Publications by authors named "Pei Jean Tan"

Article Synopsis
  • Tumour-associated angiogenesis is crucial for cancer growth and spread; current anti-angiogenic drugs targeting VEGFA/VEGFR2 often face resistance and variable effectiveness.
  • This study used zebrafish to discover canthin-6-one, an indole alkaloid that inhibits the development of blood vessels in zebrafish and human cells without affecting the VEGFA/VEGFR2 pathway.
  • Canthin-6-one shows promise as a new anti-angiogenic treatment, particularly in combination with existing drugs like sunitinib, by effectively disrupting tumour-associated angiogenesis.
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Lymphangiogenesis, the formation of new lymphatic vessels from pre-existing vasculature, plays critical roles in disease, including in cancer metastasis and chronic inflammation. Preclinical and recent clinical studies have now demonstrated therapeutic utility for several anti-lymphangiogenic agents, but optimal agents and efficacy in different settings remain to be determined. We tested the anti-lymphangiogenic property of 3,4-Difluorobenzocurcumin (CDF), which has previously been implicated as an anti-cancer agent, using zebrafish embryos and cultured vascular endothelial cells.

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DNA mismatch repair (MMR) deficiency has been associated with a higher risk of developing colorectal, endometrial, and ovarian cancer, and confers resistance in conventional chemotherapy. In addition to the lack of treatment options that work efficaciously on these MMR-deficient cancer patients, there is a great need to discover new drug leads for this purpose. In this study, we screened through a library of commercial and semisynthetic natural compounds to identify potential synthetic lethal drugs that may selectively target MLH1 mutants using MLH1 isogenic colorectal cancer cell lines and various cancer cell lines with known MLH1 status.

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Natural products are prolific producers of diverse chemical scaffolds, which have yielded several clinically useful drugs. However, the complex features of natural products present challenges for identifying bioactive molecules using high-throughput screens. For most assays, measured endpoints are either colorimetric or luminescence based.

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Poor prognosis of most cancer patients is in part, due to limited therapeutic options. Furthermore, as chemotherapy remains the standard-of-care for several cancers, partial or lack of response remains a concern and compounding this are the adverse side effects of the treatment that severely impacts the quality of life and survival. In pursuit of improving treatment options, we have opted to investigate the unique chemical skeleton of natural compounds as anticancer therapies.

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Zebrafish represents a powerful in vivo model for phenotype-based drug discovery to identify clinically relevant small molecules. By utilizing this model, we evaluated natural product derived compounds that could potentially modulate Notch signaling that is important in both zebrafish embryogenesis and pathogenic in human cancers. A total of 234 compounds were screened using zebrafish embryos and 3 were identified to be conferring phenotypic alterations similar to embryos treated with known Notch inhibitors.

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Zebrafish is gaining prominence as an important vertebrate model for investigating various human diseases. Zebrafish provides unique advantages such as optical clarity of embryos, high fecundity rate, and low cost of maintenance, making it a perfect complement to the murine model equivalent in biomedical research. Due to these advantages, researchers in Malaysia are starting to take notice and incorporate the zebrafish model into their research activities.

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Ethnopharmacological Relevance: Several members of the genus Lignosus, which are collectively known as cendawan susu rimau (in Malay) or tiger׳s milk mushrooms (TMM), are regarded as important local medicine particularly by the indigenous communities in Malaysia. The mushroom sclerotia are purportedly effective in treating cancer, coughs, asthma, fever, and other ailments. The most commonly encountered Lignosus spp.

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Targeted therapy, the treatment of cancer based on an underlying genetic alteration, is rapidly gaining favor as the preferred therapeutic approach. To date, although natural products represent a rich resource of bio-diverse drug candidates, only a few have been identified to be effective as targeted cancer therapies largely due to the incompatibilities to current high-throughput screening methods. In this article, we review the utility of a zebrafish developmental screen for bioactive natural product-based compounds that target signaling pathways that are intimately shared with those in humans.

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Photodynamic therapy (PDT) is an alternative treatment for cancer that involves administration of a photosensitive drug or photosensitizer that localizes at the tumor tissue followed by in situ excitation at an appropriate wavelength of light. Tumour tissues are then killed by cytotoxic reactive oxygen species generated by the photosensitizer. Targeted excitation and photokilling of affected tissues is achieved through focal light irradiation, thereby minimizing systemic side effects to the normal healthy tissues.

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Photodynamic therapy (PDT) is a medical treatment that involves the irradiation of an administered photosensitizing drug with light of a particular wavelength to activate the photosensitizer to kill abnormal cells. To date, only a small number of photosensitizers have been clinically approved for PDT, and researchers continue to look for new molecules that have more desirable properties for clinical applications. Natural products have long been important sources of pharmaceuticals, and there is a great potential for discovery of novel chemotypes from under-explored biodiversities in the world.

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Background: Twenty-seven extracts from 26 plants were identified as photo-cytotoxic in the course of our bioassay guided screening program for photosensitisers from 128 extracts prepared from 64 terrestrial plants in two different collection sites in Malaysia - Royal Belum Forest Reserve in the State of Perak and Gunung Nuang in the State of Selangor. One of the photo-cytotoxic extracts from the leaves of Phaeanthus ophtalmicus was further investigated.

Results: The ethanolic extract of the leaves from Phaeanthus ophtalmicus was able to reduce the in vitro viability of leukaemic HL60 cells to < 50% when exposed to 9.

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