CNOT3 targets negative cell cycle regulators in non-small cell lung cancer development

Lung cancer is one of the major causes of cancer death and clarification of its molecular pathology is highly prioritized. The physiological importance of mRNA degradation through the CCR4-NOT deadenylase has recently been highlighted. For example, mutation in CNOT3, a gene coding for CNOT3 subunit of the CCR4-NOT complex, is found to be associated with T-cell acute lymphoblastic leukemia, T-ALL, though its contribution to other cancers has not been reported. Here, we provide evidence suggesting that CNOT3 is required for the growth of non-small cell lung cancer. Depletion of CNOT3 suppresses proliferation of A549 human non-small cell lung cancer cells with enhanced mRNA stability and subsequent elevated expression of p21. In addition, we identified the mRNA for Kruppel-like factor 2 transcription factor, an inducer of p21, as a novel mRNA degradation target of CNOT3 in non-small cell lung cancer cells. Aberrant up-regulation of Kruppel-like factor 2 by CNOT3 depletion leads to impairment in the proliferation of A549 cells. Consistent with these findings, elevated mRNA expression of CNOT3 in non-small cell lung cancer in comparison with the paired normal lung epithelium was confirmed through scrutinization of the RNA-sequencing datasets from The Cancer Genome Atlas. Moreover, we found an inverse correlation between CNOT3 and CDKN1A (encoding p21) mRNA expression using the combined datasets of normal lung epithelium and non-small cell lung cancer. Thus, we propose that the up-regulation of CNOT3 facilitates the development of non-small cell lung cancer through down-regulation of Kruppel-like factor 2 and p21, contrary to tumor suppressive functions of CNOT3 in T-ALL

WT1 Peptide Cancer Vaccine for Patients with Hematopoietic Malignancies and Solid Cancers

Wild-type Wilms' tumor gene WT1 is expressed at a high level in hematopoietic malignancies including acute leukemia, chronic myelogenous leukemia, and myelodysplastic syndromes, as well as in various kinds of solid cancers. Human cytotoxic T lymphocytes (CTLs), which could specifically lyse WT1-expressing tumor cells with HLA class I restriction, were generated in vitro. It was also demonstrated that mice immunized with the WT1 peptide rejected challenges by WT1-expressing cancer cells and survived with no signs of autoaggression to normal organs that physiologically expressed WT1. Furthermore, we and others detected IgM and IgG WT1 antibodies in patients with hematopoietic malignancies, indicating that the WT1 protein was highly immunogenic, and that immunoglobulin class-switch-inducing, WT1-specific, cellular immune responses were elicited in these patients. CD8+ WT1-specific CTLs were also detected in peripheral blood or tumor-draining lymph nodes of cancer patients. These results provided us with the rationale for elicitation of CTL responses targeting the WT1 product for cancer immunotherapy. On the basis of these findings, we performed a phase I clinical trial of a WT1 peptide cancer vaccine for the patients with malignant neoplasms. These results strongly suggested that the WT1 peptide cancer vaccine had efficacy in the clinical setting because clinical responses, including reduction of leukemic blast cells or regression of tumor masses, were observed after the WT1 vaccination in patients with hematopoietic malignancies or solid cancers. The power of a tumor-associated-antigen (TAA)-derived cancer vaccine may be enhanced in combination with stronger adjuvants, helper peptide, molecular-target-based drugs, or some chemotherapy drugs, such as gemcitabine, which has been revealed to suppress regulartory T-cell function. In contrast, reduction of WT1 peptide dose may be needed for the treatment of patients with hematological stem cell diseases, because rapid and strong destruction of malignant cell-sustained hematopoiesis before recovery of normal hematopoiesis may lead to pancytopenia in these patients

Erythropoietin modulation of podocalyxin and a proposed erythroblast niche

Epo's erythropoietic capacity is ascribed largely to its antiapoptotic actions. In part via gene profiling of bone marrow erythroblasts, Epo is now shown to selectively down-modulate the adhesion/migration factors chemokine receptor-4 (Cxcr4) and integrin alpha-4 (Itga4) and to up-modulate growth differentiation factor-3 (Gdf3), oncostatin-M (OncoM), and podocalyxin like-1 (PODXL). For PODXL, Epo dose–dependent expression of this CD34-related sialomucin was discovered in Kit+CD71high proerythroblasts and was sustained at subsequent Kit−CD71high and Ter119+ stages. In vivo, Epo markedly induced PODXL expression in these progenitors and in marrow-resident reticulocytes. This was further associated with a rapid release of PODXL+ reticulocytes to blood. As studied in erythroblasts expressing minimal Epo receptor (EpoR) alleles, efficient PODXL induction proved dependence on an EpoR-PY343 Stat5 binding site. Moreover, in mice expressing an EpoR-HM F343 allele, compromised Epo-induced PODXL expression correlated with abnormal anucleated red cell representation in marrow. By modulating this select set of cell-surface adhesion molecules and chemokines, Epo is proposed to mobilize erythroblasts from a hypothesized stromal niche and possibly promote reticulocyte egress to blood