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Docetaxel-based chemotherapy is the standard first-line therapy in metastatic castration-resistant prostate cancer (CRPC). However, most patients eventually develop resistance to this treatment. In this study, we aimed to identify key molecular genes and networks associated with docetaxel resistance in two models of docetaxel-resistant CRPC cell lines and to test for the most differentially expressed genes in tumor samples from patients with CRPC. DU-145 and PC-3 cells were converted to docetaxel-resistant cells, DU-145R and PC-3R, respectively. Whole-genome arrays were used to compare global gene expression between these four cell lines. Results showed differential expression of 243 genes (P < 0.05, Bonferroni-adjusted P values and log ratio > 1.2) that were common to DU-145R and PC-3R cells. These genes were involved in cell processes like growth, development, death, proliferation, movement, and gene expression. Genes and networks commonly deregulated in both DU-145R and PC-3R cells were studied by Ingenuity Pathways Analysis. Exposing parental cells to TGFB1 increased their survival in the presence of docetaxel, suggesting a role of the TGF-β superfamily in conferring drug resistance. Changes in expression of 18 selected genes were validated by real-time quantitative reverse transcriptase PCR in all four cell lines and tested in a set of 11 FFPE and five optimal cutting temperature tumor samples. Analysis in patients showed a noteworthy downexpression of CDH1 and IFIH1, among others, in docetaxel-resistant tumors. This exploratory analysis provides information about potential gene and network involvement in docetaxel resistance in CRPC. Further clinical validation of these results is needed to develop targeted therapies in patients with CRPC that can circumvent such resistance to treatment. Mol Cancer Ther; 11(2); 329–39. ©2011 AACR.

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Powerpoint file containing Supplementary Figures 1, 2, 3, 4, 5, 6 and 7

Purpose: ABTL0812 is a novel first-in-class, small molecule which showed antiproliferative effect on tumor cells in phenotypic assays. Here we describe the mechanism of action of this antitumor drug, which is currently in clinical development.Experimental Design: We investigated the effect of ABTL0812 on cancer cell death, proliferation, and modulation of intracellular signaling pathways, using human lung (A549) and pancreatic (MiaPaCa-2) cancer cells and tumor xenografts. To identify cellular targets, we performed in silico high-throughput screening comparing ABTL0812 chemical structure against ChEMBL15 database.Results: ABTL0812 inhibited Akt/mTORC1 axis, resulting in impaired cancer cell proliferation and autophagy-mediated cell death. In silico screening led us to identify PPARs, PPARα and PPARγ as the cellular targets of ABTL0812. We showed that ABTL0812 activates both PPAR receptors, resulting in upregulation of Tribbles-3 pseudokinase (TRIB3) gene expression. Upregulated TRIB3 binds cellular Akt, preventing its activation by upstream kinases, resulting in Akt inhibition and suppression of the Akt/mTORC1 axis. Pharmacologic inhibition of PPARα/γ or TRIB3 silencing prevented ABTL0812-induced cell death. ABTL0812 treatment induced Akt inhibition in cancer cells, tumor xenografts, and peripheral blood mononuclear cells from patients enrolled in phase I/Ib first-in-human clinical trial.Conclusions: ABTL0812 has a unique and novel mechanism of action, that defines a new and drugable cellular route that links PPARs to Akt/mTORC1 axis, where TRIB3 pseudokinase plays a central role. Activation of this route (PPARα/γ-TRIB3-Akt-mTORC1) leads to autophagy-mediated cancer cell death. Given the low toxicity and high tolerability of ABTL0812, our results support further development of ABTL0812 as a promising anticancer therapy. Clin Cancer Res; 22(10); 2508–19. ©2015 AACR.

Supplementary Materials and Methods

List of antibodies used in this work

PDF file, 12332K, Supplementary Figure S1. Expression of NK-1R, NK-2R and SP in normal mammary epithelium. Supplementary Figure S2. Transactivation of HER2 by human tachykinins. Supplementary Figure S3. Dose-response effect of SP on HER2 activation. Supplementary Figure S4. Contribution of HER2 signaling to SP-induced MAPK activation. Supplementary Figure S5. Representative images of NK-1R immunohistochemistry in the tumors used for primary cultures. Supplementary Figure S6. Activation of HER2 under SP treatment in each primary culture derived from 19 primary breast tumors. Supplementary Figure S7. Overexpression of NK-1R in BC cells. Supplementary Figure S8. Mitotic index for the MDA-MB-231 and MDA-MB-453 xenograft tumors growth under the continuous exposure to SP. Supplementary Figure S9. Immunohistochemical analysis of the xenograft tumors treated with the NK-1R inhibitor L-733,060. Supplementary Figure S10. Acute and chronic effects of SP on cellular responses to anti-HER2 and anti-EGFR therapies. Supplementary Table S1. Statistical analysis for the correlation of NK-1R, NK-2R and SP expression levels. Supplementary Table S2. Statistical analysis for the correlation of NK-1R, NK-2R and SP expression levels. Supplementary Table S3. Clinical information of the cohort used to investigate the levels of circulating SP in healthy donors and breast cancer patients. Supplementary Table S4. Histopathologic information of the samples used Supplementary Table S5. IC50 obtained in the drug-response studies and combination index.

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Background Following the functional and physicochemical characterization of a proposed biosimilar, comparative clinical studies help to confirm biosimilarity by demonstrating similar safety and efficacy to the reference product in a sensitive patient population. Patients and methods LA-EP2006 is a proposed biosimilar that has been developed for pegfilgrastim, a long-acting form of granulocyte colony-stimulating factor for the prevention of neutropenia. The current analysis reports data pooled from two independent, multinational, prospective, randomized, controlled, double-blind phase III studies of similar design comparing the safety and efficacy of reference pegfilgrastim with LA-EP2006 in patients with breast cancer receiving myelotoxic (neo)adjuvant TAC (docetaxel, doxorubicin, and cyclophosphamide) chemotherapy and requiring granulocyte colony-stimulating factor. Results A total of 624 patients were randomized in the PROTECT-1 and PROTECT-2 studies (NCT01735175; NCT01516736) (LA-EP2006: n = 314; reference: n = 310). Baseline characteristics of patients were well balanced across treatment groups. The primary end point, mean duration of severe neutropenia in the first chemotherapy cycle was similar in both the LA-EP2006 and reference groups (1.05 ± 1.055 days versus 1.01 ± 0.958 days), with a treatment difference of − 0.04 days [95% confidence interval (CI): −0.19 to 0.11] that met the equivalence criteria (the 95% CI were within the defined margin of ±1 day). Secondary end points, such as the nadir of absolute neutrophil count and the incidence of febrile neutropenia, were also similar between LA-EP2006 and reference pegfilgrastim. The safety and tolerability profile of LA-EP2006 was similar to that observed with reference pegfilgrastim, and there were no reports of neutralizing antibodies. Conclusions This pooled analysis confirms, as a part of totality of evidence approach, that the proposed biosimilar pegfilgrastim LA-EP2006 has a comparable efficacy and safety profile to reference pegfilgrastim in patients with breast cancer receiving TAC chemotherapy. Clinical trial numbers NCT01735175 and NCT01516736.

Histamine receptor 1 (HRH1) belongs to the rhodopsin-like G-protein-coupled receptor family. Its activation by histamine triggers cell proliferation, embryonic development, and tumor growth. We recently established that HRH1 is up-regulated in basal and human epidermal growth factor receptor 2 (HER2)-enriched human breast tumors and that its expression correlates with a worse prognosis. Nevertheless, the functional role of HRH1 in basal and HER2-targeted therapy-resistant breast cancer (BC) progression has not yet been addressed. Using terfenadine, a selective chemical inhibitor of HRH1, we showed that the inhibition of HRH1 activity in basal BC cells leads to sub-G0 cell accumulation, suppresses proliferation, promotes cell motility and triggers the activation of extracellular signal-regulated kinase (ERK) signaling, initiating the mitochondrial apoptotic pathway. Furthermore, HER2-targeted therapy-resistant cells express higher levels of HRH1 and are more sensitive to terfenadine treatment. Moreover, in vivo experiments showed that terfenadine therapy reduced the tumor growth of basal and trastuzumab-resistant BC cells. In conclusion, our results suggest that targeting HRH1 is a promising new clinical approach to consider that could enhance the effectiveness of current therapeutic treatment in patients with basal and BC tumors resistant to HER2-targeted therapies.

NK1 is a tachykinin receptor highly relevant to tumorigenesis and metastasis development in breast cancer and other carcinomas. Despite the substantial efforts done to develop potent NK1 receptor antagonists, none of these antagonists had shown good antitumor activity in clinical trials. Now, we have tested the effect of inhibition of the neuropeptide Substance P (SP), a NK1 ligand, as a potential therapeutic approach in cancer. We found that the inhibition of SP with antibodies strongly inhibit cell growth and induce apoptosis in breast, colon, and prostate cancer cell lines. These effects were accompained by a decrease in the mitogen-activated kinase singaling pathway. Interestingly, in some cell lines SP abrogation decreased the steady state of Her2 and EGFR, suggesting that SP-mediated signaling is important for the basal activity of these ErbB receptors. In consequence, we observed a blockade of the cell cycle progression and the inhibition of several cell cycle-related proteins including mTOR. SP inhibition also induced cell death in cell lines resistant to Lapatinib and Trastuzumab that have increased levels of active Her2, suggesting that this therapeutic approach could be also effective for those cancers resistant to current anti-ErbB therapies. Thus, we propose a new therapeutic strategy for those cancers that express NK1 receptor and/or other tachykinin receptors, based in the immuno-blockade of the neuropeptide SP.

G protein-coupled receptors (GPCRs) comprise a large family of membrane receptors involved in signal transduction. These receptors are linked to a variety of physiological and biological processes such as regulation of neurotransmission, growth, cell differentiation and oncogenesis among others. Some of the effects of GPCRs are known to be mediated by the activation of MAPK pathways. Several GPCRs are also able to transactivate receptors with tyrosine kinase activity (TKR) such as EGFR and HER2 and thus to control DNA synthesis and cell proliferation. The interaction between these receptors not only plays an important physiological role but its disregulation can induce pathological states such as cancer. For this reason, the crosstalk between these two types of receptors can be considered a possible mechanism for cell transformation, tumor progression, reactivation of the metastatic disease, and the acquisition of resistance to therapies targeting TKR receptors. The transactivation of some TKRs by GPCRs is related to the lost of response of TKRs to inhibitors of TK activity, mainly by the activation of the c-Src protein which can directly phosphorylate and activate the cytoplasmic domain of a TKR. For these reason, the dual inhibition of GPCRs and TKRs in some types of cancer has been proposed as a better strategy to kill tumor cells. Increased understanding of the mechanisms that interconnect the two pathways regulated by GPCRs and TKRs may facilitate the design of new therapeutic strategies.

Insulin-like growth factor-I (IGF-I) is thought to have antiapoptotic and mitogenic properties in colorectal cancer, whereas IGF-binding protein-3 (IGFBP-3) seems to exert a pro-apoptotic effect. Additionally, matrix metalloproteinase-7 (MMP-7), an enzyme with in vitro ability to degrade IGFBP-3, has been shown to be a prognostic factor in advanced colorectal cancer (ACRC). We studied whether chemotherapy treatment for ACRC modulates IGF-I, IGFBP-3, and MMP-7 serum levels. In 41 patients undergoing first-line therapy for ACRC, serum levels of IGF-I, IGFBP-3, and MMP-7 were measured with immunoassays at baseline and every 3 months until progressive disease, or a maximum of five determinations, during a chemotherapy regimen of either FOLFOX or FOLFIRI therapies. Associations were assessed for paired samples, using t-test or Wilcoxon ranks test depending on normality of the variable, verified with Shapiro-Wilk test. An average of four extractions (range 3–5) were done, for a total of 157 determinations. Mean pretreatment values of IGF-I, IGFBP-3, and MMP-7 were 83 (95% CI, 73–92) ng/ml, 2372 (95% CI, 2121–2623) ng/ml, and 10.6 (95% CI, 7.21–13.98) ng/ml respectively. No significant changes in IGF-I were found, but a significant increase in IGFBP-3 serum concentrations was observed during or after chemotherapy treatment without progressive disease, compared with basal levels (PP

The nervous system is now recognized to be a relevant component of the tumor microenvironment. Receptors for neuropeptides and neurotransmitters have been identified in breast cancer. However, very little is known about the role of neurogenes in regulating breast cancer progression. Our purpose was to identify neurogenes associated with breast cancer tumorigenesis with a potential to be used as biomarker and/or targets for treatment. We used three databases of human genes: GeneGo, GeneCards and Eugenes to generate a list of 1266 relevant neurogenes. Then we used bioinformatics tools to interrogate two published breast cancer databases SAGE and MicMa (n=96) and generated a list of 7 neurogenes that are differentially express among breast cancer subtypes. The clinical potential was further investigated using the GOBO database (n=1881). We identified 6 neurogenes that are differentially expressed among breast cancer subtypes and whose expression correlates with prognosis. Histamine receptor1 (HRH1), neuropilin2 (NRP2), ephrin-B1 (EFNB1), neural growth factor receptor (NGFR) and amyloid precursor protein (APP) were differentially overexpressed in basal and HER2-enriched tumor samples and syntaxin 1A (STX1A) was overexpressed in HER2-enriched and luminal B tumors. Analysis of HRH1, NRP2, and STX1A expression using the GOBO database showed that their expression significantly correlated with a shorter overall survival (p < 0.0001) and distant metastasis-free survival (p < 0.0001). In contrast, elevated co-expression of NGFR, EFNB1 and APP was associated with longer overall (p < 0.0001) and metastasis-free survival (p < 0.0001). We propose that HRH1, NRP2, and STX1A can be used as prognostic biomarkers and therapeutic targets for basal and HER2-enriched breast cancer subtypes.

The enumeration of circulating tumor cells (CTCs) in peripheral blood correlates with clinical outcome in castration-resistant prostate cancer (CRPC). We analyzed the molecular profiling of peripheral blood from 43 metastatic CRPC patients with known CTC content in order to identify genes that may be related to prostate cancer progression. Global gene expression analysis identified the differential expression of 282 genes between samples with ≥5 CTCs vs

Hypoxia is a hallmark of solid tumors that drives malignant progression by altering epigenetic controls. In breast tumors, aberrant DNA methylation is a prevalent epigenetic feature associated with increased risk of metastasis and poor prognosis. However, the mechanism by which hypoxia alters DNA methylation or other epigenetic controls that promote breast malignancy remains poorly understood. We discovered that hypoxia deregulates TET1 and TET3, the enzymes that catalyze conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), thereby leading to breast tumor–initiating cell (BTIC) properties. TET1/3 and 5hmC levels were closely associated with tumor hypoxia, tumor malignancy, and poor prognosis in breast cancer patients. Mechanistic investigations showed that hypoxia leads to genome-wide changes in DNA hydroxymethylation associated with upregulation of TNFα expression and activation of its downstream p38–MAPK effector pathway. Coordinate functions of TET1 and TET3 were also required to activate TNFα–p38–MAPK signaling as a response to hypoxia. Our results reveal how signal transduction through the TET–TNFα–p38–MAPK signaling axis is required for the acquisition of BTIC characteristics and tumorigenicity in vitro and in vivo, with potential implications for how to eradicate BTIC as a therapeutic strategy. Cancer Res; 75(18); 3912–24. ©2015 AACR.

The nuclear factor (NF)-kappaB system is a promising anticancer target due to its role in oncogenesis and chemoresistance in preclinical models. To provide evidence in a clinical setting on the role of NF-kappaB in breast cancer, we aimed to study the value of basal NF-kappaB/p65 in predicting resistance to neoadjuvant chemotherapy, and to characterise the pharmacodynamic changes in NF-kappaB/p65 expression following chemotherapy in patients with locally advanced breast cancer. Pre- and post-chemotherapy tumour specimens from 51 breast cancer patients treated with anthracycline- and/or taxane-containing neoadjuvant chemotherapy were assayed by immunohistochemistry for NF-kappaB/p65 subcellular expression. We studied NF-kappaB/p65, a well-characterised member of the NF-kappaB family that undergoes nuclear translocation when NF-kappaB is activated. Activation of NF-kappaB (i.e. nuclear NF-kappaB/p65 staining in pre-therapy specimens) was linked to chemoresistance. Patients with NF-kappaB/p65 nuclear staining in pre-treatment samples had a 20% clinical response rate, while patients with undetected nuclear staining had a 91% response rate to chemotherapy (P = 0.002). Notably, four patients achieved a complete histological response and none of them had pre-treatment NF-kappaB/p65 nuclear staining. Moreover, the number of patients with NF-kappaB/p65 activation increased after chemotherapy exposure. It is concluded that NF-kappaB/p65 activation assayed by immunohistochemistry is a predictive factor of resistance to neoadjuvant chemotherapy in breast cancer patients. Moreover, NF-kappaB activation was inducible following chemotherapy in a proportion of breast cancer patients. These novel clinical findings strengthen the rationale for the use of NF-kappaB inhibitors to prevent or overcome chemoresistance in breast cancer.

Hematopoiesis is maintained by "fine-tuned" regulation among cytokines, neuropeptides, neurotransmitters, and neurotrophic factors. Neurotransmitters, derived from PPT-I exert immune and hematopoietic regulation. PPT-I is also expressed locally in bone marrow (BM) stromal cells. PPT-I peptides induce the production of cytokines in BM cells, resulting in regulation of both committed progenitors (CFU-GM) and primitive hematopoietic progenitors (CAFC). Both types of progenitors are regulated differently by the two major PPT-I peptides, SP and NK-A. Endopeptidases, present in BM cells, can digest SP to produce SP(1-4) and SP(4-11). In this study, we investigated the hematopoietic effects of these fragments on CFU-GM and CAFC. Similar to the two major intact PPT-I peptides (SP and NK-A), we observed different hematopoietic effects by SP(1-4) and SP(4-11). Whereas SP(1-4) exerted inhibitory effects on CFU-GM and CAFC, SP(4-11) mediated stimulatory effects. Similar to NK-A, the inhibitory effects of SP(1-4) can be partly explained by the induction of suppressive cytokines (TGF-beta, TNF-alpha, and INF-gamma). Use of antagonists and screening of a dodecapeptide expression library determined that the effects of SP(1-4) were mediated by NK-1. These results show that PPT-I peptides and their endopeptidase-derived fragments may add to the fine-tuned regulation on hematopoiesis. Furthermore, PPT-I may be exerting autoregulation to protect hematopoietic stem cells. These studies have relevance to stem cell protection and BM transplant.

The neurokinin 1 receptor (NK-1R) is the main receptor for the tachykinin family of peptides. Substance P (SP) is the major mammalian ligand and the one with the highest affinity. SP is associated with multiple processes: hematopoiesis, wound healing, microvasculature permeability, neurogenic inflammation, leukocyte trafficking, and cell survival. It is also considered a mitogen, and it has been associated with tumorigenesis and metastasis. Tachykinins and their receptors are widely expressed in various human systems such as the nervous, cardiovascular, genitourinary, and immune system. Particularly, NK-1R is found in the nervous system and in peripheral tissues and are involved in cellular responses such as pain transmission, endocrine and paracrine secretion, vasodilation, and modulation of cell proliferation. It also acts as a neuromodulator contributing to brain homeostasis and to sensory neuronal transmission associated with depression, stress, anxiety, and emesis. NK-1R and SP are present in brain regions involved in the vomiting reflex (the nucleus tractus solitarius and the area postrema). This anatomical localization has led to the successful clinical development of antagonists against NK-1R in the treatment of chemotherapy-induced nausea and vomiting (CINV). The first of these antagonists, aprepitant (oral administration) and fosaprepitant (intravenous administration), are prescribed for high and moderate emesis.

The ErbB tyrosine kinase receptor family comprises 4 receptors (HER1 [EGFR/ErbB1], HER2 [ErbB2], HER3 [ErbB3] and HER4 [ErbB4]), and at least 10 ligands. Pre-clinical and clincial studies have indicated that members of this family have important roles in breast cancer development and progression, and which leads to the concept of targeting ErbB receptors as a promising treatment strategy. Trastuzumab, an anti-HER2 antibody, provided the first definitive evidence for the clinical efficacy of targeting an ErbB receptor in patients with breast cancer. Over the past 5 years, much interest has been generated as a result of the development of orally-administered ErbB tyrosine kinase receptor inhibitors. Pre-clinical and early clinical studies with these agents are reviewed here.

Neurokinin 1 (NK-1) is a member of seven transmembrane G protein-coupled receptors. NK-1 interacts with peptides belonging to the tachykinin family and showed preference for substance P (SP). NK-1 is induced in bone marrow (BM) stroma. NK-1-SP interactions could lead to changes in the functions of lymphohematopoietic stem cell (LHSC). This report describes the cloning and characterization of a cDNA clone isolated after screening of three cDNA libraries with an NK-1-specific probe. Based on its expression, the cDNA clone was designated hematopoietic growth factor inducible neurokinin-1 type (HGFIN). Computational analyses predicted that HGFIN is transmembrane with the carboxyl terminal extracellular. Proteomic studies with purified HGFIN and SP showed noncovalent interactions. HGFIN-SP interactions were supported by transient expression of HGFIN in CHO cells. Transient expression of HGFIN in unstimulated BM fibroblasts led to the induction of endogenous NK-1. Since NK-1 expression in BM fibroblasts requires cell stimulation, these studies suggest that there might be intracellular crosstalk between NK-1 and HGFIN. Northern analyses with total RNA from different BM cell subsets showed that HGFIN was preferentially expressed in differentiated cells. This suggests that HGFIN might be involved in the maturation of LHSC. HGFIN was detected in several other tissues, but not in brain where NK-1 is constitutively expressed.

PURPOSE: To evaluate the clinical significance of the detection of circulating melanoma cells in patients treated with adjuvant interferon and to determine their potential value as a marker of interferon response. PATIENTS AND METHODS: We prospectively analyzed 616 peripheral-blood samples from 120 melanoma patients with stage IIA (n = 33), IIB (n = 22), III (n = 50), or IV (surgically resected) (n = 15) disease receiving adjuvant interferon alfa-2b therapy. Tyrosinase mRNA was assayed by reverse transcriptase polymerase chain reaction (RT-PCR) as a marker of circulating melanoma cells before the start of interferon and every 2 to 3 months thereafter. RESULTS: With a median follow-up time of 32.3 months (range, 7.1 to 77.5 months), 47 patients (39.8%) relapsed and 31 (26%) died. During adjuvant interferon treatment, 76 patients (64%) had undetected circulating melanoma cells and 44 patients (36%) had a positive RT-PCR result in at least one sample. Actuarial 5-year disease-free survival was 62% in patients with persistently negative RT-PCR during interferon treatment and 38% for patients with positive RT-PCR during interferon (P = .02). Actuarial 5-year overall survival was 75% and 50%, respectively (P = .03). CONCLUSION: Patients with melanoma and tyrosinase mRNA detected in the blood during adjuvant interferon therapy had a worse prognosis compared with patients with undetected tyrosinase mRNA during treatment. Further investigation into the detection of circulating melanoma cells as a surrogate marker of response to adjuvant interferon therapy is warranted.

Preprotachykinin-I gene (PPT-I) encodes several peptides with organ-specific functions that link the neuroendocrine-immune-hemopoietic axis. We cloned upstream of the initiation site of human PPT-I promoter and identified consensus sequences for two cAMP response elements (CRE). PPT-I is induced by cytokines including those that signal through the cAMP pathway. Therefore, we studied the role of the two CRE in IL-1α and stem cell factor (SCF) stimulation of bone marrow stroma because both cytokines induce endogenous PPT-I in these cells and activate the cAMP pathway. Furthermore, bone marrow stroma expresses the transcription factors regulated by the cAMP pathways such as the repressor (ICERIIγ) and activator (CREMτ). Mutagenesis of the two CRE and/or cotransfection with vectors that express ICERIIγ or CREMτ indicated that the two CRE have major roles in PPT-I expression. The two CRE are also required for optimal promoter activity by SCF and IL-1α. A particular cytokine could concomitantly induce PPT-I and the high affinity G protein-coupled receptor for PPT-I peptides, NK-1R. We showed that SCF, a representative cytokine, induced PPT-I and NK-1R leading to autocrine and/or paracrine cell activation. Because NK-1R activates cAMP through the G protein, the results suggest that the presence of CRE sequences within PPT-I promoter could be important in the regulation of PPT-I expression by cytokines, irrespective of their ability to signal through cAMP. As PPT-I is implicated in hemopoietic regulation, immune responses, breast cancer, and other neural functions, these studies add to the basic biology of these processes and could provide targets for drug development.

Neuropeptides are implicated in many tumors, breast cancer (BC) included. Preprotachykinin-I ( PPT-I ) encodes multiple neuropeptides with pleiotropic functions such as neurotransmission, immune/hematopoietic modulation, angiogenesis, and mitogenesis. PPT-I is constitutively expressed in some tumors. In this study, we investigated a role for PPT-I and its receptors, neurokinin-1 ( NK-1 ) and NK-2 , in BC by using quantitative reverse transcription–PCR, ELISA, and in situ hybridization. Compared with normal mammary epithelial cells ( n = 2) and benign breast biopsies ( n = 21), BC cell lines ( n = 7) and malignant breast biopsies ( n = 25) showed increased expression of PPT-I and NK-1 . NK-2 levels were high in normal and malignant cells. Specific NK-1 and NK-2 antagonists inhibited BC cell proliferation, suggesting autocrine and/or intercrine stimulation of BC cells by PPT-I peptides. NK-2 showed no effect on the proliferation of normal cells but mediated the proliferation of BC cells. Cytosolic extracts from malignant BC cells enhanced PPT-I translation whereas extracts from normal mammary epithelial cells caused no change. These enhancing effects may be protein-specific because a similar increase was observed for IL-6 translation and no effect was observed for IL-1α and stem cell factor. The data suggest that PPT-I peptides and their receptors may be important in BC development. Considering that PPT-I peptides are hematopoietic modulators, these results could be extended to understand early integration of BC cells in the bone marrow, a preferred site of metastasis. Molecular signaling transduced by PPT-I peptides and the mechanism that enhances translation of PPT-I mRNA could lead to innovative strategies for BC treatments and metastasis.

ERBB receptor transmodulation by heterologous G-protein–coupled receptors (GPCR) generates functional diversity in signal transduction. Tachykinins are neuropeptides and proinflammatory cytokines that promote cell survival and cancer progression by activating several GPCRs. In this work, we found that the pain-associated tachykinin Substance P (SP) contributes to persistent transmodulation of the ERBB receptors, EGFR and HER2, in breast cancer, acting to enhance malignancy and therapeutic resistance. SP and its high-affinity receptor NK-1R were highly expressed in HER2+ primary breast tumors (relative to the luminal and triple-negative subtypes) and were overall correlated with poor prognosis factors. In breast cancer cell lines and primary cultures derived from breast cancer samples, we found that SP could activate HER2. Conversely, RNA interference-mediated attenuation of NK-1R, or its chemical inhibition, or suppression of overall GPCR-mediated signaling, all strongly decreased steady-state expression of EGFR and HER2, establishing that their basal activity relied upon transdirectional activation by GPCR. Thus, SP exposure affected cellular responses to anti-ERBB therapies. Our work reveals an important oncogenic cooperation between NK-1R and HER2, thereby adding a novel link between inflammation and cancer progression that may be targetable by SP antagonists that have been clinically explored. Cancer Res; 73(21); 6424–34. ©2013 AACR.

Background: ABTL0812 is a first-in-class antitumor drug whose mechanism of action relies on the inhibition of PI3K/Akt/mTOR (PAM) pathway by upregulation of TRIB3 levels, an endogenous inhibitor of Akt activity that prevents Akt phosphorylation. Preclinical studies showed good efficacy of ABTL0812 in xenograft models with high safety margin. Here we describe the First-in-Human (FiH) Phase I/Ib clinical trial of ABTL0812 in patients with advanced solid tumors (NCT02201823). Methods: ABTL0812 was dosed daily, by the oral route, in 28-day cycles. The study included a 4-cohort dose escalation, in a 3+3 dose escalating design, followed by an expansion cohort. The trial objectives were to determine safety and tolerability, to evaluate signs of efficacy, to determine drug pharmacokinetics (PK) in plasma and to analyze inhibition of Akt phosphorylation in platelets by MSD® as pharmacodynamic (PD) biomarker. Pretreatment tumor biopsies were analyzed by next generation sequencing to identify mutations in a panel of 50 cancer-related genes. Results: Fifteen patients were recruited in the escalation part and 14 patients in the expansion cohort (February 2014 to May 2015). No dose-limiting-toxicities were detected and the recommended Phase II was 1300 mg tid based on PK/PD modeling. The median number of previous chemotherapy lines was 2 (range 0-11). The profile of ABTL0812 grade 1-2 related adverse events (AEs) included asthenia, nausea/vomiting and throat burning (34%, 31% and 24% of patients, respectively). Only one case of grade 3-4 AE (elevated hepatic enzymes) appeared. ABTL0812 half-life was short (3-5 h), which supported the increase in the administration schedule from once to twice and finally to three times a day. Biomarker analysis showed inhibition of Akt phosphorylation with increasing doses, with average 90% inhibition in the expansion cohort; furthermore it correlated with C-trough plasma levels. Five patients had stable disease (SD) for at least 16 weeks: 1 endometrial cancer (62 weeks), 1 cholangiocarcinoma (35 weeks, ongoing on Sep 15th, 2015), 2 colorectal cancer (28 and 22 weeks) and 1 lung adenocarcinoma (16 weeks). The median time to progression in the expansion cohort was 11 weeks (range 1-≥35 weeks). Interestingly, the tumor biopsy from the patient with endometrial cancer had activating mutations in Akt1 (E17K) and PIK3CA (R88Q). The tumor from the patient with colorectal cancer (28 weeks SD) showed deleterious mutations in TP53 (R248W) and APC (Q1469Ter). None of these samples included major mutations in Ras. Conclusions: ABTL0812 is a PAM pathway inhibitor acting by a novel mechanism of action that involves upregulation of TRIB3 levels. The FiH Phase I/Ib study in patients with advanced solid tumors showed excellent tolerability and safety profile and demonstrated dose-dependent inhibition of Akt phosphorylation. ABTL0812 treatment induced several long term disease stabilizations (5/29), being the best responder a patient with endometrial cancer (68 weeks) with activating mutations in Akt1 and PIK3CA. Based on these data, a Phase II clinical trial in patients with endometrial cancer is planned. Citation Format: Laura Vidal, Lydia Gaba, Ivan Victoria, Marta Gil-Martin, Berta Laquente, Marc Cortal, Merce Brunet, Pilar Paredes, Mariana Gomez-Ferreria, Jose Alfon, Carles Domenech, Pedro Gascon. First-in-Human Clinical Trial of ABTL0812, a Compound that Inhibits PI3K/Akt/mTOR Pathway by Upregulating TRIB3, in Patients with Advanced Solid Tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr LB-C18.

Docetaxel-based chemotherapy is the standard first-line therapy in metastatic castration-resistant prostate cancer (CRPC). However, most patients eventually develop resistance to this treatment. In this study, we aimed to identify key molecular genes and networks associated with docetaxel resistance in two models of docetaxel-resistant CRPC cell lines and to test for the most differentially expressed genes in tumor samples from patients with CRPC. DU-145 and PC-3 cells were converted to docetaxel-resistant cells, DU-145R and PC-3R, respectively. Whole-genome arrays were used to compare global gene expression between these four cell lines. Results showed differential expression of 243 genes (P < 0.05, Bonferroni-adjusted P values and log ratio > 1.2) that were common to DU-145R and PC-3R cells. These genes were involved in cell processes like growth, development, death, proliferation, movement, and gene expression. Genes and networks commonly deregulated in both DU-145R and PC-3R cells were studied by Ingenuity Pathways Analysis. Exposing parental cells to TGFB1 increased their survival in the presence of docetaxel, suggesting a role of the TGF-β superfamily in conferring drug resistance. Changes in expression of 18 selected genes were validated by real-time quantitative reverse transcriptase PCR in all four cell lines and tested in a set of 11 FFPE and five optimal cutting temperature tumor samples. Analysis in patients showed a noteworthy downexpression of CDH1 and IFIH1, among others, in docetaxel-resistant tumors. This exploratory analysis provides information about potential gene and network involvement in docetaxel resistance in CRPC. Further clinical validation of these results is needed to develop targeted therapies in patients with CRPC that can circumvent such resistance to treatment. Mol Cancer Ther; 11(2); 329–39. ©2011 AACR.

Nerve fibers accompany blood and lymphatic vessels all over the body. An extensive amount of knowledge has been obtained with regard to tumor angiogenesis and tumor lymphangiogenesis, yet little is known about the potential biological effects of “neoneurogenesis”. Cancer cells can exploit the advantage of the factors released by the nerve fibers to generate a positive microenvironment for cell survival and proliferation. At the same time, they can stimulate the formation of neurites by secreting neurotrophic factors and axon guidance molecules. The neuronal influence on the biology of a neoplasm was initially described several decades ago. Since then, an increasing amount of experimental evidence strongly suggests the existence of reciprocal interactions between cancer cells and nerves in humans. Moreover, researchers have been able to demonstrate a crosstalk between cancer cells and nerve fibers as a strategy for survival. Despite all these evidence, a lot remains to be done in order to clarify the role of neurotransmitters, neuropeptides, and their associated receptor-initiated signaling pathways in the development and progression of cancer, and response to therapy. A global-wide characterization of the neurotransmitters or neuropeptides present in the tumor microenvironment would provide insights into the real biological influences of the neuronal tissue on tumor progression. This review is intended to discuss our current understanding of neurosignaling in cancer and its potential implications on cancer prevention and therapy. The review will focus on the soluble factors released by cancer cells and nerve endings, their biological effects and their potential relevance in the treatment of cancer.

We have previously shown that metalloproteinase 7 (MMP7) expression is increased during the acquisition of resistance to oxaliplatin in colon cancer cells. Now we have analyzed the implication of β-catenin and EGFR pathways in the up-regulation of MMP7 in the oxaliplatin-resistant human colon cancer cell lines RHT29 and RHCT116 p53-/-, derived from the HT29 and HCT116 p53-/- cells, respectively.Oxaliplatin treatment increased EGFR expression and induced its activation in all the cell lines. However, β-catenin mRNA was only upregulated in the HT29 and RHT29 cells, with a marked increase in the nuclear/cytoplasmic β-catenin protein ratio in the oxaliplatin-resistant RHT29 cells. To determine the contribution of β-catenin and EGFR to the expression of MMP7 we performed siRNA experiments. β-catenin abrogation only prevented the induction of MMP7 by oxaliplatin in HT29 and RHT29 cells. Accordingly, viability of oxaliplatin-treated RHT29 cells under β-catenin silencing was decreased. On the other hand, EGFR siRNA induced contradictory effects, decreasing PEA3 and MMP7 expression in control and oxaliplatin-treated RHCT116 p53-/- cells but increasing basal- and oxaliplatin-induced PEA3 and MMP7 in the HT29 and RHT29 cells.Oxaliplatin-induced MMP7 up-regulation is differentially achieved in colon cancer cell lines, as a result of EGFR and β-catenin cross-talk on MMP7 gene transcription. Taken together, our results point out the disparity of effects that β-catenin and EGFR blocking therapeutic strategies may exert on MMP7 expression depending on the cellular context and remark the importance of a better knowledge of MMP7 regulation to improve chemotherapy effectiveness in colon cancer.

Background CD95 is a death receptor controlling not only apoptotic pathways but also activating mechanisms promoting tumor growth. During the acquisition of chemoresistance to oxaliplatin there is a progressive loss of CD95 expression in colon cancer cells and a decreased ability of this receptor to induce cell death. The aim of this study was to characterize some key cellular responses controlled by CD95 signaling in oxaliplatin-resistant colon cancer cells. Results We show that CD95 triggering results in an increased metastatic ability in resistant cells. Moreover, oxaliplatin treatment itself stimulates cell migration and decreases cell adhesion through CD95 activation, since CD95 expression inhibition by siRNA blocks the promigratory effects of oxaliplatin. These promigratory effects are related to the epithelia-to-mesenchymal transition (EMT) phenomenon, as evidenced by the up-regulation of some transcription factors and mesenchymal markers both in vitro and in vivo. Conclusions We conclude that oxaliplatin treatment in cells that have acquired resistance to oxaliplatin-induced apoptosis results in tumor-promoting effects through the activation of CD95 signaling and by inducing EMT, all these events jointly contributing to a metastatic phenotype.

Antithymocyte globulin (ATG) is an effective treatment in patients with severe aplastic anemia (SAA). Its mechanism of action remains unclear, although it has been assumed to be immunosuppressive. However, ATG has also been shown by several laboratories to be immunostimulatory. Recently, interleukin-1 (IL-1) production has been found to be decreased in lipopolysaccharide-stimulated peripheral blood monocytes obtained from SAA patients. We have investigated the ability of ATG to function as an immunostimulatory agent via the production of IL-1 and IL-6 by normal human monocytes in vitro. Supernatants from ATG- stimulated monocytes were assayed for biologically active and immunoreactive IL-1 and IL-6. We have found that ATG, via its F(ab')2 fragment is a powerful inducer of IL-1 and IL-6 production. Furthermore, ATG induction of both cytokines from normal monocytes required de novo synthesis, as determined by 35S-methionine incorporation. Because these two cytokines synergize with other cytokines at both the stem cell and progenitor levels, these stimulatory properties of ATG may be relevant to the treatment of SAA. This would favor the hypothesis of a bimodal mechanism for ATG as an inducer of hematopoietic growth factors and as an immunosuppressive agent.

Background: ABTL0812 is a first-in-class orally administered compound currently in Phase I/Ib First in Human Clinical Trial in patients with advanced solid tumors (NCT02201823). ABTL0812 has cytotoxic effect on a wide range of human tumor cell lines, including those which have become resistant to standard therapy. We hereby dissect the anti-tumor activity of ABTL0812, which relies on a novel mechanism of action that promotes inhibition of the Akt/mTOR axis in cancer cells. Material & methods: ABTL0812 molecular targets were identified by in silico analysis, comparing ABTL0812 chemical structure against a database including more than one million receptor-ligand interaction data. Functional relevance of the targets was confirmed biochemically and pharmacologically. ABTL0812 mechanism of action was established using human lung and pancreatic tumor cells, MEF KO cells, as well as tumor xenografts. Results: In silico screening showed that ABTL0812 binds four targets which regulate tumor progression through Akt/mTOR axis. Two of them are the transcription factors PPARα and PPARγ (Peroxisome-Proliferator Activating Receptors). In lung and pancreatic tumor cells ABTL0812 activated PPARα/γ-dependent gene transcription, while pharmacological inhibition with PPARα/γ antagonists impaired ABTL0812 cytotoxic effect. Interestingly, ABTL0812 induced transcription of the endogenous Akt inhibitor TRIB3 (tribbles homologue 3) through PPARα/γ activation. TRIB3 is a pseudokinase that inhibits Akt by direct binding and preventing its phosphorylation by mTORC2 complex. According to this, ABTL0812-induced TRIB3 overexpression resulted in inhibition of Akt phosphorylation, impaired phosphorylation of the Akt substrates TSC2 and PRAS40 and mTORC1 inhibition (pS6), which in turn promoted autophagy-mediated tumor cell death. MEF TRIB3-/- cells were resistant to ABTL0812-induced cell death, indicating that TRIB3 mediates ABTL0812 citotoxicity. Finally, Akt inhibition was observed in human lung and pancreatic tumor xenograft models treated with ABTL0812 and in human platelets incubated with ABTL0812. This supported the rational for using Akt phosphorylation as a pharmacodynamic biomarker to monitor activity of ABTL0812 in patients included in the Clinical Trial. Conclusion: ABTL0812 promotes autophagy-mediated cell death in different cancer paradigms by inhibiting the Akt/mTOR axis through a novel mechanism of action. ABTL0812 induces PPARα/γ-mediated transcription of the TRIB3 gene. Upregulated TRIB3 protein binds and inhibits Akt, leading to mTORC1 inhibition and reduction of tumor growth. These findings provide evidences that ABTL0812 may be an effective therapeutic strategy for targeting cancer. Citation Format: Tatiana Erazo, Mariana Gomez-Ferreria, Jose Alfon, Mar Lorente, Maria Salazar, Anna Lopez, Marc Cortal, Pau Munoz-Guardiola, Pedro Gascon, Guillermo Velasco, Carles Domenech, Jose M. Lizcano. ABTL0812, a new antitumor drug that inhibits the axis Akt/mTOR through a novel mechanism of action. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 672. doi:10.1158/1538-7445.AM2015-672

Background Substance P (SP) is a pleiotropic cytokine/neuropeptide that enhances breast cancer (BC) aggressiveness by transactivating tyrosine kinase receptors like EGFR and HER2. We previously showed that SP and its cognate receptor NK-1 (SP/NK1-R) signaling modulates the basal phosphorylation of HER2 and EGFR in BC, increasing aggressiveness and drug resistance. In order to elucidate the mechanisms responsible for NK-1R-mediated HER2 and EGFR transactivation, we investigated the involvement of c-Src (a ligand-independent mediator) and of metalloproteinases (ligand-dependent mediators) in HER2/EGFR activation. Results and Discussion Overexpression of NK-1R in MDA-MB-231 and its chemical inhibition in SK-BR-3, BT-474 and MDA-MB-468 BC cells significantly modulated c-Src activation, suggesting that this protein is a mediator of NK-1R signaling. In addition, the c-Src inhibitor 4-(4’-phenoxyanilino)-6,7-dimethoxyquinazoline prevented SP-induced activation of HER2. On the other hand, SP-dependent phosphorylation of HER2 and EGFR decreased substantially in the presence of the MMP inhibitor 1–10, phenanthroline monohydrate, and the dual inhibition of both c-Src and MMP almost abolished the activation of HER2 and EGFR. Moreover, the use of these inhibitors demonstrated that this Src and MMP-dependent signaling is important to the cell viability and migration capacity of HER2+ and EGFR+ cell lines. Conclusion Our results indicate that the transactivation of HER2 and EGFR by the pro-inflammatory cytokine/neuropeptide SP in BC cells is a c-Src and MMP-dependent process.

2585 Background: ABTL0812 is a novel drug with reported preclinical activity in several tumor types. In vitro and in vivo assays have shown that ABTL0812 is an inhibitor of the Akt/mTOR pathway by ...

Pure red cell aplasia (PRCA) is a rare hematological syndrome characterized by the lack of red cell progenitors in an otherwise normocellular bone marrow. Many agents and mechanisms have been implicated in the pathophysiology of PRCA, including immune-mediated dysfunctions. This report describes three patients with PRCA with unknown underlying cause and showed that for each, increases in CD8+ cells blunted the maturation of early erythroid (BFU-E). Each patient subsequently responded to immunosuppressive therapy. Peripheral blood mononuclear cells from age- and sex-matched healthy controls showed comparable distribution of CD3, CD4 and CD16, but significant increase in CD8 and decreased CD19. The distribution of lymphocyte subsets correlated with mitogen responses, but showed no difference in allogeneic responses when compared to controls. The adherent population in PRCA is important for mediating the hyper-immune state of patients, when IL-2 levels were used as readout. There was a trend for decreased BFU-E in patients, but marked reduction for late erythroid progenitors (CFU-E). CD8+ cells from PRCA blunted the maturation of BFU-E, despite increasing erythropoietin concentrations. These results strongly suggest that there are defects in the lymphoid compartment that feedback on the erythroid lineage of PRCA.

Background Malignant lesions derived from mesonephric (Wolffian) remnants are uncommon. The course of these tumors is usually indolent, and the recurrence has only been documented in nine cases. Because of the small number of cases, no current recommendations exist regarding treatment, and little is known about the response to chemotherapeutic agents. Case A 33-year-old woman was diagnosed with a mesonephric adenocarcinoma arising in the uterine corpus. Ten months after initial surgery and radiotherapy she presented with local and pulmonary relapse. Salvage chemotherapy with carboplatin plus paclitaxel was administered with a good response. Conclusions Mesonephric adenocarcinomas are uncommon neoplasms. Their treatment remains elusive. We report a case of a recurrent uterine mesonephric adenocarcinoma that presented a good response to therapy with carboplatin plus paclitaxel. A review of the previous literature is also presented.

Objective The cellular and molecular mechanisms of hematopoietic stimulation have been studied. However, an understanding of negative effects in the hematopoietic system remains elusive. To this end, we studied the effects of vasoactive intestinal peptide (VIP) on bone marrow (BM) progenitors. Materials and Methods Different BM cell subsets were used to perform clonogenic assay for granulocytic (CFU-GM) or erythroid (BFU-E and CFU-E) progenitors with 10 −7 –10 −13 M VIP. The relevant receptor was verified with specific antagonists, or agonists, semi-quantitative RT-PCR, and chemical cross-linking studies with stromal membranes. Results Assays performed with unfractionated mononuclear cells and enriched CD34 + cells showed dose-dependent inhibition on BM progenitors with significant inhibition up to 10 −10 M. Nylon wool separated cells, which depleted stroma, reversed the inhibitory effects of VIP between 10 and 20%. Combined experimental evaluation indicated that the effects of VIP on BM functions are mediated through the type 1 receptor (VPAC1). VIP induced the production of TGF-β and TNF-α in BM mononuclear cells and stroma. These cytokines are partly involved in reversing the suppressive effects of VIP on CFU-GM. Conclusion The effect of VIP on BM progenitors could be mediated through direct and indirect mechanism. Direct effects were evident by the suppressive effects of VIP on clonogenic assays with highly purified CD34 + cells. Indirect effects were mediated through putative functions of the stromal cells and the production of TGF-β and TNF-α.

The neurokinin-1 (NK-1) receptor interacts with peptides that belong to the tachykinin family. NK-1 is inducible in bone marrow (BM) stroma. In neural cells, its expression is high to constitutive. Screening of three cDNA libraries indicated that this different in NK-1 expression in neural and BM cells could not be explained by differences in the cDNA sequence. Analyses the 5' flanking sequence in BM stroma and three neural cell lines indicated that sequence +1/+358 relative to the transcription start (TS) site could account for the differences in NK-1 expression. Particular cytokines could reverse the repressive effects of region +1/+358 in BM stroma. The effects of NF-kappa B and cAMP activators were studied in stromal cells using a dominant negative inhibitor of NF-kappa B (I kappa B) or a repressor of CRE activators (ICERII gamma). The results showed that their effects of these transcription factors depended on the stimulating cytokine. This study provides insight into the tissue-specific differences in the expression of the NK-1 gene.

e16518 Background: Metabolic tumor parameters for preoperative [18F]FDG PET/TC imaging may be a useful predictor of recurrence in patients with epithelial ovarian cancer (EOC). The aim of this stud...

533 Background: Sunitinib is a standard first line treatment of metastatic renal cell carcinoma (ccRCC). Approximately 20% of patients experience primary resistance to therapy and no predictive biomarkers are available. The aim of our study is to discover novel biomarkers to predict response to sunitinib and to generate hypothesis about mechanisms of intrinsic resistance. Methods: Gene expression analysis was performed in formalin-fixed paraffin embedded (FFPE) samples from 44 patients with metastatic ccRCC treated with sunitinib in our institution. Affymetrix Human Gene 2.0 ST array was performed in primary tumors from 6 extremely sensitive (progression free survival (PFS) > 24 months) and 8 refractory (progression disease as best response) ccRCC. Technical validation with qPCR (Fluidigm Dynamic 96.96 Array) was performed in the whole cohort. The ΔΔCt method was used to quantify the relative amount of mRNA. Clinical and pathological data were correlated with gene expression. Results: 330 genes were differentially expressed between refractory and sensitive patients (p≤0.05). Network analysis showed 16 significant networks represented. Gene expression of 96 selected markers was tested in 47 primary tumors and 24 metastases. We found IL8, VEGF and NOTCH pathways upregulated on refractory patients. Survival analysis showed that the overexpression of IL8 correlated with a worse PFS (HR: 2.42, 95%CI1.27 – 4.63, p=0.0075) and overall survival (OS) (HR: 3.42, 95%CI 1.50 – 7.79, p=0.0034). Overexpression of VEGFBcorrelated with a prolonged PFS (HR 0.52, 95% CI 0.28 – 0.98, p=0.0415). Conclusions: Our results confirm the predictive value of IL8 expression in a cohort of ccRCC patients treated with sunitinib and suggests novel biomarkers of response to sunitinib. These data will be further validated in an independent cohort of patients.

Communication within the hematopoietic–neuroendocrine–immune axis is partly mediated by neurotransmitters (e.g. substance P, SP) and cytokines. SP mediates neuromodulation partly through the stimulation of bone marrow (BM) progenitors. This study shows that SP, through the neurokinin-1 receptor, stimulates the proliferation of primitive hematopoietic progenitors: cobblestone-forming cells (CAFC, CD34+). This effect is optimal when macrophage is included within the fibroblast support. Indirect induction of IL-1 could be important in the proliferation of CAFC colonies by SP. Phenotypic and functional studies suggest that SP might directly interact with the CD34+/CD45dim population. These studies indicate that SP can initiate a cascade of biological responses in the BM stroma and stem cells to stimulate hematopoiesis.

Bone marrow (BM) fibrosis may occur in myeloproliferative diseases, lymphoma, myelodysplastic syndrome, myeloma, and infectious diseases. In this study, the role of substance P (SP), a peptide with pleiotropic functions, was examined. Some of its functions—angiogenesis, fibroblast proliferation, and stimulation of BM progenitors—are amenable to inducing BM fibrosis. Indeed, a significant increase was found in SP-immunoreactivity (SP-IR) in the sera of patients with BM fibrosis (n = 44) compared with the sera of patients with hematologic disorders and no histologic evidence of fibrosis (n = 46) (140 ±12 vs 18 ±3; P

We studied the complex interactions within the neuroendocrine-immune-hematopoietic axis by determining a possible link among ACTH, PRL, PPT-I and the receptors for its peptides, NK-1 and NK-2. Indeed, ACTH and PRL induced the expression of PPT-I and NK-1 in human bone marrow stroma with no effect on NK-2. Consistent with a role for PPT-I in regulating the development of myeloid and erythroid progenitors, we found that ACTH and PRL, through NK-1 stimulated the proliferation of both types of progenitors. Induction of PPT-I was regulated at the transcriptional and post-transcriptional levels. The results showed that ACTH and PRL stimulated the proliferation of bone marrow progenitors, partly through PPT-I and NK-1 induction.