Regulatory T (Treg) cell infiltration of solid tumors often correlates with poor prognosis, but their tumor-suppressive function lacks mechanistic understanding. Through a combination of transgenic mice, cell fate mapping, adoptive transfer, and co-injection strategies, we demonstrate that Treg cell ablation-dependent anti-tumor effects in murine breast cancer require intratumoral recruitment of CCR2 inflammatory monocytes, which primarily differentiate into tumor-associated macrophages (TAMs), and lead to reprogramming of their function in an IFN-γ-dependent manner. Furthermore, transcriptomic signatures from murine TAMs in Treg cell-ablated conditions correlate with increased overall survival in human breast cancer.
View Article and Find Full Text PDFThe sphingolipid ceramide 1-phosphate (C1P) directly binds to and activates group IVA cytosolic phospholipase A (cPLAα) to stimulate the production of eicosanoids. Because eicosanoids are important in wound healing, we examined the repair of skin wounds in knockout (KO) mice lacking cPLAα and in knock-in (KI) mice in which endogenous cPLAα was replaced with a mutant form having an ablated C1P interaction site. Wound closure rate was not affected in the KO or KI mice, but wound maturation was enhanced in the KI mice compared to that in wild-type controls.
View Article and Find Full Text PDFTriple negative breast cancer (TNBC) has an unusually low 5-year survival rate linked to higher metastatic rates. Our laboratory recently delineated a role for the alternative RNA splicing (AS) of cytoplasmic polyadenylation element binding protein 2 (CPEB2), via inclusion/exclusion of exon 4, in the metastasis of TNBC. In these studies, the mechanism governing the inclusion/exclusion of exon 4 was examined.
View Article and Find Full Text PDFMultidrug resistance (MDR) represents a major hindrance to the efficacy of cancer chemotherapeutics. While surgical resection, radiation, and chemotherapy can be used to reduce tumor size, the subsequent appearance of drug resistant cells is a frequent problem. One of the main contributors to the development of MDR is increased expression of multi-drug resistant protein 1 (MDR1), also known as P-glycoprotein (P-gp).
View Article and Find Full Text PDFThe translational regulator cytosolic polyadenylation element-binding protein 2 (CPEB2) has two isoforms, CPEB2A and CPEB2B, derived by alternative splicing of RNA into a mature form that either includes or excludes exon 4. Previously, we reported that this splicing event is highly dysregulated in aggressive forms of breast cancers, which overexpress CPEB2B. The loss of CPEB2A with a concomitant increase in CPEB2B was also required for breast cancer cells to resist cell death because of detachment (anoikis resistance) and metastasize To examine the mechanism by which CPEB2 isoforms mediate opposing effects on cancer-related phenotypes, we used next generation sequencing of triple negative breast cancer cells in which the isoforms were specifically down-regulated.
View Article and Find Full Text PDFUnlabelled: Despite a recent shift away from anti-insulin-like growth factor I receptor (IGF-IR) therapy, this target has been identified as a key player in the resistance mechanisms to various conventional and targeted agents, emphasizing its value as a therapy, provided that it is used in the right patient population. Molecular markers predictive of antitumor activity of IGF-IR inhibitors remain largely unidentified. The aim of this study is to evaluate the impact of insulin receptor (IR) isoforms on the antitumor efficacy of cixutumumab, a humanized mAb against IGF-IR, and to correlate their expression with therapeutic outcome.
View Article and Find Full Text PDFStem cell factor receptor (c-Kit) exerts multiple biological effects on target cells upon binding its ligand stem cell factor (SCF). Aberrant activation of c-Kit results in dysregulated signaling and is implicated in the pathogenesis of numerous cancers. The development of more specific and effective c-Kit therapies is warranted given its essential role in tumorigenesis.
View Article and Find Full Text PDFCancer Biol Ther
October 2009
Although most researchers in biology tend to focus on very specific issues and questions about their preferred gene or pathway, sometimes we face situations in which nature presents us with a remarkable example of a gene with multiple functions. Since the discovery of the early growth response 1 (EGR1) gene in the mid eighties, several independent groups attributed its activation as an immediate early response gene to extracellular stimuli such as environmental cues, growth factors, irradiation and small molecules. Even twenty-plus years after its initial cloning and characterization, EGR1 continues to attract considerable attention among biological circles.
View Article and Find Full Text PDFComp Biochem Physiol Part D Genomics Proteomics
June 2006
Creatine kinase (CK) catalyzes the reversible transfer of thegamma-terminal phosphate of MgATP to the guanidine creatine (Cr) forming MgADP and phosphocreatine (PCr). The CK reaction plays a central role in both temporal and spatial ATP buffering in cells displaying high and variable rates of ATP turnover. There is a constant non-enzymatic conversion of Cr and PCr to creatinine that must be compensated for by biosynthesis and/or dietary uptake.
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