Safety and efficacy of recombinant newcastle disease virus expressing human interleukin-12 as a potential vaccine in breast cancer
In this developing era, breast cancer still remains a life-threatening disease globally. However, oncolytic virotherapy has taken over interest as a promising non-conventional alternative to treating breast cancers. Newcastle disease virus (NDV), an avian paramyxovirus has been demonstrated with...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2019
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/90818/1/IB%202019%2026%20-%20IR.pdf |
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| Summary: | In this developing era, breast cancer still remains a life-threatening disease globally.
However, oncolytic virotherapy has taken over interest as a promising non-conventional
alternative to treating breast cancers. Newcastle disease virus (NDV), an avian
paramyxovirus has been demonstrated with significant oncolytic activity against cancer
based on numerous preclinical studies. Today, genetically modified viruses coding for
immunomodulatory agents, such as cytokines or chemokines, have come into focus.
Such engineered viruses are able to promote efficient immune responses against tumour
cells. The overall of this project aims to study the effects of a recombinant NDV
expressing human interleukin 12 (rAF-IL12) in the apoptotic and metastatic process in
MCF7 and MDA-MB231 human breast cancer cell lines. The parental NDV AF2240
was used as a positive control in this study. Notably, rAF-IL12 was able to maintain its
stability when passaged in specific pathogen free (SPF) eggs up to ten passages.
Furthermore it is considered safe as it selectively induced cytotoxic effects in chicken
and breast cancer cell lines while sparing non-cancerous breast cell line as demonstrated
through the MTT assay. The stability of each passaged rAF-IL12 was verified via
haemagglutination assay (HA), mean death time (MDT) and intracerebral pathogenicity
index (ICPI), while the IL12 was quantified through Enzyme-Linked Immunosorbent
Assay (ELISA). Comparable to AF2240, rAF-IL12 was also able to induce apoptosis
significantly based on several apoptotic assays. Both rAF-IL12 and AF2240 managed to
increase the percentage of G2/M and S phase in the cell cycle analysis while inducing
the percentage of apoptosis. Although both AF2240 and rAF-IL12 demonstrated
comparable in vitro apoptosis results, rAF-IL12 possessed significant (p<0.05) antimetastatic
activity in comparison to AF2240 based on metastasis related assays including
the in vitro scratch assay, migration/ invasion assay, human umbilical vein endothelial
cell (HUVEC) tube formation and rat aortic ring assay. Additionally, to further evaluate
the anti-tumour and anti-metastatic mechanism of rAF-IL12, in vivo studies were
conducted using 4T1-challenged BALB/c mice as a model of this study. The rAF-IL12 was proven to function as an improved tumour vaccine as it significantly (p<0.05)
reduced the size of tumour in comparison to the parental AF2240 virus. Apoptotic results
showed that the number of cancer cells in the tumour significantly (p<0.05) reduced after
28 days of intra-tumoural treatment with rAF-IL12 (27 HAU). In addition, rAF-IL12 was
able to inhibit the migration of cancer cells to other vital organs as opposed to the
untreated group. To further elucidate the apoptotic and anti-metastatic mechanism of
rAF-IL12 at molecular level, NanoString nCounter was conducted. Even though both
AF2240 and rAF-IL12 exhibited similar mechanism of action, rAF-IL12 was more
potent than AF2240 in terms of apoptosis and anti- metastasis activity. In conclusion,
both rAF-IL12 and AF2240 were able to inhibit the proliferation of breast cancer cells
and induce apoptosis in the in vitro studies; however, rAF-IL12 was able to demonstrate
significant (p<0.05) improved functionality in comparison to AF2240 alone based on the
in vivo studies. This proved that interleukin 12 was able to increase the immune response
against tumour cells by inducing cell death, anti-angiogenesis and anti-metastasis
effects, further improving the function of AF2240 as a potential vaccine in breast cancer. |
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