Highly potent mRNA based cancer vaccines represent an attractive platform for combination therapies supporting an improved therapeutic effect

Direct vaccination with mRNA encoding tumor antigens is a novel and promising approach in cancer immunotherapy. CureVac's mRNA vaccines contain free and protamine-complexed mRNA. Such two-component mRNA vaccines support both antigen expression and immune stimulation. These self-adjuvanting RNA vaccines, administered intradermally without any additional adjuvant, induce a comprehensive balanced immune response, comprising antigen specific CD4+ T cells, CD8+ T cells and B cells. The balanced immune response results in a strong anti-tumor effect and complete protection against antigen positive tumor cells. This tumor inhibition elicited by mRNA vaccines is a result of the concerted action of different players. After just two intradermal vaccinations, we observe multiple changes at the tumor site, including the up-regulation of many genes connected to T and natural killer cell activation, as well as genes responsible for improved infiltration of immune cells into the tumor via chemotaxis. The two-component mRNA vaccines induce a very fast and boostable immune response. Therefore, the vaccination schedules can be adjusted to suit the clinical situation. Moreover, by combining the mRNA vaccines with therapies in clinical use (chemotherapy or anti-CTLA-4 antibody therapy), an even more effective anti-tumor response can be elicited. The first clinical data obtained from two separate Phase I/IIa trials conducted in PCA (prostate cancer) and NSCLC (non-small cell lung carcinoma) patients have shown that the two-component mRNA vaccines are safe, well tolerated and highly immunogenic in humans.

Cancer vaccines: should we be targeting patients with less aggressive disease?

There is enthusiasm for using vaccines to stimulate the immune system to treat cancer. In this article, the authors review the evolution of vaccines evaluated in clinical trials, starting with Phase III trials in metastatic disease and progressing to trials in the adjuvant setting. Data from these trials suggest that cancer vaccines may be more effective in patients with lower volume disease, and data from the E75 peptide vaccine trials suggest that vaccines may be most effective in less aggressive disease.

Identification of novel MAGE-A6- and MAGE-A12-derived HLA-A24-restricted cytotoxic T lymphocyte epitopes using an in silico peptide-docking assay

Many cancer-testis antigen genes have been identified; however, few human leukocyte antigen (HLA)-A24-restricted cytotoxic T cell (CTL) epitope peptides are available for clinical immunotherapy. To solve this problem, novel tools increasing the efficacy and accuracy of CTL epitope detection are needed. In the present study, we utilized a highly active dendritic cell (DC)-culture method and an in silico HLA-A24 peptide-docking simulation assay to identify novel CTL epitopes from MAGE-A6 and MAGE-A12 antigens. The highly active DCs, called α-type-1 DCs, were prepared using a combination of maturation reagents to produce a large amount of interleukin-12. Meanwhile, our HLA-A24 peptide-docking simulation assay was previously demonstrated to have an obvious advantage of accuracy over the conventional prediction tool, bioinformatics and molecular analysis section. For CTL induction assays, peripheral blood mononuclear cells derived from six cases of HLA-A24(+) melanoma were used. Through CTL induction against melanoma cell lines and peptide-docking simulation assays, two peptides (IFGDPKKLL from MAGE-A6 and IFSKASEYL from MAGE-A12) were identified as novel CTL epitope candidates. Finally, we verified that the combination of the highly active DC-culture method and HLA-A24 peptide-docking simulation assay might be tools for predicting CTL epitopes against cancer antigens.

Proteomic profiling of triple-negative breast carcinomas in combination with a three-tier orthogonal technology approach identifies Mage-A4 as potential therapeutic target in estrogen receptor negative breast cancer

Breast cancer is a very heterogeneous disease, encompassing several intrinsic subtypes with various morphological and molecular features, natural history and response to therapy. Currently, molecular targeted therapies are available for estrogen receptor (ER)(-) and human epidermal growth factor receptor 2 (Her2)-positive breast tumors. However, a significant proportion of primary breast cancers are negative for ER, progesterone receptor (PgR), and Her2, comprising the triple negative breast cancer (TNBC) group. Women with TNBC have a poor prognosis because of the aggressive nature of these tumors and current lack of suitable targeted therapies. As a consequence, the identification of novel relevant protein targets for this group of patients is of great importance. Using a systematic two dimensional (2D) gel-based proteomic profiling strategy, applied to the analysis of fresh TNBC tissue biopsies, in combination with a three-tier orthogonal technology (two dimensional PAGE/silver staining coupled with MS, two dimensional Western blotting, and immunohistochemistry) approach, we aimed to identify targetable protein markers that were present in a significant fraction of samples and that could define therapy-amenable sub-groups of TNBCs. We present here our results, including a large cumulative database of proteins based on the analysis of 78 TNBCs, and the identification and validation of one specific protein, Mage-A4, which was expressed in a significant fraction of TNBC and Her2-positive/ER negative lesions. The high level expression of Mage-A4 in the tumors studied allowed the detection of the protein in the tumor interstitial fluids as well as in sera. The existence of immunotherapeutics approaches specifically targeting this protein, or Mage-A protein family members, and the fact that we were able to detect its presence in serum suggest novel management options for TNBC and human epidermal growth factor receptor 2 positive/estrogen receptor negative patients bearing Mage-A4 positive tumors.

Clinical significance of human leukocyte antigen loss and melanoma-associated antigen 4 expression in smokers of non-small cell lung cancer patients

BACKGROUND

Melanoma-associated antigen-A4 (MAGE-A4) is one of the candidates for a target of immunotherapy and is expressed in non-small cell lung cancer (NSCLC). However, tumors sometimes lose human leukocyte antigen (HLA) class I expression, and tumor-specific T cells cannot eliminate the tumor with loss of HLA. However, the relationship between MAGE-A4 expression and HLA loss has remained unclear.

METHODS

Among 363 NSCLC patients who consecutively underwent curative surgery, 187 cases whose material could be analyzed were reviewed. The expression of HLA class I molecules was assessed by immunohistochemical staining. The expression of MAGE-A4 was analyzed by RT-PCR.

RESULTS

Seventy-seven tumors expressed HLA normally; however, 110 tumors lost HLA. The proportion of patients with a smoking habit and expressing the MAGE-A4 gene in patients with HLA loss was higher than those with HLA expression (p = 0.04 and 0.028, respectively). Five-year overall survival (OS) rate in the patients expressing MAGE-A4 but with loss of HLA was 52.4 %, and OS was significantly poorer than their counterparts (74.0 %, p = 0.036). Multivariate analysis indicated that advanced stage or history of smoking and HLA loss was an independently poor prognostic predictor of OS in NSCLC (p < 0.01 and p = 0.04, respectively).

CONCLUSION

HLA class I loss in NSCLC was related to smoking history and MAGE-A4 expression of tumors. HLA class I loss in smokers or patients with the MAGE-A4 gene was a prognostic factors in NSCLC.

Therapeutic cancer vaccines: the latest advancement in targeted therapy

Therapeutic cancer vaccines represent an emerging therapeutic modality that may play a more prominent role in cancer treatment in the future. Therapeutic cancer vaccines are designed to generate a targeted, immune-mediated antitumor response. There are 2 main types of therapeutic vaccines: patient-specific (generated either from a patient's own cells or tumor) and patient- nonspecific, where a peptide- or vector-based vaccine induces an immune response in vivo against specific tumor-associated antigens. Studies are currently underway to investigate methods to enhance vaccine strategies, including combinations with standard anticancer therapies or immune-modulating agents. Cancer vaccines are usually well tolerated, with minimal toxicity compared with chemotherapy. This review summarizes selected therapeutic cancer vaccines in late clinical development.

[Review on immunotherapies for lung cancer]

Lung cancer is a highly malignant disease with poor prognosis, most cases are diagnosed at a very late stage. More effective medications or therapies should be developed to improve its prognosis. The advancement of tumor immunity and tumor immunosuppression facilitated the feasibility of immunotherapies for lung cancer. Ipilimumab, antibody to Programmed death-1 (PD-1), Toll-like receptor agonists, liposomal BLP25 (L- BLP25), belagenpumatucel-L, melanoma-associated antigen A3 (MAGE-A3) vaccine and talactoferrin have been proved to be effective for lung cancer through early clinical trials, most of the drugs have moved forward to phase III trials, so as to collect much higher level evidence to support the immunotherapies incorporated into the multidisciplinary treatment of lung cancer. The selection of target patients at appropriate stages, breaking down of tumor immunosuppression as well as the objective measurement of tumor response to the therapy are major challenges for the development of immunotherapies for lung cancer. The clarifying of the mechanism of immune escape led to the above drug development, and immune-senescence has already become the hotspot in this field.

Current status of immunotherapy for the treatment of lung cancer

Immunotherapy is a novel approach for the treatment of systemic malignancies. Passive and adaptive immunotherapy have been applied to the treatment of a wide variety of solid tumors such as malignant melanoma (1), renal cell carcinoma (2) and ovarian cancer (3). Several early clinical trials of immune based therapy for both non-small (NSCLC) and small cell lung cancer (SCLC) have demonstrated limited or no success (3),(4) but recent trials of antigen-specific cancer immunotherapy have shown early therapeutic potential and are now being rigorously evaluated on a larger scale (5). In this communication we briefly review the historic aspects of immune based therapy for solid cancer, describe therapeutic strategies aimed at targeting lung cancer, and discuss limitations of current therapy and future directions of this field.

Active-specific immunotherapy for non-small cell lung cancer

Non-small cell lung cancer constitutes about 85% of all newly diagnosed cases of lung cancer and continues to be the leading cause of cancer-related deaths worldwide. Standard treatment for this devastating disease, such as systemic chemotherapy, has reached a plateau in effectiveness and comes with considerable toxicities. For all stages of disease fewer than 20% of patients are alive 5 years after diagnosis; for metastatic disease the median survival is less than one year. Until now, the success of active-specific immunotherapy for all tumor types has been sporadic and unpredictable. However, the active-specific stimulation of the host's own immune system still holds great promise for achieving non-toxic and durable antitumor responses. Recently, sipuleucel-T (Provenge(®); Dendreon Corp., Seattle, WA) was the first therapeutic cancer vaccine to receive market approval, in this case for advanced prostate cancer. Other phase III clinical trials using time-dependent endpoints, e.g. in melanoma and follicular lymphoma, have recently turned out positive. More sophisticated specific vaccines have now also been developed for lung cancer, which, for long, was not considered an immune-sensitive malignancy. This may explain why advances in active-specific immunotherapy for lung cancer lag behind similar efforts in renal cell cancer, melanoma or prostate cancer. However, various vaccines are now being evaluated in controlled phase III clinical trials, raising hopes that active-specific immunotherapy may become an additional effective therapy for patients with lung cancer. This article reviews the most prominent active-specific immunotherapeutic approaches using protein/peptide, whole tumor cells, and dendritic cells as vaccines for lung cancer.

Dendritic cell-based vaccination in metastatic melanoma patients: phase II clinical trial

Metastatic and chemoresistant melanoma can be a good target of immunotherapy because it is an intractable cancer with a very poor prognosis. Previously, we tested a dendritic cell (DC)-based phase I vaccine, and confirmed that it was safe. In the present study, we performed a phase II trial of a DC vaccine for metastatic melanoma patients with mainly the HLA-A24 genotype, and investigated the efficacy of the vaccine. Twenty-four patients with metastatic melanoma were enrolled into a phase II study of DC-based immunotherapy. The group included 19 HLA-A24-positive (A*2402) patients and 3 HLA-A2-positive (A*0201) patients. The protocol for DC production was similar to that in the phase I trial. Briefly, a cocktail of 5 melanoma-associated synthetic peptides (gp100, tyrosinase, MAGE-A2, MAGE-A3 and MART-1 or MAGE‑A1) restricted to HLA-A2 or A24 and KLH were used for DC pulsing. Finally, DCs were injected subcutaneously (s.c.) into the inguinal region in the dose range of 1-5x107 per shot. The DC ratio (lin-HLA-DR+) of the vaccine was 38.1±13.3% and the frequency of CD83+ DCs was 25.7±20.8%. Other parameters regarding DC processing were not different from phase I. Immune response-related parameters including the ELISPOT assay, DTH reaction to peptide or KLH, DC injection numbers were shown to be related to a good prognosis. The ELISPOT reaction was positive in 75% of the patients vaccinated. The increase of anti-melanoma antigen antibody titer before vaccination was also shown to be a prognosis factor, but that post-vaccination was not. Based on immunohistochemical analysis, CD8 and IL-17 were not involved in the prognosis. Adverse effects of more than grade III were not seen. Overall survival analysis revealed a significant survival prolongation effect in DC-given melanoma patients. These results suggest that peptide cocktail-treated DC vaccines may be a safe and effective therapy against metastatic melanoma in terms of prolongation of overall survival time.

Cancer/testis antigen expression as a predictor for epidermal growth factor receptor mutation and prognosis in lung adenocarcinoma

OBJECTIVES

Immune therapy targeting cancer/testis (CT) antigens improve the survival in several types of solid tumours. The expression of CT antigens is related to poor survival in non-small-cell lung cancer (NSCLC). The epidermal growth factor receptor (EGFR) mutation is the best predictive factor for the sensitivity to tyrosine kinase inhibitors in lung adenocarcinoma. The aim of this study was to elucidate the correlation between the expression of CT antigens and clinicopathological factors, including the EGFR mutation, and to analyse the prognosis in lung adenocarcinoma.

METHODS

Data were collected from a total of 281 lung adenocarcinoma patients who underwent surgery. Among them, 125 cases, whose specimens were too small to extract sufficient DNA and/or RNA, and 2 cases with the coexistence of another histological lung cancer were excluded. A total of 154 patients were reviewed. The expression of CT antigens (melanoma-associated antigen gene [MAGE]-A4 and KK-LC-1) and the EGFR-activating mutation (L858R point mutation in exon 21 and inframe deletion in exon 19) was evaluated by using polymerase chain reaction amplification.

RESULTS

The expression of MAGE-A4 and KK-LC-1 was detected in 14 (9%) and 54 patients (35%) with adenocarcinoma. The EGFR-activating mutation was found in 64 patients (42%). Univariate and multivariate analyses demonstrated that tumours expressing at least one CT antigen were associated with no EGFR mutation (odds ratio = 0.3; 95% confidence interval, 0.14-0.71; P < 0.01). A survival analysis was performed in 135 patients who underwent complete resection and the 5-year overall survival rate was 71.1% in those with any expression of CT antigens and 83.2% in those without expression of the genes (P < 0.04).

CONCLUSION

Two different therapeutic targets, EGFR-activating mutation and CT antigen, have a negative relationship with each other.

Cancer/testis antigens and urological malignancies

Cancer/testis antigens (CTAs) are a group of tumour-associated antigens (TAAs) that display normal expression in the adult testis--an immune-privileged organ--but aberrant expression in several types of cancers, particularly in advanced cancers with stem cell-like characteristics. There has been an explosion in CTA-based research since CTAs were first identified in 1991 and MAGE-1 was shown to elicit an autologous cytotoxic T-lymphocyte (CTL) response in a patient with melanoma. The resulting data have not only highlighted a role for CTAs in tumorigenesis, but have also underscored the translational potential of these antigens for detecting and treating many types of cancers. Studies that have investigated the use of CTAs for the clinical management of urological malignancies indicate that these TAAs have potential roles as novel biomarkers, with increased specificity and sensitivity compared to those currently used in the clinic, and therapeutic targets for cancer immunotherapy. Increasing evidence supports the utilization of these promising tools for urological indications.

The bioinformatics tool box for reproductive biology

Genetics and molecular biology have been instrumental for a better understanding of heritable defects causing human infertility over the past decades. More recently, the field of reproductive biology has harnessed genome biological approaches to gain insight into molecular processes underlying normal and pathological gametogenesis and gamete function. We are currently witnessing yet another quantum leap in our ability to monitor the flow of information from the genome via the transcriptome to the proteome: tiling arrays that cover both strands of a given target genome and RNA-Seq, a method based on ultra-high throughput DNA sequencing, enable us to study noncoding and protein-coding transcripts with unprecedented precision and depth at a reasonable cost. These technologies have spawned a thriving discipline within the bioinformatics field that employs information technology for managing and interpreting biological high-throughput data. This review outlines database projects and online analysis tools useful for life scientists in general and discusses in detail selected projects that have specifically been developed for researchers and clinicians in the field of reproductive biology. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.

TCR gene transfer: MAGE-C2/HLA-A2 and MAGE-A3/HLA-DP4 epitopes as melanoma-specific immune targets

Adoptive therapy with TCR gene-engineered T cells provides an attractive and feasible treatment option for cancer patients. Further development of TCR gene therapy requires the implementation of T-cell target epitopes that prevent “on-target” reactivity towards healthy tissues and at the same time direct a clinically effective response towards tumor tissues. Candidate epitopes that meet these criteria are MAGE-C2_336-344/HLA-A2 (MC2/A2) and MAGE-A3_243-258/HLA-DP4 (MA3/DP4). We molecularly characterized TCRαβ genes of an MC2/A2-specific CD8 and MA3/DP4-specific CD4 T-cell clone derived from melanoma patients who responded clinically to MAGE vaccination. We identified MC2/A2 and MA3/DP4-specific TCR-Vα3/Vβ28 and TCR-Vα38/Vβ2 chains and validated these TCRs in vitro upon gene transfer into primary human T cells. The MC2 and MA3 TCR were surface-expressed and mediated CD8 T-cell functions towards melanoma cell lines and CD4 T-cell functions towards dendritic cells, respectively. We intend to start testing these MAGE-specific TCRs in phase I clinical trial.

Adjuvant immunotherapy for non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the biggest cancer killer in the United States and worldwide. In 2011, there are estimated to be 221,130 new cases of lung cancer in the United States. Over a million people will die of lung cancer worldwide this year alone. When possible, surgery to remove the tumor is the best treatment strategy for patients with NSCLC. However, even with adjuvant (postoperative) chemotherapy and radiation, more than 40% of patients will develop recurrences locally or systemically and ultimately succumb to their disease. Thus, there is an urgent need for developing superior approaches to treat patients who undergo surgery for NSCLC to eliminate residual disease that is likely responsible for these recurrences. Our group and others have been interested in using immunotherapy to augment the efficacy of current treatment strategies. Immunotherapy is very effective against minimal disease burden and small deposits of tumor cells that are accessible by the circulating immune cells. Therefore, this strategy may be ideally suited as an adjunct to surgery to seek and destroy microscopic tumor deposits that remain after surgery. This review describes the mechanistic underpinnings of immunotherapy and how it is currently being used to target residual disease and prevent postoperative recurrences after pulmonary resection in NSCLC.

Emerging cancer vaccines: the promise of genetic vectors

Therapeutic vaccination against cancer is an important approach which, when combined with other therapies, can improve long-term control of cancer. In fact, the induction of adaptive immune responses against Tumor Associated Antigens (TAAs) as well as innate immunity are important factors for tumor stabilization/eradication. A variety of immunization technologies have been explored in last decades and are currently under active evaluation, such as cell-based, protein, peptide and heat-shock protein-based cancer vaccines. Genetic vaccines are emerging as promising methodologies to elicit immune responses against a wide variety of antigens, including TAAs. Amongst these, Adenovirus (Ad)-based vectors show excellent immunogenicity profile and have achieved immunological proof of concept in humans. In vivo electroporation of plasmid DNA (DNA-EP) is also a desirable vaccine technology for cancer vaccines, as it is repeatable several times, a parameter required for the long-term maintenance of anti-tumor immunity. Recent findings show that combinations of different modalities of immunization (heterologous prime/boost) are able to induce superior immune reactions as compared to single-modality vaccines. In this review, we will discuss the challenges and requirements of emerging cancer vaccines, particularly focusing on the genetic cancer vaccines currently under active development and the promise shown by Ad and DNA-EP heterologous prime-boost.

MAGE-A family: attractive targets for cancer immunotherapy

The melonoma-associated antigens family A (MAGE-A) belongs to cancer/testis antigens (CTA) that are expressed in a wide variety of malignant tumors but not in normal adult tissues except for testis. Interestingly, germ cells do not express MHC class I antigen, implying that these gene products should be ideal targets for cancer immunotherapy. The strict tumor-specific expression of MAGE-As has led to several immunotherapeutic trials targeting some of these proteins. In this review, we briefly described the expression and activation mechanism of MAGE-As in cancer. We also summarized the biological functions of MAGE-As in cell progress and the progress of the cancer immunotherapy targeting MAGE-A family.

Personalized medicine for lung cancer: new challenges for pathology

Recent advances in non-small-cell lung cancer (NSCLC) therapy mean the relatively simple discrimination between small-cell and 'non-small-cell' carcinoma is insufficient to determine the best treatment for individual patients. Safety, efficacy and prescribing requirements mandate more specific subtyping of NSCLC for several new drugs: practice made difficult by the tumour heterogeneity combined with the paucity of tissue in most diagnostic samples. Immunohistochemical approaches have emerged as accurate predictors of probable tumour histotype. P63 and/or cytokeratins 5 and 6 and thyroid transcription factor 1 (TTF1) are among the best predictors, respectively, of squamous and adenocarcinoma histology. Molecular characteristics may predict response to both newer molecular targeted agents and traditional cytotoxic agents. Specific mutations in the epidermal growth factor receptor (EGFR) gene as predictors of response to EGFR tyrosine kinase inhibitors (erlotinib, gefitinib) is the first example of markers which predict response to targeted agents. Actual drug targets [e.g. thymidilate synthase (TS) - pemetrexed] or markers of the tumour's ability to repair cytotoxic drug-induced damage [e.g. excision repair cross-complementation group 1 (ERCC1) - cisplatin] may well also complement NSCLC diagnosis. This extended diagnostic requirement from increasingly limited material provided by minimally invasive biopsy techniques poses major challenges for pathology.

Vaccination-induced functional competence of circulating human tumor-specific CD8 T-cells

T-cells specific for foreign (e.g., viral) antigens can give rise to strong protective immune responses, whereas self/tumor antigen-specific T-cells are thought to be less powerful. However, synthetic T-cell vaccines composed of Melan-A/MART-1 peptide, CpG and IFA can induce high frequencies of tumor-specific CD8 T-cells in PBMC of melanoma patients. Here we analyzed the functionality of these T-cells directly ex vivo, by multiparameter flow cytometry. The production of multiple cytokines (IFNγ, TNFα, IL-2) and upregulation of LAMP-1 (CD107a) by tumor (Melan-A/MART-1) specific T-cells was comparable to virus (EBV-BMLF1) specific CD8 T-cells. Furthermore, phosphorylation of STAT1, STAT5 and ERK1/2, and expression of CD3 zeta chain were similar in tumor- and virus-specific T-cells, demonstrating functional signaling pathways. Interestingly, high frequencies of functionally competent T-cells were induced irrespective of patient's age or gender. Finally, CD8 T-cell function correlated with disease-free survival. However, this result is preliminary since the study was a Phase I clinical trial. We conclude that human tumor-specific CD8 T-cells can reach functional competence in vivo, encouraging further development and Phase III trials assessing the clinical efficacy of robust vaccination strategies.

MAGE-C2/CT10 protein expression is an independent predictor of recurrence in prostate cancer

The cancer-testis (CT) family of antigens is expressed in a variety of malignant neoplasms. In most cases, no CT antigen is found in normal tissues, except in testis, making them ideal targets for cancer immunotherapy. A comprehensive analysis of CT antigen expression has not yet been reported in prostate cancer. MAGE-C2/CT-10 is a novel CT antigen. The objective of this study was to analyze extent and prognostic significance of MAGE-C2/CT10 protein expression in prostate cancer. 348 prostate carcinomas from consecutive radical prostatectomies, 29 castration-refractory prostate cancer, 46 metastases, and 45 benign hyperplasias were immunohistochemically analyzed for MAGE-C2/CT10 expression using tissue microarrays. Nuclear MAGE-C2/CT10 expression was identified in only 3.3% primary prostate carcinomas. MAGE-C2/CT10 protein expression was significantly more frequent in metastatic (16.3% positivity) and castration-resistant prostate cancer (17% positivity; p<0.001). Nuclear MAGE-C2/CT10 expression was identified as predictor of biochemical recurrence after radical prostatectomy (p = 0.015), which was independent of preoperative PSA, Gleason score, tumor stage, and surgical margin status in multivariate analysis (p<0.05). MAGE-C2/CT10 expression in prostate cancer correlates with the degree of malignancy and indicates a higher risk for biochemical recurrence after radical prostatectomy. Further, the results suggest MAGE-C2/CT10 as a potential target for adjuvant and palliative immunotherapy in patients with prostate cancer.

Cancer/testis (CT) antigens, carcinogenesis and spermatogenesis

During spermatogenesis, spermatogonial stem cells, undifferentiated and differentiated spermatogonia, spermatocytes, spermatids and spermatozoa all express specific antigens, yet the functions of many of these antigens remain unexplored. Studies in the past three decades have shown that many of these transiently expressed genes in developing germ cells are proto-oncogenes and oncogenes, which are expressed only in the testis and various types of cancers in humans and rodents. As such, these antigens are designated cancer/testis antigens (CT antigens). Since the early 1980s, about 70 families of CT antigens have been identified with over 140 members are known to date. Due to their restricted expression in the testis and in various tumors in humans, they have been used as the target of immunotherapy. Multiple clinical trials at different phases are now being conducted with some promising results. Interestingly, in a significant number of cancer patients, antibodies against some of these CT antigens were detected in their sera. However, antibodies against these CT antigens in humans under normal physiological conditions have yet to be reported even though many of these antigens are residing outside of the blood-testis barrier (BTB), such as in the basal compartment of the seminiferous epithelium and in the stem cell niche in the testis. In this review, we summarize latest findings in the field regarding several selected CT antigens which may be intimately related to spermatogenesis due to their unusual restricted expression during different discrete events of spermatogenesis, such as cell cycle progression, meiosis and spermiogenesis. This information should be helpful to investigators in the field to study the roles of these oncogenes in spermatogenesis.

MAGE-A3/4 and NY-ESO-1 antigens expression in metastatic esophageal squamous cell carcinoma

In the present study we analyzed immunohistochemical expression of MAGE-A 3/4 and NY-ESO-1 in 55 samples of esophageal squamous cell carcinomas (ESCC) and their respective lymph node metastases. To our knowledge this is the first study to assess and compare the expression of these antigens in ESCC lymph node metastases.

Fifty (90.9%) primary ESCC were positive for MAGE-A 3/4 and 53 (96.6%) were positive for NY-ESO-1. MAGE-A 3/4 was expressed in all lymph node metastases and the intensity of expression was high in a majority of cases. NY-ESO-1 was negative in 2 (7.1%) lymph nodes metastases, while the reaction was predominantly moderate in the positive group. In primary tumors MAGE-A 3/4 showed a significantly higher intensity of expression compared to NY-ESO-1 (P=0.047), while in lymph node metastases the intensity of expression was not significantly different (P=0.387). Primary tumors with and without lymph node metastases showed no significant differences in MAGE-A 3/4 (P=0.672) and NY-ESO-1 (P=0.444) expression. Intensity of MAGE-A 3/4 (P=0.461) and NY-ESO-1 (P=0.414) expression in primary tumors was not significantly different compared to the expression in their respective lymph nodes metastases. Expression of MAGE-A 3/4 in primary tumors showed significant positive correlation with primary tumor expression of NY-ESO-1 (P=0.021) but no significant correlation with the expression of MAGE-A 3/4 in lymph node metastases (P=0.056). Expression of NY-ESO-1 in primary tumors showed significant positive correlation with the expression of NY-ESO-1 in lymph node metastases (P=0.001) and significant negative correlation with patients' age (P<0.001). Expression of MAGE-A 3/4 and NY-ESO-1 in primary tumors and lymph node metastases showed no significant correlation with prognostic parameters such as tumor grade and TNM stage (P>0.05). We have shown different levels of MAGE-A 3/4 and NY-ESO-1 expression in almost all specimens of primary tumor and lymph node metastases, suggesting that ESCC may be possible target of immunotherapy and anti-tumor vaccination. High levels of expression in lymph node metastases indicate possible clinical benefit of postoperative vaccine with MAGE-A3 and NY-ESO-1 in advanced stage of disease.

The biology of cancer testis antigens: putative function, regulation and therapeutic potential

Cancer testis antigens (CTA) are a large family of tumor-associated antigens expressed in human tumors of different histological origin, but not in normal tissues except for testis and placenta. This tumor-restricted pattern of expression, together with their strong in vivo immunogenicity, identified CTA as ideal targets for tumor-specific immunotherapeutic approaches, and prompted the development of several clinical trials of CTA-based vaccine therapy. Driven by this practical clinical interest, a more detailed characterization of CTA biology has been recently undertaken. So far, at least 70 families of CTA, globally accounting for about 140 members, have been identified. Most of these CTA are expressed during spermatogenesis, but their function is still largely unknown. Epigenetic events, particularly DNA methylation, appear to be the primary mechanism regulating CTA expression in both normal and transformed cells, as well as in cancer stem cells. In view of the growing interest in CTA biology, the aim of this review is to provide the most recent information on their expression, regulation and function, together with a brief summary of the major clinical trials involving CTA as therapeutic agents. The pharmacologic modulation of CTA expression profiles on neoplastic cells by DNA hypomethylating drugs will also be discussed as a feasible approach to design new combination therapies potentially able to improve the clinical efficacy of currently adopted CTA-based immunotherapeutic regimens in cancer patients.

[Molecular biology of lung cancer series]

INTRODUCTION

MAGE-A3 (Melanoma Associated Antigen-A3) is expressed in cancer cells but not in normal tissues except male germ line cells which are devoid of Major Histocompatibility Complex molecules and therefore do not present MAGE-A3 antigens.

BACKGROUND

MAGE-A3 is expressed in 30 to 60% of non-small cell lung cancers but its function is unknown. Its recognition by cytotoxic T lymphocytes implies its presentation on the cell surface by HLA type A1 molecules that are absent from germ cells.

VIEWPOINTS

MAGE-A3 represents a good target for active anticancer immunotherapy. Some trials, which used MAGE-A3 and an adjuvant showed a strong antigen-specific T-cell response with, perhaps, an improved survival.

CONCLUSION

This needs to be confirmed as an adjuvent therapy by current phase III randomized controlled trials.

Expression and prognostic significance of cancer-testis antigens (CTA) in intrahepatic cholagiocarcinoma

Background

Cancer-testis antigens (CTAs) are suitable targets for cancer-specific immunotherapy. The aim of the study is to investigate the expression of CTAs in intrahepatic cholagiocarcinoma (IHCC) and evaluate their potential therapeutic values.

Methods

Eighty-nine IHCC patients were retrospectively assessed for their expression of CTAs and HLA Class I by immunohistochemistry using the following antibodies: MA454 recognizing MAGE-A1, 57B recognizing multiple MAGE-A (MAGE-A3/A4), E978 recognizing NY-ESO-1, and EMR8-5 recognizing HLA class I. The clinicopathological and prognostic significance of individual CTA markers and their combination were further evaluated.

Results

The expression rates of MAGE-A1, MAGE-A3/4 and NY-ESO-1 were 29.2%, 27.0% and 22.5%, respectively. The concomitant expression of CTAs and HLA class I antigen was observed in 33.7% of the IHCC tumors. We found that positive MAGE-3/4 expression correlated with larger tumor size (≥ 5 cm), tumor recurrence and poor prognosis. Moreover, we identified 52 cases (58.4%) of IHCC patients with at least one CTA marker expression, and this subgroup displayed a higher frequency of larger tumor size and a shorter survival than the other cases. Furthermore, expression of at least one CTA marker was also an independent prognostic factor in patients with IHCC.

Conclusion

Our data suggest that specific immunotherapy targeted CTAs might be a novel treatment option for IHCC patients.

A TCR targeting the HLA-A*0201-restricted epitope of MAGE-A3 recognizes multiple epitopes of the MAGE-A antigen superfamily in several types of cancer

Adoptive immunotherapy using TCR-engineered PBLs against melanocyte differentiation Ags mediates objective tumor regression but is associated with on-target toxicity. To avoid toxicity to normal tissues, we targeted cancer testis Ag (CTA) MAGE-A3, which is widely expressed in a range of epithelial malignancies but is not expressed in most normal tissues. To generate high-avidity TCRs against MAGE-A3, we employed a transgenic mouse model that expresses the human HLA-A*0201 molecule. Mice were immunized with two HLA-A*0201-restricted peptides of MAGE-A3: 112-120 (KVAELVHFL) or MAGE-A3: 271-279 (FLWGPRALV), and T cell clones were generated. MAGE-A3-specific TCR α- and β-chains were isolated and cloned into a retroviral vector. Expression of both TCRs in human PBLs demonstrated Ag-specific reactivity against a range of melanoma and nonmelanoma tumor cells. The TCR against MAGE-A3: 112-120 was selected for further development based on superior reactivity against tumor target cells. Interestingly, peptide epitopes from MAGE-A3 and MAGE-A12 (and to a lesser extent, peptides from MAGE-A2 and MAGE-A6) were recognized by PBLs engineered to express this TCR. To further improve TCR function, single amino acid variants of the CDR3 α-chain were generated. Substitution of alanine to threonine at position 118 of the α-chain in the CDR3 region of the TCR improved its functional avidity in CD4 and CD8 cells. On the basis of these results, a clinical trial is planned in which patients bearing a variety of tumor histologies will receive autologous PBLs that have been transduced with this optimized anti-MAGE-A3 TCR.

Vaccine-induced antibody responses in patients with carcinoma

Cancer vaccines based on defined antigens are capable of inducing antibodies that recognize and kill tumor cells. Antibodies are ideally suited to address minimal residual disease, and vaccination in an adjuvant setting may favorably influence the outcome of a disease. The present article gives a short summary of antibody production by B cells, and the mechanism of action of antibodies, as well as a description of the current methods for measuring antibody responses and for assessing their antitumor efficacy in the context of clinical trials. It concludes with an overview of antibody responses induced by vaccines based on structurally defined tumor-associated antigens tested in patients with carcinomas. Correlation between antibody responses, T-cell responses and clinical outcome has been noted in a few studies, signaling the importance of vaccine design and adjuvants to exploit the interactions of the innate and adaptive immune system. However, humoral responses, which may provide a surrogate marker for T-helper responses and simplify monitoring of large Phase III trials, are still not or incompletely explored in many vaccination trials.