Transcriptional Fluctuations Govern the Serum-Dependent Cell Cycle Duration Heterogeneities in Mammalian Cells.

Mammalian cells exhibit a high degree of intercellular variability in cell cycle period and phase durations. However, the factors orchestrating the cell cycle duration heterogeneities remain unclear. Herein, by combining cell cycle network-based mathematical models with live single-cell imaging studies under varied serum conditions, we demonstrate that fluctuating transcription rates of cell cycle regulatory genes across cell lineages and during cell cycle progression in mammalian cells majorly govern the robust correlation patterns of cell cycle period and phase durations among sister, cousin, and mother-daughter lineage pairs. However, for the overall cellular population, alteration in the serum level modulates the fluctuation and correlation patterns of cell cycle period and phase durations in a correlated manner. These heterogeneities at the population level can be fine-tuned under limited serum conditions by perturbing the cell cycle network using a p38-signaling inhibitor without affecting the robust lineage-level correlations. Overall, our approach identifies transcriptional fluctuations as the key controlling factor for the cell cycle duration heterogeneities and predicts ways to reduce cell-to-cell variabilities by perturbing the cell cycle network regulations.

Combinatorial approaches to effective therapy in glioblastoma (GBM): Current status and what the future holds.

The aggressive and recurrent nature of glioblastoma is multifactorial and has been attributed to its biological heterogeneity, dysfunctional metabolic signaling pathways, rigid blood-brain barrier, inherent resistance to standard therapy due to the stemness property of the gliomas cells, immunosuppressive tumor microenvironment, hypoxia and neoangiogenesis which are very well orchestrated and create the tumor's own highly pro-tumorigenic milieu. Once the relay of events starts amongst these components, eventually it becomes difficult to control the cascade using only the balanced contemporary care of treatment consisting of maximal resection, radiotherapy and chemotherapy with temozolamide. Over the past few decades, implementation of contemporary treatment modalities has shown benefit to some extent, but no significant overall survival benefit is achieved. Therefore, there is an unmet need for advanced multifaceted combinatorial strategies. Recent advances in molecular biology, development of innovative therapeutics and novel delivery platforms over the years has resulted in a paradigm shift in gliomas therapeutics. Decades of research has led to emergence of several treatment molecules, including immunotherapies such as immune checkpoint blockade, oncolytic virotherapy, adoptive cell therapy, nanoparticles, CED and BNCT, each with the unique proficiency to overcome the mentioned challenges, present research. Recent years are seeing innovative combinatorial strategies to overcome the multifactorial resistance put forth by the GBM cell and its TME. This review discusses the contemporary and the investigational combinatorial strategies being employed to treat GBM and summarizes the evidence accumulated till date.

Glioblastoma is a form of brain tumor which typically leads to death in almost all patients. Over the last two decades, traditional treatment strategies such as surgery, radiotherapy and chemotherapy have been combined as standard therapy. Together, these aggressive treatment strategies have provided modest survival benefit with acceptable toxicity. However, relapse is the invariable norm resulting in death in the overwhelming majority of patients. Relapse occurs due to multiple factors such as inability of drugs to cross blood­brain barrier, immunosuppressive tumor microenvironment, stemness nature of glioma cells, tumor heterogeneity and enhanced hypoxia and angiogenic factors. Therefore, there is an urgent need to develop an innovative treatment approach to treat glioblastoma. Recently, several treatment strategies known as immunotherapies including CAR T cell therapy, dendritic cell vaccines, immune checkpoints blockade and oncolytic virus, nano particles and gene editing/silencing technology have demonstrated promising results in preclinical and few clinical trials. Furthermore, to increase the efficacy of these novel strategies, combinatorial approaches are being implemented for the treatment. This includes CAR T cell therapy in combination with small molecules, immune checkpoint inhibitors and oncolytic virus and nanoparticles plus gene editing, silencing or immune checkpoints inhibitors. These treatments have shown exciting results in preclinical settings and few of these trials are in progress. The review summarizes these combinatorial novel approaches and discusses them in detail.

Immunogenicity of CAR-T Cell Therapeutics: Evidence, Mechanism and Mitigation.

Chimeric antigen receptor T cell (CAR-T) therapy demonstrated remarkable success in long-term remission of cancers and other autoimmune diseases. Currently, six products (Kymriah, Yescarta, Tecartus, Breyanzi, Abecma, and Carvykti) are approved by the US-FDA for treatment of a few hematological malignancies. All the six products are autologous CAR-T cell therapies, where delivery of CAR, which comprises of scFv (single-chain variable fragment) derived from monoclonal antibodies for tumor target antigen recognition is through a lentiviral vector. Although available CAR-T therapies yielded impressive response rates in a large number of patients in comparison to conventional treatment strategies, there are potential challenges in the field which limit their efficacy. One of the major challenges is the induction of humoral and/or cellular immune response in patients elicited due to scFv domain of CAR construct, which is of non-human origin in majority of the commercially available products. Generation of anti-CAR antibodies may lead to the clearance of the therapeutic CAR-T cells, increasing the likelihood of tumor relapse and lower the CAR-T cells efficacy upon reinfusion. These immune responses influence CAR-T cell expansion and persistence, that might affect the overall clinical response. In this review, we will discuss the impact of immunogenicity of the CAR transgene on treatment outcomes. Finally, this review will highlight the mitigation strategies to limit the immunogenic potential of CARs and improve the therapeutic outcome.

IL-9 Abrogates the Metastatic Potential of Breast Cancer by Controlling Extracellular Matrix Remodeling and Cellular Contractility.

IL-9 is produced by Th9 cells and is classically known as a growth-promoting cytokine. Although protumorigenic functions of IL-9 are described in T cell lymphoma, recently, we and others have reported anti-tumor activities of IL-9 in melanoma mediated by mast cells and CD8+ T cells. However, involvement of IL-9 in invasive breast and cervical cancer remains unexplored. In this study, we demonstrate IL-9-dependent inhibition of metastasis of both human breast (MDA-MB-231 and MCF-7) and cervical (HeLa) tumor cells in physiological three-dimensional invasion assays. To dissect underlying mechanisms of IL-9-mediated suppression of invasion, we analyzed IL-9-dependent pathways of cancer cell metastasis, including proteolysis, contractility, and focal adhesion dynamics. IL-9 markedly blocked tumor cell-collagen degradation, highlighting the effects of IL-9 on extracellular matrix remodeling. Moreover, IL-9 significantly reduced phosphorylation of myosin L chain and resultant actomyosin contractility and also increased focal adhesion formation. Finally, IL-9 suppressed IL-17- and IFN-γ-induced metastasis of both human breast (MDA-MB-231) and cervical (HeLa) cancer cells. In conclusion, IL-9 inhibits the metastatic potential of breast and cervical cancer cells by controlling extracellular matrix remodeling and cellular contractility.

Robust Antitumor Activity and Low Cytokine Production by Novel Humanized Anti-CD19 CAR T Cells.

Recent studies have described the remarkable clinical outcome of anti-CD19 chimeric antigen receptor (CAR) T cells in treating B-cell malignancies. However, over 50% of patients develop life-threatening toxicities associated with cytokine release syndrome which may limit its utilization in low-resource settings. To mitigate the toxicity, we designed a novel humanized anti-CD19 CAR T cells by humanizing the framework region of single-chain variable fragment (scFv) derived from a murine FMC63 mAb and combining it with CD8α transmembrane domain, 4-1BB costimulatory domain, and CD3ζ signaling domain (h1CAR19-8BBζ). Docking studies followed by molecular dynamics simulation revealed that the humanized anti-CD19 scFv (h1CAR19) establishes higher binding affinity and has a flexible molecular structure with CD19 antigen compared with murine scFv (mCAR19). Ex vivo studies with CAR T cells generated from healthy donors and patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL) expressing either h1CAR19 or mCAR19 showed comparable antitumor activity and proliferation. More importantly, h1CAR19-8BBζ T cells produced lower levels of cytokines (IFNγ, TNFα) upon antigen encounter and reduced the induction of IL6 cytokine from monocytes than mCAR19-8BBζ T cells. There was a comparable proliferation of h1CAR19-8BBζ T cells and mCAR19-8BBζ T cells upon repeated antigen encounter. Finally, h1CAR19-8BBζ T cells efficiently eliminated NALM6 tumor cells in a preclinical model. In conclusion, the distinct structural modification in CAR design confers the novel humanized anti-CD19 CAR with a favorable balance of efficacy to toxicity providing a rationale to test this construct in a phase I trial.

The Th9 Axis Reduces the Oxidative Stress and Promotes the Survival of Malignant T Cells in Cutaneous T-Cell Lymphoma Patients.

Immune dysfunction is critical in pathogenesis of cutaneous T-cell lymphoma (CTCL). Few studies have reported abnormal cytokine profile and dysregulated T-cell functions during the onset and progression of certain types of lymphoma. However, the presence of IL9-producing Th9 cells and their role in tumor cell metabolism and survival remain unexplored. With this clinical study, we performed multidimensional blood endotyping of CTCL patients before and after standard photo/chemotherapy and revealed distinct immune hallmarks of the disease. Importantly, there was a higher frequency of "skin homing" Th9 cells in CTCL patients with early (T1 and T2) and advanced-stage disease (T3 and T4). However, advanced-stage CTCL patients had severely impaired frequency of skin-homing Th1 and Th17 cells, indicating attenuated immunity. Treatment of CTCL patients with standard photo/chemotherapy decreased the skin-homing Th9 cells and increased the Th1 and Th17 cells. Interestingly, T cells of CTCL patients express IL9 receptor (IL9R), and there was negligible IL9R expression on T cells of healthy donors. Mechanistically, IL9/IL9R interaction on CD3+ T cells of CTCL patients and Jurkat cells reduced oxidative stress, lactic acidosis, and apoptosis and ultimately increased their survival. In conclusion, coexpression of IL9 and IL9R on T cells in CTCL patients indicates the autocrine-positive feedback loop of Th9 axis in promoting the survival of malignant T cells by reducing the oxidative stress. IMPLICATIONS: The critical role of Th9 axis in CTCL pathogenesis indicates that strategies targeting Th9 cells might harbor significant potential in developing robust CTCL therapy.

Hydrogel scaffold with substrate elasticity mimicking physiological-niche promotes proliferation of functional keratinocytes.

High numbers of autologous human primary keratinocytes (HPKs) are required for patients with burns, wounds and for gene therapy of skin disorders. Although freshly isolated HPKs exhibit a robust regenerative capacity, traditional methodology fails to provide a sufficient number of cells. Here we demonstrated a well characterized, non-cytotoxic and inert hydrogel as a substrate that mimics skin elasticity, which can accelerate proliferation and generate higher numbers of HPKs compared to existing tissue culture plastic (TCP) dishes. More importantly, this novel method was independent of feeder layer or any exogenous pharmaceutical drug. The HPKs from the hydrogel-substrate were functional as demonstrated by wound-healing assay, and the expression of IFN-γ-responsive genes (CXCL10, HLADR). Importantly, gene delivery efficiency by a lentiviral based delivery system was significantly higher in HPKs cultured on hydrogels compared with TCP. In conclusion, our study provides the first evidence that cell-material mechanical interaction is enough to provide a rapid expansion of functional keratinocytes that might be used as autologous grafts for skin disorders.

Corrigendum: Lymphocytes in Cellular Therapy: Functional Regulation of CAR T Cells.

[This corrects the article DOI: 10.3389/fimmu.2018.03180.].

Differential Influence of IL-9 and IL-17 on Actin Cytoskeleton Regulates the Migration Potential of Human Keratinocytes.

T cells mediate skin immune surveillance by secreting specific cytokines and regulate numerous functions of keratinocytes, including migration during homeostasis and disease pathogenesis. Keratinocyte migration is mediated mainly by proteolytic cleavage of the extracellular matrix and/or by cytoskeleton reorganization. However, the cross-talk between T cell cytokines and actomyosin machinery of human primary keratinocytes (HPKs), which is required for cytoskeleton reorganization and subsequent migration, remains poorly examined. In this study, we describe that IL-9 profoundly reduced the actin stress fibers, inhibited contractility, and reduced the cortical stiffness of HPKs, which resulted in inhibition of the migration potential of HPKs in an adhesion- and MMP-independent manner. Similarly, IL-9 inhibited the IFN-γ-induced migration of HPKs by inhibiting the actomyosin machinery (actin stress fibers, contractility, and stiffness). IL-17A increased the actin stress fibers, promoted cellular contractility, and increased proteolytic collagen degradation, resulting in increased migration potential of HPKs. However, IL-9 inhibited the IL-17A-mediated HPKs migration. Mechanistically, IL-9 inhibited the IFN-γ- and IL-17A-induced phosphorylation of myosin L chain in HPKs, which is a major regulator of the actomyosin cytoskeleton. Finally, in addition to HPKs, IL-9 inhibited the migration of A-431 cells (epidermoid carcinoma cells) induced either by IFN-γ or IL-17A. In conclusion, our data demonstrate the influence of T cell cytokines in differentially regulating the actomyosin cytoskeleton and migration potential of human keratinocytes, which may have critical roles in skin homeostasis and pathogenesis of inflammatory diseases as well as skin malignancies.

Lymphocytes in Cellular Therapy: Functional Regulation of CAR T Cells.

Lymphocytes especially autologous T cells have been used for the treatment of numerous indications including cancers, autoimmune disorders and infectious diseases. Very recently, FDA approved Chimeric Antigen Receptor T cells (CAR T cells) therapy for relapse and refractory CD19+ B cell acute lymphoblastic leukemia (r/r B-ALL) and r/r diffuse large B cell lymphoma (r/r DLBCL) upon their remarkable success in multiple Phase I-II clinical trials. While CAR T cells are considered as major breakthrough in the field of cancer immunotherapy, the regulation of CAR T cells remains poorly understood. In this review we will discuss the strategies that regulate the CAR T cells efficacy and persistence with focus on roles of different structural component of CAR construct. Different domains of CAR construct, for example, antigen binding domain, hinge, transmembrane, and signaling domain as well as immune-regulatory cytokines have significant impact on CAR T cell efficacy. Finally, this review will highlight the strategies that will promote CAR T cells efficacy and will reduce the toxicity.