The TGF-beta signaling pathway has a complex role in regulating mammary carcinogenesis. Here we demonstrate that the type III TGF-beta receptor (TbetaRIII, or betaglycan), a ubiquitously expressed TGF-beta coreceptor, regulated breast cancer progression and metastasis. Most human breast cancers lost TbetaRIII expression, with loss of heterozygosity of the TGFBR3 gene locus correlating with decreased TbetaRIII expression. TbetaRIII expression decreased during breast cancer progression, and low TbetaRIII levels predicted decreased recurrence-free survival in breast cancer patients. Restoring TbetaRIII expression in breast cancer cells dramatically inhibited tumor invasiveness in vitro and tumor invasion, angiogenesis, and metastasis in vivo. TbetaRIII appeared to inhibit tumor invasion by undergoing ectodomain shedding and producing soluble TbetaRIII, which binds and sequesters TGF-beta to decrease TGF-beta signaling and reduce breast cancer cell invasion and tumor-induced angiogenesis. Our results indicate that loss of TbetaRIII through allelic imbalance is a frequent genetic event during human breast cancer development that increases metastatic potential.

Chidamide represents a novel oral benzamide class of HDAC inhibitor with significant single-agent activity and manageable toxicity in relapsed or refractory PTCL, and provides a much needed treatment option in this indication in China. Results led to China Food and Drug Administration approval of chidamide in this indication.

The results presented in this study provide evidence that chidamide has potential applicability for the treatment of a variety of tumor types, either as a single agent or in combination therapies.

Purpose We sought to determine whether PI3K pathway mutation or activation state and rapamycin-induced feedback-loop activation of Akt is associated with rapamycin sensitivity or resistance. Experimental Design Cancer cell lines were tested for rapamycin-sensitivity, Akt phosphorylation and mTOR target inhibition. Mice injected with breast or neuroendocrine cancer cells and patients with neuroendocrine tumor (NET) were treated with rapalogs, and Akt phosphorylation was assessed. Results 31 cell lines were rapamycin-sensitive (RS) and 12 were relatively rapamycin-resistant (RR; IC50>100 nM). Cells with PIK3CA and/or PTEN mutations were more likely to be RS (p=0.0123). Akt phosphorylation (S473 and T308) was significantly higher in RS cells (p<0.0001). Rapamycin led to a significantly greater pathway inhibition and greater increase in p-Akt T308 (p<0.0001) and p-Akt S473 (p=0.0009) in RS cells. Rapamycin and everolimus significantly increased Akt phosphorylation but inhibited growth in an in vivo NET model (BON). In patients with NETs treated with everolimus and octreotide, progression-free survival correlated with p-Akt T308 in pretreatment (R=0.4762, p=0.0533) and on-treatment tumor biopsies (R=0.6041, p=0.0102). Patients who had a documented partial response were more likely to have an increase in p-Akt T308 with treatment compared to non-responders (p=0.0146). Conclusion PIK3CA/PTEN genomic aberrations and high p-Akt levels are associated with rapamycin sensitivity in vitro. Rapamycin-mediated Akt activation is greater in RS cells, with a similar observation in patients with clinical responses on exploratory biomarker analysis; thus feedback-loop activation of Akt is not a marker of resistance but rather may function as an indicator of rapamycin activity.

The transforming growth factor-␤ (TGF-␤) signaling pathway is an essential regulator of cellular processes, including proliferation, differentiation, migration, and cell survival. During hematopoiesis, the TGF-␤ signaling pathway is a potent negative regulator of proliferation while stimulating differentiation and apoptosis when appropriate. In hematologic malignancies, including leukemias, myeloproliferative disorders, lymphomas, and multiple myeloma, resistance to these homeostatic effects of TGF-␤ develops. Mechanisms for this resistance include mutation or deletion of members of the TGF-␤ signaling pathway and disruption of the pathway by oncoproteins. These alterations define a tumor suppressor role for the TGF-␤ pathway in human hematologic malignancies. On the other hand, elevated levels of TGF-␤ can promote myelofibrosis and the pathogenesis of