Alternative promoter usage and mRNA splicing pathways for parathyroid hormone-related protein in normal tissues and tumours

Southby, Justine; O'Keeffe, L M; Martın, Thomas; Gillespie, Matthew T.

doi:10.1038/bjc.1995.397

Cited by 72 publications

(80 citation statements)

References 25 publications

(6 reference statements)

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“…Human PTHrP expression is regulated predominantly on the transcriptional level by three different promoters (P1-P3). Of these, the P3 promoter (formerly called P2 promoter) has been shown to be active in all breast cancer cells [17]. Within this promoter, three regulatory DNA elements, an Ets, a stimulating protein-1 (Sp1) and a Smad3/4-binding site, have…”

Section: Introductionmentioning

confidence: 99%

Ets2 and protein kinase Cepsilon are important regulators of parathyroid hormone-related protein expression in MCF-7 breast cancer cells

Lindemann

Braig

Hauser

et al. 2003

Biochemical Journal

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Parathyroid hormone-related protein (PTHrP) promotes the metastatic potential and proliferation of breast cancer cells, and acts anti-apoptotically. In invasive MDA-MB-231 breast cancer cells, transforming growth factor β-regulated PTHrP synthesis is mediated by an Ets1/Smad3-dependent activation of the PTHrP P3 promoter. In the present study, we studied the regulation of PTHrP expression in non-invasive, Ets1-deficient and transforming growth factor β-resistant MCF-7 cells. We found PMA to be a strong stimulator of P3-dependent PTHrP expression in MCF-7 cells. Mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase (ERK) kinase 1 (MEK-1)/ERK1/2 inhibitor PD98059 interfered with this activity. Promoter studies revealed that the PMA effect depended on the Ets and stimulating protein-1 (Sp1)-binding sites. Of several Ets factors tested, Ets2, but not Ese-1, Elf-1 or Ets1, supported the PMA-dependent increase in promoter activity. PD98059 and a threonine to alanine mutation of the ERK1/2-responsive Ets2 phosphorylation site at position 72 inhibited the Ets2/PMA effect. Activated protein kinase C (PKC)ε could mimic PMA by stimulating the P3 promoter alone or in co-operation with Ets2 in an MEK-1/ERK1/2-dependent manner. Activated PKCα, although capable of co-operating with Ets2, failed to induce transcription from the P3 promoter on its own. The Ets2/PKCα synergistic effect was neither sensitive to PD98059 nor to Thr 72 /Ala 72 mutation. PMA neither increased the expression of Sp1 nor modulated the transcriptional activity of Sp1. However, it induced the displacement of a yet unknown factor from the Sp1-binding site, which may result in Sp1 recruitment to the promoter. Our results suggest an ERK1/2-dependent Ets2/PKCε synergism to be involved in PTHrP expression in MCF-7 breast cancer cells.

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Section: Introductionmentioning

confidence: 99%

Ets2 and protein kinase Cepsilon are important regulators of parathyroid hormone-related protein expression in MCF-7 breast cancer cells

Lindemann

Braig

Hauser

et al. 2003

Biochemical Journal

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“…Southby et al have reported that in their study, the splicing of exon VI to exon VII or exon IX was evident in all samples of RCC, suggesting that the 139-and 141-amino acid isoforms were common; in contrast, the 173-amino acid isoform was less often present. 8 Although the present study confirmed that these newly established cells produce all three isoforms, it has not been determined how these differing C-terminal regions may act biologically and thus which isoforms may play a key role in the development of hypercalcemia in patients. Furthermore, distinct secretory forms of PTHrP arising from these three transcripts have not yet been identified.…”

Section: Discussionmentioning

confidence: 41%

“…In SMRC-1, the number of chromosomes varied from 92 to 100 and the modal number was 95. The representative G-banded karyotype was 95~99 < 4n >, XXYY, +1 [7], +1 [3], add(1)(p36) [8], add(1) [6], der(1;3)(q10;p10) [9], der(1;3) [7], +2 [7], -3 [8], -3 [4], add(3)(q13) [4], del(3)(q27) [7], del (3) [3], +8~21mar. In SMRC-3, the number of chromosomes varied from 42 to 47 and the modal number was 45.…”

Section: Resultsmentioning

confidence: 99%

“…This RNA was reverse-transcribed using the GeneAmp Thermostable rTth Reverse Transcriptase RNA PCR Kit (PE Biosystems, Tokyo, Japan). For first-strand cDNA synthesis, 500 ng of total RNA from each sample and PTHrP reverse primer (Table 1) 8 were incubated with rTth polymerase at 70°C for 10 min. For PCR, the product was incubated with PTHrP forward primer (Table 1) at 40 cycles of 95°C for 30 s, 55°C for 30 s and 72°C for 1 min, followed by a final cycle at 72°C for 10 min.…”

Section: Reverse Transcription-polymerase Chain Reaction (Rt-pcr)mentioning

confidence: 99%

“…The polypeptides encoded by these three messenger RNA (mRNA) have been deduced to consist of 139, 141 and 173 amino acid isoforms, which differ in their C-terminal regions. 7,8 Parathyroid hormone-related protein circulates at ele-vated concentrations in patients with the humoral hypercalcemia of malignancy (HHM). [9][10][11] Humoral hypercalcemia of malignancy is most commonly associated with renal cell and squamous cell carcinomas.…”

Section: Introductionmentioning

confidence: 99%

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Production of parathyroid hormone‐related protein in two new cell lines of renal cell carcinoma

et al. 2001

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Background: Hypercalcemia is the most common of all paraneoplastic syndromes and has been reported to appear in up to 20% of patients with renal cell carcinoma (RCC). Humoral hypercalcemia of malignancy is believed to be induced when parathyroid hormone-related protein (PTHrP) is excessively produced in cancer cells and impairs the homeostasis of serum calcium concentrations.Methods: Cancer cells were isolated from a surgical specimen and successfully cultured in a monolayer. The present study describes the establishment and characterization of new cell lines of RCC.Results: Two different cell lines, designated SMRC-1 and SMRC-3, were established from human RCC, each of which had been continuously secreting PTHrP in vitro. The patient from whom the SMRC-3 cells were obtained was shown to have elevated levels of PTHrP and resultant hypercalcemia. Cultured SMRC-1 was spindle-shaped in morphology. SMRC-3 had pleomorphic polygonal shapes and formed typical epithelial monolayers. Both cell types secreted intact, C-terminal PTHrP and interleukin-6 in the culture medium. Cellular messenger RNA of PTHrP was analyzed by reverse transcriptase-polymerase chain reaction. The SMRC-1 cells showed chromosome numbers ranging from 42 to 47 with consistent structural abnormalities of add(4)(q23~25) and add(6)(q13). The chromosomal analysis of SMRC-3 revealed a modal number of 95 with consistent structural abnormalities of add(1)(p36) and der(1;3)(q10;p10). Conclusions: These cell lines could be good models for investigating the mechanism of PTHrP production and the relationship between this hormone and hypercalcemia.

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Calcitonin receptors, bone sialoprotein and osteopontin are expressed in primary breast cancers

Gillespie

Thomas

et al. 1997

Int. J. Cancer

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Several human breast cancer cell lines express the calcitonin receptor (CTR), but this has not been demonstrated previously in clinical breast cancers. We examined 18 primary breast cancers by reverse transcription‐PCR, for expression of CTR and of the bone proteins osteopontin (OPN) and bone sialoprotein (BSP). OPN and CTR were expressed by each of the tumours, and 7 (39%) additionally expressed an alternate form of CTR, whilst BSP was expressed by 13 tumours (72%). In situ hybridisation confirmed that expression of OPN and CTR was confined to the tumour cells. Expression of CTR, BSP and OPN may prove to be a useful marker for breast cancers, and their role in the homing of breast cancer cells to bone remains to be investigated. Int. J. Cancer 73:812–815, 1997. © 1997 Wiley‐Liss, Inc.

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Alternative promoter usage and mRNA splicing pathways for parathyroid hormone-related protein in normal tissues and tumours

Abstract: (Martin et

Cited by 72 publications

References 25 publications

Ets2 and protein kinase Cepsilon are important regulators of parathyroid hormone-related protein expression in MCF-7 breast cancer cells

Ets2 and protein kinase Cepsilon are important regulators of parathyroid hormone-related protein expression in MCF-7 breast cancer cells

Production of parathyroid hormone‐related protein in two new cell lines of renal cell carcinoma

Calcitonin receptors, bone sialoprotein and osteopontin are expressed in primary breast cancers

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