Abstract
The purine analogue, 8-chloro-adenosine (8-Cl-Ado), induces apoptosis in a number of multiple myeloma (MM) cell lines. This ribonucleoside analogue accumulates as a triphosphate and selectively inhibits RNA synthesis without perturbing DNA synthesis. Cellular RNA is synthesized by one of three polymerases (Pol I, II, or III); thus, the inhibition of one or more RNA polymerases may be mediating 8-Cl-Ado cytotoxicity. Here, we have addressed this question by dissecting the RNA-directed actions of 8-Cl-Ado in MM cells. Differential alterations in [3H]uridine incorporation were found in the three major classes of RNA after a 20-h exposure with 10 μM 8-Cl-Ado. The synthesis rate of Pol III transcripts, 5 S and tRNA, remained unchanged, whereas Pol I-mediated rRNA synthesis decreased by ∼20%. In contrast, mRNA synthesis, which is transcribed by Pol II, rapidly declined within 4 h and reached a 50% decrease, which was maintained for 20 h. Parallel to RNA synthesis inhibition, 8-Cl-Ado was maximally incorporated in the mRNA (>13 nmol/mg RNA), which was 5-fold higher than the tRNA and rRNA incorporation. Electrophoretic and radiographic analysis of newly synthesized and processed [14C]uridine-labeled transcripts indicated that the analogue blocks transcription elongation. Consistent with that result, high-performance liquid chromatography analysis of micrococcal nuclease and spleen phosphodi-esterase-digested RNA demonstrated that the analogue incorporation is at the 3′ terminus. In conclusion, our data demonstrate that in MM cells, 8-Cl-Ado is preferentially incorporated into mRNA, suggesting a propensity toward Pol II, and inhibits RNA synthesis by premature transcriptional chain termination.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7968-7974 |
| Number of pages | 7 |
| Journal | Cancer Research |
| Volume | 63 |
| Issue number | 22 |
| State | Published - Nov 15 2003 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Cancer Research
- Oncology
Cite this
RNA-Directed Actions of 8-Chloro-Adenosine in Multiple Myeloma Cells. / Stellrecht, Christine M.; Rodriguez, Carlos O.; Ayres, Mary; Gandhi, Varsha.
In: Cancer Research, Vol. 63, No. 22, 15.11.2003, p. 7968-7974.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - RNA-Directed Actions of 8-Chloro-Adenosine in Multiple Myeloma Cells
AU - Stellrecht, Christine M.
AU - Rodriguez, Carlos O.
AU - Ayres, Mary
AU - Gandhi, Varsha
PY - 2003/11/15
Y1 - 2003/11/15
N2 - The purine analogue, 8-chloro-adenosine (8-Cl-Ado), induces apoptosis in a number of multiple myeloma (MM) cell lines. This ribonucleoside analogue accumulates as a triphosphate and selectively inhibits RNA synthesis without perturbing DNA synthesis. Cellular RNA is synthesized by one of three polymerases (Pol I, II, or III); thus, the inhibition of one or more RNA polymerases may be mediating 8-Cl-Ado cytotoxicity. Here, we have addressed this question by dissecting the RNA-directed actions of 8-Cl-Ado in MM cells. Differential alterations in [3H]uridine incorporation were found in the three major classes of RNA after a 20-h exposure with 10 μM 8-Cl-Ado. The synthesis rate of Pol III transcripts, 5 S and tRNA, remained unchanged, whereas Pol I-mediated rRNA synthesis decreased by ∼20%. In contrast, mRNA synthesis, which is transcribed by Pol II, rapidly declined within 4 h and reached a 50% decrease, which was maintained for 20 h. Parallel to RNA synthesis inhibition, 8-Cl-Ado was maximally incorporated in the mRNA (>13 nmol/mg RNA), which was 5-fold higher than the tRNA and rRNA incorporation. Electrophoretic and radiographic analysis of newly synthesized and processed [14C]uridine-labeled transcripts indicated that the analogue blocks transcription elongation. Consistent with that result, high-performance liquid chromatography analysis of micrococcal nuclease and spleen phosphodi-esterase-digested RNA demonstrated that the analogue incorporation is at the 3′ terminus. In conclusion, our data demonstrate that in MM cells, 8-Cl-Ado is preferentially incorporated into mRNA, suggesting a propensity toward Pol II, and inhibits RNA synthesis by premature transcriptional chain termination.
AB - The purine analogue, 8-chloro-adenosine (8-Cl-Ado), induces apoptosis in a number of multiple myeloma (MM) cell lines. This ribonucleoside analogue accumulates as a triphosphate and selectively inhibits RNA synthesis without perturbing DNA synthesis. Cellular RNA is synthesized by one of three polymerases (Pol I, II, or III); thus, the inhibition of one or more RNA polymerases may be mediating 8-Cl-Ado cytotoxicity. Here, we have addressed this question by dissecting the RNA-directed actions of 8-Cl-Ado in MM cells. Differential alterations in [3H]uridine incorporation were found in the three major classes of RNA after a 20-h exposure with 10 μM 8-Cl-Ado. The synthesis rate of Pol III transcripts, 5 S and tRNA, remained unchanged, whereas Pol I-mediated rRNA synthesis decreased by ∼20%. In contrast, mRNA synthesis, which is transcribed by Pol II, rapidly declined within 4 h and reached a 50% decrease, which was maintained for 20 h. Parallel to RNA synthesis inhibition, 8-Cl-Ado was maximally incorporated in the mRNA (>13 nmol/mg RNA), which was 5-fold higher than the tRNA and rRNA incorporation. Electrophoretic and radiographic analysis of newly synthesized and processed [14C]uridine-labeled transcripts indicated that the analogue blocks transcription elongation. Consistent with that result, high-performance liquid chromatography analysis of micrococcal nuclease and spleen phosphodi-esterase-digested RNA demonstrated that the analogue incorporation is at the 3′ terminus. In conclusion, our data demonstrate that in MM cells, 8-Cl-Ado is preferentially incorporated into mRNA, suggesting a propensity toward Pol II, and inhibits RNA synthesis by premature transcriptional chain termination.
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UR - http://www.scopus.com/inward/citedby.url?scp=0345275863&partnerID=8YFLogxK
M3 - Article
C2 - 14633728
AN - SCOPUS:0345275863
VL - 63
SP - 7968
EP - 7974
JO - Journal of Cancer Research
JF - Journal of Cancer Research
SN - 0099-7013
IS - 22
ER -