Page 83 - D. Cancer biology

Mitochondria associated genes alteration in GBM induces Avastin resistance.
Haseo Ryu, Sung Soo Kim, Jong Bae Park
Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer
Center, Goyang, Korea

BACKGROUND AIM

Glioblastoma(GBM) have been known as aggressive cancer To overcome the GBM, we should find target gene that
type that begins from brain. Temozolomide(TMZ) was typically causes avastin resistance. Especially mitochondria have
used to treat GBM but there were many case of recurrence. many great roles related to cancer like glycolysis, control
After the recurrence of TMZ, avastin was used to be treated redox, calcium homeostasis. Therefore, if the avastin
resistance target gene is found in the mitochondria gene,
additionally. But this was also recurrenced GBM by avastin then inhibiting that gene has great therapeutic potential.
resistance.
METHODS
In order to understand mechanism underlying avastin resistance in GBM, we made GBM mouse models by injecting U87 MG
(human GBM Tumor cell line) orthotopically. To make orthotopic Avastin resistance model, we use BALB/c nude mouse and
U87 MG cells were transplanted into left striatum of female BALB/c nude mouse by stereotactic injection. The treatment of
Avastin started 1 weeks after the injection and performed MRI analysis and proteomics analysis every week.
In order to find avastin resistance target gene related to mitochondria, we used engineered ascorbate peroxidase, APEX
technique. U87MG cells stably expressing matrix-V5-APEX2 were transplanted into left striatum of female BALB/c nude mouse
by stereotactic injection. For labeling mitochondria protein of U87MG, biotin-phenol labeling was initiated with H O in tissue
2 2
samples obtained for each time point .

RESULTS

Figure 1 Figure 2

Hypoxia

Figure 3 Figure 4

We observed that the cancer in the mouse model temporarily shrink but was found to recur by drug resistance in 6 weeks
after avastin treatment compared to vehicle treated mouse model of 4 weeks life span.(Fig. 1) Proteomics data described
gene expression associated mitochondria gene module was upregulated in avatin resistance model.(Fig. 2) To find the critical
mitochondria associated gene for GBM recurrence, we made mito matrix-V5-APEX2 expressing U87 MG cell line and injected
these cells to nude mouse brain.(Fig. 3) The samples of each group were pulled down using biotin labeled agarose bead.
APEX2 specific labeled samples were then used to perform proteomics analysis. Proteomics analysis revealed that
mitochondria related genes SQRKL; SQOR and MCU were highly upregulated in avastin resistance model.(Fig. 4)

CONCLUSION REFERENCES

Mitochondria has a major role in the energy metabolism of cells, apoptosis control. And the role of •Guntuku, L., Naidu, V. G. M., & Ganesh Yerra, V. (2016). Mitochondrial
mitochondria is also important in hypoxia induced avastin treatment. HIF1-A , regulator of cellular Dysfunction in Gliomas: Pharmacotherapeutic Potential of Natural
Compounds. Current Neuropharmacology, 14(6), 567–583.
and systemic homeostatic response to hypoxia was induced by mitochondria transmitting oxygen https://doi.org/10.2174/1570159x14666160121115641
•Li, X., Spelat, R., Bartolini, A., Cesselli, D., Ius, T., Skrap, M., … Torre, V. (2020).
level signal under hypoxia condition. That makes the cancer cells adapt well in hypoxia. Mechanisms of malignancy in glioblastoma cells are linked to mitochondrial
Among the mitochondrial genes, the genes that are tightly related to avastin resistence were Ca2+ uniporter upregulation and higher intracellular Ca2+ levels. Journal of
Cell Science, 133(6), jcs237503. https://doi.org/10.1242/jcs.237503
analyzed using apex techniques. As a result of analysis, 5 mitochondrial genes were sorted (ACO2, •Strickland, M., & Stoll, E. A. (2017). Metabolic Reprogramming in
MCU, OGDH, PDK1,SQRDL;SQOR) . Glioma. Frontiers in Cell and Developmental Biology, 5.
https://doi.org/10.3389/fcell.2017.00043
Through all this results, we have shown that the mitochondrial genes plays an important role in
avastin resistance. In particular, we plan to study how MCU, a mitochondrial calcium uniporter Contact information
located in mitochondria inner membrane, affects GBM cells. This is because MCU regulates the
calcium concentration inside mitochondria matrix, and this calcium concentration regulates the E-mail : 1905104@ncc.re.kr
production of ROS, which is important for cells to adapt to the hypoxia. . if we target that gene to
make drugs, it will be very helpful in treating GBM. Phone : 031) 920 - 2443