Mariacarmela Santarpia

Treatment of non-small-cell lung cancer and pharmacogenomics: where we are and where we are going.

Purpose of review This review highlights the numerous molecular biology findings in the field of lung cancer with potential therapeutic impact in both the near and distant future. Recent findings Abundant preclinical and clinical data indicate that BRCA1 mRNA expression is a differential modulator of chemotherapy sensitivity. Single nucleotide polymorphisms in the excision repair cross-complementing 1 gene (ERCC1) influence survival with cisplatin-based chemotherapy. For the first time, epidermal growth factor receptor (EGFR) mutations have been shown to predict dramatic responses in metastatic lung adenocarcinomas. The crosstalk between estrogen and EGFR pathways have also been revealed. MicroRNAs control the expression of cognate target genes and predict relapse in surgically resected non-small-cell lung cancer patients. Overexpression of the Wingless-type (Wnt) genes and methylation of Wnt antagonists have been documented in non-small-cell lung cancer. Summary Understanding the relevance of these findings can help to change the clinical practice in oncology towards customizing chemotherapy and targeted therapies, leading to improvement both in survival and in cost-effectiveness.

mRNA expression levels and genetic status of genes involved in the EGFR and NF-κB pathways in metastatic non-small-cell lung cancer patients

BackgroundMetastatic non-small-cell lung cancer (NSCLC) has a dismal prognosis. EGFR is overexpressed or mutated in a large proportion of cases. Downstream components of the EGFR pathway and crosstalk with the NF-κB pathway have not been examined at the clinical level. We explored the prognostic significance of the mRNA expression of nine genes in the EGFR and NF-κB pathways and of BRCA1 and RAP80 in patients in whom EGFR and K-ras gene status had previously been determined. In addition, NFKBIA and DUSP22 gene status was also determined.MethodsmRNA expression of the eleven genes was determined by QPCR in 60 metastatic NSCLC patients and in nine lung cancer cell lines. Exon 3 of NFKBIA and exon 6 of DUSP22 were analyzed by direct sequencing. Results were correlated with outcome to platinum-based chemotherapy in patients with wild-type EGFR and to erlotinib in those with EGFR mutations.ResultsBRCA1 mRNA expression was correlated with EZH2, AEG-1, Musashi-2, CYLD and TRAF6 expression. In patients with low levels of both BRCA1 and AEG-1, PFS was 13.02 months, compared to 5.4 months in those with high levels of both genes and 7.7 months for those with other combinations (P = 0.025). The multivariate analysis for PFS confirmed the prognostic role of high BRCA1/AEG-1 expression (HR, 3.1; P = 0.01). Neither NFKBIA nor DUSP22 mutations were found in any of the tumour samples or cell lines.ConclusionsThe present study provides a better understanding of the behaviour of metastatic NSCLC and identifies the combination of BRCA1 and AEG-1 expression as a potential prognostic model.

Emerging drugs for non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) accounts for 80% of all lung cancer cases and is the leading cause of cancer mortality. Despite the optimization of chemotherapy regimens, treatment outcomes for advanced disease are still disappointing. The EGFR tyrosine kinase inhibitor, erlotinib, and the recombinant monoclonal antibody against the VEGF, bevacizumab, have proven active in NSCLC. In the BR.21 trial, a 2-month benefit in overall survival was observed for previously treated NSCLC patients who received erlotinib versus placebo. The combination of chemotherapy plus bevacizumab yielded superior overall survival or progression-free survival in one randomized trial in advanced non-squamous NSCLC patients. However, despite the introduction of more effective agents, new treatment strategies are clearly needed in lung cancer management. The review focuses on a number of new targeted agents/chemotherapy drugs now in clinical trials directed at improving NSCLC management. Mature results regarding their activity and usefulness can be expected in the near future.

Tyrosine kinase inhibitors for non-small-cell lung cancer: finding patients who will be responsive

In recent years, the management of lung cancer has been moving towards molecular-guided treatment, and the best example of this new approach is the use of the tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib in patients with mutations in the epidermal growth factor receptor (EGFR). Erlotinib was introduced as a second- and third-line therapy for advanced non-small-cell lung cancer and demonstrated a survival advantage over placebo in unselected patients. Gefitinb did not confer the same advantage but specific subgroups of patients obtained higher response rates. The discovery of EGFR mutations explained the molecular mechanism of sensitivity to TKIs, and several clinical trials have evaluated the efficacy of TKIs in EGFR-mutated patients. New molecular alterations involving different genes have also been described and associated with sensitivity or resistance to TKIs. The identification of molecular predictors of response can allow the selection of patients who will be the most likely to respond to erlotinib and gefitinib.

Tumor immune microenvironment characterization and response to anti-PD-1 therapy

In recent years, further understanding of the interaction between the immune system and tumor growth has led to the development of several immunotherapies. These immunotherapies include cancer vaccines and immune checkpoint inhibitors that have been tested in various solid tumors, including those traditionally considered non-immunogenic, such as non-small cell lung cancer (NSCLC). In physiological state, T-cell-mediated immune response against foreign antigens is regulated by stimulatory and inhibitory signals, which are critical to prevent autoimmunity and protect normal tissues after immune system activation. Cancer cells harbor different genetic and epigenetic alterations; thus, neoantigens that are potentially recognized and eliminated by the immune system are expressed. Adaptive immune responses, particularly IFN-γ-secreting T cells, exert a core function in tumor immune surveillance. However, tumors can escape this surveillance and maintain an immunosuppressive microenvironment through multiple mechanisms, including recruitment of regulatory cells (e.g., regulatory T cells, myeloid-derived suppression cells, and type 2 macrophages) and production of molecules suppressing antitumor T-cell responses (e.g., interleukin-10 and transforming growth factor-β). Tumor growth is also associated with immunomodulation of T-cell response through enhancement of co-inhibitory molecules or immune checkpoints, such as cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) or programmed cell death-1 (PD-1), on T cells1,2. Immunotherapies may affect various tumors by activating adaptive immune system response, including blockade of immune checkpoint pathways.

Programmed cell death protein-1/programmed cell death ligand-1 pathway inhibition and predictive biomarkers: understanding transforming growth factor-beta role

A deeper understanding of the key role of the immune system in regulating tumor growth and progression has led to the development of a number of immunotherapies, including cancer vaccines and immune checkpoint inhibitors. Immune checkpoint inhibitors target molecular pathways involved in immunosuppression, such as cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathway, with the goal to enhance the hosts own immune anticancer response. In phase I-III trials, anti-PD-1/PD-L1 antibodies have demonstrated to be effective treatment strategies by inducing significant durable tumor responses, with manageable toxicities, in patients with various malignancies, including those traditionally considered non-immunogenic, such as non-small cell lung cancer (NSCLC). Identification of predictive biomarkers to select patients for immune therapies is currently being investigated to improve their therapeutic efficacy. Transforming growth factor-β (TGF-β), a pleiotropic cytokine with immunosuppressive effects on multiple cell types of the innate and adaptive immune system, has emerged as one of the potential key factors modulating response to immune checkpoint inhibitors. However, due to the complexity of the anti-cancer immune response, the predictive value of many other factors related to cancer cells or tumor microenvironment needs to be further explored.

Strategies to overcome resistance to tyrosine kinase inhibitors in non-small-cell lung cancer

The use of molecularly targeted agents has dramatically improved the prognosis of defined subsets of patients with non-small-cell lung cancer harboring somatically activated oncogenes, such as mutant EGFR or rearranged ALK. However, after initial marked responses to EGFR or ALK tyrosine kinase inhibitors (TKIs), almost all patients inevitably progress due to development of acquired resistance. Multiple molecular mechanisms of resistance have been identified; the best characterized are secondary mutations in the tyrosine kinase domain of the oncogene, such as T790M in EGFR and L1196M in ALK, which prevent target inhibition by the corresponding TKI. Other mechanisms include copy number gain of the ALK fusion gene and the activation of bypass signaling pathways that can maintain downstream proliferation and survival signals despite inhibition of the original drug target. Here, the authors provide an overview of the known mechanisms of resistance to TKIs and outline the therapeutic strategies, including new investigational agents and targeted therapies combinations, that have been developed to overcome resistance.

Targeted drugs in small-cell lung cancer

In contrast to non-small-cell lung cancer (NSCLC), few advances have been made in systemic treatment of small-cell lung cancer (SCLC) in recent years. Most patients are diagnosed with extensive stage disease and are commonly treated with platinum-based chemotherapy which, although attaining high initial objective responses, has a limited impact on survival. Due to the dismal prognosis of SCLC, novel and more effective treatment strategies are urgently needed. A deeper characterization of the genomic landscape of SCLC has led to the development of rational and promising targeted agents. However, despite a large number of clinical trials, results have been disappointing and there are still no approved targeted drugs for SCLC. Recent comprehensive genomic studies suggest SCLC is a heterogeneous disease, characterized by genomic alterations targeting a broad variety of genes, including those involved in transcription regulation and chromatin modification which seem to be a hallmark of this specific lung cancer subtype. Current research efforts are focusing on further understanding of the cellular and molecular abnormalities underlying SCLC development, progression and resistance to chemotherapy. Unraveling the genomic complexity of SCLC could be the key to optimize existing treatments, including chemotherapy and radiotherapy, and for identifying those patients most likely to benefit from selected targeted therapeutic approaches.

BIM and mTOR expression levels predict outcome to erlotinib in EGFR-mutant non-small-cell lung cancer

BIM is a proapoptotic protein that initiates apoptosis triggered by EGFR tyrosine kinase inhibitors (TKI). mTOR negatively regulates apoptosis and may influence response to EGFR TKI. We examined mRNA expression of BIM and MTOR in 57 patients with EGFR-mutant NSCLC from the EURTAC trial. Risk of mortality and disease progression was lower in patients with high BIM compared with low/intermediate BIM mRNA levels. Analysis of MTOR further divided patients with high BIM expression into two groups, with those having both high BIM and MTOR experiencing shorter overall and progression-free survival to erlotinib. Validation of our results was performed in an independent cohort of 19 patients with EGFR-mutant NSCLC treated with EGFR TKIs. In EGFR-mutant lung adenocarcinoma cell lines with high BIM expression, concomitant high mTOR expression increased IC50 of gefitinib for cell proliferation. We next sought to analyse the signalling pattern in cell lines with strong activation of mTOR and its substrate P-S6. We showed that mTOR and phosphodiesterase 4D (PDE4D) strongly correlate in resistant EGFR-mutant cancer cell lines. These data suggest that the combination of EGFR TKI with mTOR or PDE4 inhibitors could be adequate therapy for EGFR-mutant NSCLC patients with high pretreatment levels of BIM and mTOR.

Advances in immunotherapy for treatment of lung cancer.

Different approaches for treating lung cancer have been developed over time, including chemotherapy, radiotherapy and targeted therapies against activating mutations. Lately, better understanding of the role of the immunological system in tumor control has opened multiple doors to implement different strategies to enhance immune response against cancer cells. It is known that tumor cells elude immune response by several mechanisms. The development of monoclonal antibodies against the checkpoint inhibitor programmed cell death protein 1 (PD-1) and its ligand (PD-L1), on T cells, has led to high activity in cancer patients with long lasting responses. Nivolumab, an anti PD-1 inhibitor, has been recently approved for the treatment of squamous cell lung cancer patients, given the survival advantage demonstrated in a phase III trial. Pembrolizumab, another anti PD-1 antibody, has received FDA breakthrough therapy designation for treatment of non-small cell lung cancer (NSCLC), supported by data from a phase I trial. Clinical trials with anti PD-1/PD-L1 antibodies in NSCLC have demonstrated very good tolerability and activity, with response rates around 20% and a median duration of response of 18 months.