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Lim KH, Idzwan MF, Sumarni MG, Kee CC, Amal NM, Lim KK, Gurpreet K. Heaviness of smoking index, number of cigarettes smoked and the Fagerstrom test for nicotine dependence among adult male Malaysians. Asian Pac J Cancer Prev 2012; 13:343-6. [PMID: 22502698 DOI: 10.7314/apjcp.2012.13.1.343] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Two methods of identifying smokers with high nicotine dependence, the heaviness of smoking index (HSI) and number of cigarettes per day (CPD) were compared with the Fagerstrom test for nicotine dependence (FTND). The HSI, CPD and the FTND were administered to 316 adult Malaysian male, daily smokers aged between 25-64 years old in the Malaysian NCD Surveillance-1 Survey using a two-stage stratified random sampling of enumeration blocks and living quarters, via an interview based on a validated questionnaire. The cut-off point for classification of high nicotine dependence on the HSI was a score of four or higher, and for the heavy smoking category, smoking more than 20 cigarettes per day. Classification using each method was compared with classification by the FTND (score of six or more) as the reference standard. Sensitivity, specificity and kappa statistics for concordance between both measures and the FTND were evaluated. The HSI gave a similar prevalence rate of high nicotine dependence as the FTND. There was substantial agreement between the HSI and the FTND (kappa=0.63.), with moderate sensitivity (69.8%) and high specificity (92.5%). However, prevalence of high nicotine dependence using the CPD was 7% lower than the FTND. The heavy smoking category also showed fair agreement with the FTND (kappa=0.45) and moderate sensitivity (67.0%), but specificity was high (86.9%). The findings indicate that the HSI can be used as an alternative to the FTND in screening for high nicotine dependence among daily smokers in large population-based studies, while CPD may not be a suitable alternative to the FTND.
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Lim KH, Yang Y, Staudt LM. Pathogenetic importance and therapeutic implications of NF-κB in lymphoid malignancies. Immunol Rev 2012; 246:359-78. [PMID: 22435566 DOI: 10.1111/j.1600-065x.2012.01105.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Derangement of the nuclear factor κB (NF-κB) pathway initiates and/or sustains many types of human cancer. B-cell malignancies are particularly affected by oncogenic mutations, translocations, and copy number alterations affecting key components the NF-κB pathway, most likely owing to the pervasive role of this pathway in normal B cells. These genetic aberrations cause tumors to be 'addicted' to NF-κB, which can be exploited therapeutically. Since each subtype of lymphoid cancer utilizes different mechanisms to activate NF-κB, several different therapeutic strategies are needed to address this pathogenetic heterogeneity. Fortunately, a number of drugs that block signaling cascades leading to NF-κB are in early phase clinical trials, several of which are already showing activity in lymphoid malignancies.
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Wang-Gillam A, Wani S, Early DS, Edmundowicz SA, Mullady D, Murad F, Jonnalagadda S, Gao F, Hollander T, Langley EJ, Meyer G, Singh S, Kim PS, Lim KH, Linehan D, Azar R. A pilot study of evaluation of a phosphorylation signature from pancreatic cancer tumors. J Clin Oncol 2012. [DOI: 10.1200/jco.2012.30.15_suppl.e14584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e14584 Background: The development of targeted therapy in pancreatic cancer has been hindered by minimal material available for molecular analysis from diagnostic endoscopic ultrasound-guided fine-needle aspirations (EUS/FNA). Revealing the phosphorylation status of key pathway mediators would allow optimal selection of patients for kinase inhibitor clinical trials. We launched a pilot study to evaluate the feasibility of detecting phosphorylation signatures from FNA samples using an ultrasensitive multiplexed protein microarray platform (CEER, Prometheus). Methods: Patients who underwent routine diagnostic EUS/FNA for a suspicious lesion in the pancreas underwent two additional EUS passes. Mediators of multiple signaling pathways including HER1/EGFR, HER2, HER3, IGF-IR, and their downstream mediators, AKT, MEK, ERK, et al were evaluated by CEER. Circulating tumor cells (CTCs) and resected tumor specimens were collected as available from patients for comparison. Results: From January-September, 2011, 57 patients were enrolled with a planned final enrollment of 100. This is an interim analysis. Thirty-nine (68.4%) had carcinoma cytology, 9 had atypical and 9 had negative cytology. HER2 (median value of 18 CU vs. 2 CU, p = 0.021) and HER3 (median value of 547 CU vs. 168 CU, p = 0.008) showed significantly higher levels of phosphorylation in malignant FNAs over their counterparts with negative cytology. Robust levels of CK expression were also observed in FNAs with carcinoma cytology (median CK level 1030 CU vs. 106 CU, p = 0.007). The wide range of phosphorylation signatures detected indicates this is a feasible clinical approach. For example, the expression levels of phosphorylated PI3K were 16 (22.5% - low), 28 (39.4% - medium low), 23 (32.4% - medium high), and 2 (2.8% - high). The correlation of p PI3K between 2 passes was 0.59 (p = 0.018) based on the Spearman Correlation. A CEER comparison of FNA vs. surgical specimens and FNA vs. CTCs is forthcoming. Conclusions: Profiling the phosphorylation status of pancreatic cancer pathways from FNA samples is feasible. If further validated, patients with pancreatic cancer can be screened for targeted therapy by their phosphorylation signature.
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Fong SS, Zhao C, Yap WM, Loke SC, Lim KH. Inflammatory myofibroblastic tumour of the duodenum. Singapore Med J 2012; 53:e28-e31. [PMID: 22337197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Inflammatory myofibroblastic tumours (IMTs) of the duodenum and head of the pancreas are rare. They are of probable immunological aetiology and preoperatively indistinguishable from adenocarcinomas of the pancreatic head. We describe a patient with duodenal IMT and gastric outlet obstruction, and present a review of pancreatic head and duodenal IMTs in the literature. IMTs of the pancreatic head present as obstructive jaundice, while those of the duodenum present as gastric outlet obstruction. Surgery is the primary modality of treatment. Adjuvant chemotherapy and radiotherapy are controversial and reserved for incomplete resections and IMTs of a pathologically aggressive nature. Otherwise, recurrence is uncommon and surgery curative.
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Lim KH, Chung E, Khan A, Cao D, Linehan D, Ben-Josef E, Wang-Gillam A. Neoadjuvant therapy of pancreatic cancer: the emerging paradigm? Oncologist 2012; 17:192-200. [PMID: 22250057 DOI: 10.1634/theoncologist.2011-0268] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Pancreatic cancer remains one of the deadliest cancers due to difficulty in early diagnosis and its high resistance to chemotherapy and radiation. It is now clear that even patients with potentially resectable disease require multimodality treatment including chemotherapy and/or radiation to improve resectability and reduce recurrence. Tremendous efforts are currently being invested in refining preoperative staging to identify optimal surgical candidates, and also in developing various neoadjuvant or adjuvant regimens to improve surgical outcome. Although at present no studies have been done to directly compare the benefit of neoadjuvant versus adjuvant approaches, accumulating evidence suggests that the neoadjuvant approach is probably beneficial for a subset of the patient population, particularly those with borderline resectable disease in which complete surgical resection is almost certainly unachievable. In this article, we review the literature and rationales of neoadjuvant chemotherapy and chemoradiation, as well as their potential limitations and caveats. We also review the pathological findings following neoadjuvant therapies, and potential surgical complications that may be associated with neoadjuvant therapies.
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Kee CC, Jamaiyah H, Geeta A, Ali ZA, Safiza MNN, Suzana S, Khor GL, Rahmah R, Jamalludin AR, Sumarni MG, Lim KH, Faudzi YA, Amal NM. Sensitivity and specificity of waist circumference as a single screening tool for identification of overweight and obesity among Malaysian adults. THE MEDICAL JOURNAL OF MALAYSIA 2011; 66:462-467. [PMID: 22390102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Generalised obesity and central obesity are risk factors for Type II diabetes mellitus and cardiovascular diseases. Waist circumference (WC) has been suggested as a single screening tool for identification of overweight or obese subjects in lieu of the body mass index (BMI) for weight management in public health program. Currently, the recommended waist circumference cut-off points of > or = 94cm for men and > or =80cm for women (waist action level 1) and > or = 102cm for men and > or = 88cm for women (waist action level 2) used for identification of overweight and obesity are based on studies in Caucasian populations. The objective of this study was to assess the sensitivity and specificity of the recommended waist action levels, and to determine optimal WC cut-off points for identification of overweight or obesity with central fat distribution based on BMI for Malaysian adults. Data from 32,773 subjects (14,982 men and 17,791 women) aged 18 and above who participated in the Third National Health Morbidity Survey in 2006 were analysed. Sensitivity and specificity of WC at waist action level 1 were 48.3% and 97.5% for men; and 84.2% and 80.6% for women when compared to the cut-off points based on BMI > or = 25kg/m2. At waist action level 2, sensitivity and specificity were 52.4% and 98.0% for men, and 79.2% and 85.4% for women when compared with the cut-off points based on BMI (> or = 30 kg/m2). Receiver operating characteristic analyses showed that the appropriatescreening cut-off points for WC to identify subjects with overweight (> or = 25kg/m2) was 86.0cm (sensitivity=83.6%, specificity=82.5%) for men, and 79.1cm (sensitivity=85.0%, specificity=79.5%) for women. Waist circumference cut-off points to identify obese subjects (BMI > or = 30 kg/m2) was 93.2cm (sensitivity=86.5%, specificity=85.7%) for men and 85.2cm (sensitivity=77.9%, specificity=78.0%) for women. Our findings demonstrated that the current recommended waist circumference cut-off points have low sensitivity for identification of overweight and obesity in men. We suggest that these newly identified cut-off points be considered.
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Lim SW, Ting KN, Bradshaw TD, Zeenathul NA, Wiart C, Khoo TJ, Lim KH, Loh HS. Acalypha wilkesiana extracts induce apoptosis by causing single strand and double strand DNA breaks. JOURNAL OF ETHNOPHARMACOLOGY 2011; 138:616-23. [PMID: 22008878 DOI: 10.1016/j.jep.2011.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 07/26/2011] [Accepted: 10/03/2011] [Indexed: 05/20/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The seeds of Acalypha wilkesiana have been used empirically by traditional healers in Southwest Nigeria together with other plants as a powder mixture to treat patients with breast tumours and inflammation. AIM OF THE STUDY There is an increasing interest among researchers in searching for new anticancer drugs from natural resources, particularly plants. This study aimed to investigate the anticancer properties of Acalypha wilkesiana extracts and the characteristics of DNA damage against brain and lung cancer cells. MATERIALS AND METHODS The antiproliferative activity of Acalypha wilkesiana extracts (ethyl acetate, hexane, and ethanol) was examined on human glioma (U87MG), human lung carcinoma (A549), and human lung fibroblast (MRC5) cells. RESULTS Cell viability MTT assay revealed that ethyl acetate extract of the plant possessed significant antiproliferative effects against both U87MG (GI(50)=28.03 ± 6.44 μg/ml) and A549 (GI(50)=89.63 ± 2.12 μg/ml) cells (p value<0.0001). The hexane extract was found to exhibit crucial antiproliferative effects on U87MG (GI(50)=166.30 ± 30.50 μg/ml) (p value<0.0001) but not on A549 cells. Neither plant extract possessed noticeable antiproliferative effects on the non-cancerous MRC5 cells (GI(50)>300 μg/ml). The ethanol extract showed no antiproliferative effects on any cell line examined. Haematoxylin & Eosin (H & E) staining and single cell gel electrophoresis (SCGE) comet assay confirmed that plant extract-treated cells underwent apoptosis and not necrosis. SCGE comet assays confirmed that plant extracts caused both single strand (SSB) and double strand (DSB) DNA breaks that led to the execution of apoptosis. CONCLUSION The extracts (especially ethyl acetate and hexane) of Acalypha wilkesiana possess valuable cytotoxic effects that trigger apoptosis in U87MG and A549 cancer cells through induction of DNA SSBs and DSBs.
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Kashatus DF, Lim KH, Brady DC, Pershing NLK, Cox AD, Counter CM. RALA and RALBP1 regulate mitochondrial fission at mitosis. Nat Cell Biol 2011; 13:1108-15. [PMID: 21822277 PMCID: PMC3167028 DOI: 10.1038/ncb2310] [Citation(s) in RCA: 279] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 06/28/2011] [Indexed: 12/13/2022]
Abstract
Mitochondria exist as dynamic interconnected networks that are maintained through a balance of fusion and fission1. Equal distribution of mitochondria to daughter cells during mitosis requires fission2. Mitotic mitochondrial fission depends upon both the relocalization of large GTPase Drp1 to the outer mitochondrial membrane and phosphorylation of S616 on Drp1 by the mitotic kinase cyclin B/Cdk12. We now report that these processes are mediated by the small Ras-like GTPase RalA and its effector RalBP1 (RLIP76/RLIP1/RIP1)3,4. Specifically, the mitotic kinase Aurora A phosphorylates S194 of RalA, relocalizing it to the mitochondria, where it concentrates RalBP1 and Drp1. Furthermore, RalBP1 associates with cyclin B/Cdk1 kinase activity to foster phosphorylation of Drp1 on S616. Disrupting either RalA or RalBP1 leads to a loss of mitochondrial fission at mitosis, improper segregation of mitochondria during cytokinesis and a decrease in ATP levels and cell number. Thus, the two mitotic kinases Aurora A and cyclin B/Cdk1 converge upon RalA and RalBP1 to promote mitochondrial fission, the appropriate distribution of mitochondria to daughter cells and ultimately proper mitochondrial function.
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Shelat VG, Seah M, Lim KH. Doxycycline induced acute erosive oesophagitis and presenting as acute dysphagia. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 2011; 59:57-9. [PMID: 21751670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Drug induced oesophageal disease is common. Doxycycline is one of the commonest cause of drug induced oesophageal ulcers. The medical community often under recognizes the importance of drug induced oesophageal lesions and fails to deliver proper advice and instructions related to drug ingestion. The diagnosis is usually clinical although endoscopy is the gold standard diagnostic tool. Treatment is symptomatic with discontinuation of the drug often being sufficient. Long-term sequelae are infrequent and acute complications uncommon. CLINICAL PICTURE A 22-year-old college student was prescribed doxycycline capsules for acne and developed dysphagia. Upper gastrointestinal endoscopy revealed acute erosive oesophagitis. TREATMENT AND OUTCOME She was managed symptomatically with proton pump inhibitors and her dysphagia improved over a period of three days. She was discharged with proper advice regarding medication ingestion and proton pump inhibitor for four weeks. CONCLUSION Drug induced oesophageal disease is a preventable self-limiting condition. Proper advice regarding medication ingestion is essential for prevention.
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Lim KH, Sumarni MG, Kee CC, Christopher VM, Noruiza Hana M, Lim KK, Amal NM. Prevalence and factors associated with smoking among form four students in Petaling District, Selangor, Malaysia. Trop Biomed 2010; 27:394-403. [PMID: 21399579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A cross-sectional study was conducted among form four students of secondary schools in the District of Petaling, Selangor, Malaysia from February 2008 to June 2008 with the aim of quantifying the prevalence of smoking and identifying the psychosocial factors related to smoking among adolescents in this district. A two-stage stratified sampling strategy was used to obtain a sample of 1300 students based on an estimated prevalence of 10%. The response rate was 80.5% (1045 out of 1298 students). Results showed that prevalence of smoking was higher among male students (22.3%) compared to females (5.5%) and the median age at smoking initiation was lower among males compared to female smokers (14 years old vs 15 years old). Modifiable risk factors associated with smoking were "percentage of friends who smoke" (OR 2.94, 95% CI [1.71- 5.06]) and "having a brother who smokes" (OR 1.97, 95% CI [1.20-3.31]). There was also a correlation between smoking prevalence and the number of risk factors present. Intensification of health education and anti-smoking programmes and modification of external factors in early adolescence are recommended to prevent smoking initiation.
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Abstract
The genes encoding the Ras family of small GTPases are mutated to yield constitutively active GTP-bound oncogenic proteins in one third of all human cancers. Oncogenic Ras binds to and activates a number of proteins that promote tumorigenic phenotypes, including the family of Ral guanine nucleotide exchange factors (RalGEF). Activated RalGEFs convert the Ral family of small GTPases, composed of RalA and RalB, from an inactive GDP-bound state to an active GTP-bound state. As both RalA and RalB have been implicated in a variety of tumorigenic phenotypes, we sought to determine which proteins downstream of Rals promote transformation and tumorigenesis. Here, we report that shRNA-mediated knockdown of the Ral effector proteins Sec5 and Exo84, but less so in the case of RalBP1, reduced oncogenic RalGEF-mediated transformation and oncogenic Ras-driven tumorigenic growth of human cells. These results suggest that Rals promote oncogenic Ras-mediated tumorigenesis through, at least in part, Sec5 and Exo84.
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Paramasvaran S, Sani RA, Hassan L, Krishnasamy M, Jeffery J, Oothuman P, Salleh I, Lim KH, Sumarni MG, Santhana RL. Ectoparasite fauna of rodents and shrews from four habitats in Kuala Lumpur and the states of Selangor and Negeri Sembilan, Malaysia and its public health significance. Trop Biomed 2009; 26:303-311. [PMID: 20237444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A total of 204 rodents comprising 14 host species from four different habitats were examined. Nine rodent species were trapped from the forest and another five species were trapped from the coastal, rice field and urban habitats. Rattus rattus diardii (67%) was the predominant rodent species examined. Fifty six (47.3%) rodents and shrews were found to be infested with at least one of the 20 species of ectoparasite recovered. Mites belonging to the family Trombiculidae were the predominant ectoparasite species recovered. Ticks belonging to the family Ixodidae were recovered mainly from the forest dwelling rodents. Polyplax spinulosa and Hoplopleura pacifica were the common lice species found infesting the urban rodents. Xenopsylla cheopis was the only flea species recovered. The following ecto-parasites have been incriminated as important vectors or as mechanical carriers for the transmission of zoonotic diseases: Ixodes granulatus, Dermacentor sp. Haemaphysalis sp., Amblyomma sp. Ascoschoengastia indica, Leptotrombidium deliense, Ornithonyssus bacoti, Laelaps nuttalli, H. pacifica, P. spinulosa and Xenopsylla cheopis. Urban and forest rodents were significantly higher in ecto-parasitic infestation, compared to rats from the other two habitats. However, there was no significant statistical association between male and female rodents infested with ectoparasites.
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Lim KH, Sumarni MG, Amal NM, Hanjeet K, Wan Rozita WM, Norhamimah A. Tobacco use, knowledge and attitude among Malaysians age 18 and above. Trop Biomed 2009; 26:92-9. [PMID: 19696733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study aims to determine the level of knowledge and to understand their attitude towards smoking and secondly to determine how sociodemographic background, smoking status and knowledge on the health risks of smoking contribute toward the development of such attitude. A total of 10,545 respondents age 18 years and above across Malaysia were interviewed. Results indicated that level of knowledge and attitude varied by gender, education level, smoking status, age, ethnicity and smoker category. Smokers' low education, poor knowledge on the dangers of smoking and being males had more positive or greater impact on their attitudes towards smoking. Formulation and implementation of a holistic programme aimed at increasing knowledge and attitude change that accounts for sociodemographic background of the population is recommended in order to bring down smoking rates and thus reduce smoking related health problems in this country.
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Paramasvaran S, Sani RA, Hassan L, Hanjeet K, Krishnasamy M, John J, Santhana R, Sumarni MG, Lim KH. Endo-parasite fauna of rodents caught in five wet markets in Kuala Lumpur and its potential zoonotic implications. Trop Biomed 2009; 26:67-72. [PMID: 19696729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Rodents were collected from five wet markets (Chow Kit, Dato Keramat, Setapak, Jinjang and Kepong) in Kuala Lumpur, Federal Territory between March to April 2006. Ninety seven rats were trapped using wire traps measuring 29 x 22 x 50 cm baited with fruits, coconuts, dried fish or sweet potatoes. A total of 17 different species of parasites were identified from three species of rats out of which 11 (65%) were identified to be zoonotic. The helminths identified from the urban rats were nematodes- Capillaria hepatica, Gongylonema neoplasticum, Heterakis spumosa, Heterakis sp., Masterphorus muris, Nippostrongylus brasiliensis, Physolaptera sp., Pterogodermatis sp., Rictularia tani and Syphacia muris; cestodes- Hymenolepis nana, Hymenolepis diminuta, Hymenolepis sabnema, Hymenolepis sp., Raillietina sp. and Taenia taeniaeformis, and acanthocephalan- Moniliformis moniliformis. The following parasites are of potential medical importance: C. hepatica, G. neoplasticum, R. tani, S. muris, H. diminuta, H. nana, Raillietina sp. and T. taeniaeformis.
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Lee YS, Lim KH, Guo X, Kawaguchi Y, Gao Y, Barrientos T, Ordentlich P, Wang XF, Counter CM, Yao TP. The cytoplasmic deacetylase HDAC6 is required for efficient oncogenic tumorigenesis. Cancer Res 2008; 68:7561-9. [PMID: 18794144 DOI: 10.1158/0008-5472.can-08-0188] [Citation(s) in RCA: 210] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Histone deacetylase inhibitors (HDACI) are promising antitumor agents. Although transcriptional deregulation is thought to be the main mechanism underlying their therapeutic effects, the exact mechanism and targets by which HDACIs achieve their antitumor effects remain poorly understood. It is not known whether any of the HDAC members support robust tumor growth. In this report, we show that HDAC6, a cytoplasmic-localized and cytoskeleton-associated deacetylase, is required for efficient oncogenic transformation and tumor formation. We found that HDAC6 expression is induced upon oncogenic Ras transformation. Fibroblasts deficient in HDAC6 are more resistant to both oncogenic Ras and ErbB2-dependent transformation, indicating a critical role for HDAC6 in oncogene-induced transformation. Supporting this hypothesis, inactivation of HDAC6 in several cancer cell lines reduces anchorage-independent growth and the ability to form tumors in mice. The loss of anchorage-independent growth is associated with increased anoikis and defects in AKT and extracellular signal-regulated kinase activation upon loss of adhesion. Lastly, HDAC6-null mice are more resistant to chemical carcinogen-induced skin tumors. Our results provide the first experimental evidence that a specific HDAC member is required for efficient oncogenic transformation and indicate that HDAC6 is an important component underlying the antitumor effects of HDACIs.
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Tan SY, Ye H, Liu H, Lim KH, Toh HC, Ng CFJ, Chung YFA, Wotherspoon AC, Du MQ. t(11;18)(q21;q21)-positive transformed MALT lymphoma. Histopathology 2008; 52:777-80. [PMID: 18439161 DOI: 10.1111/j.1365-2559.2008.03020.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
MESH Headings
- Aged
- Cell Transformation, Neoplastic/genetics
- Chromosomes, Human, Pair 11
- Chromosomes, Human, Pair 18
- Female
- Humans
- Lymphoma, B-Cell, Marginal Zone/genetics
- Lymphoma, B-Cell, Marginal Zone/pathology
- Male
- Middle Aged
- Translocation, Genetic
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Ancrile B, Lim KH, Counter CM. Oncogenic Ras-induced secretion of IL6 is required for tumorigenesis. Genes Dev 2007. [PMID: 17639077 DOI: 10.1101/gad.1549407genes] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Ras is mutated to remain in the active oncogenic state in many cancers. As Ras has proven difficult to target therapeutically, we searched for secreted, druggable proteins induced by Ras that are required for tumorigenesis. We found that Ras induces the secretion of cytokine IL6 in different cell types, and that knockdown of IL6, genetic ablation of the IL6 gene, or treatment with a neutralizing IL6 antibody retard Ras-driven tumorigenesis. IL6 appears to act in a paracrine fashion to promote angiogenesis and tumor growth. Inhibiting IL6 may therefore have therapeutic utility for treatment of cancers characterized by oncogenic Ras mutations.
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Abstract
Ras is mutated to remain in the active oncogenic state in many cancers. As Ras has proven difficult to target therapeutically, we searched for secreted, druggable proteins induced by Ras that are required for tumorigenesis. We found that Ras induces the secretion of cytokine IL6 in different cell types, and that knockdown of IL6, genetic ablation of the IL6 gene, or treatment with a neutralizing IL6 antibody retard Ras-driven tumorigenesis. IL6 appears to act in a paracrine fashion to promote angiogenesis and tumor growth. Inhibiting IL6 may therefore have therapeutic utility for treatment of cancers characterized by oncogenic Ras mutations.
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MESH Headings
- Animals
- Base Sequence
- Cell Line
- Cell Line, Tumor
- Gene Expression Regulation, Neoplastic
- Genes, ras
- Humans
- Interleukin-6/antagonists & inhibitors
- Interleukin-6/biosynthesis
- Interleukin-6/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, SCID
- Neoplasms, Experimental/etiology
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/immunology
- Neoplasms, Experimental/pathology
- RNA/genetics
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Lim KH. Ischaemic optic neuropathy. Singapore Med J 2007; 48:273-4. [PMID: 17384870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
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Lim KH, O'Hayer K, Adam SJ, Kendall SD, Campbell PM, Der CJ, Counter CM. Divergent roles for RalA and RalB in malignant growth of human pancreatic carcinoma cells. Curr Biol 2007; 16:2385-94. [PMID: 17174914 DOI: 10.1016/j.cub.2006.10.023] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 10/03/2006] [Accepted: 10/05/2006] [Indexed: 01/03/2023]
Abstract
BACKGROUND The Ral guanine nucleotide-exchange factors (RalGEFs) serve as key effectors for Ras oncogene transformation of immortalized human cells. RalGEFs are activators of the highly related RalA and RalB small GTPases, although only the former has been found to promote Ras-mediated growth transformation of human cells. In the present study, we determined whether RalA and RalB also had divergent roles in promoting the aberrant growth of pancreatic cancers, which are characterized by the highest occurrence of Ras mutations. RESULTS We now show that inhibition of RalA but not RalB expression universally reduced the transformed and tumorigenic growth in a panel of ten genetically diverse human pancreatic cancer cell lines. Despite the apparent unimportant role of RalB in tumorigenic growth, it was nevertheless critical for invasion in seven of nine pancreatic cancer cell lines and for metastasis as assessed by tail-vein injection of three different tumorigenic cell lines tested. Moreover, both RalA and RalB were more commonly activated in pancreatic tumor tissue than other Ras effector pathways. CONCLUSIONS RalA function is critical to tumor initiation, whereas RalB function is more important for tumor metastasis in the tested cell lines and thus argues for critical, but distinct, roles of Ral proteins during the dynamic progression of Ras-driven pancreatic cancers.
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Khairiah J, Lim KH, Ahmad-Mahir R, Ismail BS. Heavy metals from agricultural soils from Cameron Highlands, Pahang, and Cheras, Kuala Lumpur, Malaysia. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2006; 77:608-15. [PMID: 17123022 DOI: 10.1007/s00128-006-1106-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Accepted: 08/14/2006] [Indexed: 05/12/2023]
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Lim KH, Amal NM, Hanjeet K, Mashod MY, Wan Rozita WM, Sumarni MG, Hadzrik NO. Prevalence and factors related to smoking among secondary school students in Kota Tinggi District, Johor, Malaysia. Trop Biomed 2006; 23:75-84. [PMID: 17041555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Smoking among adolescent is a public health concern in Malaysia. Multiple studies on smoking prevalence and its related factors have been conducted in Malaysia, however, they were specific to either urban or rural areas alone. Studies in mixed settlement areas (urban, rural, land development area) had not been intensively investigated. This study reports the prevalence, demographic and factors related to smoking amongst form four students in the district of Kota Tinggi, Johor. A cross-sectional study of 16-year old secondary school students in Kota Tinggi district was conducted using two-stage stratified, proportionate sampling in July 2005. The study instrument used was a validated structured questionnaire on smoking and its related factors. Smoking prevalence was found to be 29.7%. More than 50% of male students were smokers. Prevalence was highest in FELDA (Federal Land Development Authority) settlement areas. Smoking was associated with having a brother or friend who smokes and poor academic performance. The study revealed that smoking prevalence was high, especially among male students in land development schemes. This situation will contribute to high smoking-related health problems in the future if proper preventive measures are not taken accordingly.
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Baines AT, Lim KH, Shields JM, Lambert JM, Counter CM, Der CJ, Cox AD. Use of retrovirus expression of interfering RNA to determine the contribution of activated K-Ras and ras effector expression to human tumor cell growth. Methods Enzymol 2006; 407:556-74. [PMID: 16757353 DOI: 10.1016/s0076-6879(05)07045-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cancer is a multistep genetic process that includes mutational activation of oncogenes and inactivation of tumor suppressor genes. The Ras oncogenes are the most frequently mutated oncogenes in human cancers (30%), with a high frequency associated with cancers of the lung, colon, and pancreas. Mutational activation of Ras is commonly an early event in the development of these cancers. Thus, whether mutated Ras is required for tumor maintenance and what aspects of the complex malignant phenotype might be promoted by mutated Ras are issues that remain unresolved for these and other human cancers. The recent development of interfering RNA to selectively impair expression of mutated Ras provides a powerful approach to begin to resolve these issues. In this chapter, we describe the use of retrovirus-based RNA interference approaches to study the functions of Ras and Ras effectors (Raf, RalA, RalB, and Tiam1) in the growth of pancreatic carcinoma and other human tumor cell lines. Finally, we also compare the use of constitutive and inducible shRNA expression vectors for analyses of mutant Ras function.
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Lim KH, Counter CM. Reduction in the requirement of oncogenic Ras signaling to activation of PI3K/AKT pathway during tumor maintenance. Cancer Cell 2005; 8:381-92. [PMID: 16286246 DOI: 10.1016/j.ccr.2005.10.014] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 10/13/2005] [Accepted: 10/21/2005] [Indexed: 11/17/2022]
Abstract
While tumors become addicted to oncogenes like Ras, the microenvironment in which tumor cells reside changes during tumorigenesis; the cells are surrounded initially by normal tissue and later by tumor tissue. Hence, we asked if Ras exerts its oncogenic effects through the same set of effectors during different stages of tumorigenesis. We now show in human cells that the Ras effector pathways MAPK, RalGEF, and PI3K are required to initiate tumor growth. Conversely, activation of the PI3K/AKT pathway replaced Ras once tumors formed, although other effectors were still activated independently of Ras, presumably by factors provided upon the establishment of a tumor microenvironment. Thus, as tumorigenesis progresses the addiction of cancers to their initiating oncogene is reduced to, at least in the case of Ras, the PI3K/AKT pathway.
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Noh JH, Park JK, Lee HJ, Kwon SK, Lee SH, Park JH, Ko KS, Rhee BD, Lim KH, Kim DJ. Depressive symptoms of type 2 diabetics treated with insulin compared to diabetics taking oral anti-diabetic drugs: a Korean study. Diabetes Res Clin Pract 2005; 69:243-8. [PMID: 16046024 DOI: 10.1016/j.diabres.2004.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Revised: 05/24/2004] [Accepted: 10/13/2004] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The purpose of this study was to examine the depressive symptoms of type 2 diabetic patients who were treated with insulin compared to those diabetics treated with oral anti-diabetic drugs in Korea. METHODS A total 204 outpatients with type 2 diabetes were invited to complete a questionnaire using the Beck depression inventory (BDI) to measure depressive symptoms. Age, gender, body mass index, serum lipid profile, and a social history including marital status, occupation and educational background were also assessed. The presence of diabetic complications was evaluated by examining the patients' medical records. Diabetic patients who were not treated with anti-diabetic drugs were excluded. All the study subjects were classified into two groups based on their mode of therapy: the oral drug group and insulin group. The insulin group included patients treated with insulin-oral drug combinations as well as those treated solely with insulin. RESULTS Overall, 32.4% of our diabetic subjects showed depressive symptoms with the criterion being a BDI score > or = 16. Compared to the oral drug group, the insulin group showed a significantly higher frequency of depressive symptoms (insulin group, 48.0%; oral drug group, 27.3%; p<0.01) and higher BDI scores (insulin group, 16.6+/-10.7; oral drug group, 12.6+/-8.7; p<0.01). Moreover, after an adjustment for social factors, the degree of hyperglycemia and the presence of diabetic complications, the insulin group showed a significantly higher frequency of depression (odds ratio 4.38, 95% CI 1.66-11.6, p=0.003), compared to the oral drug group. CONCLUSIONS The data showed that insulin treatment is related to the presence of depressive symptoms, and the importance of more careful psychological support of Korean insulin-treated type 2 diabetic patients is strongly suggested.
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