Expression analysis of genes at 3q26-q27 involved in frequent amplification in squamous cell lung carcinoma

Effects of organophosphates on precision-cut kidney slices

Organophosphate (OP) poisoning, both accidental and with suicidal intent, is a global medical challenge. While the primary toxicity of these pesticides is based on the inhibition of acetylcholinesterase (AChE), case reports describe patients developing OP-mediated renal insufficiency. We set out to investigate possible pathomechanisms utilizing rat precision-cut kidney slices (PCKS). Depending on the method of investigation, PCKS were observed for a maximum of 10 days. PCKS exposed to OP compounds (malaoxon, malathion, paraoxon, parathion) showed a dose-dependent loss of viability and a reduction of total protein content over the course of 10 days. A concentration of 500 µM OP showed the most differences between OP compounds. After two days of incubation parathion showed a significantly lower level of viability than malathion. The respective effects of paraoxon and malaoxon were not significantly different from the control. However, effects of OP were only observed in concentrations exceeding those that were needed to achieve significant AChE inhibition in rat kidney tissue. In addition, we observed histological changes, without inducing LDH leakage. Overall, results suggest that OP exert effects in kidney tissue, that exceed those expected from the sole inhibition of AChE and vary between compounds. Without signs of necrosis, findings call for studies that address other possible pathomechanisms, including inflammatory response, oxidative stress or activation of apoptosis to further understand the nephrotoxicity of OP compounds. Monitoring oxon concentration over time, we demonstrated reduced enzyme-inhibiting properties in the presence of PCKS, suggesting interactions between OP compound and kidney tissue.

Efficacy of radiation exposure in laryngeal squamous cell carcinoma is mediated by the LAMP3/LAMC2/tenascin-C pathway

The present study explored the role of LAMP3 and related molecular mechanisms in the efficacy of radiation exposure in laryngeal squamous cell carcinoma (LSCC). A lentivirus vector containing the LAMP3 gene was transfected into HEp-2 cells to construct siRNA-LAMP3 and complementation (siLAMP3+LAMP3) groups. Treatment with 4 Gy or 8 Gy radiation was administered to evaluate the role of LAMP3 in radiation therapy. Apoptosis was detected by Annexin V/propidium iodide double staining. Cell migration and invasion were measured in vitro using Transwell and Matrigel assays. Downstream genes regulated by LAMP3 were analyzed using RNA sequencing. Furthermore, a patient-derived xenograft (PDX) model of LSCC was established to verify the efficacy of radiation exposure and the associated signaling pathways downstream of LAMP3. The efficacy of radiation showed that cell proliferation was significantly inhibited by siRNA-LAMP3 knockdown. Increased apoptosis was also observed. Notably, the inhibitory effect was attenuated and apoptosis rates were decreased after LAMP3 complementation. In vitro cellular assays showed that migration and invasion were significantly suppressed by siRNA-LAMP3 knockdown and increased after LAMP3 complementation. Analysis of the efficacy of radiation exposure in the PDX model showed that LAMP3-specific knockdown inhibited tumor growth and that tumor growth was further reduced by the combined radiotherapy treatment. According to transcriptome analysis, the extracellular matrix-receptor interaction pathway is regulated by LAMP3, and further analysis revealed significant differences in key-associated molecules, including laminin subunit gamma-2 (LAMC2) and tenascin-C (TNC). Validation of the in vivo PDX model using qPCR and Western blot analyses supported the abovementioned results. The present findings suggest that reduced LAMP3 expression enhances the efficacy of radiation exposure in LSCC by regulating the LAMP3/LAMC2/TNC signaling pathway.

The Dual Roles of the Atypical Protein Kinase Cs in Cancer

Atypical protein kinase C (aPKC) isozymes, PKCλ/ι and PKCζ, are now considered fundamental regulators of tumorigenesis. However, the specific separation of functions that determine their different roles in cancer is still being unraveled. Both aPKCs have pleiotropic context-dependent functions that can translate into tumor-promoter or -suppressive functions. Here, we review early and more recent literature to discuss how the different tumor types, and their microenvironments, might account for the selective signaling of each aPKC isotype. This is of clinical relevance because a better understanding of the roles of these kinases is essential for the design of new anti-cancer treatments.

LAMPs: Shedding light on cancer biology

Lysosomes are important cytoplasmic organelles whose critical functions in cells are increasingly being understood. In particular, despite the long-standing accepted concept about the role of lysosomes as cellular machineries solely assigned to degradation, it has been demonstrated that they play active roles in homeostasis and even in cancer biology. Indeed, it is now well documented that during the process of cellular transformation and cancer progression lysosomes are changing localization, composition, and volume and, through the release of their enzymes, lysosomes can also enhance cancer aggressiveness. LAMPs (lysosome associated membrane proteins) represent a family of glycosylated proteins present predominantly on the membrane of lysosomes whose expression can vary among different tissues, suggesting a separation of functions. In this review we focus on the functions and roles of the different LAMP family members, with a particular emphasis on cancer progression and metastatic spread. LAMP proteins are involved in many different aspects of cell biology and can influence cellular processes such as phagocytosis, autophagy, lipid transport, and aging. Interestingly, for all the five members identified so far (LAMP1, LAMP2, LAMP3, CD68/Macrosialin/LAMP4, and BAD-LAMP/LAMP5), a role in cancer has been suggested. While this is well documented for LAMP1 and LAMP2, the involvement of the other three proteins in cancer progression and aggressiveness has recently been proposed and remains to be elucidated. Here we present different examples about how LAMP proteins can influence and support tumor growth and metastatic spread, emphasizing the impact of each single member of the family.

Metabolic Reprogramming by the PI3K-Akt-mTOR Pathway in Cancer

In the past decade, there has been a resurgence of interest in elucidating how metabolism is altered in cancer cells and how such dependencies can be targeted for therapeutic gain. At the core of this research is the concept that metabolic pathways are reprogrammed in cancer cells to divert nutrients toward anabolic processes to facilitate enhanced growth and proliferation. Importantly, physiological cellular signaling mechanisms normally tightly regulate the ability of cells to gain access to and utilize nutrients, posing a fundamental barrier to transformation. This barrier is often overcome by aberrations in cellular signaling that drive tumor pathogenesis by enabling cancer cells to make critical cellular decisions in a cell-autonomous manner. One of the most frequently altered pathways in human cancer is the PI3K-Akt-mTOR signaling pathway. Here, we describe mechanisms by which this signaling network is responsible for controlling cellular metabolism. Through both the post-translational regulation and the induction of transcriptional programs, the PI3K-Akt-mTOR pathway coordinates the uptake and utilization of multiple nutrients, including glucose, glutamine, nucleotides, and lipids, in a manner best suited for supporting the enhanced growth and proliferation of cancer cells. These regulatory mechanisms illustrate how metabolic changes in cancer are closely intertwined with oncogenic signaling pathways that drive tumor initiation and progression.

Chromosomal and Genetic Analysis of a Human Lung Adenocarcinoma Cell Line OM

Background:

Lung cancer has become the leading cause of death in many regions. Carcinogenesis is caused by the stepwise accumulation of genetic and chromosomal changes. The aim of this study was to investigate the chromosome and gene alterations in the human lung adenocarcinoma cell line OM.

Methods:

We used Giemsa banding and multiplex fluorescence in situ hybridization focusing on the human lung adenocarcinoma cell line OM to analyze its chromosome alterations. In addition, the gains and losses in the specific chromosome regions were identified by comparative genomic hybridization (CGH) and the amplifications of cancer-related genes were also detected by polymerase chain reaction (PCR).

Results:

We identified a large number of chromosomal numerical alterations on all chromosomes except chromosome X and 19. Chromosome 10 is the most frequently involved in translocations with six different interchromosomal translocations. CGH revealed the gains on chromosome regions of 3q25.3-28, 5p13, 12q22-23.24, and the losses on 3p25-26, 6p25, 6q26-27, 7q34-36, 8p22-23, 9p21-24, 10q25-26.3, 12p13.31-13.33 and 17p13.1-13.3. And PCR showed the amplification of genes: Membrane metalloendopeptidase (MME), sucrase-isomaltase (SI), butyrylcholinesterase (BCHE), and kininogen (KNG).

Conclusions:

The lung adenocarcinoma cell line OM exhibited multiple complex karyotypes, and chromosome 10 was frequently involved in chromosomal translocation, which may play key roles in tumorigenesis. We speculated that the oncogenes may be located at 3q25.3-28, 5p13, 12q22-23.24, while tumor suppressor genes may exist in 3p25-26, 6p25, 6q26-27, 7q34-36, 8p22-23, 9p21-24, 10q25-26.3, 12p13.31-13.33, and 17p13.1-13.3. Moreover, at least four genes (MME, SI, BCHE, and KNG) may be involved in the human lung adenocarcinoma cell line OM.

High Expression of LAMP3 Is a Novel Biomarker of Poor Prognosis in Patients with Esophageal Squamous Cell Carcinoma

Lysosomal-associated membrane protein 3 (LAMP3), identified as a molecular marker of mature dendritic cells, is one of the LAMP family members. Its expression was induced by hypoxia, and was associated with hypoxia mediated metastasis in breast and cervical cancers. However, epithelial expression of LAMP3 and its prognostic value in esophageal squamous cell carcinoma (ESCC) is still unknown. In the current study, mRNA expression of LAMP3 in 157 ESCC tissues and 50 adjacent normal tissues was detected by quantitative real-time PCR (qRT-PCR). LAMP3 protein expression in 46 paired cancerous and normal tissues was detected by immunohistochemistry (IHC). Then, DNA copy number was examined to observe its potential correlation with mRNA expression. The results showed that both mRNA and protein expression level of LAMP3 was significantly higher in cancerous tissues compared with normal controls (p < 0.001). LAMP3 DNA copy number was amplified in 70% of ESCC tissues and positive correlated with mRNA expression (p = 0.037). Furthermore, patients with higher LAMP3 expression had worse overall survival (HR = 1.90, 95% CI = 1.17-3.09, p = 0.010) and disease-free survival (HR = 1.80, 95% CI = 1.18-2.74, p = 0.006). In conclusion, our results suggest that epithelial LAMP3 expression is an independent prognostic biomarker for ESCC.

ECT2 amplification and overexpression as a new prognostic biomarker for early-stage lung adenocarcinoma

Genetic abnormality in early-stage lung adenocarcinoma was examined to search for new prognostic biomarkers. Six in situ lung adenocarcinomas and nine small but invasive adenocarcinomas were examined by array-comparative genomic hybridization, and candidate genes of interest were screened. To examine gene abnormalities, 83 cases of various types of lung carcinoma were examined by quantitative real-time genomic PCR and immunohistochemistry. The results were then verified using another set of early-stage adenocarcinomas. Array-comparative genomic hybridization indicated frequent amplification at chromosome 3q26. Of the seven genes located in this region, we focused on the epithelial cell transforming sequence 2 (ECT2) oncogene, as ECT2 amplification was detected only in invasive adenocarcinoma, and not in in situ carcinoma. Quantitative PCR and immunohistochemistry analyses also detected overexpression of ECT2 in invasive adenocarcinoma, and this was correlated with both the Ki-67 labeling index and mitotic index. In addition, it was associated with disease-free survival and overall survival of patients with lung adenocarcinoma. These results were verified using another set of early-stage adenocarcinomas resected at another hospital. Abnormality of the ECT2 gene occurs at a relatively early stage of lung adenocarcinogenesis and would be applicable as a new biomarker for prognostication of patients with lung adenocarcinoma.

Integrative genomics analysis identifies candidate drivers at 3q26-29 amplicon in squamous cell carcinoma of the lung

PURPOSE

Chromosome 3q26-29 is a critical region of genomic amplification in lung squamous cell carcinomas (SCC). Identification of candidate drivers in this region could help uncover new mechanisms in the pathogenesis and potentially new targets in SCC of the lung.

EXPERIMENTAL DESIGN

We conducted a meta-analysis of seven independent datasets containing a total of 593 human primary SCC samples to identify consensus candidate drivers in 3q26-29 amplicon. Through integrating protein-protein interaction network information, we further filtered for candidates that may function together in a network. Computationally predicted candidates were validated using RNA interference (RNAi) knockdown and cell viability assays. Clinical relevance of the experimentally supported drivers was evaluated in an independent cohort of 52 lung SCC patients using survival analysis.

RESULTS

The meta-analysis identified 20 consensus candidates, among which four (SENP2, DCUN1D1, DVL3, and UBXN7) are involved in a small protein-protein interaction network. Knocking down any of the four proteins led to cell growth inhibition of the 3q26-29-amplified SCC. Moreover, knocking down of SENP2 resulted in the most significant cell growth inhibition and downregulation of DCUN1D1 and DVL3. Importantly, a gene expression signature composed of SENP2, DCUN1D1, and DVL3 stratified patients into subgroups with different response to adjuvant chemotherapy.

CONCLUSION

Together, our findings show that SENP2, DCUN1D1, and DVL3 are candidate driver genes in the 3q26-29 amplicon of SCC, providing novel insights into the molecular mechanisms of disease progression and may have significant implication in the management of SCC of the lung.

True 3q chromosomal amplification in squamous cell lung carcinoma by FISH and aCGH molecular analysis: impact on targeted drugs

Squamous lung carcinoma lacks specific "ad hoc" therapies. Amplification of chromosome 3q is the most common genomic aberration and this region harbours genes having role as novel targets for therapeutics. There is no standard definition on how to score and report 3q amplification. False versus true 3q chromosomal amplification in squamous cell lung carcinoma may have tremendous impact on trials involving drugs which target DNA zones mapping on 3q. Forty squamous lung carcinomas were analyzed by FISH to assess chromosome 3q amplification. aCGH was performed as gold-standard to avoid false positive amplifications. Three clustered patterns of fluorescent signals were observed. Eight cases out of 40 (20%) showed ≥8 3q signals. Twenty out of 40 (50%) showed from 3 to 7 signals. The remaining showed two fluorescent signals (30%). When corrected by whole chromosome 3 signals, only cases with ≥8 signals maintained a LSI 3q/CEP3 ratio >2. Only the cases showing 3q amplification by aCGH (+3q25.3-3q27.3) showed ≥8 fluorescent signals at FISH evidencing a 3q/3 ratio >2. The remaining cases showed flat genomic portrait at aCGH on chromosome 3. We concluded that: 1) absolute copy number of 3q chromosomal region may harbour false positive interpretation of 3q amplification in squamous cell carcinoma; 2) a case results truly "amplified for chromosome 3q" when showing ≥8 fluorescent 3q signals; 3) trials involving drugs targeting loci on chromosome 3q in squamous lung carcinoma therapy have to consider false versus true 3q chromosomal amplification.

Targeting the PI3K pathway for cancer therapy

The PI3K pathway plays an important role in key cellular functions such as cell growth, proliferation and survival. Genetic and epigenetic alterations in different pathway components lead to aberrant pathway activation and have been observed in high frequencies in various tumor types. Consequently, significant effort has been made to develop antineoplastic agents targeting different nodes in this pathway. Additionally, PI3K pathway status may have predictive and prognostic implications, and may contribute to drug resistance in tumor cells. This article provides an overview of our current knowledge of the PI3K pathway with an emphasis on its application in cancer treatment.

Butyrylcholinesterase genotype and gender influence Alzheimer's disease phenotype

Retrospective data are presented to support a spectrum of early Alzheimer's disease (AD) along a continuum defined by gender and genotype. The putative neurodegenerative mechanisms driving distinct phenotypes at each end of the spectrum are glial hypoactivity associated with early failure of synaptic cholinergic neurotransmission and glial overactivation associated with loss of neural network connectivity due to accelerated age-related breakdown of myelin. In early AD, male butyrylcholinesterase K-variant carriers with one or two apolipoprotein ɛ4 alleles have prominent medial temporal atrophy, synaptic failure, cognitive decline, and accumulation of aggregated beta-amyloid peptide. Increasing synaptic acetylcholine in damaged but still functional cholinergic synapses improves cognitive symptoms, whereas increasing the ability of glia to support synapses and to clear beta-amyloid peptide might be disease-modifying. Conversely, chronic glial overactivation can also drive degenerative processes and in butyrylcholinesterase K-variant negative females generalized glial overactivation may be the main driver from mild cognitive impairment to AD. Females are more likely than males to have accelerated age-related myelin breakdown, more widespread white matter loss, loss of neural network connectivity, whole brain atrophy, and functional decline. Increasing extracellular acetylcholine levels blocks glial activation, reduces myelin loss and damage to neural network connectivity, and is disease-modifying. Between extremes characterized by gender, genotype, and age, pathophysiology may be mixed and this spectrum may explain much of the heterogeneity of amnestic mild cognitive impairment. Preservation of the functional integrity of the neural network may be an important component of strengthening cognitive reserve and significantly delaying the onset and progression of dementia, particularly in females. Prospective confirmation of these hypotheses is required. Implications for future research and therapeutic opportunities are discussed.

PI3Ks-drug targets in inflammation and cancer

Phosphoinositide 3-kinases (PI3Ks) control cell growth, proliferation, cell survival, metabolic activity, vesicular trafficking, degranulation, and migration. Through these processes, PI3Ks modulate vital physiology. When over-activated in disease, PI3K promotes tumor growth, angiogenesis, metastasis or excessive immune cell activation in inflammation, allergy and autoimmunity. This chapter will introduce molecular activation and signaling of PI3Ks, and connections to target of rapamycin (TOR) and PI3K-related protein kinases (PIKKs). The focus will be on class I PI3Ks, and extend into current developments to exploit mechanistic knowledge for therapy.

Protein kinase Cι expression and oncogenic signaling mechanisms in cancer

Accumulating evidence demonstrates that PKCι is an oncogene and prognostic marker that is frequently targeted for genetic alteration in many major forms of human cancer. Functional data demonstrate that PKCι is required for the transformed phenotype of lung, pancreatic, ovarian, prostate, colon, and brain cancer cells. Future studies will be required to determine whether PKCι is also an oncogene in the many other cancer types that also overexpress PKCι. Studies of PKCι using genetically defined models of tumorigenesis have revealed a critical role for PKCι in multiple stages of tumorigenesis, including tumor initiation, progression, and metastasis. Recent studies in a genetic model of lung adenocarcinoma suggest a role for PKCι in transformation of lung cancer stem cells. These studies have important implications for the therapeutic use of aurothiomalate (ATM), a highly selective PKCι signaling inhibitor currently undergoing clinical evaluation. Significant progress has been made in determining the molecular mechanisms by which PKCι drives the transformed phenotype, particularly the central role played by the oncogenic PKCι-Par6 complex in transformed growth and invasion, and of several PKCι-dependent survival pathways in chemo-resistance. Future studies will be required to determine the composition and dynamics of the PKCι-Par6 complex, and the mechanisms by which oncogenic signaling through this complex is regulated. Likewise, a better understanding of the critical downstream effectors of PKCι in various human tumor types holds promise for identifying novel prognostic and surrogate markers of oncogenic PKCι activity that may be clinically useful in ongoing clinical trials of ATM.

Expression of cholinesterases in human kidney and its variation in renal cell carcinoma types

Despite the aberrant expression of cholinesterases in tumours, the question of their possible contribution to tumorigenesis remains unsolved. The identification in kidney of a cholinergic system has paved the way to functional studies, but details on renal cholinesterases are still lacking. To fill the gap and to determine whether cholinesterases are abnormally expressed in renal tumours, paired pieces of normal kidney and renal cell carcinomas (RCCs) were compared for cholinesterase activity and mRNA levels. In studies with papillary RCC (pRCC), conventional RCC, chromophobe RCC, and renal oncocytoma, acetylcholinesterase activity increased in pRCC (3.92 ± 3.01 mU·mg(-1), P = 0.031) and conventional RCC (2.64 ± 1.49 mU·mg(-1), P = 0.047) with respect to their controls (1.52 ± 0.92 and 1.57 ± 0.44 mU·mg(-1)). Butyrylcholinesterase activity increased in pRCC (5.12 ± 2.61 versus 2.73 ± 1.15 mU·mg(-1), P = 0.031). Glycosylphosphatidylinositol-linked acetylcholinesterase dimers and hydrophilic butyrylcholinesterase tetramers predominated in control and cancerous kidney. Acetylcholinesterase mRNAs with exons E1c and E1e, 3'-alternative T, H and R acetylcholinesterase mRNAs and butyrylcholinesterase mRNA were identified in kidney. The levels of acetylcholinesterase and butyrylcholinesterase mRNAs were nearly 1000-fold lower in human kidney than in colon. Whereas kidney and renal tumours showed comparable levels of acetylcholinesterase mRNA, the content of butyrylcholinesterase mRNA was increased 10-fold in pRCC. The presence of acetylcholinesterase and butyrylcholinesterase mRNAs in kidney supports their synthesis in the organ itself, and the prevalence of glycosylphosphatidylinositol-anchored acetylcholinesterase explains the splicing to acetylcholinesterase-H mRNA. The consequences of butyrylcholinesterase upregulation for pRCC growth are discussed.

Potential role of PI3K inhibitors in the treatment of breast cancer

In recent years, we have witnessed advances in the understanding of molecular events that lead to breast cancer. This knowledge allowed, among other things, the development of novel therapies that target critical pathways involved in this disease. One of these pathways is the PI3K pathway, whose signaling axis has implications on cancer cell growth, survival, motility and metabolism. In the present review, the potential role of PI3K inhibitors in the treatment of breast cancer is discussed. The fast pace of development of these drugs urges the discussion on the advantages and pitfalls of their application and impact in the future therapy of breast cancer.

Study of abnormal chromosome regions in esophageal squamous cell carcinoma by comparative genomic hybridization: relationship of lymph node metastasis and distant metastasis to selected abnormal regions

Squamous cell carcinoma of the esophagus (ESCC) has a poor prognosis among digestive tract cancers. Lymph node metastasis and distant metastasis are the major factors determining its prognosis. We used comparative genomic hybridization (CGH) to evaluate primary tumor lymph nodes and metastatic areas from ESCC patients in order to determine the relationship between abnormal chromosome regions and outcome. Tumor tissues and lymph nodes were collected from 51 patients with ESCC, and abnormal chromosome regions were detected by CGH. We searched for regions that were significantly more common in patients with lymph nodes metastases (n>/= 6) or distant metastases, and correlated those chromosomal changes with survival. Regions showing amplification in more than 65% of esophageal squamous cell cancers were as follows: 17q12 (90.2%), 17q21 (86.3%), 3q29 (82.4%), 3q28 (78.4%), 8q24.2 (76.5%), 22q12 (76.5%), 3q27 (74.5%), 8q24.3 (74.5%), 1q22 (70.6%), 5p15.3 (70.6%), 22q13 (70.6%), 3q26.3, 8q23, 8q24.1, 9q34, 11q13, 17p12, 17q25, 20q12, 20q13.1 (68.6%), 1q32, 1q42, and 20q13.2 (66.7%). Regions showing deletion in more than 50% of the tumors were as follows: Yp11.3 (62.7%), 3p26 (56.9%), Yq12 (54.9%), 13q21 (52.9%), 4q32 (51.0%), and 13q22 (51.0%). When Fisher's test was used to assess associations of these regions with metastases to lymph nodes, amplification at 2q12-14 (P= 0.012), 3q24-26 (P= 0.005), and 7q21-31 (P= 0.026) were significant. Survival was worse for patients with amplification at all 3 regions. In patients with distant organ metastases, amplification at 7p13-21 was significant (P= 0.008), and survival was worse. Chromosomal amplifications in ESCC at 2q12-14, 3q24-26, and 7q21-31 were associated with lymph node metastasis, while amplification at 7p13-21 was related to distant metastasis. Amplification at these regions correlated with worse survival. Genes involved in the phenotype of ESCC may exist in these regions. Identification of these genes is a theme for future investigation.

Disulfiram treatment facilitates phosphoinositide 3-kinase inhibition in human breast cancer cells in vitro and in vivo

Frequent genetic alterations of the components in the phosphoinositide 3-kinase (PI3K)/PTEN/AKT signaling pathway contribute greatly to breast cancer initiation and progression, which makes targeting this signaling pathway a promising therapeutic strategy for breast cancer treatment. In this study, we showed that in the presence of copper (Cu), disulfiram (DSF), a clinically used antialcoholism drug, could potently inhibit breast cancer cell growth regardless of the PIK3CA status. Surprisingly, the treatment with a mixture of DSF and copper (DSF-Cu) led to the decreased expression of PTEN protein and the activation of AKT in a dose- and time-dependent manner in different cell lines with or without PIK3CA mutations. Treatment of breast cancer cell lines with a combination of DSF-Cu and LY294002, a pan-PI3K inhibitor, resulted in the significant inhibition of cell growth when compared with either drug alone. In addition, the combined treatment of DSF and LY294002 significantly inhibited the growth of the breast tumor xenograft in nude mice induced by MDA-MB-231 cells expressing mutant PIK3CA-H1047R and PIK3CA-E545K, whereas neither DSF nor LY294002 alone could significantly retard tumor growth. Finally, the observed in vivo inhibitory effects are found associated with aberrant signaling alterations and apoptosis-inducing activities in tumor samples. Thus, our finding shows for the first time that treatment of breast cancer with DSF results in a novel feedback mechanism that activates AKT signaling. Our study also suggests that the combination of DSF and a PI3K inhibitor may offer a new combinational treatment model for breast cancer, particularly for those with PIK3CA mutations.

The PI3K pathway as drug target in human cancer

The phosphatidylinositol 3-kinase (PI3K) signaling axis impacts on cancer cell growth, survival, motility, and metabolism. This pathway is activated by several different mechanisms in cancers, including somatic mutation and amplification of genes encoding key components. In addition, PI3K signaling may serve integral functions for noncancerous cells in the tumor microenvironment. Consequently, therapeutics targeting the PI3K pathway are being developed at a rapid pace, and preclinical and early clinical studies are beginning to suggest specific strategies to effectively use them. However, the central role of PI3K signaling in a large array of diverse biologic processes raises concerns about its use in therapeutics and increases the need to develop sophisticated strategies for its use. In this review, we will discuss how PI3K signaling affects the growth and survival of tumor cells. From this vantage, we will consider how inhibitors of the PI3K signaling cascade, either alone or in combination with other therapeutics, can most effectively be used for the treatment of cancer.

PIKing the right isoform: the emergent role of the p110beta subunit in breast cancer

Class IA phosphoinositide-3'-kinases (PI3Ks) regulate many cellular processes. Despite a clear implication of PI3K in cancer, the involvement of each of its isoforms namely p110alpha and p110beta in the development of breast cancer remains elusive. Until recently, the spotlight was given to the alpha subunit; however, the p110beta isoform has now emerged as an interesting target as well. In order to determine the importance of both these subunits in breast cancer, we aimed to study the expression of p110alpha and p110beta in a series of invasive breast carcinomas. We constructed tissue microarrays from 315 invasive breast carcinomas and performed immunohistochemistry for p110alpha and beta, correlating the expression patterns with clinicopathological parameters. Furthermore, overall survival was analysed through Kaplan-Meier survival curves and Cox regression. We found that p110 subunits are expressed in 23.8% of invasive breast carcinomas, of which 11.8% express p110alpha and 15.2% p110beta. The p110alpha positive tumours correlated with hormone receptor (HR) expression, and were not associated with overall survival. The membrane expression of p110beta was associated with worse prognosis. This was due to its link to HER2-overexpression, lower age of onset, higher grade, lymph node involvement, distant metastasis and was inversely associated with HR status. Furthermore, p110beta expression was associated with worse overall survival. Importantly our results indicate a role for the beta subunit in the development/progression of HER2-overexpressing tumours, highlighting possible therapeutic associations between HER2 and p110beta inhibitors.

PIK3CA amplification is predictive of poor prognosis in Tunisian patients with nasopharyngeal carcinoma

PI3Ks (phosphatidylinositol 3-kinases) are lipid kinases that regulate signalling pathways involved in cell proliferation, motility, and adhesion. Somatic mutations and amplification of the PIK3CA gene have been reported in various types of human cancers. However, little is known about the frequency and prognosis role of PIK3CA activation in nasopharyngeal carcinoma (NPC). This study was conducted with the aim to screen for PIK3CA mutations in the two hot spot regions (exons 9 and 20) and to investigate for the PIK3CA gene amplification combined with the expression analysis of the phosphorylated Akt (pAkt). We showed that among 88 specimens, none had mutation in the helical domain (exon 9) and only one (1.13%) had mutation in the kinase domain (exon 20). On the other hand, PIK3CA gene amplification was found in 21.6% of cases and was strongly associated with distant metastasis (P = 0.002), lymph node involvement (P = 0.032), and advanced tumor stage (P < 0.001). Moreover, patients with PIK3CA copy number gain have a significant reduced overall survival time (P log rank = 0.02). We concluded that PIK3CA gene amplification is frequent in NPC and occurs in the advanced stage of NPC. Moreover, our finding emphasizes the association of PIK3CA gene amplification with worse prognosis in nasopharyngeal carcinoma.

DNA profiling by array comparative genomic hybridization (CGH) of peripheral blood mononuclear cells (PBMC) and tumor tissue cell in non-small cell lung cancer (NSCLC)

Lung tumor cell DNA copy number alteration (CNA) was expected to display specific patterns such as a large-scale amplification or deletion of chromosomal arms, as previously published data have reported. Peripheral blood mononuclear cell (PBMC) CNA however, was expected to show normal variations in cancer patients as well as healthy individuals, and has thus been used as normal control DNA samples in various published studies. We performed array CGH to measure and compare genetic changes in terms of the CNA of PBMC samples as well as DNA isolated from tumor tissue samples, obtained from 24 non-small cell lung cancer patients. Contradictory to expectations, our studies showed that the PBMC CNA also showed chromosomal variant regions. The list included well-known tumor-associated NTRK1, FGF8, TP53, and TGFbeta1 genes and potentially novel oncogenes such as THPO (3q27.1), JMJD1B, and EGR1 (5q31.2), which was investigated in this study. The results of this study highlighted the connection between PBMC and tumor cell genomic DNA in lung cancer patients. However, the application of these studies to cancer prognosis may pose a challenge due to the large amount of information contained in genetic predisposition and family history that has to be processed for useful downstream clinical applications.

Genomic aberrations in squamous cell lung carcinoma related to lymph node or distant metastasis

About 50% of patients presenting with resectable lung cancer develop distant metastases within 5 years. Genomic markers predicting metastatic behaviour of squamous cell lung carcinoma (SCC) are currently underexposed. We analyzed a cohort of patients with primary SCC using array-based comparative genomic hybridization (aCGH) to identify which genomic aberrations are related to metastatic behaviour. The cohort consisted of 34 patients with a follow-up of at least 5 years, 8 with metastases in regional lymph nodes only and 26 patients without any metastases at the time of surgery. Eleven of the latter 26 developed metastases in distant organs within 3 years after surgery. Copy number changes observed in at least 40% of all SCC included gains at chromosomal arms 3q, 5p, 8q, 19q, 20p, 22q and losses at 3p, 4p, 4q, 5q, 8p and 9p. High copy number amplifications were observed at 2p15-p16, 3q24-q29, 8p11-p12, 8q23-q24, and 12p12, containing candidate oncogenes such as BCL11A, REL, ECT2, PIK3CA, ADAM9, MYC and KRAS. Amplification of 2p15-p16 is a novel finding in SCC. Another novel finding is the homozygous deletion observed at 4q33-34.1 in 15% of the SCC cases. Gains at 7q36, 8p12, 10q22, 12p12, loss at 4p14 and the homozygous deletions at 4q occurred significantly more frequent in SCC from patients with lymph node metastases only. SCC from patients with distant metastases showed a significantly higher gain frequency at 8q22-q24 and loss at 8p23 and 13q21, and a significantly lower gain frequency at 2p12 and 2p16 and loss at 11q25 compared with SCC from patients without metastases. Of these, gains at 7q, 8p and 10q were restricted to SCC with lymph node metastasis and gain at 8q was restricted to patients with distant metastasis. Two genomic aberrations, i.e. loss of 4p and gain of 19q12 were observed more frequently in SCC with only lymph node metastases as compared to SCC with distant metastases. In conclusion, we identified genomic aberrations in primary SCC that were related to lymph node or distant metastases.

Ski and SnoN, potent negative regulators of TGF-beta signaling

Ski and the closely related SnoN were discovered as oncogenes by their ability to transform chicken embryo fibroblasts upon overexpression. While elevated expressions of Ski and SnoN have also been reported in many human cancer cells and tissues, consistent with their pro-oncogenic activity, emerging evidence also suggests a potential anti-oncogenic activity for both. In addition, Ski and SnoN have been implicated in regulation of cell differentiation, especially in the muscle and neuronal lineages. Multiple cellular partners of Ski and SnoN have been identified in an effort to understand the molecular mechanisms underlying the complex roles of Ski and SnoN. In this review, we summarize recent findings on the biological functions of Ski and SnoN, their mechanisms of action and how their levels of expression are regulated.

Genomic changes in progression of low-grade gliomas

Using a one-megabase BAC-based array comparative genomic hybridization technique (aCGH), we have investigated a series of 16 low-grade gliomas (LGGs) and their subsequent progression to higher-grade malignancies. The most frequent chromosome imbalances in primary tumors were gains of chromosomes 7q, 8q, and 22q, and losses of chromosomes 1p, 13q, and 19q. In tumor progression, gains of chromosomes 11q, 7q, 20q, and 21q, and losses of chromosomes 9p, including CDKN2A locus, 19q, 14q, 1p, and 6q were the most frequent genomic disequilibria. Progressive tumors were more imbalanced than primary tumors in terms of altered chromosomal arms (3.8 vs. 6.6 in mean abnormal chromosomal arm) and altered BACs (17 vs. 21%). Interestingly, putative novel candidate genes associated with glioma progression were identified, in particular DOCK8, PTPRD, CER1, TPHO, DHFR, MSH3, ETS1, ACACA, and CSE1L.

PIK3CA mutation status in Japanese esophageal squamous cell carcinoma

BACKGROUND

A somatic mutation of the PIK3CA (phosphatidylinositol 3-kinase catalytic subunit) gene has been found in human cancer patients. However, this mutation has not yet been extensively studied in esophageal squamous cell carcinomas.

MATERIALS AND METHODS

We analyzed a mutation of the PIK3CA gene in 88 Japanese cases of esophageal squamous cell carcinomas that had all undergone surgery at the Department of Surgery II, Nagoya City University Medical School, between 1996 and 2003. The TE and KYSE series of cell lines are human esophageal cancer cell lines. Two PIK3CA mutation hot spots (exon 9 and exon 20) were analyzed by a real time polymerase chain reaction (PCR)-based assay and the data were confirmed by direct sequencing. We performed a cell proliferation assay to determine the effects of a PI3K inhibitor LY294002.

RESULT

In exon 9, a somatic mutation was found in two patients (2.2%) and in two cell lines. The mutations included three E545K (G1633A) mutations and one E545Q (G1633C) mutation. However, in exon 20, no mutation was observed in our esophageal cancer patients. PI3K inhibitor (LY294002) inhibited the growth of an esophageal cancer cell line with a PIK3CA mutation (E545K) in vitro.

CONCLUSIONS

We found LY294002 to reduce the proliferation of the esophageal cancer cell line in vitro. Importantly, a cell line with a PIK3CA gene mutation was more susceptible to a PI3K inhibition than those without any such mutation. Further functional analyses of the PIK3CA mutations are warranted to determine whether or not they may be potentially useful targets of therapy for esophageal cancer.

Comprehensive analysis of oncogenic effects of PIK3CA mutations in human mammary epithelial cells

More than 20 different PIK3CA gene mutations were identified in breast cancer with different frequencies. Whether these breast cancer associated mutations have similar biological effects is largely unknown. In this study, we established a novel cell model using the lentivirus system to express 10 different PIK3CA genes (wild type and mutant) based on the human mammary epithelial cell MCF10A. We found that nine different PIK3CA mutants harbor different abilities to promote cell proliferation and EGF independent growth. In addition, most PIK3CA mutants (except for the wild type PIK3CA, the Q60K and the K111N mutants) had the ability to change the morphogenesis of the MCF10A cell in 3D Matrigel assay. Moreover, different PIK3CA mutants have different abilities to promote colony formation and cell invasion. We further observed that most of the PIK3CA mutants could activate p-AKT and p-p70-S6K in the absence of EGF stimulation. Finally, LY294002, a PI3K inhibitor, can effectively inhibit cell growth in cell lines with different PIK3CAs. Taken together, our results support the notion that different PIK3CA mutations differentially contribute to breast cancer transformation, and exploration of the therapeutic application of these mutations will benefit breast cancer patients with the PIK3CA mutations.

Targeting phosphoinositide 3-kinase: moving towards therapy

Phosphoinositide 3-kinases (PI3K) orchestrate cell responses including mitogenic signaling, cell survival and growth, metabolic control, vesicular trafficking, degranulation, cytoskeletal rearrangement and migration. Deregulation of the PI3K pathway occurs by activating mutations in growth factor receptors or the PIK3CA locus coding for PI3Kalpha, by loss of function of the lipid phosphatase and tensin homolog deleted in chromosome ten (PTEN/MMAC/TEP1), by the up-regulation of protein kinase B (PKB/Akt), or the impairment of the tuberous sclerosis complex (TSC1/2). All these events are linked to growth and proliferation, and have thus prompted a significant interest in the pharmaceutical targeting of the PI3K pathway in cancer. Genetic targeting of PI3Kgamma (p110gamma) and PI3Kdelta (p110delta) in mice has underlined a central role of these PI3K isoforms in inflammation and allergy, as they modulate chemotaxis of leukocytes and degranulation in mast cells. Proof-of-concept molecules selective for PI3Kgamma have already successfully alleviated disease progress in murine models of rheumatoid arthritis and lupus erythematosus. As targeting PI3K moves forward to therapy of chronic, non-fatal disease, safety concerns for PI3K inhibitors increase. Many of the present inhibitor series interfere with target of rapamycin (TOR), DNA-dependent protein kinase (DNA-PK(cs)) and activity of the ataxia telangiectasia mutated gene product (ATM). Here we review the current disease-relevant knowledge for isoform-specific PI3K function in the above mentioned diseases, and review the progress of >400 recent patents covering pharmaceutical targeting of PI3K. Currently, several drugs targeting the PI3K pathway have entered clinical trials (phase I) for solid tumors and suppression of tissue damage after myocardial infarction (phases I,II).

PIK3CA gene amplification in Japanese non-small cell lung cancer

We have investigated 92 non-small cell lung cancer tissues and found 11 PIK3CA amplification. PIK3CA amplification incidence was significantly higher in male, smoker and squamous cell carcinoma patients. Among 11 patients with PIK3CA amplification, two patients harbored a PIK3CA mutation. There was significant difference in survival between the patients with PIK3CA normal copy number and the patients with PIK3CA amplification.

3q26 Amplification and polysomy of chromosome 3 in squamous cell lesions of the lung: a fluorescence in situ hybridization study

PURPOSE

An overlapping area of gain at 3q26 has been reported in lung squamous cell carcinoma (SCC), but whether this also occurs in preneoplastic/preinvasive squamous cell proliferations and early-stage invasive carcinomas of the lung is still unknown.

EXPERIMENTAL DESIGN

We evaluated the prevalence and the clinicopathologic implications of 3q26 amplification and polysomy of chromosome 3 in 31 preneoplastic/preinvasive squamous cell lesions of the bronchial mucosa and in 139 early-stage invasive pulmonary SCC, both of limited growth within the bronchial wall [early hilar SCC (EHSCC)] and involving the pulmonary parenchyma [parenchyma-infiltrating SCC (PISCC)]. Moreover, mRNA expression of two candidate genes (h-TERC and SKI-like), both mapping to the minimal common amplification region, was also studied by quantitative real-time reverse transcription-PCR.

RESULTS

3q26 amplification and polysomy of chromosome 3 were confined to malignant samples, with 37% of invasive SCC, and 27% of severe dysplasias/in situ carcinomas showing these chromosomal abnormalities. Amplification (with minimal common amplification region at 3q26.2), polysomy 3, concurrent amplification and polysomy 3, or other changes (monosomy) were found in 25 SCC and 1 dysplasia, 24 and 2, 2 and 0, and 1 and 0, respectively. Amplification was significantly associated with EHSCC, polysomy 3 with PISCC. 3q26 amplification correlated with increased tumor diameter and a history of smoking, whereas polysomy 3 correlated with tumor diameter, pT class, and p53, p21, and fascin immunoreactivity. No relationship of either 3q26 gain or polysomy was found with patients' survival. Overexpression of h-TERC or SKI-like mRNA was found in 3q26-amplified or polysomic SCC, with higher levels of h-TERC in the former and of SKI-like in the latter.

CONCLUSIONS

3q26 amplification and chromosome 3 polysomy may be related to the development of invasive SCC, with differential distribution in tumor subsets, despite substantial histologic uniformity. Both h-TERC and SKI-like may be involved in tumor progression.

PIK3CA mutation status in Japanese lung cancer patients

Somatic mutations of the PIK3CA (phosphatidylinostitol 3-kinase catalytic subunit) gene have been found in human cancer patients. Previous reports suggested that about 4% of lung cancers harbored PIK3CA gene mutations. However, the clinico-pathological background for PIK3CA gene mutations has not yet been investigated in lung cancer. We have genotyped the PIK3CA gene in Japanese lung cancer patients. The study included 235 lung cancer cases surgically removed in Nagoya City University Hospital. The two PIK3CA mutation hot spots (exon 9 and exon 20) were analyzed by real time polymerase chain reaction (PCR)-based assay. The data were confirmed by direct sequencing. In exon 9, somatic mutation was found in eight patients (3.4%). The mutation included three E542K (G1624A), three E545K (G1633A), one E542Q (G1624C), and one Q546K (C1636A). However, in exon 20, there was no mutation in our lung cancer patients. PIK3CA mutations were not correlated with gender (women versus men, p=0.4162), age (< or =60 versus >60, p=0.8027), or smoking status of the lung cancers (never versus smoker, p=0.5666). PIK3CA mutation incidence was significantly lower in adenocarcinoma (2/135, 1.5%) than in squamous cell carcinoma (5/77, 6.5%, p=0.0495). Among eight patients with a PIK3CA mutation, three patients also harbored an EGFR somatic mutation. PIK3CA gene mutations were rare in lung cancer; rarer in adenocarcinoma. Further functional analyses of the PIK3CA mutations are warranted to study if they could be the target of therapy for the lung cancer.

PIK3CA and TFRC Located in 3q Are New Prognostic Factors in Esophageal Squamous Cell Carcinoma

BACKGROUND

Amplification of the chromosome 3q seems to occur frequently in esophageal squamous cell carcinoma (ESCC). This study analyzed the clinical effect of messenger RNA (mRNA) expression for PIK3CA (the gene that encodes phosphatidylinositol-3 kinase catalytic alpha-polypeptide) and TFRC (the gene that encodes the transferrin receptor), which map within chromosome 3q in ESCC.

METHODS

Formalin-fixed, paraffin-embedded ESCC tissues were examined. Total RNAs were extracted, and reverse transcription products were subjected to polymerase chain reaction amplification of beta-actin, PIK3CA, and TFRC.

RESULTS

Expression of beta-actin mRNA was detected in 67 (55.8%) of 120 samples, with PIK3CA mRNA expression in 22 (32.8%) of these 67 samples and TFRC mRNA expression in 15 (22.4%) of the 67 samples. PIK3CA mRNA expression correlated with regional lymph node metastasis (P = .04). TFRC mRNA expression correlated with distant metastasis (P = .04). Patients with positive results for either PIK3CA or TFRC mRNA displayed a significantly worse prognosis than patients with negative results (PIK3CA, P = .045; TFRC, P = .009). TFRC mRNA expression represented an independent prognostic factor in multivariate analysis (P = .0233), but PIK3CA did not (P = .7585).

CONCLUSIONS

PIK3CA and TFRC mRNA represent prognostic factors in patients with ESCC. TFRC mRNA offers an independent prognostic factor, and expression may have clinically important implications.

DNA copy number gains in head and neck squamous cell carcinoma

Gene amplification, a common mechanism for oncogene activation in cancer, has been used as a tag for the identification of novel oncogenes. DNA amplification is frequently observed in head and neck squamous cell carcinoma (HNSCC) and potential oncogenes have already been reported. We applied restriction landmark genome scanning (RLGS) to study gene amplifications and low-level copy number changes in HNSCC in order to locate previously uncharacterized regions with copy number gains in primary tumor samples. A total of 63 enhanced RLGS fragments, indicative of DNA copy number changes, including gains of single alleles, were scored. Enhanced sequences were identified from 33 different chromosomal regions including those previously reported (e.g. 3q26.3 and 11q13.3) as well as novel regions (e.g. 3q29, 8q13.1, 8q22.3, 9q32, 10q24.32, 14q32.32, 17q25.1 and 20q13.33). Furthermore, our data suggest that amplicons 11q13.3 and 3q26.3-q29 may be divided into possibly two and three independent amplicons, respectively, an observation supported by published microarray expression data.

Evi1 is a survival factor which conveys resistance to both TGFbeta- and taxol-mediated cell death via PI3K/AKT

In hematopoietic cells the transforming potential of the ecotropic viral integration site 1 (Evi1) oncogene is thought to be dependent upon the ability to inhibit TGFbeta signaling. Although Evi1 has recently been implicated in certain epithelial cancers, the effects of Evi1 on transformation and TGFbeta signaling in epithelial cells are not completely understood. Herein, we have determined the effects of Evi1 on TGFbeta signaling in intestinal epithelial cells. Stable expression of Evi1 in non-transformed intestinal epithelial cells inhibited induction of some Smad3-dependent TGFbeta target genes, such as PAI1. However, TGFbeta-mediated induction of cellular adhesion signaling components such as integrin1 and paxillin was not inhibited by Evi1; nor did Evi1 inhibit TGFbeta-mediated epithelial to mesenchymal transition. Likewise, Evi1 did not inhibit TGFbeta-mediated downregulation of cyclin D1 or block TGFbeta-mediated growth inhibition. However, Evi1 did inhibit TGFbeta-mediated apoptosis by a process that involves phosphoinositide-3-kinase (PI3K) and its downstream effector AKT. The ability of Evi1 to suppress apoptosis is not restricted to TGFbeta-mediated cell death, since Evi1 also protects intestinal epithelial cells from taxol-mediated apoptosis. Evi1 is overexpressed in some human colon cancer cell lines, and overexpression is associated with amplification of the Evi1 gene. Knockdown of Evi1 by siRNA inhibited AKT phosphorylation in HT-29 human colon cancer cells and increased their sensitivity to taxol-mediated apoptosis. These data indicate that Evi1 functions as a survival gene in intestinal epithelial cells and colon cancer cells, activating PI3K/AKT and conveying resistance to both physiological and therapeutic apoptotic stimuli.

Overexpression of LAMP3/TSC403/DC-LAMP promotes metastasis in uterine cervical cancer

LAMP3 (DC-LAMP, TSC403, CD208) was originally isolated as a gene specifically expressed in lung tissues. LAMP3 is located on a chromosome 3q segment that is frequently amplified in some human cancers, including uterine cervical cancer. Because two other members of the LAMP family of lysosomal membrane glycoproteins, LAMP1 and LAMP2, were previously implicated in potentially modulating the interaction of vascular endothelial and cancer cells, we hypothesized that LAMP3 might also play an important part in metastasis. To clarify the metastatic potential of LAMP3 in cervical cancers, we transfected a LAMP3 expression vector into a human uterine cervical cancer cell line, TCS. In an in vitro invasion assay, the migration of LAMP3-overexpressing TCS cells was significantly higher than in control TCS cells. In an in vivo metastasis assay, distant metastasis was detected in 9 of 11 LAMP3-overexpressing TCS cell-injected mice and in only 1 of 11 control mice. Histologic study showed that LAMP3-overexpressing cells readily invaded into the lymph-vascular space. In clinical samples, quantitative real-time reverse transcription-PCR (RT-PCR) analyses showed that LAMP3 mRNA was significantly up-regulated in 47 of 47 (100%) cervical cancers and in 2 of 15 (13%) cervical intraepithelial neoplasias, compared with a low level of LAMP3 mRNA expressed in normal uterine cervixes. Interestingly, high LAMP3 expression was significantly correlated with the overall survival of patients with stage I/II cervical cancers. These findings indicate that LAMP3 overexpression is associated with an enhanced metastatic potential and may be a prognostic factor for cervical cancer.

Construction of single chain Fv antibody against transferrin receptor and its protein fusion with alkaline phosphatase

AIM: To construct fusion protein of a single-chain antibody (scFv) against transferrin receptor (TfR) with alkaline phosphatase (AP).

METHODS: The VH-linker-VL, namely scFv gene, was prepared by amplifying the VH and VL genes from plasmid pGEM-T-VH and pGEM-T-VL with splicing overlap extension polymerase chain reaction (SOE PCR). After the ScFv gene was modified by Sfi I and Not I, it was subcloned into the secretory expression vector pUC19/119, and then was transformed into E.coli TG1. The positive colonies were screened by colony PCR and their expressions were induced by IPTG. ScFv gene was gained by digesting ScFv expression vector pUC19/119 with Sfi I and Not I restriction enzymes, then subcloned into expression vector pDAP2, followed by transformation in E.coli TG1. The positive colonies were selected by bacterial colony PCR. The expression of fusion protein (scFv-AP) was induced by IPTG. Its activity was detected by enzyme immunoassay. The molecular weights of scFv and scFv-AP were measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

RESULTS: The product of SOE PCR formed a band of 700 bp in agarose gel electrophoresis. SDS-PAGE demonstrated the molecular weight of scFv was 27 ku. Immunofluorescent assay (IFA) demonstrated its reactivity with TfR. The molecular weight of scFv-AP was 75 ku. Enzyme immunoassay showed that scFv-AP could specifically bind to human TfR and play AP activity.

CONCLUSION: We have successfully prepared the anti-human TfR scFv and constructed the fusion protein of scFv and AP. It is promising for immunological experiments.

PIK3CA mutations in glioblastoma multiforme

Glioblastoma multiforme WHO grade IV is the most common and malignant variant of astrocytic tumors. Loss of heterozygosity of chromosome 10 and mutations in the tumor suppressor gene PTEN on 10q are molecular hallmarks of glioblastomas. Recently, mutations were identified in PIK3CA, encoding a protein that antagonizes the function of PTEN protein in the PI3K/Akt pathway. To address the question whether an exclusive mutation pattern can be observed in PIK3CA and PTEN, we determined the frequency of mutations in both genes. All coding exons were examined by single strand confirmation polymorphism and direct sequencing. Additionally, we analyzed chromosome 10 for loss of heterozygosity and evaluated the mutational status of TP53. In 70 glioblastomas, 5 (7%) PIK3CA mutations and 10 (14%) PTEN mutations were found. All mutations in PIK3CA located to exons 1, 9 and 20, thereby supporting the concept of mutational hot spot regions. In all but one glioblastoma, mutations were seen either in PIK3CA or in PTEN. In conclusion, the frequency of PIK3CA mutations in glioblastomas appears to be much lower than initially reported.

Somatic mutation and gain of copy number of PIK3CA in human breast cancer

Introduction

Phosphatidylinositol 3-kinases (PI3Ks) are a group of lipid kinases that regulate signaling pathways involved in cell proliferation, adhesion, survival, and motility. Even though PIK3CA amplification and somatic mutation have been reported previously in various kinds of human cancers, the genetic change in PIK3CA in human breast cancer has not been clearly identified.

Methods

Fifteen breast cancer cell lines and 92 primary breast tumors (33 with matched normal tissue) were used to check somatic mutation and gene copy number of PIK3CA. For the somatic mutation study, we specifically checked exons 1, 9, and 20, which have been reported to be hot spots in colon cancer. For the analysis of the gene copy number, we used quantitative real-time PCR and fluorescence in situ hybridization. We also treated several breast cancer cells with the PIK3CA inhibitor LY294002 and compared the apoptosis status in cells with and without PIK3CA mutation.

Results

We identified a 20.6% (19 of 92) and 33.3% (5 of 15) PIK3CA somatic mutation frequency in primary breast tumors and cell lines, respectively. We also found that 8.7% (8 of 92) of the tumors harbored a gain of PIK3CA gene copy number. Only four cases in this study contained both an increase in the gene copy number and a somatic mutation. In addition, mutation of PIK3CA correlated with the status of Akt phosphorylation in some breast cancer cells and inhibition of PIK3CA-induced increased apoptosis in breast cancer cells with PIK3CA mutation.

Conclusion

Somatic mutation rather than a gain of gene copy number of PIK3CA is the frequent genetic alteration that contributes to human breast cancer progression. The frequent and clustered mutations within PIK3CA make it an attractive molecular marker for early detection and a promising therapeutic target in breast cancer.

A chemically induced model for squamous cell carcinoma of the lung in mice: histopathology and strain susceptibility

Lung cancer, primarily associated with tobacco use, is the leading cause of cancer morbidity and mortality in the United States. Squamous cell carcinoma (SCC) is one of the four major histological types of lung cancer. Although there are several established models for lung adenoma and adenocarcinomas, there is no well-established mouse model for lung SCC. We treated eight different inbred strains of mice with N-nitroso-tris-chloroethylurea by skin painting and found that this regimen induced lung SCCs in five strains of mouse (SWR/J, NIH Swiss, A/J, BALB/cJ, and FVB/J) but not in the others (AKR/J, 129/svJ, and C57BL/6J). Mouse lung SCCs have similar histopathological features and keratin staining to human SCC. Moreover, a wide spectrum of abnormal lung squamous phenotypes including hyperplasia, metaplasia, carcinoma in situ, and invasive carcinoma, were observed. There are strain-specific differences in susceptibility to Lscc induction by N-nitroso-tris-chloroethylurea with NIH Swiss, A/J, and SWR/J mice developing scores of SCCs whereas the resistant strains AKR/J, 129/svJ, and C57BL/6J failed to develop any SCCs. FVB/J and BALB/cJ mice had an intermediate response. We conducted whole-genome linkage disequilibrium analysis in seven strains of mice, divided into three phenotype categories of susceptibility, using Fisher's exact test applied to 6,128 markers in publically available databases. Three markers were found significantly associated with susceptibility to SCC with the P < 0.05. They were D1Mit169, D3Mit178, and D18Mit91. Interestingly, none of these sites overlap with the major susceptibility loci associated with lung adenoma/adenocarcinoma development in mice. The mouse SCC described here is highly significant for preclinical studies of lung cancer chemopreventive agents because most human trials have been conducted against precancerous lesions for SCC. Furthermore, this model can be used in determining genetic modifiers that contribute to susceptibility or resistance to lung SCC development.

Genetic alterations in cervical carcinomas: frequent low-level amplifications of oncogenes are associated with human papillomavirus infection

The development of cervical carcinoma is closely associated with HPV infection. However, other genetic alterations also play an important role. In this study, we analyzed copy number alterations of several oncogene loci in a panel of 84 cervical tumors. Sixty-five (77%) tumors were HPV DNA-positive, and most were infected with type 16 or type 18 or both. The oncogenes studied include PIK3CA at 3q26.3, TERT at 5p15.33, C-MYC at 8q24, CCND1 at 11q13.3, ERBB2 at 17q21.2 and locus region 20q13.2. Amplification of 1 or more genes was detected in 55 (65%) cases using interphase FISH. PIK3CA was amplified in 43% of tumors, followed by TERT (33%), 20q13.2 (30%), ERBB2 (29%), C-MYC (25%) and CCND1 (12%). Most tumors showed low-level amplification with 3-7 copies of these genes, and complex changes involving 3 or more genes occur more frequently in tumors at advanced stages. Increased protein expression of c-erbB2 and c-myc was observed in tumors with the corresponding gene amplification. Oncogene alterations were found more often in HPV-infected cases, particularly for C-MYC and TERT. These findings indicate that HPV-associated cervical carcinomas bear frequent alterations of these genes, which may have critical biologic impact on the development and progression of carcinoma of the uterine cervix.

Differentially regulated genes as putative targets of amplifications at 20q in ovarian cancers

Frequent amplification of DNA at 20q or part of 20q has been demonstrated by comparative genomic hybridization in ovarian cancer (OC), but the genetic target(s) of these amplification events remain unknown. We examined copy-number changes with respect to six candidate genes, E2F1 (20q11.2), TGIF2 (20q11.2), AIB1 (20q12), PTPN1 (20q13.1), ZNF217 (20q13.2), and BTAK (20q13), and then measured transcription levels of each candidate in 18 OC cell lines. Three distinct cores of amplification were identified: 20q11.2, harboring E2F1 and TGIF2 (region I; 1 of 18 cell lines, 5.6%); 20q13.1, harboring PTPN1 (region II; 5 lines, 27.8%); and 20q13.2, harboring ZNF217 and BTAK (region III; 6 lines, 33.3%). Among the six genes examined, expression levels of PTPN1 and ZNF217 were significantly correlated with absolute copy-number, and those of PTPN1 and TGIF2 were significantly correlated with copy-number relative to the centromere of chromosome 20 (20cen). Among 19 primary OCs examined, moreover, we observed amplification of TGIF2, PTPN1 and ZNF217 in five (26.3%), ten (52.6%), and twelve (63.2%) tumors, respectively. Expression levels of PTPN1 and ZNF217 were significantly correlated with their copy-numbers in those primary OCs. Our results suggest that 20q amplifications in OCs can be extensive and complex, probably due to synergistic or non-synergistic amplification of separate regions of 20q, involving multiple, independently amplified targets.

Cellular function of phosphoinositide 3-kinases: implications for development, homeostasis, and cancer

The phosphoinositide 3-kinase (PI3K) family of enzymes is recruited upon growth factor receptor activation and produces 3' phosphoinositide lipids. The lipid products of PI3K act as second messengers by binding to and activating diverse cellular target proteins. These events constitute the start of a complex signaling cascade, which ultimately results in the mediation of cellular activities such as proliferation, differentiation, chemotaxis, survival, trafficking, and glucose homeostasis. Therefore, PI3Ks play a central role in many cellular functions. The factors that determine which cellular function is mediated are complex and may be partly attributed to the diversity that exists at each level of the PI3K signaling cascade, such as the type of stimulus, the isoform of PI3K, or the nature of the second messenger lipids. Numerous studies have helped to elucidate some of the key factors that determine cell fate in the context of PI3K signaling. For example, the past two years has seen the publication of many transgenic and knockout mouse studies where either PI3K or its signaling components are deregulated. These models have helped to build a picture of the role of PI3K in physiology and indeed there have been a number of surprises. This review uses such models as a framework to build a profile of PI3K function within both the cell and the organism and focuses, in particular, on the role of PI3K in cell regulation, immunity, and development. The evidence for the role of deregulated PI3K signaling in diseases such as cancer and diabetes is reviewed.

Comparative genomic hybridization of esophageal squamous cell carcinoma: correlations between chromosomal aberrations and disease progression/prognosis

BACKGROUND

Esophageal carcinoma is a major cause of cancer-related deaths among males in Taiwan. However, to date, the genetic alterations that accompany this lethal disease are not understood.

METHODS

Chromosomal aberrations of 46 samples of esophageal squamous cell carcinoma (EC-SCC) were analyzed by comparative genomic hybridization (CGH), and their correlations with pathologic staging and prognosis were analyzed statistically.

RESULTS

In total, 321 gains and 252 losses were found in 46 tumor samples; thus, the average gains and losses per patient were 6.98 and 5.47, respectively. Frequent gain abnormalities were found on chromosome arms 1q, 2q, 3q, 5p, 7p, 7q, 8q, 11q, 12p, 12q, 14q, 17q, 20q, and Xq. Frequent deletions were found on chromosome arms 1p, 3p, 4p, 5q, 8p, 9p, 9q, 11q, 13q, 16p, 17p, 18q, 19p, and 19q. It was found that deletions of 4p and 13q12-q14 and gain of 5p were significantly correlated with pathologic staging. Losses of 8p22-pter and 9p also were found more frequently in patients with advanced disease. Gain of 8q24-qter was seen more frequently in patients with Grade 3 tumors. A univariate analysis found that pathologic staging; gains of 5p and 7q; and deletions of 4p, 9p, and 11q were significant prognostic factors. However, pathologic staging became the only significant factor in a multivariate analysis.

CONCLUSIONS

CGH not only revealed novel chromosomal aberrations in EC-SCC, but also found possible genotypic changes associated with disease progression. Despite all of the possible associations of chromosomal aberrations with disease progression, the most important prognostic factor for patients with EC-SCC was pathologic staging.

Frequent gain of copy number on the long arm of chromosome 3 in human cervical adenocarcinoma

We analyzed genomic aberrations in 20 cervical adenocarcinomas by comparative genomic hybridization (CGH). Most tissue samples (85%) showed DNA copy number changes; gains were more common than losses. The most consistent region of chromosomal gain was mapped to chromosome arm 3q, found in 70% of the cases, with a minimal common region of 3q28-ter. Other recurrent amplifications of genetic material were detected on 17q (45%), 1p (30%), 1q (25%), and 11q (20%). High-level copy number increases were found in chromosomal regions 3q27-ter and 9pter-13. DNA losses were seldom observed, occurring primarily in underrepresented regions of chromosome arms 4q, 13q, and 18q. The presence of high-risk human papilloma virus genomes in the cervical adenocarcinoma samples was detected in 90% of the cases. However, there was no correlation between human papilloma virus type and the pattern of genomic changes. This study is the first report of CGH analysis in human cervical adenocarcinoma. Among the major genomic alterations, our results demonstrate the importance of DNA copy increases of chromosome arm 3q in the development of cervical adenocarcinoma and identify other amplified chromosomal regions that are also associated with cervical carcinogenesis.

SNO is a probable target for gene amplification at 3q26 in squamous-cell carcinomas of the esophagus

Amplification of the 3q26 region appears to occur frequently among esophageal squamous cell carcinomas (ESCs). We examined ESC cell lines for amplification and expression levels of four genes in this region: SNO and EVI1, which encode proteins antagonizing transforming growth factor-beta signaling, and two other putative target genes, TERC and PIK3CA. Amplification of SNO was accompanied by significant increases in its expression level, suggesting that this gene is activated in an amplification-dependent manner. SNO was also amplified in 5 of 44 primary ESCs (11.4%). However, expression levels of EVI1, TERC, and PIK3CA did not correlate with their copy-numbers, even though EVI1 and TERC showed the same amplification pattern as SNO. Taken together, the data suggest that of the four candidates, SNO is the most probable target in the 3q26 amplicon for involvement in the progression of ESC.

A novel amplicon at 9p23 - 24 in squamous cell carcinoma of the esophagus that lies proximal to GASC1 and harbors NFIB

The non-random amplification of DNA at 9p23 - 24 observed in various types of human cancers, including esophageal squamous cell carcinomas (ESCs), may reflect the locations of important tumor-associated genes. Our previous studies using ESC cell lines defined an amplicon in this region and identified a novel gene, GASC1, as a target of the amplification. Since different regions within the same chromosome arm are often involved in amplification in a syntenic or non-syntenic manner, we characterized the amplicon at 9p23 - 24 in 35 ESC cell lines (29 KYSE series and 6 YES series), and examined possible involvement of non-syntenic amplifications at 9p23 - 24 in 32 primary ESCs. Our results clearly indicated that two target regions for DNA amplification exist at 9p23 - 24; the major amplicon contains GASC1, and the minor one harbors a transcription factor, NFIB, centromeric to the GASC1 locus.