Purpose: Elevated cyclin D1 in human pancreatic cancer correlates with poor prognosis.Because pancreatic cancer is invariably resistant to chemotherapy, the goal of this study was to examine whether the drug resistance of pancreatic cancer cells is in part attributed to cyclin D1 overexpression. Experimental Design: Stable overexpression and small interfering RNA (siRNA)^mediated knockdown of cyclin D1 were done in the newly established Ela-myc pancreatic tumor cell line. Cisplatin sensitivity of control, overexpressing, and siRNA-transfected cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, clonogenic, and apoptotic assays [DNA fragmentation, sub-G 1 , and poly(ADP-ribose) polymerase cleavage analysis]. The role of nuclear factor-nB and apoptotic proteins in cyclin D1-mediated chemoresistance was examined by EMSA and Western blotting, respectively. Results: Overexpression of cyclin D1in Ela-myc pancreatic tumor cells promoted cell proliferation and anchorage-independent growth. Moreover, cyclin D1^overexpressing cells exhibited significantly reduced chemosensitivity and a higher survival rate upon cisplatin treatment, as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and clonogenic assays, respectively. Although overexpression of cyclin D1 rendered cells more resistant to cisplatininduced apoptosis, siRNA-directed suppression of cyclin D1 expression resulted in enhanced susceptibility to cisplatin-mediated apoptosis. The attenuation of cisplatin-induced cell death in cyclin D1^overexpressing cells was correlated with the up-regulation of nuclear factor-nB activity and maintenance of bcl-2 and bcl-xl protein levels. Conclusions: These results suggest that overexpression of cyclin D1 can contribute to chemoresistance of pancreatic cancer cells because of the dual roles of cyclin D1 in promoting cell proliferation and in inhibiting drug-induced apoptosis.Human pancreatic cancer is an aggressive disease that currently has no viable treatment. This is mainly due to late diagnosis and resistance of the cancer cells to conventional chemotherapeutic agents (1 -3). Previous studies have addressed the clinical relevance of cyclin D1 in pancreatic cancer (4 -7). A significant proportion of pancreatic cancer cases show overexpression of the cyclin D1 gene (5, 8). Furthermore, increased cyclin D1 expression is associated with poor prognosis (5) and decreased postoperative patient survival (8). However, the molecular mechanisms underlying the poor prognostic value of elevated cyclin D1 in pancreatic cancer remain unknown.The proto-oncogenic function of cyclin D1 has been attributed in part to its role in promoting cell cycle progression. Cyclin D1 is a key cell cycle regulator of the G 1 to S phase progression (9, 10). The binding of cyclin D1 to cyclindependent kinase (cdk4 or cdk6) leads to the phosphorylation of retinoblastoma protein (pRb) subsequently triggering the release of E2F transcription factors to allow transcription of genes required f...

PURPOSE This study reports a phase I immunotherapy (IT) trial in 23 women with metastatic breast cancer consisting of eight infusions of anti-CD3 × anti-HER2 bispecific antibody (HER2Bi) armed anti-CD3 activated T cells (ATC) in combination with low dose interleukin 2 (IL-2) and granulocyte-macrophage-colony stimulating factor to determine safety, maximum tolerated dose (MTD), technical feasibility, T cell trafficking, immune responses, time to progression, and overall survival (OS). EXPERIMENTAL DESIGN ATC were expanded from leukapheresis product using IL-2 and anti-CD3 monoclonal antibody and armed with HER2Bi. In 3+3 dose escalation design, groups of 3 patients received 5, 10, 20, or 40 × 109 armed ATC (aATC) per infusion. RESULTS There were no dose limiting toxicities and the MTD was not defined. It was technically feasible to grow 160 × 109 ATC from a single leukapheresis. aATC persisted in the blood for weeks and trafficked to tumors. Infusions of aATC induced anti-breast cancer responses and increases in immunokines. At 14.5 weeks after enrollment, 13 of 22 (59.1%) evaluable patients had stable disease and 9 of 22 (40.9%) had progressive disease. The median OS was 36.2 months for all patients, 57.4 months for HER2 3+ patients, and 27.4 months for HER2 0–2+ patients. CONCLUSIONS Targeting HER2 positive and negative tumors with aATC infusions induced anti-tumor responses, increases in Th1 cytokines and IL-12 serum levels that suggest that aATC infusions vaccinated patients against their own tumors. These results provide a strong rationale for conducting phase II trials.

C-myc is an oncogene that functions both in the stimulation of cell proliferation and in and apoptosis. C-myc elicits its oncogenic activity by causing immortalization, and to a lesser extent the transformation of cells, in addition to several other mechanisms. C-myc may also enhance or reduce the sensitivity of cancer cells to chemotherapy, but how this dual function is controlled is largely unclear. Cyclin D1 (D1) is another oncogene that drives cell cycle progression; it acts as a growth factor sensor to integrate extracellular signals with the cell cycle machinery, though it may also promote apoptosis. C-Myc collaborates with TGFalpha, epidermal growth factor receptor, Ras, PI3K/Akt, and NF-kappaB. in part via coordination in regulation of D1 expression, because D1 is a common downstream effector of these growth pathways. Coordination of c-Myc with D1 or its upstream activators not only accelerates tumor formation, but also may drive tumor progression to a more aggressive phenotype. Because c-Myc may effect immortalization while D1 or its upstream activators elicit transformation, targeting c-myc and D1 may be a good strategy for cancer prevention. Moreover, since D1 imposes chemoresistance on cancer cells, targeting D1 may also be a good strategy for cancer chemotherapy, whereas practicioners should be cautious to downregulate c-myc for chemotherapy, since c-Myc may elicit apoptosis.

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Asthma is a worldwide health problem. Activated T cells (ATCs) in the lung, particularly T helper 2 cells (Th2), are strongly associated with inducing airway inflammatory responses and chemoattraction of inflammatory cells in asthma. Small interfering RNA (siRNA) as a promising anti-sense molecule can specifically silence inflammation related genes in ATCs, however, lack of safe and efficient siRNA delivery systems limits the application of siRNA as a therapeutic molecule in asthma. Here, we designed a novel pulmonary delivery system of siRNA, transferrin-polyethylenimine (Tf-PEI), to selectively deliver siRNA to ATCs in the lung. Tf-PEI polyplexes demonstrated optimal physicochemical properties such as size, distribution, zeta-potential, and siRNA condensation efficiency. Moreover, in vitro studies showed significantly enhanced cellular uptake and gene knockdown mediated by Tf-PEI polyplexes in human primary ATCs. Biodistribution of polyplexes in a murine asthmatic model confirmed that Tf-PEI polyplexes can efficiently and selectively deliver siRNA to ATCs. In conclusion, the present work proves the feasibility to target ATCs in asthma via Tf receptor. This strategy could potentially be used to design an efficient siRNA delivery system for asthma therapy.

Purpose We have previously shown that p90 ribosomal protein S6 kinase 4 (RSK4), an X-linked gene, is highly up-regulated in mammary tumors of MMTV-c-Myc transgenic mice. In this study, we further investigated whether RSK4 inhibits or promotes breast tumor growth and progression. Experimental Design Stable overexpression or small interfering RNA – mediated knockdown of RSK4 was done in the MDA-MB-231cell line. Stable clones were tested for cell proliferation, anchorage-independent growth in soft agar, invasive and metastatic ability of these clones in vitro and tumorigenesis, invasive and metastatic ability in vivo in severe combined immunodeficient mice. Results Here, we show that exogenous expression of RSK4 resulted in decreased cell proliferation and increased accumulation of cells in G0–G1phase, which paralleled with enhanced expression of tumor suppressor genes: retinoblastoma protein, retinobl astoma-associated 46 kDa protein, and p21 protein. Overexpression of RSK4 resulted in reduced colony formation in soft agar and suppressed invasive and migratory activities of MDA-MB-231cells both in vitro and in vivo. Importantly, RSK4-overexpressing cells showed up-regulation of claudin-2 and down-regulation of CXCR4, both of these play roles in invasion and chemotaxis. Conclusions These results indicate that RSK4 expression may limit the oncogenic, invasive, and metastatic potential of breast cancer cells. Anti-invasive and antimetastatic activities of RSK4 may be, in part, due to its regulation of claudin-2. Increased expression of RSK4 in c-Myc-overexpressing cells and a dose-dependent induction of luciferase reporter gene activity suggest that c-Myc may regulate RSK4 expression.

c-Myc is a transcription factor overexpression of which induces mammary cancer in transgenic mice. To explore whether certain microRNAs (mirRNA) mediate c-Myc induced mammary carcinogenesis, we studied mir-RNA expression profile in mammary tumors developed from MMTV-c-myc transgenic mice, and found 50 and 59 mirRNAs showing increased and decreased expression, respectively, compared with lactating mammary glands of wild type mice. Twenty-four of these mirRNAs could be grouped into eight clusters because they had the same chromosomal localizations and might be processed from the same primary RNA transcripts. The increased expression of mir-20a, mir-20b, and mir-9 as well as decreased expression of mir-222 were verified by RT-PCR, real-time RT-PCR, and cDNA sequencing. Moreover, we fortuitously identified a novel non-coding RNA, the level of which was decreased in proliferating mammary glands of MMTV-c-myc mice was further decreased to undetectable level in the mammary tumors. Sequencing of this novel RNA revealed that it was transcribed from a region of mouse chromosome 19 that harbored the metastasis associated lung adenocarcinoma transcript-1 (Malat-1), a non-protein-coding gene. These results suggest that certain mirRNAs and the chromosome 19 derived non-coding RNAs may mediate c-myc induced mammary carcinogenesis.

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