Prediction of recurrence using exfoliative cytology and melanoma‐associated antigen‐A mRNA analysis following wide excision of oral squamous cell carcinoma: short report

N. Mollaoglu, P. Metzler, J. Zenk, E. Nkenke, F. W. Neukam and J. Ries
Prediction of recurrence using exfoliative cytology and melanoma‐associated antigen‐A mRNA analysis following wide excision of oral squamous cell carcinoma: short report Background: Oral squamous cell carcinoma (OSCC) is the sixth most common cancer. The local recurrence of OSSC might result from the existence of occult cancer cells around tumour margins. Exfoliative cytology has lately gained great importance as a method for obtaining RNA samples from suspicious oral mucosal lesions in order to carry out molecular diagnosis. In addition, melanoma associated‐A antigens (MAGE‐A) are expressed in various tumours and their detection is a highly accurate sign that cancer cells are present. Objective: The prediction of a recurrence using MAGE‐A mRNA expression analysis to follow‐up OSCC cases using a newly established molecular diagnostic technique applied to cytological materials. Methods: RNA was extracted from three recurrent OSCC cases and from 20 healthy volunteers as a control group using a cytobrush. The expression of MAGE‐A3, A4, A6, A10 and A12 was investigated in these specimens using quantitative real‐time (RT‐PCR). Results: There was no expression of MAGE‐A in the specimens of normal oral mucosa. However, the expression analysis of five different MAGE‐A genes indicated a high potential for malignant change in biopsy‐proven recurrent OSCC cases. Except for MAGE‐A10, the rest of the genes were expressed in different ratios by the three recurrent cases, which had been determined on histopathology to be OSCC or carcinoma in situ. Conclusion: It is suggested that analysis of MAGE‐A expression may be used as a risk prediction method in the diagnosis of recurrence after wide excision of OSCC to enhance the accuracy of exfoliative cytology, which has limitations due to false negative and false positive results.     

Analysis of a rare melanoma patient with a spontaneous CTL response to a MAGE-A3 peptide presented by HLA-A1

We describe an HLA-A1 melanoma patient who has mounted a spontaneous cytolytic T cell (CTL) response against an antigenic peptide encoded by gene MAGE-A3 and presented by HLA-A1. The frequency of anti-MAGE-3.A1 CTLp was 5×10⁻⁷ of the blood CD8 cells, with a dominant clonotype which was present in six out of seven independent anti-MAGE-3.A1 CTL clones. After vaccination with a recombinant poxvirus coding for the MAGE-3.A1 antigen, the blood frequency of anti-MAGE-3.A1 CTLp increased tenfold. Twenty-two independent CTL clones were derived. Surprisingly, only one of them corresponded to the dominant clonotype present before vaccination. Two new clonotypes were repeated 12 and 7 times, respectively. Our interpretation of these results is that the spontaneous anti-MAGE-3.A1 CTL response pre-existing to vaccination was polyclonal, and that the vaccine restimulated only some of these clones. To estimate the incidence of spontaneous anti-MAGE-3.A1 CTL responses in melanoma patients with a tumor expressing gene MAGE-A3, we measured the blood frequency of anti-MAGE-3.A1 T cells in 45 patients, and found only two clear responses.     

Identification of novel small molecules that inhibit protein-protein interactions between MAGE and KAP-1

The Class I MAGE proteins are normally expressed only in developing germ cells but are often aberrantly expressed in malignancies, particularly melanoma, making them good therapeutic targets. MAGE proteins promote tumor survival by binding to the RBCC region of KAP-1 and suppressing p53. Although, suppression of MAGE expression, by RNA interference, relieves p53 suppression and inhibits tumor growth, its therapeutic uses are limited by lack of methods for systemic delivery of small interfering RNA. To overcome this barrier, we sought to discover chemical compounds that inhibit binding between MAGE and KAP-1 proteins. Based on previously published effects of MAGE suppression, we developed a strategy for screening a small molecule library based on selective death of MAGE positive cells, activation of p53 and lack of caspase activity. We screened the Maybridge HitFinder library of compounds and eight compounds fulfilled these criteria. Seven of these compounds interfered with co-precipitation of MAGE and KAP-1, and three interfered with binding of MAGE and KAP-1 in a mammalian two hybrid assay. We now report identification of three potential compounds that interfere with MAGE/KAP-1 binding and can be developed as novel chemo-therapeutic agents for treatment of advanced melanoma and other cancers.     

Recent advances in plasmid-based tools for establishing novel microbial chassis

A key challenge for domesticating alternative cultivable microorganisms with biotechnological potential lies in the development of innovative technologies. Within this framework, a myriad of genetic tools has flourished, allowing the design and manipulation of complex synthetic circuits and genomes to become the general rule in many laboratories rather than the exception. More recently, with the development of novel technologies such as DNA automated synthesis/sequencing and powerful computational tools, molecular biology has entered the synthetic biology era. In the beginning, most of these technologies were established in traditional microbial models (known as chassis in the synthetic biology framework) such as Escherichia coli and Saccharomyces cerevisiae, enabling fast advances in the field and the validation of fundamental proofs of concept. However, it soon became clear that these organisms, although extremely useful for prototyping many genetic tools, were not ideal for a wide range of biotechnological tasks due to intrinsic limitations in their molecular/physiological properties. Over the last decade, researchers have been facing the great challenge of shifting from these model systems to non-conventional chassis with endogenous capacities for dealing with specific tasks. The key to address these issues includes the generation of narrow and broad host plasmid-based molecular tools and the development of novel methods for engineering genomes through homologous recombination systems, CRISPR/Cas9 and other alternative methods. Here, we address the most recent advances in plasmid-based tools for the construction of novel cell factories, including a guide for helping with “build-your-own” microbial host.     

Cytosolic Iron-Sulfur Assembly Is Evolutionarily Tuned by a Cancer-Amplified Ubiquitin Ligase

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Tumor-associated-antigens or osteosarcoma cell line lysates: two efficient methods for in vitro generation of CTLs with special regard to MHC-I restriction

The expression of tumor associated antigens (TAA) in osteosarcoma cell lines allowed us to design an in vitro model for the generation of TAA-specific CTLs. Since the MHC-I-restriction of these peptides represents the major obstacle to clinical applications, we studied a second method for the generation of CTLs starting from osteosarcoma cell line lysates and PBMCs of HLA-I compatible healthy donors. TAA-specific CTLs showed high and homogeneous cytotoxic response against each peptide; high levels of IFN-γ were released by osteosarcoma cell line lysate specific-CTLs in response to the osteosarcoma cell line they were activated for. The MHC-I dependent osteosarcoma cell line lysate-specific CTLs activity was proved by the indifference against the HLA-I-negative erytroleukaemia cell line K562 and by the absence of IFN-γ production with the addition of HLA-class I blocking antibodies. These two methods may be considered the model for the autologous setting in the context of immunotherapeutic approaches for osteosarcoma patients.