Genetically engineered suicide gene in mesenchymal stem cells using a Tet-On system for anaplastic thyroid cancer

In Vivo Stem Cell Imaging Principles and Applications

Stem cells are the foundational cells for every organ and tissue in our body. Cell-based therapeutics using stem cells in regenerative medicine have received attracting attention as a possible treatment for various diseases caused by congenital defects. Stem cells such as induced pluripotent stem cells (iPSCs) as well as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and neuroprogenitors stem cells (NSCs) have recently been studied in various ways as a cell-based therapeutic agent. When various stem cells are transplanted into a living body, they can differentiate and perform complex functions. For stem cell transplantation, it is essential to determine the suitability of the stem cell-based treatment by evaluating the origin of stem, the route of administration, in vivo bio-distribution, transplanted cell survival, function, and mobility. Currently, these various stem cells are being imaged in vivo through various molecular imaging methods. Various imaging modalities such as optical imaging, magnetic resonance imaging (MRI), ultrasound (US), positron emission tomography (PET), and single-photon emission computed tomography (SPECT) have been introduced for the application of various stem cell imaging. In this review, we discuss the principles and recent advances of in vivo molecular imaging for application of stem cell research.

Stem cells therapy for thyroid diseases: progress and challenges

Background

Thyroid hormones are indispensable for organ development and maintaining homeostasis. Thyroid diseases, including thyroiditis and thyroid cancer, affect the normal secretion of hormones and result in thyroid dysfunction.

Objective

This review focuses on therapeutic applications of stem cells for thyroid diseases.

Methods

A literature search of Medline and PubMed was conducted (January 2000–July 2021) to identify recent reports on stem cell therapy for thyroid diseases.

Results

Stem cells are partially developed cell types. They have the capacity to form specialized cells. Besides embryonic stem cells and mesenchymal stem cells, organ resident stem cells and cancer stem cells are recently reported to have important roles in forming organ specific cells and cancers. Stem cells, especially mesenchymal stem cells, have anti-inflammatory and anticancer functions as well.

Conclusions

This review outlines the therapeutic potency of embryonic stem cells, mesenchymal stem cells, thyroid resident stem cells, and thyroid cancer stem cells in thyroid cells’ regeneration, thyroid function modulation, thyroiditis suppression, and antithyroid cancers. Stem cells represent a promising form of treatment for thyroid disorders.

Mesenchymal Stem Cell-Based COVID-19 Therapy: Bioengineering Perspectives

The novel pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). Mesenchymal stem cells (MSCs) are currently utilized in clinics for pulmonary inflammatory diseases, including acute respiratory distress syndrome and acute lung injury. Given that MSCs offer a promising treatment against COVID-19, they are being used against COVID-19 in more than 70 clinical trials with promising findings. Genetically engineered MSCs offer promising therapeutic options in pulmonary diseases. However, their potential has not been explored yet. In this review, we provide perspectives on the functionally modified MSCs that can be developed and harnessed for COVID-19 therapy. Options to manage the SARS-CoV-2 infection and its variants using various bioengineering tools to increase the therapeutic efficacy of MSCs are highlighted.

CircRNA: A novel potential strategy to treat thyroid cancer (Review)

Thyroid cancer (TC) is the most common type of endocrine cancer. Over the last 50 years, the global incidence of TC has been increasing. The survival rate of TC is higher than that of most other types of cancer, but it depends on numerous factors, including the specific type of TC and stage of the disease. Circular RNAs (circRNAs) are a new class of long noncoding RNA with a closed loop structure that have a critical role in the complex gene regulatory network that controls the emergence of TC. The most important function of circRNAs is their ability to specifically bind to microRNAs. In addition, the biological functions of circRNAs also include interactions with proteins, regulation of the transcription of genes and acting as translation templates. Based on the characteristics of circRNAs, they have been identified as potential biomarkers for the diagnosis of tumors. In the present review, the function and significance of circRNAs and their potential clinical implications for TC were summarized. Furthermore, possible treatment approaches involving the use of mesenchymal stem cells (MSCs) and exosomes derived from MSCs as carriers to load and transport circRNAs were discussed.

HSV-TK Expressing Mesenchymal Stem Cells Exert Inhibitory Effect on Cervical Cancer Model

A growing area of research is focused on cancer therapy, and new therapeutic approaches are welcomed. Mesenchymal stem cell (MSC)-based gene therapy is a promising strategy in oncology. Intrinsic tropism and migration to tumor microenvironment with off lights are attractive features of this type of cell carrier. In this way, suicide genes have also found a good platform for better performance and have shown a stronger anti-tumor mechanism by riding on mesenchymal cells. In this study, we investigated the anti-tumor activity of intratumoral injected MSCs transduced with a lentivector expressing the HSV/TK in a mouse cervical cancer model. Following the injection of MSCs transduced with lentivector carrying TK, MSCs alone or PBS into the mice tumor, ganciclovir was administered intraperitoneally during 14 days, and tumor size, survival time, natural killer (NK) cells and cytotoxic T lymphocyte (CTL) activities were assessed. We demonstrated that combination of suicide therapy and cell therapy leading m,to successful tumor inhibition. Significant reduction in tumor size was detected in test group in comparison with controls. Also, potent antitumor NK and CTL activity was seen in treatment group in comparison with controls. Our data demonstrated that the mesenchymal cells expressing TK had inhibitory effect on cervical cancer model.

Mesenchymal stem cells engineered by modified polyethylenimine polymer for targeted cancer gene therapy, in vitro and in vivo

Cell-based delivery system is a promising strategy to protect therapeutic agents from the immune system and provide targeted delivery. Mesenchymal stem cells (MSCs) have recently been introduced as an encouraging vehicle in cell-based gene therapy due to their unique features including tumor-tropic property and migratory ability. However, gene transfer into MSCs is limited due to low efficiency and cytotoxicity of carriers. In this study, we designed a novel delivery system based on polyethylenimine (PEI₂₅ ) to improve these features of carrier and transfect plasmid encoding TRAIL to MSCs. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand of TNF family with selective effect on cancerous cells. Then, death induction and migration ability of TRAIL-expressing MSCs was studied in melanoma cells. The effect of engineered-MSCs as an antitumor vehicle was also investigated in mice bearing melanoma cells. Our findings indicated that heterocyclic amine derivative of PEI₂₅ showed significant improvement in MSCs viability determined by MTT assay and gene expression using fluorescent microscopy, flow cytometry, and Western blot analysis. We observed that engineered-MSCs could migrate toward and induce cell death in B16F0 cells in vitro. The single administration of TRAIL-expressing MSCs could delay tumor appearance and efficiently reduce tumor weights. Hematoxylin and eosin staining of tumor sections revealed extensive neoplastic cells necrosis. Furthermore, engineered-MSCs could migrate and localize to tumors sites within 5 days. Our results indicated that MSCs engineered by modified-PEI/TRAIL complexes could be considered as a promising cellular vehicle for targeted tumor suppression.

Need for Specialized Therapeutic Stem Cells Banks Equipped with Tumor Regression Enzymes and Anti-Tumor Genes

Stem cells are currently being used in many clinical trials for regenerative purposes. These are promising results for stem cells in the treatment of several diseases, including cancer. Nevertheless, there are still many variables which should be addressed before the application of stem cells for cancer treatment. One approach should be to establish well-characterized therapeutic stem cell banks to minimize the variation in results from different clinical trials and facilitate their effective use in basic and translational research.

IGF-1 overexpression improves mesenchymal stem cell survival and promotes neurological recovery after spinal cord injury

BACKGROUND

Survival and therapeutic actions of bone marrow-derived mesenchymal stem cells (BMMSCs) can be limited by the hostile microenvironment present during acute spinal cord injury (SCI). Here, we investigated whether BMMSCs overexpressing insulin-like growth factor 1 (IGF-1), a cytokine involved in neural development and injury repair, improved the therapeutic effects of BMMSCs in SCI.

METHODS

Using a SCI contusion model in C57Bl/6 mice, we transplanted IGF-1 overexpressing or wild-type BMMSCs into the lesion site following SCI and evaluated cell survival, proliferation, immunomodulation, oxidative stress, myelination, and functional outcomes.

RESULTS

BMMSC-IGF1 transplantation was associated with increased cell survival and recruitment of endogenous neural progenitor cells compared to BMMSC- or saline-treated controls. Modulation of gene expression of pro- and anti-inflammatory mediators was observed after BMMSC-IGF1 and compared to saline- and BMMSC-treated mice. Treatment with BMMSC-IGF1 restored spinal cord redox homeostasis by upregulating antioxidant defense genes. BMMSC-IGF1 protected against SCI-induced myelin loss, showing more compact myelin 28 days after SCI. Functional analyses demonstrated significant gains in BMS score and gait analysis in BMMSC-IGF1, compared to BMMSC or saline treatment.

CONCLUSIONS

Overexpression of IGF-1 in BMMSC resulted in increased cell survival, immunomodulation, myelination, and functional improvements, suggesting that IGF-1 facilitates the regenerative actions of BMMSC in acute SCI.

Gene Therapy Leaves a Vicious Cycle

The human genetic code encrypted in thousands of genes holds the secret for synthesis of proteins that drive all biological processes necessary for normal life and death. Though the genetic ciphering remains unchanged through generations, some genes get disrupted, deleted and or mutated, manifesting diseases, and or disorders. Current treatment options—chemotherapy, protein therapy, radiotherapy, and surgery available for no more than 500 diseases—neither cure nor prevent genetic errors but often cause many side effects. However, gene therapy, colloquially called “living drug,” provides a one-time treatment option by rewriting or fixing errors in the natural genetic ciphering. Since gene therapy is predominantly a viral vector-based medicine, it has met with a fair bit of skepticism from both the science fraternity and patients. Now, thanks to advancements in gene editing and recombinant viral vector development, the interest of clinicians and pharmaceutical industries has been rekindled. With the advent of more than 12 different gene therapy drugs for curing cancer, blindness, immune, and neuronal disorders, this emerging experimental medicine has yet again come in the limelight. The present review article delves into the popular viral vectors used in gene therapy, advances, challenges, and perspectives.

Treatment of advanced gastrointestinal cancer with genetically modified autologous mesenchymal stem cells: Results from the phase 1/2 TREAT-ME-1 trial

TREAT-ME-1, a Phase 1/2 open-label multicenter, first-in-human, first-in-class trial, evaluated the safety, tolerability and efficacy of treatment with genetically modified autologous mesenchymal stromal cells (MSC), MSC_ apceth_101, in combination with ganciclovir in patients with advanced gastrointestinal adenocarcinoma. Immunological and inflammatory markers were also assessed. All patients (3 in Phase 1; 7 in Phase 2) received three treatment cycles of MSC_apceth_101 at one dose level on Day 0, 7, and 14 followed by ganciclovir administration according to the manufacturer's instructions for 48─72 h after MSC_apceth_101 injection. Ten patients were treated with a total dose of 3.0 x 10⁶ cells/kg MSC_apceth_101. 36 adverse events and six serious adverse events were reported. Five patients achieved stable disease (change in target lesions of -2 to +28%). For all patients, the median time to progression was 1.8 months (95% CI: 0.5, 3.9 months). Median overall survival could not be estimated as 8/10 patients were still alive at the end of the study (1 year) and therefore censored. Post-study observation of patients showed a median overall survival of 15.6 months (ranging from 2.2─27.0 months). Treatment with MSC_apceth_101 and ganciclovir did not induce a consistent increase or decrease in levels of any of the tumor markers analyzed. No clear trends in the immunological markers assessed were observed. MSC_apceth_101 in combination with ganciclovir was safe and tolerable in patients with advanced gastrointestinal adenocarcinoma, with preliminary signs of efficacy in terms of clinical stabilization of disease.

Migration of mesenchymal stem cells to tumor xenograft models and in vitro drug delivery by doxorubicin

Mesenchymal stem cells (MSCs) show therapeutic effects in various types of diseases. MSCs have been shown to migrate towards inflamed or cancerous tissues, and visualized after sacrificing the animal. MSCs are able to deliver drugs to target cells, and are an ideal candidate for cancer therapy. The purpose of this study was to track the migration of MSCs in tumor-bearing mice; MSCs were also used as drug delivery vehicles. Human breast cancer cells (MDA-MB-231) and anaplastic thyroid cancer cells (CAL62) were transduced with lentiviral particles, to express the Renilla luciferase and mCherry (mCherry-Rluc) reporter genes. Human bone marrow-derived MSCs were transduced with lentiviral particles, to express the firefly luciferase and enhanced green fluorescence protein (Fluc2-eGFP) reporter genes (MSC/Fluc). Luciferase activity of the transduced cells was measured by bioluminescence imaging (BLI). Further in vitro migration assays were performed to confirm cancer cells conditioned medium dependent MSC and doxorubicin (DOX) treated MSC migration. MSCs were loaded with DOX, and their therapeutic effects against the cancer cells were studied in vitro. In vivo MSC/Fluc migration in mice having thyroid or breast cancer xenografts was evaluated after systemic injection. Rluc activity of CAL62/Rluc (R2=0.911), MDA-MB-231/Rluc (R2=0.934) cells and Fluc activity of MSC/Fluc (R2=0.91) cells increased with increasing cell numbers, as seen by BLI. eGFP expression of MSC/Fluc was confirmed by confocal microscopy. Similar migration potential was observed between MSC/Fluc and naïve MSCs in migration assay. DOX treated MSCs migration was not decreased compared than MSCs. Migration of the systemically injected MSC/Fluc cells into tumor xenografts (thyroid and breast cancer) was visualized in animal models (p<0.05) and confirmed by ex vivo (p<0.05) BLI. Additionally, MSCs delivered DOX to CAL62/Rluc and MDA-MB-231/Rluc cells, thereby decreasing their Rluc activities. In this study, we confirmed the migration of MSCs to tumor sites in cancer xenograft models using both in vivo and ex vivo BLI imaging. DOX-pretreated MSCs showed enhanced cytotoxic effects. Therefore, this noninvasive reporter gene (Fluc2)-based BLI may be useful for visualizing in vivo tracking of MSCs, which can be used as a drug delivery vehicle for cancer therapy.

Construction and characterization of regulated cycle inhibiting factors induced upon Tet-On system in human colon cancer cell lines

A previous study has proven that cycle inhibiting factors (Cifs) inhibit Cullin E3 ubiquitin ligases, resulting in cell cycle arrest. More importantly, Cifs are also involved in cancer progression by deamidating Nedd8. Here we aimed to explore a novel insight into the treatment implications of Cifs in colon cancers by Tet-on system. The anticancer activity of Cif by doxycycline induction was investigated in the colon cell lines based upon Tet-On system. The expression of Cif in the colon cancer cells was determined by western blot. Furthermore, the cell viability and flow cytometry analysis were respectively performed to evaluate the cell proliferation and survival of colon cells. More importantly, the p21 and p27 levels were also evaluated after the induction of Cif with Tet-On system. Multiple clones of colon cancer cells for doxycycline-regulated Cif expression were constructed for maintenance purposes including HCT116 and SW480 cell lines. The result of western blot displayed good inducibility of expressing Cif in the cell lines. The clones with Cif preserved their transformed phenotype compared with the control group (clones with GFP or with Cif), in terms of the inhibition of cancer cell proliferation and survival. Furthermore, western blot analysis showed that p27 and p21 were accumulated in the clones with Cif, compared with the colon cancer cell lines with GFP or with Cif. Using the Tet-On system, we developed an efficient approach toward generation of colon cancer cells induced with Cif. These engineered colons tightly controlled Cif expression in vitro, which is a good inducible model system for cancer treatment.