The novel multitargeted tyrosine kinase inhibitor sunitinib is used as an anti-angiogenic agent for the treatment of several types of cancer, including metastatic renal cell carcinoma (RCC). Sunitinib was shown to positively change the immunosuppressive phenotype in RCC patients. In order to improve its antitumor efficacy, and offer strategies for its combination with other approaches, it is critical to fully elucidate its mechanisms of action. We show that sunitinib induces tumor cell apoptosis and growth arrest in RCC tumor cells, which correlates with Stat3 activity inhibition. Sunitinib-mediated direct effects on tumor cells occur regardless of von Hippel-Lindau tumor suppressor gene status and hypoxia-inducible transcription factor-2α levels. Reduction of Stat3 activity enhances sunitinib's antitumor effects, whereas expression of a constitutively-activated Stat3 mutant rescues tumor cell death. Intravital multi-photon microscopy data show that sunitinib induces mouse Renca tumor cell apoptosis in vivo before tumor vasculature collapse. Sunitinib also inhibits Stat3 in Renca tumor-associated myeloid derived suppressor cells (MDSCs), downregulates angiogenic gene expression, and reduces MDSCs and tumor T regulatory cells. These results suggest that Stat3 activity is important for RCC response to sunitinib, and Stat3 inhibition permits sunitinib's direct proapoptotic activity on tumor cells and positive effects on tumor immunologic microenvironment.

Understanding the complexity and dynamics of cancer cells in response to effective therapy requires hypothesis-driven, quantitative, and high-throughput measurement of genes and proteins at both spatial and temporal levels. This study was designed to gain insights into molecular networks underlying the clinical synergy between retinoic acid (RA) and arsenic trioxide (ATO) in acute promyelocytic leukemia (APL), which results in a high-quality disease-free survival in most patients after consolidation with conventional chemotherapy. We have applied an approach integrating cDNA microarray, 2D gel electrophoresis with MS, and methods of computational biology to study the effects on APL cell line NB4 treated with RA, ATO, and the combination of the two agents and collected in a time series. Numerous features were revealed that indicated the coordinated regulation of molecular networks from various aspects of granulocytic differentiation and apoptosis at the transcriptome and proteome levels. These features include an array of transcription factors and cofactors, activation of calcium signaling, stimulation of the IFN pathway, activation of the proteasome system, degradation of the PML-RAR␣ oncoprotein, restoration of the nuclear body, cell-cycle arrest, and gain of apoptotic potential. Hence, this investigation has provided not only a detailed understanding of the combined therapeutic effects of RA͞ATO in APL but also a road map to approach hematopoietic malignancies at the systems level.systems biology ͉ self-organizing map A cute promyelocytic leukemia (APL) is a form of acute myeloid leukemia that responds remarkably to the effect of differentiation-induction by all-trans-retinoic acid and the differentiation͞ apoptosis-inducing effect of arsenic trioxide (ATO). Cytogenetically, a translocation t(15;17)(q22;q21) is found in most APL patients, resulting in the formation of the promyelocytic leukemiaretinoic acid receptor ␣ (PML-RAR␣) fusion gene (1). The chimeric protein encoded by the fusion gene oligomerizes with retinoid-X receptor (RXR) and disrupts the retinoic acid (RA) signal pathway, which is essential for granulocytic differentiation. PML-RAR␣ can also form a homodimer that competes with RAR␣ for binding to the RA-response elements of target genes and binds to the corepressor (CoR) complex with a much higher affinity than does the wild-type RAR␣͞RXR. This change leads to transcriptional repression under physiological concentrations of RA and, thus, blocks cell differentiation. Pharmacological concentrations of RA can convert the PML-RAR␣ fusion protein from a transcription repressor to a transcription activator, resulting in the release of the CoR and the recruitment of a coactivator (CoA) complex. The RA treatment can also trigger degradation of the PML-RAR␣ protein via the ubiquitin͞proteasome (U͞P) pathway and, thus, trigger reassembly of the nuclear body (NB) (2). On the other hand, ATO induces partial differentiation and͞or apoptosis of APL cells in a dose-dependent manner. Importantly, cellular and m...

Erythropoietin (Epo) is a normal constituent of human milk, but the origin and fate of this cytokine in milk are not known. Regarding its origin, we hypothesized that cells of the mammary gland secrete Epo into milk actively and, therefore, that concentrations in milk do not correlate with concentrations in serum. Regarding its fate, we hypothesized that Epo concentrations in milk change with time postpartum and that Epo in milk is protected from digestion in the neonatal gastrointestinal tract. To address these issues, we measured Epo concentrations in 103 milk samples (ELISA), 55 of which were paired with serum. Mammary duct epithelial cells were evaluated as a source of Epo by breast tissue immunohistochemistry and by cell culture. Circulating and milk Epo were compared by Western analysis to detect size differences, possibly reflecting differences in processing. Epo stability in simulated conditions of digestion was evaluated. We observed that milk Epo concentrations increase as a function of duration of breast-feeding and have a negative correlation with serum Epo or milk protein concentration. Mammary duct epithelial cells from breast biopsies of lactating women had marked immunoreactivity to Epo, but such activity was minimal to absent in nonlactating breast tissue. Further evidence that mammary duct epithelia produce Epo was obtained by observing Epo mRNA and protein expression in cultured human mammary epithelial cells. The molecular size of Epo in milk and serum is identical. Recombinant Epo added to human milk or commercial infant formulas was relatively stable in conditions that simulate gastric and small intestinal conditions of newborn infants; however, recombinant Epo added to D 5 W was not protected from digestion. We conclude that Epo concentrations in milk increase as a function of the duration of breast feeding, that Epo is actively secreted into human milk by mammary duct epithelia, and that the Epo within milk is largely protected from digestion. Abbreviations Epo, erythropoietin Epo-R, erythropoietin receptors GI, gastrointestinal HMEC, human mammary epithelial cells rEpo, recombinant erythropoietin Significant Epo concentrations have been measured in human milk (1), but the origin and fate of Epo in milk are not known. Specifically, it is not known whether Epo is secreted actively or passively into milk, whether any Epo-producing cells exist in breast tissue, whether maternal serum Epo concentrations correlate with milk Epo concentrations, or whether milk Epo is processed differently from circulating Epo, resulting in a difference in glycosylation. In addition, it is not known whether Epo concentrates in a particular partition (fore, mid, or hind milk) or phase (aqueous versus lipid) of milk. No information is available regarding the stability of rEpo added to commercially available infant formulas or whether routine storage conditions (freeze/thaw) or pasteurization procedures (heating) degrade Epo.A physiologic role for enteral Epo is likely, as Epo-R are present on mucosal cells of the ...

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BackgroundmTOR signaling pathway and its downstream serine/threonine kinase p70S6k were frequently activated in human cancers. The dysregulation of the mTOR pathway has been found to be a contributing factor of a variety of different cancer. To investigate the role of mTOR signal pathway in the stepwise development of gastric carcinomas, we analyzed the correlations between the mTOR and P70S6K expression and clinic pathological factors and studied its prognostic role in gastric carcinomas.MethodsmTOR and phospho-p70S6K proteins were examined by immunohistochemistry on tissue microarray containing gastric carcinomas (n = 412), adenomas (n = 47) and non-neoplastic mucosa (NNM, n = 197) with a comparison of their expression with clinicopathological parameters of carcinomas.ResultsThere was no difference of mTOR expression between these three tissues (p > 0.05). Cytoplasmic phospho(p)-P706SK was highly expressed in adenoma, compared with ANNMs (p < 0.05), whereas its nuclear expression was lower in gastric carcinomas than gastric adenoma and ANNMs (p < 0.05). These three markers were preferably expressed in the older patients with gastric cancer and intestinal-type carcinoma (p < 0.05). mTOR expression was positively correlated with the cytoplasmic and nuclear expression of p-P70S6K(p < 0.05). Nuclear P70S6K was inversely linked to tumor size, depth of invasion, lymph node metastasis and UICC staging (p < 0.05). Univariate analysis indicated that expression of mTOR and nuclear p-P70S6K was closely linked to favorable prognosis of the carcinoma patients (p < 0.05). Multivariate analysis showed that age, depth of invasion, lymphatic invasion, lymph node metastasis, Lauren's classification and mTOR expression were independent prognostic factors for overall gastric carcinomas (p < 0.05).ConclusionAberrant expression of p-P70S6K possibly contributes to pathogenesis, growth, invasion and metastasis of gastric carcinomas. It was considered as a promising marker to indicate the aggressive behaviors and prognosis of gastric carcinomas.

Abundant evidence has illustrated that long non-coding RNA (lncRNA) plays a vital role in the regulation of tumor development and progression. Most lncRNAs have been proven to have biological and clinical significance in acute myeloid leukemia (AML), but further investigation remains necessary. In this study, we investigated lncRNA NR-104098 in AML and its specific mechanism. The microarray analysis was performed on NB4 cells. Based on the related analysis results, we identified that lncRNA NR-104098 is a suppressor gene that is significantly upregulated in AML cells. LncRNA NR-104098 could inhibit proliferation and induce differentiation in AML cells in vitro and also play main role in the mouse xenografts. Mechanically, it was confirmed that lncRNA NR-104098 may effectively inhibit EZH2 transcription by directly binding to E2F1 and recruiting E2F1 to the EZH2 promoter. In addition, ATPR can significantly increase the expression of lncRNA NR-104098, whereas knocking down NR104098 can inhibit the inhibitory effect of ATPR on the proliferation and induction differentiation of AML cells. Taken together, these results lead to deeper insight into the mechanism of ATPR-induced AML differentiation and prevent proliferation by inhibiting EZH2 on the transcriptional level.

Human milk contains substantial quantities of G-CSF. G-CSF-R are abundant on villus enterocytes, and specific proteins associated with G-CSF-R signaling are present in these cells.

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