Prognostic relevance of activated Akt kinase in node-negative breast cancer: a clinicopathological study of 99 cases

(2E)-2-Benzylidene-4,7-dimethyl-2,3-dihydro-1H-inden-1-one (MLT-401), a novel arylidene indanone derivative, scavenges free radicals and exhibits antiproliferative activity of Jurkat cells

Background

The arylidene indanone scaffold has contributed many lead molecules in chemotherapeutic anticancer agent research.

Objectives

To determine the oxidant-scavenging activities and antiproliferative activity of (2E)-2-benzylidene-4,7-dimethyl-2,3-dihydro-1H-inden-1-one (MLT-401), an arylidene indanone derivative.

Methods

Jurkat cells, primary lymphocytes, and Vero cells were treated with MLT-401. Antioxidant properties of MLT-401 were determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH)-based, 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS)-based, and ferric-reducing antioxidant potential (FRAP) assays. Inhibition of cell proliferation was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-based assay. Nuclear status was determined using a DNA fragmentation assay, and cell cycle stage was analyzed by flow cytometry. Mitochondrial membrane enzyme activities were measured using colorimetric methods.

Results

The antioxidant assays gave MLT-401 half maximal inhibitory concentration (IC50) values of 1611 nM (DPPH-based assay), 2115 nM (ABTS-based assay), and 1586 nM (FRAP assay). MLT-401 inhibited proliferation of Jurkat cells with a concentration for 50% of maximal inhibition of cell proliferation (GI50) of 341.5 nM, being 12- and 9-fold less than GI50 concentrations for normal lymphocytes and Vero cells, respectively. MLT-401 caused nuclear fragmentation and DNA laddering as seen by electrophoresis. Jurkat cells showed a time-dependent accumulation of sub G0/G1 cells after MLT-401 treatment. Mitochondrial membrane-bound Na+/K+ ATPase, Ca2+ ATPase, and Mg2+ ATPase activities were inhibited by MLT-401 in a dose-dependent manner.

Conclusion

MLT-401 possesses significant antiproliferative activity and scavenges free radicals released through mitochondrial membrane damage in a Jurkat cell line model of cancer cells. Further investigation of MLT-401 as a chemotherapeutic anticancer agent and development of other arylidene indanone analogues are warranted. A detailed elucidation of mechanistic pathways is required for further development.

Distinct functions of AKT isoforms in breast cancer: a comprehensive review

BACKGROUND

AKT, also known as protein kinase B, is a key element of the PI3K/AKT signaling pathway. Moreover, AKT regulates the hallmarks of cancer, e.g. tumor growth, survival and invasiveness of tumor cells. After AKT was discovered in the early 1990s, further studies revealed that there are three different AKT isoforms, namely AKT1, AKT2 and AKT3. Despite their high similarity of 80%, the distinct AKT isoforms exert non-redundant, partly even opposing effects under physiological and pathological conditions. Breast cancer as the most common cancer entity in women, frequently shows alterations of the PI3K/AKT signaling.

MAIN CONTENT

A plethora of studies addressed the impact of AKT isoforms on tumor growth, metastasis and angiogenesis of breast cancer as well as on therapy response and overall survival in patients. Therefore, this review aimed to give a comprehensive overview about the isoform-specific effects of AKT in breast cancer and to summarize known downstream and upstream mechanisms. Taking account of conflicting findings among the studies, the majority of the studies reported a tumor initiating role of AKT1, whereas AKT2 is mainly responsible for tumor progression and metastasis. In detail, AKT1 increases cell proliferation through cell cycle proteins like p21, p27 and cyclin D1 and impairs apoptosis e.g. via p53. On the downside AKT1 decreases migration of breast cancer cells, for instance by regulating TSC2, palladin and EMT-proteins. However, AKT2 promotes migration and invasion most notably through regulation of β-integrins, EMT-proteins and F-actin. Whilst AKT3 is associated with a negative ER-status, findings about the role of AKT3 in regulation of the key properties of breast cancer are sparse. Accordingly, AKT1 is mutated and AKT2 is amplified in some cases of breast cancer and AKT isoforms are associated with overall survival and therapy response in an isoform-specific manner.

CONCLUSIONS

Although there are several discussed hypotheses how isoform specificity is achieved, the mechanisms behind the isoform-specific effects remain mostly unrevealed. As a consequence, further effort is necessary to achieve deeper insights into an isoform-specific AKT signaling in breast cancer and the mechanism behind it.

Association between RNF2+P-AKT expression in pretreatment biopsy specimens, and poor survival following radiotherapy in patients with esophageal squamous cell carcinoma

The protein expression levels of Ring finger protein 2 (RNF2) and phosphor-protein kinase B (P-AKT) were determined in esophageal squamous cell carcinoma (ESCC) tissues, and the association between patient clinicopathological characteristics and survival time following definitive intensity-modulated radiotherapy was assessed. Cancerous biopsy tissues were collected from patients with ESCC at The Fourth Affiliated Hospital of Hebei Medical University between January 2010 and December 2013. Of these 99 cases, 83 were used to analyze the protein expression level of RNF2 (89.2% positive), 85 for P-AKT (65.9% positive) and 80 for RNF2+P-AKT protein expression levels (62.5% both positive). The expression levels of RNF2 protein in ESCC were associated with tumor volume (P=0.024), whilst those of P-AKT and RNF2+PAKT were associated with sex (P=0.041 and P=0.003, respectively). There were no significant differences in overall survival (OS) or progression-free survival (PFS) rate between the RNF2^- and the RNF2^+-+++ groups (P=0.134 and P=0.366, respectively), or between the P-AKT^- group and P-AKT^+-+++ group (P=0.468; P=0.580, respectively). The 1-, 3- and 5-year OS rates were 68.0, 28.0, and 20.0%, and 86.7, 53.3, and 31.1%, in the RNF2/P-AKT⁺ group and Other group, respectively (χ²=4.205; P=0.040). Multivariate analysis revealed that age, T stage and RNF2+P-AKT expression were independent prognostic factors for ESCC (P=0.010, P=0.008 and P=0.010, respectively). The expression of RNF2+P-AKT combined was an independent prognostic factor affecting survival rate, and therefore presents a potential prognostic indicator for patients with ESCC, treated with definitive radiotherapy.

FCY-302, a Novel Small Molecule, Induces Apoptosis in Leukemia and Myeloma Cells by Attenuating Key Antioxidant and Mitochondrial Enzymes

Arylidene analogs are well proven for biological activities. FCY-302, a novel small molecule belonging to this class, was screened for its biological efficacy in leukemia and myeloma cells. FCY-302 selectively inhibited proliferation of cancer cells with GI₅₀ values of 395.2 nM, 514.6 Nm, and 642.4 nM in HL-60, Jurkat, and RPMI-8226 cells, respectively. The compound also increased sub-G₀ peak in the cancer cell cycle and favored apoptosis determined by annexin V assay. The compound decreased the antiapoptotic Bcl-2 levels and increased proapoptotic Bax proteins in leukemia and myeloma cell lines. FCY-302 attenuated the mitochondrial membrane-bound Na⁺/K⁺ ATPase, Ca²⁺ ATPase, and Mg²⁺ ATPase enzyme activities and significantly decreased activities of antioxidant enzymes like SOD, CAT, G_R, and GST in all the three cancer cells tested. Our findings suggest that FCY-302 inhibits the proliferation of leukemia and myeloma cancer cells by altering key mitochondrial and antioxidant enzymes, eventually driving them to apoptosis. These results drive focus on FCY-302 and its analogs to be developed as potential small molecules with bioactivities against cancer.

Phosphorylated Akt1 in Human Breast Cancer Measured by Direct Sandwich Enzyme-Linked Immunosorbent Assay: Correlation with Clinicopathological Features and Tumor VEGF-Signaling System Component Levels

Protein kinase B (Akt) plays a major role in the regulation of breast cancer growth, survival, hormone, drug and radiosensitivity, but the clinical value of its expression and activation in human tumors is unclear. Activated Akt1 (pAkt1) expression was quantified in a series of 46 breast cancer and adjacent mammary gland samples by a direct Path-Scan™ PhosphoAkt1 (Ser473) sandwich ELISA kit. VEGF, sVEGFR1 and sVEGFR2 levels were measured simultaneously by standard ELISA kits. Forty-nine percent of the tumors had an increased pAkt1 level as compared to adjacent tissue. pAkt1 levels were significantly higher in stage IIb than in stage I-IIa tumors. The frequency of pAkt1 elevation was positively associated with tumor size and malignancy grade. pAkt1 was also twice as frequently increased in PgR-negative as in PgR-positive tumors, while its mean level was significantly higher in ER-positive than in ER-negative tumors. VEGF, sVEGFR1 and sVEGFR2 were increased in 73–85% of the tumors, but no associations with most clinicobiological factors and pAkt1 level were found. In conclusion, activation of Akt1 is not associated with VEGF signaling protein expression in breast cancer but is related to tumor size, grade of malignancy, and steroid receptor status.

AKT Hyperactivation and the Potential of AKT-Targeted Therapy in Diffuse Large B-Cell Lymphoma

AKT signaling is important for proliferation and survival of tumor cells. The clinical significance of AKT activation in diffuse large B-cell lymphoma (DLBCL) is not well analyzed. Here, we assessed expression of phosphorylated AKT (p-AKT) in 522 DLBCL patients. We found that high levels of p-AKT nuclear expression, observed in 24.3% of the study cohort, were associated with significantly worse progression-free survival and Myc and Bcl-2 overexpression. However, multivariate analysis indicated that AKT hyperactivation was not an independent factor. miRNA profiling analysis demonstrated that 63 miRNAs directly or indirectly related to the phosphatidylinositol 3-kinase/AKT/mechanistic target of rapamycin pathway were differentially expressed between DLBCLs with high and low p-AKT nuclear expression. We further targeted AKT signaling using a highly selective AKT inhibitor MK-2206 in 26 representative DLBCL cell lines and delineated signaling alterations using a reverse-phase protein array. MK-2206 treatment inhibited lymphoma cell viability, and MK-2206 sensitivity correlated with AKT activation status in DLBCL cells. On MK-2206 treatment, p-AKT levels and downstream targets of AKT signaling were significantly decreased, likely because of the decreased feedback repression; Rictor and phosphatidylinositol 3-kinase expression and other compensatory pathways were also induced. This study demonstrates the clinical and therapeutic implications of AKT hyperactivation in DLBCL and suggests that AKT inhibitors need to be combined with other targeted agents for DLBCL to achieve optimal clinical efficacy.

Phosphosite-Specific Antibodies: A Brief Update on Generation and Applications

Phosphate addition is a posttranslational modification of proteins, and this modification can affect the activity and other properties of intracellular proteins. Different animal species can be used to generate phosphosite-specific antibodies as either polyclonals or monoclonals, and each approach offers its own benefits and disadvantages. The validation of phosphosite-specific antibodies requires multiple techniques and tactics to demonstrate their specificity. These antibodies can be used in arrays, flow cytometry, and imaging platforms. The specificity of phosphosite-specific antibodies is vital for their use in proteomics and profiling of disease.

AIB1 Genomic Amplification Predicts Poor Clinical Outcomes in Female Glioma Patients

Amplified in breast cancer 1 (AIB1) gene, a coactivator for steroid receptor, is frequently amplified in diverse cancers and is considered as an oncogene in tumorigenesis. However, the prognostic significance of AIB1 amplification in gliomas remains totally unclear. In this study, 115 gliomas and 16 benign meningiomas as control subjects were enrolled, and the copy number of AIB1 was analyzed in these samples. In addition, we explored potential correlation of AIB1 amplification with clinicopathological characteristics and clinical outcomes of glioma patients. Our data showed that glioma samples exhibited a significantly higher AIB1 copy number than control subjects as determined by quantitative polymerase chain reaction (qPCR) approach. Moreover, univariate analysis showed that AIB1 amplification (≥3.5 copies) was strongly correlated with cancer-related death (P =0.03). Interestingly, our data revealed a significant association of AIB1 amplification with WHO grade (P =0.03), tumor recurrence (P =0.03) and survival status (P =0.03) in female patients but not in male patients. Multivariate analysis further demonstrated that AIB1 amplification was independent factor for cancer-related death in female patients. Importantly, AIB1 amplification was closely relevant to worse survival in female patients (P =0.001), but not in male patients (P =1.00). In addition, the patients with AIB1 amplification were resistant to radiotherapy. Altogether, our data demonstrate that AIB1 amplification is a common genetic event in glioma tumorigenesis, and suggest that AIB1 amplification is not only a prognostic factor for poor clinical outcomes in glioma patients, but also a predictor of radiotherapy resistance in gliomas.

High EGFR and low p-Akt expression is associated with better outcome after nimotuzumab-containing treatment in esophageal cancer patients: preliminary clinical result and testable hypothesis

The epidermal growth factor receptor (EGFR) is widely overexpressed in esophageal squamous cell carcinoma (ESCC) and it results is associated with a poor prognosis. Identifying the subgroup of ESCC patients who are sensitive to EGFR-targeted therapy is a key point to facilitate its medical use.

We retrospectively analyzed 32 ESCC patients treated with the combination of nimotuzumab (h-R3) and radiotherapy (RT) or chemoradiotherapy (CRT). Expression of EGFR and phosphorylated proteins associated with EGFR signaling pathway, i.e. p-Akt and p-Erk, were assessed with immunohistochemistry (IHC) for all patients. Correlations between these proteins' expression levels and overall survival (OS) were assessed.

High expression of EGFR, p-Akt and p-Erk was detected in 53.1% (17/32), 54.8% (17/31) and 59.4% (19/32) of tumors respectively. No significant differences in OS were found between high EGFR, p-Akt and p-Erk expression groups and their respective counterparts. Of note, significantly better overall survival was observed in patients with coexistence of high EGFR expression and low p-Akt expression (p = 0.030).

Our data allowed us to put forward a hypothesis that high EGFR and low p-Akt expression may predict a clinical benefit of EGFR antagonists such as nimotuzumab combined with RT or CRT. This can be discussed in the terms of oncogene addiction and synthetic lethality concepts. This hypothesis can be further tested in larger groups of patients.

Targeting Phosphatidylinositide3-Kinase/Akt pathway by BKM120 for radiosensitization in hepatocellular carcinoma

Tumor control of hepatocellular carcinoma by radiotherapy remains unsatisfactory. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway plays a critical role in inhibiting cancer cell death. Elevated PI3K/Akt activity is associated with increased cellular resistance to irradiation. Our aim was to determine whether the inhibition of PI3K/Akt activity by a PI3K inhibitor, BKM120, contributes to the increased sensitivity of liver cancer cells to irradiation. The hepatocellular carcinoma cell lines (Huh7 and BNL) were used to evaluate the in vitro synergism between BKM120 and irradiation. Balb/c mice bearing ectopic BNL xenografts were treated with BKM120 and/or radiotherapy to assess the in vivo response. BKM120 increased cell killing by radiation, increased the expression of apoptotic markers, and suppressed the repair of radiation-induced DNA double-strand breaks. BKM120 pretreatment inhibited radiation-induced Akt phosphorylation and enhanced the tumor-suppressive effect and radiation-induced tumor cell apoptosis in ectopic xenografts. Inhibition of mTOR phosphorylation by rapamycin enhanced the radiosensitivity of BKM120-treated hepatocellular carcinoma cells. The synergism between BKM120 and irradiation likely inhibits the activation of Akt by radiation, leading to increased cell apoptosis and suppression of DNA-double-strand breaks repair in hepatocellular carcinoma cells. These data suggest that the BKM120/radiation combination may be a strategy worthy of clinical trials.

Detection of pAkt protein in imprint cytology of invasive breast cancer: Correlation with HER2/neu, hormone receptors, and other clinicopathological variables

Purpose:

Akt is a serine/threonine protein kinase and has emerged as a crucial regulator of widely divergent cellular processes, including apoptosis, proliferation, differentiation, and metabolism. Activation of Akt/protein kinase B has been positively associated with human epidermal growth-factor receptor 2 (HER2)/neu overexpression in breast carcinoma and a worse outcome among endocrine treated patients. The Akt signaling pathway currently attracts considerable attention as a new target for effective therapeutic strategies. We therefore investigated the relationship between activation of Akt and clinicopathologic variables including hormone receptor and HER2/neu status.

Methods:

Archival tumor tissues from 100 patients with invasive breast carcinoma were analyzed by immunocytochemistry. This study describes the results of immunocytochemical pAkt expression in breast carcinoma imprints, prepared from cut surfaces of freshly removed tumors. Both nuclear and cytoplasmic expressions were evaluated for pAkt.

Results:

Nuclear and cytoplasmic positive scores of 72% (72/100) and 42% (42/100), respectively, were found. Coexistence of nuclear and cytoplasmic staining was observed in 32 cases (32/100). Nuclear positive staining correlated with HER2/neu overexpression (P = 0.043) and was significantly associated with positive involvement of axillary lymph nodes (P = 0.013). No correlation was found between cytoplasmic pAkt rate and clinicopathological parameters, estrogen receptor, progesterone receptor or HER2/neu expression.

Conclusions:

pAkt expression can be evaluated in cytological material and may add valuable information to current prognostic models for breast cancer. pAkt overexpression appears to be linked with potentially aggressive tumor phenotype in invasive breast carcinoma.

Clinical significance of pAkt and pErk1/2 expression in early-stage breast cancer patients treated with anthracycline-based adjuvant chemotherapy

The expression of phosphorylated Akt (pAkt) and phosphorylated extracellular-regulated kinase 1/2 (pErk1/2) proteins may result in breast cancer progression and drug resistance in vitro, however, compelling evidence regarding the clinical significance of pAkt and pErk1/2 in early-stage breast cancer is currently lacking. Thus, the aim of the present study was to determine the prognostic value of pAkt and pErk1/2 expression in early-stage breast cancer patients treated with anthracycline-based adjuvant chemotherapy. Tumor specimens were obtained from 256 patients with early-stage breast cancer who had been treated with anthracycline-based adjuvant chemotherapy, and pAkt and pErk1/2 protein expression was immunohistochemically determined. The interactions between pAkt, pErk1/2 and clinical characteristics were assessed by performing χ² tests, and survival functions were estimated using the Kaplan-Meier method. It was identified that pAkt and pErk1/2 were expressed in 38.7 and 33.6% of patients, respectively, and that pAkt protein expression was correlated with pErk1/2 protein expression (P<0.001). In addition, after a median follow-up period of 52.5 months, the patients with pAkt- and pErk1/2-negative tumors experienced a significantly longer disease-free survival (DFS) time compared with pAkt- or pErk1/2-positive patients (P=0.028). pErk1/2 expression was associated with the decreased DFS time of the patients (P=0.049), and pAkt and pErk1/2 expression were associated with the decreased DFS time in human epidermal growth factor receptor (HER2)-positive patients (P=0.002). pErk1/2 expression was associated with chemotherapy resistance (P=0.016). Thus, the coexpression of pAkt and pErk1/2 was an independent factor for a poor prognosis in early-stage and HER2-positive breast cancer patients. By contrast, pErk1/2 expression alone may be a poor predictor for determining the efficacy of anthracycline-based chemotherapy.

Clinical value of isoform-specific detection and targeting of AKT1, AKT2 and AKT3 in breast cancer

SUMMARY 

Overactivation of the PI3K/AKT signaling pathway is frequently reported in breast cancer, consequently inhibitors targeting this pathway are clinically useful. AKT constitutes a hub in the regulation of several cancer hallmarks, such as proliferation, survival and migration. Three AKT isoforms, named AKT1, AKT2 and AKT3, are identified in humans. AKT alterations, mainly upregulation of phosphorylated AKT in tumors may have prognostic and predictive value. Moreover, the AKT isoforms may possess partly divergent cellular functions and be upregulated in certain breast cancer subtypes, suggesting the importance of isoform-specific analyses. In conclusion, AKT isoform-specific detection and targeting in different tumor subtypes will hopefully result into a further developed personalized medicine.

The impact of activated p-AKT expression on clinical outcomes in diffuse large B-cell lymphoma: a clinicopathological study of 262 cases

BACKGROUND

Oncogenic phosphatidylinositol-3-kinase/serine-threonine kinase (PI3K/AKT) pathway plays a critical role in cell proliferation and growth. Phosphorylated AKT (p-AKT) has been reported to be abnormally overexpressed and to have poor prognostic impact in solid tumors.

PATIENTS AND METHODS

To define the clinical implications of p-AKT expression in diffuse large B-cell lymphoma (DLBCL), we calculated arbitrary units (AUs) by multiplying the intensity and the proportion of p-AKT expression and investigated the impact of p-AKT expression on clinical outcomes. We assessed 262 patients with DLBCL. Based on a cutoff value of the upper limit of the third quartile of AUs, 56 patients were classified as high p-AKT and the remaining 206 patients were classified as low p-AKT.

RESULTS

The high p-AKT group was closely associated with more advanced stage (stage III-IV, P = 0.02), two or more extranodal involvement (P = 0.03), lactic dehydrogenase elevation (P = 0.03), higher International Prognostic Index risk groups (high intermediate/high, P = 0.02), and the presence of B-symptoms (P = 0.01). The high p-AKT group showed substantially worse overall survival (OS) (median OS, 115.0 months versus not reached, P = 0.004) and progression-free survival (PFS) (median PFS, 25.5 versus 105.8 months, P = 0.019) compared with the low p-AKT group. Multivariate analysis revealed that high p-AKT expression retained its significant poor prognostic impact for OS (hazard ratio 1.7; 95% confidence interval, 1.0-2.7; P = 0.031). The subgroup with high p-AKT expression and concurrent Epstein-Barr virus positivity showed worst prognosis with the median OS and PFS of 15.2 and 7.4 months.

CONCLUSION

DLBCL patients with high p-AKT expression showed distinct clinical features and followed a more rapidly deteriorating clinical course with worse OS and PFS. Thus, a more effective treatment option should be developed for this subset of DLBCL patients, and targeting PI3K/AKT pathway may be a promising therapeutic strategy.

Expression of the Androgen Receptor, pAkt, and pPTEN in Breast Cancer and Their Potential in Prognostication

BACKGROUND

Importance of androgen receptor (AR) as an independent prognostic marker in Pakistani women with breast cancer (BCa) remains unexplored. Our aim was to identify the expression and potential prognostic value of AR, its upstream regulator (pAkt) and target gene (pPTEN) in invasive BCa.

METHODS

This study used a cohort of 200 Pakistani women with invasive BCa diagnosed during 2002-2011. Expression of AR, pAkt and pPTEN was determined on formalin fixed paraffin embedded tissue sections by immunohistochemistry. The association of AR, pAkt and pPTEN with clinicopathological parameters was determined. Survival analyses were undertaken on patients with ≥5years of follow-up (n=82).

RESULTS

Expression of AR, pAkt and pPTEN was observed in 47.5%, 81.3% and 50.6% of patients, respectively. AR-expressing tumors were low or intermediate in grade (P<.001) and expressed ER (P=.002) and PR (P=.001). Patients with AR+ tumors had significantly higher OS (Mean OS=10.2±0.465years) compared to patients with AR- tumors (Mean OS=5.8±0.348years) (P=.047). Furthermore, AR-positivity was associated with improved OS in patients receiving endocrine therapy (P=.020). Patients with AR+ /pAkt+ /pPTEN- tumors, had increased OS (Mean OS=7.1±0.535years) compared to patients with AR-/pAkt+/pPTEN- tumors (Mean OS=5.1±0.738years).

CONCLUSION

AR-expressing tumors are frequently characterized by low or intermediate grade tumors, expressing ER and PR. In addition, expression of AR, pAkt and pPTEN, could be considered in prognostication of patients with invasive BCa.

Mapping genetic alterations causing chemoresistance in cancer: identifying the roads by tracking the drivers

Although new agents are implemented to cancer therapy, we lack fundamental understandings of the mechanisms of chemoresistance, the main obstacle to cure in cancer. Here we review clinical evidence linking molecular defects to drug resistance across different tumour forms and discuss contemporary experimental evidence exploring these mechanisms. Although evidence, in general, is sparse and fragmentary, merging knowledge links drug resistance, and also sensitivity, to defects in functional pathways having a key role in cell growth arrest or death and DNA repair. As these pathways may act in concert, there is a need to explore multiple mechanisms in parallel. Taking advantage of massive parallel sequencing and other novel high-throughput technologies and base research on biological hypotheses, we now have the possibility to characterize functional defects related to these key pathways and to design a new generation of studies identifying the mechanisms controlling resistance to different treatment regimens in different tumour forms.

Occurrence and significance of epithelial-mesenchymal transition in breast cancer

By contrast with developmental epithelial-mesenchymal transition (EMT), where epithelial characteristics undergo transformation to a mesenchymal-like phenotype in a coordinated fashion, oncogenic EMT occurs in the context of unpredictable genetic changes present in the tumour cells, as well as an abnormal tumour microenvironment. Therefore, a partial form of EMT has been proposed as variably participating in the establishment of invasive phenotype in different types of breast carcinoma, in keeping with their morphological and phenotypical diversity. A complex network of signalling pathways and transcription factors appears responding to various growth factors and cytokines released by stromal and neoplastic elements, endowing the system with abundant regulatory opportunities. The process of EMT is largely elusive in histopathological preparations, prompting doubts regarding its significance in tumour progression. This might be related to the presumed focal occurrence of EMT in the majority of tumours. Detailed topological studies might facilitate understanding of the orchestration of events taking place in vivo. Even more importantly, clinical correlations can be endeavoured and, in parallel with advancement in molecular pathology, a contribution to taxonomy refinement can be envisaged.

Everolimus in the treatment of hormone receptor-positive breast cancer

INTRODUCTION

The phosphoinositide triphosphate kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) is a central regulatory pathway involved in cell proliferation, growth, differentiation, metabolism and survival. Deregulation of this pathway is well described in breast cancer and is associated to the development of endocrine resistance among hormone receptor (HR)-positive tumors. Everolimus , an mTOR-inhibitor has clinical activity against breast cancer and has shown to restore sensitivity to endocrine therapy.

AREAS COVERED

We review the clinical data and the results of the recently published clinical trials evaluating the use of everolimus in HR-positive breast cancer patients in combination with endocrine therapy. We discuss the data regarding efficacy but also describe in detail the side effect profile of this drug.

EXPERT OPINION

Everolimus represents a new therapeutic alternative for the treatment of HR-positive metastatic breast cancer. Everolimus is in general a well-tolerated drug, however, stomatitis, fatigue and hematological abnormalities are common. It is still unclear if there are specific subgroups of patients that receive greater benefit from everolimus and whether there is a relationship between the presence of PIK3CA mutations and efficacy. The results of biomarker studies will hopefully provide information that will help us determine which patients are most likely to benefit from this treatment.

Akt expression and compartmentalization in prediction of clinical outcome in HER2-positive metastatic breast cancer patients treated with trastuzumab

Trastuzumab is effective in about half of HER2-positive breast cancer patients. The PI3K/Akt signalling pathway plays an important role in the process of primary and secondary resistance to anti-HER2 targeted therapy. We evaluated the relationship between expression, activation and subcellular localization of selected Akt isoforms and response to trastuzumab-based anti-HER2 targeted therapy in patients with HER2-positive metastatic breast cancer. Seventy-four women with verified HER2-positive breast cancer were treated with trastuzumab for metastatic disease. Immunohistochemistry was used to evaluate Akt1, Akt2, pAkt Thr308 and pAkt Ser473 expression. For pAkt, cytoplasmic and nuclear fractions were assessed separately. Even though Akt isoforms were expressed in the majority of tumours, activated Akt (pAkt) was present in the cytoplasm only and not in the nucleus in >20% of tumours, and there was no pAkt at all in another 7–13% of tumours. Patients whose tumours showed strong Akt2 expression and had pAkt (pAkt-Thr308 and/or pAkt-Ser473) detectable in the cytoplasm as well as nucleus (n+c), exhibited improved time to progression (TTP) and overall survival from the initiation of trastuzumab therapy (OSt). Patients with tumours with strong Akt2 and pAkt Thr308 (n+c) had superior TTP (17.0 vs. 7.6 months, P=0.024; HR 0.52) and OSt (51.8 vs. 16.8 months, P=0.0009; HR 0.34) compared to other tumours. Similar results were found for strong Akt2 and pAkt Ser473 (n+c): TTP 13.1 vs. 7.2 months (P=0.085, HR 0.62) and OSt 50.8 vs. 17.0 months (P=0.009; HR 0.45). This study is the first to prove the significance of Akt kinase isoform, activity and compartmentalization for the prediction of response to trastuzumab-based therapy in patients with HER2-positive metastatic breast cancer.

Molecular logic underlying chromosomal translocations, random or non-random?

Chromosomal translocations serve as essential diagnostic markers and therapeutic targets for leukemia, lymphoma, and many types of solid tumors. Understanding the mechanisms of chromosomal translocation generation has remained a central biological question for decades. Rather than representing a random event, recent studies indicate that chromosomal translocation is a non-random event in a spatially regulated, site-specific, and signal-driven manner, reflecting actions involved in transcriptional activation, epigenetic regulation, three-dimensional nuclear architecture, and DNA damage-repair. In this review, we will focus on the progression toward understanding the molecular logic underlying chromosomal translocation events and implications of new strategies for preventing chromosomal translocations.

Diaminothiazoles inhibit angiogenesis efficiently by suppressing Akt phosphorylation

The prevention of neovessel formation or angiogenesis is a recent popular strategy for limiting and curing cancer. Diaminothiazoles are a class of compounds that have been reported to show promise in the treatment of cancer by inhibiting cancer cell proliferation and inducing apoptosis, because of their effects on microtubules and as inhibitors of cyclin-dependent kinases. Many microtubule-targeting agents are being studied for their antiangiogenic activity, and a few have shown promising activity in the treatment of cancer. Here, we report that diaminothiazoles can be highly effective as antiangiogenic agents, as observed in the chick membrane assay. The lead compound, 4-amino-5-benzoyl-2-(4-methoxyphenylamino)thiazole (DAT1), inhibits endothelial cell processes such as invasion, migration, and tubule formation, which require a functional cytoskeleton. DAT1 also decreases the expression of cell adhesion markers. The antiangiogenic activities of DAT1 occur at concentrations that are not cytotoxic to the normal endothelium. Analysis of intracellular signaling pathways shows that DAT1 inhibits Akt phosphorylation, which is actively involved in the angiogenic process. The antiangiogenic properties of diaminothiazoles, in addition to their promising antimitotic and cytotoxic properties in cancer cell lines, give them an extra advantage in the treatment of cancer.

Phospho-ERK and AKT status, but not KRAS mutation status, are associated with outcomes in rectal cancer treated with chemoradiotherapy

BACKGROUND

KRAS mutations may predict poor response to radiotherapy. Downstream events from KRAS, such as activation of BRAF, AKT and ERK, may also confer prognostic information but have not been tested in rectal cancer (RC). Our objective was to explore the relationships of KRAS and BRAF mutation status with p-AKT and p-ERK and outcomes in RC.

METHODS

Pre-radiotherapy RC tumor biopsies were evaluated. KRAS and BRAF mutations were assessed by pyrosequencing; p-AKT and p-ERK expression by immunohistochemistry.

RESULTS

Of 70 patients, mean age was 58; 36% stage II, 56% stage III, and 9% stage IV. Responses to neoadjuvant chemoradiotherapy: 64% limited, 19% major, and 17% pathologic complete response. 64% were KRAS WT, 95% were BRAF WT. High p-ERK levels were associated with improved OS but not for p-AKT. High levels of p-AKT and p-ERK expression were associated with better responses. KRAS WT correlated with lower p-AKT expression but not p-ERK expression. No differences in OS, residual disease, or tumor downstaging were detected by KRAS status.

CONCLUSIONS

KRAS mutation was not associated with lesser response to chemoradiotherapy or worse OS. High p-ERK expression was associated with better OS and response. Higher p-AKT expression was correlated with better response but not OS.

Overview of the generation, validation, and application of phosphosite-specific antibodies

Protein phosphorylation is a universal key posttranslational modification that affects the activity and other properties of intracellular proteins. Phosphosite-specific antibodies can be produced as polyclonals or monoclonals in different animal species, and each approach offers its own benefits and disadvantages. The validation of phosphosite-specific antibodies requires multiple techniques and tactics to demonstrate their specificity. These antibodies can be used in arrays, flow cytometry, and imaging platforms. The specificity of phosphosite-specific antibodies is key for their use in proteomics and profiling of disease.

COX-2 activation is associated with Akt phosphorylation and poor survival in ER-negative, HER2-positive breast cancer

Background

Inducible cyclooxgenase-2 (COX-2) is commonly overexpressed in breast tumors and is a target for cancer therapy. Here, we studied the association of COX-2 with breast cancer survival and how this association is influenced by tumor estrogen and HER2 receptor status and Akt pathway activation.

Methods

Tumor COX-2, HER2 and estrogen receptor α (ER) expression and phosphorylation of Akt, BAD, and caspase-9 were analyzed immunohistochemically in 248 cases of breast cancer. Spearman's correlation and multivariable logistic regression analyses were used to examine the relationship between COX-2 and tumor characteristics. Kaplan-Meier survival and multivariable Cox proportional hazards regression analyses were used to examine the relationship between COX-2 and disease-specific survival.

Results

COX-2 was significantly associated with breast cancer outcome in ER-negative [Hazard ratio (HR) = 2.72; 95% confidence interval (CI), 1.36-5.41; comparing high versus low COX-2] and HER2 overexpressing breast cancer (HR = 2.84; 95% CI, 1.07-7.52). However, the hazard of poor survival associated with increased COX-2 was highest among patients who were both ER-negative and HER2-positive (HR = 5.95; 95% CI, 1.01-34.9). Notably, COX-2 expression in the ER-negative and HER2-positive tumors correlated significantly with increased phosphorylation of Akt and of the two Akt targets, BAD at Ser136 and caspase-9 at Ser196.

Conclusions

Up-regulation of COX-2 in ER-negative and HER2-positive breast tumors is associated with Akt pathway activation and is a marker of poor outcome. The findings suggest that COX-2-specific inhibitors and inhibitors of the Akt pathway may act synergistically as anticancer drugs in the ER-negative and HER2-positive breast cancer subtype.

Clinical and biological significance of GSK-3β inactivation in breast cancer-an immunohistochemical study

Glycogen synthase kinase 3β, recently found to be functionally abnormal in various types of human disease, is negatively regulated by the PI3K/Akt signaling pathway. As Akt is constitutively activated in a subset of breast cancer, we hypothesized that glycogen synthase kinase 3β is inappropriately inactivated in these cases. In this study, we aimed to assess (1) the overall frequency of glycogen synthase kinase 3β inactivation in breast cancer; (2) whether there is an association between Akt activation and glycogen synthase kinase 3β inactivation; and (3) whether there is a correlation between glycogen synthase kinase 3β inactivation and various pathologic and clinical parameters. The phosphorylated form of glycogen synthase kinase 3β (pGSK-3β) and Akt (pAkt) were used as surrogate markers for glycogen synthase kinase 3β inactivation and Akt activation, respectively. Immunohistochemistry applied to paraffin-embedded tissues was used to assess 72 consecutive invasive mammary carcinomas, of which 50 were estrogen receptor positive. Overall, pGSK-3β and pAkt were positive in 34 (47.2%) and 35 (48.6%) cases, respectively. These 2 markers were significantly correlated with each other in the overall group and in the estrogen receptor-positive subgroup (P = .01 and .003, Spearman, respectively). Importantly, pGSK-3β, but not pAkt, significantly correlated a worse clinical outcome in this cohort (P = .004, log rank). In summary, evidence of glycogen synthase kinase 3β inactivation was found in approximately half of the invasive mammary carcinomas. Our data suggest that this abnormality is likely attributed to Akt activation and that glycogen synthase kinase 3β inactivation confers a worse clinical outcome.

Increased activated Akt expression in renal cell carcinomas and prognosis

Renal carcinogenesis is promoted by overexpression of the activated serine/ threonine kinase Akt (p-Akt) and supposedly a concomitant reduction in phosphatase and tensin homologue deleted on chromosome 10 tumour suppressor gene (PTEN), which normally inhibits the activation of Akt. Because promising anti-cancer therapies increasingly focus on pathways involving p-Akt and PTEN, the present study evaluated the expression of p-Akt in renal cell carcinomas and compared it with prognosis. P-Akt and PTEN expression were analysed in a tissue microarray (TMA) from renal cell carcinoma (n = 386) and adjacent uninvolved renal tissue (n = 32) specimens. Increased p-Akt was found more often in the nucleus than in the cytoplasm, and PTEN was concomitantly reduced in about 50% of cases. Neither tumour grade nor stage influenced p-Akt expression, whereas the clear cell and papillary subtypes showed increased p-Akt more often than did the chromophobe or sarcomatoid types. Increased cytoplasmic and nuclear p-Akt levels were independent prognostic factors for diminishing patient survival. The present study found significantly increased nuclear but also cytoplasmic p-Akt expression in renal cell carcinoma subtypes. Increased nuclear and cytoplasmic p-Akt was an independent prognostic factor for diminishing patient survival. The considerable number of high-grade and high-stage RCC showing increased p-Akt and reduced PTEN would justify further evaluation of therapeutic concepts based on inhibitors of the PI3K/p-Akt/mTOR pathway.

FOXO1A is a target for HER2-overexpressing breast tumors

Trastuzumab treatment has improved the overall survival of HER2-overexpressing breast cancer patients. However, many of these patients will eventually become resistant to treatment. The mechanisms that contribute to resistance to trastuzumab are unknown. In this study, we tested the hypothesis that targeting of the FKHR transcription factor FOXO1A in HER2-overexpressing breast tumor cells can overcome the trastuzumab resistance in vitro. We have shown that overexpression of HER2 leads to activation of phosphatidylinositol 3-kinase (PI3K)/Akt pathway and subsequent inactivation of FOXO1A in HER2-overexpressing breast cancer cells SKBR3, BT474, and MCF7-HER2. In wild-type SKBR3 and BT474 cells, trastuzumab downregulates active Akt and increases FOXO1A expression that leads to increase in p27(kip1) and decrease in cyclin D1 and finally inhibits cell proliferation. In contrast, the effect of trastuzumab was eliminated by the reduction of FOXO1A in HER2-overexpressing cells with constitutively active Akt1 (SKBR3/AA28 and BT474/AA9). The downregulation of FOXO1A resulted in nuclear export of p27(kip1). Blocking the constitutively active Akt by a specific Akt/protein kinase B signaling inhibitor-2 (API-2) significantly increased FOXO1A expression and rendered the cells more responsive to trastuzumab-induced growth inhibition. Reactivation of FOXO1A by stable or transient transfection also restored the growth-inhibitory effects of trastuzumab in SKBR3/AA28, BT474/AA9, and MCF7-HER2 cells. Knocking down FOXO1A by small interfering RNA resulted in reducing trastuzumab-induced growth inhibition. In summary, trastuzumab can inhibit proliferation of HER2-overexpressing breast cancer cells by reactivating FOXO1A through inhibition of the PI3K/Akt pathway. FOXO1A may therefore serve as a target for HER2-overexpressing breast tumors.

Pdcd4 repression of lysyl oxidase inhibits hypoxia-induced breast cancer cell invasion

Metastasis to bone, liver and lungs is the primary cause of death in breast cancer patients. Our studies have revealed that the novel tumor suppressor Pdcd4 inhibits breast cancer cell migration and invasion in vitro. Loss of Pdcd4 in human nonmetastatic breast cancer cells increased the expression of lysyl oxidase (LOX) mRNA. LOX is a hypoxia-inducible amine oxidase, the activity of which enhances breast cancer cell invasion in vitro and in vivo. Specific inhibition of LOX activity by beta-aminopropionitrile or small interfering RNA decreased the invasiveness of T47D and MCF7 breast cancer cells attenuated for Pdcd4 function. Most significantly, loss of Pdcd4 augments hypoxia induction of LOX as well. Conversely, overexpression of Pdcd4 significantly reversed the hypoxia induction of LOX expression in T47D cells attenuated for Pdcd4. However, Pdcd4 did not affect hypoxia-inducible factor-1 (HIF-1) protein expression or HIF-1-responsive element-luciferase activity in response to hypoxia, suggesting that Pdcd4 regulation of LOX occurs through an HIF-independent mechanism. Nevertheless, the loss of Pdcd4 early in cancer progression may have an important role in the increased sensitivity of cancer cells to hypoxia through increased LOX activity and concomitant enhanced invasiveness.

Higher pAkt expression predicts a significant worse prognosis in glioblastomas

phosphorylated-Akt (pAkt) plays an important role in tumorigenesis through promotion of cell survival by inhibiting apoptosis and mediating cell proliferation. Higher expression of pAkt has been reported to be associated with an unfavorable prognosis in several malignant tumors. In this study, the prognostic value of pAkt expression was investigated in glioblastomas by using immunohistochemical methods. Tissue sections obtained from 64 patients with glioblastoma were evaluated. The mean and median follow-up period was 16.2 +/- 12.4 and 12 months, respectively (range: from 1 to 62 months). pAkt expression levels were determined by immunohistochemical staining and evaluated for cell positivity. Positive staining was defined when more than 50% of the tumor cells were stained in each section. The correlation between expression of pAkt and overall survival rate was assessed. Glioblastomas showed either or both cytoplasmic and nuclear positive findings for pAkt. A total of 29.7% (19/64) of tissue specimens had greater than 50% positivity. The median survival periods of the patients with pAkt positive and negative tumor were 10 and 14 months, respectively. Two years overall survival rate of the pAkt positive and negative patients were 0% and 24.4%, respectively. Survival rate of the patients with pAkt positive tumor was significantly lower than that of the patients with pAkt negative tumors (p = 0.004). Multivariate analysis showed that extent of surgery was the strongest factor for survival (p = 0.01) and the pAkt expression was the secondly strongest factor (p = 0.06). These results suggest that the higher expression of pAkt the poorer prognosis in patients with glioblastoma.

Potential prognostic value of heat-shock protein 90 in the presence of phosphatidylinositol-3-kinase overexpression or loss of PTEN, in invasive breast cancers

Introduction

Evaluating the expression of signaling molecule proteins from the mitogen-activated protein kinase (MAPK) pathway and the phosphatidylinositol-3-kinase (PI3K) pathway in invasive breast cancers may identify prognostic marker(s) associated with early relapse.

Methods

Immunohistochemical analyses of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), PI3K-p110α, phospho-AKT, phospho-p70S6 kinase, phospho-S6 ribosomal protein, phospho-RAF, phospho-p44/42 MAPK, and heat-shock protein 90 (HSP90) were performed on tumor samples from 212 patients with invasive breast cancer. Statistically significant relations between protein expression, clinicopathologic factors, and relapse-free survival (RFS) were analyzed.

Results

Expression of HSP90 was associated with 5-year RFS, as well as T stage, N stage, histologic grade, estrogen receptor (ER) expression, human epidermal growth factor receptor 2 (HER2) expression, and the Ki-67 proliferation index. On multivariate analysis, coexpression of HSP90 and PI3K-p110α or expression of HSP90 along with PTEN loss demonstrated significantly worse RFS. In subgroup analyses, both exhibited strong prognostic significance in HER2-positive cases, but not in HER2-negative cases.

Conclusions

The coexpression of HSP90 with PI3K-p110α or expression of HSP90 along with PTEN loss has a potential as a molecular prognostic marker to predict early relapse in patients with invasive breast cancers.

Clinical significance of pAKT and CD44v6 overexpression with breast cancer

PURPOSE

CD44v6 contributes to apoptosis resistance and metastasis via upregulated activity of the PI3K/AKT pathway. The purpose of this study was to investigate the expression patterns and predictive value of phosphorylated AKT (pAKT) and CD44v6 in breast cancer tissues.

METHODS

Expression of pAkt and CD44v6 protein was detected using immunohistochemistry in breast cancer tissues and lymph node tissues in 98 patients. The correlation between the expression of pAkt, CD44v6 and other disease-related characteristics was investigated. The prognostic value of pAKT and CD44v6 overexpression for overall survival (OS) and disease free survival (DFS) was determined.

RESULTS

37 cases (37.8%) were observed as positive for pAkt expression, and 38 cases (38.8%) for CD44V6 overexpression. Staining was positive for pAKT in 20 of 38 (52.6%) CD44v6(+) and 17 of 60 (28.3%) CD44v6(-) (P = 0.016). A progressively increased trend of CD44v6 overexpression was observed from node(-) primary breast cancer tissues to node(+) primary cancer tissues to node(+) lymph tissues (P = 0.000). In univariate analysis lymph node status, pAKT and CD44V6 were significantly associated with a decreased OS and DFS. Multivariate analysis revealed that CD44v6 status was associated with a reduced OS (P = 0.003), and pAKT and CD44v6 with a shorter DFS (P = 0.012 and 0.016, respectively).

CONCLUSIONS

Our data suggested that there had an intensive relationship between pAKT and CD44v6 expression in breast cancer tissues. The overexpression of CD44v6 was an independent prognostic marker for predicting OS and DFS of breast cancer patients.

Advances in research on the mechanisms of tamoxifen therapy for cholangiocarcinoma

Cholangiocarcinoma (CCA) is a kind of malignancy arising from the epithelial cells lining the intrahepatic and extrahepatic bile ducts. Because of the difficulty in early diagnosis and poor therapeutic effect, the five-year survival rate for CCA patients is low. Therefore, there is an urgent need to develop new effective chemotherapy drugs for CCA. Tamoxifen (TAM), as a nonsteroidal antiestrogen mainly used for therapy of breast cancer, also exhibits antitumor activity against other tumors, including CCA. However, the exact mechanisms of tamoxifen therapy for CCA have not been completely elucidated yet. This paper reviews the recent advances in research on the mechanisms of TAM therapy for CCA.

Immunohistochemical detection of phospho-Akt, phospho-BAD, HER2 and oestrogen receptors alpha and beta in Malaysian breast cancer patients

Activation of Akt signaling pathway has been documented in various human malignancies, including breast carcinoma. The objective of this study is to determine the incidence of Akt phosphorylation in breast tumours and its relationship with expression of ER-alpha, ER-beta, HER2, Ki-67 and phosphorylated Bcl-2 associated death domain (p-BAD). Immunohistochemical staining was performed to detect these molecules on 43 paraffin-embedded breast tumour tissues with commercially available antibodies. Eighteen (41.9%), 3 (7.0%), 23 (53.5%), 35 (81.4%), 21 (48.8%), 29 (67.4%), and 34 (81.0%) of breast tumours were positive for nuclear ER-alpha, nuclear ER-beta, membranous HER2, cytonuclear p-Akt (Thr308), p-Akt (Ser473), p-BAD and Ki-67, respectively. ER-alpha expression was inversely correlated with HER2 and Ki-67 (P = 0.041 and P = 0.040, respectively). The p-Akt (Ser473) was correlated with increased level of p-BAD (Ser136) (P = 0.012). No relationship of Akt phosphorylation with HER2, ER-alpha or ER-beta was found. The p-Akt (Ser473) immunoreactivity was significantly higher in stage IV than in stage I or II (P = 0.036 or P = 0.009). The higher Ki-67 and lower ER-alpha expression showed an association with patient age of <50 years (P = 0.004) and with positive nodal status (P = 0.033), respectively. Our data suggest that the Akt phosphorylation and inactivation of its downstream target, BAD may play a role in survival of breast cancer cell. This study does not support the simple model of linear HER2/PI3K/Akt pathway in breast cancer.

AKT1 pleckstrin homology domain E17K activating mutation in endometrial carcinoma

OBJECTIVES

The PI3K/AKT pathway is frequently activated in endometrial carcinoma (EC) mainly due to mutations in the PIK3CA and PTEN genes. These events are common and believed to be the key to endometrial carcinogenesis. Recently, a somatic activating mutation in the AKT1 gene (E17K) was identified in several cancer types. In this study we explored the frequency of this AKT1 mutation in endometrial carcinoma.

METHODS

Tumor DNA, extracted from 73 EC was analyzed for AKT1 E17K mutation (G49A) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In addition, the tumors were screened for coexisting common mutations in PTEN, PIK3CA and KRAS.

RESULTS

The AKT1 E17K mutation was detected in 4% of EC. One of the AKT1-mutated tumors showed coexisting PTEN loss-of-function mutation.

CONCLUSION

We identified the AKT1 E17K mutation in 4% of endometrial carcinomas. The presence of double AKT1/ PTEN mutants is in accord with the hypothesis that in EC more than one hit is required to completely activate the PI3K pathway. Furthermore, AKT1 mutations were limited to high grade, advanced stage tumors suggesting that this mutation confers a more aggressive tumor behavior.

Overexpression of Akt/PKB modulates N-myristoyltransferase activity in cancer cells

N-myristoyltransferase (NMT) catalyses the myristoylation reaction. Since NMT activity is elevated in various cancers and activated Akt/PKB leads to cell survival, we were interested in studying if activation of Akt/PKB has any effect on NMT. Overexpression of constitutively active Akt/PKB in HepG2 cells (HepG2-CA-Akt/PKB) led to an approximately 50% reduction of NMT compared with parental HepG2 cells. Reduced NMT activity in HepG2-CA-Akt/PKB was found to be due to the NMT1 phosphorylation. We determined NMT activity in various human breast cancer cell lines with differing metastatic potentials and pseudo-normal breast cells (HBL-100). Tumourigenic or metastatic breast cancer cell lines such as MDA-MB-231, MDA-MB-435, and Hs 578T displayed reduced NMT activity. Western blot analysis revealed that NMT1 is phosphorylated in these breast cancer cells. Furthermore, patients' breast cancer tissue array revealed strong positivity and high intensity for NMT in malignant breast tissues compared with normal breast cells. A gradation in the NMT staining was observed for grade I, II, and III infiltrating ductal carcinoma breast tissues. These studies demonstrate that overexpression of Akt/PKB results in NMT1 phosphorylation and that NMT1 is phosphorylated in breast cancer cells. Immunohistochemical analysis suggests that NMT may prove to be an added diagnostic biomarker for breast cancer.

Automated quantitative assessment of HER-2/neu immunohistochemical expression in breast cancer

The expression of the HER-2/neu (HER2) gene, a member of the epidermal growth factor receptor family, has been shown to be a valuable prognostic indicator for breast cancer. However, interobserver variability has been reported in the evaluation of HER2 with immunohistochemistry. It has been suggested that automated computer-based evaluation can provide a consistent and objective evaluation of HER2 expression. In this manuscript, we present an automated method for the quantitative assessment of HER2 using digital microscopy. The method processes microscopy images from tissue slides with a multistage algorithm, including steps of color pixel classification, nuclei segmentation, and cell membrane modeling, and extracts quantitative, continuous measures of cell membrane staining intensity and completeness. A minimum cluster distance classifier merges the features to classify the slides into HER2 categories. An evaluation based on agreement analysis with pathologist-derived HER2 scores, showed good agreement with the provided truth. Agreement varied within the different classes with highest agreement (up to 90%) for positive (3+) slides, and lowest agreement (72%-78%) for equivocal (2+) slides which contained ambiguous scoring. The developed automated method has the potential to be used as a computer aid for the immunohistochemical evaluation of HER2 expression with the objective of increasing observer reproducibility.

Dysregulated PI3K/Akt/PTEN pathway is a marker of a short disease-free survival in node-negative breast carcinoma

The phosphoinositide 3-kinase/Akt pathway is involved in the pathogenesis of several human cancers. In this study, the biological and prognostic value of phosphoinositide 3-kinase/Akt pathway dysregulation was assessed by immunohistochemistry in a well-characterized series of 72 patients with node-negative breast cancer with a long-term follow-up. Phosphorylated Akt and PTEN expression was reduced in 32% and 12.5% of the tumors, respectively. Phosphorylated Akt or PTEN status was not associated with the main clinicopathologic and biological parameters, whereas their expression was tightly related to their downstream targets cyclin D1 and p27(Kip1) which are involved in cell proliferation. Survival analysis showed a strong association between a shorter disease-free survival and the dysregulated expression of phosphorylated Akt (P = .036), PTEN (P = .003), p27(Kip1) (P = .008), and Ki67 (P = .0007), or the distinct subtypes of breast tumors (luminal, HER2 overexpressing, and basal-like; P = .03). Moreover, multivariate analysis using the Cox proportional-hazards regression model showed that PTEN and Ki67 were independent predictive factors of disease recurrence and that their simultaneous dysregulation strongly increased the hazards ratio of the patients with node-negative breast cancer (hazards ratio, 38.30; P = .0014). In conclusion, our results show that the dysregulation of the phosphoinositide 3-kinase/Akt/PTEN pathway is relevant to the prognosis in node-negative breast carcinoma and that the evaluation of key components of this pathway might be a useful tool to identify the patients with node-negative breast cancer at high-risk of disease recurrence.

Molecular mechanisms of tamoxifen therapy for cholangiocarcinoma: role of calmodulin

PURPOSE

Cholangiocarcinoma is a fatal tumor with limited therapeutic options. We have reported that calmodulin antagonists tamoxifen and trifluoperazine induced apoptosis in cholangiocarcinoma cells. Here, we determined the effects of tamoxifen on tumorigenesis and the molecular mechanisms of tamoxifen-induced apoptosis.

EXPERIMENTAL DESIGN

Nude mice xenograft model of cholangiocarcinoma was used and tamoxifen was given i.p. and intratumorally. Cholangiocarcinoma cells were used to characterize molecular mechanisms of tamoxifen-induced apoptosis in vitro.

RESULTS

I.p. or intratumoral injection of tamoxifen decreased cholangiocarcinoma tumorigenesis by 40% to 80% in nude mice. In cells isolated from tumor xenografts, tamoxifen inhibited phosphorylation of AKT (pAKT) and cellular FLICE like inhibitory protein (c-FLIP). Immunohistochemical analysis further showed that pAKT was identified in all nontreated tumors but was absent in tamoxifen-treated tumors. In vitro, tamoxifen activated caspase-8 and caspase-10, and their respective inhibitors partially blocked tamoxifen-induced apoptosis. Overexpression of c-FLIP inhibited tamoxifen-induced apoptosis and enhanced tumorigenesis of cholangiocarcinoma cells in nude mice, whereas deletion of the calmodulin-binding domain on c-FLIP restored the sensitivity to tamoxifen and inhibited tumorigenesis. With two additional cholangiocarcinoma cell lines, we confirmed that the expression of FLIP is an important factor in mediating spontaneous and tamoxifen-induced apoptosis.

CONCLUSIONS

Thus, tamoxifen inhibits cholangiocarcinoma tumorigenesis in nude mice. Tamoxifen-induced apoptosis is partially dependent on caspases, inhibition of pAKT, and FLIP expression. Further, calmodulin-FLIP binding seems to be important in FLIP-mediated resistance to tamoxifen. Therefore, the present studies support the concept that tamoxifen may be used as a therapy for cholangiocarcinoma and possibly other malignancies in which the calmodulin targets AKT and c-FLIP play important roles in the tumor pathogenesis.

Identification of a potent herbal molecule for the treatment of breast cancer

BACKGROUND

Breast cancer (BCa)-related mortality still remains the second leading cause of cancer-related deaths worldwide. Patients with BCa have increasingly shown resistance and high toxicity to current chemotherapeutic drugs for which identification of novel targeted therapies are required.

METHODS

To determine the effect of PDBD on BCa cells, estrogen-receptor positive (ER+)-MCF-7 and estrogen-receptor negative (ER-)-MDA 231 cells were treated with PDBD and the cell viability, apoptotic, cell cycle, Western blot and Promoter assays were performed.

RESULTS

PDBD inhibits cell viability of ER+ and ER- BCa cells by inducing apoptosis without causing significant toxicity in normal breast epithelial cells. While dissecting the mechanism of action of PDBD on BCa, we found that PDBD inhibits Akt signaling and its downstream targets such as NF-kappaB activation, IAP proteins and Bcl-2 expression. On the other hand, activation of JNK/p38 MAPK-mediated pro-apoptotic signaling was observed in both ER+ and ER- BCa cells.

CONCLUSION

These findings suggest that PDBD may have wide therapeutic application in the treatment of BCa.

Activated Akt as an indicator of prognosis in gastric cancer

The immunohistochemical expression of phosphorylated (activated) Akt (pAkt) in 50 advanced gastric carcinomas has been analyzed and the results correlated with age, sex, location in the stomach, histotype, stage, survival, mitotic and apoptotic index, some cell cycle regulators (cyclin D1, cyclin E, p34/cdc2, p27/kip1), and cell proliferation. There was a statistically significant direct correlation between pAkt expression (both cytoplasmatic and nuclear) and depth of infiltration of the tumor, number of infiltrated lymph nodes and p34/cdc2 expression, and between prevalently nuclear pAkt and cyclin D1 and cyclin E. Conversely, there was a significant inverse correlation between nuclear pAkt and apoptotic index and between cytoplasmatic and nuclear pAkt and patient survival. No correlation was found between pAkt and sex, age, tumor location, histotype, mitotic index, and cell proliferation. These findings suggest that pAkt may be considered an indicator of tumor progression and patient survival in gastric cancer.

Immunohistochemical assessment of protein phosphorylation state: the dream and the reality

The development of phosphorylation state-specific antibodies (PSSAs) in the 1980s, and their subsequent proliferation promised to enable in situ analysis of the activation states of complex intracellular signaling networks. The extent to which this promise has been fulfilled is the topic of this review. I review some applications of PSSAs primarily in the assessment of solid tumor signaling pathway activation status. PSSAs have received considerable attention for their potential to reveal cell type-specific activation status, provide added prognostic information, aid in the prediction of response to therapy, and most recently, demonstrate the efficacy of kinase-targeted chemotherapies. However, despite some successes, many studies have failed to demonstrate added value of PSSAs over general antibody immunohistochemistry. Moreover, there is still a large degree of uncertainty about the interpretation of complex and heterogeneous staining patterns in tissue samples and their relationship to the actual phosphorylation states in vivo. The next phase of translational research in applications of PSSAs will entail the hard work of antibody validation, gathering of detailed information about epitope-specific lability, and implementation of methods for standardization.

VEGF stimulation of mitochondrial biogenesis: requirement of AKT3 kinase

The growth factor, vascular endothelial growth factor (VEGF), induces angiogenesis and promotes endothelial cell (EC) proliferation. Affymetrix gene array analyses show that VEGF stimulates the expression of a cluster of nuclear-encoded mitochondrial genes, suggesting a role for VEGF in the regulation of mitochondrial biogenesis. We show that the serine threonine kinase Akt3 specifically links VEGF to mitochondrial biogenesis. A direct comparison of Akt1 vs. Akt3 gene silencing was performed in ECs and has uncovered a discrete role for Akt3 in the control of mitochondrial biogenesis. Silencing of Akt3, but not Akt1, results in a decrease in mitochondrial gene expression and mtDNA content. Nuclear-encoded mitochondrial gene transcripts are also found to decrease when Akt3 expression is silenced. Concurrent with these changes in mitochondrial gene expression, lower O(2) consumption was observed. VEGF stimulation of the major mitochondrial import protein TOM70 is also blocked by Akt3 inhibition. In support of a role for Akt3 in the regulation of mitochondrial biogenesis, Akt3 silencing results in the cytoplasmic accumulation of the master regulator of mitochondrial biogenesis, PGC-1alpha, and a reduction in known PGC-1alpha target genes. Finally, a subtle but significant, abnormal mitochondrial phenotype is observed in the brain tissue of AKT3 knockout mice. These results suggest that Akt3 is important in coordinating mitochondrial biogenesis with growth factor-induced increases in cellular energy demands.

Expression patterns and predictive value of phosphorylated AKT in early-stage breast cancer

BACKGROUND

AKT phosphorylation is a critical step in the activation of growth factor receptors and can mediate tumor resistance to anthracyclines. We evaluated the expression patterns and predictive value of phosphorylated AKT (pAKT) in breast cancer tissues.

PATIENTS AND METHODS

pAKT expression was assessed by immunohistochemistry in 823 tumors from patients with early breast cancer enrolled in two randomized trials. The distribution of pAKT expression was correlated with HER2 and epidermal growth factor receptor (EGFR) expression. The predictive value of pAKT for the efficacy of adjuvant chemotherapy was determined by test for interaction.

RESULTS

pAKT, EGFR, and HER2 were expressed in 119 of 781 (15%), 118 of 758 (16%), and 99 of 775 (13%) assessable tumors. Staining was positive for pAKT in 28 of 99 (28%) and 90 of 676 (13%) HER2+ and HER2- tumors (P < 0.001). pAKT was expressed in 15 of 94 (16%) and 75 of 563 (13%) HER2-/EGFR+ and HER2-/EGFR- tumors, respectively (P = 0.49). A positive staining for pAKT did not correlate with prognosis (P = 0.94), and did not predict the resistance to anthracyclines (test for interaction, P = 0.70).

CONCLUSIONS

AKT phosphorylation is associated with HER2 expression but not EGFR expression in patients with early breast cancer. pAKT is not predictive for the efficacy of anthracycline-based adjuvant chemotherapy.

Clinical significance of Akt and HER2/neu overexpression in African-American and Latina women with breast cancer

Introduction

Breast cancer patients with HER2/neu overexpression have poor outcomes with a decrease in disease-free survival (DFS) and overall survival. The biology of HER2/neu overexpression in breast tumors in African-American and Latina women is poorly understood. The purpose of this study is to understand the clinical significance of activated Akt (phospho-Akt or pAkt) expression in breast tumors from African-American and Latina patients with corresponding tissue HER2/neu overexpression. Cellular and molecular studies have shown that activation of the cell signaling phosphatidylinositol-3-kinase/Akt cascade via the HER2/neu and other receptor tyrosine kinases induces cell proliferation.

Methods

A total of 234 African-American and Latina patients were selected retrospectively. From this group, 141 tumor tissue samples were analyzed for tissue pAkt by immunohistochemistry (IHC). This cohort consisted of 46 HER2/neu-positive (3+ by IHC) and 95 HER2/neu-negative tumors. The prognostic value of activated tissue Akt in relation to HER2/neu overexpression for DFS was determined.

Results

Patients with low pAkt and HER2-negative tumors had the best DFS. As expected, HER2/neu-overexpressing tumors with low pAkt had a decrease in DFS. Similarly, those with high pAkt and HER2-negative tumors also had poor DFS. However, those with an increase in both HER2 and pAkt had the worst DFS. An increase in pAkt was significantly associated with HER2/neu-positive and lymph node-positive breast tumors. Tumors with high HER2 and high pAkt were metastatic. Multivariate analysis demonstrated that, in addition to the common risk factors such as larger tumor size, lymph node involvement, estrogen receptor/progesterone receptor-negative tumors, and HER2/neu-positive tumors, overexpression of pAkt significantly was associated with a decrease in 5-year DFS. A decrease in DFS with an increase in pAkt was observed in both HER2/neu-positive and -negative groups. However, the DFS was similar between HER2/neu-positive/pAkt-negative and HER2/neu-negative/pAkt-positive groups.

Conclusion

Our data suggest that there may be differences in tumor phenotypes within the HER2/neu-overexpressing breast cancer patients. The overexpression of pAkt may be a powerful prognostic marker for predicting DFS and overall survival of breast cancer patients.

Activation of the ERK and AKT signalling pathway predicts poor prognosis in hepatocellular carcinoma and ERK activation in cancer tissue is associated with hepatitis C virus infection

BACKGROUND/AIMS

The aim of the study was to determine the prognostic relevance of AKT and extracellular regulated kinases (ERK1/2), which are implied in the regulation of cell proliferation and apoptosis, in hepatocellular carcinoma (HCC).

METHODS

This study comprised a series of 208 patients incorporating HCCs treated either by surgical resection (n = 109) or liver transplantation (n = 99). Immunohistochemically demonstrated phospho-ERK1/2 (pERK1/2) and phospho-AKT (pAKT) was correlated with a series of clinico-pathologically relevant parameters (EGFR, Cyclin-D1, HCV/HBV infection, liver cirrhosis, chronic alcohol abuse), proliferative activity, and apoptosis.

RESULTS

Activation of ERK1/2 correlated statistically with the presence of HCV infection. pERK1/2 (P < 0.001) and pAKT (P = 0.052) expression showed a significant correlation with a decreased overall survival (OS). In multivariate Cox regression analysis pERK1/2 was identified as an independent prognostic parameter in HCC (P = 0.026).

CONCLUSIONS

Activation of ERK1/2 in HCC cancer indicates aggressive tumour behaviour and constitutes an independent prognostic factor. Furthermore our data confirm that HCV infection activates the ERK pathway and thereby might contribute to HCC carcinogenesis. Immunohistochemical determination of pERK1/2 status can thus be proposed as a promising candidate for the identification of high risk patients who may benefit from new anticancer drugs targeting the ERK-pathway.

AKT and ERK1/2 signaling in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinomas (ICC) are neoplasms that originate from cholangiocytes and can occur at any level of the biliary tree. Surgical resection is the current therapy of choice for this highly aggressive cancer. However, the 5-year survival still is poor, with high recurrence rates. Due to the intrahepatic growth a significant proportion of patients present with advanced disease and are not candidates for curative surgery or transplantation. The existing palliative options are of limited benefit and there is a great necessity for novel therapeutic options. In this article we review the role of the phosphoinositide 3-kinase(PI3K)/AKT and extracellular regulated kinase (ERK) signaling pathways in ICC and present new data on the prognostic value of these protein kinases. Finally, we discuss future upcoming therapeutic options based on targeting these signaling pathways.

Akt-induced endocrine therapy resistance is reversed by inhibition of mTOR signaling

BACKGROUND

Resistance to endocrine therapy is a major impediment in breast cancer therapeutics. The Phosphatidylinositol-3-OH kinase (PI3K)/Protein kinase B (Akt/PKB) kinase signaling pathway has been implicated in altering breast cancer response to multiple therapies. How Akt modulates response is an area of significant clinical relevance.

METHODS

We have used an in vitro model to discern the effects of robust Akt activity on breast cancer cellular response to endocrine therapies.

RESULTS

High levels of Akt activity confer resistance to the aromatase inhibitor Letrozole (Let) and the selective estrogen receptor (ER) down-regulator Fulvestrant (ICI). Akt-induced resistance is not due to failure of these endocrine agents to inhibit estrogen receptor alpha activity. Instead, resistance is characterized by altered cell cycle and apoptotic response. Cotreatment with low concentrations of the mTOR inhibitor RAD-001 and either Let or ICI restores response of the resistant cells to levels observed in the responsive cells treated with either Let or ICI as a single agent.

CONCLUSIONS

Our preliminary findings in experiments with RAD-001 indicate that cotreatment with mTOR inhibitors and either Let or ICI reverses the Akt-mediated resistance and restores responsiveness to antiestrogens. Concurrent ER and mTOR inhibition is therefore an effective strategy to overcome growth factor-induced resistance and bears significant implications for optimal clinical development of these agents in breast cancer treatment.