Synergistic effect of the anti-HER-2/neu antibody and cisplatin in immortalized and primary mesothelioma cell lines

Systematic Analysis of Aberrant Biochemical Networks and Potential Drug Vulnerabilities Induced by Tumor Suppressor Loss in Malignant Pleural Mesothelioma

Background: Malignant pleural mesothelioma (MPM) is driven by the inactivation of tumor suppressor genes (TSGs). An unmet need in the field is the translation of the genomic landscape into effective TSG-specific therapies. Methods: We correlated genomes against transcriptomes of patients' MPM tumors, by weighted gene co-expression network analysis (WGCNA). The identified aberrant biochemical networks and potential drug targets induced by tumor suppressor loss were validated by integrative data analysis and functional interrogation. Results: CDKN2A/2B loss activates G2/M checkpoint and PI3K/AKT, prioritizing a co-targeting strategy for CDKN2A/2B-null MPM. CDKN2A deficiency significantly co-occurs with deletions of anti-viral type I interferon (IFN-I) genes and BAP1 mutations, that enriches the IFN-I signature, stratifying a unique subset, with deficient IFN-I, but proficient BAP1 for oncolytic viral immunotherapies. Aberrant p53 attenuates differentiation and SETD2 loss acquires the dependency on EGFRs, highlighting the potential of differentiation therapy and pan-EGFR inhibitors for these subpopulations, respectively. LATS2 deficiency is linked with dysregulated immunoregulation, suggesting a rationale for immune checkpoint blockade. Finally, multiple lines of evidence support Dasatinib as a promising therapeutic for LATS2-mutant MPM. Conclusions: Systematic identification of abnormal cellular processes and potential drug vulnerabilities specified by TSG alterations provide a framework for precision oncology in MPM.

Potentiation of high-LET radiation by gemcitabine: targeting HER2 with trastuzumab to treat disseminated peritoneal disease

PURPOSE

Recent studies from this laboratory with (212)Pb-trastuzumab have shown the feasibility of targeted therapy for the treatment of disseminated peritoneal disease using (212)Pb as an in vivo generator of (212)Bi. The objective of the studies presented here was improvement of the efficacy of alpha-particle radioimmunotherapy using a chemotherapeutic agent.

EXPERIMENTAL DESIGN

In a series of experiments, a treatment regimen was systematically developed in which athymic mice bearing i.p. LS-174T xenografts were injected i.p. with gemcitabine at 50 mg/kg followed by (212)Pb radioimmunotherapy.

RESULTS

In a pilot study, tumor-bearing mice were treated with gemcitabine and, 24 to 30 h later, with 5 or 10 muCi (212)Pb-trastuzumab. Improvement in median survival was observed at 5 microCi (212)Pb-trastuzumab in the absence (31 days) or presence (51 days) of gemcitabine: 45 and 70 days with 10 microCi versus 16 days for untreated mice (P < 0.001). Multiple doses of gemcitabine combined with a single (212)Pb radioimmunotherapy (10 microCi) administration was then evaluated. Mice received three doses of gemcitabine: one before (212)Pb-trastuzumab and two afterwards. Median survival of mice was 63 versus 54 days for those receiving a single gemcitabine dose before radioimmunotherapy (P < 0.001), specifically attributable to (212)Pb-trastuzumab (P = 0.01). Extending these findings, one versus two treatment cycles was compared. A cycle consisted of sequential treatment with gemcitabine, 10 microCi (212)Pb radioimmunotherapy, then one or two additional gemcitabine doses. In the first cycle, three doses of gemcitabine resulted in a median survival of 90 versus 21 days for the untreated mice. The greatest benefit was noted after cycle 2 in the mice receiving 10 microCi (212)Pb-trastuzumab and two doses of gemcitabine with a median survival of 196.5 days (P = 0.005). Pretreatment of tumor-bearing mice with two doses of gemcitabine before (212)Pb radioimmunotherapy was also assessed with gemcitabine injected 72 and 24 h before (212)Pb-trastuzumab. The median survival was 56 and 76 days with one and two doses of gemcitabine versus 49 days without gemcitabine. The effect may not be wholly specific to trastuzumab because (212)Pb-HuIgG with two doses of gemcitabine resulted in a median survival of 66 days (34 days without gemcitabine).

CONCLUSIONS

Treatment regimens combining chemotherapeutics with high-LET targeted therapy may have tremendous potential in the management and care of cancer patients.

Combination treatment of glioblastoma multiforme cell lines with the anti-malarial artesunate and the epidermal growth factor receptor tyrosine kinase inhibitor OSI-774

New drugs and combination modalities for otherwise non-responsive brain tumors are urgently required. The anti-malarial artesunate (ART) and the EGFR tyrosine kinase inhibitor OSI-774 reveal profound cytotoxic activity. The effectiveness of a combination treatment and the underlying molecular determinants of cellular response are unknown. In the present investigation, we studied ART and OSI-774 in glioblastoma multiforme (GBM) cell lines. Supra-additive inhibition of cell growth was observed in U-87MG.DeltaEGFR cells transduced with a deletion-mutant constitutively active EGFR gene, while additive effects were present in cells transduced with wild-type EGFR (U-87MG.WT-2N), kinase-deficient EGFR (U-87MG.DK-2N), mock vector controls (U-87MG.LUX), or non-transduced parental U-87MG cells. Among nine other non-transduced GBM cell lines, supra-additive effects were found in two cell lines (G-210GM, G-599GM), while ART and OSI-774 acted in an additive manner in the other seven cell lines (G-211GM, G-750GM, G-1163GM, G-1187GM, G-1265GM, G-1301GM, and G-1408GM). Sub-additive or antagonistic effects were not observed. Genomic gains and losses of genetic material in the non-transduced cell lines as assessed by comparative genomic hybridization were correlated with the IC(50) values for ART and OSI-774 and subsequently subjected to hierarchical cluster analysis and cluster image mapping. A genomic profile of imbalances was detected that predicted cellular response to ART and OSI-774. The genes located at the genomic imbalances of interest may serve as candidate resistance genes of GBM cells towards ART and OSI-774. In conclusion, the combination treatment of ART and OSI-774 resulted in an increased growth inhibition of GBM cell lines as compared to each drug alone.