Faculty Bibliography

The 1995 Lung Cancer Study Group consensus recommending lobectomy for stage I non-small cell lung cancer (NSCLC) has directed lung cancer resections since its publication. However, enhancements in imaging technology over the last decade have produced larger cohorts of patients presenting with localized, early-stage disease. Today, multislice computer tomography is widely available, capable of detecting NSCLC at smaller sizes, with improved spatial resolution, and is used in screening programs for high-risk individuals. Furthermore, the maturation of minimally invasive surgical resection (video-assisted thoracoscopic surgery) has reduced perioperative morbidity and mortality, improved postoperative lung function, and demonstrated equivalent oncologic effectiveness to open surgery. The mandatory use of lobectomy for patients with small stage IA NSCLC is now being challenged. Numerous single-institution trials have demonstrated that well-selected use of sublobar resection can afford comparable survival and recurrence rates to lobectomy, particularly in high-risk patients. Currently, a prospective, randomized multi-institutional phase III trial is being conducted by the Cancer and Lymphoma Group B (CALGB 140503) to determine whether patients with small (< or =2 cm) peripheral NSCLC tumors can safely undergo sublobar resection while maintaining rates of survival and recurrence that are comparable to lobectomy. This review summarizes the literature from the past 15 years to assist in applying those conclusions to future research innovation

INTRODUCTION: Osteopontin (OPN) is a multifunctional protein with an important but poorly understood role in non-small cell lung cancer (NSCLC) pathogenesis. Moreover, the role of the three known mRNA isoforms (OPNa, OPNb, and OPNc) has not been reported. We hypothesize that OPN isoforms play different roles in determining the metastatic potential of NSCLC. METHODS: We amplified mRNA for each OPN isoform in NSCLC tumors and matched normal lung. The functional impact of each isoform was evaluated by transfecting cDNA plasmids specific to each isoform into NSCLC cell lines and comparing behavior to empty vector controls in scratch closure, cell proliferation, soft-agar colony formation, and Matrigel invasion assays. Gene array was used to evaluate differences in downstream targets and was compared with a panel of markers for epithelial-mesenchymal transition (EMT). RESULTS: OPNa expression was increased in 91% of NSCLC tumors compared with matched lung. OPNa overexpression significantly increased activity in scratch closure, proliferation, soft-agar colony formation, and Matrigel invasion assays compared with controls in all cell lines. OPNb overexpression produced a less significant modulation of function. OPNc overexpression significantly decreased activity in proliferation, colony formation, and invasion assays compared with controls. Expression arrays revealed an increase in EMT with OPNa overexpression but not OPNc. Differences were validated by quantitative reverse transcriptase-polymerase chain reaction. CONCLUSIONS: Overexpression of the individual OPN isoforms in NSCLC results in divergent functional phenotypes. OPNa produced an aggressive phenotype, whereas OPNc produced a more indolent phenotype. Exon 4, which is transcribed in OPNa but absent in OPNc, may be central to this phenomenon and could serve as a target for isoform-specific inhibition of OPN in NSCLC

SV40 has been detected prevalently in a limited panel of human tumors: mesothelioma, bone and brain tumors, and lymphoma. These are the same tumor types that are specifically induced by SV40 when injected into hamsters, a finding that has raised concerns about the possible pathogenic role of SV40 in humans. Two different SV40 isolates differing in the number of 72-bp elements in the virus regulatory region, archetypal SV40 (1ESV40), which contains one 72 bp, and nonarchetypal SV40 (wtSV40), which contains two 72 bp, have been detected in human tumors. 1ESV40 has been prevalently detected in brain tumors, with wtSV40 prevalently in mesothelioma. The apparent different cell tropism could be related to the virus (i.e., possibly to the number of 72-bp elements) and to different expression of cellular genes, known to play a critical role in SV40-mediated transformation of human cells, such as Notch-1 and c-Met. To test for possible differences in tissue tropism, we infected primary human mesothelial cells (HM) and primary human astrocytes (Ast) with 1ESV40 and with wtSV40 from 2 different SV40 strains, 776 and Baylor. All viruses transformed astrocytes; only wtSV40 transformed HM. Intracellular signaling of c-Met and Notch-1 was differently induced by these 2 viruses in HM and Ast. Differences in Notch-1 expression and signaling (i.e., downstream effectors, c-Myc, HEY-1, HES-1, and HEY-L) appeared to influence SV40-mediated transformation of primary astrocytes and mesothelial cells. Our results provide a biological rationale to the observation that 1ESV40 is prevalently detected in brain tumors and wtSV40 in mesotheliomas

Asbestos fibers cause chronic inflammation that may be critical to the development of malignant mesothelioma (MM). Two human MM cell lines (Hmeso, PPM Mill) were used in a SCID mouse xenograft model to assess time-dependent patterns of inflammation and tumor formation. After intraperitoneal (IP) injection of MM cells, mice were euthanized at 7, 14, and 30 days, and peritoneal lavage fluid (PLF) was examined for immune cell profiles and human and mouse cytokines. Increases in human MM-derived IL-6, IL-8, bFGF, and VEGF were observed in mice at 7 days postinjection of either MM line, and a striking neutrophilia was observed at all time points. Free-floating tumor spheroids developed in mice at 14 days, and both spheroids and adherent MM tumor masses occurred in all mice at 30 days. Results suggest that inflammation and cytokine production precede and may be critical to the development of MMs

INTRODUCTION: Thoracic malignancies and human breast cancer (HBC) continue to be aggressive solid tumors that are poor responders to the existing conventional standard chemotherapeutic approaches. Malignant pleural mesothelioma (MPM) is an asbestos-related tumor of the thoracic pleura that lacks effective treatment options. Altered ubiquitin proteasome pathway is frequently encountered in many malignancies including HBC and MPM and thus serves as an important target for therapeutic intervention strategies. Although proteasome inhibitor Velcade (Bortezomib) has been under clinical investigation for a number of cancers, limited preclinical studies with this agent have thus far been conducted in HBC and MPM malignancies. PURPOSE: To study the biological and molecular responses of MPM and HBC cells to Velcade treatments, and to identify mechanisms involved in transducing growth inhibitory effects of this agent. METHODS: Flow-cytometric analyses coupled with western immunoblotting and gene-array methodologies were utilized to determine mechanisms of Velcade-dependent growth suppression of five MPM (H2595, H2373, H2452, H2461, and H2714) and two breast cancer (MDA MB-468, SKBR-3) cell lines. RESULTS: Our data revealed significant reduction in cell growth properties that were dose and time dependent. Velcade treatment resulted in G2M phase arrest, increased expression of cyclin-dependent kinase inhibitor p21 and pro-apoptotic protein Bax. Pretreatment of mesothelioma cells with Velcade showed synergistic effect with cisplatin combination regimens. High-throughput gene expression profiling among Velcade treated and untreated mesothelioma cell lines resulted in identification of novel transducers of apoptosis such as CARP-1, XAF1, and Troy proteins. CONCLUSIONS: Velcade targets cell cycle and apoptosis signaling to suppress MPM and HBC growth in part by activating novel transducers of apoptosis. This pilot study has paved way for further in-depth analysis of the downstream target molecules associated with presensitization of mesothelioma cells in finding effective therapeutic treatment options for both mesothelioma and recalcitrant breast cancers

The human genome encodes several hundred microRNA (miRNA) genes that produce small (21-23n) single strand regulatory RNA molecules. Although abnormal expression of miRNAs has been linked to cancer progression, the mechanisms of this dysregulation are poorly understood. Malignant mesothelioma (MM) of pleura is an aggressive and highly lethal cancer resistant to conventional therapies. We and others previously linked loss of the 9p21.3 chromosome in MM with short time to tumor recurrence. In this study, we report that MM cell lines derived from patients with more aggressive disease fail to express miR-31, a microRNA recently linked with suppression of breast cancer metastases. We further demonstrate that this loss is due to homozygous deletion of the miR-31-encoding gene that resides in 9p21.3. Functional assessment of miR-31 activity revealed its ability to inhibit proliferation, migration, invasion, and clonogenicity of MM cells. Re-introduction of miR-31 suppressed the cell cycle and inhibited expression of multiple factors involved in cooperative maintenance of DNA replication and cell cycle progression, including pro-survival phosphatase PPP6C, which was previously associated with chemotherapy and radiation therapy resistance, and maintenance of chromosomal stability. PPP6C, whose mRNA is distinguished with three miR-31-binding sites in its 3'-untranslated region, was consistently down-regulated by miR-31 introduction and up-regulated in clinical MM specimens as compared with matched normal tissues. Taken together, our data suggest that tumor-suppressive propensity of miR-31 can be used for development of new therapies against mesothelioma and other cancers that show loss of the 9p21.3 chromosome

Asbestos carcinogenesis has been linked to the release of cytokines and mutagenic reactive oxygen species (ROS) from inflammatory cells. Asbestos is cytotoxic to human mesothelial cells (HM), which appears counterintuitive for a carcinogen. We show that asbestos-induced HM cell death is a regulated form of necrosis that links to carcinogenesis. Asbestos-exposed HM activate poly(ADP-ribose) polymerase, secrete H(2)O(2), deplete ATP, and translocate high-mobility group box 1 protein (HMGB1) from the nucleus to the cytoplasm, and into the extracellular space. The release of HMGB1 induces macrophages to secrete TNF-alpha, which protects HM from asbestos-induced cell death and triggers a chronic inflammatory response; both favor HM transformation. In both mice and hamsters injected with asbestos, HMGB1 was specifically detected in the nuclei, cytoplasm, and extracellular space of mesothelial and inflammatory cells around asbestos deposits. TNF-alpha was coexpressed in the same areas. HMGB1 levels in asbestos-exposed individuals were significantly higher than in nonexposed controls (P < 0.0001). Our findings identify the release of HMGB1 as a critical initial step in the pathogenesis of asbestos-related disease, and provide mechanistic links between asbestos-induced cell death, chronic inflammation, and carcinogenesis. Chemopreventive approaches aimed at inhibiting the chronic inflammatory response, and especially blocking HMGB1, may decrease the risk of malignant mesothelioma among asbestos-exposed cohorts

PURPOSE: Patients with early-stage, resectable, non-small-cell lung cancer (NSCLC) are at risk for recurrent disease, and 5-year survival rates do not exceed 75%. Angiogenesis inhibitors have shown clinical activity in patients with late-stage NSCLC, raising the possibility that targeting the vascular endothelial growth factor pathway in earlier-stage disease may be beneficial. This proof-of-concept study examined safety and efficacy of short-term, preoperative pazopanib monotherapy in patients with operable stage I/II NSCLC. PATIENTS AND METHODS: Patients scheduled for resection received oral pazopanib 800 mg/d for 2 to 6 weeks preoperatively. Tumor response was measured by high-resolution computed tomography, permitting estimation of change in tumor volume and diameter. Gene-expression profiling was performed on 77 pre- and post-treatment lung samples from 34 patients. RESULTS: Of 35 patients enrolled, 33 (94%) had clinical stage I NSCLC and two (6%) had clinical stage II NSCLC. Median treatment duration was 16 days (range, 3 to 29 days). Thirty patients (86%) achieved tumor-volume reduction after pazopanib treatment. Two patients achieved tumor-volume reduction > or = 50%, and three patients had partial response according to Response Evaluation Criteria in Solid Tumors. Pazopanib was generally well tolerated. The most common adverse events included grade 2 hypertension, diarrhea, and fatigue. One patient developed pulmonary embolism 11 days after surgery. Several pazopanib target genes and other angiogenic factors were dysregulated post-treatment. CONCLUSION: Short-duration pazopanib was generally well tolerated and demonstrated single-agent activity in patients with early-stage NSCLC. Several target genes were dysregulated after pazopanib treatment, validating target-specific response and indicating a persistent pazopanib effect on lung cancer tissue. Further clinical evaluation of pazopanib in NSCLC is planned

OBJECTIVE: Osteopontin is a multifunctional phosphoprotein with an important but poorly understood role in non-small cell lung cancer pathogenesis. We hypothesize that osteopontin isoforms (OPNa, OPNb, and OPNc) have divergent roles in non-small-cell lung cancer angiogenesis and divergent impact on vascular endothelial growth factor secretion. METHODS: We examined mRNA expression using reverse transcriptase-polymerase chain reaction primers for 3 osteopontin isoforms in non-small-cell lung cancer and immortalized bronchial epithelial cell lines, and correlated expression with osteopontin secretion into media detected by enzyme-linked immunosorbent assay. Angiogenic properties conferred by osteopontin isoforms were evaluated by transfecting cDNA plasmids specific to each isoform and controls into non-small-cell lung cancer cell lines, H153 and H358 (low endogenous osteopontin) and A549 and H460 (high endogenous osteopontin), analyzing conditioned media on a bovine capillary endothelial platform, and measuring vascular endothelial growth factor levels by enzyme-linked immunosorbent assay. RESULTS: OPNa mRNA expression correlated with osteopontin secretion in cell lines (r = 0.912, P = .0006). OPNa overexpression significantly increased tubule length compared with controls, OPNb had a similar, but less pronounced effect, and OPNc significantly decreased tubule length compared with controls in each cell line. OPNa overexpression was associated with significant increases in vascular endothelial growth factor secretion, whereas OPNb had no effect and OPNc overexpression was associated with significant decreases in vascular endothelial growth factor compared with controls in each cell line. CONCLUSION: We demonstrated divergent effects of osteopontin isoforms on non-small-cell lung cancer angiogenesis and vascular endothelial growth factor secretion. OPNa overexpression was associated with increased bovine capillary endothelial tubule length and vascular endothelial growth factor secretion, whereas OPNc was associated with decreases in both. These findings may lead to therapeutic strategies for selective isoform inhibition in non-small cell lung cancer