Jocelyn Reader

Multiple myeloma patients with CKS1B gene amplification have a shorter progression-free survival post-autologous stem cell transplantation

The prevalence and prognostic relevance of recurrent gains of CKS1B (cyclin kinase subunit 1B) gene at chromosome 1q21 region was investigated by interphase fluorescence in situ hybridisation in a cohort of 99 multiple myeloma (MM) patients treated with intensive chemotherapy followed by autologous stem cell transplantation. CKS1B amplification (3–8 CKS1B signals) was detected in 31of 99 (31%) patients and was associated with deletions of p53 (P = 0·003) and 13q (P = 0·039) but not with translocation t(11;14) or t(4;14). CKS1B amplification was associated with bone marrow plasmacytosis (P = 0·02), but there was no correlation with patient age, gender, disease stage, lytic bone lesions, albumin, creatinine, C‐reactive protein or beta‐2 microglobulin levels. Patients with CKS1B amplification had a significantly shorter progression‐free survival than those without such amplification (18·5 vs. 25·7 months, P = 0·035). Likewise, a shorter overall survival (44·8 months vs. not reached) was observed; however, the difference did not reach statistical significance (P = 0·20). Seven patients had paired bone marrows obtained at diagnosis and at relapse, the percentage of cells with CKS1B amplification and the level of amplification were significantly increased in the relapse marrows. In this cohort of patients, CKS1B was frequently amplified in MM and may represent genetic instability associated with disease progression.

Prostaglandin E2 EP receptors as therapeutic targets in breast cancer.

Prostaglandins are lipid compounds that mediate many physiological effects. Prostaglandin E2 (PGE2) is the most abundant prostanoid in the human body, and synthesis of PGE2 is driven by cyclooxygenase enzymes including COX-2. Both elevated expression of COX-2 and increased PGE2 levels have been associated with many cancers including breast cancer. PGE2 exerts its effect by binding to the E series of prostaglandin receptors (EP) which are G protein-coupled receptors. Four EP receptor subtypes exist, EP1–4, and each is coupled to different intracellular signaling pathways. As downstream effectors of the COX-2 pathway, EP receptors have been shown to play a role in breast and other malignancies and in cancer metastasis. The role of each EP receptor in malignant behavior is complex and involves the interplay of EP receptor signaling on the tumor cell, on stromal cells, and on host immune effector cells. While preclinical and epidemiological data support the use of nonsteroidal anti-inflammatory drugs and selective COX-2 inhibitors (COXibs) for the prevention and treatment of malignancy, toxicities due to COXibs as well as less than promising results from clinical trials have laboratories seeking alternative targets. As knowledge concerning the role of EP receptors in cancer grows, so does the potential for exploiting EP receptors as therapeutic targets for the treatment or prevention of cancer and cancer metastasis.

A novel NUP98-PHF23 fusion resulting from a cryptic translocation t(11;17)(p15;p13) in acute myeloid leukemia.

A novel NUP98-PHF23 fusion resulting from a cryptic translocation t(11;17)(p15;p13) in acute myeloid leukemia

A prostaglandin E (PGE) receptor EP4 antagonist protects natural killer cells from PGE2-mediated immunosuppression and inhibits breast cancer metastasis

Cyclooxygenase-2 is frequently upregulated in epithelial tumors and contributes to poor outcomes in multiple malignancies. The COX-2 product prostaglandin E2 (PGE2) promotes tumor growth and metastasis by acting on a family of four G protein-coupled receptors (EP1–4). Using a novel small molecule EP4 antagonist (RQ-15986) and a syngeneic murine model of metastatic breast cancer, we determined the effect of EP4 blockade on innate immunity and tumor biology. Natural killer (NK)-cell functions are markedly depressed in mice bearing murine mammary tumor 66.1 or 410.4 cells owing to the actions of PGE2 on NK cell EP4 receptors. The EP4 agonist PGE1-OH inhibits NK functions in vitro, and this negative regulation is blocked by RQ-15986. Likewise, the treatment of tumor-bearing mice with RQ-15986 completely protected NK cells from the immunosuppressive effects of the tumor microenvironment in vivo. RQ-15986 also has direct effects on EP4 expressed by tumor cells, inhibiting the PGE2-mediated activation of adenylate cyclase and blocking PGE2-induced tumor cell migration. The pretreatment of tumor cells with a non-cytotoxic concentration of RQ-15986 inhibited lung colonization, a beneficial effect that was lost in mice depleted of NK cells. The oral administration of RQ-15986 inhibited the growth of tumor cells implanted into mammary glands and their spontaneous metastatic colonization to the lungs, resulting in improved survival. Our findings reveal that EP4 antagonism prevents tumor-mediated NK-cell immunosuppression and demonstrates the anti-metastatic activity of a novel EP4 antagonist. These observations support the investigation of EP4 antagonists in clinical trials.

Prostaglandin E receptor EP4 is a therapeutic target in breast cancer cells with stem-like properties

The cyclooxygenase pathway is strongly implicated in breast cancer progression but the role of this pathway in the biology of breast cancer stem/progenitor cells has not been defined. Recent attention has focused on targeting the cyclooxygenase 2 (COX-2) pathway downstream of the COX-2 enzyme by blocking the activities of individual prostaglandin E (EP) receptors. Prostaglandin E receptor 4 (EP4) is widely expressed in primary invasive ductal carcinomas of the breast and antagonizing this receptor with small molecule inhibitors or shRNA directed to EP4 inhibits metastatic potential in both syngeneic and xenograft models. Breast cancer stem/progenitor cells are defined as a subpopulation of cells that drive tumor growth, metastasis, treatment resistance, and relapse. Mammosphere-forming breast cancer cells of human (MDA-MB-231, SKBR3) or murine (66.1, 410.4) origin of basal-type, Her-2 phenotype and/or with heightened metastatic capacity upregulate expression of both EP4 and COX-2 and are more tumorigenic compared to the bulk population. In contrast, luminal-type or non-metastatic counterparts (MCF7, 410, 67) do not increase COX-2 and EP4 expression in mammosphere culture. Treatment of mammosphere-forming cells with EP4 inhibitors (RQ-15986, AH23848, Frondoside A) or EP4 gene silencing, but not with a COX inhibitor (Indomethacin) reduces both mammosphere-forming capacity and the expression of phenotypic markers (CD44hi/CD24low, aldehyde dehydrogenase) of breast cancer stem cells. Finally, an orally delivered EP4 antagonist (RQ-08) reduces the tumor-initiating capacity and markedly inhibits both the size of tumors arising from transplantation of mammosphere-forming cells and phenotypic markers of stem cells in vivo. These studies support the continued investigation of EP4 as a potential therapeutic target and provide new insight regarding the role of EP4 in supporting a breast cancer stem cell/tumor-initiating phenotype.

Prostaglandin E Receptor EP1 Suppresses Breast Cancer Metastasis and Is Linked to Survival Differences and Cancer Disparities

Cyclooxygenase-2 is frequently overexpressed and associated with poor prognosis in breast cancer. The cyclooxygenase-2 product prostaglandin E2 elicits cellular responses through four G-protein–coupled receptors, designated EP1 to EP4, coupled to distinct intracellular signaling pathways. EP4, expressed on malignant breast cells, promotes metastasis; however, a role for EP1 in metastasis has not been investigated. Using a murine model of metastatic breast cancer, we now show that pharmacologic antagonism of EP1 with SC19220 or AH6809 promoted lung colonization of mammary tumor cells by 3.7- to 5.4-fold. Likewise, reducing EP1 gene expression by shRNA also increased metastatic capacity relative to cells transfected with nonsilencing vector but did not affect the size of transplanted tumors. Examination of invasive ductal carcinomas by immunohistochemistry shows that EP1 was detected in both the cytoplasm and nucleus of benign ducts as well as malignant cells in some samples, but was absent or limited to either the nucleus or cytoplasm in other malignant samples. Overall survival for women with tumors that were negative for nuclear EP1 was significantly worse than for women with EP1 expression (P = 0.008). There was no difference in survival for women with differences in cytoplasmic EP1 expression (P = 0.46). Comparing EP1 mRNA in breast tumors from African American and European American women revealed that many more African American breast tumors lacked detectable EP1 mRNA (P = 0.04). These studies support the hypothesis that EP1 functions as a metastasis suppressor and that loss of nuclear EP1 is associated with poorer overall survival and may contribute to disparities in outcome in different populations. Mol Cancer Res; 8(10); 1310–8. ©2010 AACR.

Activation of a novel palmitoyltransferase ZDHHC14 in acute biphenotypic leukemia and subsets of acute myeloid leukemia.

Activation of a novel palmitoyltransferase ZDHHC14 in acute biphenotypic leukemia and subsets of acute myeloid leukemia

Analysis of 6q deletion in Waldenstrom macroglobulinemia

The frequency and prognostic significance of chromosome 6q deletion were investigated in a cohort of patients with Waldenstrom macroglobulinemia (WM). By interphase cytoplasmic fluorescence in situ hybridization with probes for 6q21 and 6q25, we detected hemizygous 6q deletions in the clonal lymphoplasmacytic cells in 13 (38%) out of 34 patients. Patients with 6q deletions had a lower IgM paraprotein levels than non‐deleted patients (P = 0.04). There was no correlation between 6q deletion and other clinical features of WM. There was no significant difference in overall survival between 6q deleted and non‐6q deleted groups (P = 0.92). Our study confirms that 6q deletion is a frequent event, but it does not appear to be a prognostic marker for patients with WM.

Divergent roles of CXCR3 isoforms in promoting cancer stem-like cell survival and metastasis

AbstractThere is growing evidence that several chemokine receptors including CXCR3 contribute to metastasis of breast and other cancers, however, in order to target CXCR3 effectively, it is critical to understand the relative contribution of each CXCR3 isoform. Furthermore, the possible contribution of either major CXCR3 isoform (CXCR3-A, CXCR3-B) to cancer stem cell behavior has not been reported. We employed primary invasive ductal carcinomas, a panel of breast cell lines, and a xenograft model of metastatic breast cancer to examine the role of CXCR3 isoforms in the behavior of breast cancer stem-like cells and the contribution of each isoform to metastasis. In primary human breast cancer specimens as well as established breast cancer cell lines, CXCR3-A is more highly expressed than CXCR3-B. Conversely, immortalized normal MCF10A cells express more CXCR3-B relative to CXCR3-A. Overexpression of CXCR3-B in MDA-MB-231 basal-like cells inhibits CXCR3 ligand-stimulated proliferation, which is accompanied by reduced ligand-mediated activation of ERK1/2 and p38 kinases. Likewise, metastatic capacity is reduced in vivo by higher levels of CXCR3-B, and migratory and invasive properties are inhibited in vitro; conversely, silencing of CXCR3-B enhances lung colonization. In contrast to the anti-metastatic and anti-proliferative roles of CXCR3-B in the non-stem cell population, this isoform supports a cancer stem-like cell phenotype. CXCR3-B is markedly elevated in mammosphere-forming parental cells and overexpressing CXCR3-B further enhances mammosphere-forming potential as well as growth in soft agar; stem-like behavior is inhibited in MDA-MB-231shCXCR3-B cells. Targeting of both CXCR3 isoforms may be important to block the stem cell-promoting actions of CXCR3-B, while inhibiting the pro-proliferative and metastasis-promoting functions of CXCR3-A.

REL -positive double minute chromosomes in follicular lymphoma

H4/D10S170 proteins is the coiled-coil domain, which contributes with its dimerization/activation moiety to building tyrosine kinase fusion proteins. Given these findings, a double color double fusion FISH assay with clone CTD-2601I11 encompassing the PDGFRB breakpoint, and clone RP11-205M9 for TPM3 (Figure 2) is a valid diagnostic test for discriminating between t(1;5)(q21;q33)/ TPM3/PDGFRB, as described in the present letter, and t(1;5) involving other genes at 1q21–q23 such as PDE4DIP-PDGFRB, which has been reported in a pediatric case of chronic myeloproliferative disorder.