CDK4 coexpression with Ras generates malignant human epidermal tumorigenesis.

Ras acts with other proteins to induce neoplasia. By itself, however, strong Ras signaling can suppress proliferation of normal cells. In primary epidermal cells, we found that oncogenic Ras transiently decreases cyclin-dependent kinase (CDK) 4 expression in association with cell cycle arrest in G1 phase. CDK4 co-expression circumvents Ras growth suppression and induces invasive human neoplasia resembling squamous cell carcinoma. Tumorigenesis is dependent on CDK4 kinase function, with cyclin D1 required but not sufficient for this process. In facilitating escape from G1 growth restraints, Ras and CDK4 alter the composition of cyclin D and cyclin E complexes and promote resistance to growth inhibition by INK4 cyclin-dependent kinase inhibitors. These data identify a new role for oncogenic Ras in CDK4 regulation and highlight the functional importance of CDK4 suppression in preventing uncontrolled growth.

SC-002 in patients with relapsed or refractory small cell lung cancer and large cell neuroendocrine carcinoma: Phase 1 study.

OBJECTIVES: This phase 1 study investigated safety/tolerability, pharmacokinetics, and preliminary efficacy of SC-002, a delta-like ligand 3-directed antibody-drug conjugate, in advanced small cell lung cancer and large cell neuroendocrine carcinoma. MATERIALS AND METHODS: Eligible patients received SC-002 at 1 of 7 dose levels during the dose-escalation portion of the study. RESULTS: Thirty-five enrolled patients received ≥1 dose of SC-002. Twenty-three (66%) patients experienced serious adverse events (AEs), 37% considered related to SC-002. Grade 3/4 AEs occurred in 21 (60%) and 2 (6%) patients; the most common were effusion and hypoalbuminemia. One grade 5 AE occurred in 1 patient. Five (14%) patients achieved a partial response and no patients achieved a complete response. CONCLUSION: SC-002 treatment was associated with systemic toxicity and limited efficacy.

Topical application of a novel immunomodulatory peptide, RDP58, reduces skin inflammation in the phorbol ester-induced dermatitis model.

RDP58 is the first lead compound in a series of immunomodulating decapeptides discovered through activity-based screening and computer-aided, rational design. RDP58 disrupts cellular responses signaled through the Toll-like and tumor necrosis factor (TNF) receptor families and occludes important signal transduction pathways involved in inflammation, inhibiting the production of tumor necrosis factor alpha (TNFalpha), interferon-gamma, interleukin (IL)-2, IL-6, and IL-12. These pro-inflammatory cytokines are thought to be involved in the pathogenesis of several inflammatory and autoimmune diseases, including atopic dermatitis and psoriasis. The goal of this study was to determine the ability of RDP58 to inhibit skin inflammation following exposure to the well-characterized protein kinase C activator and tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Topical application of RDP58 to the epidermis following TPA treatment resulted in the amelioration of the phorbol ester-induced irritant contact dermatitis. Substantial reductions were observed in skin thickness and tissue weight, neutrophil-mediated myeloperoxidase activity, inflammatory cytokine production, and various histopathological indicators. We also found RDP58 to be effective in reducing the compounding inflammatory damage brought on by chronic TPA exposure, and that it is capable of targeting inflammatory mediators specifically in the keratinocyte. These results demonstrate that topically applied RDP58 is an effective anti-inflammatory treatment in the phorbol ester-induced dermatitis model, and suggest that it may have therapeutic potential in a variety of immune-related cutaneous diseases.

RDP58 is a novel and potentially effective oral therapy for ulcerative colitis.

BACKGROUND: RDP58 is a novel anti-inflammatory d-amino acid decapeptide that inhibits synthesis of proinflammatory cytokines by disrupting cell signaling at the pre-MAPK MyD88-IRAK-TRAF6 protein complex. We therefore evaluated its efficacy and safety in parallel multicenter, double-blind, randomized concept studies in ulcerative colitis (UC). METHODS: In the first trial, 34 patients with mild to moderate active UC were randomized (1:2) to placebo (n = 13) or RDP58 100 mg (n = 21). In the second trial, 93 similar patients were randomized (1:1:1) to placebo (n = 30) RDP58 200 mg (n = 31), or RDP 300 mg (n = 32). In both studies, treatment success was defined as a simple clinical colitis activity index score of no more than 3 at 28 days. Sigmoidoscopy and rectal biopsy (at baseline and 28 days) and safety measures (baseline and 28 and 56 days) were other endpoints. RESULTS: Treatment success on RDP 100 mg was 29% versus 46% on placebo (P = 0.46). There were no significant differences in sigmoidoscopy or histology score. In the second study, treatment success on the higher doses of RDP58 (200 and 300 mg) was 71% and 72%, respectively, versus 43% on placebo (P = 0.016). Improvements in sigmoidoscopy scores (41% on 200 mg and 46% on 300 mg versus 32% on placebo) did not reach significance, but histology scores improved significantly (P = 0.002) versus placebo. Overall, adverse events were no different between placebo (3.3 +/- 2.4) and RDP58 (2.7 +/- 1.4, 300-mg group). CONCLUSIONS: RDP58 at a dose of 200 or 300 mg, but not 100 mg, was effective in mild-to-moderate UC. RDP58 was safe and well tolerated, and its novel action makes it an attractive potential therapy.

Biomarker analyses from a placebo-controlled phase II study evaluating erlotinib±onartuzumab in advanced non-small cell lung cancer: MET expression levels are predictive of patient benefit.

PURPOSE: In a recent phase II study of onartuzumab (MetMAb), patients whose non-small cell lung cancer (NSCLC) tissue scored as positive for MET protein by immunohistochemistry (IHC) experienced a significant benefit with onartuzumab plus erlotinib (O+E) versus erlotinib. We describe development and validation of a standardized MET IHC assay and, retrospectively, evaluate multiple biomarkers as predictors of patient benefit. EXPERIMENTAL DESIGN: Biomarkers related to MET and/or EGF receptor (EGFR) signaling were measured by IHC, FISH, quantitative reverse transcription PCR, mutation detection techniques, and ELISA. RESULTS: A positive correlation between IHC, Western blotting, and MET mRNA expression was observed in NSCLC cell lines/tissues. An IHC scoring system of MET expression taking proportional and intensity-based thresholds into consideration was applied in an analysis of the phase II study and resulted in the best differentiation of outcomes. Further analyses revealed a nonsignificant overall survival (OS) improvement with O+E in patients with high MET copy number (mean≥5 copies/cell by FISH); however, benefit was maintained in "MET IHC-positive"/MET FISH-negative patients (HR, 0.37; P=0.01). MET, EGFR, amphiregulin, epiregulin, or HGF mRNA expression did not predict a significant benefit with onartuzumab; a nonsignificant OS improvement was observed in patients with high tumor MET mRNA levels (HR, 0.59; P=0.23). Patients with low baseline plasma hepatocyte growth factor (HGF) exhibited an HR for OS of 0.519 (P=0.09) in favor of onartuzumab treatment. CONCLUSIONS: MET IHC remains the most robust predictor of OS and progression-free survival benefit from O+E relative to all examined exploratory markers.

Periodontal regeneration using an anabolic peptide with two carriers in baboons.

BACKGROUND: Various growth proteins have been used to encourage periodontal tissue regeneration. The purpose of this pilot study is to evaluate the periodontal regeneration achieved with the use of a synthetic anabolic peptide (AP) combined with either beta-tricalcium phosphate (beta-TCP) or an absorbable collagen sponge (ACS) as the carrier. METHODS: Periodontal defects were created bilaterally adjacent to four mandibular teeth in five baboons. Plaque was allowed to accumulate around wire ligatures placed into the defects. After 2 months, the wire ligatures were removed, and a notch was placed at the base of the defect. The four teeth were randomly treated with one of the following treatments: 1) saline + ACS serving as the control, 2) AP + ACS, 3) saline + beta-TCP serving as another control, or 4) AP + beta-TCP. The baboons were sacrificed 5 months post-treatment, and histomorphometric analyses were performed under masked conditions. RESULTS: At 5 months post-surgery, the mean length of new cementum for sites treated with AP + ACS, AP + beta-TCP, saline + ACS, saline + beta-TCP amounted to 3.32 +/- 1.7 mm, 3.86 +/- 1.0 mm, 2.87 +/- 1.3 mm, and 3.15 +/- 1.9 mm, respectively. The mean width of new cementum for the corresponding values was 52.5 +/- 14.7 microm, 54.5 +/- 24.2 microm, 37.4 +/- 12.7 microm, and 48.9 +/- 12.4 microm, respectively. The mean width of new periodontal ligament for corresponding values was 246 +/- 140 microm, 166 +/- 26 microm, 251 +/- 92 microm, and 240 +/- 91 microm. No statistically significant difference was observed for any of the parameters among groups in this pilot study. CONCLUSIONS: Preclinical studies showed that AP has positive anabolic effects on bone cells. In this study, no adverse tissue reactions were observed in the AP-treated sites, including root resorption, ankylosis, or a foreign body reaction. The cementum length and width were greater in the sites treated with AP versus sites treated with a control; however, these differences were not significant in the small number of animals used. Further research is needed to define the potential of AP as a periodontal therapeutic agent.

NF-kappaB blockade and oncogenic Ras trigger invasive human epidermal neoplasia.

The nuclear factor NF-kappaB and oncogenic Ras can alter proliferation in epidermis, the most common site of human cancer. These proteins are implicated in epidermal squamous cell carcinoma in mice, however, the potential effects of altering their function are uncertain. Whereas inhibition of NF-kappaB enhances apoptosis in certain tumours, blockade of NF-kappaB predisposes murine skin to squamous cell carcinoma. Because therapeutics inhibiting Ras and NF-kappaB pathways are being developed to treat human cancer, it is essential to assess the effects of altering these regulators. The medical relevance of murine studies is limited, however, by differences between mouse and human skin, and by the greater ease of transforming murine cells. Here we show that in normal human epidermal cells both NF-kappaB and oncogenic Ras trigger cell-cycle arrest. Growth arrest triggered by oncogenic Ras can be bypassed by IkappaBalpha-mediated blockade of NF-kappaB, generating malignant human epidermal tissue resembling squamous cell carcinoma. Human cell tumorigenesis is dependent on laminin 5 and alpha6beta4 integrin. Thus, IkappaBalpha circumvents restraints on growth promotion induced by oncogenic Ras and can act with Ras to induce invasive human tissue neoplasia.