Evaluation of the BCL-2, PI3K, PARP-1, and HSP90 pathways in breast, lung and glial cell lines for identification of candidate genes as therapeutic targets for overcoming radioresistance.
| dc.contributor.advisor | Akudugu, John M. | en_ZA |
| dc.contributor.advisor | Serafin, Antonio M. | en_ZA |
| dc.contributor.author | Manunu, Bayanika | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences. Molecular Biology and Human Genetics. | en_ZA |
| dc.date.accessioned | 2021-11-05T10:01:07Z | en_ZA |
| dc.date.accessioned | 2022-02-22T10:23:24Z | en_ZA |
| dc.date.available | 2023-01-04T03:00:13Z | en_ZA |
| dc.date.issued | 2021-11 | en_ZA |
| dc.description | Thesis (PhD)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Cancer remains a major cause of mortality globally. This disease can be treated with surgery, chemotherapy or radiotherapy. Radiotherapy is an important modality to treat many types of cancers. About half of patients presenting with cancer are treated with radiotherapy throughout the duration of their disease. The effectiveness of radiotherapy is attributed to the capacity of radiation to cause damage to DNA which subsequently leads to cell death. Although radiotherapy is an effective cancer treatment, a large number of patients subsequently experience radio resistance and recurrence of their cancers. A number of molecular signalling pathways contribute to cellular resistance against radiotherapy, such as DNA damage repair and PI3K/Akt/mTOR pathways. Identifying signalling pathway-related genes associated with radio resistance of cancers may be helpful in designing targeted therapeutic strategies which could enhance the efficacy of radiotherapy for human cancers. Therefore, novel therapeutic radio sensitisers are needed in order to overcome radioresistant cancers and to improve the outcome of therapy. The main objective of this study was to identify the Bcl-2, PI3K, PARP-1 and Hsp90 pathway related gene families as candidate genes associated to radio resistance of human breast, lung and glial cancer cells following exposure to radiation, so as to establish potential gene targets that may be inhibited in order to sensitise radioresistant cells, and guide the development of more potent therapeutic approaches. This study found that the lung cancer cell line (A549) and the glioblastoma cell line (G28) were the most radioresistant cancer cells based on the gene function-specific numerical difference of the 12 highly expressed (upregulation and downregulation) genes from each cell line. This resistance was attributed to BAG1, MGMT, FOXO1 and DNAJA1 as candidate radio resistance related genes involved in apoptosis, DNA repair, PI3K and Hsp90 pathways, respectively. Furthermore, pre-treatment of A549 and G28 cells with small molecule inhibitors, Thioflavin S (against BAG1), O6-Benzylguanine (against MGMT), AS1842856 (against FOXO1), and 116-9e (against DNAJA1), singly resulted in modest radio sensitisation in A549 and G28 cells, modest radio sensitisation in A549 cells only, moderate radio sensitisation in both cell lines, and radioprotection in both cell lines, respectively. This array of radio modulation was observed at 2 Gy (fractional dose in conventional radiotherapy), indicating that might inform the design of radiotherapy when these target inhibitors are considered as adjuvants. These findings suggest that targeting radio resistance-related genes (BAG1, MGMT, and FOXO1) could potentially be effective in the treatment of radioresistant cancers, in particular, lung cancer and glioblastoma multiforme. However, validation of the current in vitro findings in a larger panel of cell lines is needed, and it would be instructive to perform research experiments at a preclinical level using in vivo models. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Kanker bly wêreldwyd 'n belangrike oorsaak van sterftes. Hierdie siekte kan behandel word met chirurgie, chemoterapie of radioterapie. Radioterapie is 'n belangrike manier om baie soorte kanker te behandel. Ongeveer die helfte van die pasiënte wat kanker kry, word gedurende die periode van hul siekte met radioterapie behandel. Die doeltreffendheid van radioterapie word toegeskryf aan die vermoë van bestraling om DNA-skade aan te rig wat dan tot seldood lei. Alhoewel radioterapie 'n effektiewe kankerbehandeling is, ervaar 'n groot aantal pasiënte hul weerstand en weer kanker. 'N Aantal molekulêre seinweë dra by tot sellulêre weerstand teen radioterapie, soos herstel van DNA-skade en PI3K / Akt / mTOR-weë. Die identifisering van seinverwante gene wat verband hou met stralingsweerstand van kanker, kan nuttig wees om doeltreffende terapeutiese strategieë te ontwerp wat die doeltreffendheid van radioterapie vir kankers by mense kan verhoog. Daarom is nuwe terapeutiese radiosensibiliseerders nodig om kanker met 'n stralingsweerstand te oorkom en die uitkoms van die terapie te verbeter. Die hoofdoel van hierdie studie was om die Bcl-2-, PI3K-, PARP-1- en Hsp90-padverwante geenfamilies te identifiseer as kandidaat-gene wat verband hou met radioweerstand van menslike bors-, long- en glial-kankerselle na blootstelling aan bestraling, asook moontlike geen teikens wat gerem kan word om radiobestande selle sensitief te maak en die ontwikkeling van sterker terapeutiese benaderings te lei. Hierdie studie het bevind dat die longkanker-sellyn (A549) en die glioblastoom-sellyn (G28) die mees radioweerstandige kankerselle was, gebaseer op die gene-funksiespesifieke numeriese verskil van die 12 sterk uitgedrukte (opregulasie en afregulering) gene van elke sellyn. Hierdie weerstand word toegeskryf aan BAG1, MGMT, FOXO1 en DNAJA1 as kandidaat-radioweerstandsverwante gene wat betrokke is by onderskeidelik apoptose, DNA herstel, PI3K en Hsp90 roetes. Verder het voorbehandeling van A549- en G28-selle met kleinmolekule-remmers, Thioflavin S (teen BAG1), O6-Benzylguanine (teen MGMT), AS1842856 (teen FOXO1) en 116-9e (teen DNAJA1) tot beskeie radiosensitisasie gelei in A549- en G28 -selle, slegs beskeie radiosensibilisering in A549 -selle, matige radiosensibilisering in beide sellyne en radiobeskerming in beide sellyne. Hierdie reeks radiomodulasie is waargeneem by 2 Gy (fraksionele dosis by konvensionele radioterapie), wat daarop dui dat dit die ontwerp van radioterapie kan inlig wanneer hierdie teiken -remmers as byvoegsels beskou word. Hierdie bevindings dui daarop dat die fokus op radioweerstandverwante gene (BAG1, MGMT en FOXO1) moontlik effektief kan wees in die behandeling van radioweerstandige kankers, veral longkanker en glioblastoma multiforme. Dit is egter nodig om die huidige in vitro - bevindings in 'n groter aantal sellyne te bekragtig, en dit sal insiggewend wees om navorsingseksperimente op 'n prekliniese vlak uit te voer met behulp in vivo modelle. | af_ZA |
| dc.embargo.terms | 2022-12-31 | en_ZA |
| dc.format.extent | 187 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/124291 | en_ZA |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject.lcsh | Cancer -- Radiotherapy -- Complications | en_ZA |
| dc.subject.lcsh | Radioresistance | en_ZA |
| dc.subject.lcsh | HER-2 protein | en_ZA |
| dc.subject.lcsh | Apoptosis | en_ZA |
| dc.subject.lcsh | UCTD | en_ZA |
| dc.title | Evaluation of the BCL-2, PI3K, PARP-1, and HSP90 pathways in breast, lung and glial cell lines for identification of candidate genes as therapeutic targets for overcoming radioresistance. | en_ZA |
| dc.type | Thesis | en_ZA |