selection for transductants. Low, but significant, levels of specific antitumor cytotoxic T lymphocytes (CTL) were observed in mice inoculated with GM-CSF but not with reporter virus-transduced tumor cells. GM-CSF-transduced cells induced the accumulation of dendritic cells at the site of tumor, consistent with a mechanism involving improved tumor antigen presentation. These data suggest that transduction of tumor cells with recombinant GM-CSF adenovirus may be an effective and practical cancer gene therapeutic strategy.

Dose-intense therapy with etoposide, ifosfamide, cisplatin, and epirubicin (VIP-E) in 100 consecutive patients with limited- and extensive-disease small-cell lung cancer

BACKGROUND

We conducted a phase I/II trial to assess the feasibility and activity of VIP-E chemotherapy in small-cell lung cancer. End-points were treatment-related morbidity and mortality, response to treatment. duration of response, and survival.

PATIENTS AND METHODS

Two cycles of combination chemotherapy followed by granulocyte colony-stimulating factor (G-CSF) were given at a dose of etoposide (500 mg/m2), ifosfamide (4000 mg/m2), cisplatin (50 mg/m2), and epirubicin (50 mg/m2) to 100 consecutive patients with SCLC. Thirty patients (19 with LD, and 11 with ED SCLC) proceeded to VIC-E high-dose chemotherapy with autologous peripheral blood stem cell transplantation (PBSCT) at a cumulative dose of etoposide 1500 mg/m2, ifosfamide 12,000 mg/m2, carboplatin 750 mg/m2 and epirubicin 150 mg/m2 (VIC-E). Surgical resection of primary tumor was attempted at the earliest feasible point. Thoracic irradiation was given after completion of chemotherapy. RESULTS of conventional-dose VIP-E: 97 patients were evaluable for response. Objective response rate was 81% in LD-SCLC (33% CR, 48% PR; excluding patients in surgical CR) and 77% in ED-SCLC (18% CR, 58% PR). Treatment mortality was 2%. Median survival was 19 months in LD-SCLC and 6 months in ED-SCLC. Two-year survival was 36% in LD and 0% in ED SCLC. RESULTS OF HIGH-DOSE VIC-E: All 30 patients improved on or maintained prior responses. Four patients (13%) died of treatment-related complications. Median survival was 26 months in LD-SCLC and 8 months in ED-SCLC. Two-year survival was 53% in LD and 9% in ED SCLC.

CONCLUSION

VIP-E chemotherapy is an effective induction therapy for SCLC. Compared with traditional protocols such as ACO or carboplatin/etoposide, response rates are slightly improved, while survival is not different. In the LD SCLC subgroup, high-dose chemotherapy improved response rates and survival, especially for patients in surgical CR prior to high-dose therapy. In ED SCLC, however, higher response-rates did not translate into improved survival. Selected LD-SCLC patients with good partial or complete remissions after prior therapy may benefit from HDC and PBSCT.

Dose-intense therapy with etoposide, ifosfamide, cisplatin, and epirubicin (VIP-E) in 107 consecutive patients with limited- and extensive-stage non-small-cell lung cancer

BACKGROUND

We conducted a phase I/II trial to assess the feasibility and activity of combination chemotherapy with etoposide, ifosfamide, cisplatin, and epirubicin in limited-stage (LS, stage I-IIIB) and extensive-stage (ES, stage IV) non-small-cell lung cancer (NSCLC). End-points were treatment-related morbidity and mortality, response rate, duration of response, and survival.

PATIENTS AND METHODS

Chemotherapy followed by granulocyte colony-stimulating factor was given at a dose of etoposide (500 mg/m2), ifosfamide (4000 mg/m2), cisplatin (50 mg/m2), and epirubicin (50 mg/m2) (VIP-E) to 107 patients with NSCLC. Twenty-five patients with qualifying responses proceeded to high-dose chemotherapy with autologous peripheral blood stem cell transplantation after etoposide (1500 mg/m2), ifosfamide (12,000 mg/m2), carboplatin (750 mg/m2) and epirubicin (150 mg/m2) (VIC-E) conditioning. RESULTS OF CONVENTIONAL-DOSE VIP-E: 35 of 102 (34%) evaluable patients responded (2 CR's, 33 PR's), 33/102 patients (33%) showed no change (NC); the remainder of patients progressed with therapy (PD). Objective response rate was 68% (4% CR, 64% PR) in LS-NSCLC and 23% (1.4% CR, 21.4% PR) in ES-NSCLC. Median duration of survival was 13 months in LS-NSCLC and 5.5 months in ES-NSCLC. Two-year survival was 26% in LS and 2% in ES-NSCLC. RESULTS OF HIGH-DOSE VIC-E: 23 of 24 evaluable patients improved or maintained prior responses (92%), I patient showed NC. Treatment mortality was 4%. Median duration of survival was 17 months in LS-NSCLC and 10 months in ES-NSCLC. Two-year survival was 30% in LS and 8% in ES-NSCLC.

CONCLUSION

Response-rates and survival after conventional-dose VIP-E chemotherapy are comparable to other published trials of combination chemotherapy in NSCLC. Toxicity and mortality is acceptable in limited stage, but unacceptably high in extensive stage NSCLC. Although better response-rates were achieved in the high-dose arm, they did not translate into improved survival. Most stage IV NSCLC-patients will neither benefit from VIP-E conventional dose, nor from VIC-E high dose chemotherapy. Whether selected LS-patients with partial or complete responses to VIP-E induction chemotherapy could benefit from dose intensification in an adjuvant or neo-adjuvant setting remains to be determined.