Targeted protein degradation of PDE4 shortforms by a novel proteolysis targeting chimera.

Cyclic AMP (cAMP) has a crucial role in many vital cellular processes and there has been much effort expended in the discovery of inhibitors against the enzyme superfamily that degrades this second messenger, namely phosphodiesterases (PDEs). The journey of competitive PDE inhibitors to the clinic has been hampered by side effects profiles that have resulted from a lack of selectivity for subfamilies and individual isoforms because of high conservation of catalytic site sequences and structures. Here we introduce a proteolysis targeting chimera (PROTAC) that can specifically target a small subset of isoforms from the PDE4 family to send the enzyme for degradation at the proteasome by recruiting a ubiquitin E3 ligase into proximity with the PDE.

A novel fibroblast activation inhibitor attenuates left ventricular remodeling and preserves cardiac function in heart failure.

Cardiac fibroblasts are critical mediators of fibrotic remodeling in the failing heart and transform into myofibroblasts in the presence of profibrotic factors such as transforming growth factor-β. Myocardial fibrosis worsens cardiac function, accelerating the progression to decompensated heart failure (HF). We investigated the effects of a novel inhibitor (NM922; NovoMedix, San Diego, CA) of the conversion of normal fibroblasts to the myofibroblast phenotype in the setting of pressure overload-induced HF.

Structure of the human Cereblon-DDB1-lenalidomide complex reveals basis for responsiveness to thalidomide analogs.

The Cul4-Rbx1-DDB1-Cereblon E3 ubiquitin ligase complex is the target of thalidomide, lenalidomide and pomalidomide, therapeutically important drugs for multiple myeloma and other B-cell malignancies. These drugs directly bind Cereblon (CRBN) and promote the recruitment of substrates Ikaros (IKZF1) and Aiolos (IKZF3) to the E3 complex, thus leading to substrate ubiquitination and degradation. Here we present the crystal structure of human CRBN bound to DDB1 and the drug lenalidomide.

Isosteric analogs of lenalidomide and pomalidomide: synthesis and biological activity.

A series of analogs of the immunomodulary drugs lenalidomide (1) and pomalidomide (2), in which the amino group is replaced with various isosteres, was prepared and assayed for immunomodulatory activity and activity against cancer cell lines. The 4-methyl and 4-chloro analogs 4 and 15, respectively, displayed potent inhibition of tumor necrosis factor-α (TNF-α) in LPS-stimulated hPBMC, potent stimulation of IL-2 in a human T cell co-stimulation assay, and anti-proliferative activity against the Namalwa lymphoma cell line. Both of these analogs displayed oral bioavailability in rat.

Pomalidomide augments fetal hemoglobin production without the myelosuppressive effects of hydroxyurea in transgenic sickle cell mice.

Pharmacologic induction of fetal hemoglobin (HbF) expression is an effective treatment strategy for sickle cell disease (SCD) and β-thalassemia. Pomalidomide is a potent structural analog of thalidomide and member of a new class of immunomodulatory drugs. Recent reports demonstrated that pomalidomide reduced or eliminated transfusion requirements in certain hematologic malignancies and induced HbF ex vivo in CD34(+) progenitor cells from healthy and SCD donors.

Immunomodulatory drugs reorganize cytoskeleton by modulating Rho GTPases.

IMiDs immunomodulatory drugs, including lenalidomide and pomalidomide represent a novel class of small molecule anticancer and anti-inflammatory drugs with broad biologic activities. However, the molecular mechanism through which these drugs exert their effects is largely undefined. Using pomalidomide and primary human monocytes, we report that pomalidomide rapidly and selectively activated RhoA and Rac1, but not Cdc42 or Ras, in the absence of any costimulation.

Discovery of (S)-N-[2-[1-(3-ethoxy-4-methoxyphenyl)-2-methanesulfonylethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl] acetamide (apremilast), a potent and orally active phosphodiesterase 4 and tumor necrosis factor-alpha inhibitor.

In this communication, we report the discovery of 1S (apremilast), a novel potent and orally active phosphodiesterase 4 (PDE4) and tumor necrosis factor-alpha inhibitor. The optimization of previously reported 3-(1,3-dioxo-1,3-dihydroisoindol-2-yl)-3-(3,4-dimethoxyphenyl)propionic acid PDE4 inhibitors led to this series of sulfone analogues. Evaluation of the structure-activity relationship of substitutions on the phthalimide group led to the discovery of an acetylamino analogue 1S, which is currently in clinical trials.

Immunomodulatory drugs Revlimid (lenalidomide) and CC-4047 induce apoptosis of both hematological and solid tumor cells through NK cell activation.

Revlimid (Lenalidomide, CC-5013) and CC-4047 are IMiDs immunomodulatory drugs that have been described as having immunomodulatory properties and anti-tumor activity. Here we report proapoptotic effects of CC-5013 and CC-4047 on tumor cells in a co-culture model of PBMC and tumor cells. CC-5013 and CC-4047 enhanced PBMC activity leading to tumor cell apoptosis in K562/PBMC co-culture model.

Targeting the p27 E3 ligase SCF(Skp2) results in p27- and Skp2-mediated cell-cycle arrest and activation of autophagy.

Decreased p27(Kip1) levels are a poor prognostic factor in many malignancies, and can occur through up-regulation of SCF(Skp2) E3 ligase function, resulting in enhanced p27 ubiquitination and proteasome-mediated degradation. While proteasome inhibitors stabilize p27(Kip1), agents inhibiting SCF(Skp2) may represent more directly targeted drugs with the promise of enhanced efficacy and reduced toxicity. Using high-throughput screening, we identified Compound A (CpdA), which interfered with SCF(Skp2) ligase function in vitro, and induced specific accumulation of p21 and other SCF(Skp2) substrates in cells without activating a heat-shock protein response.

Pomalidomide and lenalidomide regulate erythropoiesis and fetal hemoglobin production in human CD34+ cells.

Sickle-cell disease (SCD) and beta thalassemia constitute worldwide public health problems. New therapies, including hydroxyurea, have attempted to augment the synthesis of fetal hemoglobin (HbF) and improve current treatment. Lenalidomide and pomalidomide are members of a class of immunomodulators used as anticancer agents.

The tumor suppressor PP2A Abeta regulates the RalA GTPase.

The serine-threonine protein phosphatase 2A (PP2A) is a heterotrimeric enzyme family that regulates numerous signaling pathways. Biallelic mutations of the structural PP2A Abeta subunit occur in several types of human tumors; however, the functional consequences of these cancer-associated PP2A Abeta mutations in cell transformation remain undefined. Here we show that suppression of PP2A Abeta expression permits immortalized human cells to achieve a tumorigenic state.

Immunomodulatory drug CC-4047 is a cell-type and stimulus-selective transcriptional inhibitor of cyclooxygenase 2.

COX2 (prostaglandin G/H synthase, PTGS2) is a well-validated target in the fields of both oncology and inflammation. Despite their significant toxicity profile, non-steroidal anti-inflammatory drugs (NSAIDs) have become standard of care in the treatment of many COX2-mediated inflammatory conditions. In this report, we show that one IMiDs((R)) immunomodulatory drug, CC-4047, can reduce the levels of COX2 and the production of prostaglandins (PG) in human LPS-stimulated monocytes.

Lenalidomide and CC-4047 inhibit the proliferation of malignant B cells while expanding normal CD34+ progenitor cells.

Clinical studies involving patients with myelodysplastic syndromes or multiple myeloma have shown the efficacy of lenalidomide by reducing and often eliminating malignant cells while restoring the bone marrow function. To better understand these clinical observations, we investigated and compared the effects of lenalidomide and a structurally related analogue, CC-4047, on the proliferation of two different human hematopoietic cell models: the Namalwa cancer cell line and normal CD34+ progenitor cells. Both compounds had antiproliferative effects on Namalwa cells and pro-proliferative effects on CD34+ cells, whereas p21WAF-1 expression was up-regulated in both cell types.

B7-h4 is a novel membrane-bound protein and a candidate serum and tissue biomarker for ovarian cancer.

Using cDNA database mining strategies and real-time quantitative reverse transcription-PCR, we identified B7-H4 as a novel gene that is overexpressed in ovarian and breast cancer tissues when compared with normal tissues. The gene encodes a protein of 282 amino acids with a signal sequence, an immunoglobulin domain, and a COOH-terminal hydrophobic transmembrane domain. Immunohistochemistry experiments show plasma membrane staining in serous ovarian and breast cancer, confirming the tissue specificity and cell surface localization.

The synthetic compound CC-5079 is a potent inhibitor of tubulin polymerization and tumor necrosis factor-alpha production with antitumor activity.

We have found that the synthetic compound CC-5079 potently inhibits cancer cell growth in vitro and in vivo by a novel combination of molecular mechanisms. CC-5079 inhibits proliferation of cancer cell lines from various organs and tissues at nanomolar concentrations. Its IC(50) value ranges from 4.

B7-H4 overexpression in ovarian tumors.

Objectives: Despite great advances in therapeutic management, the mortality rate for ovarian cancer has remained relatively stable over the past 50 years. This study was designed to evaluate the expression of B7-H4 protein, recently identified as a potential molecular marker of breast and ovarian cancer by quantitative PCR analysis, in benign tumors, tumors of low malignant potential and malignant tumors of the ovary.

Methods: Archival formalin-fixed tissue blocks from serous, mucinous, endometrioid and clear cell ovarian tumors were evaluated by immunohistochemistry for the distribution of B7-H4 expression, and staining intensity was measured by automated image analysis.

Testisin, a glycosyl-phosphatidylinositol-linked serine protease, promotes malignant transformation in vitro and in vivo.

Human testisin, a serine protease, is highly expressed in ovarian cancer and premeiotic spermatocytes with relatively little expression in other normal tissues. We first showed that testisin was localized on the surface of cultured tumor cells as a glycosyl-phosphatidylinositol-linked protein. We next explored the biological function of testisin in malignant transformation through manipulation of testisin expression in cell culture model systems.

Alpha-fluoro-substituted thalidomide analogues.

Thalidomide, (1), has made a remarkable comeback from its days of a sedative with teratogenic properties due to its ability to selectively inhibit TNF-alpha, a key pro-inflammatory cytokine and its clinical benefit in the treatment of cancer. Thalidomide contains one chiral center and is known to be chirally unstable under in vitro and in vivo conditions. It has been hypothesized that different biological properties are associated with each isomer.

Enhancement of cytokine production and AP-1 transcriptional activity in T cells by thalidomide-related immunomodulatory drugs.

CC-4047 (Actimid) and CC-5013 (Revimid) belong to a class of thalidomide analogs collectively known as the immunomodulatory drugs (IMiDs), which are currently being assessed in the treatment of patients with multiple myeloma and other cancers. IMiDs potently enhance T cell and natural killer cell responses and inhibit tumor necrosis factor-alpha, interleukin (IL)-1 beta, and IL-12 production from LPS-stimulated peripheral blood mononuclear cells. However, the molecular mechanism of action for these compounds is unknown.

Myxobolus desaequalis n. sp. (Myxozoa, Myxosporea), parasite of the Amazonian freshwater fish, Apteronotus albifrons (Teleostei, Apteronotidae).

Myxobolus desaequalis n. sp. is described from the gill lamellae of the freshwater fish Apteronotus albifrons, collected in the Amazon River, near the city of Salvaterra, Brazil.

Viral and bacterial infections induce expression of multiple NK cell receptors in responding CD8(+) T cells.

NK cells express several families of receptors that play central roles in target cell recognition. These NK cell receptors are also expressed by certain memory phenotype CD8(+) T cells, and in some cases are up-regulated in T cells responding to viral infection. To determine how the profile of NK receptor expression changes in murine CD8(+) T cells as they respond to intracellular pathogens, we used class I tetramer reagents to directly examine Ag-specific T cells during lymphocytic choriomeningitis virus and Listeria monocytogenes infections.

Fine structure of spermiogenesis with special reference to the spermatid morulae of the freshwater mussel Prisodon alatus (Bivalvia, Unionoidea).

Within the testicular cysts of the mussel Prisodon alatus are numerous somatic host cells described as Sertoli cells (SC), each containing a variable number of young spermatid morulae. Among them, several free spermatid morulae, spermatids, and spermatozoa were observed. Each free spermatid morula is surrounded by an external membrane.

The fine structure of the spermatozoa of Siphonaria algesirae (Gastropoda, Pulmonata).

The sperm of Siphonaria algesirae (Gastropoda, Pulmonata), a species with internal fertilization, was studied by light and electron microscopy. The spermatozoon is a very long, uniflagellate cell composed of a conical head with an apical acrosome, a midpiece with a helically coiled external sheath containing a complex mitochondrial derivative with a wavelength of ∼ 5.5 μm, and an endpiece.