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1.  Role of endoplasmic reticulum stress induction by the plant toxin, persin, in overcoming resistance to the apoptotic effects of tamoxifen in human breast cancer cells 
British Journal of Cancer  2013;109(12):3034-3041.
Background:
Persin is a plant toxin that displays synergistic cytotoxicity with tamoxifen in human breast cancer cell lines. Here, we examined the ability of persin to circumvent tamoxifen resistance and delineated the intracellular signalling pathways involved.
Methods:
The induction of apoptosis in tamoxifen-resistant and -sensitive breast cancer cells was measured by flow cytometry following treatment with persin±tamoxifen. Markers of endoplasmic reticulum stress (ERS) were analysed following treatment, and their causal role in mediating persin-induced apoptosis was determined using chemical inhibitors and RNA interference.
Results:
Cells that were resistant to an apoptotic concentration of tamoxifen maintained an apoptotic response to persin. Persin-induced apoptosis was associated with an increase in markers of ERS, that is, CHOP expression and XBP-1 splicing and was decreased by CHOP siRNA. The CASP-4 inhibitor Z-YVAD-FMK markedly inhibited persin-induced apoptosis in both tamoxifen-sensitive and -resistant cells.
Conclusion:
The cytotoxic effects of persin are CASP-4 dependent and mediated by CHOP-dependent and -independent ERS signalling cascades. Increased ERS signalling contributes to persin-induced reversal of tamoxifen resistance.
doi:10.1038/bjc.2013.693
PMCID: PMC3859954  PMID: 24178758
tamoxifen; persin; breast cancer; apoptosis; endoplasmic reticulum stress
2.  The prognostic and predictive value of serum CA19.9 in pancreatic cancer 
Annals of Oncology  2012;23(7):1713-1722.
Background
Current staging methods for pancreatic cancer (PC) are inadequate, and biomarkers to aid clinical decision making are lacking. Despite the availability of the serum marker carbohydrate antigen 19.9 (CA19.9) for over two decades, its precise role in the management of PC is yet to be defined, and as a consequence, it is not widely used.
Methods
We assessed the relationship between perioperative serum CA19.9 levels, survival and adjuvant chemotherapeutic responsiveness in a cohort of 260 patients who underwent operative resection for PC.
Results
By specifically assessing the subgroup of patients with detectable CA19.9, we identified potential utility at key clinical decision points. Low postoperative CA19.9 at 3 months (median survival 25.6 vs 14.8 months, P = 0.0052) and before adjuvant chemotherapy were independent prognostic factors. Patients with postoperative CA 19.9 levels >90 U/ml did not benefit from adjuvant chemotherapy (P = 0.7194) compared with those with a CA19.9 of ≤90 U/ml (median 26.0 vs 16.7 months, P = 0.0108). Normalization of CA19.9 within 6 months of resection was also an independent favorable prognostic factor (median 29.9 vs 14.8 months, P = 0.0004) and normal perioperative CA19.9 levels identified a good prognostic group, which was associated with a 5-year survival of 42%.
Conclusions
Perioperative serum CA19.9 measurements are informative in patients with detectable CA19.9 (defined by serum levels of >5 U/ml) and have potential clinical utility in predicting outcome and response to adjuvant chemotherapy. Future clinical trials should prioritize incorporation of CA19.9 measurement at key decision points to prospectively validate these findings and facilitate implementation.
doi:10.1093/annonc/mdr561
PMCID: PMC3387824  PMID: 22241899
adjuvant chemotherapy; CA19.9; pancreatic cancer; prognosis
3.  BAG-1 predicts patient outcome and tamoxifen responsiveness in ER-positive invasive ductal carcinoma of the breast 
British Journal of Cancer  2008;100(1):123-133.
BAG-1 (bcl-2-associated athanogene) enhances oestrogen receptor (ER) function and may influence outcome and response to endocrine therapy in breast cancer. We determined relationships between BAG-1 expression, molecular phenotype, response to tamoxifen therapy and outcome in a cohort of breast cancer patients and its influence on tamoxifen sensitivity in MCF-7 breast cancer cells in vitro. Publically available gene expression data sets were analysed to identify relationships between BAG-1 mRNA expression and patient outcome. BAG-1 protein expression was assessed using immunohistochemistry in 292 patients with invasive ductal carcinoma and correlated with clinicopathological variables, therapeutic response and disease outcome. BAG-1-overexpressing MCF-7 cells were treated with antioestrogens to assess its effects on cell proliferation. Gene expression data demonstrated a consistent association between high BAG-1 mRNA and improved survival. In ER+ cancer (n=189), a high nuclear BAG-1 expression independently predicted improved outcome for local recurrence (P=0.0464), distant metastases (P=0.0435), death from breast cancer (P=0.009, hazards ratio 0.29, 95% CI: 0.114–0.735) and improved outcome in tamoxifen-treated patients (n=107; P=0.0191). BAG-1 overexpression in MCF-7 cells augmented antioestrogen-induced growth arrest. A high BAG-1 expression predicts improved patient outcome in ER+ breast carcinoma. This may reflect both a better definition of the hormone-responsive phenotype and a concurrent increased sensitivity to tamoxifen.
doi:10.1038/sj.bjc.6604809
PMCID: PMC2634679  PMID: 19066611
breast cancer; prognosis; response marker; BAG-1; tamoxifen sensitivity
4.  Expression of LMO4 and outcome in pancreatic ductal adenocarcinoma 
British Journal of Cancer  2008;98(3):537-541.
Identification of a biomarker of prognosis and response to therapy that can be assessed preoperatively would significantly improve overall outcomes for patients with pancreatic cancer. In this study, patients whose tumours exhibited high LMO4 expression had a significant survival advantage following operative resection, whereas the survival of those patients whose tumours had low or no LMO4 expression was not significantly different when resection was compared with operative biopsy alone.
doi:10.1038/sj.bjc.6604177
PMCID: PMC2243155  PMID: 18231110
LMO4; prognosis; outcome; pancreatic cancer; surgical resection; therapeutic response
5.  Growth factor, steroid, and steroid antagonist regulation of cyclin gene expression associated with changes in T-47D human breast cancer cell cycle progression. 
Molecular and Cellular Biology  1993;13(6):3577-3587.
Cyclins and proto-oncogenes including c-myc have been implicated in eukaryotic cell cycle control. The role of cyclins in steroidal regulation of cell proliferation is unknown, but a role for c-myc has been suggested. This study investigated the relationship between regulation of T-47D breast cancer cell cycle progression, particularly by steroids and their antagonists, and changes in the levels of expression of these genes. Sequential induction of cyclins D1 (early G1 phase), D3, E, A (late G1-early S phase), and B1 (G2 phase) was observed following insulin stimulation of cell cycle progression in serum-free medium. Transient acceleration of G1-phase cells by progestin was also accompanied by rapid induction of cyclin D1, apparent within 2 h. This early induction of cyclin D1 and the ability of delayed administration of antiprogestin to antagonize progestin-induced increases in both cyclin D1 mRNA and the proportion of cells in S phase support a central role for cyclin D1 in mediating the mitogenic response in T-47D cells. Compatible with this hypothesis, antiestrogen treatment reduced the expression of cyclin D1 approximately 8 h before changes in cell cycle phase distribution accompanying growth inhibition. In the absence of progestin, antiprogestin treatment inhibited T-47D cell cycle progression but in contrast did not decrease cyclin D1 expression. Thus, changes in cyclin D1 gene expression are often, but not invariably, associated with changes in the rate of T-47D breast cancer cell cycle progression. However, both antiestrogen and antiprogestin depleted c-myc mRNA by > 80% within 2 h. These data suggest the involvement of both cyclin D1 and c-myc in the steroidal control of breast cancer cell cycle progression.
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PMCID: PMC359827  PMID: 8497271
6.  Progestins both stimulate and inhibit breast cancer cell cycle progression while increasing expression of transforming growth factor alpha, epidermal growth factor receptor, c-fos, and c-myc genes. 
Molecular and Cellular Biology  1991;11(10):5032-5043.
This study documents a biphasic change in the rate of cell cycle progression and proliferation of T-47D human breast cancer cells treated with synthetic progestins, consisting of an initial transient acceleration in transit through G1, followed by cell cycle arrest and growth inhibition. Both components of the response were mediated via the progesterone receptor. The data are consistent with a model in which the action of progestins is to accelerate cells already progressing through G1, which are then arrested early in G1 after completing a round of replication, as are cells initially in other phases of the cell cycle. Such acceleration implies that progestins act on genes or gene products which are rate limiting for cell cycle progression. Increased production of epidermal growth factor and transforming growth factor alpha, putative autocrine growth factors in breast cancer cells, does not appear to account for the initial response to progestins, since although the mRNA abundance for these growth factors is rapidly induced by progestins, cells treated with epidermal growth factor or transforming growth factor alpha did not enter S phase until 5 to 6 h later than those stimulated by progestin. The proto-oncogenes c-fos and c-myc were rapidly but transiently induced by progestin treatment, paralleling the well-known response of these genes to mitogenic signals in other cell types. The progestin antagonist RU 486 inhibited progestin regulation of both cell cycle progression and c-myc expression, suggesting that this proto-oncogene may participate in growth modulation by progestins.
Images
PMCID: PMC361499  PMID: 1922031

Results 1-6 (6)