Citations

AbstractCytokines are deregulated in cancers and can contribute to tumor growth. In patients with diffuse large-cell lymphoma (DLBCL), we observed higher levels of JAK/STAT pathway-related serum cytokines (ie, IL-6, IL-10, epidermal growth factor, and IL-2) compared with controls. Of these, only IL-10 activated the JAK2 pathway in lymphoma cells in vitro. Patients with high serum IL-10 had shorter event-free survival (EFS) than patients with low levels (P > .01) and high IL-10 was correlated with high lactase dehydrogenase (P = .0085) and higher International Prognostic Index scores (P = .01). To explore the mechanism by which IL-10 may contribute to an inferior EFS, we investigated the effect of IL-10 on the JAK2 pathway and found that the IL-10/IL-10 receptor complex up-regulated JAK2 signaling. Neutralizing Ab to IL-10 inhibited constitutive and IL-10–induced JAK2/STAT3 phosphorylation. JAK2 inhibition dephosphorylated JAK2 and STAT3 and caused an inhibitory effect on phospho-JAK2–positive DLBCL cells; there was a minimal effect on phospho-JAK2–negative cells. Apoptosis induced by JAK2 inhibition was dependent on inhibition of autocrine IL-10 and c-myc expression and independent of Bcl-2 family expression. These results provide the rationale for testing JAK2 inhibitors in DLBCL patients, and indicate that serum IL-10 may be a biomarker to identify patients more likely to respond to JAK2-targeted therapy.

Renal function and blood flow decline during aging in association with a decrease in the number of intrarenal vessels, but if loss of estrogen contributes to this microvascular, rarefaction remains unclear. We tested the hypothesis that the decreased renal microvascular density with age is aggravated by loss of estrogen. Six-month-old female C57/BL6 mice underwent ovariectomy (Ovx) or sham operation and then were allowed to age to 18–22 mo. Another comparable group was replenished with estrogen after Ovx (Ovx+E), while a 6-mo-old group served as young controls. Kidneys were then dissected for evaluation of microvascular density (by micro-computed tomography) and angiogenic and fibrogenic factors. Cortical density of small microvessels (20–200 μm) was decreased in all aged groups compared with young controls (30.3 ± 5.8 vessels/mm2, P < 0.05), but tended to be lower in sham compared with Ovx and Ovx+E (9.9 ± 1.7 vs. 17.2 ± 4.2 and 18 ± 3.0 vessels/mm2, P = 0.08 and P = 0.02, respectively). Cortical density of larger microvessels (200–500 μm) decreased only in aged sham ( P = 0.04 vs. young control), and proangiogenic signaling was attenuated. On the other hand, renal fibrogenic mechanisms were aggravated in aged Ovx compared with aged sham, but blunted in Ovx+E, in association with downregulated transforming growth factor-β signaling and decreased oxidative stress in the kidney. Therefore, aging induced in female mice renal cortical microvascular loss, which was likely not mediated by loss of endogenous estrogen. However, estrogen may play a role in protecting the kidney by decreasing oxidative stress and attenuating mechanisms linked to renal interstitial fibrosis.

Abstract The mammalian target of rapamycin (mTOR) plays crucial roles in proliferative and antiapoptotic signaling in lymphoid malignancies. Rapamycin analogs, which are allosteric mTOR complex 1 (mTORC1) inhibitors, are active in mantle cell lymphoma and other lymphoid neoplasms, but responses are usually partial and short-lived. In the present study we compared the effects of rapamycin with the dual mTORC1/mTORC2 inhibitor OSI-027 in cell lines and clinical samples representing divers lymphoid malignancies. In contrast to rapamycin, OSI-027 markedly diminished proliferation and induced apoptosis in a variety of lymphoid cell lines and clinical samples, including specimens of B-cell acute lymphocytic leukemia (ALL), mantle cell lymphoma, marginal zone lymphoma and Sezary syndrome. Additional analysis demonstrated that OSI-027–induced apoptosis depended on transcriptional activation of the PUMA and BIM genes. Overexpression of Bcl-2, which neutralizes Puma and Bim, or loss of procaspase 9 diminished OSI-027–induced apoptosis in vitro. Moreover, OSI-027 inhibited phosphorylation of mTORC1 and mTORC2 substrates, up-regulated Puma, and induced regressions in Jeko xenografts. Collectively, these results not only identify a pathway that is critical for the cytotoxicity of dual mTORC1/mTORC2 inhibitors, but also suggest that simultaneously targeting mTORC1 and mTORC2 might be an effective anti-lymphoma strategy in vivo.

Abstract Triple-negative breast cancers are an aggressive subtype of breast cancer with poor survival, but there remains little known about the etiologic factors that promote its initiation and development. Commonly inherited breast cancer risk factors identified through genome-wide association studies display heterogeneity of effect among breast cancer subtypes as defined by the status of estrogen and progesterone receptors. In the Triple Negative Breast Cancer Consortium (TNBCC), 22 common breast cancer susceptibility variants were investigated in 2,980 Caucasian women with triple-negative breast cancer and 4,978 healthy controls. We identified six single-nucleotide polymorphisms, including rs2046210 (ESR1), rs12662670 (ESR1), rs3803662 (TOX3), rs999737 (RAD51L1), rs8170 (19p13.1), and rs8100241 (19p13.1), significantly associated with the risk of triple-negative breast cancer. Together, our results provide convincing evidence of genetic susceptibility for triple-negative breast cancer. Cancer Res; 71(19); 6240–9. ©2011 AACR.

BackgroundThe cerebrospinal fluid (CSF) biomarkers amyloid β (Aβ)‐42, total‐tau (T‐tau), and phosphorylated‐tau (P‐tau) demonstrate good diagnostic accuracy for Alzheimer's disease (AD). However, there are large variations in biomarker measurements between studies, and between and within laboratories. The Alzheimer's Association has initiated a global quality control program to estimate and monitor variability of measurements, quantify batch‐to‐batch assay variations, and identify sources of variability. In this article, we present the results from the first two rounds of the program.MethodsThe program is open for laboratories using commercially available kits for Aβ, T‐tau, or P‐tau. CSF samples (aliquots of pooled CSF) are sent for analysis several times a year from the Clinical Neurochemistry Laboratory at the Mölndal campus of the University of Gothenburg, Sweden. Each round consists of three quality control samples.ResultsForty laboratories participated. Twenty‐six used INNOTEST enzyme‐linked immunosorbent assay kits, 14 used Luminex xMAP with the INNO‐BIA AlzBio3 kit (both measure Aβ‐(1‐42), P‐tau(181P), and T‐tau), and 5 used Meso Scale Discovery with the Aβ triplex (AβN‐42, AβN‐40, and AβN‐38) or T‐tau kits. The total coefficients of variation between the laboratories were 13% to 36%. Five laboratories analyzed the samples six times on different occasions. Within‐laboratory precisions differed considerably between biomarkers within individual laboratories.ConclusionsMeasurements of CSF AD biomarkers show large between‐laboratory variability, likely caused by factors related to analytical procedures and the analytical kits. Standardization of laboratory procedures and efforts by kit vendors to increase kit performance might lower variability, and will likely increase the usefulness of CSF AD biomarkers.

The genome sequence of a lycophyte hints at ancient evolutionary transitions.

Tumor cell migration is supported in part by the cyclic formation and disassembly of focal adhesions (FAs); however, the mechanisms that regulate this process are not fully defined. The large guanosine 5′-triphosphatase dynamin (Dyn) plays an important role in FA dynamics and is activated by tyrosine phosphorylation. Using a novel antibody specific to phospho-dynamin (pDyn–Tyr-231), we found that Dyn2 is phosphorylated at FAs by Src kinase and is recruited to FAs by a direct interaction with the 4.1/ezrin/radizin/moesin domain of focal adhesion kinase (FAK), which functions as an adaptor between Src and Dyn2 to facilitate Dyn2 phosphorylation. This Src–FAK–Dyn2 trimeric complex is essential for FA turnover, as mutants disrupting the formation of this complex inhibit FA disassembly. Importantly, phosphoactivated Dyn2 promotes FA turnover by mediating the endocytosis of integrins in a clathrin-dependent manner. This study defines a novel mechanism of how Dyn2 functions as a downstream effector of FAK–Src signaling in turning over FAs.

Abstract We have previously reported that the protease activity of uPA delays tumor progression in a syngeneic model of breast cancer, and that the inhibitory effects are due to the protease activity of uPA (Merchan et. al, JNCI, 2006: 7; 98(11)). We also reported that changes in the uPA/PAI-1 balance favoring the proteolytic activity of uPA are associated with delayed tumor growth and reduction in lung metastases in vivo (Jing, et al, AACR 2009 meeting, #1124). The aim of this study was to extend the above findings in other in vivo syngeneic cancer models and to characterize the changes in gene expression mediated by uPA overexpression. We generated stably uPA overexpressing murine renal cancer (RENCA) and murine colon cancer (MC-38) cell lines using lentiviral vectors carrying m-uPA and selecting high uPA expressing clones for in vivo studies. uPA protein expression and in vitro growth was similar between the uPA overexpressing and control cancer cells. Similar with our findings in the 4T1 model, mice harboring RENCA tumors overexpressing uPA had reduced tumor growth than controls. Conversely, mice carrying uPA-overexpressing MC-38 tumors had significantly enhanced tumor growth compared to controls. To understand the causes for the opposite in vivo effects of uPA overexpressing RENCA and MC-38 tumors, we first compared uPA's proteolytic activity vs. protein concentration between both cell lines. To our surprise, the uPA proteolytic activity of (uPA overexpressing) MC-38 conditioned medium (CM) was significantly lower (&gt; 15-fold) than that of stable RENCA cell lines even though uPA protein levels were comparable. To assess if the differences in uPA proteolytic activity between MC38 and RENCA transfectants was due to differential endogenous PAI-1 expression, we measured PAI-1 levels in MC38 and RENCA transfectants CM (ELISA). We found that PAI-1 expression in MC 38 was significantly higher (30-fold) than RENCA cells. The above data strongly suggest that in MC-38 tumors, uPA overexpression promoted tumor growth in part due to high endogenous PAI-1 levels. On the other hand, in the RENCA model, uPA overexpression (and low PAI-1 expression) was associated with significantly enhanced proteolytic activity and delayed tumor growth. Gene expression arrays of early murine mammary tumors overexpressing active uPA, showed significant tumor down regulation of several members of the MMP family, which may explain the in vivo antitumor effects. The above data suggest that the pro-or anti tumorigenic/metastatic effects of uPA overexpression depend on its proteolytic activity, and indicate that the status of endogenous tumor PAI-1 may regulate uPA's effects on tumor progression and metastases. The above data may help reconcile contradictory experimental and clinical findings on the role of proteases and protease inhibitors on tumor progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 516.

SP/KLF (Specificity protein/Krüppel-like factor) transcription factors comprise an emerging group of proteins that may behave as tumour suppressors. Incidentally, many cancers that display alterations in certain KLF proteins are also associated with a high incidence of KRAS (V-Ki-ras2 Kirsten rat sarcoma viral oncogene homologue) mutations. Therefore in the present paper we investigate whether SP/KLF proteins suppress KRAS-mediated cell growth, and more importantly, the potential mechanisms underlying these effects. Using a comprehensive family-wide screening of the 24 SP/KLF members, we discovered that SP5, SP8, KLF2, KLF3, KLF4, KLF11, KLF13, KLF14, KLF15 and KLF16 inhibit cellular growth and suppress transformation mediated by oncogenic KRAS. Each protein in this subset of SP/KLF members individually inhibits BrdU (5-bromo-2-deoxyuridine) incorporation in KRAS oncogenic-mutant cancer cells. SP5, KLF3, KLF11, KLF13, KLF14 and KLF16 also increase apoptosis in these cells. Using KLF11 as a representative model for mechanistic studies, we demonstrate that this protein inhibits the ability of cancer cells to form both colonies in soft agar and tumour growth in vivo. Molecular studies demonstrate that these effects of KLF11 are mediated, at least in part, through silencing cyclin A via binding to its promoter and leading to cell-cycle arrest in S-phase. Interestingly, similar to KLF11, KLF14 and KLF16 mechanistically share the ability to modulate the expression of cyclin A. Collectively, the present study stringently defines a distinct subset of SP/KLF proteins that impairs KRAS-mediated cell growth, and that mechanistically some members of this subset accomplish this, at least in part, through regulation of the cyclin A promoter.