Additive antitumour effect of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib (Iressa, ZD1839) and the antioestrogen fulvestrant (Faslodex, ICI 182,780) in breast cancer cells

Carcinosarcoma of breast - A chimera among breast neoplasms

Malignant phyllodes, along with ductal carcinoma, is known as metaplastic cancer of the breast. This tumor is additionally known as breast carcinosarcoma. Malignant phyllodes in conjunction with ductal carcinoma is a rare finding in routine clinical practice. We describe the case report of a 47-year-old female patient who arrived with a large right breast mass. A core biopsy was performed, and histopathological examination indicated that the tumor was a malignant phyllodes tumor. A positron emission tomography (PET) scan revealed hyper-metabolic and hypo-metabolic tumors with perilesional stranding and satellite nodularity. There were a few metastatic right axillary nodes visible. There was no indication of distant metastases. Due to the presence of both components, a modified radical mastectomy surgery with axillary dissection was undertaken for this patient. Histopathological analysis of paraffin sections revealed ductal carcinoma in situ (DCIS) comedo-epithelial component and spindle-shaped cells with hyper-chromatic oval nuclei and scanty cytoplasm.

Analysis of Clinicopathological Characteristics and Prognosis of Carcinosarcoma of the Breast

Background. Few cases of carcinosarcoma of the breast have been reported because of its low incidence rate and rapid progression. Seeking effective therapeutic methods becomes urgent in clinical practice. This study was aimed to investigate the clinical characteristics of carcinosarcoma of the breast and to explore proper therapeutic methods for patients with this rare tumor. Methods. We conducted a retrospective analysis on 47 patients with carcinosarcoma of the breast receiving treatment in our hospital from 2003 to 2020. Most of these patients received primary surgery followed by adjuvant chemotherapy, while four patients had lumpectomy only. Statistics showed no preference in age and menopausal status of patients. Results. The overall survival rate and progression-free survival rate of all patients at a median follow-up time of 33 months were 63.8% and 57.4%, respectively. Tumor size at diagnosis and chemotherapy strategies were both significant prognostic factors in reference to disease-free survival (DFS) and overall survival (OS) of the patients (tumor size: $p=0.023$ for DFS and $p=0.021$ for OS; therapeutic method: $p=0.041$ for DFS and $p=0.024$ for OS). N stage at diagnosis was significant only with reference to overall survival of the patients ( $p=0.009$ ). EGFR expression was positive in some patients. Conclusions. Our results elucidated that the patients received comprehensive therapy, especially adjuvant chemotherapy was indispensable for better outcomes. Early detection and treatment were necessary for a higher survival rate when the tumor size was less than 5 cm without lymph node metastasis. Prospective outcomes with novel strategies targeting EGFR need to be further investigated.

A Case of Carcinosarcoma of the Breast Presenting as Inflammatory Carcinoma and Review of the Literature

Carcinosarcoma, also known as metaplastic carcinoma, is a rare and aggressive malignant tumor. We report a case of metaplastic carcinoma presenting as inflammatory carcinoma and provide a review of the related literature. A 38-year-old breastfeeding woman presented with concerns about a painful lump in her left breast. The symptoms had been present for two months. After admission to the hospital, the triple assessment revealed findings consistent with inflammatory carcinoma of the breast. The patient underwent modified radical mastectomy. Histopathological examination revealed a gray-white tumor with a biphasic pattern with features of ductal carcinoma as well as squamous and sarcomatous differentiation. On immunohistochemistry, the neoplastic cells were positive for cytokeratin and vimentin, and focally positive for smooth muscle antigen (SMA) and negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER-2/neu). Based on histological and immunohistochemical findings, the tumor was diagnosed as carcinosarcoma. Four of eighteen dissected axillary lymph nodes were positive for metastasis. Carcinosarcoma is often a triple-negative tumor. The lack of standardized treatment protocols frequently leads to poor prognosis and can pose a diagnostic dilemma; it should be part of the differential diagnosis for a case of carcinoma of the breast presenting as inflammatory carcinoma.

Identification of driver genes and key pathways of prolactinoma predicts the therapeutic effect of genipin

The purpose of the present study was to identify the potential targets and markers for diagnosis, therapy and prognosis in patients with prolactinoma at the molecular level and to determine the therapeutic effects of genipin in prolactinoma. The gene expression profiles of GSE2175, GSE26966 and GSE36314 were obtained from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified after comparing between gene expression profiles of the prolactinoma tissues and normal tissues. Then, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and protein‑protein interaction (PPI) network analysis were conducted. In addition, in vitro, scratch assay, colony‑forming assay, Cell Counting Kit 8 (CCK8) assay and flow cytometry were performed to verify the functional effects of genipin. An aggregate of 12,695, 3,847 and 5,310 DEGs were identified from GSE2175, GSE26966 and GSE36314, respectively. The results of GO and KEGG analysis showed that the DEGs significant and important for prolactinoma were mostly involved with 'spindle pole' and 'oocyte meiosis'. A total of 20 genes were selected as hub genes with high degrees after PPI network analysis, including mitogen‑activated protein kinase 1 (MAPK1), MYC, early growth response 1 (EGR1), Bcl2 and calmodulin 1 (CALM1). CCK8 assay, colony‑forming assay and scratch assay were performed to verify the anti‑prolactinoma effect of genipin. The results of flow cytometry showed that apoptosis was increased by genipin. MAPK1, MYC, EGR1, Bcl2 and CALM1 were screened as main hub genes. Genipin upregulated the expression level of EGR1 and p21 (downstream mediator of EGR1) and EGR1, inhibited the proliferation and migration of prolactinoma cells. Genipin is a promising drug for treatment of patients with prolactinoma.

Extended Adjuvant Therapy with Neratinib Plus Fulvestrant Blocks ER/HER2 Crosstalk and Maintains Complete Responses of ER+/HER2+ Breast Cancers: Implications to the ExteNET Trial

PURPOSE

The phase III ExteNET trial showed improved invasive disease-free survival in patients with HER2⁺ breast cancer treated with neratinib versus placebo after trastuzumab-based adjuvant therapy. The benefit from neratinib appeared to be greater in patients with ER⁺/HER2⁺ tumors. We thus sought to discover mechanisms that may explain the benefit from extended adjuvant therapy with neratinib.Experimental Design: Mice with established ER⁺/HER2⁺ MDA-MB-361 tumors were treated with paclitaxel plus trastuzumab ± pertuzumab for 4 weeks, and then randomized to fulvestrant ± neratinib treatment. The benefit from neratinib was evaluated by performing gene expression analysis for 196 ER targets, ER transcriptional reporter assays, and cell-cycle analyses.

RESULTS

Mice receiving "extended adjuvant" therapy with fulvestrant/neratinib maintained a complete response, whereas those treated with fulvestrant relapsed rapidly. In three ER⁺/HER2⁺ cell lines (MDA-MB-361, BT-474, UACC-893) but not in ER⁺/HER2^- MCF7 cells, treatment with neratinib induced ER reporter transcriptional activity, whereas treatment with fulvestrant resulted in increased HER2 and EGFR phosphorylation, suggesting compensatory reciprocal crosstalk between the ER and ERBB RTK pathways. ER transcriptional reporter assays, gene expression, and immunoblot analyses showed that treatment with neratinib/fulvestrant, but not fulvestrant, potently inhibited growth and downregulated ER reporter activity, P-AKT, P-ERK, and cyclin D1 levels. Finally, similar to neratinib, genetic and pharmacologic inactivation of cyclin D1 enhanced fulvestrant action against ER⁺/HER2⁺ breast cancer cells.

CONCLUSIONS

These data suggest that ER blockade leads to reactivation of ERBB RTKs and thus extended ERBB blockade is necessary to achieve durable clinical outcomes in patients with ER⁺/HER2⁺ breast cancer.

Randomized phase II study of fulvestrant and erlotinib compared with erlotinib alone in patients with advanced or metastatic non-small cell lung cancer

OBJECTIVES

This open-label, randomized phase II trial evaluated antitumor efficacy of an antiestrogen, fulvestrant, in combination with human epidermal growth factor receptor (EGFR) inhibitor, erlotinib, in advanced non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

Patients with advanced or metastatic NSCLC, ECOG 0-2, previous chemotherapy unless patient refusal, and no prior EGFR-directed therapy were randomized 2:1 to erlotinib 150 mg oral daily plus 500 mg intramuscular fulvestrant on day 1, 15, 29 and every 28 days thereafter or erlotinib alone 150 mg oral daily. The primary end point was objective response rate (ORR); secondary endpoints included progression free survival (PFS) and overall survival (OS).

RESULTS

Among 106 randomized patients, 100 received at least one dose of study drug. ORR was 16.4% (11 of 67 patients) for the combination versus 12.1% (4 of 33 patients) for erlotinib (p = 0.77). PFS median 3.5 versus 1.9 months [HR = 0.86, 95% CI (0.52-1.43), p = 0.29] and OS median 9.5 versus 5.8 months [HR = 0.92, 95% CI (0.57-1.48), p = 0.74] numerically favored the combination. In an unplanned subset analysis, among EGFR wild type patients (n = 51), but not EGFR mutant patients (n = 17), median PFS was 3.5 versus 1.7 months [HR = 0.35, 95% CI (0.14-0.86), p = 0.02] and OS was 6.2 versus 5.2 months [HR = 0.72, 95% CI (0.35-1.48), p = 0.37] for combined therapy versus erlotinib, respectively. Notably, EGFR WT patients were more likely to be hormone receptor-positive (either estrogen receptor α- and/or progesterone receptor-positive) compared to EGFR mutant patients (50% versus 9.1%, respectively) (p = 0.03). Treatment was well tolerated with predominant grade 1-2 dermatologic and gastrointestinal adverse effects.

CONCLUSION

Addition of fulvestrant to erlotinib was well tolerated, with increased activity noted among EGFR wild type patients compared to erlotinib alone, albeit in an unplanned subset analysis.

Carcinosarcoma (Metaplastic Carcinoma) Breast: A Rare and Aggressive Primary – Report of Two Cases with Review of Literature

Carcinosarcoma (CS) also known as metaplastic carcinoma of the breast is a rare and aggressive type of malignancy with controversial origin. Currently, there are no standard treatment guidelines outlined, owing to the rarity of the disease, but according to the available literature, surgery followed by adjuvant radiation therapy has the greatest benefit. We are presenting two cases of CS of breast developing metastasis. One of the cases presented with lung metastasis during the course of follow-up and responded significantly to chemotherapy, and the other is currently receiving chemotherapy. The cases are being presented here along with the literature review enlightening the current knowledge and available treatment options.

Three-dimensional organotypic matrices from alternative collagen sources as pre-clinical models for cell biology

Organotypic co-cultures bridge the gap between standard two-dimensional culture and mouse models. Such assays increase the fidelity of pre-clinical studies, to better inform lead compound development and address the increasing attrition rates of lead compounds within the pharmaceutical industry, which are often a result of screening in less faithful two-dimensional models. Using large-scale acid-extraction techniques, we demonstrate a step-by-step process to isolate collagen I from commercially available animal byproducts. Using the well-established rat tail tendon collagen as a benchmark, we apply our novel kangaroo tail tendon collagen as an alternative collagen source for our screening-ready three-dimensional organotypic co-culture platform. Both collagen sources showed equal applicability for invasive, proliferative or survival assessment of well-established cancer models and clinically relevant patient-derived cancer cell lines. Additional readouts were also demonstrated when comparing these alternative collagen sources for stromal contributions to stiffness, organization and ultrastructure via atomic force microscopy, second harmonic generation imaging and scanning electron microscopy, among other vital biological readouts, where only minor differences were found between the preparations. Organotypic co-cultures represent an easy, affordable and scalable model to investigate drug responses within a physiologically relevant 3D platform.

A rare case of true carcinosarcoma of the breast

BACKGROUND

True carcinosarcoma of the breast is an extremely rare condition, accounting for 0.08-0.2% of all breast malignancies. The correct definition of this tumor requires both a carcinomatous component and a malignant non-epithelial component of mesenchymal origin, without evidence of a transition zone between the two elements.

CASE PRESENTATION

We present a case of a 49-year-old woman presenting with a 4cm mass at the level of her left breast upper-outer quadrant with a histologic diagnosis of true carcinosarcoma of the breast.

DISCUSSION

The most appropriate therapeutic regimens for breast carcinosarcoma are still unclear because of the rarity of this condition, but Breast Conserving Treatment (BCT) followed by adjuvant chemotherapy seems to provide a prognosis equalling that of usual Invasive Ductal Carcinoma of the breast.

Smoking out reproductive hormone actions in lung cancer

Experimental and population-based evidence has been steadily accumulating that steroid hormones are fundamentally involved in the biology of the lung. Both estrogen and progesterone receptors are present in normal and malignant lung tissue, and the reproductive hormones that bind these receptors have a role in lung development, lung inflammation, and lung cancer. The estrogen receptor-β (ER-β) was discovered in the 1990s as a novel form of ER that is transcribed from a gene distinct from ER-α, the receptor previously isolated from breast tissue. Interestingly, ER-β is the predominate ER expressed in normal and malignant lung tissue, whereas inflammatory cells that infiltrate the lung are known to express both ER-α and ER-β. Although there is evidence from animal models for the preferential effects of ER-β in the lungs of females, human lung tumors from males often contain comparable numbers of ER-β-positive cells and male-derived lung cancer cell lines respond to estrogens. Lung tumors from both males and females also express CYP19 (aromatase), the rate-limiting enzyme in estrogen synthesis that converts testosterone to estrone and β-estradiol. Thus, testosterone acts as a precursor for local estrogen production within lung tumors, independent of reproductive organs. This review discusses the recent literature findings about the biology of the ERs, aromatase, and the progesterone receptor in lung cancer and highlights the ongoing clinical trials and future therapeutic implications of these findings.

Estrongenic steroid hormones in lung cancer

It is becoming increasingly clear that steroid hormones are involved in the biology of many organs outside the reproductive system. Evidence has been accumulating since the mid 1990s that the lung contains receptors for both estrogen and progesterone and that these hormones have some role in lung development, pulmonary inflammation, and lung cancer. The estrogen receptor β (ERβ) is the major ER expressed in lung tissues, while inflammatory cells capable of infiltrating the lung are reported to express both ERα and ERβ. Although there is evidence in animals of preferential effects of ERβ in the lungs of females, human lung tumors from males also contain ERβ-positive cells and express aromatase, the enzyme that converts testosterone to estrogens. This review will discuss current literature findings on the role of the ERs and the progesterone receptor (PR), as well CYP19 (aromatase), the rate-limiting enzyme in the synthesis of estrogen, in lung cancer.

[A rare and distinct tumor of breast cancer: carcinosarcoma, about eight cases and review of the literature]

Le carcinosarcome du sein souvent appelé carcinome métaplasique du sein, est une tumeur maligne rare composée de deux lignées cellulaires distinctes, il est décrit comme un cancer du sein de type canalaire avec un composant de type sarcome. Il représente 0,08-0.2% de toutes les tumeurs malignes du sein. Il s'agit d'une étude rétrospective étalée sur un an, huit cas des carcinosarcomes mammaires ont été colligés à l'Institut national d'oncologie au Maroc durant l'année 2007. La médiane d’âge était de 49,5 ans, toutes les tumeurs étaient de haut grade, cliniquement 5 cas ont été classé t2 ou t3, et 3 cas classé sein localement avancé. Le traitement envisagé était basé sur une chirurgie mammaire suivie d'une radiothérapie et d'une chimiothérapie pour les cas adjuvants, l'envahissement ganglionnaire a été noté dans un cas, les récepteurs œstrogèniques sont négatifs, alors que les récepteurs progesteroniques sont positifs dans 4 cas, l'expression d'Her2 est absente dans tous les cas, le traitement des carcinosarcomes mammaires métastatiques était basé sur une chimiothérapie palliative. A 20 mois de médiane follow-up, la survie sans progression(SSP) pour le groupe entier est de 62,5%. Dans la limite de ce suivi, une rechute locorégionale a été détectée dans un cas, les deux patientes métastatiques sont décédées. Le carcinosarcome du sein est un sous-type rare du cancer du sein qui a un profil particulier et agressif, il a souvent un caractère triple négatif. Il est nécessaire de développer d'autres voies de recherche comme cibler le Récepteur HER1/EGFR.

Ubiquitin ligase Cbl-b is involved in icotinib (BPI-2009H)-induced apoptosis and G1 phase arrest of EGFR mutation-positive non-small-cell lung cancer

Epidermal growth factor receptor (EGFR) is one of the most promising targets for non-small-cell lung cancer (NSCLC). Icotinib, a highly selective EGFR tyrosine kinase inhibitor (EGFR-TKI), has shown promising clinical efficacy and safety in patients with NSCLC. The exact molecular mechanism of icotinib remains unclear. In this study, we first investigated the antiproliferative effect of icotinib on NSCLC cells. Icotinib significantly inhibited proliferation of the EGFR-mutated lung cancer HCC827 cells. The IC₅₀ values at 48 and 72 h were 0.67 and 0.07 μM, respectively. Flow cytometric analysis showed that icotinib caused the G1 phase arrest and increased the rate of apoptosis in HCC827 cells. The levels of cyclin D1 and cyclin A2 were decreased. The apoptotic process was associated with activation of caspase-3, -8, and poly(ADP-ribose) polymerase (PARP). Further study revealed that icotinib inhibited phosphorylation of EGFR, Akt, and extracellular signal-regulated kinase. In addition, icotinib upregulated ubiquitin ligase Cbl-b expression. These observations suggest that icotinib-induced upregulation of Cbl-b is responsible, at least in part, for the antitumor effect of icotinib via the inhibition of phosphoinositide 3-kinase (PI3K)/Akt and mitogen-activated protein kinase pathways in EGFR-mutated NSCLC cells.

A mechanistic study of the effect of doxorubicin/adriamycin on the estrogen response in a breast cancer model

OBJECTIVE

Estrogen treatment limits the cytotoxic effects of chemotherapy in estrogen receptor-positive (ER+) breast cancer cell lines, suggesting that estrogen pathway signaling may confer chemotherapeutic resistance. This study investigates the molecular responses of ER+ breast cancer cell lines to the chemotherapeutic agent, doxorubicin, in the presence or absence of estrogen.

METHODS

ER+ MCF-7 and T47-D cells were cultured in hormone-starved or estrogen-containing media with or without doxorubicin at concentrations mimicking the low concentrations seen in plasma and tumor microenvironments in humans following typical bolus administration. Protein levels, phosphorylations, and interactions of estrogen-signaling molecules were assessed following these treatments, as well the effects of ER signaling inhibitors on cell proliferation.

RESULTS

Surprisingly, estrogen and doxorubicin co-treatment markedly induced pro-growth alterations compared to doxorubicin alone and modestly enhanced estrogen alone-induced changes. Several inhibitors suppressed cell proliferation in the presence of doxorubicin and estrogen.

CONCLUSIONS

These findings demonstrate that molecular changes caused by doxorubicin in ER+ breast cancer cells can be reversed by estrogen, providing molecular evidence for the poorer responses of ER+ tumors to doxorubicin in the presence of physiologic estrogen levels. Our results also suggest that the addition of drugs targeting the ER, EGFR, the SFKs, MEK, PI3K, and/or the MMP proteins to a conventional chemotherapy regimen may improve chemosensitivity.

The Concept of Divergent Targeting through the Activation and Inhibition of Receptors as a Novel Chemotherapeutic Strategy: Signaling Responses to Strong DNA-Reactive Combinatorial Mimicries

Recently, we reported the combination of multitargeted ErbB1 inhibitor-DNA damage combi-molecules with OCT in order to downregulate ErbB1 and activate SSTRs. Absence of translation to cell kill was believed to be partially due to insufficient ErbB1 blockage and DNA damage. In this study, we evaluated cell response to molecules that damage DNA more aggressively and induce stronger attenuation of ErbB1 phosphorylation. We used three cell lines expressing low levels (U87MG) or transfected to overexpress wildtype (U87/EGFR) or a variant (U87/EGFRvIII) of ErbB1. The results showed that Iressa ± HN2 and the combi-molecules, ZRBA4 and ZR2003, significantly blocked ErbB1 phosphorylation in U87MG cells. Addition of OCT significantly altered cell cycle distribution. Analysis of the DNA damage response pathway revealed strong upregulation of p53 by HN2 and the combi-molecules. Apoptosis was only induced by a 48 h exposure to HN2. All other treatments resulted in cell necrosis. This is in agreement with Akt-Bad pathway activation and survivin upregulation. Despite strong DNA damaging properties and downregulation of ErbB1 phosphorylation by these molecules, the strongest effect of SSTR activation was on cell cycle distribution. Therefore, any enhanced antiproliferative effects of combining ErbB1 inhibition with SSTR activation must be addressed in the context of cell cycle arrest.

Epithelial cell guidance by self-generated EGF gradients

Cancer epithelial cells often migrate away from the primary tumor to invade into the surrounding tissues. Their migration is commonly assumed to be directed by pre-existent spatial gradients of chemokines and growth factors in the target tissues. Unexpectedly however, we found that the guided migration of epithelial cells is possible in vitro in the absence of pre-existent chemical gradients. We observed that both normal and cancer epithelial cells can migrate persistently and reach the exit along the shortest path from microscopic mazes filled with uniform concentrations of media. Using microscale engineering techniques and biophysical models, we uncovered a self-guidance strategy during which epithelial cells generate their own guiding cues under conditions of biochemical confinement. The self-guidance strategy depends on the balance between three interdependent processes: epidermal growth factor (EGF) uptake by the cells (U), the restricted transport of EGF through the structured microenvironment (T), and cell chemotaxis toward the resultant EGF gradients (C). The UTC self-guidance strategy can be perturbed by inhibition of signalling through EGF-receptors and appears to be independent from chemokine signalling. Better understanding of the UTC self-guidance strategy could eventually help devise new ways for modulating epithelial cell migration and delaying cancer cell invasion or accelerating wound healing.

Cross-talk and modulation of signaling between somatostatin and growth factor receptors

The process of homo- and/or heterodimerization of G-protein coupled receptors (GPCRs) and receptor tyrosine kinase (RTK) families are crucial for implicating the fundamental properties of receptor proteins including receptor expression, trafficking, and desensitization as well as signal transduction. The members of GPCR and RTK family constitute largest cell surface receptor proteins and regulate physiological functions of cells in response to external and internal stimuli. Notably, GPCRs and RTKs play major role in regulation of several key cellular functions which are associated with several pathological conditions including cancer biology, neurodegenerative and cardiovascular diseases. The focus of this review is to highlight the recent findings on the possible cross-talk between somatostatin receptors (members of GPCR family) and growth factor receptors like epidermal growth factor receptors (members of RTK family). Furthermore, functional consequences of such an interaction in modulation of signaling pathways linked to pathological conditions specifically in cancer are discussed.

Synergistic anticancer effects of combined γ-tocotrienol with statin or receptor tyrosine kinase inhibitor treatment

Systemic chemotherapy is the only current method of treatment that provides some chance for long-term survival in patients with advanced or metastatic cancer. γ-Tocotrienol is a natural form of vitamin E found in high concentrations in palm oil and displays potent anticancer effects, but limited absorption and transport of by the body has made it difficult to obtain and sustain therapeutic levels in the blood and target tissues. Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase and are an example of a promising cancer chemotherapeutic agent whose clinical usefulness has been limited due to high-dose toxicity. Similarly, erlotinib and gefitinib are anticancer agents that inhibit the activation of individual HER/ErbB receptor subtypes, but have shown limited clinical success because of heterodimerization between different EGF receptor family members that can rescue cancer cells from agents directed against a single receptor subtype. Recent studies have investigated the anticancer effectiveness of low-dose treatment of various statins or EGF receptor inhibitors alone and in combination with γ-tocotrienol on highly malignant +SA mouse mammary epithelial cells in vitro. Combined treatment with subeffective doses of γ-tocotrienol with these other chemotherapeutic agents resulted in a synergistic inhibition of +SA cell growth and viability. These findings strongly suggest that combined treatment of γ-tocotrienol with other anticancer agents may not only provide an enhanced therapeutic response but also provide a means to avoid the toxicity, low bioavailability, or limited therapeutic action associated with high-dose monotherapy.

Estrogen receptor expression in sporadic vestibular schwannomas

HYPOTHESIS

We hypothesize that vestibular schwannomas (VSs) exhibit up-regulation of estrogen receptor (ER) at the protein level compared with control great auricular nerve (GAN).

BACKGROUND

It has been reported in the literature that VS occur more commonly in women and tend to be larger and more vascular in women, and growth rate can accelerate during pregnancy. The literature contains widely divergent results on ER expression in VS, however, varying from no detectable levels to detection of ER in all samples.

METHODS

Sixteen sporadic VS specimens were immediately snap-frozen after microsurgical excision and analyzed for phosphorylated and total levels of ERα with Western blot analysis. ERα expression levels were normalized to actin; then, relative expression to GAN was determined.

RESULTS

All VS specimens exhibited expression of both phosphorylated and total ERα. Total ERα expression in VS is equivalent to or slightly up-regulated compared with GAN. VS specimens exhibited more pronounced up-regulation of phosphorylated (i.e., activated) levels of ERα compared with GAN.

CONCLUSION

We have demonstrated that ERα expression in VS is equivalent to GAN. The phosphorylated form of the receptor is up-regulated compared with GAN, however, indicating a higher level of ERα activation in sporadic VS compared with normal nerve. Further investigation into antiestrogen therapy for VS is warranted.

The epidermal growth factor receptor inhibitor gefitinib prevents the progression of pancreatic lesions to carcinoma in a conditional LSL-KrasG12D/+ transgenic mouse model

Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic malignancy with a dismal prognosis. Developing novel strategies to prevent or delay pancreatic cancer is currently of intense interest. The chemopreventive efficacy of gefitinib, an epidermal growth factor receptor (EGFR) inhibitor, was evaluated against the progression of pancreatic intraepithelial neoplasms (PanIN) to PDAC in conditional LSL-Kras(G12D/+) transgenic mice. LSL-Kras(G12D/+) and p48(Cre/+) mice were bred, and offspring of activated Kras(G12D/+) were generated. Six-week-old male Kras(G12D/+) (20 per group) and C57BL/6 wild-type (12 per group) mice were fed (AIN-76A) diets containing 0, 100, and 200 ppm of gefitinib for 35 weeks. At termination, pancreases were evaluated histopathologically for PanINs and PDAC, and various biomarkers were measured by immunohistochemistry, immunofluorescence, immunoblotting, and/or reverse transcription-PCR. Dietary gefitinib at 100 and 200 ppm significantly suppressed PDAC incidence by 77% and 100%, respectively (P < 0.0001) when compared with control diet. Importantly, a significant inhibition of carcinoma and a dose-dependent suppression of PanINs [PanIN-1, 37-62% (P < 0.002); PanIN-2, 38-41 (P < 0.001); and PanIN-3, 7-34% (P < 0.0141)] were observed in mice treated with gefitinib. Furthermore, mice treated with 100 and 200 ppm of gefitinib exhibited 67.6% to 77.3% of the pancreas to be free from ductal lesions. Also, gefitinib reduced EGFR, proliferating cell nuclear antigen, cyclin D1, C(2)GNT, RhoA, β-catenin, p38, phospho-extracellular signal-regulated kinase, caveolin-1, and mucin and increased cyclin B1 in the pancreatic lesions/PDAC. In summary, these results show that gefitinib can prevent the progression of pancreatic cancer precursor lesions to PDAC in a preclinical model. The present study highlights the promise of chemoprevention and the potential usefulness of EGFR inhibitors in individuals at high risk for pancreatic cancer.

Receptor activation and inhibition in cellular response to chemotherapeutic combinational mimicries: the concept of divergent targeting

The antiproliferative effect of tandem somatostatin receptor (SSTR) activation, epidermal growth factor receptor (EGFR) inhibition, and induction of DNA damage was analyzed using octreotide (OCT), a SSTR agonist, the clinical DNA methylating agent temozolomide (TMZ), Iressa, an EGFR inhibitor, and dual EGFR-DNA targeting agents termed "combi-molecules". Using SSTR-expressing glioma cells harbouring low levels of EGFR (U87MG) or transfected to overexpress EGFR (U87/EGFR) or a variant (U87/EGFRvIII), we showed that Iressa, alone or in combination with the DNA damaging agent TMZ, and combi-molecules RA2 and RA5 inhibited EGF-induced phosphorylation of EGFR in U87MG and more moderately in U87/EGFR and U87/EGFRvIII transfected cells. This translated into equivalent levels of Erk 1/2 inhibition. Activation of SSTRs with OCT did not modulate the effects of the various treatments on Erk 1/2 phosphorylation. Likewise, SSTR activation did not alter TMZ- or DNA-damaging combi-molecules, RA2 and RA5, induced p53 activation nor upregulation. However, SSTR activation significantly shifted TMZ-, RA2- and RA5-induced cell-cycle arrest to earlier phases (i.e., G2/M to late S, late S to S, S to G1). Further analysis showed that apoptosis was not induced. This was in agreement with the fact that p53 activation did not induce Bax upregulation nor did EGFR inhibition promote Bad dephosphorylation. Moreover, enhancement of survivin, an anti-apoptotic protein, expression was observed. The results in toto suggest that the combination of SSTR activation with EGFR inhibition and DNA damage affects cell-cycle progression but a disconnection between the targeted signalling pathways in these brain tumour cells precludes synergistic cell-killing by the triple growth inhibitory events.

Enhanced antiproliferative and apoptotic response to combined treatment of gamma-tocotrienol with erlotinib or gefitinib in mammary tumor cells

Background

Aberrant ErbB receptor signaling is associated with various types of malignancies. γ-Tocotrienol is a member of the vitamin E family of compounds that displays potent anticancer activity that is associated with suppression in ErbB receptor phosphorylation and mitogenic signaling. Erlotinib and gefitinib are tyrosine kinase inhibitors that block ErbB1 receptor activation, whereas trastuzumab is a monoclonal antibody that has been designed to specifically inhibit ErbB2 receptor activation. However, the clinical effectiveness of these agents have been disappointing because of cooperation between different ErbB family members that can rescue cancer cells from agents directed against a single ErbB receptor subtype. It was hypothesized that targeting multiple ErbB receptor subtypes with combined treatment of γ-tocotrienol and ErbB receptor inhibitors would provide greater anticancer effects than monotherapy targeting only a single ErbB receptor subtype.

Methods

Highly malignant mouse +SA mammary epithelial cells were maintained in culture on serum-free defined media containing 10 ng/ml EGF as a mitogen. Cell viability wase determined by MTT assay, whereas Western blot and immunofluorescent staining was used to determine treatment effects on ErbB receptor subtype level and activation. Treatment-induced apoptosis was determined using annexin V staining and Western blot analysis of cleaved caspase-3 and PARP levels.

Results

Treatment with 3.5 μM γ-tocotrienol, 0.5 μM erlotinib or 1.0 μM gefitinib alone, significantly inhibited +SA tumor cell growth. Combined treatment with subeffective doses of erlotinib (0.25 μM) or gefitinib (0.5 μM) with subeffective doses of γ-tocotrienol (0.5-3.0 μM) significantly inhibited the growth and induced apoptosis in a dose-responsive manner. Trastuzumab treatment alone or in combination had no effect on +SA cell growth and viability. Combined treatment of γ-tocotrienol with erlotinib or gefitinib also cause a large decrease in ErbB3, ErbB4, and to a lesser extent ErbB2 receptor levels, and EGF-dependent ErbB2-4 tyrosine phosphorylation (activation), but had no effect on ErbB1 receptor levels or activation.

Conclusion

Combination treatment of γ-tocotrienol with specific ErbB receptor inhibitors is more effective in reducing mammary tumor cell growth and viability than high dose monotherapy, suggesting that targeting multiple ErbB receptors with combination therapy may significantly improve the therapeutic response in breast cancer patients.

Combined tamoxifen and gefitinib in non-small cell lung cancer shows antiproliferative effects

Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is approved for clinical use in the treatment of non-small cell lung cancer (NSCLC). According to statistics, NSCLC patients who are female, have adenocarcinoma, or never smoked have a higher response rate to gefitinib treatment. This phenomenon could be due to the interaction between the estrogen receptor (ER) and EGFR. To test whether inhibition of the EGFR signaling pathway affects the antitumour effect of gefitinib, NSCLC cell lines were treated with gefitinib and tamoxifen, an ER antagonist. Cotreatment with gefitinib plus tamoxifen decreased the proliferation and increased the apoptosis of A549 and H1650 adencarcinoma cell lines, when compared with either drug alone. However, there was no effect on H520 cells (squamous cell carcinoma). Rapid activation of the EGFR pathway by both EGF and beta-E2 was observed in A549 cells. Additionally, EGFR and ERbeta expression was down-regulated in response to estrogen and EGF, respectively, but up-regulated in response to tamoxifen and genfitib, respectively. These results suggest that there is a functional cross-signaling between the EGFR and the ER pathways in NSCLC, possibly providing a rationale to combine gefitinib with anti-estrogen therapy for lung cancer treatment.

Recent advances in systemic therapy. When HER2 is not the target: advances in the treatment of HER2-negative metastatic breast cancer

The anti-human epidermal growth factor receptor 2 (HER2) agent trastuzumab has improved outcomes in breast cancer patients with HER2 over-expressing tumours. However, systemic treatment for patients with HER2-negative disease is still limited to endocrine and cytotoxic therapies. The increasing use of the anthracyclines and taxanes in early stage disease has reduced the available therapeutic options for patients with relapsed disease, and choices are further limited for patients with triple-negative tumours, who typically have a poor prognosis. The novel agents bevacizumab and ixabepilone were recently approved for metastatic breast cancer, and numerous other agents are currently in clinical development that may contribute further valuable therapeutic options.

Carcinosarcoma of the breast: two case reports and review of the literature

Carcinosarcoma of the breast, often referred to as metaplastic carcinoma of the breast, is a rare malignancy with two distinct cell lines described as a breast carcinoma of ductal type with a sarcoma-like component. Clinically, carcinosarcoma of the breast is an aggressive breast cancer. The prognosis for carcinosarcoma of the breast is less favorable compared to more common types of breast cancer such as infiltrating ductal or lobular carcinoma. Currently, the evaluation of breast carcinoma includes hormone receptor analysis of the tumor tissue, with those positive for estrogen or progesterone responding better to both hormonal and chemotherapy.Trastuzumab (Herceptin(R)) is available as an adjunct treatment for tumors which over-express the HER2/neu gene. Typically, metaplastic carcinomas of the breast do not express the estrogen or progesterone receptors and do not over-express the HER2/neu oncogene. As a result of this "triple negative" phenotype, such tumors tend to be more aggressive and are unlikely to respond to targeted therapy with Herceptin. The epidermal growth factor receptor HER-1/EGFR protein is expressed in the majority of metaplastic carcinomas and thus may serve as a potential therapeutic target for EGFR inhibitors such as gefitinib and cetuximab. The two cases we describe exemplify the aggressive nature of carcinosarcoma of the breast and support the findings that this tumor type does not express the common receptors found in other breast carcinomas. These case reports also emphasize the need for investigating the role for blockade of the HER-1/EGFR receptor with targeted therapies when found to be over-expressed in the primary tumor.

Current clinical trials of endocrine therapy for breast cancer

Breast cancer is a hormone-dependent cancer like prostate cancer and endometrial cancer. Estrogen plays important roles in the development and progression of breast cancer. Endocrine therapy is the treatment of choice for estrogen receptor- and/or progesterone receptor-positive breast cancer. Endocrine therapy has been used for several purposes, including chemoprevention, preoperative treatment, postoperative adjuvant treatment and treatment for recurrent diseases. A large number of clinical trials have provided evidence showing the clinical benefits of various endocrine therapies for the treatment of breast cancer. The current status and recent advances in endocrine therapy for breast cancer are reviewed based on the results of current clinical trials. Future perspectives of endocrine therapy are also discussed.

Hormonal therapy for advanced breast cancer

Hormonal therapy for advanced breast cancer has evolved significantly in the more than 100 years since the first publications documenting the effect of ovarian ablation on advanced breast cancer in premenopausal women. Since that time, not only have we developed the methods to measure estrogen and progesterone receptors in cancer cells, but more recently we have understood that expression of these receptors determines response to hormone therapy. The availability of more selective antiestrogen therapies has changed and significantly improved the treatment options for women who have advanced hormone-responsive breast cancer. Current research is focusing on reversing resistance to hormone therapy with the addition of targeted biologic agents to standard hormonal treatment.

Pathways to tamoxifen resistance

Therapies that target the synthesis of estrogen or the function of estrogen receptor(s) have been developed to treat breast cancer. While these approaches have proven to be beneficial to a large number of patients, both de novo and acquired resistance to these drugs is a significant problem. Recent advances in our understanding of the molecular mechanisms that contribute to resistance have provided a means to begin to predict patient responses to these drugs and develop rational approaches for combining therapeutic agents to circumvent or desensitize the resistant phenotype. Here, we review common mechanisms of antiestrogen resistance and discuss the implications for prediction of response and design of effective combinatorial treatments.

EGFR and Src are involved in indole-3-carbinol-induced death and cell cycle arrest of human breast cancer cells

Indole-3-carbinol (I3C), a dietary chemopreventive compound, induced marked reduction in epidermal growth factor receptor (EGFR) prior to cell death in cells representing three breast cancer subtypes. Signalling pathways, linking these events were investigated in detail. I3C modulated tyrosine phosphorylation from 30 min in four cell lines. In MDA-MB-468 and HBL100 cells, it induced Src activation after 5 h. In MDA-MB-468 cells, I3C induced signalling between 4.5 and 7 h, which involved sequential activation of Src, EGFR, STAT-1 and STAT-3, followed by EGFR degradation. It also induced physical association between activated Src and EGFR. In MCF7 and MDA-MB-231 cells, I3C modulated expression of cell cycle-related proteins, p21Cip1, p27Kip1, cyclin E, cyclin D1 and CDK6, with upregulation of p21Cip1 and cyclin E being dependent on Src. Inhibition of EGFR by specific inhibitors PD153035 or ZD1839 increased susceptibility to I3C-induced apoptosis of MCF7, MDA-MB-468 and MDA-MB-231 cells. Inhibition of Src sensitized MDA-MB-468 and MDA-MB-231 cells to I3C, whereas overexpression of c-Src increased resistance to I3C in MDA-MB-468 and HBL100 cells. Modulation of Src in MDA-MB-468 cells influenced the basal level of EGFR expression and cell viability; the latter being positively correlated with EGFR activation levels. Therefore, EGFR and Src activities are essential for I3C-induced cell cycle arrest and death; however, I3C-induced pathways depend on specific features of breast cancer cells. The cancer types, which rely on 'EGFR addiction' or Src deregulation, are likely to be susceptible to I3C.

Inhibition of intrahepatic bile duct dilation of the polycystic kidney rat with a novel tyrosine kinase inhibitor gefitinib

The polycystic kidney (PCK) rat represents a liver and kidney cyst pathology corresponding to Caroli's disease with congenital hepatic fibrosis and autosomal recessive polycystic kidney disease. We previously reported that an epidermal growth factor receptor tyrosine kinase inhibitor, gefitinib (Iressa), significantly inhibited the abnormal growth of biliary epithelial cells of PCK rats in vitro. This study investigated the effects of gefitinib on cyst pathogenesis of the PCK rat both in vitro and in vivo. A three-dimensional culture model of biliary epithelial cells in the collagen gel matrix was used for in vitro analysis. For in vivo experiments, PCK and control rats were treated with gefitinib between 3 and 10 weeks of age. In vitro, gefitinib had strong inhibitory effects on biliary cyst formation of PCK rats. In vivo, treatment with gefitinib significantly inhibited the cystic dilatation of the intrahepatic bile ducts of PCK rats, which was accompanied by improvement of liver fibrosis. By contrast, no beneficial effects were observed on renal cyst development because of the treatment. These results suggest that signaling pathways mediated by epidermal growth factor receptor are involved in biliary dysgenesis of the PCK rat, with the mechanisms of cyst progression being different between the liver and kidney.

What clinicians need to know about antioestrogen resistance in breast cancer therapy

Tamoxifen is the drug most used for early breast cancer treatment in oestrogen receptor (ER) positive patients. Unfortunately, despite high ER tumour levels in a tumour, resistance to endocrine therapy, either de novo or acquired after prolonged treatment, can occur. In this review, we will try to summarise the postulated mechanisms of hormonal-resistance, namely, the role of co-regulators and the crosstalk between the HER-2, IGF-IR, Cox-2 and ER pathways. Other predictive markers of tamoxifen-resistance/response, such as cyclin E and UPA/PAI-1, are also discussed.

Clinical efforts to combine endocrine agents with targeted therapies against epidermal growth factor receptor/human epidermal growth factor receptor 2 and mammalian target of rapamycin in breast cancer

Enhancing the benefit of endocrine therapy by overcoming de novo or acquired resistance remains an important goal in systemic breast cancer therapy. Progress continues to be made in elucidating the molecular pathways by which estrogen receptor-positive breast cancer cells escape from endocrine therapy. The increasing recognition of the roles of epidermal growth factor receptor (EGFR) and human EGFR2 in cross-talk activation of estrogen receptor signaling has led to studies aimed at identifying whether small-molecule tyrosine kinase inhibitors targeted against these receptors give additive or synergistic effects when combined with endocrine agents. Activation of the phosphatidylinositol-3-OH kinase/Akt pathway has also been associated with resistance to either tamoxifen or estrogen deprivation, and preclinical studies have shown that the mammalian target of rapamycin antagonist temsirolimus can restore endocrine sensitivity in breast cancer cells. Randomized phase II trials of aromatase inhibitors combined with EGFR/human EGFR2 tyrosine kinase inhibitors or mammalian target of rapamycin antagonists have been completed in both the neoadjuvant and advanced breast cancer settings. Larger phase III trials with both approaches are now in progress and have been powered to detect whether either strategy can significantly prolong time to disease progression compared with endocrine therapy alone. The correlation of molecular and clinical results from these ongoing studies will be important to establish appropriate biological variables for selecting those patients who may benefit most from this combined approach.

Fulvestrant ('Faslodex'): current and future role in breast cancer management

Fulvestrant ('Faslodex') is a new type of estrogen receptor antagonist with no agonist effects, that reduces cellular levels of both estrogen and progesterone receptors. Results from two Phase III trials showed that fulvestrant is at least as effective as the third-generation selective aromatase inhibitor anastrozole in postmenopausal women with advanced breast cancer following progression on antiestrogen therapy, indicating the potential for second-line fulvestrant in this setting. In clinical practice, fulvestrant is well tolerated, with good rates of clinical benefit observed as first-line therapy and following progression on prior endocrine agents. Other endocrine agents have been shown to have good clinical activity when resistance to fulvestrant has developed, showing that fulvestrant lacks cross-resistance with other treatments. Ongoing trials are investigating the efficacy of fulvestrant after failure on aromatase inhibitors and evaluating its use in combination with therapies that target growth factor receptor signaling pathways.

Additive antitumor effects of gefitinib and imatinib on anaplastic thyroid cancer cells

PURPOSE

Anaplastic thyroid cancer (ATC) is one of the most aggressive malignancies. Although multidisciplinary treatments have been introduced, patients with this disease rarely survive longer than 1 year. These findings prompted us to investigate the antitumor activity of molecular targeting agents in thyroid cancer cells.

METHODS

Two tyrosine kinase inhibitors, gefitinib and imatinib, were tested in a poorly differentiated thyroid cancer cell line, KTC-1, and two ATC cell lines, KTC-2 and KTC-3.

RESULTS

All cell lines expressed not only a target molecule of gefitinib, HER1, but also a cognate receptor, HER2. They also expressed target molecules of imatinib, c-ABL and platelet-derived growth factor receptors at various levels. Both agents had modest antitumor activity in these cell lines. Combined treatment with gefitinib and imatinib led to an additional antitumor effect. Each agent induced apoptosis and their combined treatment enhanced apoptosis associated with the down-regulation of antiapoptotic proteins, Bcl-2 and Bcl-xL. Moreover, their combined treatment additionally inhibited the growth of KTC-3 xenografts in nude mice.

CONCLUSIONS

These are the first findings to suggest that both gefitinib and imatinib have antitumor activity against ATC cells and that their combined use has greater activity than either drug alone.

The role of the epidermal growth factor receptor in breast cancer

Recent trials of drug therapy targeting the erbB receptor HER2 have met with success in breast cancer. The epidermal growth factor receptor or EGFR is a closely related receptor from this same family that is involved in cellular signal transduction and tumor cell growth and survival. Emerging evidence indicates that EGFR is implicated in the development of hormone-resistant breast cancer, and that its activity is intertwined with estrogen receptor. Here, the role of EGFR in breast cancer is reviewed, and data from selected clinical trials of signal transduction inhibition of this cellular target are summarized.

Biological characteristics of the pure antiestrogen fulvestrant: overcoming endocrine resistance

Understanding the underlying mechanisms responsible for endocrine resistance remains a challenge in improving the treatment of breast cancer. The discovery that growth factor and estrogen receptor (ER) signaling pathways interact in endocrine resistant breast cancer has provided a rationale for disrupting these signaling cascades in ER-positive, endocrine-resistant tumors. In postmenopausal women, the ER signaling pathway may be targeted using fulvestrant ('Faslodex'), a new type of ER antagonist with no agonist effects. Fulvestrant binds, blocks and causes degradation of the ER, culminating in complete abrogation of estrogen-sensitive gene transcription. This unique mechanism of action may result in a lack of cross-resistance with other endocrine agents. Preclinical studies have confirmed the potential of fulvestrant to inhibit the growth of tamoxifen-resistant, as well as tamoxifen-sensitive, human breast cancer cell lines. Clinical studies have demonstrated that fulvestrant is an effective treatment option in postmenopausal women with advanced breast cancer who have progressed on prior endocrine therapy. Furthermore, preclinical studies indicate that combining fulvestrant with growth factor targeted agents, such as the epidermal growth factor receptor (EGFR/HER1) tyrosine kinase inhibitor gefitinib (IRESSA) or the anti-human HER2 monoclonal antibody trastuzumab ('Herceptin'), may result in greater anti-tumor activity than either agent alone. A range of clinical trials are now ongoing to determine whether the combination of growth factor-targeting agents with fulvestrant will delay the onset of endocrine resistance and so provide new strategy for women with hormone receptor-positive advanced breast cancer.

Resistance to endocrine therapy in breast cancer

Endocrine therapy is the treatment of choice for patients with breast cancer expressing estrogen receptor (ER) and/or progesterone receptor. The efficacy of endocrine therapy is well established in the prevention, adjuvant and metastatic settings. However, either de novo or acquired resistance is frequently observed. Much effort has been made to elucidate the mechanisms of action underlying resistance to endocrine therapy in breast cancer, and several possible explanations have been suggested. Our previous studies have indicated that combined treatment with an antiestrogen, fulvestrant, and an inhibitor of the HER2 signaling pathway, trastuzumab, or an inhibitor of the HER1 signaling pathway, gefitinib, leads to an additive antitumor effect in breast cancer cells expressing ER and HER2 or HER1, respectively. It has also been suggested that the HER1 or HER2 signaling pathway is upregulated during the development of antiestrogen-resistant growth in breast cancer cells. These findings suggest that signal transduction inhibitors are effective for the treatment of antiestrogen-resistant breast cancer. A hypoxic microenvironment has been shown to promote malignant progression in cancer cells. Our previous study and others have suggested that hypoxia posttranscriptionally reduces ER expression and decreases sensitivity to hormonal agents in breast cancer cells. Our preliminary study has also shown that a hypoxic cytotoxin, tirapazamine, increases ER expression in breast cancer xenografts. Differential antitumor activity of tirapazamine on tumor cells under normoxic or hypoxic conditions may cause this phenomenon. These findings suggest that hypoxic cytotoxins may retard the development of endocrine resistance induced by hypoxia. Molecular mechanisms responsible for endocrine resistance in breast cancer are reviewed and possible therapeutic strategies against this resistance are discussed.

Gefitinib (IressaTM, ZD1839) and Tyrosine Kinase Inhibitors

Targeted therapies are one of the latest innovative trends in cancer therapy. The epidermal growth factor receptor (EGFR) is a target found in high concentrations in several solid tumors including lung, breast, colorectal, and brain. Tyrosine kinase inhibitors, such as gefitinib (Iressa, ZD1839), block the EGFR. As a result, there is inhibition of cellular proliferation, promotion of apoptosis, and inhibition of anti-angiogenesis. Gefitinib has demonstrated significant efficacy in non-small-cell lung cancer (NSCLC), leading to FDA approval for treatment of this refractory disease. Phase 2 trials with gefitinib for platinum refractory NSCLC reported disease response and symptom improvement. Early results of phase 2 studies of gefitinib, combined with standard chemotherapy in colorectal cancer, showed a 75% response rate compared with 55% with standard therapy alone. Gefitinib, combined with flutamide, produced an additive growth inhibition in prostate cancer. A phase 2 trial of gefitinib in first-relapse glioblastoma multiforme demonstrated median overall survival from treatment start of 39.4 weeks compared with 40 weeks with standard chemotherapy. Gefitinib is an oral agent with a mild toxicity profile, and thus, may be an optimal addition to chemotherapeutic regimens for some solid tumors. Gefitinib is potentially a vital and useful weapon in the arsenal of cancer therapies.

Metaplastic breast carcinomas are negative for Her-2 but frequently express EGFR (Her-1): potential relevance to adjuvant treatment with EGFR tyrosine kinase inhibitors?

BACKGROUND

Metaplastic carcinomas (MCs) of the breast rarely express steroid receptors and Her-2, which minimises the options for adjuvant treatment in patients with advanced disease.

AIMS

To investigate the possible eligibility of patients with MCs for epidermal growth factor receptor (EGFR) targeted treatment.

METHODS

Immunohistochemical assessment of the expression of steroid receptors and four members of the EGFR/Her family (EGFR/Her-1-4) in 20 MCs (eight with heterologous elements, seven spindle cell MCs, four carcinosarcomas, and one matrix producing carcinoma). Fourteen of the 20 MCs were positive for EGFR (Her-1). Among these cases, 1+, 2+, and 3+ reactivity were seen in two, four, and eight cases, respectively. Her-2 was only present in one MC with 1+ reactivity. Her-3 (1+ reactivity), Her-4 (2+ reactivity), and the androgen receptor (2+ reactivity) were also expressed by one tumour. Oestrogen and progesterone receptors (3+ reactivity each) were detected in the epithelial component only of two carcinosarcoma-type MCs.

CONCLUSIONS

MCs express EGFR considerably more frequently than the types of breast carcinomas that have been investigated previously. Although molecular analyses for possible genetic alterations in the EGFR might be required, these results suggest that women suffering from this aggressive form of breast carcinoma might benefit from treatment with protein kinase inhibitors, such as gefitinib.

A multicentre phase II study on gefitinib in taxane- and anthracycline-pretreated metastatic breast cancer

BACKGROUND

Epidermal growth factor receptor (EGFR) is considered to be a viable drug target in a variety of solid tumors. The clinical benefit and safety of the EGFR tyrosine kinase inhibitor gefitinib ('Iressa')1 was evaluated in this Phase II, multicentre study of patients with taxane and anthracycline pretreated, metastatic breast cancer.

METHODS

Gefitinib (500 mg/day) was given to 58 patients until disease progression. Primary endpoint was the clinical response rate to the study treatment.

RESULTS

One patient (1.7%) had objective partial tumor response of her liver and pleural metastasis. Fifty-seven patients (98.3%) were non-responders with 52 patients (89.7%) having progressive disease and five patients (8.6%) were not evaluable. Two patients reported a significant improvement in pain at metastatic sites (1 liver, 1 bone). The median time to progression was 61 days (95% CI : 54-82 days) and the proportion of patients alive and progression free at 6 months at trial closure was 1.8% (95% CI : 0.0-5.2%). The median survival time was 357 days (95% CI : 257-441 days). Fifty-four patients (93.1%) discontinued study medication prematurely due to disease progression and three (5.2%) due to adverse events (diarrhea, pruritus, peripheral edema).

CONCLUSIONS

Gefitinib monotherapy at 500 mg daily did not appear to be efficacious in the treatment of heavily pretreated metastatic breast cancer patients. It was well tolerated and the side effect profile was as expected from current knowledge of the drug. There was no correlation between EGFR expression and response in this study.

Combined targeting of the estrogen receptor and the epidermal growth factor receptor in non-small cell lung cancer shows enhanced antiproliferative effects

Identifying new effective therapeutic treatments for lung cancer is critical to improving overall patient survival. We have targeted both the estrogen receptor (ER) and the epidermal growth factor receptor (EGFR) pathways using an ER antagonist, fulvestrant ("Faslodex"), and the selective EGFR tyrosine kinase inhibitor, gefitinib ("Iressa"), in non-small cell lung cancer (NSCLC) cells. Rapid activation of phospho-EGFR and phospho-p44/p42 mitogen-activated protein kinase by estrogen was observed, indicating nonnuclear ER transactivation of EGFR. Additionally, EGFR protein expression was down-regulated in response to estrogen and up-regulated in response to fulvestrant in vitro, suggesting that the EGFR pathway is activated when estrogen is depleted in NSCLC cells. Cell growth and apoptosis were examined in several NSCLC lines that express varying amounts of ERbeta, EGFR, and Neu but no full-length ERalpha. One cell line contained an EGFR mutation. Cells were exposed to 10 nmol/L estrogen and 10 ng/mL EGF and either 1 mumol/L fulvestrant or 1 mumol/L gefitinib alone or in combination. In all cell lines, the drug combination decreased cell proliferation up to 90% and increased apoptosis 2-fold. The relative responses to gefitinib and fulvestrant were similar regardless of ER and EGFR expression and mutation status. In an in vivo lung tumor xenograft model, the drug combination decreased tumor volume in severe combined immunodeficient mice by approximately 60% compared with 49% and 32% for gefitinib and fulvestrant treatment alone, respectively. Antitumor effects of the combination therapy were accompanied by biochemical and histologic evidence of increased apoptosis, decreased phospho-p44/p42 mitogen-activated protein kinase expression, and increased Ki-67 expression compared with individual treatment. These studies provide evidence of a functional interaction between the ER and the EGFR pathways in NSCLC.

Endometrial Stromal Sarcomas Frequently Express Epidermal Growth Factor Receptor (EGFR, HER-1)

Endometrial stromal sarcomas are rare malignant mesenchymal uterine tumors. The expressions of different epidermal growth factor receptors such as EGFR (HER-1), HER-2, HER-3, and HER-4 have not yet been examined in these tumors. Twenty-three cases of endometrial sarcomas consisting of 20 low-grade endometrial stromal sarcomas and 3 undifferentiated endometrial sarcomas were examined immunohistochemically for EGFR (HER-1), HER-2, HER-3, and HER-4. EGFR (HER-1) was positive in 17 of 23 (74%) cases. While the three undifferentiated endometrial sarcomas were positive for EGFR, 14 of 20 (70%) low-grade endometrial stromal sarcomas showed positive reactions for EGFR. All examined cases were negative for HER-2, HER-3, and HER-4. This study is the first to show common expression of EGFR (HER-1) in endometrial stromal sarcomas. This finding may provide the basis for a new therapeutic strategy using monoclonal antibodies against EGFR (such as cetuximab) or small molecule inhibitors of EGFR (such as gefitinib) in patients with endometrial sarcomas.

Current and Future Perspectives on Fulvestrant

Fulvestrant, an estrogen receptor antagonist with no known agonist effects, is effective and well tolerated in the treatment of hormone-sensitive breast cancer after antiestrogen failure in postmenopausal women. Numerous phase II and III clinical trials of fulvestrant that are designed to build on its efficacy in breast cancer and explore its value in other tumors are ongoing or in the final planning stage. Favorable safety, dose-response, and pharmacokinetic data led to the initiation of clinical trials to evaluate loading and higher doses with the aim of building on the well-defined efficacy of fulvestrant. Recently reported results of phase II trials by the North Central Cancer Treatment Group and the Swiss Group for Clinical Cancer Research support the clinical activity of fulvestrant after recurrence or progression on a nonsteroidal aromatase inhibitor, and 2 international phase III trials are ongoing in this setting. As a first-line treatment for metastatic disease, fulvestrant is currently being evaluated in combination with anastrozole versus anastrozole alone in 2 phase III trials, 1 by the Southwest Oncology Group and the other being conducted mainly in Scandinavia. Preclinical data have also led to randomized phase II trials of fulvestrant in combination with the epidermal growth factor receptor tyrosine kinase inhibitor, gefitinib, and the HER2/neu-targeted antibody trastuzumab. Additional phase II and III trials are currently evaluating fulvestrant plus tipifarnib, Theratope vaccine, or the dual kinase inhibitor, GW572016. Although fulvestrant is undergoing robust clinical development as a treatment for breast cancer, investigation of this agent in other types of solid tumors has only just begun.

Targeting the epidermal growth factor receptor by gefitinib for treatment of hepatocellular carcinoma

BACKGROUND/AIMS

Hepatocellular carcinoma (HCC) is one of the most common cancer-related causes of death worldwide. Due to very poor 5-year-survival new therapeutic approaches are mandatory. Gefitinib, an inhibitor of epidermal growth factor receptor tyrosine kinase (EGFR-TK), potently suppresses the growth of various tumors, but its effect on HCC remains unexplored. We therefore studied the antineoplastic potency of gefitinib in human HCC cells.

RESULTS

Gefitinib induced a time- and dose-dependent growth inhibition of the human HCC cell lines Huh-7 and HepG2. Gefitinib-treatment induced both mitochondria-dependent and -independent apoptosis. Changes in mitochondrial membrane potential and caspase-8 activation, followed by caspase-3 activation and nuclear degradation, were detected. Moreover, gefitinib induced cell cycle arrest at the G1/S checkpoint and decreased the phosphorylation of mitogen-activated protein kinase ERK1/2. Finally, gefitinib suppressed the expression of antiapoptotic Bcl-2 and Bcl-X(L), further rendering HCC cells prone to apoptosis.

CONCLUSIONS

Our data demonstrate that the inhibition of EGFR-TK by gefitinib induced growth inhibition, apoptosis and cell cycle arrest in human HCC cells. Thus, EGFR-TK inhibition appears to be a promising novel approach for future treatment strategies of HCC.

Gefitinib--a novel targeted approach to treating cancer

Twenty years after the epidermal growth factor receptor (EGFR) was identified as a potential anticancer target, the EGFR inhibitor gefitinib (Iressa; AstraZeneca) has been approved for the treatment of patients with advanced non-small-cell lung cancer in many countries. Studies have indicated its potential for treating patients with other types of solid tumours. Investigation of gefitinib has not only increased our knowledge about the biology of EGFR signalling, but is contributing to our evolving understanding of which tumours are EGFR dependent.