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Signal transducer and activator of transcription 3 (STAT3) has been recognized with dual effects in provision of cancer; either tumor inductive or immune suppressive. Recent findings considering the role of STAT3 in stem cells and cancer stem cell regulation, but its role in gastric cancer stem cells (GCSCs) and modulating the Th17/Treg balance is unknown. In the present study, we aimed to evaluate the role of activated STAT3 in GCSCs and Th17/ Treg cell paradigm. In completion of our previous results, the findings here indicate that gastro-spheroids, as a model of GCSCs, represent higher level of STAT3 activity, up-regulation of TGF-b and VEGF with downregulation of IL-6. On the other hand, treatment of normal naïve T cells with conditioned medium derived from gastro-spheroids promotes T cell differentiation toward cells with a higher level of FOXP3, TGF-b, and IL-10 expression which is indicative of Treg cells. Suppression of STAT3 activation in cancer cells by using Stattic small molecule treatment, decreases stemness features (i.e. spheroid formation and integrity, stemness gene expression and in vivo tumorigenicity capacity) and downregulates TGF-b in the cancer cells. Furthermore, co-culture of conditioned medium of STAT3 inhibited cancer cells with normal PBMCs leads to reduction in the percentage of Treg accompanied with increase of Th17 cells with a decrease in the secretion of TGF-b and increase in IFN-γ in T cells under differentiation. Therefore, targeting the STAT3 pathway in cancer cells seems to control the tumor formation and also impact on immune cells shifting to antitumor Th17 population.

Embryogenesis is regarded the 'miracle of life', yet numerous aspects of this process are not fully understood. As the embryo grows in the mother's womb, immune components, stem cells and microenvironmental cues cooperate among others to promote embryonic development. Evidently, these key players are frequently associated with transplantation failure and tumor growth. While the fields of transplantation and cancer biology do not overlap, both can be viewed from the perspective of an embryo. As an 'unrejected transplant' and a 'benign tumor', lessons from embryonic development may reveal features of transplants and tumors that have been overlooked. Therefore, eavesdropping at these natural complex events during pregnancy may inspire more durable approaches to arrest transplant rejection or cancer progression.

Embryogenesis is regarded the 'miracle of life', yet numerous aspects of this process are not fully understood. As the embryo grows in the mother's womb, immune components, stem cells and microenvironmental cues cooperate among others to promote embryonic development. Evidently, these key players are frequently associated with transplantation failure and tumor growth. While the fields of transplantation and cancer biology do not overlap, both can be viewed from the perspective of an embryo. As an 'unrejected transplant' and a 'benign tumor', lessons from embryonic development may reveal features of transplants and tumors that have been overlooked. Therefore, eavesdropping at these natural complex events during pregnancy may inspire more durable approaches to arrest transplant rejection or cancer progression.

Adaptive T-cell immunotherapy holds great promise for the successful treatment of leukemia, as well as other types of cancers. More recently, it was also shown to be an effective treatment option for chronic virus infections in immunosuppressed patients. Autologous or allogeneic T cells used for immunotherapy are usually genetically modified to express novel T-cell or chimeric antigen receptors. The production of such cells was significantly simplified with the CRISPR/Cas system, allowing for the deletion or insertion of novel genes at specific locations within the genome. In this review, we describe recent methodological breakthroughs that were important for the conduction of these genetic modifications, summarize crucial points to be considered when conducting such experiments, and highlight the potential pitfalls of these approaches.

5-Fluorouracil (5-FU) in combination with curcumin has been widely investigated for colon carcinoma cancer. The combination therapy using drug delivery systems will hopefully result in improved therapeutic efficacy, targeted delivery and controlled release of therapeutic agents. However, development of single drug carriers for simultaneous administration of both hydrophobic (curcumin) and hydrophilic (5-FU) drugs is still challenging. Here, the micelle-crosslinked hydrogel was synthesized through a reversible Schiff’s based reaction between gelatin-hydrazide (Gel-ADH) and self-assembled Pluronic F127-benzaldehyde (PF127-CHO) micelles. The 5-FU was incorporated in hydrogel network and curcumin was incorporated in core of micelles embedded in hydrogel. The in vitro drugs release profile in pH 6.8 and 7.4 exhibited a pH-responsive release pattern and showed more sustain release of 5-FU in combination with curcumin. The exposure of the combined drug formulation in colon cancer cells (HT-29) proved the enhanced anticancer effects. The synergistic inhibitory effects on the cell cycle progression and cell proliferation in HT-29 cells were also confirmed. The developed hydrogel showed the more efficacy for the simultaneous administration of two drugs with different hydrophilicity.

Failure of treatment strategies against cancers is a major issue engaging many scientists to investigate the possible resistance factors. Cancer stem cells (CSCs) subvert promising therapeutic methods by developing resistant cancers. These pluripotent cells are located in individual microenvironments called cancer niche. CSCs affect the immune cells and on the flip side, the immune cells in the cancer niche influence them. Thereby, the interaction between CSCs and immune cells in cancer niche needs to be clearly studied in order to develop novel efficient methods of immune-based cancer treatment. In this article, we review literature about the suggested methods of CSC escape from immune responses and the effect of cancer niche characteristics on the ability of CSCs to develop resistant strains of cancers. Moreover, we discuss immune-mediated tumor targeting methods and bring in trials focused on CSC targeted therapies. We aim to help physicians to reach a consensus about using CSC-targeted immunotherapy methods and emerge novel immunotherapy methods through disrupting the interaction between immune cells and CSCs in the tumor microenvironment.

Gastric cancer stem cells (GCSCs), a small population among tumor cells, are responsible for tumor initiation, development, metastasis, and recurrence. They play a crucial role in immune evasion, immunomodulation, and impairment of effector immunity and believed to be emerged to change the balance of the immune system, importantly CD4+ T cells in the chronic inflamed tumor site. However, different subtypes of innate and adaptive immune cells are involved in the formation of the immune system in the tumor microenvironment, we would look at T cells in this study. Tumor microenvironment induces differentiation of CD4+ T cells into different subsets of T cells, mainly suppressive regulatory T cells (Treg), and T helper 17 (Th17) cells, although their exact role in tumor immunity is still under debate depending on tumor types and stages. Counterbalance between Th17 and Treg cells in the gastrointestinal system result in the homeostasis and normal function of the immune system, particularly mucosal immunity. Recent data demonstrated a high infiltration of Th17 and Treg cells into the gastric tumor site and proved that tumor microenvironment might disturb the balance between Th17 and Treg. It is possible to assume an association between activation of CSCs which contribute to metastasis in late stages, and the imbalanced Th17/Treg cells observed in advanced gastric cancer patients. This review intends to clarify the importance of gastric tumor microenvironment specifically CSCs in relation to Th17/Tregs balance firstly and to highlight the relevance of imbalanced Th17/Treg subsets in determining the stages and behavior of the tumor secondly. Finally, the present study suggests a clinical approach looking at the plasticity of T cells with a focus on Th17 as a promising dedicated arm in cancer immunotherapy.