The RNA-binding protein Musashi 1 stabilizes the oncotachykinin 1 mRNA in breast cancer cells to promote cell growth.

Substance P and its truncated receptor exert oncogenic effects. The high production of substance P in breast cancer cells (BCCs) is caused by the enhancement of tachykinin (TAC)1 translation by cytosolic factor. In vitro translational studies and mRNA stabilization analyses indicate that BCCs contain the factor needed to increase TAC1 translation and to stabilize the mRNA. Prediction of protein folding, RNA-shift analysis, and proteomic analysis identified a 40 kDa molecule that interacts with the noncoding exon 7. Western blot analysis and RNA supershift identified Musashi 1 (Msi1) as the binding protein. Ectopic expression of TAC1 in nontumorigenic breast cells (BCs) indicates that TAC1 regulates its stability by increasing Msi1. Using a reporter gene system, we showed that Msi1 competes with microRNA (miR)130a and -206 for the 3' UTR of exon 7/TAC1. In the absence of Msi1 and miR130a and -206, reporter gene activity decreased, indicating that Msi1 expression limits TAC1 expression. Tumor growth was significantly decreased when nude BALB/c mice were injected with Msi1-knockdown BCCs. In summary, the RNA-binding protein Msi1 competes with miR130a and -206 for interaction with TAC1 mRNA, to stabilize and increase its translation. Consequently, these interactions increase tumor growth.

Outpatient administration of CAR T-cell therapy: a focused review with recommendations for implementation in community based centers.

Chimeric Antigen Receptor T-cell (CAR-T) therapy has transformed the treatment landscape for hematological malignancies, showing high efficacy in patients with relapsed or refractory (R/R) disease and otherwise poor prognosis in the pre-CAR-T era. These therapies have been usually administered in the inpatient setting due to the risk of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). However, there is a growing interest in the transition to outpatient administration due to multiple reasons. We review available evidence regarding safety and feasibility of outpatient administration of CD19 targeted and BCMA targeted CAR T-cell therapy with an emphasis on the implementation of outpatient CAR-T programs in community-based centers.

Increased expression of musashi 1 on breast cancer cells has implication to understand dormancy and survival in bone marrow.

Breast cancer (BC) stem cells (CSCs) resist treatment and can exist as dormant cells in tissues such as the bone marrow (BM). Years before clinical diagnosis, BC cells (BCCs) could migrate from the primary site where the BM niche cells facilitate dedifferentiation into CSCs. Additionally, dedifferentiation could occur by cell autonomous methods. Here we studied the role of Msi 1, a RNA-binding protein, Musashi I (Msi 1). We also analyzed its relationship with the T-cell inhibitory molecule programmed death-ligand 1 (PD-L1) in CSCs. PD-L1 is an immune checkpoint that is a target in immune therapy for cancers. Msi 1 can support BCC growth through stabilization of oncogenic transcripts and modulation of stem cell-related gene expression. We reported on a role for Msi 1 to maintain CSCs. This seemed to occur by the differentiation of CSCs to more matured BCCs. This correlated with increased transition from cycling quiescence and reduced expression of stem cell-linked genes. CSCs co-expressed Msi 1 and PD-L1. Msi 1 knockdown led to a significant decrease in CSCs with undetectable PD-L1. This study has implications for Msi 1 as a therapeutic target, in combination with immune checkpoint inhibitor. Such treatment could also prevent dedifferentiation of breast cancer to CSCs, and to reverse tumor dormancy. The proposed combined treatment might be appropriate for other solid tumors.

Incidence and risk factors associated with a syndrome of persistent cytopenias after CAR-T cell therapy (PCTT).

Anti-CD19 Chimeric Antigen Receptor T cells (CAR-T) have shown dramatic efficacy in treating refractory aggressive B cell Lymphomas leading to FDA approval of axicabtagene ciloleucel and tisagenlecleucel. While long-term remission rate for both is higher than 33%, this treatment is associated with life-threatening complications including cytokine-release syndrome, encephalopathy, and lethal cerebral edema. Here we describe a case series of bone marrow failure syndromes with or without co-existing clonal myelodysplastic syndrome. Bone marrow failure was defined as absolute neutrophil count (ANC) <500 neutrophils/µL day 42 after infusion of CAR-T cells or filgrastim support to reach that number. We use "persistent cytopenias after T-cell therapy (PCTT)" to describe this syndrome which has an incidence of 38% with axicabtagene ciloleucel. Platelets <75,000/µL at the time of initiation of lymphodepleting chemotherapy and occurrence of maximum severity of cytokine-release syndrome (CRS) on day 0 or 1 after infusion of CAR-T cells are independent predictors of PCTT.

Chimeric antigen receptor T cells, a savior with a high price.

Chimeric antigen receptor (CAR) T cells represent a medical and scientific breakthrough that may represent a paradigm for the future of personalized medicine in the age of cancer immunotherapy. As with many new cancer agents, such novel and incredible results come with a high price. At the time of the writing of this article, there are two CAR T cells available, Kymriah, produced by Novrtis with a price tag of US$475,000 and Yescarta produced by Gilead Pharmaceuticals with a price tag of US$373,000, neither price including the required hospital admission in order to administer the agent in addition to potential treatment of side effects. There are several issues that are imperative to recognize when understanding the high cost, however the two more pertinent issues are low availability of the agent and no billing code. While only approved for less than a year, there are thoughts about how to bring the price down with more approved CAR T cells and more center with the ability to administer this therapy, however results may be years away before they are realized. In the short term, insurance companies are grappling over how to pay for CAR T therapy, with one of the biggest voids concerning the absence of a billing code for CAR T cells. Regardless, its high price tag highlights moral issues underlying value-based payments and whether the treatment is worth the cost while evaluating the juxtaposition of life years and monetary values. As CAR T cells expand the boundaries of immunotherapy with extraordinary results, the need for a lower price in combination for more availability of CAR T cells will grow until some of these fundamental issues are addressed.

A Perspective of Immunotherapy for Breast Cancer: Lessons Learned and Forward Directions for All Cancers.

Immunotherapy for cancer has been a focus 50 years ago. At the time, this treatment was developed prior to cloning of the cytokines, no knowledge of regulatory T-cells, and very little information that mesenchymal stem cells (MSCs) (originally colony forming unit-fibroblasts [CFU-F]) could be licensed by the inflammatory microenvironment to suppress an immune response. Given the information available at that time, mononuclear cells from the peripheral blood were activated ex vivo and then replaced in the patients with tumor. The intent was to harness these activated immune cells to target the cancer cells. These studies did not lead to long-term responses because the activated cells when reinfused into the patients were an advantage to the resident MSCs, which can home the tumor and then become suppressive in the presence of the immune cells. The immune suppression caused by MSCs would also expand regulatory T-cells, resulting instead in tumor protection. As time progressed, these different fields converged into a new approach to use immunotherapy for cancer. This article discusses these approaches and also reviews chimeric antigen receptor in the context of future treatments for solid tumors, including breast cancer.

Stem cell in alternative treatments for brain tumors: potential for gene delivery.

Despite ongoing research efforts and attempts to bring new drugs into trial, the prognosis for brain tumors remains poor. Patients with the most common and lethal intracranial neoplasia, glioblastoma multiforme (GBM), have an average survival of one year with combination of surgical resection, radiotherapy and temozolomide. One of the main problems in the treatment of GBM is getting drugs across the blood brain barrier (BBB) efficiently. In an attempt to solve this problem, there are ongoing experimental and clinical trials to deliver drugs within stem cells. The purpose for this method is the ease by which stem cells home to the brain. This review discusses the experimental and clinical applications of stem cells for GBM. We also discuss the different properties of stem cells. This information is important to understand why one stem cell would be advantageous over another in cell therapy. We provide an overview of the different drug delivery methods, gene-based treatments and cancer vaccines for GBM, including the stem cell subset.

Cancer immunotherapy: accomplishments to date and future promise.

Cancer remains a devastating disease as existing therapies are too often ineffective and toxicities remain unacceptably high. Immunotherapies for cancer offer the promise of the specificity and memory of the immune system against malignant cells to achieve durable cure with minimal toxicity. Beginning with the success of bone marrow transplantation for blood-borne cancers, and the more recent development of monoclonal antibody therapeutics for a variety of tumors, immunotherapies are already among the most successful class of treatments for cancer. Greater understanding of immunoregulatory mechanisms and improved techniques for immune cell manipulation and engineering have led to new immunomodulatory approaches and cell-based therapies for cancer that have generated great excitement within the biomedical community. As these technologies continue to improve, and as new approaches for harnessing the power and specificity of the immune system are developed, immunotherapies will play an increasingly important role in the treatment of cancer. Here, we review the history of immunotherapies for cancer and discuss existing and emerging immunotherapy technologies that hope to translate the promise of immunotherapy into clinical reality.

Can breast cancer stem cells evade the immune system?

The evidence seems to be growing in favor of the stem cell theory of cancer with the emergence of studies demonstrating the parallel mechanisms of self renewing pathways in stem cells and particular subsets of cancer cells. The finding of leukemia stem cells and subsequently breast cancer stem cells (BCSC) further supports the concept. The importance of these findings lends itself to the selfrenewal properties of stem cells in addition to the survival characteristics of stem cells, mechanisms that will have to be overcome when creating treatment modalities. In particular, research has shown that stem cells and a specific type of stem cells, mesenchymal stem cells (MSC), have special drug effluxing properties and some interactions with particular cells of the immune system that may serve major roles in immunosuppresion and overall tumor cell survival. Furthermore, the recent discovery of epithelial to mesenchymal transition (EMT) has laid out a possible mechanism for tumor cells to lose particular phenotypic epithelial cell markers and gain phenotypic mesenchymal cell markers. This process is implicated in metastasis in addition to overall tumor survival and evasion of the immune system. This review examines the current understanding of how tumor cells evade the immune system, but will first explore stem cells, cancer stem cells, normal immune interaction with tumor cells, and EMT.