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Fulltext Stem Cells for Cancer Therapy: Translating the Uncertainties and Possibilities of Stem Cell Properties into Opportunities for Effective Cancer Therapy

Aldoghachi AF, Chong ZX, Yeap SK, Cheong SK, Ho WY, Ong AHK

Int J Mol Sci, 2023 Jan 05;24(2).
PMID: 36674525 DOI: 10.3390/ijms24021012

Cancer recurrence and drug resistance following treatment, as well as metastatic forms of cancer, are trends that are commonly encountered in cancer management. Amidst the growing popularity of personalized medicine and targeted therapy as effective cancer treatment, studies involving the use of stem cells in cancer therapy are gaining ground as promising translational treatment options that are actively pursued by researchers due to their unique tumor-homing activities and anti-cancer properties. Therefore, this review will highlight cancer interactions with commonly studied stem cell types, namely, mesenchymal stroma/stem cells (MSC), induced pluripotent stem cells (iPSC), iPSC-derived MSC (iMSC), and cancer stem cells (CSC). A particular focus will be on the effects of paracrine signaling activities and exosomal miRNA interaction released by MSC and iMSCs within the tumor microenvironment (TME) along with their therapeutic potential as anti-cancer delivery agents. Similarly, the role of exosomal miRNA released by CSCs will be further discussed in the context of its role in cancer recurrence and metastatic spread, which leads to a better understanding of how such exosomal miRNA could be used as potential forms of non-cell-based cancer therapy.
Fulltext Abnormalities of chromosome 11Q in three cases of acute myeloid leukemia

Ten SK, Khor MK, Khalid H, Lin HP, Ng SC, Cheong SK, et al.

Singapore Med J, 1992 Apr;33(2):164-6.
PMID: 1621121

The haematological findings and case history of 3 patients with the association of acute myeloid leukemia and translocation involving the long arm of chromosome no. 11 are presented. The recipient chromosome for the translocated material from chromosome 11 differs in all the three cases being namely chromosomes 1, 10 and 17.
Incorporating Insulin Growth Factor-1 into Regenerative and Personalized Medicine for Cardiovascular Disease: A Systematic Review

Gan QF, Lim YT, Foo CN, Yu CW, Woon CK, Cheong SK, et al.

Curr Stem Cell Res Ther, 2023;18(2):202-215.
PMID: 35392790 DOI: 10.2174/1574888X17666220407085901

BACKGROUND: Cardiovascular disease (CVD) is one of the world's leading causes of increased morbidity and mortality. Current interventions for CVD, including percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG), carry certain risks and complications, which may also affect the patient's quality of life. It is important to minimize those risks and complications while speeding up the recovery. Insulin Growth Factor-1 (IGF-1) is a growth factor responsible for cellular migration, proliferation, differentiation, and angiogenesis, which supports cardiovascular regeneration.
METHODS: In light of the current trend of regenerative medicine, the present review aims to pool data relating to the incorporation of IGF-1 in regenerative medicine and provide input on the current research gaps and concerns arising on translating this approach from benchwork into clinical settings.
RESULTS: Using the keywords IGF-1 'OR' Insulin Growth Factor 1 'AND' Mesenchymal Stem Cells 'AND' Tissue Healing from 2009 to 2020, we identified 160 and 52 from Medline and PubMed, screening out 202 articles due to non-fulfilment of the inclusion criteria.
CONCLUSION: Incorporating IGF-1 into regenerative and personalized medicine may be promising for treating CVD; however, the concerns include the role of IGF-1 in inducing cancer growth and its ability to migrate to the specific site of injury, especially for those who present with multiple pathologies should be addressed prior to its translation from bench work into clinical settings.
Acute leukemia and lymphoma in pregnancy, a retrospective study from a tertiary center in Malaysia

Fann RJ, D'Silv EC, Tanusha K, Wong TK, Lee BS, Sathar J, et al.

Med J Malaysia, 2023 Jul;78(4):429-436.
PMID: 37518908

INTRODUCTION: Most evidence about the management of cancer and hematological malignancy in pregnancy are derived from retrospective observational studies with a small sample size. Availability of sufficiently large data has enabled evidence-based decision-making in this clinical dilemma.
MATERIALS AND METHODS: Retrospective study looking into patients diagnosed with acute leukemia or lymphoma in pregnancy from 1st January 2014 to 1st January 2020 in Ampang General Hospital including newly or previously diagnosed and relapsed disease RESULTS: 37 cases of acute leukemia or lymphoma in pregnancy occurred in 34 patients. Majority of acute leukemia or lymphoma in pregnancy diagnosed in 1st trimester or in the setting of previously established or relapsed disease was therapeutically terminated. Thirteen pregnancies treated with antenatal chemotherapy resulted in livebirths except one stillbirth. More adverse obstetric outcomes are observed in pregnancies that did not receive antenatal chemotherapy, but association did not reach statistical significance. There was no significant difference in fetal outcome between cohort with and without antenatal chemotherapy. No treatment related mortality was observed in pregnancies with antenatal chemotherapy. Overall survival for newly diagnosed acute leukemia in pregnancy is significantly better with antenatal chemotherapy versus no antenatal chemotherapy.
CONCLUSION: Treatment with chemotherapy in 2nd trimester of pregnancy onwards appears to have tolerable risks with favorable obstetric and fetal outcome. Deferment of treatment for acute leukemia in pregnancy to after delivery may cause increased risk of maternal and fetal adverse outcome.
Human mesenchymal stromal cells could deliver erythropoietin and migrate to the basal layer of hair shaft when subcutaneously implanted in a murine model

Mok PL, Cheong SK, Leong CF, Chua KH, Ainoon O

Tissue Cell, 2012 Aug;44(4):249-56.
PMID: 22560724 DOI: 10.1016/j.tice.2012.04.002

Mesenchymal stromal cells (MSC) are an attractive cell-targeting vehicle for gene delivery. MIDGE (an acronym for Minimalistic, Immunologically Defined Gene Expression) construct is relatively safer than the viral or plasmid expression system as the detrimental eukaryotic and prokaryotic gene and sequences have been eliminated. The objective of this study was to test the ability of the human MSC (hMSC) to deliver the erythropoietin (EPO) gene in a nude mice model following nucleofection using a MIDGE construct. hMSC nucleofected with MIDGE encoding the EPO gene was injected subcutaneously in Matrigel at the dorsal flank of nude mice. Subcutaneous implantation of nucleofected hMSC resulted in increased hemoglobin level with presence of human EPO in the peripheral blood of the injected nude mice in the first two weeks post-implantation compared with the control groups. The basal layer of the hair shaft in the dermal layer was found to be significantly positive for immunohistochemical staining of a human EPO antibody. However, only a few basal layers of the hair shaft were found to be positively stained for CD105. In conclusion, hMSC harboring MIDGE-EPO could deliver and transiently express the EPO gene in the nude mice model. These cells could be localized to the hair follicle and secreted EPO protein might have possible role in hair regeneration.
Fulltext Extended and stable gene expression via nucleofection of MIDGE construct into adult human marrow mesenchymal stromal cells

Mok PL, Cheong SK, Leong CF, Chua KH, Ainoon O

Cytotechnology, 2012 Mar;64(2):203-16.
PMID: 22160354 DOI: 10.1007/s10616-011-9413-2

Human mesenchymal stromal cell (hMSC) is a potential target for cell and gene therapy-based approaches against a variety of different diseases. Whilst cationic lipofection has been widely experimented, the Nucleofector technology is a relatively new non-viral transfection method designed for primary cells and hard-to-transfect cell lines. Herein, we compared the efficiency and viability of nucleofection with cationic lipofection, and used the more efficient transfection method, nucleofection, to deliver a construct of minimalistic, immunologically defined gene expression encoding the erythropoietin (MIDGE-EPO) into hMSC. MIDGE construct is relatively safer than the viral and plasmid expression systems as the detrimental eukaryotic and prokaryotic gene and sequences have been eliminated. Using a plasmid encoding the luciferase gene, we demonstrated a high transfection efficiency using the U-23 (21.79 ± 1.09%) and C-17 (5.62 ± 1.09%) pulsing program in nucleofection. The cell viabilities were (44.93 ± 10.10)% and (21.93 ± 5.72)%, respectively 24 h post-nucleofection. On the other hand, lipofection treatment only yielded less than 0.6% efficiencies despite showing higher viabilities. Nucleofection did not affect hMSC renewability, immunophenotype and differentiation potentials. Subsequently, we nucleofected MIDGE-EPO using the U-23 pulsing program into hMSC. The results showed that, despite a low nucleofection efficiency with this construct, the EPO protein was stably expressed in the nucleofected cells up to 55 days when determined by ELISA or immunocytochemical staining. In conclusion, nucleofection is an efficient non-viral transfection approach for hMSC, which when used in conjunction with a MIDGE construct, could result in extended and stable transgene expression in hMSC.
Fulltext Recurrent multiple myeloma presenting as a breast plasmacytoma

Kalyani A, Rohaizak M, Cheong SK, Nor Aini U, Balasundaram V, Norlia A

Med J Malaysia, 2010 Sep;65(3):227-8.
PMID: 21939175

We describe a patient with multiple myeloma, who initially responded to chemotherapy and went into remission. She presented 10 months later with a right breast lump which was confirmed by core biopsy to be a plasmacytoma. Further treatment with radiotherapy, thalidomide and later second line chemotherapy appeared unsuccessful and she showed rapid disease progression with rising paraproteins and new extramedullary plasmacytoma lesions in the forehead, supraclavicular region, nasopharynx, liver, spleen, pancreas and paraaortic lymph nodes.
Fulltext Molecular responses during chemotherapy in acute myeloid leukemias in predicting poor-response to standard chemotherapy

Maha A, Cheong SK, Leong CF, Seow HF

Malays J Pathol, 2009 Dec;31(2):81-91.
PMID: 20514850 MyJurnal

Signal transduction pathways are constitutively expressed in leukaemic cells resulting in aberrant survival of the cells. It is postulated that in cells of chemo-sensitive patients, chemotherapy induces apoptotic signals leading to cell death while survival signals are maintained in cells of chemo-resistant patients. There is very little information currently, on the expression of these mediators in patients immediately after chemotherapy initiation. We examined the expression pattern of proinflammatory cytokines, signaling molecules of the PI3K and MAPK pathways molecules and death receptor, DR5 on paired samples at diagnosis and during chemotherapy in acute myeloid leukaemia patients treated with cytosine arabinoside and daunorubicin. The results were correlated with remission status one month after chemotherapy. We found that in chemo-sensitive patients, chemotherapy significantly increased the percentage of cases expressing TNF-alpha (p = 0.025, n = 9) and IL-6 (p = 0.002, n = 11) compared to chemo-resistant cases. We also observed an increased percentage of chemo-sensitive cases expressing DR5 and phosphorylated p38, and Jnk. Thus, expression of TNF-alpha, IL-6, DR5, phospho-p38 and phospho-Jnk may regulate cell death in chemo-sensitive cases. In contrast, a significantly higher percentage of chemo-resistant cases expressed phospho-Bad (p = 0.027, n = 9). IL-beta and IL-18 were also found to be higher in chemo-resistant cases at diagnosis and during chemotherapy. Thus, expression of various cellular molecules in leukaemic blasts during chemotherapy may be useful in predicting treatment outcome. These cellular molecules may also be potential targets for alternative therapy.
Fulltext Transfected human mesenchymal stem cells do not lose their surface markers and differentiation properties

Yap FL, Cheong SK, Ammu R, Leong CF

Malays J Pathol, 2009 Dec;31(2):113-20.
PMID: 20514854 MyJurnal

In this study, we evaluated the biological properties of human mesenchymal stem cells transfected (hMSC) with a plasmid vector expressing human cytokine interleukin-12 (IL-12). Surface markers were analysed by immunophenotyping using flow cytometry. Differentiation capability was evaluated towards adipogenesis and osteogenesis. We demonstrated that successfully transfected hMSC retained their surface immunophenotypes and differentiation potential into adipocytes and osteocytes. These results indicate that hMSC may be a suitable vehicle for gene transduction.
Fulltext Dendritic cell distribution in lymphomas

Hussin HN, Zulkifli FN, Phang KS, Cheong SK

Malays J Pathol, 2009 Dec;31(2):105-12.
PMID: 20514853 MyJurnal

Dendritic cells (DC) are specialized antigen presenting cells (APC) that have important roles in host defenses and in generating anti-tumour immune response. Altered frequency and maturation of DC have been reported in malignant tumours. We studied the distribution and maturation status of DC by immunohistochemistry, on the formalin-fixed, paraffin-embedded lymph node tissues of 32 histologically diagnosed lymphomas and 40 inflammatory conditions that were retrieved from the Department of Pathology, UKM Medical Centre, Kuala Lumpur. Our study showed a significant reduction in the total DC counts in the lymphoma tissues compared to the inflammatory conditions. The mature and immature DC counts were both significantly reduced (p = 0.008 and 0.001 respectively), although a greater reduction was observed in mature DC numbers. We also observed compartmentalization of DC where the immature DC were seen within the tumour tissues and the mature DC were more in peri-tumoural areas. Our findings were similar to other reports, suggesting that reduced numbers of DC appears to be a factor contributing to lack of tumour surveillance in these cases.
Fulltext Childhood idiopathic myelofibrosis: a case report and review of literature

Noor-Fadzilah Z, Leong CF, Sabariah MN, Cheong SK

Malays J Pathol, 2009 Dec;31(2):129-32.
PMID: 20514856 MyJurnal

Idiopathic myelofibrosis occurs predominantly in older adults. It is very rarely seen in children. We describe a 3-year-old girl with Down's syndrome who presented with recurrent chest infections associated with anaemia and easy bruising. There was mild hepatosplenomegaly. Full blood picture revealed pancytopaenia with leucoerythroblastosis with absence of circulating blast cells. Repeated attempts at bone marrow aspiration and trephine biopsy were unsuccessful. A trephine biopsy from the tibia showed depressed myelopoiesis and erythropoiesis, megakaryocytes with atypical morphology and increased bone marrow reticulin fibres, findings compatible with idiopathic myelofibrosis. She was treated symptomatically as she was clinically stable. Review of the English literature online yielded 46 reported cases of childhood idiopathic myelofibrosis with variable outcome from spontaneous remission to an indolent course with shortened survival. 6 cases evolved to another malignancy. 5 cases were associated with Down's syndrome.
Fulltext Stem cell transplantation in Malaysia and future directions

Fadilah SA, Leong CF, Cheong SK

Med J Malaysia, 2008 Oct;63(4):279-80.
PMID: 19385484 MyJurnal
Cell viability of acute myeloid leukaemia blasts in culture correlates with treatment outcome

Maha A, Cheong SK, Leong CF, Seow HF

Hematology, 2008 Feb;13(1):13-20.
PMID: 18534060 DOI: 10.1179/102453308X315762

Despite the advances in understanding the pathophysiology of acute myeloid leukaemia (AML), the cure rate for acute myeloid leukaemia patients remains low. Cytogenetic abnormalities and age are the prognostic factors that guide treatment decisions. However, many AML patients still die. The biological factors that influence treatment outcome are largely unknown. Thus, the objective of our study was to use the in vitro viability test to correlate with treatment outcome. Acute myeloid leukaemia blasts demonstrated differing ability to survive in culture. Our examination of blast phenotype at various days in culture showed two possible growth directions. First, cells underwent maturation by increased expression of CD16 and down-regulated CD34 (a haemopoietic stem cell marker). These cells also appeared to have undergone apoptosis. Alternatively, cells continued to survive in culture and maintained high expression of CD34. An MTT assay was carried out to determine viability after three days of culture. Lower optical density values were obtained for samples that underwent apoptosis and higher values were obtained for samples that survived in culture. Apoptosis was measured by Annexin V/propidium iodide staining. A comparison between results of MTT assay and duration of disease free survival revealed that a higher viability in vitro correlated significantly with shorter survival duration in the patient (R -0.761, p=0.002, n=13). Thus, this study further supports the hypothesis that AML patients with poor survival may be related to having blasts with a biologically more immature or stem cell-like nature.
In vitro expression of erythropoietin by transfected human mesenchymal stromal cells

Mok PL, Cheong SK, Leong CF, Othman A

Cytotherapy, 2008;10(2):116-24.
PMID: 18368590 DOI: 10.1080/14653240701816996

Mesenchymal stromal cells (MSC) are pluripotent progenitor cells that can be found in human bone marrow (BM). These cells have low immunogenicity and could suppress alloreactive T-cell responses. In the current study, MSC were tested for their capacity to carry and deliver the erythropoietin (EPO) gene in vitro.
Assessing donor chimerism using flow cytometry in paroxysmal nocturnal haemoglobinuria after stem cell transplantation--a case report

Azma RZ, Hamidah NH, Leong CF, Ainoon O, Cheong SK

Malays J Pathol, 2006 Dec;28(2):107-12.
PMID: 18376800

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired haemopoietic stem cell disorder arising from somatic mutation of the X-linked PIG-A gene which leads to deficiency of the glycosylphosphatidylinositol (GP1) membrane anchor proteins such as CD 59 (MIRL: membrane inhibitor of reactive lysis) and CD 55 (DAF: decay accelerating factor). Allogeneic peripheral blood stem cell transplant (PBSCT) is a curative mode of treatment in symptomatic PNH patients. Assessment of donor chimerism for PBSCT can be performed by various methods including short tandem repeat loci (STR) and variable number of tandem repeats (VNTR). Flow cytometry, which is much cheaper and faster, also can be used to assess engraftment in patients with PNH. Engrafted patients will show the presence of CD 55 and CD 59 on their red cells and white cells. We describe here the usefulness of flow cytometry in the assessment of donor chimerism following allogeneic PBSCT, in a case of PNH.
Mesenchymal stromal cell-like characteristics of corneal keratocytes

Choong PF, Mok PL, Cheong SK, Then KY

Cytotherapy, 2007;9(3):252-8.
PMID: 17464757

The unique potential of mesenchymal stromal cells (MSC) has generated much research interest recently, particularly in exploring the regenerative nature of these cells. Previously, MSC were thought to be found only in the BM. However, further studies have shown that MSC can also be isolated from umbilical cord blood, adipose tissue and amniotic fluid. In this study, we explored the possibility of MSC residing in the cornea.
Fulltext Haemophagocytic syndrome presenting as pyrexia of unknown origin

Fadilah SA, Raymond AA, Leong CF, Cheong SK

Med J Malaysia, 2006 Mar;61(1):91-3.
PMID: 16708741

Haemophagocytic syndrome (HPS) should be included in the differential diagnosis of pyrexia of unknown origin (PUO). The hallmark of HPS is the accumulation of activated macrophages that engulf haematopoietic cells in the reticuloendothelial system. We describe a patient with unexplained fever in which a final diagnosis of HPS was established in a bone marrow study.
G6PD deficiency with hemolytic anemia due to a rare gene deletion--a report of the first case in Malaysia

Ainoon O, Boo NY, Yu YH, Cheong SK, Hamidah HN

Hematology, 2006 Apr;11(2):113-8.
PMID: 16753852 DOI: 10.1080/10245330500155184

A 2-year-old Chinese boy was referred to Hospital UKM for investigation of recurrent episodes of dark-coloured urine and pallor since birth. He was born prematurely at 34 weeks gestation and developed severe early-onset neonatal jaundice requiring exchange blood transfusion. Screening at birth showed Glucose-6-phosphate dehydrogenase (G6PD) deficiency. On admission, physical examination revealed pallor, jaundice and mild hepatomegaly. Results of laboratory investigations showed a hemoglobin level of 11.0 g/dl with a hemolytic blood picture, reticulocytosis of 20% and red cell G6PD activity reported as undetectable. The patient's DNA was analysed for G6PD mutations by PCR-based techniques and DNA sequencing and results showed a 24 bp deletion of nucleotide 953-976 in the exon 9 of the G6PD gene. DNA analysis was also performed on blood samples of the patient's mother and female sibling confirming their heterozygous status, although both showed normal red cell G6PD activity levels. The patient was discharged well and his parents were appropriately advised on the condition and the importance of taking folic acid regularly. This is a first case report in Malaysia of G6PD deficiency causing chronic-hemolytic anemia. The rare 24 bp deletion causes the G6PD Nara variant, previously reported only in two other unrelated males, a Japanese and a Portuguese both with chronic hemolytic anemia.
Complex karyotypic abnormalities in a case of acute myeloid leukaemia--M4Eo

Leong CF, Azma RZ, Cheong SK, Salwati S, Sharifah NA

Malays J Pathol, 2005 Jun;27(1):45-50.
PMID: 16676693

A 25-year-old man was referred to Hospital UKM with a 2-week history of fever, productive cough and loss of appetite. Physical examination revealed an ill-looking, tachypnoeic young man. No obvious lymphadenopathy or organomegaly was noted. Examination of the respiratory system revealed right pleural effusion. Full blood picture demonstrated leukocytosis with 90% blasts, and bone marrow examination confirmed the diagnosis of acute myeloid leukemia (AML) French-American-British (FAB) classification of M4 with eosinophilia. His chromosome karyotyping showed complex karyotypic abnormalities. Cytological examination of the pleural fluid demonstrated numerous blast cells indicating leukemic infiltration of the lungs, which is a rare presentation in AML. He was then started on induction chemotherapy with intravenous daunorubicin and cytarabine. In the midst of treatment, he developed an episode of seizure and cerebro-spinal fluid cytology confirmed central nervous system (CNS) leukaemic infiltration. Additional intrathecal methotraxate was given. Repeat bone marrow examination done on day 15 of chemotherapy showed persistence of excess blasts indicating refractory AML. He was then reinduced with high dose cytarabine but to no avail. The disease progressed and he succumbed about 8 weeks after the initial diagnosis was made. We highlight here a case of AML-M4Eo with complex karyoyptic abnormalities presenting with leukaemic infiltration of the lungs and CNS which had imparted a bad prognosis for this subtype of AML, AML-M4Eo.
Detection of immunoglobulin gene rearrangement in B-cell malignancies

Ainoon O, Hamidah AB, Cheong SK, Hamidah HN

Malays J Pathol, 2000 Jun;22(1):5-11.
PMID: 16329531

Rearrangement of the immunoglobulin heavy chain (IgH) gene has been used as a marker of lineage and clonality in the diagnosis of B lymphoproliferative disorders. A number of PCR-based techniques have been developed to overcome the disadvantages of Southern blotting, the standard technique in detecting IgH gene rearrangement. Using an established seminested PCR technique with consensus primers to the V and J regions of the IgH gene, we analysed DNA prepared from peripheral blood and/or bone marrow specimens from 30 cases of known B cell malignancies (16 chronic lymphocytic leukemia, 11 acute lymphoblastic leukemia and 3 Non-Hodgkin Lymphoma), 3 cases of T lymphoproliferative disease and 3 cases of reactive lymphocytosis diagnosed in Hospital UKM to detect rearranged IgH gene. We found that monoclonality as represented by the presence of rearranged IgH gene were demonstrated in all the 30 cases. The PCR findings showed 100% concordance with the Southern blot analysis results which also showed rearranged IgH bands in all the 30 cases. We also found that none of the cases of T lymphoproliferative diseases and reactive lymphocytosis showed presence of rearranged IgH band, suggesting that the amplification using the IgH primers is lineage-specific. In conclusion, we find the PCR a useful method to detect IgH gene rearrangement in peripheral blood and bone marrow specimen. Since the PCR results are comparable to that of the Southern blotting in demonstrating B cell monoclonality and owing to its many advantages we feel that it can replace the Southern blot technique for the diagnosis of B cell malignancies.

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