Altered Oncogene Activity Contributes to Compensation for Antisense Suppression of Bcl-2 and Tumor Resistance


Antisense oligonucleotides (oligos) have targeted growth regulatory proteins in prostate cancer models. To identify compensatory alterations in the expression of non-targeted genes we evaluate mono- and bispecific oligos targeting and equally suppressing the expression of the apoptosis inhibitory protein bcl-2. Bcl-2 is chosen because oligos directed towards it have entered clinical trials to restore apoptosis in cancer patients. Treated LNCaP cells compensate for the diminished bcl-2 by suppressing caspase-3 (an apoptosis promoter) while enhancing expression of AKT-1 (another apoptosis inhibitor), androgen receptor (AR) and its (p300 and IL-6) coactivators. Additional proteins are enhanced including PD-1, its ligand PD-L1 (immune checkpoint blockade markers) and fas-ligand, which activate apoptosis through the signal transduction, along with suppressor protein p53, polymerase transcription mediator MED-12 and signal transducer STAT-3. These alterations in expression may contribute to a greatly enhanced expression of the proliferation marker KI-67. This suggests that therapeutic approaches to restore apoptosis through suppression of bcl-2 lead to an altered expression in non-targeted genes involving apoptosis, androgen sensitivity, transcriptional activity and immune responsiveness, leads to an increase in proliferation (and a more androgen driven aggressive phenotype). In this study we evaluate the expression of two oncogenes (v-myc and K-ras) and find a large and significant enhancement of v-myc activity, which is produced by oligos targeting bcl-2 at the 5’ position. For K-ras, although significant suppression is produced by the bispecific targeting bcl-2 at the 3’ position, the percent change is relatively small compared with other compensatory alterations we have measured, and much less than in v-myc. Therefore, for the two oncogenes being evaluated, only increased v-myc activity is probably large enough to contribute to increased tumor aggressiveness in compensation for bcl-2 suppression.

Share and Cite:

Rubenstein, M. , Hollowell, C. and Guinan, P. (2015) Altered Oncogene Activity Contributes to Compensation for Antisense Suppression of Bcl-2 and Tumor Resistance. Open Journal of Apoptosis, 4, 62-70. doi: 10.4236/ojapo.2015.43007.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2011) Inhibition of Bcl-2 by Antisense Oligonucleotides Is Followed by a Compensatory Suppression of Caspase-3 in LNCaP Cells. European Journal of Clinical Medical Oncology, 3, 1-6.
[2] Mu, Z., Hachem, P. and Pollack, A. (2005) Antisense Bcl-2 Sensitizes Prostate Cancer Cells to Radiation. The Prostate, 65, 331-340.
[3] Yip, K.W., Mocanu, J.D., Au, P.Y., Sleep, G.T., Busson, D., Yeh, P., Gilbert, W.C., O’Sullivan, R., Gullane, B., Bastianutto, C. and Liu, F.F. (2005) Combination Bcl-2 Antisense and Radiation Therapy for Nasopharyngeal Cancer. Clinical Cancer Research, 11, 8131-8144.
[4] Yamanaka, K., Miyake, H., Zangemeister-wittke, U., Jansen, B. and Gleave, M. (2004) Novel Bispecific Antisense Oligonucleotides Inhibiting both Bcl-2 and Bcl-xL Expression Induce Apoptosis and Enhance Chemosensitivity in Human Androgen-Independent Prostate Cancer Cells. Proceedings AACR, 45, Abstract #2930. (Online)
[5] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2015) Following Inhibition of BCL-2 by Antisense Oligonucleotides Compensatory Suppression of Apoptosis Involves the Direct Signal Transduction Pathway of LNCaP Cells. Online Journal of Apoptosis, 4, 1-10.
[6] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2014) Additional Compensatory Mechanisms Altering Antisense Oligonucleotide Suppression of Bcl-2: Effects upon AKT-1 and STAT-3. In Vivo, 28, 867-870.
[7] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2011) In LNCaP Cells Enhanced Expression of the Androgen Receptor Compensates for Bcl-2 Suppression by Antisense Oligonucleotides. Therapeutic Advances in Urology, 3, 51-57.
[8] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2011) In LNCaP Cells Enhanced Expression of both Androgen Re- ceptor and Co-Stimulatory Protein p300 Compensate for Antisense Oligonucleotide Suppression of Bcl-2. Therapeutic Advances in Urology, 3, 243-250
[9] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2013) Increased Expression of the Androgen Receptor with p300 and IL-6 Coactivators Compensate for Oligonucleotide Suppression of Bcl-2. No Increased CREBBP or IL-4 Expression. Therapeutic Advances in Urology, 5, 85-93.
[10] Rubenstein M., Hollowell, C.M.P. and Guinan, P. (2013) Oligonucleotide Suppression of Bcl-2 in LNCaP Cells Is Compensated by Increased Androgen Sensitivity, p53 and Oncogene Activity, and Suppressed Caspase-3. Medical Oncology, 30, 599.
[11] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2014) In LNCaP Inhibition of Bcl-2 by Oligonucleotides Results in Compensatory Changes Involving Apoptosis, Transcription and Immunoregulation. Enliven: Journal of Genetic, Molecular and Cellular Biology, 1, 001.
[12] Sharma, P. and Allison, J. (2015) The Future of Immune Checkpoint Therapy. Science, 348, 56-61.
[15] Rubenstein, M., Anderson, K.M., Tsui, P. and Guinan, P. (2006) Synthesis of Branched Antisense Oligonucleotides Having Multiple Specificities: Treatment of Hormone Insensitive Prostate Cancer. Medical Hypotheses, 67, 1375-1380.
[16] Siegal, R.L., Miller, K.D. and Jemal, A. (2015) Cancer Statistics, 2015. CA: A Cancer Journal for Clinicians, 65, 5-29.
[17] Rubenstein, M. and Guinan, P. (2010) Bispecific Antisense Oligonucleotides Have Activity Comparable to Monospecifics in Inhibiting Expression of Bcl-2 in LNCaP Cells. In Vivo, 24, 489-493.
[18] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2010) Increased Prostate Specific Membrane Antigen Expression in LNCaP Cells Following Treatment with Bispecific Antisense Oligonucleotides Directed against Bcl-2 and EGFR. Medical Oncology, 27, 1212-1218.
[19] Rubenstein, M., Hollowell, C.M.P. and Guinan, P. (2011) Bispecific Oligonucleotides May Induce Interferon in LNCaP Cells Enhancing Surface Antigen Expression: Effect of Intra Strand Base Pair Complementarity. In Vivo, 25, 61-67.
[21] Oncogenex Website.
[22] Kling, J. (2010) Safety Signal Dampens Reception for Mipomersen Antisense. Nature Biotechnology, 28, 295-297.
[23] Koh, C.M., Bieberich, C.J., Dang, C.V., Nelson, W.G., Yegnasubramanian, S. and De Marzo, A.M. (2010) MYC and Prostate Cancer. Genes & Cancer, 1, 617-628.
[24] Ellwood-Yen, K., Gradber, T.G., Wongvipat, J., Iruela-Arispe, M.L., Zhang, J., Matusik, R., Thomas, G.V. and Sawyers, C.L. (2005) Myc-Driven Murine Prostate Cancer Shares Molecular Features with Human Prostate Tumors. Cancer Cell, 4, 223-238.

Copyright © 2022 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.