Common Human Cancers Research Articles

Novel mutations of PIK3CA gene in head and neck squamous cell carcinoma.

HNSCC is the sixth most common human cancer globally. In Saudi Arabia, HNSCC accounts for seven percent of all newly diagnosed cancer cases. The PIK3CA is one of the most commonly mutated oncogene in human malignancies, including HNSCC. The objective of this study is to identify mutations in exon 9 and exon 20 of the PIK3CA gene among Saudi HNSCC patients, determine the frequency of these mutations and correlate with clinical and pathological findings. Histopathologically confirmed paraffin embedded HNSCC tumor tissues from 48 patients were obtained. Capillary sequencing method was used to sequence exons 9 and 20 of the PIK3CA gene. Concurrently, the expression analysis of the PIK3CA and PTEN genes were performed using real-time PCR. Sixty percent of the samples studied were of pharyngeal cancer. A total of seven mutations were identified in exons 9 and 20 of the PIK3CA gene in 14 HNSCC tumor tissue specimens. The seven mutations encompassed one hot spot mutation E542K, a common mutation T1025T and the five novel mutation comprising three missense and two silent mutations. Interestingly, eight out of the 14 samples with a mutation were of patients with pharyngeal cancer. PIK3CA gene plays a crucial role in carcinogenesis in general and HNSCC in particular. The identification of five novel mutations suggest that Saudis may have different frequencies of somatic genetic alterations that may influence HNSCC compared to other populations.

Detection of Mycobacterium tuberculosis In Urinary Bladder Cancer Tissues By Using Transmission Electron Microscope

Background: Bladder cancer is one of the most common human cancers in Iraq and the world. While smoking, age sex, and occupational exposure to aromatic amines are the most prominent among the risk factors identified, long term Inflammation and chronic infection may largely play some role in urinary bladder cancer (UBC) development. In the present study we worked on urinary bladder cancer and noncancerous Formalin-Fixed Paraffin Embedded (FFPE) Tissue specimens of Iraqi patients, the current study used Acid Fast Stain and Transmission Electron Microscope for detection of Mycobacterium tuberculosis in Urinary Bladder tissues. Objectives: microscopical detection of Mycobacterium tuberculosis in urinary bladder cancer. Methodology: The current study used urinary bladder cancer (UBC) formalin-fixed paraffin embedded tissues (FFPET) specimens of Iraqi patients collected of several privet histopathology labs in AL-Najaf province, the specimens were 50 specimens of UBC patients and 25 different noncancerous pathological bladder specimens. Slides of urinary bladder FFPE tissues were stained with Ziehl-Neelsen (ZN) stain. Examining of slides were conducted using Transmission Electron Microscope (TEM) imaging was performed special procedure was used for TEM slides preparation. Results: FFPE tissues were stained with Ziehl-Neelsen (ZN) stain. Examining of slides showed presence of high number of acid fast bacilli (AFB) in one microscopical field. UBC tissue slides showed the highest percentage comparing to noncancerous patients (76.6% and 23.4%) respectively. For further confirmation and study of ZN stain results, Transmission Electron Microscope (TEM) imaging was performed. The results showed presence ofdifferent morphological shapes of acid fast bacilli cells appeared in TEM fields and most cells were observed attaching to the urothelial cell membrane. Conclusions: high percentage of MTBC and MTB were detected among patients with UBC compared to noncancerous cases. Recommendations: modern techniques should be used for MTBC and MTB detection in laboratories, and further study for the relationship between chronic MTB infection and UBC are required.

Low expression of Aldo-keto reductase 1B10 is a novel independent prognostic indicator for nasopharyngeal carcinoma.

BackgroundNasopharyngeal carcinoma (NPC) is one of the most common human head and neck cancers with high incidence in Southern China, Southeast Asia and North Africa. Because of its nonspecific symptoms, the early diagnosis of NPC is very difficult. The 5-year survival rate is not ideal in spite of great innovations in radiation and chemotherapy treatments. Highly sensitive and specific prognostic biomarkers are eager for NPC clinical diagnosis. To find specific target molecules is very important for individualized treatment. Aldo–keto reductase B10 (AKR1B10) is closely related to tumorigenesis and tumor development, and however, its expression level in NPC tissues is not clear.ResultsAKR1B10 expression levels were validated in benign, para-cancerous nasopharyngeal and NPC tissues by immunohistochemical evaluation. AKR1B10 was positively expressed in 42 (82.4 %) of 51 benign specimens, and 235 (98.7 %) of 238 para-carcinoma specimens. This percentage was significantly higher than 44.5 % (133/299) in nasopharyngeal carcinoma tissue (p < 0.01). AKR1B10 mRNA quantitative levels detected by real-time quantitative RT-PCR in 90 NPC tissue samples (0.10 ± 0.21) were significantly lower than that in 15 benign tissue samples (1.03 ± 1.12) (p < 0.01). AKR1B10 expression levels in NPC were correlated negatively with T-classification, lymph node metastasis (p < 0.05). We established nasopharyngeal cancer monoclonal cells CNE-2/AKR1B10 with AKR1B10 stable expression and CNE-2/vector cells without AKR1B10 expression by using a modified lentivirus-mediated method, and found that AKR1B10 inhibited the proliferation of CNE-2/AKR1B10 cells by using MTT assay and flow cytometry, and cell migration by in vitro scratch test.ConclusionTaken together, our data suggest that low expression of AKR1B10 is an independent prognostic indicator in nasopharyngeal carcinoma, and that AKR1B10 may be involved in regulating the proliferation and migration of nasopharyngeal cancer cells.

Abstract B08: Space radiation exposure induces stable epigenome alterations relevant to human lung cancer

Abstract Manned interplanetary travel is imminent, but currently inhibited by uncertainty surrounding the long-term human health risks associated with space radiation exposure, for which there is currently no effective means of shielding. Terrestrial exposure to ionizing radiation, such as γ- or X-rays, increases the age-related risk of most common human cancers, however the extent to which these risks can be extrapolated to astronauts in deep space remains unclear. Compared to terrestrial radiation, space radiation contains high charge and energy (HZE) ions with a high linear energy transfer (high-LET). As they traverse the cell, HZE ions interact directly with macromolecules along the particle trajectory, and emit high-energy secondary electrons (δ rays) that extend laterally for several microns, resulting in a wide and densely ionizing core track. HZE radiation creates a complex mixture of DNA damage (double strand breaks, single strand breaks, oxidative base damage, etc.) in tight clusters along the particle track that can be difficult to repair. Consequently, research thus far has focused on the influence of both terrestrial and space radiation on DNA. Here we sought to determine the acute impact and long-term consequences of space radiation exposure on the epigenome. Immortalized human bronchial epithelial cells (3KT) were exposed to low LET (X-ray) or HLET radiation (28Si, 56Fe). Cells were harvested after 48hrs or maintained in continuous culture for an additional 3 months, and DNA methylation patterns using the Illumina Human 450K platform. A linear mixed-effects model was applied to identify changes in DNA methylation significantly associated with dose, source, or time after exposure. Significantly, we found that radiation-induced methylation changes occur early and persist over time, reflecting a stable and heritable change to the epigenome. CpG sites affected by high and low LET radiation exposure also tended to affect CpG sites in different genomic compartments. Fe-affected CpG sites were enriched in CpG island ‘shores’ and underrepresented in gene bodies, whereas those affected by X-ray exposure were enriched in gene bodies and intergenic regions. Interestingly, Fe affected sites tended to affect CpG sites in regions with features of ‘open’ chromatin, such as promoters and distal enhancer elements, whereas sites affected by Si were overrepresented in heterochromatic regions. To probe the significance of our findings with respect to human lung cancer, we examined the methylation status of the radiation-sensitive CpG sites in primary human lung cancers analyzed in The Cancer Genome Atlas (TCGA) project. We found that the methylation status of Fe radiation sensitive sites could discriminate tumor from normal tissue for both lung adenocarcinomas and squamous cell lung carcinomas. No such relationship existed for the sites affected by low LET X-rays or 28Si radiation exposure. Thus, the high LET radiation exposure ‘signature’ reflects a cancer-specific methylation pattern observed in human primary lung cancers. From these data, we suggest that the stable imprint of a prior high LET radiation exposure is reflected in the DNA methylation pattern, and may prove useful as a biomarker of long-term, individual cancer risk. Citation Format: E. Kennedy, D.R. Powell, Z. Li, J.S.K. Bell, H. Feng, W. Dynan, B. Dwivedi, J. Kowalski, K.N. Conneely and P.M. Vertino. Space radiation exposure induces stable epigenome alterations relevant to human lung cancer. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Sep 24-27, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2016;76(2 Suppl):Abstract nr B08.

Molecular Classification of Colorectal Cancers and Clinical Application

The molecular genetics of colorectal cancers (CRCs) is among the best understood of common human cancers. It is difficult to predict the prognosis and/or to predict chemoresponding in CRC patients. At present, prognosis is based predominantly on the tumor stage and pathological examination of the disease. Molecular classification of CRCs, based on genomics and transcriptomics, proposed that CRCs can be classified into at least three-to-six subtypes, depending on the gene expression pattern, and groups of marker genes representing to each subtype have also been reported. Gene expression-based subtyping is now widely accepted as a relevant source of disease stratification. We reviewed the previous studies on CRC subtyping, international consortium dedicated to large-scale data sharing and analytics recently established four consensus molecular subtypes with distinguishing features. Predictive markers identified in these studies are under investigation and large-scale clinical evaluations of molecular markers are currently in progress.

Tumor-associated macrophages in the cutaneous SCC microenvironment are heterogeneously activated.

Tumor-associated macrophages (TAMs) may have an important role in tumor immunity. We studied the activation state of TAMs in cutaneous SCC, the second most common human cancer. CD163 was identified as a more abundant, sensitive, and accurate marker of TAMs when compared with CD68. CD163(+) TAMs produced protumoral factors, matrix metalloproteinases 9 and 11 (MMP9 and MMP11), at the gene and protein levels. Gene set enrichment analysis (GSEA) was used to evaluate M1 and M2 macrophage gene sets in the SCC genes and to identify candidate genes in order to phenotypically characterize TAMs. There was coexpression of CD163 and alternatively activated "M2" markers, CD209 and CCL18 (chemokine (C-C motif) ligand 18). There was enrichment for classically activated "M1" genes in SCC, which was confirmed in situ by colocalization of CD163 and phosphorylated STAT1 (signal transducer and activator of transcription 1), IL-23p19, IL-12/IL-23p40, and CD127. Also, a subset of TAMs in SCC was bi-activated as CD163(+) cells expressed markers for both M1 and M2, shown by triple-label immunofluorescence. These data support heterogeneous activation states of TAMs in SCC, and suggest that a dynamic model of macrophage activation would be more useful to characterize TAMs.

The Clinicopathologic Significance of BAF250a (ARID1A) Expression in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common and lethal human cancers. Recently, exome sequencing has revealed that mutation of ARID1A is frequent in HCC. Herein, we determined the clinicopathologic significance of ARID1A expression in HCC. We detected the level of mRNA and protein expression of ARID1A in 12 paired HCC tumors and adjacent non-cancerous tissues by quantitative real-time PCR and immunohistochemistry (IHC). In addition, we determined the expression of BAF250a on 121 HCC tumors by IHC and assessed the association between BAF250a expression and clinicopathologic and prognostic features. The levels of ARID1A mRNA were significantly elevated in 10 of 12 HCC tumors compared with adjacent non-cancerous tissues. The level of BAF250a protein expression was higher in 10 of 12 HCC tumors compared with adjacent liver tissues. IHC indicated that 12.17% of HCC tumors (14/115) were BAF250a-negative. Loss of BAF250a was significantly associated with larger tumor size, but not associated with other clinicopathologic features. There was no significant difference in disease-free or overall survival between BAF250a-positive and BAF250a-negative patients. Most HCCs had an increased level of ARID1A mRNA and BAF250a expression. Loss of BAF250a was significantly more frequent in larger HCC tumors, but had no prognostic significance.

A lincRNA connected to cell mortality and epigenetically-silenced in most common human cancers

Immortality is an essential characteristic of human carcinoma cells. We recently developed an efficient, reproducible method that immortalizes human mammary epithelial cells (HMEC) in the absence of gross genomic changes by targeting 2 critical senescence barriers. Consistent transcriptomic changes associated with immortality were identified using microarray analysis of isogenic normal finite pre-stasis, abnormal finite post-stasis, and immortal HMECs from 4 individuals. A total of 277 genes consistently changed in cells that transitioned from post-stasis to immortal. Gene ontology analysis of affected genes revealed biological processes significantly altered in the immortalization process. These immortalization-associated changes showed striking similarity to the gene expression changes seen in The Cancer Genome Atlas (TCGA) clinical breast cancer data. The most dramatic change in gene expression seen during the immortalization step was the downregulation of an unnamed, incompletely annotated transcript that we called MORT, for mortality, since its expression was closely associated with the mortal, finite lifespan phenotype. We show here that MORT (ZNF667-AS1) is expressed in all normal finite lifespan human cells examined to date and is lost in immortalized HMEC. MORT gene silencing at the mortal/immortal boundary was due to DNA hypermethylation of its CpG island promoter. This epigenetic silencing is also seen in human breast cancer cell lines and in a majority of human breast tumor tissues. The functional importance of DNA hypermethylation in MORT gene silencing is supported by the ability of 5-aza-2′-deoxycytidine to reactivate MORT expression. Analysis of TCGA data revealed deregulation of MORT expression due to DNA hypermethylation in 15 out of the 17 most common human cancers. The epigenetic silencing of MORT in a large majority of the common human cancers suggests a potential fundamental role in cellular immortalization during human carcinogenesis.

Advanced basal cell carcinoma, the hedgehog pathway, and treatment options - role of smoothened inhibitors.

Cutaneous basal cell carcinoma (BCC) is the most common human cancer and its incidence is rising worldwide. Ultraviolet radiation exposure, including tanning bed use, as well as host factors play a role in its development. The majority of cases are treated and cured with local therapies including surgery. Yet, the health care costs of diagnosis and treatment of BCCs in the US is substantial. In the United States, the cost of nonmelanoma skin cancer care in the Medicare population is estimated to be US$426 million per year. While rare, locally advanced BCCs that can no longer be controlled with surgery and/or radiation, and metastatic BCCs do occur and can be associated with significant morbidity and mortality. Vismodegib (GDC-0449), a smoothened inhibitor targeted at the hedgehog pathway, is the first US Food and Drug Association (FDA)-approved agent in the treatment of locally advanced, unresectable, and metastatic BCCs. This class of agents appears to be changing the survival rates in advanced BCC patients, but appropriate patient selection and monitoring are important. Multidisciplinary assessments are essential for the optimal care and management of these patients. For some patients with locally advanced BCC, treatment with a hedgehog inhibitor may eliminate the need for an excessively disfiguring or morbid surgery.

Inhibition of Fatty Acid Synthase Sensitizes Prostate Cancer Cells to Radiotherapy.

Many common human cancers, including colon, prostate and breast cancer, express high levels of fatty acid synthase compared to normal human tissues. This elevated expression is associated with protection against apoptosis, increased metastasis and poor prognosis. Inhibitors of fatty acid synthase, such as the cerulenin synthetic analog C75, decrease prostate cancer cell proliferation, increase apoptosis and decrease tumor growth in experimental models. Although radiotherapy is widely used in the treatment of prostate cancer patients, the risk of damage to neighboring normal organs limits the radiation dose that can be delivered. In this study, we examined the potential of fatty acid synthase inhibition to sensitize prostate cancer cells to radiotherapy. The efficacy of C75 alone or in combination with X irradiation was examined in monolayers and in multicellular tumor spheroids. Treatment with C75 alone decreased clonogenic survival, an effect that was abrogated by the antioxidant. C75 treatment also delayed spheroid growth in a concentration-dependent manner. The radiosensitizing effect of C75 was indicated by combination index values between 0.65 and 0.71 and the reduced surviving fraction of clonogens, in response to 2 Gy X irradiation, from 0.51 to 0.30 and 0.11 in the presence of 25 and 35 μM C75, respectively. This increased sensitivity to radiation was reduced by the presence of the antioxidant. The C75 treatment also enhanced the spheroid growth delay induced by X irradiation in a supra-additive manner. The level of radiation-induced apoptosis in prostate cancer cells was increased further by C75, which induced cell cycle arrest in the G2/M phase, but only at a concentration greater than that required for radiosensitization. Radiation-induced G2/M blockade was not affected by C75 treatment. These results suggest the potential use of fatty acid synthase inhibition to enhance the efficacy of radiotherapy of prostate carcinoma and that C75-dependent cell cycle arrest is not responsible for its radiosensitizing effect.

Dermal Drug Delivery for Cutaneous Malignancies: Literature at a Glance

Purpose Cutaneous malignancies are the most common human cancers, and despite growing public awareness of the harmful effects of sun exposure, incidence and morbidity continue to rise which has generated great interest in unravelling of their aetiology and in the search for new non-invasive treatment strategies.

PiR-55490 inhibits the growth of lung carcinoma by suppressing mTOR signaling.

Lung carcinoma is the most common human cancer with poor prognosis and has an increasing incidence in recent years. However, the related mechanism of lung cancer onset has not been completely explored. Piwi-interacting RNA (piRNA) is a type of noncoding small RNA with established function in germ cells, and interestingly, piRNA has also been shown to be implicated in cancer biology. In this study, piR-55490 was found to be silenced in lung carcinoma specimens and cell lines, compared with normal lung tissues and cells. Intriguingly, the expression level of piR-55490 is negatively associated with patients' survival. Restoration of piR-55490 can reduce the proliferation rates of lung cancer cells, while piR-55490 suppression led to the gain in the proliferation rates. Animal model study showed that piR-55490 can suppress the growth of lung carcinoma xenograft. Further study revealed that piR-55490 suppressed the activation of Akt/mTOR pathway in lung cancer cells. Surprisingly, piR-55490 was found to bind 3'UTR of mTOR messenger RNA (mRNA) and induce its degradation in a mechanism similar to microRNA (miRNA). The introduction of an mTOR construct resistant to action of piR-55490 was able to abolish the effect of piR-55490 on lung cancer cells. In conclusions, we found that piRNA can contribute to the suppression of cancer cell phenotypes by directly targeting a oncogene mRNA. This finding facilitates our understanding of piRNA's function and its association with human cancer.

Ingenol Mebutate Signals via PKC/MEK/ERK in Keratinocytes and Induces Interleukin Decoy Receptors IL1R2 and IL13RA2.

Squamous cell carcinoma (SCC) is the second most common human skin cancer and the second leading cause of skin cancer-related death. Recently, a new compound, ingenol mebutate, was approved for treatment of actinic keratosis, a precursor of SCC. As the mechanism of action is poorly understood, we have further investigated the mechanism of ingenol mebutate-induced cell death. We elucidate direct effects of ingenol mebutate on primary keratinocytes, patient-derived SCC cells, and a SCC cell line. Transcriptional profiling followed by pathway analysis was performed on ingenol mebutate-treated primary keratinocytes and patient-derived SCC cells to find key mediators and identify the mechanism of action. Activation of the resulting pathways was confirmed in cells and human skin explants and supported by a phosphorylation screen of treated primary cells. The necessity of these pathways was demonstrated by inhibition of certain pathway components. Ingenol mebutate inhibited viability and proliferation of all keratinocyte-derived cells in a biphasic manner. Transcriptional profiling identified the involvement of PKC/MEK/ERK signaling in the mechanism of action and inhibition of this signaling pathway rescued ingenol mebutate-induced cell death after treatment with 100 nmol/L ingenol mebutate, the optimal concentration for the first peak of response. We found the interleukin decoy receptors IL1R2 and IL13RA2 induced by ingenol mebutate in a PKC/MEK/ERK-dependent manner. Furthermore, siRNA knockdown of IL1R2 and IL13RA2 partially rescued ingenol mebutate-treated cells. In conclusion, we have shown that ingenol mebutate-induced cell death is mediated through the PKCδ/MEK/ERK pathway, and we have functionally linked the downstream induction of IL1R2 and IL13RA2 expression to the reduced viability of ingenol mebutate-treated cells.

Effects of dipotassium-trioxohydroxytetrafluorotriborate, K2[B3O3F4OH], on cell viability and gene expression of common human cancer drug targets in a melanoma cell line

Recently it was found that dipotassium-trioxohydroxytetrafluorotriborate, K2(B3O3F4OH), is a potent and highly specific inhibitor of precancerous cell processes. We conducted gene expression profiling of human melanoma cells before and after treatment with two concentrations (0.1 and 1 mM) of this boron inorganic derivative in order to assess its effects on deregulation of genes associated with tumor pathways. Parallel trypan blue exclusion assay was performed to assess the cytotoxicity effects of this chemical. Treatment with K2(B3O3F4OH) induced a significant decrease of cell viability in melanoma cellline at both tested concentrations. Furthermore, these treatments caused deregulation of more than 30 genes known as common anti-tumor drug targets. IGF-1 and hTERT were found to be significantly downregulated and this result may imply potential use of K2(B3O3F4OH) as an inhibitor or human telomerase and insulin-like growth factor 1, both of which are associated with various tumor pathways.

Management of Aggressive Basal Cell Carcinoma

Basal cell carcinoma (BCC), a malignant neoplasm derived from nonkeratinizing cells that originate in the basal layer of the epidermis, is the most common cancer in humans. Several factors such as anatomic location, histologic features, primary versus recurrent tumors, and patient characteristics influence the treatment modality for basal cell carcinoma. Mohs micrographic surgery facilitates optimal margin control and conservation of normal tissue for the management of aggressive basal cell carcinoma, basal cell carcinoma on the head, neck, or genitals, recurrent basal cell carcinoma, those with infiltrative histology or perineural invasion, and those occurring in immunosuppressed hosts; however, other treatment modalities may also be appropriately implemented for more indolent BCCs on non-high-risk sites. For the treatment of aggressive or advanced BCCs, surgical clearance with margin assessment is preferable whenever feasible, and at times, a multidisciplinary approach with adjuvant or rarely neoadjuvant therapy with targeted molecular therapeutic agents or radiation therapy when indicated.

Truncating mutation in the autophagy gene UVRAG confers oncogenic properties and chemosensitivity in colorectal cancers.

Autophagy-related factors are implicated in metabolic adaptation and cancer metastasis. However, the role of autophagy factors in cancer progression and their effect in treatment response remain largely elusive. Recent studies have shown that UVRAG, a key autophagic tumour suppressor, is mutated in common human cancers. Here we demonstrate that the cancer-related UVRAG frameshift (FS), which does not result in a null mutation, is expressed as a truncated UVRAGFS in colorectal cancer (CRC) with microsatellite instability (MSI), and promotes tumorigenesis. UVRAGFS abrogates the normal functions of UVRAG, including autophagy, in a dominant-negative manner. Furthermore, expression of UVRAGFS can trigger CRC metastatic spread through Rac1 activation and epithelial-to-mesenchymal transition, independently of autophagy. Interestingly, UVRAGFS expression renders cells more sensitive to standard chemotherapy regimen due to a DNA repair defect. These results identify UVRAG as a new MSI target gene and provide a mechanism for UVRAG participation in CRC pathogenesis and treatment response.

Abstract 1522: Survival of skin cancer tumor initiating cells requires the Ezh2 polycomb group protein

Abstract Epidermal squamous cell carcinoma is among the most common cancers in humans. These tumors are comprised of phenotypically diverse of cells that display varying potential for proliferation and differentiation. Polycomb group (PcG) proteins, including Ezh2, are important candidate stem cell maintanence proteins. Our previous study showed that Ezh2-enriched epidermal cancer stem cells (ECS cells) represent a minority of cells in tumors, yet drive aggressive tumor formation. In the present study, we show that Ezh2 is required for ECS cell survival, migration, invation and tumor formatiom and this is associated with increased histone H3 trimethylationon lysine 27, a mark of Ezh2 action. We also show that Ezh2 knockdown or treatment with Ezh2-selective inhibitors, GSK126 or EP-6438, reduce Ezh2 level and activity, leading to reduced spheroid formation, migration, invasion and tumor formation. Use of these inhibitors was associated with reduced ECS cell vaibility and induction of apoptosis. These studies indicate that epidermal squamous cell carcinoma cells contain a subpopulation of cancer stem cells-like tumor initiating cells that are enriched in Ezh2 expression and that Ezh2 is required for optimal survival of these cells and tumor formation. These studies suggest that treatment with Ezh2 inhibitors may be a strategy for reducing epidermal cancer stem cell survival and supressing tumor formation. Citation Format: Gautam Adhikary, Dan Grun, Candace Kerr, Sivaprakasam Balasubramanian, Ellen Rorke, Wen Xu, Richard Eckert. Survival of skin cancer tumor initiating cells requires the Ezh2 polycomb group protein. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1522. doi:10.1158/1538-7445.AM2015-1522

Abstract 145: HOTTIP, an oncogenic long non-coding RNA, is frequently up-regulated in hepatocellular carcinoma and is negatively regulated by tumor suppressive microRNA miR-125b

Abstract Hepatocellular carcinoma (HCC) is one of the most common human cancers. Due to the lack of early diagnostic and effective treatment modalities, the mortality of HCC is high. The development and progression of HCC is a multistep process driven by the accumulation of genetic and epigenetic alterations. Recently, emerging evidence has suggested the role of long non-coding RNAs (lncRNAs) in human carcinogenesis. Herein, by profiling the expression of 88 well-annotated lncRNAs, we identified that HOTTIP was the most significantly up-regulated lncRNA (81%, 57/70) in human HCCs, even in early stage of HCC formation. Functionally, knockdown of HOTTIP attenuated HCC cell proliferation in vitro and markedly abrogated tumorigenicity in vivo. In addition, knockdown of HOTTIP also inhibited migratory ability of HCC cells and significantly abrogated lung metastasis in orthotopic implantation model in nude mice. HOTTIP is an antisense lncRNA mapped to the distal end of the HOXA gene cluster. Knockdown of HOTTIP significantly suppressed the expression of a number of HOXA genes. Furthermore, we identified miR-125b as a post-transcriptional regulator of HOTTIP. Ectopic expression of miR-125b abolished HOTTIP-coupled luciferase activity and suppressed the endogenous level of HOTTIP. Moreover, in human HCCs, HOTTIP expression negatively correlated with that of miR-125b. In Summary, our findings suggest that HOTTIP is a novel oncogenic lncRNA, with miR-125b being its negative regulator. It contributes to hepatocarcinogenesis by regulating the expression of its neighboring protein-coding genes. Citation Format: Felice H. Tsang, Sandy L. Au, Lai Wei, Dorothy N. Fan, Joyce M. Lee, Carmen C. Wong, Irene O. Ng, Chun-Ming Wong. HOTTIP, an oncogenic long non-coding RNA, is frequently up-regulated in hepatocellular carcinoma and is negatively regulated by tumor suppressive microRNA miR-125b. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 145. doi:10.1158/1538-7445.AM2015-145

Abstract 3187: Depleting cells expressing fibroblast activation protein disrupts tumor-promoting desmoplasia

Abstract Solid tumors recruit and activate a heterogeneous population of non-transformed stromal cells (CASCs) in the tumor microenvironment (TME). There has been growing interest in the field to develop strategies to treat cancer and circumvent resistance to therapy by targeting CASCs. Defining the phenotypic subsets and the function of distinct subpopulations including myofibroblasts (defined by the expression of SMA) and the overlapping but distinct population of CASCs expressing Fibroblast Activation Protein (FAP) will be critical to informing the rational design of stromal-targeted therapies. FAP is a membrane serine protease that is selectively up-regulated in CASCs including cancer-associated fibroblasts (CAFs), mesenchymal stem cells (MSCs), and a subset of M2 macrophages, of virtually all common human epithelial cancers. Based on its selective expression on CASCs across a wide range of tumor types, we engineered FAP-specific chimeric antigen receptor expressing T cells (FAP-CAR T cells) and adoptively transferred them into tumor bearing mice to: 1) define the requirement for FAP+ cells for the accumulation and maintenance of a desmoplastic matrix; 2) define the relationship between the degree of desmoplasia, the capacity of FAP-CAR T cells to disrupt the tumor stroma and to inhibit tumor growth; and 3) determine whether FAP-CAR T cells can inhibit tumor growth through immune independent mechanisms. We found that FAP+ CACSs are responsible for maintaining the desmoplastic response and that conditional depletion following treatment with FAP-CAR T cells inhibits growth of human lung cancer xenografts and mouse pancreatic tumors in an immune-independent fashion. Taken together with recently published studies (1-3), our data provide important distinctions between the function of FAP+ CASCs and SMA+ myofibroblasts and provide support for further development of FAP+ stromal cell-targeted therapies for a wide range of solid tumors. Reference: 1. Feig, C., Jones, J. O., Kraman, M., Wells, R. J., Deonarine, A., Chan, D. S., et al. (2013). Targeting CXCL12 from FAP-expressing carcinoma-associated fibroblasts synergizes with anti-PD-L1 immunotherapy in pancreatic cancer. Proc Natl Acad Sci USA 110, 20212-20217. 2. Ozdemir, B. C., Pentcheva-Hoang, T., Carstens, J. L., Zheng, X., Wu, C. C., Simpson, T. R., et al. (2014). Depletion of carcinoma-associated fibroblasts and fibrosis induces immunosuppression and accelerates pancreas cancer with reduced survival. Cancer Cell 25, 719-734. 3. Wang, L. C., Lo, A., Scholler, J., Sun, J., Majumdar, R. S., Kapoor, V., et al. (2014). Targeting fibroblast activation protein in tumor stroma with chimeric antigen receptor T cells can inhibit tumor growth and augment host immunity without severe toxicity. Cancer Immunol Res 2, 154-166. Citation Format: Albert Lo, Liang-Chuan S Wang, John Scholler, James Monslow, Diana Avery, Rebecca A. Evans, David J. Bajor, Amy C. Durham, Elizabeth L. Buza, Robert H. Vonderheide, Carl H. June, Steven M. Albelda, Ellen Puré. Depleting cells expressing fibroblast activation protein disrupts tumor-promoting desmoplasia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3187. doi:10.1158/1538-7445.AM2015-3187

Clinicopathologic and molecular characteristics of gastric cancer showing gastric and intestinal mucin phenotype.

Gastric cancer (GC), one of the most common human cancers, can be classified into gastric or intestinal phenotype according to mucin expression. TP53 mutation, allelic deletion of the APC gene and nuclear staining of β-catenin are frequently detected in the intestinal phenotype of GC, whereas CDH1 gene mutation, microsatellite instability and DNA hypermethylation of MLH1 are common events in the gastric phenotype of GC. Our Serial Analysis of Gene Expression (SAGE) and Escherichia coli ampicillin secretion trap (CAST) analyses revealed that CDH17, REG4, OLFM4, HOXA10, DSC2, TSPAN8 and TM9SF3 are upregulated in GC and that CLDN18 is downregulated in GC. Expression of CDH17, REG4, HOXA10 and DSC2 and downregulation of CLDN18 are observed in the intestinal phenotype of GC. In contrast, OLFM4 is expressed in the gastric phenotype of GC. Expression of TSPAN8, TM9SF3 and HER2 are not associated with either gastric or intestinal phenotypes. Ectopic CDX2 expression plays a key function in the GC intestinal phenotype. MUC2, CDH17, REG4, DSC2 and ABCB1 are direct targets of CDX2. Importantly, these genes encode transmembrane/secretory proteins, indicating that the microenvironment as well as cancer cells are also different between gastric and intestinal phenotypes of GC.