Effect of tamoxifen on Ki67 labelling index in human breast tumours and its relationship to oestrogen and progesterone receptor status

Antiprogestins for breast cancer treatment: We are almost ready

The development of antiprogestins was initially a gynecological purpose. However, since mifepristone was developed, its application for breast cancer treatment was immediately proposed. Later, new compounds with lower antiglucocorticoid and antiandrogenic effects were developed to be applied to different pathologies, including breast cancer. We describe herein the studies performed in the breast cancer field with special focus on those reported in recent years, ranging from preclinical biological models to those carried out in patients. We highlight the potential use of antiprogestins in breast cancer prevention in women with BRCA1 mutations, and their use for breast cancer treatment, emphasizing the need to elucidate which patients will respond. In this sense, the PR isoform ratio has emerged as a possible tool to predict antiprogestin responsiveness. The effects of combined treatments of antiprogestins together with other drugs currently used in the clinic, such as tamoxifen, CDK4/CDK6 inhibitors or pembrolizumab in preclinical models is discussed since it is in this scenario that antiprogestins will be probably introduced. Finally, we explain how transcriptomic or proteomic studies, that were carried out in different luminal breast cancer models and in breast cancer samples that responded or were predicted to respond to the antiprogestin therapy, show a decrease in proliferative pathways. Deregulated pathways intrinsic of each model are discussed, as well as how these analyses may contribute to a better understanding of the mechanisms involved.

Beneficial Effects of Mifepristone Treatment in Patients with Breast Cancer Selected by the Progesterone Receptor Isoform Ratio: Results from the MIPRA Trial

PURPOSE

Preclinical data suggest that antiprogestins inhibit the growth of luminal breast carcinomas that express higher levels of progesterone receptor isoform A (PRA) than isoform B (PRB). Thus, we designed a presurgical window of opportunity trial to determine the therapeutic effects of mifepristone in patients with breast cancer, based on their high PRA/PRB isoform ratio (MIPRA; NCT02651844).

PATIENTS AND METHODS

Twenty patients with luminal breast carcinomas with PRA/PRB > 1.5 (determined by Western blots), and PR ≥ 50%, naïve from previous treatment, were included for mifepristone treatment (200 mg/day orally; 14 days). Core needle biopsies and surgical samples were formalin fixed for IHC studies, while others were snap-frozen to perform RNA sequencing (RNA-seq), proteomics, and/or Western blot studies. Plasma mifepristone levels were determined using mass spectrometry. The primary endpoint was the comparison of Ki67 expression pretreatment and posttreatment.

RESULTS

A 49.62% decrease in Ki67 staining was observed in all surgical specimens compared with baseline (P = 0.0003). Using the prespecified response parameter (30% relative reduction), we identified 14 of 20 responders. Mifepristone induced an increase in tumor-infiltrating lymphocytes; a decrease in hormone receptor and pSer118ER expression; and an increase in calregulin, p21, p15, and activated caspase 3 expression. RNA-seq and proteomic studies identified downregulated pathways related to cell proliferation and upregulated pathways related to immune bioprocesses and extracellular matrix remodeling.

CONCLUSIONS

Our results support the use of mifepristone in patients with luminal breast cancer with high PRA/PRB ratios. The combined effects of mifepristone and estrogen receptor modulators warrant clinical evaluation to improve endocrine treatment responsiveness in these patients. See related commentary by Ronchi and Brisken, p. 833.

Molecular Biomarker Expression in Window of Opportunity Studies for Oestrogen Receptor Positive Breast Cancer-A Systematic Review of the Literature

Simple Summary

Window of opportunity (WoO) trials allow the opportunity to assess the use of drugs in breast cancer research before treatment has commenced. The aim of this review of the literature is to review WoO trials in patients with oestrogen receptor-positive (ER+) breast cancer to help guide treatment. This will be useful for patients who receive drug treatment before surgery, or as an alternative to surgery in older, more frail adults.

Abstract

Window of opportunity (WoO) trials create the opportunity to demonstrate pharmacodynamic parameters of a drug in vivo and have increasing use in breast cancer research. Most breast cancer tumours are oestrogen receptor-positive (ER+), leading to the development of multiple treatment options tailored towards this particular tumour subtype. The aim of this literature review is to review WoO trials pertaining to the pharmacodynamic activity of drugs available for use in ER+ breast cancer in order to help guide treatment for patients receiving neoadjuvant and primary endocrine therapy. Five databases (EMBASE, Cochrane, MEDLINE, PubMed, Web of Science) were searched for eligible studies. Studies performed in treatment-naïve patients with histologically confirmed ER+ breast cancer were included if they acquired pre- and post-treatment biopsies, compared measurement of a proteomic biomarker between these two biopsies and delivered treatment for a maximum mean duration of 31 days. Fifteen studies were eligible for inclusion and covered six different drug classes: three endocrine therapies (ETs) including aromatase inhibitors (AIs), selective oestrogen receptor modulators (SERMs), selective oestrogen receptor degraders (SERDs) and three non-ETs including mTOR inhibitors, AKT inhibitors and synthetic oestrogens. Ki67 was the most frequently measured marker, appearing in all studies. Progesterone receptor (PR) and ER were the next most frequently measured markers, appearing five and four studies, respectively. All three of these markers were significantly downregulated in both AIs and SERDs; Ki67 alone was downregulated in SERMs. Less commonly assessed markers including pS6, pGSH3B, FSH and IGF1 were downregulated while CD34, pAKT and SHBG were significantly upregulated. There were no significant changes in the other biomarkers measured such as phosphate and tensin homolog (PTEN), Bax and Bcl-2.WoO studies have been widely utilised within the ER+ breast cancer subtype, demonstrating their worth in pharmacodynamic research. However, research remains focused upon routinely measured biomarkers such ER PR and Ki67, with an array of less common markers sporadically used.

The progesterone-receptor modulator, ulipristal acetate, drastically lowers breast cell proliferation

PURPOSE

The proliferation of breast epithelial cells increases during the luteal phase of the menstrual cycle, when they are exposed to progesterone, suggesting that ulipristal acetate, a selective progestin-receptor modulator (SPRM), may reduce breast cell proliferation with potential use in breast cancer chemoprevention.

METHODS

Women aged 18-39 were randomized 1:1 to ulipristal 10-mg daily or to a combination oral contraceptive (COC) for 84 days. Participants underwent a breast biopsy and breast MRI at baseline and at end of study treatment. Proliferation of breast TDLU cells was evaluated by Ki67 immunohistochemical stain. We evaluated the breast MRIs for background parenchymal enhancement (BPE). All slides and images were masked for outcome evaluation.

RESULTS

Twenty-eight treatment-compliant participants completed the study; 25 of whom had evaluable Ki67 results at baseline and on-treatment. From baseline to end of treatment, Ki67 % positivity (Ki67%+) decreased a median of 84% in the ulipristal group (N = 13; 2-sided p (2p) = 0.040) versus a median increase of 8% in the COC group (N = 12; 2p = 0.85). Median BPE scores decreased from 3 to 1 in the ulipristal group (p = 0.008) and did not decrease in the COC group.

CONCLUSION

Ulipristal was associated with a major decrease in Ki67%+ and BPE. Ulipristal would warrant further investigation for breast cancer chemoprevention were it not for concerns about its liver toxicity. Novel SPRMs without liver toxicity could provide a new approach to breast cancer chemoprevention.

TRIAL REGISTRATION

NCT02922127, 4 October 2016.

Practical consensus recommendations regarding the management of hormone receptor positive early breast cancer in elderly women

Breast cancer is a leading cause of death among women, and its incidence increases with age. Currently the treatment of breast cancer in older patients is almost identical to their younger counterparts. This expert group used data from published literature, practical experience and opinion of a large group of academic oncologists to arrive at these practical consensus recommendations for the benefit of community oncologists regarding the management of early breast cancer specifically in elderly women.

Window of opportunity treatment in breast cancer

Window of opportunity therapies, which involve short-term administration of systemic therapy between cancer diagnosis and surgery, have raised significant interest in recent years as a mean of assessing the sensitivity of a patient's cancer to therapy prior to surgery. There is now compelling evidence that in patients with early stage hormone-receptor positive breast cancer, a 2-week preoperative treatment with standard hormone therapies in a preoperative window period provides important prognostic information, which in turn helps to aid decision-making regarding treatment options. Changes in short-term biomarker endpoints such as cell proliferation measured by Ki-67 can act as surrogate markers of long-term outcomes. Paired tissues obtained pre- and post-investigational treatment, without having to subject the patient to additional biopsies, can then be used to conduct translational research to investigate predictive biomarkers and pharmacodynamics. In this review, we will examine the utility and challenges of window of opportunities therapies in breast cancer in the current literature, and the current Australian and international trial landscape in this clinical space.

Streptomyces Levis ABRIINW111 Inhibits SW480 Cells Growth by Apoptosis Induction

Purpose: Streptomyces sp., a dominant genus in Actinomycetes, is the source of a wide variety of secondary metabolites. Microbial metabolites can be utilized as novel anticancer agents; with fewer side effects. The present article illustrated the anti-carcinogenic effect of the ether extracted organic metabolites derived from Streptomyces bacteria on SW480 colon cancer cell line.

Methods: MTT assay was performed in order to investigate the cytotoxicity effect of metabolites on SW480 cells. Apoptosis and cell cycle arrests were measured by flowcytometry. Morphological changes were indicated by Propidium iodide staining andP53 gene expression was evaluated by real-time PCR.

Results: Streptomyces Levis ABRIINW111 inhibited cell growth, increased Caspases 3 and reduced Ki67 expression in a concentration/time-dependent manner in SW40 cells. Metabolites increased subG1 phase (apoptosis) and also cell cycle arrest in G1, G­­­2/M and S phase. P53 gene expression followed Sw480 cells treatment significantly.

Conclusion: Streptomyces sp. metabolites have anti-carcinogenic effect on colon cancer cells. Streptomyces Levis ABRIINW111 metabolites are a candidate for Colon cancer treatment.

IPET study: an FLT-PET window study to assess the activity of the steroid sulfatase inhibitor irosustat in early breast cancer

BACKGROUND

Steroid sulfatase (STS) is involved in oestrogen biosynthesis and irosustat is a first generation, irreversible steroid sulfatase inhibitor. A pre-surgical window-of-opportunity study with irosustat was undertaken in estrogen receptor-positive (ER+) breast cancer to assess the effect of irosustat on tumour cell proliferation as measured by 3'-deoxy-3'-[18F] fluorothymidine uptake measured by PET scanning (FLT-PET) and Ki67.

METHODS

Postmenopausal women with untreated ER+ early breast cancer were recruited, and imaged with FLT-PET at baseline and after at least 2 weeks treatment with irosustat, 40 mg once daily orally. The primary endpoint was changed in FLT uptake; secondary endpoints included safety and tolerability of irosustat, changes in tumoral Ki67 and steroidogenic enzymes expression and circulating steroid hormone levels.

RESULTS

Thirteen women were recruited, and ten started irosustat for 2 weeks, followed by repeat FLT-PET scans in eight. Defining response as decreases of ≥20% in standardized uptake value (SUV) or ≥30% in Ki, 1 (12.5% (95% CI 2-47%, p = 0.001)) and 3 (43% (95% CI 16-75%, p = <0.001) patients, respectively, responded. 6 out of 7 patients had a Ki67 reduction (range = -19.3 to 76.4%), and median percentage difference in Ki67 was 52.3% (p = 0.028). In one patient with a low baseline STS expression, a 19.7% increase in Ki67 was recorded. STS decreases were seen in tumours with high basal STS expression, significant decreases were also noted in aromatase, and 17β-hydroxysteroid dehydrogenase type 1 and 2. Irosustat was generally well tolerated with all adverse event CTCAE Grade ≤2.

CONCLUSIONS

Irosustat resulted in a significant reduction in FLT uptake and Ki67, and is well tolerated. These data are the first demonstrating clinical activity of irosustat in early breast cancer. Baseline expression of STS may be a biomarker of sensitivity to irosustat.

POWERPIINC (PreOperative Window of Endocrine TheRapy Provides Information to Increase Compliance) trial: Changes in tumor proliferation index and quality of life with 7 days of preoperative tamoxifen

OBJECTIVES

A decrease in Ki67 during neoadjuvant therapy predicts response to tamoxifen. Previous trials have shown a decreased Ki67 in breast tumors with as little as two or more weeks of preoperative tamoxifen. Shortening the preoperative treatment time in window of opportunity clinical trials makes these trials more attractive to women. POWERPIINC examined the effect of 7 days of preoperative tamoxifen on breast tumor proliferation and patient symptoms.

METHODS

Women with untreated stage I/II, ER-positive, invasive breast cancer with no contraindications to tamoxifen were enrolled. Women received 20 mg of tamoxifen for 7 days up to the day of surgery. Proliferation was assessed by Ki67 immunohistochemistry before and after 7 days of tamoxifen. Symptoms and QOL were assessed by the FACT-ES and MENQOL. Adherence was measured by pill counts.

RESULTS

52 women were enrolled, and 44 were evaluable for Ki67. The median age was 58.5 years, and the median tumor diameter was 1.2 cm. Most women (73%) were post-menopausal. Most tumors were PR positive (88%) and HER2-negative (92%). The Ki67 decreased by a geometric mean of 40% (95% CI 29%-63%), and 73% (95% CI 57%-85%) of women had tumors with decreased proliferation (p = 0.0001 by paired t-test). Adherence to taking tamoxifen during the preoperative period was 100%. Women reported minimal bother from psychosocial or physical symptoms at baseline or on the day of surgery.

CONCLUSION

Seven days of tamoxifen showed a similar relative decrease in Ki67 as that reported for longer courses, was acceptable to women, and could be considered for window of opportunity studies.

Presurgical window of opportunity trial design as a platform for testing anticancer drugs: Pros, cons and a focus on breast cancer

The high attrition rate is a major issue in anticancer drug development. Among the alternative trial designs, presurgical window of opportunity trials envision a short course treatment in the time window between diagnostic biopsy and surgery in a moderately-sized patient population. This approach allows testing therapeutics when pre- and post-treatment tumor tissues are available for comprehensive molecular analyses. The emerging evidence may help define the ability of a given agent to modulate its target(s) and help obtain a broader picture of the molecular changes operated by the treatment. The resulting gain may outweigh the potential harms for patients in the early disease setting. Window of opportunity trials have been extensively applied to breast cancer. Overall, a wider use of these trial designs might lead to the identification of potential responders, ineffective drugs or combinations, and ultimately contribute to enhance the efficiency of the clinical developmental process.

Tamoxifen impairs prepubertal mammary development and alters expression of estrogen receptor α (ESR1) and progesterone receptors (PGR)

Research has shown that prepubertal heifers experience allometric mammary growth that is influenced by the ovaries. Our purpose was to determine the role of estrogen in prepubertal mammary gland development. Sixteen Holstein calves were randomly assigned to 1 of 2 treatment groups: tamoxifen-injected (TAM) or control (CON). Calves were administered the antiestrogen tamoxifen (0.3 mg kg(1) d(1)) or placebo from 28 to 120 d of age. At 120 d, calves were euthanized and udders removed. Weight and DNA content of trimmed parenchymal tissue were halved (P ≤ 0.0001) in TAM compared with CON calves. Parenchymal samples from 3 zones of the left rear mammary gland (lower, middle, and outer regions) were processed for immunohistochemical staining for estrogen receptor α (ESR1) and progesterone receptor (PGR), Ki67-positive cells, and 5-bromo-2'-deoxyuridine label retaining cells (LRCs). Overall, neither the percentage nor location within the epithelial tissue layer of either ESR1- or PGR-positive cells was impacted by TAM treatment. However, image analysis indicated a 6.2-fold lower (P = 0.0001) level of ESR1 protein expression in TAM calves. Similarly, messenger RNA expression of ESR1 was also reduced (P = 0.0001) in TAM heifers. In contrast, expression of PGR protein was greater by 43% (P = 0.03) in TAM calves, but messenger RNA expression did not differ between treatments. Overall, TAM calves had a higher (P ≤ 0.03) percentage and density (cells per tissue area) of Ki67-positive cells. Irrespective of treatment, there were also more Ki67-labeled cells in the outer zones of the mammary gland (P ≤ 0.001). We were able to effectively use multispectral imaging to identify positive cells and quantify the expression of ESR1 and PGR protein. We also identified and counted the proportion of label retaining cells (LCR) (putative epithelial stem cells). We noted an overall 2.9-fold greater number of LRCs in TAM heifers and more LRCs in the outer sampling zones. This suggests that a cohort of LCR cells in TAM remained inactivated in comparison with CON heifers, which exhibited markedly increased growth of the mammary parenchymal tissue over the treatment period. These results suggest that the impacts of ovariectomy are partially explained by loss of ESR1 expression and/or estrogen receptor signaling in the prepubertal bovine mammary gland. The significance of mammary expression of PGR in control of prepubertal bovine mammary development remains unresolved.

Tamoxifen prevents apoptosis and follicle loss from cyclophosphamide in cultured rat ovaries

Recent studies documented that the selective estrogen receptor modulator tamoxifen prevents follicle loss and promotes fertility following in vivo exposure of rodents to irradiation or ovotoxic cancer drugs, cyclophosphamide and doxorubicin. In an effort to characterize the ovarian-sparing mechanisms of tamoxifen in preantral follicle classes, cultured neonatal rat ovaries (Day 4, Sprague Dawley) were treated for 1-7 days with active metabolites of cyclophosphamide (i.e., 4-hydroxycyclophosphamide; CTX) (0, 1, and 10 μM) and tamoxifen (i.e., 4-hydroxytamoxifen; TAM) (0 and 10 μM) in vitro, and both apoptosis and follicle numbers were measured. CTX caused marked follicular apoptosis and follicular loss. TAM treatment decreased follicular loss and apoptosis from CTX in vitro. TAM alone had no effect on these parameters. IGF-1 and IGF-1 receptor were assessed in ovarian tissue showing no impact of TAM or CTX on these endpoints. Targeted mRNA analysis during follicular rescue by TAM revealed decreased expression of multiple genes related to inflammation, including mediators of lipoxygenase and prostaglandin production and signaling (Alox5, Pla2g1b, Ptgfr), cytokine binding (Il1r1, Il2rg ), apoptosis (Tnfrsf1a), second messenger signaling (Mapk1, Mapk14, Plcg1), as well as tissue remodeling and vasodilation (Bdkrb2, Klk15). The results suggest that TAM protects the ovary from CTX-mediated toxicity through direct ovarian actions that oppose follicular loss.

Evaluating the feasibility of performing window of opportunity trials in breast cancer

BACKGROUND

The waiting period to surgery represents a valuable "window of opportunity" to evaluate novel therapeutic strategies. Interventional studies performed during this period require significant multidisciplinary collaboration to overcome logistical hurdles. We undertook a one-year prospective window of opportunity study to assess feasibility.

METHODS

Eligible newly diagnosed postmenopausal, estrogen receptor positive breast cancer patients awaiting primary surgery received anastrozole daily until surgery. Feasibility was assessed by (a) the proportion of patients who consented and (b) completed the study. Comparison of pre- and poststudy Ki67 labelling index and cleaved caspase 3 scores (CC3) was performed.

RESULTS

22/131 (16.8%) patients were confirmed eligible and 20/22 (91%) patients completed the study. 19/20 (95%) patients agreed to undergo optional additional tissue biopsies. The mean duration of anastrozole use was 24.7 (15-44) days. There were a statistically significant decline in mean Ki67 indices of 48.8% (p < 0.001) and a trend towards significance in the decline of CC3 (p = 0.17) when comparing pre- with posttreatment values.

CONCLUSION

window of opportunity trials in breast cancer are a feasible way of assessing the biologic efficacy of different therapies in the presurgical setting. The majority of eligible women were willing to participate including undergoing additional tissue biopsies.

NEOCENT: a randomised feasibility and translational study comparing neoadjuvant endocrine therapy with chemotherapy in ER-rich postmenopausal primary breast cancer

Neoadjuvant endocrine therapy is an alternative to chemotherapy for women with oestrogen receptor (ER)-positive early breast cancer (BC). We aimed to assess feasibility of recruiting patients to a study comparing chemotherapy versus endocrine therapy in postmenopausal women with ER-rich primary BC, and response as well as translational endpoints were assessed. Patients requiring neoadjuvant therapy were randomised to chemotherapy: 6 × 3-weekly cycles FE₁₀₀C or endocrine therapy: letrozole 2.5 mg, daily for 18-23 weeks. Primary endpoints were recruitment feasibility and tissue collection. Secondary endpoints included clinical, radiological and pathological response rates, quality of life and translational endpoints. 63/80 patients approached were eligible, of those 44 (70, 95% CI 57-81) were randomised. 12 (54.5, 95% CI 32.2-75.6) chemotherapy patients showed radiological objective response compared with 13 (59.1, 95% CI 36.4-79.3) letrozole patients. Compared with baseline, mean Ki-67 levels fell in both groups at days 2-4 and at surgery [fold change: 0.24 (95% CI 0.12-0.51) and 0.24; (95% CI 0.15-0.37), respectively]. Plasma total cfDNA levels rose from baseline to week 8 [fold change: chemotherapy 2.10 (95% CI 1.47-3.00), letrozole 1.47(95% CI 0.98-2.20)], and were maintained at surgery in the chemotherapy group [chemotherapy 2.63; 95% CI 1.56-4.41), letrozole 0.95 (95% CI 0.71-1.26)]. An increase in plasma let-7a miRNA was seen at surgery for patients with objective radiological response to chemotherapy. Recruitment and tissue collection endpoints were met; however, a larger trial was deemed unfeasible due to slow accrual. Both regimens were equally efficacious. Dynamic changes were seen in Ki-67 and circulating biomarkers in both groups with increases in cfDNA and let-7a miRNA persisting until surgery for chemotherapy patients.

Breast cancer: current and future endocrine therapies

Endocrine therapy forms a central modality in the treatment of estrogen receptor positive breast cancer. The routine use of 5 years of adjuvant tamoxifen has improved survival rates for early breast cancer, and more recently has evolved in the postmenopausal setting to include aromatase inhibitors. The optimal duration of adjuvant endocrine therapy remains an active area of clinical study with recent data supporting 10 years rather than 5 years of adjuvant tamoxifen. However, endocrine therapy is limited by the development of resistance, this can occur by a number of possible mechanisms and numerous studies have been performed which combine endocrine therapy with agents that modulate these mechanisms with the aim of preventing or delaying the emergence of resistance. Recent trial data regarding the combination of the mammalian target of rapamycin (mTOR) inhibitor, everolimus with endocrine therapy have resulted in a redefinition of the clinical treatment pathway in the metastatic setting. This review details the current endocrine therapy utilized in both early and advanced disease, as well as exploring potential new targets which modulate pathways of resistance, as well as agents which aim to modulate adrenal derived steroidogenic hormones.

A randomized phase II presurgical trial of weekly low-dose tamoxifen versus raloxifene versus placebo in premenopausal women with estrogen receptor-positive breast cancer

Introduction

We previously demonstrated that 1 or 5 mg per day of tamoxifen (T) given for four weeks before surgery reduces Ki-67 in breast cancer (BC) patients to the same extent as the standard 20 mg/d. Given the long half-life of T, a weekly dose (10 mg per week (w)) may be worth testing. Also, raloxifene (R) has shown Ki-67 reduction in postmenopausal patients in a preoperative setting, but data in premenopausal women are limited. We conducted a randomized trial testing T 10 mg/w vs. R 60 mg/d vs. placebo in a presurgical model.

Methods

Out of 204 screened subjects, 57 were not eligible, 22 refused to participate and 125 were included in the study. The participants were all premenopausal women with estrogen receptor-positive BC. They were randomly assigned to either T 10mg/w or R 60 mg/d or placebo for six weeks before surgery. The primary endpoint was tissue change of Ki-67. Secondary endpoints were modulation of estrogen and progesterone receptors and several other circulating biomarkers.

Results

Ki-67 was not significantly modulated by either treatment. In contrast, both selective estrogen receptor modulators (SERMs) significantly modulated circulating IGF-I/IGFBP-3 ratio, cholesterol, fibrinogen and antithrombin III. Estradiol was increased with both SERMs. Within the tamoxifen arm, CYP2D6 polymorphism analysis showed a higher concentration of N-desTamoxifen, one of the tamoxifen metabolites, in subjects with reduced CYP2D6 activity. Moreover, a reduction of Ki-67 and a marked increase of sex hormone-binding globulin (SHBG) were observed in the active phenotype.

Conclusions

A weekly dose of tamoxifen and a standard dose of raloxifene did not inhibit tumor cell proliferation, measured as Ki-67 expression, in premenopausal BC patients. However, in the tamoxifen arm women with an extensive phenotype for CYP2D6 reached a significant Ki-67 modulation.

Tocotrienols promote apoptosis in human breast cancer cells by inducing poly(ADP-ribose) polymerase cleavage and inhibiting nuclear factor kappa-B activity

OBJECTIVES

Tocotrienols and tocopherols are members of the vitamin E family, with similar structures; however, only tocotrienols have been reported to achieve potent anti-cancer effects. The study described here has evaluated anti-cancer activity of vitamin E to elucidate mechanisms of cell death, using human breast cancer cells.

MATERIALS AND METHODS

Anti-cancer activity of a tocotrienol-rich fraction (TRF) and a tocotrienol-enriched fraction (TEF) isolated from palm oil, as well as pure vitamin E analogues (α-tocopherol, α-, δ- and γ-tocotrienols) were studied using highly aggressive triple negative MDA-MB-231 cells and oestrogen-dependent MCF-7 cells, both of human breast cancer cell lines. Cell population growth was evaluated using a Coulter particle counter. Cell death mechanism, poly(ADP-ribose) polymerase cleavage and levels of NF-κB were determined using commercial ELISA kits.

RESULTS

Tocotrienols exerted potent anti-proliferative effects on both types of cell by inducing apoptosis, the underlying mechanism of cell death being ascertained using respective IC50 concentrations of all test compounds. There was marked induction of apoptosis in both cell lines by tocotrienols compared to treatment with Paclitaxel, which was used as positive control. This activity was found to be associated with cleavage of poly(ADP-ribose) polymerase (a DNA repair protein), demonstrating involvement of the apoptotic cell death signalling pathway. Tocotrienols also inhibited expression of nuclear factor kappa-B (NF-κB), which in turn can increase sensitivity of cancer cells to apoptosis.

CONCLUSION

Tocotrienols induced anti-proliferative and apoptotic effects in association with DNA fragmentation, poly(ADP-ribose) polymerase cleavage and NF-κB inhibition in the two human breast cancer cell lines.

Assessment of RNA in human breast tissue sampled by random periareolar fine needle aspiration and ductal lavage and processed as fixed or frozen specimens

Ductal lavage (DL) and random periareolar fine needle aspiration (RPFNA) have both been proposed as minimally invasive techniques to sample breast tissue during breast cancer prevention trials. Laser capture microdissection (LCM), linear RNA amplification and quantitative real-time polymerase chain reaction (qPCR) theoretically overcome the limitations of small specimen size obtained with DL and RPFNA. In order to test the yield, relative stability and amplifiability of RNA from fixed and archived RPFNA and DL specimens, breast tissue was sampled from individual high risk women (n=9) by both DL and RPFNA. RPFNA samples showed good RNA/cDNA yield and amplification while only 2 of 9 of the paired DL specimens had cDNA of adequate quality for subsequent PCR. One and two rounds of linear amplification provided approximately a 200- and 20,000-fold enrichment of RNA, respectively. PCR analysis consistently detected ER and COX-1 mRNA in the majority of RPFNA samples examined while pS2, PCNA, VEGF and survivin expression varied with subject. RNA yield and/or stability was greater for fixed and archived RPFNA than DL specimens of breast tissue. In a subsequent study examining an expanded biomarker gene panel in fixed vs. frozen RPFNA samples, mRNA profiles and ranked relative mRNA abundance were similar (r=0.89) for frozen and fixed RPFNA specimens. In summary, frozen RPFNA samples may be optimal for RNA endpoints in human breast cancer prevention trials but fixed RPFNA specimens allow similar analyses with greater convenience.

The omega-3 polyunsaturated fatty acid eicosapentaenoic acid inhibits mouse MC-26 colorectal cancer cell liver metastasis via inhibition of PGE2-dependent cell motility

BACKGROUND AND PURPOSE

The omega-3 polyunsaturated fatty acid (PUFA) eicosapentaenoic acid (EPA) has antineoplastic activity at early stages of colorectal carcinogenesis, relevant to chemoprevention of colorectal cancer (CRC). We tested the hypothesis that EPA also has anti-CRC activity at later stages of colorectal carcinogenesis, relevant to treatment of metastatic CRC, via modulation of E-type PG synthesis.

EXPERIMENTAL APPROACH

A BALB/c mouse model, in which intrasplenic injection of syngeneic MC-26 mouse CRC cells leads to development of liver metastases, was used. Dietary EPA was administered in the free fatty acid (FFA) form for 2 weeks before and after ultrasound-guided intrasplenic injection of 1 × 10(6) MC-26 cells (n= 16 each group).

KEY RESULTS

Treatment with 5% (w w(-1)) EPA-FFA was associated with a reduced MC-26 mouse CRC cell liver tumour burden compared with control animals (median liver weight 1.03 g vs. 1.62 g; P < 0.034). Administration of 5% EPA-FFA was also linked to a significant increase in tumour EPA incorporation and lower intratumoural PGE(2) levels (with concomitant increased production of PGE(3)). Liver tumours from 5% EPA-FFA- treated mice demonstrated decreased 5-bromo-2-deoxyuridine-positive CRC cell proliferation and reduced phosphorylated ERK 1/2 expression at the invasive edge of tumours. A concentration-dependent reduction in MC-26 CRC cell Transwell® migration following EPA-FFA treatment (50-200 µM) in vitro was rescued by exogenous PGE(2) (10 µM) and PGE(1)-alcohol (1 µM).

CONCLUSIONS AND IMPLICATIONS

EPA-FFA inhibits MC-26 CRC cell liver metastasis. EPA incorporation is associated with a 'PGE(2) to PGE(3) switch' in liver tumours. Inhibition of PGE(2)-EP(4) receptor-dependent CRC cell motility probably contributes to the antineoplastic activity of EPA.

Ki-67 biomarker in breast cancer of Indian women

Background:

Biological markers that reliably predict clinical or pathological response to primary systemic therapy early during a course of chemotherapy may have considerable clinical potential.

Aims:

Aims of study to evaluated changes in Ki-67 (MIB-1) labeling index and apoptotic index (AI) before, during, and after neoadjuvant anthracycline chemotherapy in breast cancer in Indian women.

Materials and Methods:

Breast cancer tissues were collected from Grant Medical College and Sir J.J. Group of Hospitals, Mumbai, India. Twenty-seven patients receiving neoadjuvant FEC (5-fluorouracil, epirubicin, and cyclophosphamide) chemotherapy for operable breast cancer underwent repeat core biopsy after 21 days of treatment.

Results:

The objective clinical response rate was 56%. Eight patients (31%) achieved a pathological response by histopathological criteria; two patients had a near-complete pathological response. Increased day-21 AI was a statistically significant predictor of pathological response (p = 0.049). A strong trend for predicting pathological response was seen with higher Ki-67 indices at day 21 and AI at surgery (p = 0.06 and 0.06, respectively).

Conclusion:

The clinical utility of early changes in biological marker expression during chemotherapy remains unclear. Until further prospectively validated evidence confirming the reliability of predictive biomarkers is available, clinical decision-making should not be based upon individual biological tumor biomarker profiles.

Differentially expressed genes in window trials are influenced by the wound-healing process: lessons learned from a pilot study with anastrozole

BACKGROUND

Perioperative window trials provide an opportunity to obtain intact tumor samples at two different time-points for evaluation of potential surrogate biomarkers. We report results of a pilot trial designed to determine if treatment-mediated changes in gene expression can be detected in formalin-fixed paraffin-embedded (FFPE) samples after 10-d exposure to anastrozole in estrogen receptor (ER)-positive breast cancer compared with untreated controls.

METHODS

Paired tumor samples (biopsy, surgical) were obtained from 26 postmenopausal women with ER-positive breast cancer. Patients were assigned anastrozole (1 mg/d) for 10 d immediately prior to surgery (13 cases) or no treatment (13 controls). Five hundred two cancer-related genes were examined by the Illumina cDNA-mediated annealing, selection, extension, and ligation, FFPE cDNA array (moderated t-test, P ≤ 0.005). Surrogate biomarkers reflecting changes in gene expression were examined by immunohistochemistry (Wilcoxon rank-based test, P < 0.05).

RESULTS

Sufficient RNA was available from 19 paired samples (8 controls, 11 cases). Frozen tissue and FFPE showed good correlation (r = 0.82). Within each group, 18 genes, reflecting roles in proliferation, angiogenesis, and apoptosis, showed differential expression from biopsy to surgery (P < 0.005). Estrogen-related genes were dysregulated in the treated group only. A reduction in Ki-67 was observed in 7 (54%) treated cases and in 1 (7.7%) control patient.

CONCLUSIONS

10-d exposure to anastrozole resulted in dysregulation of 18/502 cancer-related genes, and Ki-67 was reduced in 54% of cases. FFPE samples demonstrated good correlation with frozen samples. However, changes in gene expression and increased Ki-67 in the control group suggest local effects of wound healing may represent a confounding factor in the interpretation of perioperative window trials.

The effect of raloxifene on Bax protein expression in breast carcinomas of postmenopausal women

The actual role of Bax protein as a prognostic biomarker that predicts response to therapy remains unclear. The objective of this study was to evaluate the effect of raloxifene on Bax protein expression in breast carcinomas of postmenopausal women. Twenty postmenopausal patients with operable stage II, estrogen receptor-positive, infiltrating ductal breast carcinoma were treated with oral raloxifene at a dose of 60 mg/day for a period of 28 days before definitive surgery. Tumor samples were obtained by incisional biopsy at the time of diagnosis and again at the time of definitive surgical treatment. Immunohistochemical evaluation of Bax expression was assessed semiquantitatively based on the fraction of stained tumor cells and intensity of staining. McNemar's test was used to analyze data (P < 0.05). Eleven of the 20 (55%) patients were classified as positive for Bax expression before raloxifene treatment, whereas 9(45%) were classified as positive after raloxifene treatment (P = 0.479). In conclusion, raloxifene did not alter Bax expression significantly in estrogen receptor-positive breast carcinomas of postmenopausal women.

Evaluation of Ki-67 and Bcl-2 antigen expression in breast carcinomas of women treated with raloxifene

OBJECTIVES

To evaluate the effect of raloxifene on Ki-67 and Bcl-2 antigen expression in operable, stage II, oestrogen-receptor-positive invasive ductal breast carcinomas.

MATERIALS AND METHODS

Twenty post-menopausal women who had taken 60 mg of raloxifene daily for 28 days prior to definitive surgery were enrolled in the investigation. Two tumour samples were obtained by incisional biopsy during the study, one at the time of confirmation of diagnosis of invasive ductal carcinoma and evaluation of oestrogen receptor status, and the other 29 days later, at the time of definitive surgery. Immunohistochemistry was performed on tumour samples, prior to and after raloxifene treatment, to evaluate Ki-67 and Bcl-2 expression. Friedman and McNemar tests were used for statistical analysis of the data, significance being established at 5%.

RESULTS

Mean percentage of Ki-67-stained nuclei was 24.86 +/- 2.95 prior to raloxifene treatment and 13.33 +/- 1.52 after treatment (P < 0.001). Prior to raloxifene treatment, only 9/20 cases (45%) were classified as Bcl-2-positive, whereas after treatment, 17/20 (85%) were classified as Bcl-2-positive (P < 0.013).

CONCLUSIONS

Raloxifene treatment significantly reduced Ki-67 antigen expression and increased Bcl-2 expression in breast carcinomas of post-menopausal women.

Combinational treatment of gap junctional activator and tamoxifen in breast cancer cells

Tamoxifen is a drug of choice for endocrine-responsive breast tumor patients. However, tamoxifen resistance has become a major concern for the treatment of breast cancer. Combinational therapies of tamoxifen and different drugs are being frequently studied. In this study, we tested the efficacy of substituted quinolines (code name=PQ1; a gap junctional activator) in combination with tamoxifen in T47D cells. Colony growth assay was performed using soft agar to measure the colony growth, whereas cell proliferation was measured by the MTT assay in T47D cells. The level of Ki67, survivin, and BAX was measured using confocal microscopy along with western blot analysis. Apoptosis-bromodeoxyuridine triphosphate labeling was also examined in the induced treatment of T47D cells. We observed a 55% decrease in the colony growth in the presence of combination of PQ1 and tamoxifen, whereas tamoxifen alone had little effect. A combination of 10 micromol/l tamoxifen and 200 or 500 nmol/l PQ1 resulted in only 16% cell viability compared with controls at 48 h in T47D cells by the MTT assay. We found a significant increase in BAX protein at 1 h in the presence of 500 nmol/l PQ1 alone, 10 micromol/l tamoxifen alone, and the combination of PQ1 and tamoxifen. A two-fold increase was observed in active caspase 3 in the presence of combinational treatment of 10 micromol/l tamoxifen and 200 or 500 nmol/l PQ1. In addition, flow cytometric analysis showed a 50% increase in the number of apoptotic cells in the presence of the combination of tamoxifen and PQ1 compared with the control. Furthermore, the results show that combinational treatment of tamoxifen and PQ1 significantly reduces the expression of survivin in T47D cells. Gap junction inhibitor studies with carbenexolone were also performed confirming the role of gap junctions in cell proliferation and cell death. The combinational treatment of PQ1 and tamoxifen has a significant increase in BAX expression, caspase 3 activation, and DNA fragmentation. Tamoxifen alone and in combination with PQ1 showed a decrease in the expression of survivin, whereas PQ1 alone was shown to be independent of the survivin-mediated pathway. This suggests that an increase in gap junction activity can potentiate the effect of tamoxifen. The combinational treatment of tamoxifen and PQ1 also showed a significant decrease in cell viability compared with tamoxifen treatment alone. The gap junction inhibitor carbenexolone was shown to increase cell proliferation by increased cyclin D1 expression, MTT assay, and Ki67 expression. It further decreased cell death. This study shows for the first time that combinational treatment of tamoxifen and PQ1 (a gap junctional activator) can be used to potentiate apoptosis of T47D human breast cancer cells. Thus, a gap junctional activator, PQ1, could potentially alter either the length or dose of tamoxifen clinically used for breast cancer patients.

Pathologic and biologic response to preoperative endocrine therapy in patients with ER-positive ductal carcinoma in situ

Background

Endocrine therapy is commonly recommended in the adjuvant setting for patients as treatment for ductal carcinoma in situ (DCIS). However, it is unknown whether a neoadjuvant (preoperative) anti-estrogen approach to DCIS results in any biological change. This study was undertaken to investigate the pathologic and biomarker changes in DCIS following neoadjuvant endocrine therapy compared to a group of patients who did not undergo preoperative anti-estrogenic treatment to determine whether such treatment results in detectable histologic alterations.

Methods

Patients (n = 23) diagnosed with ER-positive pure DCIS by stereotactic core biopsy were enrolled in a trial of neoadjuvant anti-estrogen therapy followed by definitive excision. Patients on hormone replacement therapy, with palpable masses, or with histologic or clinical suspicion of invasion were excluded. Premenopausal women were treated with tamoxifen and postmenopausal women were treated with letrozole. Pathologic markers of proliferation, inflammation, and apoptosis were evaluated at baseline and at three months.

Biomarker changes were compared to a cohort of patients who had not received preoperative treatment.

Results

Median age of the cohort was 53 years (range 38–78); 14 were premenopausal. Following treatment, predominant morphologic changes included increased multinucleated histiocytes and degenerated cells, decreased duct extension, and prominent periductal fibrosis. Two postmenopausal patients had ADH only with no residual DCIS at excision. Postmenopausal women on letrozole had significant reduction of PR, and Ki67 as well as increase in CD68-positive cells. For premenopausal women on tamoxifen treatment, the only significant change was increase in CD68. No change in cleaved caspase 3 was found. Two patients had invasive cancer at surgery.

Conclusion

Preoperative therapy for DCIS is associated with significant pathologic alterations. These changes may be clinically significant. Further work is needed to identify which women may be the best candidates for such treatment for DCIS, and whether best responders may safely avoid surgical intervention.

Trial Registration

ClinicalTrials.gov NCT00290745

Regulation of estrogen receptor alpha by the SET7 lysine methyltransferase

Estrogen receptor alpha (ER) is a ligand-dependent transcription factor. Upon binding estrogen, ER recruits coactivator complexes with histone acetyltransferase or methyltransferase activities to activate downstream target genes. In addition to histones, coactivators can modify ER itself and other proteins in the transactivation complex. Here, we show that ER is directly methylated at lysine 302 (K302) by the SET7 methyltransferase. SET7-mediated methylation stabilizes ER and is necessary for the efficient recruitment of ER to its target genes and for their transactivation. The SET7-ER complex structure reveals the molecular basis for ER peptide recognition and predicts that modifications or mutations of nearby residues would affect K302 methylation. Indeed, a breast cancer-associated mutation at K303 (K303R) alters methylation at K302 in vitro and in vivo. These findings raise the possibility that generation, recognition, and removal of modifications within the ER hinge region generate "ER modification cassettes" that yield distinct patterns for signaling downstream events.

Pre-clinical validation of early molecular markers of sensitivity to aromatase inhibitors in a mouse model of post-menopausal hormone-sensitive breast cancer

INTRODUCTION

Changes in breast cancer cell biology following hormonal treatment have been claimed as promising predictor markers of clinical benefit even outperforming clinical response. From previous work we selected 10 genes showing both a well known regulation by oestrogen and a high level of early transcriptional regulation following therapy with aromatase inhibitors. Here we use an animal breast cancer model to explore the feasibility of the determination of their expression in minimally invasive samples and to further assess the magnitude of their regulation by letrozole. ANIMAL AND METHODS: Aromatase inhibitor sensitive breast cancer tumours were grown in athymic mice under supplement with androstenedione. Following initial tumour growth animals were assigned to a control group or to receive letrozole at two different dosages. Fine needle aspirates were obtained at the moment of treatment assignation and one week later. Expression of the following genes at both time points was determined: Ki-67, Cyclin D1, pS2, Trefoil Factor 3, PDZ domain containing 1, Ubiquitin-conjugating enzyme E2C, Stanniocalcin 2, Topoisomerase 2 alfa, MAN1A1 and FAS.

RESULTS

Fine needles aspirates were found to be a feasible and reproducible technique for RNA extraction. Trefoil Factor 3, pS2, Cyclin D1 and Stanniocalcin 2 were significantly downregulated by letrozole. Among them pS2 appears to be most sensitive to aromatase inhibitor treatment even differentiating sub-optimal from optimal letrozole dosage.

DISCUSSION

We present pre-clinical evidence to justify the exploration in clinical trials of pS2, Trefoil factor 3, Cyclin D1 and Stanniocalcin as dynamic markers of oestrogen-driven pathway activation.

Evaluation of the effect of paclitaxel, epirubicin and tamoxifen by cell kinetics parameters in estrogen-receptor-positive ehrlich ascites tumor (eat) cells growing in vitro

In this study the antiproliferative effects of Paclitaxel (PAC), Epirubicin (EPI) and Tamoxifen (TAM) on growth kinetics of Ehrlich Ascites Tumor (EAT) cells were examined in culture. An estrogen-receptor-positive ER (+) hyperdiploid EAT cell line growing in vitro was also analysed in the present study. IC50 doses of PAC, EPI and TAM (12 microg/ml, 12 microg/ml and 2 microg/ml, respectively) were used. Cells were treated with the above doses for 0, 4, 8, 16, 24 and 32 hrs. At the end of these periods, living cell numbers were determined by collecting EAT cells in every group for growth study rate and for MTT assay. Therefore, the mitotic index was determined in the same experimental groups. The proliferation of EAT cells, inhibited by PAC, EPI and TAM concentrations was compared to control with increasing treatment time (4-32 hrs). Treatment of PAC, EPI and TAM alone for 24 hrs decreased the proliferation rate of EAT cells by 50% with respect to control. The inhibition of proliferation rate was higher in double drug treatment than that in single drug treatment with increased treatment time. In the treatment of three drugs applied for 32 hrs, this effect reached a maximum and proliferation rate decreased by 12% as compared to the (100%) control. In our studies, when the mitotic index parameter data were evaluated to determine which phase of the cell cycle was affected by PAC to cause the repression of cell reproduction, it was found that PAC exerted of its cytotoxic effect by causing cell accumulation at mitosis. The accumulation of the cells resulted in an increase in mitotic index values, which was an expected consequence of PAC treatment. It was observed that depending on the drug treatments, inhibition of proliferation rate and mitotic index in EAT cells were increased with respect to control, being with statistically significant occurrence (p < 0.01 - p < 0.001). As a result, concomitant treatment combined with hormonal therapy has given improved results compared with single treatment and PAC + EPI + TAM treatments had a maximum synergistic effect for 32 hrs (p < 0.001).

Identification of novel proteins induced by estradiol, 4-hydroxytamoxifen and acolbifene in T47D breast cancer cells

Tamoxifen is currently used as adjuvant therapy for estrogen receptor (ER) positive breast cancer patients and as a chemopreventative agent. Although ER is a predictive marker for tamoxifen response, ER status fails to predict tamoxifen response in a significant number of patients highlighting the need to identify new pathways for tamoxifen sensitivity/resistance. To identify novel proteins induced by tamoxifen in breast cancer cells sensitive to tamoxifen growth inhibition, two-dimensional (2D) gel electrophoresis was used to profile proteins in T47D breast cancer cells. Six proteins were identified that were differentially regulated by 17beta-estradiol, 4-hydroxytamoxifen and the pure antagonist acolbifene (EM-652); calreticulin, synapse associated protein 1 (SYAP1), CD2 antigen binding protein 2 (CD2BP2), nucleosome assembly protein 1 like 1 (NAP1L1), d-3-phosphoglycerate dehydrogenase (3-PHGDH) and pyridoxine 5' phosphate oxidase (PNPO). At the mRNA level, these ligands differentially regulated expression of mRNAs encoding the identified proteins in T47D and MCF7 cells but had no effect on mRNA in ERalpha-negative MDA-MB-231 breast cancer cells. These novel SERM-regulated proteins may participate in new or existing pathways for sensitivity or resistance to SERMs.

Evaluation of Ki-67 proliferation and apoptotic index before, during and after neoadjuvant chemotherapy for primary breast cancer

INTRODUCTION

Biological markers that reliably predict clinical or pathological response to primary systemic therapy early during a course of chemotherapy may have considerable clinical potential. This study evaluated changes in Ki-67 labeling index and apoptotic index (AI) before, during, and after neoadjuvant anthracycline chemotherapy.

METHODS

Twenty-seven patients receiving neoadjuvant FEC (5-fluorouracil, epirubicin, and cyclophosphamide) chemotherapy for operable breast cancer underwent repeat core biopsy after 21 days of treatment. Tissue from pre-treatment biopsy, day 21 and surgery was analysed for Ki-67 index and AI.

RESULTS

The objective clinical response rate was 56%. Eight patients (31%) achieved a pathological response by histological criteria; two patients had a near-complete pathological response. A reduction in Ki-67 index was observed in 68% of patients at day 21 and 72% at surgery; Ki-67 index increased between day 21 and surgery in 54%. AI decreased in 50% of tumours by day 21, increased in 45% and was unchanged in one patient; 56% demonstrated rebound increases in AI by the time of surgery. Neither pre-treatment nor post-chemotherapy median Ki-67 index nor median AI at all three time points or relative changes at day 21 and surgery differed significantly between clinical or pathological responders and non-responders. Clinical responders had lower median Ki-67 indices at day 21 (11.4% versus 27.0%, p = 0.02) and significantly greater percentage reductions in Ki-67 at day 21 than did non-responders (-50.6% versus -5.3%, p = 0.04). The median day-21 Ki-67 was higher in pathological responders (30.3% versus 14.1%, p = 0.046). A trend toward increased AI at day 21 in pathological responders was observed (5.30 versus 1.68, p = 0.12). Increased day-21 AI was a statistically significant predictor of pathological response (p = 0.049). A strong trend for predicting pathological response was seen with higher Ki-67 indices at day 21 and AI at surgery (p = 0.06 and 0.06, respectively).

CONCLUSION

The clinical utility of early changes in biological marker expression during chemotherapy remains unclear. Until further prospectively validated evidence confirming the reliability of predictive markers is available, clinical decision-making should not be based upon individual biological tumour marker profiles.

Attenuation of estrogen receptor alpha (ERalpha) signaling by selenium in breast cancer cells via downregulation of ERalpha gene expression

Numerous studies have shown that selenium provides beneficial effects as a cancer chemoprevention agent. Although long-term intervention trials failed to confirm selenium protection against breast cancer in humans because of insufficient cases, the evidence of effective selenium chemoprevention in animal mammary tumor models or human breast cancer cells is substantial and convincing. The present study demonstrates that the selenium compound methylseleninic acid (MSA) inhibits estrogen receptor alpha (ERalpha) signaling in ER-positive MCF-7 breast cancer cells as evidenced by decreased estradiol-dependent cell growth and gene expression. MSA diminishes estradiol induction of endogenous ER-regulated pS2 and c-myc genes as well as the expression of an ER-regulated reporter gene. A major mode of MSA action on ER signaling is through a downregulation of ERalpha gene expression that precedes a decrease in ERalpha protein level. This study provides a mechanism driven rationale for using selenium as a chemopreventive agent for women at high risk for developing breast cancer or as a therapeutic strategy for ER-positive breast cancer.

Proliferation marker Ki-67 in early breast cancer

Molecular markers have been extensively investigated with a view to providing early and accurate information on long-term outcome and prediction of response to treatment of early breast cancer. Proliferation is a key feature of the progression of tumors and is now widely estimated by the immunohistochemical assessment of the nuclear antigen Ki-67. The expression of Ki-67 correlates with other measurements of proliferation, including S-phase and bromodeoxyuridine uptake. High Ki-67 is a sign of poor prognosis associated with a good chance of clinical response to chemotherapy, but its independent significance is modest and does not merit measurements in most routine clinical scenarios. However, its application as a pharmacodynamic intermediate marker of the effectiveness of medical therapy holds great promise for rapid evaluation of new drugs.

Dietary flaxseed alters tumor biological markers in postmenopausal breast cancer

PURPOSE

Flaxseed, the richest source of mammalian lignan precursors, has previously been shown to reduce the growth of tumors in rats. This study examined, in a randomized double-blind placebo-controlled clinical trial, the effects of dietary flaxseed on tumor biological markers and urinary lignan excretion in postmenopausal patients with newly diagnosed breast cancer.

EXPERIMENTAL DESIGN

Patients were randomized to daily intake of either a 25 g flaxseed-containing muffin (n = 19) or a control (placebo) muffin (n = 13). At the time of diagnosis and again at definitive surgery, tumor tissue was analyzed for the rate of tumor cell proliferation (Ki-67 labeling index, primary end point), apoptosis, c-erbB2 expression, and estrogen and progesterone receptor levels. Twenty-four-hour urine samples were analyzed for lignans, and 3-day diet records were evaluated for macronutrient and caloric intake. Mean treatment times were 39 and 32 days in the placebo and flaxseed groups, respectively.

RESULTS

Reductions in Ki-67 labeling index (34.2%; P = 0.001) and in c-erbB2 expression (71.0%; P = 0.003) and an increase in apoptosis (30.7%; P = 0.007) were observed in the flaxseed, but not in the placebo group. No significant differences in caloric and macronutrient intake were seen between groups and between pre- and posttreatment periods. A significant increase in mean urinary lignan excretion was observed in the flaxseed group (1,300%; P < 0.01) compared with placebo controls. The total intake of flaxseed was correlated with changes in c-erbB2 score (r = -0.373; P = 0.036) and apoptotic index (r = 0.495; P < 0.004).

CONCLUSION

Dietary flaxseed has the potential to reduce tumor growth in patients with breast cancer.

Biomarker Changes During Neoadjuvant Anastrozole, Tamoxifen, or the Combination: Influence of Hormonal Status and HER-2 in Breast Cancer—A Study from the IMPACT Trialists

Purpose

To investigate the relationships between biomarker changes in breast cancer during neoadjuvant (preoperative) endocrine therapy.

Patients and Methods

The IMPACT trial compared the preoperative use of tamoxifen with anastrozole alone or in combination in postmenopausal women (n = 330) with primary breast cancer. Biomarkers were measured in tumor biopsy specimens taken at baseline, and after 2 and 12 weeks of treatment.

Results

A decrease in the proliferation marker Ki67 occurred in the majority of patients: 52 (93%) of 56, 46 (85%) of 54, and 37 (84%) of 44 patients in the anastrozole, tamoxifen, and combination groups, respectively. There was a significantly greater suppression of Ki67 in the anastrozole-treated group than in the tamoxifen- or combination-treated groups, which is parallel to the greater efficacy seen for anastrozole over these two treatments in the Arimidex, Tamoxifen, Alone or in Combination adjuvant trial. A positive relationship was noted between estrogen-receptor level and Ki67 suppression in all patients. Ki67 was reduced to a greater extent in progesterone receptor-positive tumors compared with progesterone receptor-negative tumors. HER-2-negative tumors tended to show a greater reduction in Ki67 compared with HER-2-positive tumors, but the difference was only significant in the tamoxifen group after 2 weeks, and in the anastrozole group after 12 weeks.

Conclusion

These results confirm the value of Ki67 as a molecular marker, and provide information regarding the relationships between treatment-induced changes in Ki67 and other important biomarkers. Studies such as this should help integrate agents targeted at growth factor signaling with endocrine agents in breast cancer.

Evaluation of ER, PgR, HER-2 and Ki-67 as predictors of response to neoadjuvant anthracycline chemotherapy for operable breast cancer

Primary systemic therapy (PST) for operable breast cancer enables the identification of in vivo biological markers that predict response to treatment. A total of 118 patients with T2–4 N0–1 M0 primary breast cancer received six cycles of anthracycline-based PST. Clinical and radiological response was assessed before and after treatment using UICC criteria. A grading system to score pathological response was devised. Diagnostic biopsies and postchemotherapy surgical specimens were stained for oestrogen (ER) and progesterone (PgR) receptor, HER-2 and cell proliferation (Ki-67). Clinical, radiological and pathological response rates were 78, 72 and 38%, respectively. There was a strong correlation between ER and PgR staining (P<0.0001). Higher Ki-67 proliferation indices were associated with PgR− tumours (median 28.3%, PgR+ 22.9%; P=0.042). There was no relationship between HER-2 and other biological markers. No single pretreatment or postchemotherapy biological parameter predicted response by any modality of assessment. In all, 10 tumours changed hormone receptor classification after chemotherapy (three ER, seven PgR); HER-2 staining changed in nine cases. Median Ki-67 index was 24.9% before and 18.1% after treatment (P=0.02); the median reduction in Ki-67 index after treatment was 21.2%. Tumours displaying >75% reduction in Ki-67 after chemotherapy were more likely to achieve a pathological response (77.8 vs 26.7%, P=0.004).

Short-Term Changes in Ki-67 during Neoadjuvant Treatment of Primary Breast Cancer with Anastrozole or Tamoxifen Alone or Combined Correlate with Recurrence-Free Survival

Purpose: Neoadjuvant (preoperative) therapy for breast cancer may allow for the development of intermediate markers of treatment benefit, thereby circumventing the need for efficacy trials of adjuvant therapy, which require much larger patient numbers and longer follow-up. The aim of this study—as part of the Immediate Preoperative “Arimidex” (anastrozole), Tamoxifen, or Arimidex Combined with Tamoxifen (IMPACT) trial (n = 330)—was to test the hypotheses that changes in Ki-67 after 2 weeks and/or 12 weeks: (i) differed between treatments, (ii) predicted clinical tumor response, and/or (iii) may predict long-term outcome differences between treatments in adjuvant therapy.

Experimental Design: The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial compared these same agents in the adjuvant setting. Biomarkers were measured in biopsy specimens taken before and after 2 and 12 weeks of treatment.

Results: Suppression of the proliferation marker Ki-67 after 2 and 12 weeks was significantly greater with anastrozole than with tamoxifen (P = 0.004 and P &lt; 0.001) but was similar between tamoxifen and the combination (P = 0.600 and P = 0.912). This result closely parallels that seen for the relative recurrence-free survival with the treatments after a median follow-up of 31 months in the ATAC trial in 9,366 patients. Against expectations, apoptosis was not increased in any of the treatment arms.

Conclusions: The data indicate that short-term changes in proliferation in the neoadjuvant setting may be able to predict outcome during adjuvant use of the same treatments. If this can be confirmed, these findings could lead to a profound change in approaches to drug development in breast cancer. The data indicate that estrogen is not an important survival factor for human breast cancer cells.

Postmenopausal testosterone therapy and breast cancer risk

BACKGROUND

Testosterone therapy is being increasingly used in the management of postmenopausal women. However, as clinical trials have demonstrated a significantly increased risk of breast cancer with oral combined estrogen-progestin therapy, there is a need to ascertain the risk of including testosterone in such regimens.

OBJECTIVE

Evaluation of experimental and epidemiological studies pertaining to the role of testosterone in breast cancer.

DESIGN

Literature review.

SETTING

The Jean Hailes Foundation, Research Unit.

MAIN OUTCOME MEASURES

Mammary epithelial proliferation, apoptosis and breast cancer.

RESULTS

In experimental studies, testosterone action is anti-proliferative and pro-apoptotic, and mediated via the AR, despite the potential for testosterone to be aromatized to estrogen. Animal studies suggest that testosterone may serve as a natural, endogenous protector of the breast and limit mitogenic and cancer promoting effects of estrogen on mammary epithelium. In premenopausal women, elevated testosterone is not associated with greater breast cancer risk. The risk of breast cancer is also not increased in women with polycystic ovary syndrome who have chronic estrogen exposure and androgen excess. However, in postmenopausal women, who are oestrogen deplete and have increased adipose aromatase activity, higher testosterone has been associated with greater breast cancer risk.

CONCLUSION

Available data indicate the inclusion of testosterone in estrogen-progestin regimens has the potential to ameliorate the stimulating effects of hormones on the breast. However, testosterone therapy alone cannot be recommended for estrogen deplete women because of the potential risk of enhanced aromatisation to estrogen in this setting.

Progesterone-independent effects of human progesterone receptors (PRs) in estrogen receptor-positive breast cancer: PR isoform-specific gene regulation and tumor biology

Progesterone receptors (PRs) are prognostic markers in breast cancers irrespective of the patient's progestational status. However, there are two PR isoforms, PR-A and PR-B, that are equimolar in the normal breast but dysregulated in advanced disease. Postmenopausal, tamoxifen-treated patients with estrogen receptor (ER)-positive, PR-A-rich tumors have much faster disease recurrence than patients with PR-B-rich tumors. To study the mechanisms we engineered ER+ breast cancer cells that express each PR isoform under control of an inducible promoter. We identified 79 genes regulated by progesterone (P), mainly by PR-B, and 51 genes regulated without progesterone, mainly by PR-A. Only nine genes were regulated with and without ligand, leading to definition of three classes: I) genes regulated only by liganded PR; II) genes regulated only by unliganded PR; III) genes regulated by both. Unliganded PR-A and PR-B differentially regulate genes that coordinate extracellular signaling pathways and influence tumor cell biology. Indeed, in the absence of P, compared with ER+/PR-B+ or PR- cells, ER+, PR-A+ cells exhibit an aggressive phenotype, are more adhesive to an extracellular matrix, and are more migratory. Additionally, unliganded PR-A and PR-B both inhibit cell growth and provoke resistance to Taxol-induced apoptosis. We propose that PR-A:PR-B ratios, even in the absence of P, influence the biology and treatment response of ER+ tumors, that PR-A isoforms are functionally dominant in P-deficient states, and that PR-A rich tumors are especially aggressive.

Breast Cancer Chemoprevention Phase I Evaluation of Biomarker Modulation by Arzoxifene, a Third Generation Selective Estrogen Receptor Modulator

PURPOSE

Arzoxifene, a new selective estrogen receptor modulator with strong breast antiestrogen activity and absence of uterine agonist activity, was explored as a potential chemoprevention agent. We performed a multi-institutional evaluation of arzoxifene in women with newly diagnosed ductal carcinoma in situ or T1/T2 invasive cancer.

EXPERIMENTAL DESIGN

In a Phase IA trial, 50 pre- or postmenopausal women were randomized to 10, 20, or 50 mg of arzoxifene daily in the interval between biopsy and re-excision or were enrolled as no-treatment controls. In a Phase IB trial, 76 postmenopausal women were randomized to 20 mg of arzoxifene versus matched placebo. Serum specimens collected at entry and at re-excision were assayed for various hormones and growth factors. Tissue from biopsies (estrogen receptor + and/or progesterone receptor +) and re-excision specimens was evaluated immunohistochemically for proliferation (Ki-67 by MIB-1 and proliferating cell nuclear antigen) and other biomarkers.

RESULTS

In both trials, increases in serum sex hormone binding globulin were noted, as were decreases in insulin-like growth factor (IGF)-I and the IGF-I:IGF binding protein-3 ratio (P < 0.007 versus control/placebo). For 45 evaluable women in Phase IA, decreases in proliferation indices were more prevalent for arzoxifene (particularly 20 mg) than for controls. For 58 evaluable women in Phase IB, a decrease in estrogen receptor expression for arzoxifene was observed compared with no change with placebo (P = 0.0068). However, decreases in proliferation indices for arzoxifene were not statistically different from placebo, perhaps due to a confounding effect of stopping hormone replacement therapy before entry.

CONCLUSION

Given the favorable side effect profile and the biomarker modulations reported here, arzoxifene remains a reasonable candidate for additional study as a breast cancer chemoprevention agent.

Testosterone effects on the breast: implications for testosterone therapy for women

Androgens have important physiological effects in women. Postmenopausal androgen replacement, most commonly as testosterone therapy, is becoming increasingly widespread. This is despite the lack of clear guidelines regarding the diagnosis of androgen insufficiency, optimal therapeutic doses, and long-term safety data. With respect to the breast specifically, there is the potential for exogenous testosterone to exert either androgenic or indirect estrogenic actions, with the latter potentially increasing breast cancer risk. In experimental studies, androgens exhibit growth-inhibitory and apoptotic effects in some, but not all, breast cancer cell lines. Differing effects between cell lines appear to be due primarily to variations in concentrations of specific coregulatory proteins at the receptor level. In rodent breast cancer models, androgen action is antiproliferative and proapoptotic, and is mediated via the androgen receptor, despite the potential for testosterone and dehydroepiandrosterone to be aromatized to estrogen. The results from studies in rhesus monkeys suggest that testosterone may serve as a natural endogenous protector of the breast and limit mitogenic and cancer-promoting effects of estrogen on mammary epithelium. Epidemiological studies have significant methodological limitations and provide inconclusive results. The strongest data for exogenous testosterone therapy comes from primate studies. Based on such simulations, inclusion of testosterone in postmenopausal estrogen-progestin regimens has the potential to ameliorate the stimulating effects of combined estrogen-progestin on the breast. Research addressing this is warranted; however, the number of women that would be required for an adequately powered randomized controlled trial renders such a study unlikely.

Short-term biologic response to withdrawal of hormone replacement therapy in patients with invasive breast carcinoma

BACKGROUND

The biologic effect of continuing hormone replacement therapy (HRT) after a diagnosis of breast carcinoma is unclear. The goal of rhe current study was to determine the short-term effect of HRT withdrawal on invasive breast carcinoma using biologic surrogate markers of tumor response.

METHODS

The study was performed between 1996 and 2000 and comprised 140 women who had been using HRT at the time of breast carcinoma diagnosis by core needle biopsy. The breast tumors were removed a median of 17 days later (range, 2-31 days). Of these women, 125 women stopped HRT at the time of core needle biopsy and 15 continued to receive HRT until surgery. In addition, 55 women with breast carcinoma from the same time period, who were not receiving HRT at diagnosis, were studied. Changes in expression of Ki-67 (a measure of epithelial cell proliferation), progesterone receptor (PR), p27KIP-1 (a cyclin-dependent kinase inhibitor), and cyclin D1 (a cell cycle-related protein) were determined by immunohistochemistry on paired sections of the core needle biopsy and surgical specimens from each patient.

RESULTS

In women who stopped HRT, a significant decrease in Ki-67 expression was observed between core needle biopsy and surgery in estrogen receptor (ER)-positive (n = 106; P < 0.001), but not in ER-negative tumors (n = 19; P = 0.58), with an associated reduction in PR (P < 0.001) and cyclin D1 expression (P < 0.001) and an increase in p27KIP-1 (P = 0.03). These changes in Ki-67 and PR expression occurred irrespective of c-erb-B2 status. No change was observed in any parameter in the other groups of patients.

CONCLUSIONS

ER-positive invasive breast carcinomas demonstrated a favorable biologic response to withdrawal of HRT. Therefore, HRT should be stopped at the time of diagnosis and was subsequently contraindicated.

Studies of the Potential Utility of Ki67 as a Predictive Molecular Marker of Clinical Response in Primary Breast Cancer

INTRODUCTION

Objectives were to characterise the relationship of the proliferation marker Ki67 with response to systemic treatment in early breast cancer and to assess its clinical utility, using fine needle aspirates.

MATERIALS AND METHODS

Hundred and six women were treated with primary tamoxifen (n = 33), chemotherapy (n = 33) or chemotherapy and tamoxifen (n = 40). Treatment was not randomised and response was assessed clinically. Ki67 was evaluated prior to treatment and at Day 14 or 21 after commencing treatment. To assess reproducibility, Ki67 was evaluated in repeat FNAs taken from 37 untreated patients.

RESULTS

The percentage change in Ki67 in first 21 days was different between responders and non-responders for patients treated with tamoxifen (p = 0.007) and chemotherapy (p = 0.005) but not for chemoendocrine treatment (p = 0.062). The reproducibility study indicated that a decrease to 36% or less of the pre-treatment Ki67 value in an individual patient was required for it to be regarded as a statistically significant change. A significant decrease in Ki67 was seen in responding patients treated with chemotherapy (p = 0.026) and chemoendocrine treatment (p = 0.041). Positive and negative predictive values for response were 85 and 59% for chemotherapy patients and 88 and 54% for chemoendocrine patients, respectively.

CONCLUSION

Ki67 is unlikely to be useful as a predictive marker in individual patients. Further molecular markers that predict lack of response continue to be required.

Biological response to hormonal manipulation in oestrogen receptor positive ductal carcinoma in situ of the breast

Adjuvant antioestrogen therapy with tamoxifen is recommended for all women following breast-conserving surgery for ductal carcinoma in situ (DCIS) to reduce local recurrence, despite 50% of lesions being oestrogen receptor (OR) negative. We have investigated the response to hormone manipulation in DCIS by studying changes in epithelial proliferation and progesterone receptor (PR) expression as surrogate molecular markers of treatment effects in DCIS of known OR status. Women were identified who had undergone diagnostic core biopsy followed by surgery for DCIS 14-41 days later. Ki67 (a measure of epithelial cell proliferation) and PR expression were determined by immunohistochemistry on paired paraffin sections of the core biopsy and operative specimens for each patient, with OR and HER-2 measured on the operative specimen. Women were divided into three groups according to whether they had changed hormone therapy (stopped hormone replacement therapy (HRT), group 1), continued taking HRT (group 2) or were not taking HRT (group 3) between core biopsy and surgery. In OR-positive (but not in OR-negative) DCIS after oestrogen withdrawal (group 1), a fall in the mean cell proliferation (P&<0.01) was observed. A fall in PR expression between core biopsy and surgery was also seen in this group (P=0.02). No change in either mean cell proliferation or PR expression was seen in the other two groups in OR-positive or -negative DCIS. The fall in proliferation and PR expression occurred regardless of HER-2 status. In conclusion, a biological response to hormone manipulation is only seen in OR-positive DCIS tumours. Any clinical value of antioestrogen therapy is likely to be restricted to this group.

A randomized trial of low-dose tamoxifen on breast cancer proliferation and blood estrogenic biomarkers

BACKGROUND

Tamoxifen reduces the risk of breast cancer in women at high risk for the disease but increases the risk for endometrial tumors and venous thromboembolisms, possibly in a dose-dependent fashion. We compared the effects of tamoxifen at 1 mg/day and 5 mg/day with those of the standard dose of 20 mg/day on breast cancer proliferation using a surrogate endpoint marker (Ki-67 expression) and blood biomarkers associated with breast cancer, cardiovascular disease, and bone fracture risk.

METHODS

We randomly assigned 120 women with estrogen receptor (ER)-positive breast cancer to tamoxifen at 1, 5, or 20 mg/day for 4 weeks. Expression of the tumor proliferation marker Ki-67 and of biomarkers of breast cancer (insulin-like growth factor-I, sex hormone-binding globulin), cardiovascular disease (cholesterol, triglycerides, ultrasensitive C-reactive protein, fibrinogen, antithrombin-III), and bone fracture (type I collagen C-telopeptide) risk were determined before (baseline) and after treatment. All levels were compared with those in two nonrandomized control groups (34 women with ER-negative breast cancer and 29 additional women with ER-positive breast cancer). Data were analyzed by analysis of covariance. All statistical tests were two-sided.

RESULTS

Expression of Ki-67 decreased in all three tamoxifen groups, with no difference in the magnitude of reduction among groups (P =.81). Relative to baseline, Ki-67 expression decreased by a median of 15.0% (95% confidence interval = 0.0% to 24.1%) among the tamoxifen groups but increased by 12.8% (95% confidence interval = 0.0% to 19.6%) among the nonrandomized control groups. Several blood biomarkers showed dose-response relationships with tamoxifen, including decreased insulin-like growth factor-I, increased sex hormone-binding globulin, and decreased low-density lipoprotein-cholesterol, ultrasensitive C-reactive protein, fibrinogen, and antithrombin-III levels.

CONCLUSIONS

The effects on Ki-67 expression of lower doses of tamoxifen were comparable to those achieved with the standard dose, although the effects on blood biomarkers were variable. The effects of lower doses of tamoxifen should be assessed further in randomized trials.

Effects of low dose tamoxifen on normal breast tissue from premenopausal women

The aim of this study was to determine the effects of low doses of tamoxifen (5 and 10mg/day) for 50 days compared with the standard dose (20 mg/day) on breast biomarkers measured in normal breast tissue from premenopausal patients. A randomised double-blind study was performed using tissue from 56 premenopausal women with a diagnosis of fibroadenoma of the breast. Excisional biopsy was performed on the 50th day of therapy. Normal breast tissue samples were collected during surgery. The patients were divided in groups: A (placebo, n=11); group B (5 mg, n=16), group C (10 mg, n=14) and group D (20 mg, n=15). In this cross-sectional study, differences in the expression of Oestrogen Receptor alpha (ERalpha), Progesterone Receptor (PR), Ki-67, apoptotic bodies and mitotic index between the different groups after treatment can be seen on the normal breast tissue. We believe that a lower dose of tamoxifen could reduce the side-effects associated with treatment without affecting its chemopreventive activity in the breast.

MIB-1 Assessments in breast cancers

The variability of MIB-1 measurements in breast cancer was assessed in histological sections from core and excision biopsies taken simultaneously in 13 cases and sequentially (with an intervening period of 2-3 weeks) in 17 cases. Results showed no significant differences in values between cores and sections, whether taken simultaneously or sequentially. Individual pairs of cores and sections occasionally demonstrated substantial differences. The mean ratio of MIB-1 scores between cores and sections was 0.97 [95% confidence interval (CI)=0.68-1.38]. However 95% confidence intervals for ratios within individuals were 0.14-6.68. Although the two samples can be equivalent on an average over numerous patients, they cannot be taken as equivalent within individuals. Severe heterogeneity complicates the assessment of MIB-1 in individual breast cancers and limits utility in monitoring changes in proliferation with treatment.