Development Of Aggressive Tumors Research Articles

Testis specific gene expression drives disease progression and Rituximab resistance in lymphoma

Testis specific gene expression drives disease progression and Rituximab resistance in lymphoma

Deficiency of Erbin induces resistance of cervical cancer cells to anoikis in a STAT3-dependent manner

Epithelial cell polarization and integration are essential to their function and loss of epithelial polarity and tissue architecture correlates with the development of aggressive tumors. Erbin is a basolateral membrane-associated protein. The roles of Erbin in establishing cell polarization and regulating cell adhesion have been suggested. Erbin is also a negative regulator in Ras-Raf-ERK (extracellular signal-regulated kinase) signaling pathway. However, the potential functions of Erbin in human cancer are basically unknown. In the present study, we show, for the first time, that loss of Erbin endows cervical cancer cells with resistance to anoikis both in vitro and in vivo and promotes the growth and metastasis of human cervical cancer xenografts in nude mice. We found that knockdown of Erbin induced the phosphorylation, nuclear translocation and transcriptional activities of signal transducer and activator of transcription factor 3 (STAT3) in cervical cancer cells. Overexpression of STAT3C or induction of endogenous STAT3 activation by interleukin (IL)-6 evidently inhibited anoikis of cervical cancer cells, whereas WP1066, a potent inhibitor of Janus-activated kinase 2 (Jak2)/STAT3, effectively blocked the effect of Erbin knockdown on cell survival under anchorage-independent conditions, indicating that loss of Erbin confers resistance of cervical cancer cells to anoikis in a STAT3-dependent manner. Interestingly, IL-6 induced STAT3 activation and Erbin expression simultaneously. Overexpression of STAT3C also significantly upregulated the level of Erbin, whereas the Jak2 inhibitor AG490 remarkably blocked not only STAT3 phosphorylation but also IL-6-induced Erbin expression. Knockdown of Erbin augmented the effects of IL-6 on STAT3 activation and anoikis resistance. In addition, by immunohistochemical analysis of Erbin expression, we demonstrate that the expression of Erbin is significantly decreased or even lost in cervical cancer tissues. These data reveal that Erbin is a novel negative regulator of STAT3, and the IL-6/STAT3/Erbin loop has a crucial role in cervical cancer progression and metastasis.

Age dependence of tumor genetics in unfavorable neuroblastoma: arrayCGH profiles of 34 consecutive cases, using a Swedish 25-year neuroblastoma cohort for validation

BackgroundAggressive neuroblastoma remains a significant cause of childhood cancer death despite current intensive multimodal treatment protocols. The purpose of the present work was to characterize the genetic and clinical diversity of such tumors by high resolution arrayCGH profiling.MethodsBased on a 32K BAC whole-genome tiling path array and using 50-250K Affymetrix SNP array platforms for verification, DNA copy number profiles were generated for 34 consecutive high-risk or lethal outcome neuroblastomas. In addition, age and MYCN amplification (MNA) status were retrieved for 112 unfavorable neuroblastomas of the Swedish Childhood Cancer Registry, representing a 25-year neuroblastoma cohort of Sweden, here used for validation of the findings. Statistical tests used were: Fisher’s exact test, Bayes moderated t-test, independent samples t-test, and correlation analysis.ResultsMNA or segmental 11q loss (11q-) was found in 28/34 tumors. With two exceptions, these aberrations were mutually exclusive. Children with MNA tumors were diagnosed at significantly younger ages than those with 11q- tumors (mean: 27.4 vs. 69.5 months; p=0.008; n=14/12), and MNA tumors had significantly fewer segmental chromosomal aberrations (mean: 5.5 vs. 12.0; p<0.001). Furthermore, in the 11q- tumor group a positive correlation was seen between the number of segmental aberrations and the age at diagnosis (Pearson Correlation 0.606; p=0.037). Among nonMNA/non11q- tumors (n=6), one tumor displayed amplicons on 11q and 12q and three others bore evidence of progression from low-risk tumors due to retrospective evidence of disease six years before diagnosis, or due to tumor profiles with high proportions of numerical chromosomal aberrations. An early age at diagnosis of MNA neuroblastomas was verified by registry data, with an average of 29.2 months for 43 cases that were not included in the present study.ConclusionMNA and segmental 11q loss define two major genetic variants of unfavorable neuroblastoma with apparent differences in their pace of tumor evolution and in genomic integrity. Other possible, but less common, routes in the development of aggressive tumors are progression of low-risk infant-type lesions, and gene amplifications other than MYCN. Knowledge on such nosological diversity of aggressive neuroblastoma might influence future strategies for therapy.

MAX and MYC: A Heritable Breakup

The overexpression of MYC, which occurs in many tumors, dramatically disrupts the equilibrium between activation and repression of the oncogenic MYC/MYC-associated protein X (MAX)/MAX dimerization protein 1 (MXD1) network, favoring MYC-MAX complexes and thereby impairing differentiation and promoting cell growth. Although for some time it has appeared that MAX is necessary for both the activation and repression of the axis, recent evidence shows that MYC retains considerable biologic function in the absence of MAX. The presence of germline MAX mutations in patients with hereditary pheochromocytoma supports the predominant role of MAX as a negative regulator of the network and suggests that MYC deregulation plays a role in hereditary cancer predisposition. This finding also confirms the importance of impairment of the MYC/MAX/MXD1 axis in the development of aggressive neural tumors, because MYCN overexpression is an established genetic hallmark of malign neuroblastoma, and it is likely that MXI1 plays a relevant role in the development of medulloblastoma and glioblastoma. Finally, the likely malignant behavior of tumors with mutations in MAX points to MYC as a candidate therapeutic target in the treatment of metastatic pheochromocytoma.

Interleukin‐1β mediates metalloproteinase‐dependent renal cell carcinoma tumor cell invasion through the activation of CCAAT enhancer binding protein β

Effective treatment of metastatic renal cell carcinoma (RCC) remains a major medical concern, as these tumors are refractory to standard therapies and prognosis is poor. Although molecularly targeted therapies have shown some promise in the treatment of this disease, advanced RCC tumors often develop resistance to these drugs. Dissecting the molecular mechanisms underlying the progression to advanced disease is necessary to design alternative and improved treatment strategies. Tumor-associated macrophages (TAMs) found in aggressive RCC tumors produce a variety of inflammatory cytokines, including interleukin-1β (IL-1β). Moreover, the presence of TAMs and high serum levels of IL-1β in RCC patients correlate with advanced disease. We hypothesized that IL-1β in the tumor microenvironment promotes the development of aggressive RCC tumors by directing affecting tumor epithelial cells. To address this, we investigated the role of IL-1β in mediating RCC tumor cell invasion as a measure of tumor progression. We report that IL-1β induced tumor cell invasion of RCC cells through a process that was dependent on the activity of matrix metalloproteinases (MMPs) and was independent of migration rate. Specifically, IL-1β induced the expression of MMP-1, MMP-3, MMP-10, and MT1-MMP in a mechanism dependent on IL-1β activation of the transcription factor CCAAT enhancer binding protein β (CEBPβ). Consistent with its role in MMP gene expression, CEBPβ knockdown significantly reduced invasion, but not migration, of RCC tumor cells. These results identify the IL-1β /CEBPβ/MMP pathway as a putative target in the design of anti-metastatic therapies for the treatment of advanced RCC.

Abstract 3131: Higher IGF-II expression in Vietnamese triple negative breast cancer tumors is dependent on Biallelic or Monoallelic IGF-II with ApaI SNP

Abstract Triple negative breast cancer (TNBC) is more likely to be advanced, poorly differentiated, larger, and present in women of younger age and of lower socioeconomic status. Moreover, TNBC patients have worse outcomes when treated with currently available adjuvant chemotherapy. In the United States, African American (AA) women have a lower incidence of breast cancer compared with Caucasian women (CA), but higher overall mortality. Our lab have demonstrated that BC tumors from AA patients express significantly higher levels of IGF-II and show a higher activation of the IGF signaling pathways (Kalla et.al., 2010a, 2010b). IGF-II levels regulate survival proteins and activate the ER signaling pathway promoting an aggressive tumor development. Thus we designed a study to determine if IGF-II regulates the progression of TNBC tumors. TNBC incidence is increasing in younger Vietnamese women. Thus, we designed a study to analyze the IGF-II expression in paired normal-tumor BC tissues from Vietnamese TNBC patients. Furthermore, we decided to characterize the IGF-II genomic imprinting status, to correlate IGF-II levels with Monoallelic or Biallelic IGF-II gene expression. A total of 24 paired BC samples obtained from ILSbio were analyzed by Western Blot, RT-PCR and gDNA PCR with Apa I restriction digestion. Our results showed that the IGF-II genomic imprinting status in all 24 pairs was the same in normal and tumor tissues from the same patient. The levels of IGF-II correlated with the imprinting status, i.e., Biallelic (BA; n=14)≫, Monoallelic with SNP (MAS; n=5)&amp;gt;, and Monoallelic non-ApaI SNP (MA; n=5)&amp;gt;. Higher IGF-II levels were expressed in tumor as compared to normal tissue from the same patient. The free proIGF-II protein levels were 6.5-15.22 fold higher in biallelic tumor tissues as compared to the proIGF-II levels detected in monoallelic tumor samples. The IGF-II mRNA levels were 0.4-1 fold higher in biallelic tumor tissues as compared to the proIGF-II levels detected in monoallelic tumor samples. We also assessed growth factor receptors; Insulin receptor A (IRA), Insulin receptor B (IRB), Vascular endothelial growth factor receptor (VEGFR), Estrogen receptor-1 (ESR1), Progesterone receptor (PGR) and Human epidermal growth factor receptor (ERBB2) status to determine if IGF-II monoallelic or biallelic dosage regulated the receptor levels. We conclude that biallelic IGF-II expression in TNBC tumors results in higher IGF-II mRNA and protein levels than in monoallelic samples. Furthermore, higher IGF-II resulted in increased expression and signaling activation of IRA, IRB, VEGFR, ESR1, PGR and ERBB2 growth factor receptors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3131. doi:1538-7445.AM2012-3131

1313 MICRORNA EXPRESSION PROFILING OF DIFFERENT GLEASON GRADES IN PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Basic Research II1 Apr 20121313 MICRORNA EXPRESSION PROFILING OF DIFFERENT GLEASON GRADES IN PROSTATE CANCER Naveen Kachroo, Ajay Joseph, Lorenz Wernisch, Anne Warren, Tania Valencia, and Vincent Gnanapragasam Naveen KachrooNaveen Kachroo Cambridge, United Kingdom More articles by this author , Ajay JosephAjay Joseph Cambridge, United Kingdom More articles by this author , Lorenz WernischLorenz Wernisch Cambridge, United Kingdom More articles by this author , Anne WarrenAnne Warren Cambridge, United Kingdom More articles by this author , Tania ValenciaTania Valencia Cambridge, United Kingdom More articles by this author , and Vincent GnanapragasamVincent Gnanapragasam Cambridge, United Kingdom More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.1660AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The Gleason grade is a crucial pathological assessment of the aggressiveness of prostate cancer. The specific mechanisms that result in the evolution of higher Gleason grades however are currently unknown. MicroRNAs are small non-coding RNAs that regulate key cellular biological processes including tumour development. This study investigated if there were distinct microRNAs expressed in prostate tumours of different Gleason grades. METHODS Enriched benign and tumour populations of Gleason grade 3, 4 and 5 foci (pre-marked by a uropathologist) were isolated by laser capture microdissection from formalin fixed paraffin embedded diagnostic prostate needle biopsies of 36 men using a previously published method. MicroRNA expression profiling of the benign (n=9), Gleason 3 (n=9), Gleason 4 (n=9) and Gleason 5 (n=9) samples was performed using the Illumina human miRNA expression array. Bioinformatic analysis was performed with R statistical software, employing strict ranking criteria to profile microRNAs stratified by different tumour grades. RESULTS Hierarchical cluster analysis identified clustering of microRNA expression of benign glands with Gleason 3 tumours and Gleason 4 with Gleason 5 tumours. 39 microRNAs were differentially expressed in the Gleason 4/5 tumours compared to the Gleason 3/benign samples at a p<0.005 significance level. Functional gene target analysis using web based computational algorithms (Targetscan and microrna.org) was then performed for the top 9 altered microRNAs. Upregulated microRNA targets included genes involved in suppressing cell cycle regulation as well as migration and invasion. Conversely, down regulated microRNAs had putative target genes involved in promoting epithelial to mesenchymal transition and invasion. CONCLUSIONS This is the first study to investigate microRNA expression in specific Gleason grades. Our analysis has shown similarities in microRNAs expressed in benign and Gleason 3 foci as opposed to Gleason 4 and 5 foci. A dysregulated 9 microRNA expression panel, discriminatory for high Gleason grades, highlight potential mechanisms driving the development of aggressive high grade prostate tumours. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e532 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Naveen Kachroo Cambridge, United Kingdom More articles by this author Ajay Joseph Cambridge, United Kingdom More articles by this author Lorenz Wernisch Cambridge, United Kingdom More articles by this author Anne Warren Cambridge, United Kingdom More articles by this author Tania Valencia Cambridge, United Kingdom More articles by this author Vincent Gnanapragasam Cambridge, United Kingdom More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

CXCR4 Promotes the Tumorogenicity of Multiple Myeloma, Including Increased Motility, Clonogenicity, up-Regulation of VLA-4, Protection From Chemotherapy and Aggressive Tumor Development In Vivo

Abstract 1801 Background:Multiple myeloma (MM) is by large incurable neoplasm of plasma cells, characterized by accumulation in the bone marrow (BM), in close contact to cellular and extracellular matrix (ECM) components. Chemokine receptor CXCR4 is expressed by the majority of patients' MM cells. It promotes myeloma cell migration and homing to the BM compartment, supports the tumor cells survival and protects the myeloma cells from chemotherapy-induced apoptosis. Further investigation is required to define the specific molecular mechanisms regulated by the CXCR4/CXCL12 axis in MM. However, surface CXCR4 is commonly down-regulated in the MM cell lines. In order to overcome this limitation, the aim of the current study was to produce a reliable model for studying the functional role of high CXCR4 in MM by generating MM cell lines with stable expression of surface CXCR4. Results:To over-express CXCR4, we transduced CXCL12-expressing MM cell lines ARH77 and RPMI8226 with lentiviral vector and generated cell lines with high and stable levels of surface CXCR4. Enhanced CXCR4 expression significantly increased the in vitro survival and growth of the 2 MM cell lines in serum-deprivation conditions (p<0.01). Furthermore, elevated expression of surface CXCR4 prominently increased MM cells motility and promoted CXCL12-dependent transwell migration of the transduced MM cell lines. Highly CXCR4-expressing RPMI8226 and ARH77 cells demonstrated 40% migration in response to CXCL12 (50 ng/ml), versus only 0–5% migration of MM cells with low expression of surface CXCR4 (p<0.01). Furthermore, adhesion of MM cells to either ECM proteins or BMSCs localize the malignant PCs within the BM microenvironment, promote growth and survival of MM cells and play a critical role in myeloma bone disease and tumor invasion. In accordance, we observed induced adhesion of the transfected RPMI8226-CXCR4 cells to ECM components fibronectin and laminin and to BM fibroblasts. Moreover, we found that enhanced CXCR4 not only functionally activates, but rather significantly elevates the surface levels of VLA-4 integrin on the RPMI8226 cells. In addition, we found that CXCR4-expressing MM cells were less sensitive to melphalan- and bortezomib-induced apoptosis, when they were co-cultured with BM fibroblasts. Testing the molecular signaling pathways regulated by CXCR4, we found that elevated CXCR4 increased the basic level of pERK1/2 and pAKT in the MM cells, and promoted their prolonged activation in response to CXCL12 stimulation. Finally, the ability to produce colonies in the soft agar semi-solid culture reflects the tumorigenic capacity of cancer cells and cancer stem cells. Differentiated MM cells thus rarely produce colonies in soft agar. Here, we demonstrate that up regulation of CXCR4 promoted ARH77 and RPMI8226 colony formation, significantly increasing colonies number and size. Lastly, we determined the role of CXCR4 in MM tumor development in vivo. CXCR4-expressing ARH77 and RPMI8226 cells were subcutaneously injected into NOD/SCID mice. CXCR4-expressing cells, but not parental cell lines, produced detectable tumors already 10 days after the injection. Rapid tumor growth was further observed in both CXCR4-expressing cell lines. These findings indicate that CXCR4 provided aggressive phenotype and supported MM growth in vivo. Conclusions:Taken together, our findings clearly demonstrate the important pathophysiologic role of CXCR4 in MM development and progression. Furthermore, for the first time, we provide the evidence for CXCR4 oncogenic potential in MM, showing that CXCR4 promotes the clonogenic growth of MM cells. Our model may further serve to elucidate CXCR4-regulated molecular events potentially involved in the pathogenesis of MM, and strongly support targeting CXCR4 as therapeutic tool in MM. Disclosures:No relevant conflicts of interest to declare.

CXCR4 Antagonist BKT140 Synergizes with Rituximab, Targeting Non Hodgkin Lymphoma (NHL) In Vitro and In Vivo in a Xenograft Model with Bone Marrow Involvement

Abstract 952 Background:B-cell Non Hodgkin lymphoma (NHL) represents the most common malignant lymphoid neoplasm, with heterogeneous pathophysiological and clinical presentation. It may show systemic, nodal or extra nodal localization in various sites, including bone marrow (BM). Although anti-CD20 antibody rituximab significantly improved the outcome of NHL patients, the relapsed/refractory rates are still high. Chemokine receptor CXCR4 and its ligand CXCL12 are critically involved in the survival and trafficking of normal and malignant B lymphocytes. Taking together with the fact that interaction of malignant B cells with stromal cells via CXCR4/CXCL12 signaling may provide chemo-resistance, we hypothesized that blockade of CXCR4 may antagonize the survival and spreading of lymphoma cells and restore their chemo-sensitivity. Results:The effect of CXCR4 antagonist BKT140 on lymphoma cell growth and rituximab-induced cytotoxicity was tested in vitro and in vivo. Inhibition of CXCR4 with BKT140 in CD20-expressing lymphoma cell lines (BL-2, BJAB, Raji, Ramos, SUDHL4, OCI-Ly7) and primary lymphoma cells from patients with BM involvement resulted in significant inhibition of cell growth and in the induction of cell death, respectively. Combination of BKT140 with rituximab significantly enhanced the cytotoxic effect (apoptosis) against the lymphoma cells in a dose-dependent manner (p<0.01). This effect was concurrent with increase in Annexin V binding, loss of ΔΨm and caspase 3 cleavage. These findings indicate that mitochondrial membrane dysfunction and caspase 3 activation are involved in BKT140- and rituximab-mediated lymphoma cell death. Moreover, we were able to show that rituximab induced CXCR4 expression in lymphoma cell lines and primary lymphoma cells, both on mRNA and cell-surface levels, suggesting the possible interaction between CD20 and CXCR4 pathways in NHL. This interaction provides the rationale for CXCR4 targeting in combination with rituximab treatment. Indeed, highly-expressing CXCR4 BL-2 cells were protected by BM stromal cells from rituximab-induced apoptosis, whereas low-CXCR4 BJAB cells were not. The protective effect of stoma was abrogated by BKT140. To evaluate the in vivo anti-lymphoma effect of BKT140 we established a xenograft model of B-cell lymphoma with BM involvement in mice. Human CXCR4-expressing B NHL cell line, BL-2, was subcutaneously implanted into NOD/SCID mice, resulting in the development of aggressive local tumors which specifically spread to the bone marrow. Following the tumor establishment, mice were injected subcutaneously with BKT140, rituximab or with combination of both. BKT140 inhibited the local tumor progression of BL-2 generated tumors. Furthermore, BKT140 treatment significantly reduced the number of BL-2 tumor cells in the BM by 77% (p<0.01) compared to the untreated mice, while rituximab decreased this number only by 20%. Importantly, the combination treatment of BKT140 with rituximab further decreased the number of viable lymphoma cells in the BM, achieving 93% reduction (p<0.012). We found that BKT140 promoted lymphoma cell apoptosis within the bone marrow microenvironment. Furthermore, we found that the number of viable lymphoma cells in the peripheral blood of tumor-bearing animals was also reduced following the treatment with BKT140. Conclusions:Our results demonstrate potent anti-lymphoma effect of CXCR4-specific antagonist BKT140 in vitro and in vivo. The BKT140-mediated anti-lymphoma effect synergizes with that of Rituximab. Moreover, BKT140 effectively targets lymphoma cells in the bone marrow microenvironment, overcoming the stroma-induced resistance to rituximab. These findings suggest the possible interaction between CD20 and CXCR4 pathways in NHL, and provide the scientific basis for the development of novel combined CXCR4-targeted therapies for refractory NHL. Disclosures:No relevant conflicts of interest to declare.

Wnt3 gene expression promotes tumor progression in non-small cell lung cancer

The Wnt gene family encodes the multi-functional signaling glycoproteins regulating various normal and pathological processes including tumorigenesis. We investigated the clinical significance of the Wnt3 gene expression in relation to its target genes, c-Myc and survivin, in patients with non-small cell lung cancer (NSCLC). One hundred and twenty-eight patients who underwent resection of NSCLC were analyzed. Quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate the gene expression of Wnt3, c-Myc, and survivin. Immunohistochemistry was performed to investigate the protein expression of Wnt3, c-Myc, and survivin. The Ki-67 proliferation index and the apoptotic index using the TUNEL method were also evaluated. Twenty-four carcinomas (18.8%) were found to be high-Wnt3 tumors. The high-Wnt3 tumors were significantly more in squamous cell carcinomas than that in adenocarcinomas (P=0.0022). The Wnt3 gene expression was significantly associated with gene expressions of c-Myc (P=0.0103) and survivin (P=0.0009). As a result, the Ki-67 proliferation index was significantly higher in high-Wnt3 tumors than in low-Wnt3 tumors (P=0.0056). The apoptotic index was significantly lower in high-Wnt3 tumors than in low-Wnt3 tumors (P=0.0245). The overall survival rate was significantly lower in patients with high-Wnt3 tumors than in those with low-Wnt3 tumors (P=0.0020). A Cox regression analysis demonstrated that the Wnt3 status was a significant prognostic factor for NSCLC patients (hazard ratio 2.226, P=0.0296). The present study revealed that Wnt3 gene expression was significantly associated with c-Myc and survivin gene expressions, tumor proliferation, and tumor apoptosis. During the progression of NSCLC, Wnt3 overexpression could be associated with the development of more aggressive tumors.

Male pattern baldness and the risk of prostate cancer

BackgroundAndrogens play a role in the development of both androgenic alopecia, commonly known as male pattern baldness, and prostate cancer. We set out to study if early-onset androgenic alopecia was associated with an increased risk of prostate cancer later in life. Patients and methodsA total of 669 subjects (388 with a history of prostate cancer and 281 without) were enrolled in this study. All subjects were asked to score their balding pattern at ages 20, 30 and 40. Statistical comparison was subsequently done between both groups of patients. ResultsOur study revealed that patients with prostate cancer were twice as likely to have androgenic alopecia at age 20 [odds ratio (OR) 2.01, P=0.0285]. The pattern of hair loss was not a predictive factor for the development of cancer. There was no association between early-onset alopecia and an earlier diagnosis of prostate cancer or with the development of more aggressive tumors. ConclusionsThis study shows an association between early-onset androgenic alopecia and the development of prostate cancer. Whether this population can benefit from routine prostate cancer screening or systematic use of 5-alpha reductase inhibitors as primary prevention remains to be determined.

HER2 splice variants and their relevance in breast cancer

&lt;p class="MsoNormal" style="background: white; margin: 0cm 0cm 0pt; text-align: justify;"&gt;&lt;span style="font-size: small;"&gt;&lt;span lang="EN-US"&gt;The HER2 gene amplification occurs in 20-30% of breast cancer and is correlated with a poorer prognosis compared to HER2-negative disease due to increased proliferation and metastatic potential.&lt;span style="color: #231f20;"&gt; Two major types of receptor inhibitors have been developed for therapy and one for each categories is currently used in clinic: i) the humanized monoclonal antibody trastuzumab, directed against the HER2 extracellular domain; and ii) the EGFR/HER2 dual&lt;span style="mso-spacerun: yes;"&gt; &lt;/span&gt;&lt;/span&gt;tyrosine kinase inhibitor lapatinib. &lt;/span&gt;&lt;span lang="EN-US"&gt;However, patients may develop resistance to&lt;/span&gt;&lt;span lang="EN-US"&gt; drugs and show&lt;/span&gt;&lt;span lang="EN-US"&gt; disease progression&lt;/span&gt;&lt;span lang="EN-US"&gt;. Several resistant mechanisms have been explored and are still under investigation. Here, &lt;/span&gt;&lt;span lang="EN-GB"&gt;we focus our attention on the role played by the alternative splicing forms of HER2 in mediating HER2 oncogenic activity and in conditioning the response to HER2 therapies. Three HER2 splice variants have been described so far; the p100 and the herstatin gave raised to two secreted proteins of 100 kd and 68 kd, respectively that act as cell growth inhibitors. Herstatin has been described for its ability to interrupt the constitutive HER2 activation, but also for its capacity to hamper HER2 dimerization with the others HER receptors. Interestingly, herstatin, present as mRNA and protein in non cancerous tissue in areas adjacent to breast carcinoma, is absent as protein in 75% of mammary tumors, &lt;/span&gt;&lt;span lang="EN-US"&gt;which indicates that cancer cells are protected by some intrinsic mechanism against the putative growth-inhibitory effects of this naturally occurring molecule. The third splice form of HER2 gene is the Δ16HER2, encoding for a receptor lacking exon16, whose absence determines a constitutive active dimers with transforming activity in vitro and in vivo. The Δ16HER2 binds to trastuzumab to a less extend, due to conformational changes of the extracellular domain.&lt;span style="mso-spacerun: yes;"&gt; &lt;/span&gt;The Δ16HER2 accounts for almost 9% of the total HER2 transcripts in human breast cancers and, additionally, Δ16HER2 levels are supposed to increase proportionally at the increasing of the HER2 wild-type copy numbers in human primary breast cancers. The availability of a specific assay to determine and quantify the expression levels of this splicing form and the availability of Δ16HER2 transgenic mice models made this variant as the most promising for the development of biodrugs. &lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;span style="font-size: 12pt;" lang="EN-US"&gt;Finally, HER2 carboxy-terminal fragments (CTFs), generated by alternative initiation of translation, were observed in breast cancer patients. In particular, 611-CTF was described to activate multiple signaling pathways since it is expressed as a constitutively active homodimer. Expression of 611-CTF led to development of aggressive and invasive mammary tumors and it was suggested to be a potent oncogene capable of promoting mammary tumor progression and metastasis.&lt;/span&gt;

HER2 splice variants and their relevance in breast cancer

The HER2 gene amplification occurs in 20-30% of breast cancer and is correlated with a poorer prognosis compared to HER2-negative disease due to increased proliferation and metastatic potential. Two major types of receptor inhibitors have been developed for therapy and one for each categories is currently used in clinic: i) the humanized monoclonal antibody trastuzumab, directed against the HER2 extracellular domain; and ii) the EGFR/HER2 dual tyrosine kinase inhibitor lapatinib. However, patients may develop resistance to drugs and show disease progression. Several resistant mechanisms have been explored and are still under investigation. Here, we focus our attention on the role played by the alternative splicing forms of HER2 in mediating HER2 oncogenic activity and in conditioning the response to HER2 therapies. Three HER2 splice variants have been described so far; the p100 and the herstatin gave raised to two secreted proteins of 100 kd and 68 kd, respectively that act as cell growth inhibitors. Herstatin has been described for its ability to interrupt the constitutive HER2 activation, but also for its capacity to hamper HER2 dimerization with the others HER receptors. Interestingly, herstatin, present as mRNA and protein in non cancerous tissue in areas adjacent to breast carcinoma, is absent as protein in 75% of mammary tumors, which indicates that cancer cells are protected by some intrinsic mechanism against the putative growth-inhibitory effects of this naturally occurring molecule. The third splice form of HER2 gene is the Δ16HER2, encoding for a receptor lacking exon16, whose absence determines a constitutive active dimers with transforming activity in vitro and in vivo. The Δ16HER2 binds to trastuzumab to a less extend, due to conformational changes of the extracellular domain. The Δ16HER2 accounts for almost 9% of the total HER2 transcripts in human breast cancers and, additionally, Δ16HER2 levels are supposed to increase proportionally at the increasing of the HER2 wild-type copy numbers in human primary breast cancers. The availability of a specific assay to determine and quantify the expression levels of this splicing form and the availability of Δ16HER2 transgenic mice models made this variant as the most promising for the development of biodrugs. Finally, HER2 carboxy-terminal fragments (CTFs), generated by alternative initiation of translation, were observed in breast cancer patients. In particular, 611-CTF was described to activate multiple signaling pathways since it is expressed as a constitutively active homodimer. Expression of 611-CTF led to development of aggressive and invasive mammary tumors and it was suggested to be a potent oncogene capable of promoting mammary tumor progression and metastasis.

MiR-888: A newly identified miRNA significantly over-expressed in endometrial cancers

Endometrial cancer is the most common gynecological malignancy and the fourth most common cancer in women. With accumulating evidence, microRNAs have emerged as significant players in the development and progression of cancers. The data points to miR-888 playing an important functional role in the development of aggressive endometrial tumors. Future research will focus on identifying and validating the targets of miR-888 to elucidate its mechanism of action and support this hypothesis

Radiation Acts on the Microenvironment to Affect Breast Carcinogenesis by Distinct Mechanisms that Decrease Cancer Latency and Affect Tumor Type

Tissue microenvironment is an important determinant of carcinogenesis. We demonstrate that ionizing radiation, a known carcinogen, affects cancer frequency and characteristics by acting on the microenvironment. Using a mammary chimera model in which an irradiated host is transplanted with oncogenic Trp53 null epithelium, we show accelerated development of aggressive tumors whose molecular signatures were distinct from tumors arising in nonirradiated hosts. Molecular and genetic approaches show that TGFβ mediated tumor acceleration. Tumor molecular signatures implicated TGFβ, and genetically reducing TGFβ abrogated the effect on latency. Surprisingly, tumors from irradiated hosts were predominantly estrogen receptor negative. This effect was TGFβ independent and linked to mammary stem cell activity. Thus, the irradiated microenvironment affects latency and clinically relevant features of cancer through distinct and unexpected mechanisms.

Genetic Predisposition Directs Breast Cancer Phenotype by Dictating Progenitor Cell Fate

Women with inherited mutations in the BRCA1 gene have increased risk of developing breast cancer but also exhibit a predisposition for the development of aggressive basal-like breast tumors. We report here that breast epithelial cells derived from patients harboring deleterious mutations in BRCA1 (BRCA1(mut /+) give rise to tumors with increased basal differentiation relative to cells from BRCA1+/+ patients. Molecular analysis of disease-free breast tissues from BRCA1(mut /+) patients revealed defects in progenitor cell lineage commitment even before cancer incidence. Moreover, we discovered that the transcriptional repressor Slug is an important functional suppressor of human breast progenitor cell lineage commitment and differentiation and that it is aberrantly expressed in BRCA1(mut /+) tissues. Slug expression is necessary for increased basal-like phenotypes prior to and after neoplastic transformation. These findings demonstrate that the genetic background of patient populations, in addition to affecting incidence rates, significantly impacts progenitor cell fate commitment and, therefore, tumor phenotype.

Neuroendocrine differentiation and the ubiquitin-proteasome system in cancer: Partners or enemies?

Neuroendocrine (NE) differentiation of cancer and deregulation of the ubiquitin-proteasome system (UPS) are two processes that have been independently linked to the development of aggressive and treatment-resistant tumors. Striking data suggest a plausible interconnection between these two mechanisms, based on indirect evidence of neuropeptide-induced effects on UPS, reversed by proteasome inhibition and deubiquitinase-like properties of NE markers. Deciphering the model of their exact interactions is one of the keys to targeting the NE malignant phenotype more effectively.

CC3/TIP30 regulates metabolic adaptation of tumor cells to glucose limitation

CC3/TIP30 is a metastasis and tumor suppressor, with reduced or absent expression in a variety of aggressive tumors. Overexpression of CC3 in tumor cells predisposes them to apoptosis in response to different death signals. We found that silencing of CC3 expression does not increase apoptotic resistance of cells. However, it strongly improves survival of tumor cells in response to glucose limitation. HeLa cells with silenced CC3 survive long-term in low glucose, and, in comparison to control HeLa cells, show superior metabolic adaptation to glucose limitation. First, unlike the parental HeLa cells, HeLa with silenced CC3 activate and maintain high levels of mitochondrial respiration that is critical for their ability to thrive in low glucose. Second, silencing of CC3 leads to higher expression levels of mitochondrial proteins in respiration complexes when cells are continuously cultured in limiting glucose. Third, HeLa cells with silenced CC3 maintain higher levels of c-MYC and the M2 isoform of pyruvate kinase in low glucose, contributing to more efficient glycolysis. Fourth, HeLa cells with silenced CC3 fail to fully activate AMPK in response to glucose limitation. Inhibition of AMPK, either pharmacologic or via siRNA, protects control HeLa cells from death in low glucose. The metabolic flexibility acquired by cells after silencing of CC3 could be directly relevant to the development of metastatic and aggressive human tumors that frequently have low or absent expression of CC3.

FMNL2 Enhances Invasion of Colorectal Carcinoma by Inducing Epithelial-Mesenchymal Transition

FMNL2 is a member of diaphanous-related formins that control actin-dependent processes such as cell motility and invasion. Its overexpression in metastatic cell lines and tissues of colorectal carcinoma has been associated with aggressive tumor development in our previous study. But its specific role in cancer is largely unknown. Here we report that FMNL2 is involved in epithelial-mesenchymal transition (EMT) maintenance in human colorectal carcinoma cells. A positive correlation between FMNL2 and vimentin expression and an inverse correlation between FMNL2 and E-cadherin expression were found in colorectal carcinoma cell lines and cancer tissues. Specific knockdown of FMNL2 led to an epithelial-state transition, confirmed by the cobblestone-like phenotype, upregulation of E-cadherin, α-catenin, and γ-catenin, and downregulation of vimentin, snail, slug. Loss of FMNL2 expression lowered the ability of TGF-β to induce cell invasion and EMT, as shown by morphology and the expression levels. Upregulation of vimentin, slug, snail, downregulation of E-cadherin and activation of receptor-Smad3 phosphorylation were observed in M5 and MDCK cells induced by TGF-β, whereas altered expression of these markers was not obvious in FMNL2-depleting M5 cells. High levels of activation of p-MAPK and p-MEK, but not p-PI3K and p-AKT, were observed in SW480/FMNL2+ cells compared with control cells. Treatment with U0126 could abrogate the activation of p-MAPK and p-MEK, whereas LY294002 treatment had no effect on the PI3K/AKT pathway. In conclusion, these findings identify a novel EMT and tumor promoting function for FMNL2, which is involved in TGF-β-induced EMT and colorectal carcinoma cell invasion via Smad3 effectors, or in collaboration with MAPK/MEK pathway.

Enhanced Mammary Progesterone Receptor-A Isoform Activity in the Promotion of Mammary Tumor Progression by Dietary Soy in Rats

Dietary contribution to breast cancer risk, recurrence, and progression remains incompletely understood. Increased consumption of soy and soy isoflavones is associated with reduced mammary cancer susceptibility in women and in rodent models of carcinogenesis. In rats treated with N-methyl-N-nitrosourea, dietary intake of soy protein isolate (SPI) reduced mammary tumor occurrence but increased incidence of more invasive tumors in tumored rats, relative to the control diet casein. Here we evaluated whether mammary tumor progression in tumor-bearing rats lifetime exposed to SPI is associated with deregulated progesterone receptor (PR) isoform expression. In histologically normal mammary glands of rats with invasive ductal carcinoma lesions, PR-A protein levels were higher for SPI- than casein-fed rats, whereas PR-B was undetectable for both groups. Increased mammary PR-A expression was associated with higher transforming growth factor-β1, stanniocalcin-1, and CD44 transcript levels; lower E-cadherin and estrogen receptor-α expression; and reduced apoptotic status in ductal epithelium. Serum progesterone (ng/ml) (CAS: 25.94 ± 3.81; SPI: 13.19 ± 2.32) and estradiol (pg/ml) (CAS: 27.9 ± 4.49; SPI: 68.48 ± 23.87) levels differed with diet. However, sera from rats of both diet groups displayed comparable mammosphere-forming efficiency in human MCF-7 cells. Thus, soy-rich diets may influence the development of more aggressive tumors by enhancing PR-A-dependent signaling in premalignant breast tissues.