bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract C55: Involvement of oxidative stress in the antitumor effect of mTOR inhibitors in mantle cell lymphoma
Authors: Tardif Heather L. , Tome Margaret E. , Briehl Margaret M.
Published: May 2012

Existing treatments for mantle cell lymphoma (MCL) are non-curative, demonstrating a need for a refined treatment approach. MCLs are aggressive lymphomas, usually characterized by over-expression of cyclin D1. Recent clinical trials have shown promising results with the use of mammalian target of rapamycin (mTOR) inhibitors. While cyclin D1 can be regulated through the mTOR pathway, treatment with mTOR inhibitors often inhibit MCL growth without altering cyclin D1. Thus, the anti-tumor activity of mTOR inhibitors is likely mediated through other key targets. One potential target is C/EBPβ-LIP, a transcription factor regulated through the mTOR pathway. One target of C/EBPβ gene regulation is manganese superoxide dismutase (MnSOD), an antioxidant defense enzyme with tumor suppressor activity in some cell types. MnSOD catalyzes the dismutation of superoxide to hydrogen peroxide. Thus, it removes one form of reactive oxygen species (ROS) while generating another. Previous studies in our laboratory have shown that C/EBPβ-LIP levels decrease with mTOR inhibitor treatment in proportion to increasing MnSOD levels. We hypothesize that the anti-tumor effect of mTOR inhibitors in MCL is mediated by the increase in MnSOD protein expression and accumulation of ROS, specifically hydrogen peroxide. Here we investigated the effect of rapamycin on MnSOD and the levels of ROS in two human MCL-derived cell lines. High MnSOD levels correlated with increased sensitivity of cells treated with rapamycin. To investigate the biological effects of increased MnSOD expression, we measured overall ROS levels (DCFH) and the rate of hydrogen peroxide efflux with the fluorescent probe Amplex Red, which is indicative of changes to hydrogen peroxide levels in the cells. These results showed that both overall ROS and hydrogen peroxide levels increased in parallel with MnSOD expression. These increases in hydrogen peroxide were not due to decreased levels of catalase or glutathione peroxidase. Treatment with the general ROS scavenger, N-acetyl cysteine, reduced overall ROS, cellular levels of hydrogen peroxide, and the growth inhibitory effect of rapamycin. These findings indicate that rapamycin-induced cytostatic effect is characterized by generation of ROS, specifically hydrogen peroxide. This is likely due to the increased levels of MnSOD. By understanding the key signaling molecules in the anti-proliferative effects of rapamycin, we may be able to identify additional predictive markers to improve the therapeutic value of mTOR inhibitors, or study drug combinations that will enhance the effect of ROS-induced cytotoxicity.

Citation Information: Cancer Res 2009;69(23 Suppl):C55.
Abstract C59: Human papillomavirus genotype distribution in northern India: Implications for vaccination
Authors: Patro A. Raj Kumar , Dar Lalit , Bhatla Neerja , Gulati Arti , Kriplani Alka , Pati Sunil Kumar , Kumar Pankaj , Broor Shobha
Published: May 2012

Background: Cervical cancer caused by human papilloma virus (HPV), is the commonest cancer in Indian women, with an estimated 132000 new cases and 76000 deaths annually. More than 100 HPV genotypes have been identified in humans of which at least 40 HPV types are found in the genital tract. Several high-risk HPV types are known to cause the disease. There are only limited data available on the genotype distributions in this region.

Methods: During the period three different cross-sectional studies were carried out: (1) a hospital-based cross-sectional study in which 106 women presenting with invasive cervical cancer; (2) a hospital-based cross-sectional study in which 524 women presenting to have an unhealthy cervix were invited to participate; (3) a community-based cross-sectional study in which 465 women also underwent HPV testing. HPV typing in these studies was done by using L1 consensus PCR followed by reverse line blot hybridization assay (Roche).

Results: In the hospital-based population, among 106 invasive cervical cancers the six commonest HPV types were HPV-16, -18, -45, -59, -33 and 73. HPV-16/18, singly or in combination, were seen in 83% of cases. (2) In the hospital-based population, among the 524 symptomatic hospital subjects, the overall HPV prevalence was 15.5 % and the six commonest HPV types were as follows: HPV -16, -89, -39, -52, -33 and 18. Among the HPV positive women accounted for HPV-16/18 were associated with 34.3%, 45.4% and 65.7% of normal, low-grade and high-grade disease respectively. Among (3) the community-based women, the overall HPV prevalence was 7 % and the six commonest HPV types were as follows: HPV- 16, - 45, -52, -31, -66, and -18.

Conclusions: A wide spectrum of HPV types is seen in north Indian women, with HPV-16/18 are the commonest types in all populations. However, thereafter there is considerable variation. It is estimated that the HPV -16/18 vaccine would reduce over 75% of the total cancer burden in this region. The community population is from a confined geographical area whereas the hospital population includes not only residents of Delhi and neighbouring areas but also further states of North India as well as neighboring countries of Nepal and Bangladesh. Thus more studies are required to establish the true picture of HPV type-distribution in this large and diverse region.

Citation Information: Cancer Res 2009;69(23 Suppl):C59.
Abstract C62: Targeting cancer cell migration and invasion by immunomodulation of actin binding proteins using single domain antibodies (nanobodies)
Authors: De Ganck Ariane , Delanote Veerle , Van den Abbeele Anske , De Clercq Sarah , Vandekerckhove Joël , Gettemans Jan
Published: May 2012

Enhanced motility of cancer cells by remodeling of the actin cytoskeleton through the concerted actions of different classes of actin binding proteins is crucial in the process of cancer cell invasion and metastasis. It is therefore not surprising that expression of quite a few actin associated proteins like gelsolin, myopodin and plastin, fluctuates during tumorigenesis. Furthermore, many studies using overexpression or RNA interference showed a direct involvement of these structural proteins in malignant cell behavior.

Specific inhibitors of most cytoskeletal proteins are lacking. In an attempt to fill this gap, we developed Camelid single domain antibodies (nanobodies or VHHs) against several actin binding proteins including myopodin, gelsolin, and L-plastin. Recombinant nanobodies were used for the biophysical and biochemical characterization of their properties. Furthermore, we used intracellular expression of these nanobodies as intrabodies to develop functional protein domain ‘knock-outs’ to answer the question how ablation of a biochemical property of a protein translates into changes in cell morphology and cell behavior.

Results on gelsolin and L-plastin nanobodies show that they can bind their target antigen with nanomolar affinity in vitro. Cellular assays (for instance a mitochondrial outer membrane recruitment assay) were further used to confirm the interaction between the VHH intrabody and the endogenous antigen in vivo. Epitope mapping revealed for each nanobody to which domain of the protein they bind, demonstrating their selective interaction with different (conformational) epitopes.

In this way we isolated a gelsolin nanobody that only recognizes the activated, calcium-bound conformation of gelsolin. In contrast, other gelsolin nanobodies bind to gelsolin both in the presence and absence of calcium. Functional actin binding assays led to the identification of a gelsolin nanobody that blocks actin monomer binding. Furthermore, this nanobody is also able to reduce the motility of MDA-MB231 breast cancer cells.

A nanobody that specifically interacts with the tandem actin binding domains in L-plastin inhibits actin bundling in vitro. This ‘knock-out’ nanobody inhibits filopodia formation, motility and invasion when expressed in PC-3 prostate cancer cells. Remarkably, L-plastin RNA interference (RNAi) showed no significant effect on filopodial integrity.

In conclusion, single domain VHHs represent a potent tool to ablate protein function and to explore the cellular role of distinct biochemical activities of polypeptides without manipulating gene expression. Furthermore, they can evolve into new therapeutics for cancer treatment targeting currently ‘undruggable’ proteins.

Citation Information: Cancer Res 2009;69(23 Suppl):C62.
Abstract C66: A novel technique to quantify condensation/decondensation status in the nuclear subdomains by QD-FRET
Authors: Shaheen Sharif Mohammad , Akita Hidetaka , Yamashita Atsushi , Katoono Ryo , Yui Nobuhiko , Biju Vasudevanpillai , Ishikawa Mitsuru , Harashima Hideyoshi
Published: May 2012

Recent studies have reported that control of nuclear decondensation at specific nuclear subdomains (i.e. euchromatin) is highly desired for the efficient transfection efficiency. Here, we have established a novel technology for the imaging of nuclear condensation/decondensation status in the nuclear subdomains (i.e. heterochromatin and euchromatin) by based on the three key technologies.

One is imaging of fluorescence resonance energy transfer (FRET) between quantum dots (QDs)-labeled plasmid DNA (pDNA) as a donor, and acceptor-labeled polycation, which can monitor a specific molecular interactions at the nanometre scale.

The second technology is a multilayered lipid envelope-type nanoparticle, which we refer to as a Tetra-lamellar Multi-functional Envelope-type Nano Device (T-MEND). The critical structural elements of the T-MEND are a DNA—polycation condensed core coated with two nuclear membrane-fusogenic inner envelopes and two endosome-fusogenic outer envelopes, which are designed for nuclear delivery via a stepwise fusion. It is required to evaluate the nuclear dispositions in relation to the transgene expression, to avoid a situation that intracellular trafficking processes rate-limit transfection activity.

The last one is confocal image-assisted 3-dimensionally integrated quantification (CIDIQ) method. In this method, fluorophore-labeled pDNA was transfected in HeLa cell line, and then intracellular distribution was distinguished by staining organelle. Z-series of confocal images were captured by confocal laser scanning microscopy (CLSM), and thereafter, pDNA was quantified based on the pixel area of the signals derived from the fluorophore on pDNA in nuclear subdomains (heterochromatin and euchromatin).

As a model of the analysis, QD-labeled DNA was condensed with reductive environment-dependently cleavable polyrotaxane (DMAE-ss-PRX), an artificial condenser, and encapsulated in T-MEND. As a result, transfection activity depends on the number of cationic DMAE of cyclodextrin (α-CD), in conjunction with a drastic change in decondensation efficiency in euchromatin region. These data collectively indicate that this imaging technology is highly advantageous to clarify the dynamics of plasmid DNA in post-nuclear delivery process of cancer cells.

Citation Information: Cancer Res 2009;69(23 Suppl):C66.
Abstract C70: Rapid viscosity-based diagnostic for hyperviscosity in leukemia patients
Authors: van Nimwegen Lena , Hurth Cedric , Zenhausern Frederic
Published: May 2012

The rapid viscosity-based diagnostic test is designed to determine a method by which whole blood viscosity can be clinically tested, in a manner that is both time and cost effective. Leukemia, as well as other blood cell diseases such as Waldenstrom's macroglobulinemia, is associated with hyperviscosity, due to an increase in particular components of blood. Our goal is to use high speed video imaging to characterize the rheological properties of a whole blood sample in order to qualitatively determine the viscosity of the sample. Previous reports used rapid video imaging to describe the mechanics of fluid flow upon impact by a solid sphere (C. Duez et al, Nature Physics 2007, 3, 180–183). The primary method of characterization relies upon the determination of a threshold impact velocity at which the resulting splash profile transitions from a blob to a jet. We performed preliminary tests using a series of glycerol dilutions to mimic potential differences in blood viscosity. Glass beads (2mm diameter) were dropped with a variety of impact velocities into the glycerol solutions. The impact and the resulting splash were recorded using a high-speed camera (Olympus iSPEED 2) at 8000 frames per second. These tests indicated that different viscosities result in different threshold velocities at which the jet splash profile becomes apparent. We are reporting different methods of enrichment of whole blood in order to induce controlled changes in the viscosity of the samples that mimic physiological processes. We have adapted existing methods for enrichment of red blood cell membranes with cholesterol to create a condition known as “spur” red cells which is known to cause a decrease in red cell deformability, altering the visco-elastic properties of the cell (M. Shinitzky, FEBS Letters, 85, 317–320). The splash diagnostic test will be applied to these samples to determine the changes in viscosity resulting from the enrichment. Ultimately, we will test blood samples from leukemia patients at different stages of treatment to further improve the ability of the splash test to be used in a clinical environment.

Citation Information: Cancer Res 2009;69(23 Suppl):C70.
Abstract C72: A mechanistic link between whole-chromosome aneuploidy and DNA damage
Authors: Crasta Karen , Nezi Luigi , Hennessy Morgan , Cameron Lisa , Pan Yunfeng , Chowdhury Dipanjan , Pellman David
Published: May 2012

Cancer is associated with aneuploidy— both structural defects in chromosomes and abnormal numbers of intact chromosomes. The contribution of chromosome breaks to tumorigenesis is well accepted because of the possibility of generating cancer-causing mutations. However, the role of alterations of intact chromosome numbers remains a subject of debate, principally because mechanisms by which whole chromosome aneuploidy would affect cancer pathogenesis are poorly understood. We now have evidence to support one mechanism by which whole chromosome aneuploidy can lead to DNA breaks, via mis-segregation of chromosomes into micronuclei, structures commonly observed in cancer cells. Micronuclei containing intact chromosomes can form after mitotic errors, when the nuclear envelope reforms around a lagging chromosome. We have developed procedures to monitor the fate of micronuclei. Strikingly, whole chromosome-containing micronuclei develop evidence of DNA breaks during the first S phase after they are formed. Blocking DNA replication blocks the formation of these breaks. Defective DNA replication may be due to defective nucleocytoplasmic transport because micronuclei display a marked defect in assembling nuclear pore complexes. These findings suggest one mechanism by which mitotic errors result in DNA damage and thus potentially promote tumorigenesis.

Citation Information: Cancer Res 2009;69(23 Suppl):C72.
Abstract IA-10: Examining the scale and scope of tools and programs to navigate in translational oncology space: Lessons learned
Authors: Friend Stephen H.
Published: May 2012

Over the past five years extensive coherent data has been assembled into probabilistic causal models of diseases. These models show the potential power of generating larger and more comprehensive models. Leveraging significant datasets generated by the Genetics group at Rosetta, the compute clusters, and know-how, we have launched a non-profit commons called Sage based at the Fred Hutchinson Cancer Research Center. We will work to generate 1) a repository of coherent global datasets with genetic information, intermediate markers, and clinical outcomes capable of generating probabilistic causal models of disease, 2) the tools and architecture required to combine data sets and the interoperability required for use of multiple tools, 3) the hosting and curation of diverse disease models as generated by the community and 4) the governance and rules required for this to become a “commons” where open access enables a contributor network. New directions and examples of these models will be discussed.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-10.
Abstract IA-11: Discovery and preclinical activity of IPI-926, a Hedgehog pathway inhibitor
Authors: Adams Julian
Published: May 2012

Malignant activation of the Hedgehog (Hh) pathway plays a key role in multiple types of human tumors, supporting the development of Hedgehog pathway antagonists as therapeutics for cancer. This pathway involves two cell-membrane proteins, Patched (Ptc) and Smoothened (Smo), and is regulated by the absence or presence of Hh ligand. Smo can promote growth of certain cancers via three modes of malignant activation of the Hh pathway: ligand-dependent signaling either to the tumor cell itself or from the tumor to its microenvironment, and ligand-independent signaling activated by genetic mutation. Smo has a critical role in the malignant activation of the Hh pathway because it initiates a signal transduction cascade that can result in cell differentiation, migration, and proliferation. Cyclopamine, a plant Veratrum alkaloid, is a natural product antagonist of the Hh pathway. Efforts to improve the pharmaceutical properties and potency of cyclopamine led to the discovery of IPI-926, a novel semi-synthetic analogue that inhibits the Hh pathway by binding to Smo. IPI-926 demonstrates excellent oral bioavailability, a long plasma half-life and duration of action, and is highly distributed to tumor tissue. Daily oral administration of IPI-926 results in dose-dependent inhibition of tumor growth in multiple preclinical models of cancer. Following tumor debulking in a primary human xenograft SCLC model with a chemotherapy treatment regimen similar to that used clinically in patients with SCLC, once-daily oral administration of IPI-926 leads to a statistically significant delay in tumor regrowth. In certain cancers including pancreatic and ovarian cancer, the tumor cells produce Hh ligand that diffuses out to the surrounding stroma and binds Ptc, resulting in Smo-mediated Hh pathway activation. This paracrine mode of Hh activation leads to recruitment, growth, and maintenance of the stromal tissue in the tumor microenvironment that supports tumor growth. In a genetically engineered murine model of pancreatic cancer, IPI-926 treatment results in depletion of tumor-associated stroma and prolonged survival when given in combination with gemcitabine. Because Smo plays a critical role in malignant activation of the Hh pathway in both the tumor and the stromal microenvironment, Smo may be a target for the management of a broad range of cancers. IPI-926 is currently being investigated in a Phase 1 clinical trial.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-11.
Abstract IA-15: Balancing quiescence and proliferation in stem cells and its implications for cancer
Authors: Fuchs Elaine V.
Published: May 2012

Even though many adult tissues undergo relatively infrequent turnover, they still require stem cells (SCs) which are then used sparingly to replenish cells during normal homeostasis. Moreover, in response to injury, adult SCs must be mobilized quickly to repair damaged tissue. How SCs balance their ability to rest during periods of quiescence, activate to replenish cells and tissue when needed and replace the SCs used for tissue maintenance and repair are fascinating topics in stem cell biology and tissue morphogenesis. Moreover, increasing evidence suggests that the regulatory circuitry governing this balancing act is at the root of some types of tumors both in mice and in humans.

The skin is an excellent model system to understand how undifferentiated SCs self-renew to generate the epidermis and its notable appendages, hair follicles (HFs). In the embryo, skin begins as a single layer of multipotent progenitors, which adhere to each other as well as to an underlying basement membrane rich in extracellular matrix. These progenitors express members of the Lef1/Tcf family of DNA binding proteins thought to act as bipartite transcription factors in association with β-catenin. Excess β-catenin not utilized in intercellular junctions is stabilized when skin progenitors receive Wnt signals from their microenvironment to initiate HF formation. As development proceeds, progenitors respond to additional signals as the skin epithelial tissues mature and differentiate. Postnatally, epidermis retains SCs to undergo homeostasis and maintain the body surface barrier, while HFs undergo cyclical bouts of Wnt signaling that leads to follicle regeneration and hair growth, followed by destruction of the follicle and a resting period to accumulate a new threshold level of signal. The role of Wnt signaling in follicle SC activation and hair regeneration is particularly interesting, as mounting evidence suggests that Wnt signaling may play a general role in governing SC biology and injury repair.

Using skin as our paradigm, we have continued to dissect how extrinsic signaling to SCs sets off a cascade of changes in transcription that govern the activation of SCs during tissue development, homeostasis and hair cycling. We've focused our efforts on the roles of three Tcf/Lef1 family members, all expressed initially in the single-layered epithelium, but which then diversify to be differentially expressed in adult skin SCs and rapidly dividing but committed progeny. Our findings point to Wnt-independent as well as Wnt-dependent functions for these transcription factors, which are likely to be important for our understanding of why Wnt signaling is deregulated in a variety of different human cancers and how Wnt circuitry balances quiescence and proliferation in stem cell and progenitor compartments.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-15.
Abstract IA-16: Control of growth by mTOR signaling
Authors: Sabatini David M.
Published: May 2012

mTOR is the target of the immunosuppressive drug rapamycin and the central component of a nutrient- and hormone-sensitive signaling pathway that regulates cell growth and proliferation. We now appreciate that this pathway becomes deregulated in many human cancers. We have identified two distinct mTOR-containing proteins complexes, one of which regulates growth through S6K and another that regulates cell survival through Akt. These complexes, mTORC1 and mTORC2, define both rapamycin-sensitive and insensitive branches of the mTOR pathway. I will discuss new results from our lab on the regulation of the mTORC1 and mTORC2 pathways. I will provide an overview of mTOR signaling as well as discuss the regulation of mTORC1 by insulin and nutrients and the role of mTORC2 in cancer. We have recently identified new upstream components of the mTORC1 pathway that are involved in amino acid sensing and are starting to understand some of the molecular mechanisms involved in this process. Current evidence suggests that amino acids regulate the mTORC1 pathway by controlling the intracellular localization of mTORC1. Specifically, amino acids promote the movement of mTORC1 to a part of the endomembrane system that also contains its activator Rheb. Amino acids signal through the conserved Rag family of small GTPases that directly interact with the raptor component of mTORC1 in fashion that depends on the GTP-loaded status of the Rags. In addition, I will present evidence that inhibition of mTORC1 by the novel mTOR-interacting protein Deptor is a mechanism for hyperactivating PI3K signaling in multiple myeloma.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-16.
Abstract IA-17: The roles of prolyl hydroxylases in metabolism and cancer
Authors: Gottlieb Eyal
Published: May 2012

Both succinate dehydrogenase (SDH) and fumarate hydratase (FH) are Krebs cycle enzymes that convert succinate to fumarate and fumarate to malate, respectively. SDH is also a functional member (complex II) of the Electron Transport Chain. Surprisingly, although SDH and FH are ‘housekeeping genes’ with key bioenergetic roles, germline mutations in these genes cause cancer. We demonstrated that succinate, a Krebs cycle metabolite (an SDH substrate), functions as an intracellular messenger between mitochondria and the cytosol. Succinate, which accumulates in mitochondria due to the inactivation of SDH, leaks out to the cytosol, where it inhibits the enzymatic machinery of oxygen sensing, mediated by a family of α-ketoglutarate-dependent Prolyl Hydroxylase enzymes (PHD). PHD inhibition by succinate triggers the accumulation and activation of the hypoxia inducible factor (HIF) in the nucleus and the pseudohypoxic response that enhances tumour vascularisation and glycolysis. These and other independent studies collectively suggested that PHD inhibition and pseudohypoxia are important factors that link mitochondrial tumour suppressors and cancer. This observation received further support recently from the fact that PHD2 was genetically identified as a tumour suppressor.

The inhibition of PHD by succinate is achieved by a product inhibition mechanism, given that PHD hydroxylates its targets while utilizing α-ketoglutarate as a substrate and producing succinate. We further characterized the nature of succinate-mediated inhibition of PHD and showed that this inhibition is competitive in nature. Therefore, the ratio, rather than the absolute concentrations, of α-ketoglutarate to succinate or fumarate in cells critically affect PHD activity and HIF activity. We designed and synthesised cell-permeating α-ketoglutarate esters that are hydrolyzed in the cytosol by esterases. These compounds support PHD activity thereby lowering HIF levels and activity in SDH deficient cells. Furthermore, we also demonstrated that α-ketoglutarate increased the affinity of PHD to oxygen and reactivate PHD in cells under hypoxia, resulting in destabilization of the HIFα proteins. It is likely that the binding of α-ketoglutarate by PHD ‘primes’ the enzyme for the binding of oxygen. Our study suggests that well-designed α-ketoglutarate derivatives may have therapeutic potential in the treatment of tumors with functional down-regulation of oxidative phosphorylation. Furthermore, the functional consequences of the observations that PHDs are sensors for oxygen and α-ketoglutarate will be discussed.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-17.
Abstract IA-19: Deconstructing metastasis
Authors: Massagué Joan
Published: May 2012

Metastasis is a multi-stage process that selects for circulating cancer cells that can infiltrate, survive in, and colonize distant organs. The cellular origin, oncogenic alterations, tissue affinities, and circulation patterns of tumors markedly influence the sites and temporal course of metastasis. Cancer cell dissemination may be followed by a protracted period of latency before relapse in one or more organs, as in breast cancer, or by a swift colonization of multiple organs, as in lung adenocarcinoma. We have sought to incorporate this varied biology into experimental models to deconstruct metastasis. Searching for mechanisms that prime breast cancer cells for infiltration of different organs, we found few requirements for cancer cell extravasation through fenestrated bone marrow capillaries, certain key requirements (EGFR ligands, COX2, TGFβ-induced angiopoietin-like 4) for infiltration through the non-fenestrated walls of lung and brain capillaries, and additional mediators (sialyl transferase ST6GalNac5) for infiltration though brain capillaries with blood-brain barrier. Searching for mechanisms that allow infiltrated breast cancer cells to survive as latent disease, we found that a hyperactive SRC pathway supports the responsiveness of breast cancer cells to certain survival factors in the marrow microenvironment. Searching for mechanisms that in contrast underlie the rapid metastasis of lung adenocarcinomas to brain and bone, we uncovered an involvement of WNT/TCF signaling through HOXH9 and LEF1. These striking disparities in the natural progression of different cancers bring into focus important questions about the evolution of metastatic traits, the molecular mediators involved, and the treatment opportunities for the prevention of metastasis.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-19.
Abstract IA-2: PI3-Kinase and cancer metabolism
Authors: Cantley Lewis C.
Published: May 2012

Mutations in Phosphoinositide 3-Kinase (PI3K) are among the most common events in solid tumors. Recent studies have revealed a highly conserved pathway by which PI3K regulates cell growth and glucose metabolism. Mice with activating mutations in the PIK3CA gene develop cancers that have high rates of glucose uptake and metabolism and pharmacological inhibitors of PI3K block glucose uptake and cause tumor shrinkage. We have also shown that the embryonic form of pyruvate kinase plays a critical role in tumor cell growth by diverting glucose metabolites into anabolic processes. The biochemical basis for these observations and their importance for tumor growth will be discussed.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-2.
Abstract IA-20: EMT in tumor invasion and metastasis
Authors: Brabletz Thomas
Published: May 2012

Most colorectal adenocarcinomas (CRC) have mutations in the APC gene leading to overexpression of the Wnt-pathway effector β-catenin. By acting as a transcriptional activator, nuclear β-catenin is involved in two fundamental processes in embryonic development: epithelial to mesenchymal transition (EMT) and generation of stem cells.

We have previously shown, that in particular tumor cells at the invasive front of CRCs accumulate nuclear β-catenin, undergo an EMT and aberrantly express EMT-associated transcriptional repressors, like ZEB1. The amount of such cells strongly correlates with clinical outcome and metastasis formation.

We further showed that ZEB1 represses target genes involved in basement membrane formation and epithelial cell polarity. Moreover we report that ZEB1 directly suppresses transcription of members of the miRNA-200 family, which strongly activate epithelial differentiation in pancreatic, colorectal and breast cancer cells. Notably, the EMT-activators TGFβ2 and ZEB1 itself are predominant targets downregulated by these miRNAs. These results indicate that ZEB1 triggers a microRNA-mediated positive feedbackloop, which stabilizes EMT and promotes invasion of cancer cells. In contrast tumor cells in central tumor areas are differentiated and often show membranous, E-cadherin-bound β-catenin.

Strikingly, metastases show again a differentiated phenotype and lack nuclear beta-catenin, indicating a mesenchymo-epithelial re-transition (MET) and a regulatory role of the tumor environment during malignant tumor progression.

Based on the developmental functions of beta-catenin and our data we propose, that the EMT-associated tumor cells at the invasive front act as “migrating cancer stem cells” which can re-differentiate and, depending on the range of dissemination, give raise to the primary carcinoma and metastases. We suggest that both primary tumors and metastases are derived from a pool of EMT-associated “migrating cancer stem cells” at the tumor host interface. They are defined by strong nuclear beta-catenin accumulation and EMT-phenotype, which gives these epithelial tumor cells a feature driving malignant tumor progression including metastasis: the unusual combination of a migratory and stem cell phenotype.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-20.
Abstract IA-4: Studying tumor evolution in mouse models of cancer
Authors: Jacks Tyler
Published: May 2012

Like other solid tumors, lung adenocarcinoma progresses through multiple stages including tumor initiation, expansion in the lung, and metastasis of the primary tumor to distant organs. Dissection of this process requires quantitative and tractable models that recapitulate the human disease at the genetic and histological level. We have employed autochthonous mouse models of lung adenocarcinoma that recapitulate tumor initiation, progression and metastasis in the human disease both genetically, and pathologically. We have established oncogenic Kras as the initiating event in lung adenoma and amplification of the oncogenic signaling is associated with progression to adenocarcinoma. The p53 tumor suppressor limits tumor progression in this model. Restoration of the Trp53 locus has pinpointed the adenoma-adenocarcinoma transition as the stage in which p53 function is critical for tumor suppression. Expression of oncogenic Kras in the absence of p53 leads to the development of distant metastases after long latency. This suggests that unknown cooperating genetic events are required for metastatic spread and we are utilizing multiple tools to identify these changes. Use of lentiviral vectors that drive stable GFP expression in tumors allows for identification and purification of tumor cells. Additionally, identification of the lentiviral integration site in each tumor allows the clonal relationship between metastases and the primary tumors to be unequivocally established. Gene expression and DNA copy number analyses of metastasis-derived cell lines and primary lung tumors have uncovered a metastasis associated gene expression signature and recurrent genomic alterations. Integration of these datasets, other genome-wide analyses and human tumor data are providing insights into the molecular mechanism and biology of lung cancer progression and metastasis.

Citation Information: Cancer Res 2009;69(23 Suppl):IA-4.
Expression of Cocaine- and Amphetamine-Regulated Transcript Is Associated with Worse Survival in Small Bowel Carcinoid Tumors
Authors: Landerholm Kalle , Shcherbina Liliya , Falkmer Sture E. , Järhult Johannes , Wierup Nils
Published: May 2012

Purpose: Cocaine- and amphetamine-regulated transcript (CART) peptide exerts several regulatory functions acting both as neurotransmitter and hormone. We recently showed that CART is expressed in various neuroendocrine tumors, including small bowel carcinoids. The main objective of the present study was to examine whether CART expression is associated with survival in patients with small bowel carcinoid. Secondary aims were to assess whether CART expression is associated with other tumor characteristics or clinical symptoms.

Experimental Design: Specimens from 97 patients with small bowel carcinoids were examined for CART expression using immunohistochemistry. A CART score was introduced on the basis of the proportion of CART immunoreactive cells. On inclusion, specimens were examined by routine histopathologic methods and detailed clinical patient data were retrieved. The effect of CART on cell viability was assessed in vitro using two intestinal tumor cell lines.

Results: Expression of CART (P = 0.011) and increasing CART score (P = 0.033) were associated with worse disease-specific survival. Adjusting for age, disease stage, and tumor grade in multivariable analysis, CART expression was still associated with worse survival [Low CART HR, 5.47; 95% confidence interval (CI), 0.71–42.46; and High CART HR, 9.44; 95% CI, 1.14–78.14]. CART expression was not associated with patient age, disease stage, tumor grade, or any presenting symptom. Supporting our clinical data, we found that CART promoted tumor cell viability in vitro in two different tumor cell lines.

Conclusion: Expression of CART in small bowel carcinoid tumors is associated with worse survival. Clin Cancer Res; 18(13); 3668–76. ©2012 AACR.
BEAMing Up Personalized Medicine: Mutation Detection in Blood
Authors: Richardson Andrea L. , Iglehart J. Dirk
Published: May 2012

BEAMing is a feasible, accurate, and sensitive method for detection of PIK3CA mutations in circulating tumor DNA in blood. Mutation status of PIK3CA may change between primary tumor and recurrence. The results suggest a new approach for noninvasive determination of current mutation status in patients with metastatic disease. Clin Cancer Res; 18(12); 3209–11. ©2012 AACR.
Smoothened Antagonists Reverse Taxane Resistance in Ovarian Cancer
Authors: Steg Adam D. , Katre Ashwini A. , Bevis Kerri S. , Ziebarth Angela , Dobbin Zachary C. , Shah Monjri M. , Alvarez Ronald D. , Landen Charles N.
Published: May 2012

The hedgehog pathway has been implicated in the formation and maintenance of a variety of malignancies, including ovarian cancer; however, it is unknown whether hedgehog signaling is involved in ovarian cancer chemoresistance. The goal of this study was to determine the effects of antagonizing the hedgehog receptor, Smoothened (Smo), on chemotherapy response in ovarian cancer. Expression of hedgehog pathway members was assessed in three pairs of parental and chemotherapy-resistant ovarian cancer cell lines (A2780ip2/A2780cp20, SKOV3ip1/SKOV3TRip2, HeyA8/HeyA8MDR) using quantitative PCR and Western blot analysis. Cell lines were exposed to increasing concentrations of two different Smo antagonists (cyclopamine, LDE225) alone and in combination with carboplatin or paclitaxel. Selective knockdown of Smo, Gli1, or Gli2 was achieved using siRNA constructs. Cell viability was assessed by MTT assay. A2780cp20 and SKOV3TRip2 orthotopic xenografts were treated with vehicle, LDE225, paclitaxel, or combination therapy. Chemoresistant cell lines showed higher expression (>2-fold, P < 0.05) of hedgehog signaling components compared with their respective parental lines. Smo antagonists sensitized chemotherapy-resistant cell lines to paclitaxel, but not to carboplatin. LDE225 treatment also increased sensitivity of ALDH-positive cells to paclitaxel. A2780cp20 and SKOV3TRip2 xenografts treated with combined LDE225 and paclitaxel had significantly less tumor burden than those treated with vehicle or either agent alone. Increased taxane sensitivity seems to be mediated by a decrease in P-glycoprotein (MDR1) expression. Selective knockdown of Smo, Gli1, or Gli2 all increased taxane sensitivity. Smo antagonists reverse taxane resistance in chemoresistant ovarian cancer models, suggesting combined anti-hedgehog and chemotherapies could provide a useful therapeutic strategy for ovarian cancer. Mol Cancer Ther; 11(7); 1587–97. ©2012 AACR.
Betulinic Acid Targets YY1 and ErbB2 through Cannabinoid Receptor-Dependent Disruption of MicroRNA-27a:ZBTB10 in Breast Cancer
Authors: Liu Xinyi , Jutooru Indira , Lei Ping , Kim KyoungHyun , Lee Syng-ook , Brents Lisa K. , Prather Paul L. , Safe Stephen
Published: May 2012

Treatment of ErbB2-overexpressing BT474 and MDA-MB-453 breast cancer cells with 1 to 10 μmol/L betulinic acid inhibited cell growth, induced apoptosis, downregulated specificity protein (Sp) transcription factors Sp1, Sp3, and Sp4, and decreased expression of ErbB2. Individual or combined knockdown of Sp1, Sp3, Sp4 by RNA interference also decreased expression of ErbB2 and this response was because of repression of YY1, an Sp-regulated gene. Betulinic acid–dependent repression of Sp1, Sp3, Sp4, and Sp-regulated genes was due, in part, to induction of the Sp repressor ZBTB10 and downregulation of microRNA-27a (miR-27a), which constitutively inhibits ZBTB10 expression, and we show for the first time that the effects of betulinic acid on the miR-27a:ZBTB10-Sp transcription factor axis were cannabinoid 1 (CB1) and CB2 receptor–dependent, thus identifying a new cellular target for this anticancer agent. Mol Cancer Ther; 11(7); 1421–31. ©2012 AACR.
IEX-1 Deficiency Protects against Colonic Cancer
Authors: Ustyugova Irina V. , Zhi Liang , Abramowitz Joel , Birnbaumer Lutz , Wu Mei X.
Published: May 2012

The immediate early response gene X-1 (IEX-1) is involved in regulation of various cellular processes including proliferation, apoptosis in part by controlling homeostasis of reactive oxygen species (ROS) at mitochondria. The present study shows reduced inflammatory responses and colorectal cancer in IEX-1 knockout (KO) mice treated with azoxymethane/dextran sulfate sodium (DSS). However, DSS induced worse colitis in RAG−/−IEX-1−/− double KO mice than in RAG and IEX-1 single KO mice, underscoring an importance of T cells in IEX-1 deficiency-induced protection against colon inflammation. Lack of IEX-1 promoted the differentiation of interleukin (IL)-17–producing T cells, concomitant with upregulation of Gαi2 expression, a gene that is well-documented for its role in the control of inflammation in the colon. In accordance with this, T-helper 17 (TH17) cell differentiation was compromised in the absence of Gαi2, and deletion of Gαi2 in T cells alone aggravated colon inflammation and colorectal cancer development after azoxymethane/DSS treatment. Null mutation of IEX-1 also enhanced both proliferation and apoptosis of intestinal epithelial cells (IEC) after injury. A potential impact of this altered IEC turnover on colon inflammation and cancer development is discussed. These observations provide a linkage of IEX-1 and Gαi2 expression in the regulation of TH17 cell differentiation and suggest a previously unappreciated role for IEX-1 in the control of colon epithelial homeostasis. Mol Cancer Res; 10(6); 760–7. ©2012 AACR.
Abstract A100: Histological classification of primary lung cancer in relation to age, gender, and types of tobacco smoking.
Authors: Bukhari Mulazim , Hussain Muhammad , Naeem Samina
Published: May 2012

A100

Background

According to available data the lung cancer remains the leading malignancy amongst males showing a strongest association with smoking. The study was conducted to analyze the histological classification of primary lung cancer in relation to age, gender and types of Tobacco Smoking

Methods

The study was conducted on randomly selected 300 patients of 10-90 years age from Ghulab Devi Chest Hospital Lahore. Light microscopy was used for histopathological classification on the sections stained with haematoxylin and eosin. Special (PAS and Alcian blue) stains were used for subclassication. Literature for WHO classification was reviewed.

Results

The primary malignancy of lung was more common in males (male to female ratio was 5.7:1) and in old ages with mean age was 54.17±3.46 years.. Significantly large numbers of patients (70%) were smokers. The trend of smoking is changing in Pakistan from old traditional hukka to cigarette. A strong association of smoking was found between small cell carcinoma (SCC), and squamous cell carcinoma (SQCC), and Large cell carcinoma (LCC), (P<0.02, P< 0.001 and p<0.02 respectively). No significant difference was seen between smokers and non smokers harboring adenocarcinoma (ADC;P>0.05). According to the WHO classification, SQCC (43%) was found to be the commonest histological variant and SCC (22%) was second in the frequency. The frequency of ADC, LCC and others variants was 18%, 11%and 5% respectively.

Conclusion

WHO criteria are the better ways to classify the lung carcinoma with light microscopy and provide a potential widespread and worldwide application of this classification system. A strong association of lung cancer was found with age, sex, and all types of smoking and histological variants.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):A100.
Abstract A102: Men with low serum cholesterol have a lower risk of high-grade prostate cancer in the Prostate Cancer Prevention Trial
Authors: Platz Elizabeth , Till Cathee , Goodman Phyllis , Parnes Howard , Figgs William , Albanes Demetrius , Kristal Alan
Published: May 2012

A102

Objectives

Several prospective studies suggest that use of cholesterol-lowering statin drugs is inversely associated with advanced and possibly high-grade prostate cancer. A nested case-control study investigating low circulating cholesterol as a possible mechanism underlying these findings reported that men with a lower cholesterol concentration had a lower risk of high-grade and possibly advanced prostate cancer (Int J Cancer 2008;123:1693-8). Given these findings, we investigated the association of low serum cholesterol with prostate cancer overall and by histologic grade in the Prostate Cancer Prevention Trial (PCPT). Unlike standard cohort studies, men in the PCPT underwent PSA screening annually, cases were biopsy detected, diagnoses and Gleason sum determinations were confirmed centrally, and controls were men who were biopsied at the end of the trial per trial protocol irrespective of indication.

Methods

We conducted a prospective cohort study of 5,616 men aged 55+ years old randomized to the placebo arm of the PCPT between 1993 and 1996 and who had serum cholesterol measured at entry. By the end of follow-up, 1,251 cases were confirmed. Serum cholesterol concentration was measured enzymatically. We used logistic regression to calculate the multivariable odds ratio (OR) of total, organ-confined, and Gleason sum ≥ 8 (n=59), 7 (n=199), and < 7 (n=993) prostate cancer comparing low (normal: < 200 mg/dL) to high (borderline and elevated cholesterol: ≥ 200 mg/dL) serum cholesterol.

Results

Men with low cholesterol had a lower risk of Gleason sum ≥ 8 prostate cancer (OR=0.41, 95% confidence interval (CI) 0.22-0.77; p-trend across quintiles of cholesterol = 0.01) compared with men with high cholesterol; this association was stronger after restricting to organ-confined disease (OR=0.32, 95% CI 0.15-0.66, p-trend < 0.001). No association was present for prostate cancer overall (OR=0.97, 95% CI 0.85-1.11, p-trend=0.43), or Gleason < 7 (OR=1.03, 95% CI 0.89-1.18, p-trend=0.94) or 7 (OR=0.93, 95% CI 0.69-1.24, p-trend=0.49) disease.

Conclusion

These prospective findings from the PCPT, in which the opportunity for detection of high-grade prostate cancer was similar because all men underwent biopsy, suggest that low cholesterol may protect against the development of high-grade prostate cancer. The contemporary body of literature on statins, cholesterol, and prostate cancer suggests that cholesterol metabolism should be investigated further in the etiology of prostate cancer that has a worse prognosis.

Funding: NCI/NIH P01 CA108964 (Biology of the PCPT). The content of this work is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):A102.