Effect of everolimus on the pharmacokinetics of octreotide long-acting repeatable in patients with advanced neuroendocrine tumors: An analysis of the randomized phase III RADIANT-2 trial.

In the RADIANT-2 trial, addition of everolimus to octreotide long-acting repeatable (LAR) exhibited a clinically meaningful 5.1-month improvement in progression-free survival (PFS) in patients with advanced functional neuroendocrine tumors. In this study, we characterized the effects of everolimus co-administration on octreotide LAR pharmacokinetics and its relationship with efficacy and safety. At least one evaluable blood everolimus and plasma octreotide predose minimum concentration (Cmin ) was available for 182 patients and 294 patients, respectively. Concomitant everolimus administration increased octreotide Cmin with a geometric mean ratio (everolimus/placebo) of 1.47 (90% confidence interval [CI] = 1.32-1.64). Risk for progression was consistently reduced when everolimus Cmin was increased twofold, regardless of octreotide exposure (hazard ratio [HR] = 0.74; 95% CI = 0.46-1.18; HR = 0.54; 95% CI = 0.32-0.92 for 6 ng/mL and 4 ng/mL octreotide, respectively). Risk for pulmonary or metabolic events was associated with increased everolimus Cmin . Co-administration of everolimus plus octreotide LAR increased octreotide Cmin , which did not impact efficacy.

Induction of graft versus malignancy effect after unrelated allogeneic PBSCT using donor lymphocyte infusions derived from frozen aliquots of the original graft.

To evaluate safety and efficacy of donor lymphocyte infusions (DLI), derived from frozen aliquots of the original G-CSF-stimulated graft after allogeneic PBSCT from unrelated donors, data of 121 patients with hematological malignancies treated with DLIs were retrospectively analyzed. Indications for PBSCT were AML/myelodysplastic syndrome (n=63/8), ALL (n=17), lymphoma (n=13), multiple myeloma (n=10) and myeloproliferative syndrome (n=10). Reasons for DLI were hematological relapse (n=81), molecular and/or cytogenetic relapse (n=5), mixed chimerism (n=22) and prophylactic DLI in high-risk patients (n=13). DLIs were well tolerated with no acute adverse reactions. DLI-induced acute-type GvHD (aGvHD) was observed in 19 patients and chronic-type GvHD (cGvHD) developed in 14 patients. Three patients died of GvHD complications. DLI induced CR, complete chimerism or PR in 34 patients; 24 patients had stable disease, 50 patients progressed and 13 patients were not evaluable for response. Objective response was more obvious for molecular relapse (5/5) or mixed chimerism (14/22) compared with hematological relapse (13/81). Median survival after first DLI was 10.4 months (95% confidence interval: 4.4-26.0). Cryopreserved G-CSF-stimulated DLI, derived from allogeneic grafts are safe and immunoreactive, and can be applied early in case of mixed chimerism and molecular or cytogenetic relapse.

Inhibition of Id proteins by a peptide aptamer induces cell-cycle arrest and apoptosis in ovarian cancer cells.

BACKGROUND: Inhibitors of DNA-binding proteins (Id1-4), lacking the basic DNA-binding domain, function as dominant inhibitors of cell-cycle regulators. Overexpression of Id proteins promotes cancer cell proliferation and resistance against apoptosis. Level of Id protein expression, especially of Id1, correlates with poor differentiation, enhanced malignant potential and more aggressive clinical behaviour of ovarian tumours. Although overexpression of Ids has been found and shown to correlate with poor clinical outcome, their inhibition at protein level has never been studied. METHODS: A peptide aptamer, Id1/3-PA7, targeting Id1 and Id3, was isolated from a randomised combinatorial expression library using yeast and mammalian two-hybrid systems. Id1/3-PA7 was fused, expressed and purified with a cell-penetrating protein transduction domain. RESULTS: Intracellular-delivered Id1/3-PA7 colocalised to Id1 and Id3. It induced cell-cycle arrest and apoptosis in ovarian cancer cells ES-2 and PA-1. It activated the E-box promoter and increased the expression level of cyclin-dependent kinase inhibitor (CDKN2A) in a dose-dependent manner that is paralleled by the cleavage of poly-ADP ribose polymerase. These effects were counteracted by ectopically overexpressed Id1 and Id3. CONCLUSION: Id1/3-PA7 could represent an exogenous anti-tumour agent that can significantly trigger cell-cycle arrest and apoptosis in ovarian cancer.

BI_2536--targeting the mitotic kinase Polo-like kinase 1 (Plk1).

Human Polo-like kinase 1 (Plk1) is an essential regulator of mitotic progression. Targeted inhibition of this kinase was effective in killing tumor cells in vitro and in vivo. The Plk1 inhibitor BI_2536 was well tolerated and showed antitumor activity in the first clinical trials enrolling patients with advanced solid tumors and refractory or relapsed acute myeloid leukemia.

Interference of the dominant negative helix-loop-helix protein ID1 with the proteasomal subunit S5A causes centrosomal abnormalities.

The inhibitor of DNA-binding (ID) proteins are dominant-negative inhibitors of basic helix-loop-helix transcription factors that have multiple functions during development and cellular differentiation. High-level expression of some ID family members has been observed in human malignancies, and in some cases was correlated with poor clinical prognosis. Ectopic ID1 expression extends the life span of primary human epithelial cells, inhibits cellular differentiation and induces centrosome duplication errors, thus suggesting that ID1 may have oncogenic activities. ID1 can bind to the proteasomal subunit S5A/Rpn10, but the biological consequences of the interaction have not been studied in detail. Here, we show that ID1's ability to induce supernumerary centrosomes correlates with S5A binding. Similar to ID1, a fraction of the S5A protein localizes to centrosomal structures. Furthermore, partial depletion of S5A by RNA interference causes accumulation of cells with supernumerary centrosomes. These results are consistent with the model that ID1 dysregulates centrosome homeostasis at least in part by interfering with S5A activities at the centrosome.

[Origin and role of aneuploidy in cancer]. / Entstehung und Bedeutung von numerischen Chromosomenveränderungen bei bösartigen Tumorerkrankungen.

Genetic aberrations of cancer cells have a profound impact for prognosis in several malignant neoplasias. The understanding of their origin is the basis for the development of new therapeutic options. Aneuploidy is observed in a large variety of premalignancies and tumors. Aneuploid cells harbor less or more than 46 chromosomes. The exact role of aneuploidy in tumorigenesis is still not clear. It has long been debated, whether aneuploidy directly contributes to tumorigenesis or reflects nonspecific changes during tumor progression. Several mechanisms are thought to be responsible for the generation of aneuploid sets of chromosomes: these comprise failure in cell division, such as defective chromosome separation caused by compromised mitotic checkpoint signaling or centrosome aberrations. Moreover, telomere shortening and defective DNA-damage signaling appear to be powerful driving forces of genomic instability. The loss of telomere sequences at the end of each chromosome and DNA double-strand breakage accompanied by compromised damage signaling favor fusion of chromosomes and generation of aneuploidy. Furthermore, aneuploidy arises to a much higher degree from a tetraploid state when compared to diploid cells. The frequent observation of the described defects in pre- and malignant cells supports the hypothesis that aneuploidy contributes to tumorigenesis.

Differential cell cycle response of nontumorigenic and tumorigenic human papillomavirus-positive keratinocytes towards transforming growth factor-beta1.

Human papillomaviruses (HPVs) are causative agents of a number of malignancies in humans, including cervical cancer. Their tumorigenic potential is linked to expression of the viral E6/E7 genes which can interfere with normal cell cycle control by targeting p53, p21WAF1, p27KIP1, and pRb. We show here that nontumorigenic and tumorigenic HPV-positive keratinocytes (HPK) exhibit striking differences in the response of cell cycle regulatory genes towards transforming growth factor beta-beta1. Treatment with this agent led to an efficient induction of p53 and the growth-inhibitory p15INK4 and p21WAF1 genes only in nontumorigenic HPKs and was linked to an efficient reduction in viral E6/E7 oncogene expression. This was associated with increased pRb levels, exhibiting sustained hypophosphorylation, and a permanent growth arrest in the G1 phase of the cell cycle. In contrast, tumorigenic HPKs exhibited only a modest rise in p53 protein levels and a substantially reduced induction of the p15INK4 and p21WAF1 genes, which was linked to a lesser degree of viral oncogene repression. In addition, tumorigenic HPKs rapidly resumed cell growth after a transient G1 arrest, concomitantly with the reappearance of hyperphosphorylated pRb. These results support the notion that the progression of HPV-positive cells to a malignant phenotype is associated with increased resistance to growth inhibition by transforming growth factor-beta1. This is linked in the tumorigenic cells to a lack of persistent G1 arrest, inefficient induction of several cell cycle control genes involved in growth inhibition, and inefficient repression of the growth-promoting viral E6/E7 oncogenes.

Immortalization of primary human keratinocytes by the helix-loop-helix protein, Id-1.

Basic helix-loop-helix (bHLH) DNA-binding proteins have been demonstrated to regulate tissue-specific transcription within multiple cell lineages. The Id family of helix-loop-helix proteins does not possess a basic DNA-binding domain and functions as a negative regulator of bHLH proteins. Overexpression of Id proteins within a variety of cell types has been shown to inhibit their ability to differentiate under appropriate conditions. We demonstrate that ectopic expression of Id-1 leads to activation of telomerase activity and immortalization of primary human keratinocytes. These immortalized cells have a decreased capacity to differentiate as well as activate phosphorylation of the retinoblastoma protein. Additionally, these cells acquire an impaired p53-mediated DNA-damage response as a late event in immortalization. We conclude that bHLH proteins play a pivotal role in regulating normal keratinocyte growth and differentiation, which can be disrupted by the immortalizing functions of Id-1 through activation of telomerase activity and inactivation of the retinoblastoma protein.

Alterations in cyclin-dependent kinase 2 function during differentiation of primary human keratinocytes.

Terminal differentiation of epithelial cells is intimately linked to cell-cycle withdrawal. The tight coupling of these two processes is critical to maintenance of epidermal tissue homeostasis and is frequently disrupted in squamous cell carcinoma. To identify possible molecular targets of epithelial carcinogenesis, we investigated the regulatory pathways that couple cellular differentiation and proliferation in primary cultures of human keratinocytes and found that the cyclin-dependent kinase inhibitors (CKIs) p21cip1/waf1 and p27kip1 were induced early during differentiation of human keratinocytes, whereas p15ink4B was induced later in differentiation. The induction of p21c1/waf1 was mediated by both transcriptional and non-transcriptional mechanisms, and the activities of cyclin A/cyclin-dependent kinase (cdk) 2 and cyclin E/cdk2 complexes were specifically inhibited during keratinocyte differentiation. In contrast, p21cip1/wafl did not associate with cdk4, and the activities of cdk4 complexes remained unchanged. Hence, our results support the model that multiple CKIs participate in linking cellular proliferation and differentiation in human keratinocytes by specific modulation of cdk2 activity.