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Free access

Yuanyuan Cui, Nagalakshmi Nadiminty, Chengfei Liu, Wei Lou, Chad T Schwartz, and Allen C Gao

Cancer cells reprogram their metabolic pathways to facilitate fast proliferation. Previous studies have shown that overexpression of NF-κB2/p52 (p52) in prostate cancer cells promotes cell growth and leads to castration resistance through aberrant activation of androgen receptor (AR). In addition, these cells become resistant to enzalutamide. In this study, we investigated the effects of p52 activation on glucose metabolism and on response to enzalutamide therapy. Data analysis of gene expression arrays showed that genes including GLUT1 (SLC2A1), PKM2, G6PD, and ME1 involved in the regulation of glucose metabolism were altered in LNCaP cells overexpressing p52 compared with the parental LNCaP cells. We demonstrated an increased amount of glucose flux in the glycolysis pathway, as well as the pentose phosphate pathway (PPP) upon p52 activation. The p52-overexpressing cells increase glucose uptake and are capable of higher ATP and lactate production compared with the parental LNCaP cells. The growth of p52-overexpressing cells depends on glucose in the culture media and is sensitive to glucose deprivation compared with the parental LNCaP cells. Targeting glucose metabolism by the glucose analog 2-deoxy-d-glucose synergistically inhibits cell growth when combined with enzalutamide, and resensitizes p52-overexpressing cells to enzalutamide treatment. These results suggest that p52 modulates glucose metabolism, enhances glucose flux to glycolysis and PPPs, thus facilitating fast proliferation of the cells. Co-targeting glucose metabolism together with AR axis synergistically inhibits cell growth and restores enzalutamide-resistant cells to enzalutamide treatment.

Free access

Sonia Cheng, Wei Liu, Moises Mercado, Shereen Ezzat, and Sylvia L Asa

Thyroid cancer exhibits a spectrum from relatively indolent tumors to tumors that are invasive, metastatic, or progress to poorly differentiated carcinoma. Microarray expression analysis of thyroid cancer cell lines has implicated a member of the melanoma-associated (MAGE) family of cancer–testis antigens in thyroid cancer development and progression. We performed this study to validate the role of MAGE in human thyroid cancers. A tissue microarray (TMA) of samples from 375 patients with thyroid cancer was analyzed with immunohistochemistry (IHC) to localize MAGE. Western blotting of fractionated proteins from MAGE-transfected cells was used to confirm intracellular localization of proteins. Automated analysis of TMA samples was evaluated and subjected to statistical analysis. MAGE immunoreactivity was identified in nuclear and cytoplasmic compartments of normal and malignant tissues. Specificity of staining was proved by fractionation studies that confirmed MAGE expression in nucleus and cytoplasm. Normal thyroid tissue exhibited weak cytoplasmic and strong nuclear MAGE reactivity. Tumors exhibited an increase in cytoplasmic MAGE scores that correlated with clinical behavior: larger tumors had higher MAGE scores, and there was a positive and significant correlation between MAGE cytoplasmic score and the number of histologically proven lymph node metastases. There was a statistically significant negative correlation between cytoplasmic MAGE and the percentage of p53-positive nuclei. Our data confirm gene-profiling evidence that members of the MAGE family play a role in thyroid cancer progression. The use of TMA analyses identifies IHC techniques that are translatable to the clinical setting for prognostic assessment of patients with thyroid cancer.

Free access

Yu-fang Bi, Rui-xin Liu, Lei Ye, Hai Fang, Xiao-ying Li, Wei-qing Wang, Ji Zhang, Kan-Kan Wang, Lei Jiang, Ting-wei Su, Zhong-yuan Chen, and Guang Ning

Although there has been increased knowledge about the molecular biology of neuroendocrine tumors (NETs), little is known about thymic carcinoids and even less about those with excessive hormone disorders, such as ectopic ACTH syndrome. This study was designed to gain insights into the molecular networks underlying the tumorigenesis of thymic carcinoids with ACTH secretion. By an approach integrating cDNA microarray and methods of computational biology, we compare gene expression profile between ACTH-producing thymic carcinoids and the normal thymus. In total, there are 63 biological categories increased and 108 decreased in thymic carcinoids. Cell proliferation was stimulated, which may explain the relatively uncontrolled cell growth of the tumor. Dysregulation of the Notch-signaling pathway was likely to be underlying the neuroendocrine features of this type of tumors. Moreover, inhibition of immunity and increased neuropeptide signaling molecules (POMC and its sorting molecule CPE) made the clinical manifestation reasonable and thus validated the array data. In conclusion, thymic carcinoids have a distinct gene expression pattern from the normal thymus, and they are characterized by deregulations of a series of biofunctions, which may be involved in the development of NETs. Hence, this study has provided not only a detailed comprehension of the molecular pathogenesis of thymic carcinoids with ectopic ACTH syndrome, but also a road map to approach thymic NETs at the system level.

Free access

Wu Guojun, Guo Wei, Ouyan Kedong, He Yi, Xie Yanfei, Chen Qingmei, Zhang Yankai, Wu Jie, Fan Hao, Li Taiming, Liu Jingjing, and Cao Rongyue

Gastrin-releasing peptide (GRP), a bombesin-like peptide, is an autocrine growth factor that can stimulate the growth of various cancer cells. We developed a novel protein vaccine HSP65-(GRP-10)6 (HG6) that consists of six copies of a 10-amino acid residue epitope of GRP C-terminal fragment carried by mycobacterial 65 kDa HSP65 and then immunized mice via subcutaneous injection. Strong humoral and cell-mediated immune responses were induced. High titer of anti-GRP antibodies was detected in immunized mice sera by ELISA and verified by Western blot analysis. Activity of CD4+T lymphocytes, especially high levels of interferon (INF)-γ, were developed in mice immunized with HG6 when compared with HSP65 or PBS. We found that immunogene tumor therapy with a vaccine based on GRP was effective at both protective and therapeutic antitumor immunity in breast tumor models in mice. The purified GRP monoclonal antibody (McAb) was proved to be potential in inhibiting EMT-6 tumor cell proliferation in vitro. The attenuation induced by active immune responses on tumor-induced angiogenesis was observed with an intradermal tumor model in mice. Taken together, we demonstrate for the first time that immune responses that are elicited by a novel chimeric protein vaccine targeting GRP can suppress the proliferation of breast tumor cell EMT-6 in mice, and it may be of importance in the further exploration of the applications of other autocrine growth factor identified in human and other animal in cancer therapy.

Free access

Xiao-hui Luo, Jian-zhou Liu, Bo Wang, Qun-li Men, Yu-quan Ju, Feng-yan Yin, Chao Zheng, and Wei Li

Insights into the mechanisms by which key factors stimulate cell growth under androgen-depleted conditions is a premise to the development of effective treatments with clinically significant activity in patients with castration-resistant prostate cancer (CRPC). Herein, we report that, the expression of Krüppel-like factor 14 (KLF14), a master transcription factor in the regulation of lipid metabolism, was significantly induced in castration-insensitive PCa cells and tumor tissues from a mouse xenograft model of CRPC. KLF14 upregulation in PCa cells, which was stimulated upstream by oxidative stress, was dependent on multiple pathways including PI3K/AKT, p42/p44 MAPK, AMPK and PKC pathways. By means of ectopic overexpression and genetic inactivation, we further show that KLF14 promoted cell growth via positive regulation of the antioxidant response under androgen-depleted conditions. Mechanistically, KLF14 coupled to p300 and CBP to enhance the transcriptional activation of HMOX1, the gene encoding the antioxidative enzyme heme oxygenase-1 (HO-1) that is one of the most important mechanisms of cell adaptation to stress. Transient knockdown of HMOX1 is sufficient to overcome KLF14 overexpression-potentiated PCa cell growth under androgen-depleted conditions. From a pharmacological standpoint, in vivo administration of ZnPPIX (a specific inhibitor of HO-1) effectively attenuates castration-resistant progression in the mouse xenograft model, without changing KLF14 level. Together, these results provide comprehensive insight into the KLF14-dependent regulation of antioxidant response and subsequent pathogenesis of castration resistance and indicate that interventions targeting the KLF14/HO-1 adaptive mechanism should be further explored for CRPC treatment.

Open access

Jing Nie, Guang-long Huang, Sheng-Ze Deng, Yun Bao, Ya-Wei Liu, Zhan-Peng Feng, Chao-Hu Wang, Ming Chen, Song-Tao Qi, and Jun Pan

Craniopharyngiomas (CPs) are usually benign, non-metastasizing embryonic malformations originating from the sellar area. They are, however, locally invasive and generate adherent interfaces with the surrounding brain parenchyma. Previous studies have shown the tumor microenvironment is characterized by a local abundance of adenosine triphosphate (ATP), infiltration of leukocytes and elevated levels of pro-inflammatory cytokines that are thought to be responsible, at least in part, for the local invasion. Here, we examine whether ATP, via the P2X7R, participates in the regulation of cytokine expression in CPs. The expression of P2X7R and pro-inflammatory cytokines were measured at the RNA and protein levels both in tumor samples and in primary cultured tumor cells. Furthermore, cytokine modulation was measured after manipulating P2X7R in cultured tumor cells by siRNA-mediated knockdown, as well as pharmacologically by using selective agonists and antagonists. The following results were observed. A number of cytokines, in particular IL-6, IL-8 and MCP-1, were elevated in patient plasma, tumor tissue and cultured tumor cells. P2X7R was expressed in tumor tissue as well as in cultured tumor cells. RNA expression as measured in 48 resected tumors was positively correlated with the RNA levels of IL-6, IL-8 and MCP-1 in tumors. Furthermore, knockdown of P2X7R in primary tumor cultures reduced, and stimulation of P2XR7 by a specific agonist enhanced the expression of these cytokines. This latter stimulation involved a Ca2+-dependent mechanism and could be counteracted by the addition of an antagonist. In conclusion, the results suggest that P2X7R may promote IL-6, IL-8 and MCP-1 production and secretion and contribute to the invasion and adhesion of CPs to the surrounding tissue.

Free access

Zhi-yuan Pang, Yun-tao Wei, Mu-yan Shang, Shuang Li, Yang Li, Quan-xiu Jin, Zhi-xuan Liao, Ming-ke Cui, Xiao-yan Liu, and Qiang Zhang

Aberrant leptin signaling and overexpression of fibroblast growth factor receptor 1 (FGFR1) are both implicated in the pathogenesis of letrozole resistance in breast cancer (BCa), but it remains unknown whether these two pathways are involved in letrozole resistance in a coordinated manner. Here, we demonstrate that expression levels of the pre-B-cell leukemia homeobox transcription factor 3 (PBX3), a pioneer factor that governs divergent biological processes, were significantly upregulated in letrozole-resistant BCa cells and tissues, and this upregulation correlated to a poorer progression-free survival in patients. By leveraging a patient-derived xenograft model with pharmacological approaches, we demonstrated that leptin activated PBX3 expression in a STAT3 (signal transducer and activator of transcription 3)-dependent manner. Our loss- and gain-of-function study further showed that PBX3 attenuated response to letrozole by potentiating BCa cell survival and anchorage-independent growth in BCa cells. By profiling BCa cells with ectopic PBX3 expression, we revealed that PBX3 conferred letrozole resistance via transactivation of the FGFR1 signaling, and this molecular event must coordinate a synergistic transcription activation programs through interacting with MTA1-HDAC2 (metastasis-associated 1-histone deacetylase 2) complex. Overall, the available data reveal a novel role of leptin/PBX3 cascade linking energy homeostasis (i.e. hyperleptinemia) and endocrine therapy failure (i.e. letrozole resistance) in BCa.

Free access

Xiao-Hua Jiang, Jie-Li Lu, Bin Cui, Yong-Ju Zhao, Wei-qing Wang, Jian-Min Liu, Wen-Qiang Fang, Ya-Nan Cao, Yan Ge, Chang-xian Zhang, Huguette Casse, Xiao-Ying Li, and Guang Ning

Multiple endocrine neoplasia type 1 (MEN1) is an inherited tumour syndrome characterized by the development of tumours of the parathyroid, anterior pituitary and pancreatic islets, etc. Heterozygous germ line mutations of MEN1 gene are responsible for the onset of MEN1. We investigated the probands and 31 family members from eight unrelated Chinese families associated with MEN1 and identified four novel mutations, namely 373_374ins18, 822delT, 259delT and 1092delC, as well as three previously reported mutations, such as 357_360delCTGT, 427_428delTA and R108X (CGA>TGA) of MEN1 gene. Furthermore, we detected a loss of heterozygosity (LOH) at chromosome 11q in the removed tumours, including gastrinoma, insulinoma and parathyroid adenoma from two probands of MEN1 families. RT-PCR and direct sequencing showed that mutant MEN1 transcripts remained in the MEN1-associated endocrine tumours, whereas normal menin proteins could not be detected in those tumours by either immunohistochemistry or immunoblotting. In conclusion, MEN1 heterozygous mutations are associated with LOH and menin absence, which are present in MEN1-associated endocrine tumours.

Free access

Yangang Wang, Meiju Ji, Wei Wang, Zhimin Miao, Peng Hou, Xinyan Chen, Feng Xu, Guangwu Zhu, Xianlu Sun, Yujun Li, Steven Condouris, Dingxie Liu, Shengli Yan, Jie Pan, and Mingzhao Xing

The relationship among BRAF mutation, platelet counts, and platelet-derived growth factor (PDGF) with respect to clinicopathological outcomes of papillary thyroid cancer (PTC) may play a role in PTC pathogenesis but remains undefined. We examined the T1799A BRAF mutation by direct genomic DNA sequencing in 108 primary PTC samples from a Chinese cohort and analyzed its relationship with clinicopathological, hematological, and other laboratory results as well as the levels of expression of PDGF in tumors. We found that the BRAF mutation was significantly associated with extrathyroidal invasion and advanced tumor stages III and IV. Specifically, extrathyroidal invasion was seen in 30/54 (56%) PTC with BRAF mutation versus 18/54 (33%) PTC without the mutation (P=0.02). Tumor stages III and IV were seen in 16/54 (30%) PTC with BRAF mutation versus 7/54 (13%) PTC without the mutation (P=0.04). The BRAF mutation was also significantly associated with a higher platelet count, with 249.28±53.76×109/l in the group of patients with BRAF mutation versus 207.79±58.98×109/l in the group without the mutation (P=0.001). An association of higher platelet accounts with extrathyroidal invasion was also seen, with 242.66±51.85×109/l in patients with extrathyroidal invasion versus 218.49±59.10×109/l in patients without extrathyroidal invasion (P=0.03). The BRAF T1799A-positive PTC tissues harbored a significantly higher level of PDGF-B than BRAF T1799A-negative PTC tissues. The data suggest that the BRAF T1799A mutation is associated with aggressive pathological outcomes of PTC in which high platelet counts and increased PDGF production may play a role.

Free access

Bo Chen, Guochun Zhang, Guangnan Wei, Yulei Wang, Liping Guo, Jiali Lin, Kai Li, Hsiaopei Mok, Li Cao, Chongyang Ren, Lingzhu Wen, Minghan Jia, Cheukfai Li, Ting Hou, Han Han-Zhang, Jing Liu, Charles M Balch, and Ning Liao

HER2-positive breast cancer is a biologically and clinically heterogeneous disease. Based on the expression of hormone receptors (HR), breast tumors can be further categorized into HR positive and HR negative. Here, we elucidated the comprehensive somatic mutation profile of HR+ and HR− HER2-positive breast tumors to understand their molecular heterogeneity. In this study, 64 HR+/HER2+ and 43 HR-/HER2+ stage I-III breast cancer patients were included. Capture-based targeted sequencing was performed using a panel consisting of 520 cancer-related genes, spanning 1.64 megabases of the human genome. A total of 1119 mutations were detected among the 107 HER2-positive patients. TP53, CDK12 and PIK3CA were the most frequently mutated, with mutation rates of 76, 61 and 49, respectively. HR+/HER2+ tumors had more gene amplification, splice site and frameshift mutations and a smaller number of missense, nonsense and insertion-deletion mutations than HR-/HER2+ tumors. In KEGG analysis, HR+/HER2+ tumors had more mutations in genes involved in homologous recombination (P = 0.004), TGF-beta (P = 0.007) and WNT (P = 0.002) signaling pathways than HR-/HER2+ tumors. Moreover, comparative analysis of our cohort with datasets from The Cancer Genome Atlas and Molecular Taxonomy of Breast Cancer International Consortium revealed the distinct somatic mutation profile of Chinese HER2-positive breast cancer patients. Our study revealed the heterogeneity of somatic mutations between HR+/HER2+ and HR-/HER2+ in Chinese breast cancer patients. The distinct mutation profile and related pathways are potentially relevant in the development of optimal treatment strategies for this subset of patients.