Heterologous reporter expression in the planarian Schmidtea mediterranea through somatic mRNA transfection

Planarians have long been studied for their regenerative abilities. Moving forward, tools for ectopic expression of non-native proteins will be of substantial value. Using a luminescent reporter to overcome the strong autofluorescence of planarian tissues, we demonstrate heterologous protein expression in planarian cells and live animals. Our approach is based on the introduction of mRNA through several nanotechnological and chemical transfection methods. We improve reporter expression by altering untranslated region (UTR) sequences and codon bias, facilitating the measurement of expression kinetics in both isolated cells and whole planarians using luminescence imaging. We also examine protein expression as a function of variations in the UTRs of delivered mRNA, demonstrating a framework to investigate gene regulation at the post-transcriptional level. Together, these advances expand the toolbox for the mechanistic analysis of planarian biology and establish a foundation for the development and expansion of transgenic techniques in this unique model system.

Curing Cancer: Lessons from a Prototype

Simple Summary

Germ cell tumor of the testis (TGCT) teaches us that to cure cancer, we need to acquire and apply proper biological insight and clinical acumen. In 1946, about 90% of patients with metastatic TGCT died within the first year of diagnosis. Today, over 90% of the same patients are curable. This complete reversal in the cure rate of TGCT is not because we have designed better drugs (we have not), but because we have learned how to use the same drugs in the right patients under the right settings. Importantly, TGCT is a prototype stem cell tumor that may hold the key to unlocking the origin of cancers, thereby enhancing our understanding of cancer and improving the cure and care of patients with cancer.

Abstract

Germ cell tumor of the testis (TGCT) is a remarkably curable solid tumor even when it is widely metastatic and patently heterogeneous. It provides invaluable clues about the origin and nature of metastasis and heterogeneity, cancer dormancy and late recurrence, drug sensitivity and resistance, tumor immunity, and spontaneous remission that would enable us to enhance the cure and improve the care of patients with other currently intractable solid tumors. After all, germ cells are primeval stem cells and TGCT are a perfect stem cell tumor for us to investigate a stem cell versus genetic origin of cancer. In many respects, TGCT is a prototype stem cell tumor that will enable us to elucidate the role of differentiation versus dedifferentiation in the evolution of a complex mixed tumor. It will help us decipher relevance of the genome versus the epi-genome in a progenitor cancer stem cell versus a progeny differentiated cancer cell. Importantly, clarification of a cellular context versus the genetic makeup in cancer has immense clinical implications. We postulate a unified theory of cancer derived from seminal TGCT research to improve personalized cancer care. Contrary to current norms and conventional wisdom, we propose that when it concerns a complex rather than simple cancer and a mixed rather than pure tumor (which is practically all solid tumors) multimodal therapy trumps targeted therapy and integrated medicine overrides precision medicine.

Origin of Subsequent Malignant Neoplasms in Patients with History of Testicular Germ Cell Tumor

Simple Summary

Although testicular germ cell tumor (TGCT) carries a high cure rate, some patients still die from it. We investigated the genetic landscape and cellular origins of cancers that develop later in life after treatment for TGCT and found evidence that a common progenitor cell might be responsible for both. This study shows the possible importance of stem-like cells in the development of cancer.

Abstract

Although genetic changes may be pivotal in the origin of cancer, cellular context is paramount. This is particularly relevant in a progenitor germ cell tumor and its differentiated mature teratoma counterpart when it concerns tumor heterogeneity and cancer dormancy in subsequent second malignancies (subsequent malignant neoplasms (SMNs)). From our tumor registry database, we identified 655 testicular germ cell tumor (TGCT) patients who developed SMNs between January 1990 and September 2018. Of the 113 solid organ SMNs, 42 had sufficient tumor tissue available for fluorescence in situ hybridization (FISH) analysis of isochromosome 12p [i(12p)]. We identified seven additional patients for targeted DNA and RNA sequencing of teratomas and adjacent somatic transformation. Finally, we established cell lines from freshly resected post-chemotherapy teratomas and evaluated the cells for stemness expression by flow cytometry and by the formation of teratomas in a xenograft model. In our cohort, SMNs comprising non-germ cell tumors occurred about 18 years after a diagnosis of TGCT. Of the 42 SMNs examined, 5 (12%) contained i(12p) and 16 (38%) had 12p gain. When comparing a teratoma and adjacent somatic transformation, targeted DNA and RNA sequencing demonstrated high concordance. Studies of post-chemotherapy teratoma-derived cell lines revealed cancer-initiating cells expressing multipotency as well as early differentiation markers. For the first time, we demonstrated the prevalence of i(12p) in SMNs and the presence of progenitor cells embedded within mature teratomas after chemotherapy. Our findings suggest a progenitor stem-like cell of origin in SMN and TGCT and highlight the importance of cellular context in this disease.

Somatic Transformation in Metastatic Testicular Germ Cell Tumours - A Different Disease Entity

BACKGROUND/AIM

The occurrence of somatic transformation in germ cell tumour (GCT) is rare, with increased incidence in teratomatous tumours. The aim of this study was to understand the clinical outcomes of patients with metastatic GCT with somatic transformation.

MATERIALS AND METHODS

A retrospective study was conducted in two tertiary cancer centres in London. Between 1998 and 2016, 30 cases of somatic transformation in GCT treated at the Mount Vernon Cancer Centre and St. Bartholomew's Hospital were identified. The median age at diagnosis was 34 years (range=18-56 years). The histological diagnosis at transformation was rhabdomyosarcoma, sarcomatoid yolk sac, sarcoma (non-specified), clear cell carcinoma, adenocarcinoma and primitive neuro ectodermal tumour (PNET).

RESULTS

The 5-year survival rate of all patients was 47%, and that of patients with testicular primary (n=26 patients) was 37%.

CONCLUSION

Somatic transformation component in testicular GCTs is generally considered to be an adverse prognostic factor, however, a reasonable 5-year overall survival rate (87.5%) was observed in patients who present with this at first diagnosis.

Functional characterization of the transcriptional regulatory elements of three highly expressed constitutive genes in the jewel wasp, Nasonia vitripennis

The jewel wasp, Nasonia vitripennis Ashmead (Hymenoptera: Pteromalidae), is an easily reared parasitoid that is providing an ever increasingly malleable model for examining the biology and genetics of Hymenoptera. Utilizing genomic and transcriptome resources, 5' upstream transcriptional regulatory sequences (TREs) from three highly expressed genes were identified and cloned. Criteria for TRE selection included the presence of an adjacent gene 5' of the translation initiation site. One gene was methylated whereas the other two were nonmethylated. Each TRE, heat-shock protein 70 (hsp70), activator of 90 kDa hsp ATPase protein 1 (hsp90A), and lipid storage droplet surface-binding protein 1 (lsdp) was linked with enhanced green fluorescent protein (EGFP) coding sequence and cloned into both pDP9e somatic and piggyBac germline transformation vectors. EGFP expression patterns under control of each TRE were compared with patterns of DsRed fluorescence produced from the transformation vector cassette. Functional activity of each TRE was observed in cultured Spodoptera frugiperda 9 (Sf9) cells and Drosophila melanogaster as well as in N. vitripennis embryos demonstrating that all three sequences had functional transcriptional regulatory activity in three different insect orders. Identification and functional characterization of these three TREs will provide critical and necessary resources for further genetic analyses of N. vitripennis, Hymenoptera and other insects.

In vivo electroporation of DNA into the wing epidermis of the butterfly, Bicyclus anynana

The direct transfer of genes into differentiated insect tissues is a useful method of determining gene function because it circumvents the need to perform germ line transformations and of having information on tissue-specific gene promoters. Here in vivo gene delivery is achieved through electroporation of a reporter gene into the pupal forewing of the butterfly Bicyclus anynana (Butler) (Lepidoptera: Nymphalidae). Plasmids containing the coding sequence for enhanced green fluorescent protein (EGFP), driven by the Drosophila heat-shock promoter hsp70, were successfully expressed in epidermal cells after plasmid injection followed by electroporation and heat shock. EGFP expression was restricted to the vicinity of the injection and electroporation site, but the number of transformed cells varied from a few to over 5000 cells. Electroporation parameters were optimized in order to maximize the number of transformed cells while minimizing the extent of damage to the adult wing. While certain electrical parameters were well tolerated by the wing tissue, the physical damage caused by the insertion of the tungsten electrodes led to frequent disruptions of the adult wing pattern around the puncture sites. While this technique can be useful to test the correct expression of marker genes (such as EGFP) in newly build plasmids immediately following their injection, its potential use in testing the function of candidate genes in wing pattern formation is limited.