非小细胞肺癌免疫治疗的研究进展

肺癌(lung cancer)是全球发病率及死亡率最高的恶性肿瘤之一,非小细胞肺癌(non-small cell lung cancer,NSCLC)占肺癌的85%,其五年生存率只有15%,传统的抗肿瘤治疗方法(手术、放疗和化疗等)在抑制肿瘤进展中的作用有限,即使有手术机会,也有40%以上患者出现局部复发或远处转移。目前多学科治疗较大程度提高了晚期NSCLC的生存期,研究表明,免疫治疗(immunotherapy)可改善肺癌的预后,有望成为肺癌的重要辅助治疗方式。其中,治疗性肿瘤疫苗(vaccination)如MAGE-A3、L-BLP25、Belagenpum atucel-L等、免疫检查点抑制剂(immune checkpoint inhibition)如ipilimumab、nivolumab、pembrolizumab等得到广泛关注。一系列临床试验表明免疫治疗可以使非小细胞肺癌的死亡率得到缓解,本文就其原理、临床试验、不良反应及有待解决问题的临床研究作系统综述。     

Influence of non-specific immunologic factors on prognosis in advanced bronchogenic carcinoma

Summary Fifty-nine evaluable patients with stage III bronchogenic carcinoma, participating in a randomized clinical trial evaluating the effect of adjuvant immunotherapy with levamisole or BCG in the treatment of clinically advanced lung cancer, were studied for their immunocompetence by in vitro and in vivo assays. Immunological tests consisted of measurements of natural killer (NK) cell and killer (K) cell cytotoxicity, skin testing reactivity to recall antigens, absolute lymphocyte count, and serum immunoglobulin (Ig) levels. Pretherapy K cell cytotoxic levels, skin test reactivity to trichophyton antigen, and increased IgA levels were predictive of the overall clinical course. Despite non-specific immunotherapy, progressive decline of NK and K cell cytotoxicity occurred during the course of the disease. These findings, however, were of limited clinical value. Initial performance status and disease extent significantly influenced time to progression and survival. Little further prognostic information was obtained from the immunological tests over those provided by clinical performance status and disease extent. No statistically significant differences were found in either time to progression or survival between controls and patients receiving either levamisole or BCG.     

Clinical Perspectives to Overcome Acquired Resistance to Anti–Programmed Death-1 and Anti–Programmed Death Ligand-1 Therapy in Non-Small Cell Lung Cancer

Immune checkpoint inhibitors have changed the paradigm of treatment options for non-small cell lung cancer (NSCLC). Monoclonal antibodies targeting programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) have gained wide attention for their application, which has been shown to result in prolonged survival. Nevertheless, only a limited subset of patients show partial or complete response to PD-1 therapy, and patients who show a response eventually develop resistance to immunotherapy. This article aims to provide an overview of the mechanisms of acquired resistance to anti–PD-1/PD-L1 therapy from the perspective of tumor cells and the surrounding microenvironment. In addition, we address the potential therapeutic targets and ongoing clinical trials, focusing mainly on NSCLC.     

Screening for lung cancer.

The survival from bronchogenic carcinoma is highly dependent upon stage at the time of treatment. This is particularly true for squamous cell carcinoma, adenocarcinoma, and large cell carcinoma, but holds true for small cell carcinoma as well. The problem presented to the medical profession has been to find a practical means of detecting lung cancer while it is still at an early stage. Three studies in progress have indicated that a larger proportion of the patients may be found to have early stage lung cancer when screened with a combination of chest X-rays and sputum cytology. However, the detection of these early stage cases has not yet been translated into an improvement in the overall mortality rate from lung cancer.     

Immunotherapy for head and neck cancer

Head and neck cancer represents a challenging disease. Despite recent treatment advances, which have improved functional outcomes, the long-term survival of head and neck cancer patients has remained unchanged for the past 25 years. One of the goals of adjuvant cancer therapy is to eradicate local regional microscopic and micrometastatic disease with minimal toxicity to surrounding normal cells. In this respect, antigen-specific immunotherapy is an attractive therapeutic approach. With the advances in molecular genetics and fundamental immunology, antigen-specific immunotherapy is being actively explored using DNA, bacterial vector, viral vector, peptide, protein, dendritic cell, and tumor-cell based vaccines. Early phase clinical trials have demonstrated the safety and feasibility of these novel therapies and the emphasis is now shifting towards the development of strategies, which can increase the potency of these vaccines. As the field of immunotherapy matures and as our understanding of the complex interaction between tumor and host develops, we get closer to realizing the potential of immunotherapy as an adjunctive method to control head and neck cancer and improve long-term survival in this patient population.     

EMT: A mechanism for escape from EGFR-targeted therapy in lung cancer

Epithelial mesenchymal transition (EMT) is a reversible developmental genetic programme of transdifferentiation of polarised epithelial cells to mesenchymal cells. In cancer, EMT is an important factor of tumour cell plasticity and has received increasing attention for its role in the resistance to conventional and targeted therapies. In this paper we provide an overview of EMT in human malignancies, and discuss contribution of EMT to the development of the resistance to Epidermal Growth Factor Receptor (EGFR)-targeted therapies in non-small cell lung cancer (NSCLC). Patients with the tumours bearing specific mutations in EGFR have a good clinical response to selective EGFR inhibitors, but the resistance inevitably develops. Several mechanisms responsible for the resistance include secondary mutations in the EGFR gene, genetic or non-mutational activation of alternative survival pathways, transdifferentiation of NSCLC to the small cell lung cancer histotype, or formation of resistant tumours with mesenchymal characteristics. Mechanistically, application of an EGFR inhibitor does not kill all cancer cells; some cells survive the exposure to a drug, and undergo genetic evolution towards resistance. Here, we present a theory that these quiescent or slow-proliferating drug-tolerant cell populations, or so-called “persisters”, are generated via EMT pathways. We review the EMT-activated mechanisms of cell survival in NSCLC, which include activation of ABC transporters and EMT-associated receptor tyrosine kinase AXL, immune evasion, and epigenetic reprogramming. We propose that therapeutic inhibition of these pathways would eliminate pools of persister cells and prevent or delay cancer recurrence when applied in combination with the agents targeting EGFR.     

Cancer immunotherapy.

Important contributions that stimulated studies in cancer immunotherapy included: (1) the discovery of tumour-associated antigens; (2) the observation that infection with bacille Calmette-Guérin (BCG) in animals was protective against tumour challenge; and (3) the observation that immunodepression due either to malignant disease or to treatment of the disease, was, in some instances, related to prognosis. Immunotherapy trials with microbial agents have involved attempts to obtain a local effect by injecting the agent into the tumour or into the region of the tumour and to obtain a "systemic" effect distant from the site of injection. Trials with active specific immunotherapy involving tumour cells or tumour cell extracts have frequently involved the combination of these specific agents with a nonspecific adjuvant such as BCG. Recent studies with thymosin and levamisole in patients with lung cancer and other types of malignant disease have shown prolonged survival in the groups receiving immunotherapy.     

Recent Development of the Second and Third Generation Irreversible Epidermal Growth Factor Receptor Inhibitors

Recent reports suggested that essential directions for new lung cancer, breast carcinoma therapies, as well as the roomier realm of targeted cancer therapies were provided through targeting the epidermal growth factor receptor (EGFR). Patients who carrying non‐small cell lung carcinoma (NSCLC) with activating mutations in EGFR initially respond well to the EGFR inhibitors erlotinib and gefitinib, which were located the active site of the EGFR kinase and designed to act as competitive inhibitors of combining with the ATP. However, patients who were treated with the erlotinib and gefitinib will relapse because of the emergence of drug‐resistant mutations, with T790M mutations accounting for approximately 60% of all resistance. In order to overcome drug resistance, Pharmaceutical chemistry experts recently devoted great endeavors to the development of second‐generation irreversible selective inhibitors which covalently modify Cys797 or Cys773 at the ATP binding cleft. Nevertheless, these inhibitors have not reached ideal effect of experts in patients with T790M positive mutation and apparently because of the dose‐limiting toxicities associated with inhibition of wild type EGFR. A novel class of ‘third generation’ EGFR TKIs have been developed that is sensitising and T790M mutant‐specific whilst sparing WT EGFR, representing a significant breakthrough in the treatment in NSCLC patients with acquired resistance harboring these genotypes. Herein, we provides an overview of the second and third generation inhibitors currently approved, in clinical trial and also encompasses novel structures of discovery. This review mainly focuses on drug resistance, their mechanisms of action, development of structure–activity relationships and binding modes.     

A phase-II trial of Corynebacterium parvum as adjuvant to surgery in the treatment of operable lung cancer

A phase-II randomized trial has been undertaken in 49 patients with operable lung cancer, to determine the effect of a single IV infusion of killed C. parvum vaccine as an adjuvant to surgery. The number of patients was insufficient to provide a decisive result, but analysis 6 years after the last patient was admitted shows that the adjuvant therapy certainly did not shorten, and may well have prolonged, survival. Of the patients with squamous cell carcinoma who were alive 1 year after operation all except one in the C. parvum-treated group were alive 4 years later, whereas five in the control group died during this interval. Judgement concerning the value of IV administration of CP as adjuvant therapy in patients with operable lung cancer should be deferred until further evidence is available.     

Cancer immunotherapy: recent breakthroughs and perspectives

Immunotherapy of cancer has long been considered as an attractive therapeutic approach but with no impact on clinical practice. Two clinical protocols of immunotherapy, one based on a cancer vaccine in patients with prostate cancer or melanoma and the other using an immunomodulator targeting T cells (anti-CTLA4 mAb) in melanoma patients, have demonstrated clinical efficacy in two phase?III clinical trials. To improve these encouraging clinical results, biomarkers to better select patients which may benefit from this therapy are actively searched. In addition, immunosuppression associated with cancer has to be overcome to allow a better immunostimulation. In contrast to chemotherapy, clinical variables to monitor the efficacy of immunotherapy has to be revisited and overall survival appears to be a better endpoint than clinical response defined by the RECIST criteria. Combination of immunotherapy with conventional treatments (chemotherapy, anti-angiogenic, etc.) should further improve this approach both in its effectiveness and in its clinical indications.     

Dendritic cells efficiently acquire and present antigen derived from lung cancer cells and induce antigen-specific T-cell responses

Active immunotherapy of cancer requires the availability of a source of tumor antigens. To date, no such antigen associated with lung cancer has been identified. We have therefore investigated the ability of dendritic cells (DC) to capture whole irradiated human lung tumor cells and to present a defined surrogate antigen derived from the ingested tumor cells. We also describe an in vitro system using a modified human adenocarcinoma cell line (A549-M1) that expresses the well-characterized, immunogenic influenza M1 matrix protein as a surrogate tumor antigen. Peripheral blood monocyte-derived DC, when co-cultured with sub-lethally irradiated A549 cells or primary lung tumor cells derived from surgical resection of non-small cell carcinoma (NSCLC), efficiently ingested the tumor cells as determined by flow cytometry analysis and confocal microscopic examination. More importantly, DC loaded with irradiated A549-M1 cells efficiently processed and presented tumor cell-derived M1 antigen to T cells and elicited antigen-specific immune responses that included IFNgamma release from an M1-specific T-cell line, expansion of M1 peptide-specific Vbeta17+ and CD8+ peripheral T cells and generation of M1-specific cytotoxic T lymphocytes (CTL). We also compared DC loaded with irradiated tumor cells to those loaded with tumor cell lysate or killed tumor cells and found that irradiated lung tumor cells as a source of tumor antigen for DC loading is superior to tumor cell lysate or killed tumor cells in efficient induction of antigen-specific T-cell responses. Our results demonstrate the feasibility of using lung tumor cell-loaded DC to induce immune responses against lung cancer-associated antigens and support ongoing efforts to develop a DC-based lung cancer vaccine.     

McAb LC-1 against human lung cancer

Recently Ge et al reported LAC-122, LAC-210 and LAC-163 McAbs against Human non-small cell lung cancer and LSC McAbs against human lung small cell carcinoma. The immunotoxin, composed of McAb LAC-122 conjugated with Ricin A chain has been reported to have the significant cytotoxic effect in vitro on lung adenocarcinoma cell line SPC-A-1 by Tan et al. The LAC-122 alone has no effect on this target cell in the presence of complement from human, rabbit or guinea pig. The tumor associated antigens of human lung cancer have been recognized for many years, but only few reports deal with the common antigens or common epitopes of the lung cancer. From one fusion, 20 hybrids had been observed, all of these culture supernatants could react with target cell by IF. One of them after 4 th cloning, immunoglobulin isotype of the monoclonal antibody thus far obtained belonged to IgM and named to LC-1. Table 1 showed the results of ABC staining of LC-1 with a variety of tumors, normal adult and fetal tissues. From 12 non-small cell lung cancers, including 7 lung adenocarcinoma, 2 lung squamous carcinoma, 3 lung giant cell carcinoma, only one adenocarcinoma gave negative staining. As for 6 small cell lung cancers, all of them showed the positive reaction. It could be also reacted with 11 other tumors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Superficial bladder cancer therapy

Bladder cancer treatment remains a challenge despite significant improvements in preventing disease progression and improving survival. Intravesical therapy has been used in the management of superficial transitional cell carcinoma (TCC) of the urinary bladder (i.e. Ta, T1, and carcinoma in situ) with specific objectives which include treating existing or residual tumor, preventing recurrence of tumor, preventing disease progression, and prolonging survival. The initial clinical stage and grade remain the main determinant factors in survival regardless of the treatment. Prostatic urethral mucosal involvement with bladder cancer can be effectively treated with Bacillus Calmette-Guerin (BCG) intravesical immunotherapy. Intravesical chemotherapy reduces short-term tumor recurrence by about 20%, and long-term recurrence by about 7%, but has not reduced progression or mortality. Presently, BCG immunotherapy remains the most effective treatment and prophylaxis for TCC (Ta, T1, CIS) and reduces tumor recurrence, disease progression, and mortality. Interferons, Keyhole-limpet hemocyanin (KLH), bropirimine and Photofrin-Photodynamic Therapy (PDT) are under investigation in the management of TCC and early results are encouraging. This review highlights and summarizes the recent advances in therapy for superficial TCC.     

Immunohystochemical expression of cancer/testis antigens (MAGE-A3/4, NY-ESO-1) in non-small cell lung cancer: the relationship with clinical-pathological features

The aim of this study was to explore the expression of cancer/testis tumor associated antigens (C/T TAAs) MAGE-A 3/4 and NY-ESO-1 in lung squamous cell carcinoma and adenocarcinoma, and to evaluate their association with the standard clinical-pathological features of surgically treated lung cancer patients. The study included 80 patients with non-small cell lung cancer (40 adenocarcinomas, 40 squamous cell carcinomas) who had undergone surgery in the period between 2002 and 2005. The MAGE-A3/4 and NY-ESO-1 antigen expression was analyzed immunohistochemically (IHC). The results showed MAGE-A3/4 and NY-ESO-1 positive staining in 65.1% and 23.3% of squamous cell carcinomas and 18.9% and 10.8% of adenocarcinomas, respectively. A statistically higher MAGE-A3/4 expression was observed in planocellular bronchial carcinoma (p < 0.001), while no difference was found in the expression of NY-ESO-1 in adenocarcinoma and planocellular carcinoma (p = 0.144). A significant association was found between the MAGE-A3/4 expression and presence of tumor necrosis in squamous cell cancer specimens (p = 0.001), but not in adenocarcinoma (p = 0.033). A statistically significant association was noted between the NY-ESO-1 expression and positive hilar and mediastinal lymph nodes in adenocarcinoma (p = 0.025) whereas it was not the case in squamous cell carcinoma. Non-small cell lung cancer frequently expresses cancer/testis tumor associated antigens. Our results demonstrate that the MAGE-A3/4 and NY-ESO-1 expression was significant associated with prognostic factors of poor outcome of disease (presence of tumor necrosis and lymph node metastasis). As C/T antigens are important for inducing a specific immune reaction in lung cancer patients, there is an intention to form a subgroup of patients in the future, whose treatment would be enhanced by specific immunotherapy based on the observed scientific results.     

Updates in Gastrointestinal Oncology – insights from the 2008 44th annual meeting of the American Society of Clinical Oncology

Tyrosine Kinase Inhibitors (TKI) have significantly changed the landscape of current cancer therapy. Understanding of mechanisms of aberrant TK signaling and strategies to inhibit TKs in cancer, further promote the development of novel agents. ABT-869, a novel ATP-competitive receptor tyrosine kinase inhibitor is a potent inhibitor of members of the vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF) receptor families. ABT-869 showed potent antiproliferative and apoptotic properties in vitro and in animal cancer xenograft models using tumor cell lines that were "addicted" to signaling of kinases targeted by ABT-869. When given together with chemotherapy or mTOR inhibitors, ABT-869 showed at least additive therapeutic effects. The phase I trial for ABT-869 was recently completed and it demonstrated respectable efficacy in solid tumors including lung and hepatocellular carcinoma with manageable side effects. Tumor cavitation and reduction of contrast enhancement after ABT-869 treatment supported the antiangiogenic activity. The correlative laboratory studies conducted with the trial also highlight potential biomarkers for future patient selection and treatment outcome. Parallel to the clinical development, in vitro studies on ABT-869 resistance phenotype identified novel resistance mechanism that may be applicable to other TKIs. The future therapeutic roles of ABT-869 are currently been tested in phase II trials.     

In vitro mimicry of CaMBr1 tumor-associated antigen by synthetic oligosaccharides

The murine monoclonal antibody (Mab) MBr1, raised against thebreast cancer cell line MCF7, recognizes a saccharidic epitopeoverexpressed on a high percentage of human breast, ovary, andlung carcinomas. This antigen was originally identified on theimmunogen as a globo-series glycosphingolipid with an H-likedeterminant at its terminus (globo-H). We report here the biologicalcharacterization of the entire globo-H hexasaccharide and fivesynthetic oligosaccharides representing fragments of the entirestructure andlor different anomeric configurations. Using competitivebinding assays on live cells, we identified the residues andthe linkages essential for mimicry of the cellular antigensrecognized by Mab MBr1 on the breast carcinoma cell line MCF7and small cell lung cancer cell line POVD. The terminal tetrasaccharidicfragment of globo-H is the oligosaccharide that most resemblesthe MBr1-defined epitope both on glycolipids and on glycoproteins.This information will help in the rational design of a highlyspecific reagent for active specific immunotherapy of carcinomasoverexpressing the MBr1-defined antigen. CaMBr1 immunotherapy monoclonal antibody oligosaccharides tumor-associated antigen     

Association of glutathione S-transferase P1 gene polymorphism with the histological types of lung cancer: a meta-analysis

The conclusions of the published reports on the relationship between glutathione S-transferase P1 (GSTP1) A/G gene polymorphism and the histological types of lung cancer are still debated. GSTP1 is one of the important mutant sites reported at present. This meta-analysis was performed to evaluate the association between GSTP1 and histological types of lung cancer. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Seventeen reports were included into this meta-analysis for the association of GSTP1 A/G gene polymorphism and histological types of lung cancer. The G allele and GG genotype were not associated with the susceptibility of risk of squamous cell carcinomas, adenocarcinomas, small cell carcinoma, non-small cell carcinoma or large cell carcinoma. However, in the sub-group analysis, there was an association between G allele/GG genotype with the risk of squamous cell carcinomas in East-Asians and GG genotype was associated with the risk of small cell carcinoma in Caucasians. In conclusion, GSTP1 A/G gene polymorphism is not associated with the susceptibility of squamous cell carcinomas, adenocarcinomas, small cell carcinoma, non-small cell carcinoma or large cell carcinoma.     

Anti-PD1 therapy induces lymphocyte-derived exosomal miRNA-4315 release inhibiting Bim-mediated apoptosis of tumor cells

Anti-PD1 immunotherapy, as a single agent or in combination with standard chemotherapies, has significantly improved the outcome of many patients with cancers. However, resistance to anti-PD1 antibodies often decreases the long-term therapeutic benefits. Despite this observation in clinical practice, the molecular mechanisms associated with resistance to anti-PD1 antibody therapy have not yet been elucidated. To identify the mechanisms of resistance associated with anti-PD1 antibody therapy, we developed cellular models including purified T cells and different cancer cell lines from glioblastoma, lung adenocarcinoma, breast cancer and ovarian carcinoma. A murine model of lung cancer was also used. Longitudinal blood samples of patients treated with anti-PD1 therapy were also used to perform a proof-of-concept study of our findings. We found that anti-PD1 exposure of T-cell promotes an enrichment of exosomal miRNA-4315. We also noted that exosomal miRNA-4315 induced a phenomenon of apopto-resistance to conventional chemotherapies in cancer cells receiving exosomal miRNA-4315. At molecular level, we discern that the apopto-resistance phenomenon was associated with the miRNA-4315-mediated downregulation of Bim, a proapoptotic protein. In cellular and mice models, we observed that the BH3 mimetic agent ABT263 circumvented this resistance. A longitudinal study using patient blood showed that miRNA-4315 and cytochrome c can be used to define the time period during which the addition of ABT263 therapy may effectively increase cancer cell death and bypass anti-PD1 resistance.This work provides a blood biomarker (exosomal miRNA-4315) for patient stratification developing a phenomenon of resistance to anti-PD1 antibody therapy and also identifies a therapeutic alternative (the use of a BH3 mimetic drug) to limit this resistance phenomenon.Subject terms: Cancer, miRNAs     

A phase-II trial of Corynebacterium parvum as adjuvant to surgery in the treatment of operable lung cancer

Summary A phase-II randomized trial has been undertaken in 49 patients with operable lung cancer, to determine the effect of a single IV infusion of killed C. parvum vaccine as an adjuvant to surgery. The number of patients was insufficient to provide a decisive result, but analysis 6 years after the last patient was admitted shows that the adjuvant therapy certainly did not shorten, and may well have prolonged, survival. Of the patients with squamous cell carcinoma who were alive 1 year after operation all except one in the C. parvum-treated group were alive 4 years later, whereas five in the control group died during this interval.Judgement concerning the value of IV administration of CP as adjuvant therapy in patients with operable lung cancer should be deferred until further evidence is available.Emeritus Professor of Surgery, University of EdinburghConsultant Cardio-Thoracic Surgeon