H.R. Kim

Concurrent delivery of GM-CSF and B7-1 using an oncolytic adenovirus elicits potent antitumor effect

Oncolytic adenoviral vectors are currently being developed as biologic anticancer agents. Coupling the lytic function of an oncolytic adenovirus (Ad) with its ability as a transgene delivery system represents a powerful extension of this methodology. A clear advantage is the amplification of a therapeutic gene, as replicating vectors would be able to infect and deliver the gene of interest to neighboring cells. Granulocyte–macrophage colony-stimulating factor (GM-CSF) is one of the most potent stimulators of a specific and long-lasting antitumor immunity and its important role in the maturation of antigen-presenting cells to induce T-cell activation has been well documented. Similarly, the B7 family has also been shown to play an integral role in mediating an antitumor response. Most tumor cells, however, lack the expression of these costimulatory molecules on their surface, thus escaping immune system recognition. To increase the antitumor effect of an oncolytic Ad, we have generated an E1B 55u2009kDa-deleted oncolytic adenoviral vector, YKL-GB, that expresses both GM-CSF and B7-1. The therapeutic efficacy of YKL-GB Ad was evaluated in immunocompetent mice bearing murine melanoma B16-F10 tumors. Significant inhibition of tumor growth was seen in mice treated with YKL-GB compared to those treated with the analogous vector, YKL-1. Moreover, YKL-GB oncolytic Ad demonstrated enhanced antitumor activity and higher incidences of tumor regression compared to a replication-incompetent Ad, dl-GB, which coexpresses GM-CSF and B7-1. Localized GM-CSF and B7-1 gene transfer also conferred long-lasting immunity against a tumor re-challenge. To establish that the observed antitumor effect is associated with the generation of a tumor-specific immune response, we carried out interferon-γ enzyme-linked immune spot assay. We observed that YKL-GB induced significantly higher immune cell activation than YKL-1. Furthermore, immunohistochemical studies demonstrated robust dendritic cells and CD4+/CD8+ T-cell infiltration in these mice compared to the YKL-1-treated groups. In agreement with these results, splenocytes from tumor-bearing mice treated with YKL-GB expressed high levels of the costimulatory and activation molecules. These findings demonstrate the effectiveness of enhancing the immune response against tumors with an oncolytic Ad expressing both GM-CSF and B7-1 and provide a potential therapeutic strategy for the management of neoplasia.

Short hairpin RNA-expressing oncolytic adenovirus-mediated inhibition of IL-8: effects on antiangiogenesis and tumor growth inhibition.

RNA interference, due to its target specificity, may be highly effective as a novel therapeutic modality, but direct delivery of synthetic small interfering RNA still remains a major obstacle for this approach. To induce long-term expression and specific gene silencing, novel delivery vector system is also required. In this study, we have generated an efficient oncolytic adenovirus (Ad)-based short hairpin (shRNA) expression system (Ad-ΔB7-U6shIL8) against IL-8, a potent proangiogenic factor. To demonstrate IL-8-specificity of this newly engineered Ad-based shRNA, we also manufactured replication-incompetent Ads (Ad-ΔE1-CMVshIL8 and Ad-ΔE1-U6shIL8) under the control of the cytomegalovirus (CMV) and U6 promoters, respectively. Ad-ΔE1-U6shIL8 was highly effective in reducing IL-8 expression, and was much more effective in driving IL-8-specific shRNA than the CMV promoter-driven vector. The reduced IL-8 expression then translated into decreased angiogenesis in vitro as measured by migration, tube formation and rat aortic ring sprouting assays. In addition to its effect on endothelial cells, Ad-ΔE1-U6shIL8 also effectively suppressed the migration and invasion of cancer cells. In vivo, intratumoral injection of Ad-ΔB7-U6shIL8 significantly inhibited the growth of Hep3B and A549 human tumor xenografts. Histopathological analysis of Ad-ΔB7-U6shIL8-treated tumors revealed an increase in apoptotic cells and a reduction in vessel density. Finally, Ad-ΔB7-U6shIL8 was also shown to inhibit the growth of disseminated MDA-MB-231 breast cancer metastases. Taken together, these findings demonstrate the utility and antitumor effectiveness of oncolytic Ad expressing shRNA against IL-8.

The frequency and impact of ROS1 rearrangement on clinical outcomes in never smokers with lung adenocarcinoma

BACKGROUNDnTo determine the frequency and predictive impact of ROS1 rearrangements on treatment outcomes in never-smoking patients with lung adenocarcinoma.nnnPATIENTS AND METHODSnWe concurrently analyzed ROS1 and ALK rearrangements and mutations in the epidermal growth factor receptor (EGFR), and KRAS in 208 never smokers with lung adenocarcinoma. ROS1 and ALK rearrangements were identified by fluorescent in situ hybridization.nnnRESULTSnOf 208 tumors screened, 7 (3.4%) were ROS1 rearranged, and 15 (7.2%) were ALK-rearranged. CD74-ROS1 fusions were identified in two patients using reverse transcriptase-polymerase chain reaction. The frequency of ROS1 rearrangement was 5.7% (6 of 105) among EGFR/KRAS/ALK-negative patients. Patients with ROS1 rearrangement had a higher objective response rate (ORR; 60.0% versus 8.5%; P = 0.01) and a longer median progression-free survival (PFS; not reached versus 3.3 months; P = 0.008) to pemetrexed than those without ROS1/ALK rearrangement. The PFS to EGFR-tyrosine kinase inhibitors in patients harboring ROS1 rearrangement was shorter than those without ROS1/ALK rearrangement (2.5 versus 7.8 months; P = 0.01).nnnCONCLUSIONSnThe frequency of ROS1 rearrangements in clinically selected patients is higher than that reported for unselected patients, suggesting that ROS1 rearrangement is a druggable target in East-Asian never smokers with lung adenocarcinoma. Given the different treatment outcomes to conventional therapies and availability of ROS1 inhibitors, identification of ROS1 rearrangement can lead to successful treatment in ROS1-rearranged lung adenocarcinomas.

Multicentre phase II trial of bevacizumab combined with docetaxel–carboplatin for the neoadjuvant treatment of triple-negative breast cancer (KCSG BR-0905)

BACKGROUNDnThis phase II neoadjuvant trial evaluated bevacizumab-docetaxel and carboplatin in triple-negative breast cancer.nnnPATIENTS AND METHODSnWomen with hormone receptor- and human epidermal growth factor receptor 2 (HER2)-negative, stage II/III breast cancer received six cycles of 75 mg/m(2) docetaxel, carboplatin (AUC = 5) and 15 mg/kg bevacizumab every 21 days. The primary end point was pathological complete response (pCR) in breasts and axillary lymph nodes (ALN).nnnRESULTSnForty-five patients were recruited from the Korean Cancer Study Group. The median age was 45 (range 30-72) years. ALNs were positive in 80% of patients (n = 36) at diagnosis. Overall, 98% of patients (n = 44) completed therapy and underwent surgery. The pCR rate was 42% (n = 19); clinical response rate 96% (n = 43); complete 13% (n = 6); partial 82% (n = 37); stable disease 2% (n = 1). Breast-conserving surgery was undertaken in 78% of patients (n = 35). Most frequent grade 3/4 adverse events were neutropenia (84%, n = 38) and febrile neutropenia (9%, n = 4). One patient experienced delayed wound healing after surgery.nnnCONCLUSIONSnNeoadjuvant bevacizumab, docetaxel and carboplatin resulted in an encouraging pCR rate and negligible wound healing problems after surgery.

Co-clinical trials demonstrate predictive biomarkers for dovitinib, an FGFR inhibitor, in lung squamous cell carcinoma

BackgroundnWe conducted co-clinical trials in patient-derived xenograft (PDX) models to identify predictive biomarkers for the multikinase inhibitor dovitinib in lung squamous cell carcinoma (LSCC).nnnMethodsnThe PDX01-02 were established from LSCC patients enrolled in the phase II trial of dovitinib (NCT01861197) and PDX03-05 were established from LSCC patients receiving surgery. These five PDX tumors were subjected to in vivo test of dovitinib efficacy, whole exome sequencing and gene expression profiling.nnnResultsnThe PDX tumors recapitulate histopathological properties and maintain genomic characteristics of originating tumors. Concordant with clinical outcomes of the trial enrolled-LSCC patients, dovitinib produced substantial tumor regression in PDX-01 and PDX-05, whereas it resulted in tumor progression in PDX-02. PDX-03 and -04 also displayed poor antitumor efficacy to dovitinib. Mutational and genome-wide copy number profiles revealed no correlation between genomic alterations of FGFR1-3 and sensitivity to dovitinib. Of note, gene expression profiles revealed differentially expressed genes including FGF3 and FGF19 between PDX-01 and 05 and PDX-02-04. Pathway analysis identified two FGFR signaling-related gene sets, FGFR ligand binding/activation and SHC-mediated cascade pathway were substantially up-regulated in PDX-01 and 05, compared with PDX-02-04. The comparison of gene expression profiles between dovitinib-sensitive versus -resistant lung cancer cell lines in the Cancer Cell Line Encyclopedia database also found that transcriptional activation of 18u2009key signaling components in FGFR pathways can predict the sensitivity to dovitinib both in cell lines and PDX tumors. These results highlight FGFR pathway activation as a key molecular determinant for sensitivity to dovitinib.nnnConclusionsnFGFR gene expression signatures are predictors for the response to dovitinib in LSCC.

Allergen‐specific immunotherapy induces regulatory T cells in an atopic dermatitis mouse model

Several studies have demonstrated that allergen‐specific immunotherapy (SIT) can be an effective treatment for atopic dermatitis (AD). However, there is no relevant mouse model to investigate the mechanism and validate the novel modality of SIT in AD.