Extant evidence implicates growth factor signaling in the pathogenesis of many tumor types, including cutaneous melanoma. Recently, reciprocal activating mutations of NRAS and BRAF were found in benign melanocytic nevi and cutaneous melanomas. We had previously reported a similar epistatic relationship between activating NRAS mutations and inactivating PTEN/MMAC1 alterations. We thus hypothesized that BRAF and PTEN/MMAC1 mutations may cooperate to promote melanoma tumorigenesis. Overall, 40 of 47 (85%) melanoma cell lines and 11 of 16 (69%) uncultured melanoma metastases had mutations in NRAS, BRAF, or PTEN/MMAC1. NRAS was exclusively mutated in nine of 47 (19%) cell lines and two of 16 (13%) metastases, whereas BRAF was solely mutated in 28 of 47 (60%) cell lines and nine of 16 (56%) metastases. In the 12 of 15 melanoma cell lines (80%) and two of two melanoma metastases with PTEN alterations, BRAF was also mutated. These findings suggest the existence of possible cooperation between BRAF activation and PTEN loss in melanoma development.

GenoMEL, comprising major familial melanoma research groups from North America, Europe, Asia, and Australia has created the largest familial melanoma sample yet available to characterize mutations in the high-risk melanoma susceptibility genes CDKN2A/alternate reading frames (ARF), which encodes p16 and p14ARF, and CDK4 and to evaluate their relationship with pancreatic cancer (PC), neural system tumors (NST), and uveal melanoma (UM). This study included 466 families (2,137 patients) with at least three melanoma patients from 17 GenoMEL centers. Overall, 41% (n = 190) of families had mutations; most involved p16 (n = 178). Mutations in CDK4 (n = 5) and ARF (n = 7) occurred at similar frequencies (2-3%). There were striking differences in mutations across geographic locales. The proportion of families with the most frequent founder mutation(s) of each locale differed significantly across the seven regions (P = 0.0009). Single founder CDKN2A mutations were predominant in Sweden (p.R112_L113insR, 92% of family's mutations) and the Netherlands (c.225_243del19, 90% of family's mutations). France, Spain, and Italy had the same most frequent mutation (p.G101W). Similarly, Australia and United Kingdom had the same most common mutations (p.M53I, c.IVS2-105A>G, p.R24P, and p.L32P). As reported previously, there was a strong association between PC and CDKN2A mutations (P < 0.0001). This relationship differed by mutation. In contrast, there was little evidence for an association between CDKN2A mutations and NST (P = 0.52) or UM (P = 0.25). There was a marginally significant association between NST and ARF (P = 0.05). However, this particular evaluation had low power and requires confirmation. This GenoMEL study provides the most extensive characterization of mutations in high-risk melanoma susceptibility genes in families with three or more melanoma patients yet available. (Cancer Res 2006; 66(20): 9818-28)

Exosomes are endosome-derived membrane vesicles carrying proteins and nucleic acids that are involved in cellular functions such as intercellular communication, protein and RNA secretion, and antigen presentation. Therefore, exosomes serve as potential biomarkers for many diseases including cancer. Because exosomes are difficult to enrich or purify from biofluids, quantification of exosomes is tedious and inaccurate. Here, we present a real-time, label-free, and quantitative method to detect and characterize tumor-derived exosomes without enrichment or purification. Utilizing surface plasmon resonance imaging (SPRi) in combination with antibody microarrays specific to the extracellular domains of exosome membrane proteins, exosomes in tumor cell culture medium can be quantitatively detected. We found a positive correlation between the metastatic potential of tumor cell lines and exosome secretion. This method provides an easy, efficient, and novel way to detect exosome secretion and thus an avenue toward the diagnosis and prognosis prediction of cancer.

Developing a sophisticated nanomedicine platform to deliver therapeutics effectively and safely into tumor/cancer cells remains challenging in the field of nanomedicine. In particular, reliable peptide drug delivery systems capable of overcoming biological barriers are still lacking. Here, we developed a simple, rapid, and robust strategy to manufacture nanoclusters of ∼90 nm in diameter that are self-assembled from lanthanide-doped nanoparticles (5 nm), two anticancer peptides with different targets (BIM and PMI), and one cyclic peptide iNGR targeted to cancer cells. The peptide-lanthanide nanoclusters (LDC-PMI-BIM-iNGR) enhanced the resistance of peptide drugs to proteolysis, disassembled in response to reductive conditions that are present in the tumor microenvironment and inhibited cancer cell growth in vitro and in vivo. Notably, LDC-PMI-BIM-iNGR exhibited extremely low systemic toxicity and side effects in vivo. Thus, the peptide-lanthanide nanocluster may serve as an ideal multifunctional platform for safe, targeted, and efficient peptide drug delivery in cancer therapy.

Five new phenolic compounds, gramniphenols C-G (1-5), and eight known compounds (6-13) were isolated from the whole plant of Arundina gramnifolia. Compounds 1, 4, and 5 showed anti-tobacco mosaic virus activity, with IC(50) values of 20.8, 40.8, and 57.7 μM, respectively. Compounds 1-10 were also tested for their anti-HIV-1 activity; compounds 2, 3, and 6 displayed anti-HIV-1 activity with therapeutic index values above 100:1.

In a recent genome-wide association study, hexokinase domain-containing protein 1, or HKDC1, was found to be associated with gestational glucose levels during 2-hour glucose tolerance tests at 28 weeks of pregnancy. Because our understanding of the mediators of gestational glucose homeostasis is incomplete, we have generated the first transgenic mouse model to begin to understand the role of HKDC1 in whole-body glucose homeostasis. Interestingly, deletion of both HKDC1 alleles results in in utero embryonic lethality. Thus, in this study, we report the in vivo role of HKDC1 in whole-body glucose homeostasis using a heterozygous-deleted HKDC1 mouse model (HKDC1(+/-)) as compared with matched wild-type mice. First, we observed no weight, fasting or random glucose, or fasting insulin abnormalities with aging in male and female HKDC1(+/-) mice. However, during glucose tolerance tests, glucose levels were impaired in both female and male HKDC1(+/-) mice at 15, 30, and 120 minutes at a later age (28 wk of age). These glucose tolerance differences also existed in the female HKDC1(+/-) mice at earlier ages but only during pregnancy. And finally, the impaired glucose tolerance in HKDC1(+/-) mice was likely due to diminished whole-body glucose use, as indicated by the decreased hepatic energy storage and reduced peripheral tissue uptake of glucose in HKDC1(+/-) mice. Collectively, these data highlight that HKDC1 is needed to maintain whole-body glucose homeostasis during pregnancy but also with aging, possibly through its role in glucose use.

Epidermal melanocytes execute specific physiological programs in response to UV radiation (UVR) at the cutaneous interface. Many melanocytic responses, including increased dendrite formation, enhanced melanogenesis/melanization, and cell cycle arrest impact the ability of melanocytes to survive and to attenuate the UVR insult. Although some of the molecules that underlie these UVR programs are known, a coherent view of UVR-induced transcriptional changes is lacking. Using primary melanocyte cultures, we assessed for UVR-mediated alterations in over 47,000 transcripts using Affymetrix Human Genome U133 Plus 2.0 microarrays. From the 100 most statistically robust changes in transcript level, there were 84 genes that were suppressed>2.0-fold by UVR; among these transcripts, the identities of 48 of these genes were known. Similarly, there were 99 genes that were induced >2.0-fold by UVR; the identity of 57 of these genes were known. We then subjected these top 100 changes to the Ingenuity Pathway analysis program and identified a group of p53 targets including the cell cycle regulator CDKN1A (p21CIP), the WNT pathway regulator DKK1 (dickkopf homolog 1), the receptor tyrosine kinase EPHA2, growth factor GDF15, ferrodoxin reductase (FDXR), p53-inducible protein TP53I3, transcription factor ATF3, DNA repair enzyme DDB2, and the beta-adrenergic receptor ADBR2. These genes were also found to be consistently elevated by UVR in six independent melanocyte lines, although there were interindividual variations in magnitude. WWOX, whose protein product interacts and regulates p53 and p73, was found to be consistently suppressed by UVR. There was also a subgroup of neurite/axonal developmental genes that were altered in response to UVR, suggesting that melanocytic and neuronal arborization may share similar mechanisms. When compared to melanomas, the basal levels of many of these p53-responsive genes were greatly dysregulated. Three genes--CDKN1A, DDB2 and ADRB2--exhibited a trend towards loss of expression in melanomas thereby raising the possibility of a linked role in tumorigenesis. These expression data provide a global view of UVR-induced changes in melanocytes and, more importantly, generate novel hypotheses regarding melanocyte physiology.

The elevated level of CCNB1 indicates more aggressive cancer and poor prognosis. However, the factors that cause CCNB1 upregulation remain enigmatic. Herein, we identify USP22 as a CCNB1 interactor and discover that both USP22 and CCNB1 are dramatically elevated with a strong positive correlation in colon cancer tissues. USP22 stabilizes CCNB1 by antagonizing proteasome-mediated degradation in a cell cycle-specific manner. Phosphorylation of USP22 by CDK1 enhances its activity in deubiquitinating CCNB1. The ubiquitin ligase anaphase-promoting complex (APC/C) targets USP22 for degradation by using the substrate adapter CDC20 during cell exit from M phase, presumably allowing CCNB1 degradation. Finally, we discover that USP22 knockdown leads to slower cell growth and reduced tumor size. Our study demonstrates that USP22 is a CCNB1 deubiquitinase, suggesting that targeting USP22 might be an effective approach to treat cancers with elevated CCNB1 expression.