Correlations of cell cycle regulators (p53, p21, pRb and mdm2) and c-erbB-2 with biological markers of proliferation and overall survival in breast cancer

PD-L1 intrinsically promotes the proliferation of breast cancer cells through the SKP2-p27/p21 axis

BACKGROUND

PD-L1 intrinsically promotes tumor progression through multiple mechanisms, which potentially leads to resistance to anti-PD-1/PD-L1 therapies. The intrinsic effect of PD-L1 on breast cancer (BC) cell proliferation has not been fully elucidated.

METHODS

we used proteomics, gene expression knockdown (KD), quantitative immunofluorescence (qIF), western blots, functional assays including colony-forming assay (CFA) and real-time cell analyzer (RTCA), and in vivo data using immunohistochemistry in breast cancer patients.

RESULTS

PD-L1 promoted BC cell proliferation by accelerating cell cycle entry at the G1-to-S phase transition. Global proteomic analysis of the differentially expressed nuclear proteins indicated the involvement of several proliferation-related molecules, including p21CIP1/WAF1. Western blotting and qIF demonstrated the higher expression of SKP2 and the lower expression of p21CIP1/WAF1 and p27Kip1 in PD-L1 expressing (PD-L1pos) cells as compared to PD-L1 KD (PD-L1KD) cells. Xenograft-derived cells and the TCGA BC dataset confirmed this relationship in vivo. Functionally, CFA and RTCA demonstrated the central role of SKP2 in promoting PD-L1-mediated proliferation. Finally, immunohistochemistry in 74 breast cancer patients confirmed PD-L1 and SKP-p21/p27 axis relationship, as it showed a highly statistically significant correlation between SKP2 and PD-L1 expression (p < 0.001), and both correlated significantly with the proliferation marker Ki-67 (p < 0.001). On the other hand, there was a statistically significant inverse relationship between PD-L1 and p21CIP1/WAF1 expression (p = 0.005). Importantly, double negativity for p21CIP1/WAF1 and p27Kip1 correlated significantly with PD-L1 (p < 0.001), SKP2 (p = 0.002), and Ki-67 (p = 0.002).

CONCLUSIONS

we have demonstrated the role of the SKP2-p27/p21 axis in intrinsic PD-L1-enhanced cell cycle progression. Inhibitors of SKP2 expression can alleviate resistance to ICPIs.

LINC01426 aggravates the malignant progression of glioma through miR-661/Mdm2 axis

BACKGROUND

Long intergenic non-protein coding RNA 1426 (LINC01426) is up-regulated in glioma and functions as a tumor promoter. However, the role of LINC01426 in glioma required further exploration. Therefore, this article mainly studied the role and possible mechanism of LINC01426 in glioma.

METHODS

The area under the receiver operating characteristic curve was used to determine the diagnostic value of LINC01426. The effect of LINC01426 on tumor growth was analyzed by tumorigenesis assay and immunohistochemical analysis. Bioinformatics analysis, dual-luciferase assay, RNA pull-down, Pearson test, and real-time quantitative PCR (RT-qPCR) were applied to verify the relationship between target genes. The expressions and effects of LINC01426, miR-661 and MDM2 proto-oncogene (Mdm2) in glioma were examined by bioinformatics analysis combined with molecular and functional experiments (RT-qRCR, 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide, clone formation, BrdU, flow cytometry). The expressions of proliferation and apoptosis-related proteins were determined by Western blot.

RESULTS

LINC01426, which was high-expressed in glioma and was related to poor prognosis, could be used as a diagnostic marker for glioma. SiLINC01426 inhibited the malignant phenotype of glioma cells in vitro and attenuated tumor growth and PCNA expression in vivo, while the effects of LINC01426 were the opposite. LINC01426 targeted and inversely correlated with miR-661, which was low-expressed in glioma. MiR-661 inhibitor evidently overturned the effect of siLINC01426 on biological functions, proliferation, and apoptosis-related proteins of glioma cells. Mdm2 bound to miR-661. Moreover, siMdm2 reversed the effects of miR-661 inhibitor on the biological characteristics and Mdm2/p53/p21 expression of glioma cells.

CONCLUSION

LINC01426 aggravated the malignant progression of glioma through miR-661/Mdm2 axis.

Kalantuboside B induced apoptosis and cytoprotective autophagy in human melanoma A2058 cells: An in vitro and in vivo study

Kalantuboside B (KB), a natural bufadienolide derivative extracted from the succulent plant Kalanchoe tubiflora, is well-known for its cardiotonic, immunomodulatory, and anti-inflammatory properties. In this study, we tested in vitro and in vivo anti-cancer efficacy with low concentrations of KB (5-30 ng/mL; 8.7-52.2 nM) on A2058 melanoma cells; and for the molecular mechanisms that underlie them. KB significantly inhibited the cell viability and colony formation via arresting the cell cycle at G2/M phase. There was an association with a decrease in Cyclin A/B1, Cdc25C, and Cdc2 expressions. Further, this treatment indicated the induction of apoptosis, DNA fragmentation, cytochrome c release, and caspase-3, -8, -9, and -12 activation, and PARP cleavage, which shows that mitochondrial, death-receptor, and ER-stress signaling pathways are involved. KB-induced autophagy was apparent from enhanced LC3-II accumulation, GFP-LC3 puncta, and AVO formation. Surprisingly, KB-mediated cell death was potentiated by 3-MA and CQ to suggest the role of autophagy as a cytoprotective mechanism. Moreover, KB-treated A2058 cells enhanced intracellular ROS generation and antioxidant NAC prevented apoptosis and reversed cytoprotective autophagy. Interestingly, KB-induced apoptosis (PARP cleavage) and cytoprotective autophagy (LC3-II accumulation) were mediated by the up-regulation of the ERK signaling pathway. It was also shown that KB promoted cytoprotective autophagy by a calcium dependent-p53 downregulation pathway. In vivo data showed that KB suppressed tumor growth significantly in A2058-xenografted nude mice. A Western blot indicated cell-cycle inhibition (cyclin A reduction), apoptosis induction (PARP cleavage and Bcl-2 inhibition), and cytoprotective autophagy (LC3-II upregulation and p53 downregulation) in KB-treated A2058-xenografted mice. Our findings suggested that KB-induced ROS pathway plays a role in mediating the apoptosis and cytoprotective autophagy in human melanoma cells. Thus, KB is considered to be a putative anti-tumor agent.

The role of FOXP3 in the development and metastatic spread of breast cancer

The transcription factor FOXP3 is widely known for its role in the development and function of immunoregulatory T cells. However, it has been discovered recently that FOXP3 is also expressed in epithelial cells of the normal human breast, ovary and prostate. Aggressive cancer of these epithelial tissues often correlates with abnormal expression of FOXP3, which can be either absent or underexpressed at transcript or protein levels. It is becoming clear that this failure of normal FOXP3 expression can result in dysregulation of the expression of a range of oncogenes which have been implicated in the development and metastasis of cancer. Recent evidence suggests that FOXP3 might also regulate chemokine receptor expression, providing a possible explanation for the chemokine-driven, tissue-specific spread that is characteristic of many cancers. This review first summarises the general structure, function and properties of FOXP3. This is followed by an analysis of the tumour-suppressive properties of this transcription factor, with particular reference to the development and chemokine-mediated spread of human breast cancer. A final section focuses on potential applications of this new knowledge for therapeutic intervention.

A simple immunohistochemical panel comprising 2 conventional markers, Ki67 and p53, is a powerful tool for predicting patient outcome in luminal-type breast cancer

BACKGROUND

Ki67 is widely used in order to distinguish the "A" and "B" subtypes of luminal-type breast cancer. This study aimed to validate the prognostic value of adding p53 to Ki67 for characterizing luminal-type breast cancer.

METHODS

Immunostaining for Ki67, p53, and the molecular markers HER2, CK5/6, CK14, EGFR, FOXA1, GATA3, and P-cadherin was examined hormone receptor (HR)-positive cancer tissues from 150 patients. The prognostic value of an immunohistochemical panel comprising Ki67 and p53 was compared with that of the single Ki67 labeling index (LI), and uni- and multivariate analyses were performed.

RESULTS

Division of the patients based on the immunohistochemistry results into favorable- (low Ki67 LI, p53-negative) and unfavorable- (high Ki67 LI and/or p53-positive) phenotype groups yielded distinctly different Kaplan-Meier's curves of both disease-free (P<0.0001) and overall survival (P=0.0007). These differences were much more distinct than those between the corresponding low Ki67 LI vs. high Ki67LI curves. While the prognostic values of the other molecular markers were not significant, combined Ki67-p53 status was an independent prognostic factor by multivariate analysis.

CONCLUSION

These data indicate that an immunohistochemical panel comprising Ki67 and p53 is a practical tool for management of patients with HR-positive breast cancer.

Association between AgNORs and Immunohistochemical Expression of ER, PR, HER2/neu, and p53 in Breast Carcinoma

Settings. Despite the limited diagnostic utility of AgNORs (argyrophilic nucleolar organiser region-associated proteins) for individual breast lesions, AgNOR analysis bears a significant potential for characterizing cell proliferative activity of breast lesions. Methodology. The present study investigated the relationship between mean AgNORs count and immunohistochemical expression of ER, PR, HER2/neu, and p53 in breast carcinoma in serial paraffin sections from 137 breast carcinomas. Twenty control cases of benign breast lesions were included. Results. Mean AgNOR counts correlated significantly inversely with hormone estrogen receptors (ER), Progesterone receptors (PR), and p53 immunohistochemical expression, denoting P values of 0.05, 0.01, and 0.001, respectively. No significant correlation was found between mean AgNOR counts and HER2/neu, P = 0.9. Mean AgNOR count was significantly higher in grade II tumor cells. We conclude that mean AgNOR counts correlate with ER, PR, and P53 tumor markers in breast carcinomas. Conclusion. We recommend the use of mean AgNOR count for accurate reporting of breast carcinomas, as well as prediction of ER, PR, and P53 in routine paraffin sections.

Honokiol, a chemopreventive agent against skin cancer, induces cell cycle arrest and apoptosis in human epidermoid A431 cells

Honokiol is a plant lignan isolated from bark and seed cones of Magnolia officinalis. Recent studies from our laboratory indicated that honokiol pretreatment decreased ultraviolet B-induced skin cancer development in SKH-1 mice. The aim of the present investigation was to study the effects of honokiol on human epidermoid squamous carcinoma A431 cells and to elucidate possible mechanisms involved in preventing skin cancer. A431 cells were pretreated with different concentrations of honokiol for a specific time period and investigated for effects on apoptosis and cell cycle analysis. Treatment with honokiol significantly decreased cell viability and cell proliferation in a concentration- and time-dependent manner. Honokiol pretreatment at 50 μmol/L concentration induced G0/G1 cell cycle arrest significantly ( P < 0.05) and decreased the percentage of cells in the S and G2/M phase. Honokiol down-regulated the expression of cyclin D1, cyclin D2, Cdk2, Cdk4 and Cdk6 proteins and up-regulated the expression of Cdk's inhibitor proteins p21 and p27. Pretreatment of A431 cells with honokiol leads to induction of apoptosis and DNA fragmentation. These findings indicate that honokiol provides its effects in squamous carcinoma cells by inducing cell cycle arrest at G0/G1 phase and apoptosis.

Adjuvant sequencing of tamoxifen and anastrozole is superior to tamoxifen alone in postmenopausal women with low proliferating breast cancer

PURPOSE

To assess the predictive value of Ki67 expression in postmenopausal hormone receptor-positive early-breast cancer patients, who were either treated with adjuvant tamoxifen (TAM) alone or with TAM followed by anastrozole (ANA).

EXPERIMENTAL DESIGN

Expression of Ki67 was determined centrally by immunohistochemistry on whole tissue sections of postmenopausal endocrine-responsive breast cancers from patients who had been enrolled in the prospectively randomized Austrian Breast and Colorectal Cancer Study Group Trial 8, and had received TAM for 5 years, or TAM for 2 years followed by ANA for 3 years. Ki67 expression was evaluated both as a continuous variable and dichotomized to low (≤10%) and high (>10%). Recurrence-free survival (RFS) and overall survival (OS) were analyzed using Cox models adjusted for clinical and pathologic parameters.

RESULTS

Patients with a high Ki67 expression (394/1,587; 23%) had a significantly shorter RFS (adjusted HR for recurrence = 1.90, 95% CI: 1.37-2.64, P = 0.0001) and OS (adjusted HR for death = 1.78, 95% CI: 1.18-2.70, P = 0.006). In women with breast tumors expressing medium or high ER levels (n = 1,438), the interaction between Ki67 and adjuvant endocrine treatment was significant for RFS (P = 0.03). TAM followed by ANA was superior to TAM alone in patients with low Ki67 (adjusted HR = 0.53, 95% CI: 0.34-0.83, P = 0.005) but not in high Ki67 disease (adjusted HR = 1.18, 95% CI: 0.66-1.89, P = 0.68).

CONCLUSIONS

Adjuvant sequencing of TAM and ANA is superior to TAM alone, particularly in postmenopausal women with medium or high ER expressing, low proliferating breast cancer.

The relationship between transcription initiation RNAs and CCCTC-binding factor (CTCF) localization

BACKGROUND

Transcription initiation RNAs (tiRNAs) are nuclear localized 18 nucleotide RNAs derived from sequences immediately downstream of RNA polymerase II (RNAPII) transcription start sites. Previous reports have shown that tiRNAs are intimately correlated with gene expression, RNA polymerase II binding and behaviors, and epigenetic marks associated with transcription initiation, but not elongation.

RESULTS

In the present work, we show that tiRNAs are commonly found at genomic CCCTC-binding factor (CTCF) binding sites in human and mouse, and that CTCF sites that colocalize with RNAPII are highly enriched for tiRNAs. To directly investigate the relationship between tiRNAs and CTCF we examined tiRNAs originating near the intronic CTCF binding site in the human tumor suppressor gene, p21 (cyclin-dependent kinase inhibitor 1A gene, also known as CDKN1A). Inhibition of CTCF-proximal tiRNAs resulted in increased CTCF localization and increased p21 expression, while overexpression of CTCF-proximal tiRNA mimics decreased CTCF localization and p21 expression. We also found that tiRNA-regulated CTCF binding influences the levels of trimethylated H3K27 at the alternate upstream p21 promoter, and affects the levels of alternate p21 (p21alt) transcripts. Extending these studies to another randomly selected locus with conserved CTCF binding we found that depletion of tiRNA alters nucleosome density proximal to sites of tiRNA biogenesis.

CONCLUSIONS

Taken together, these data suggest that tiRNAs modulate local epigenetic structure, which in turn regulates CTCF localization.

Alpha-santalol, a chemopreventive agent against skin cancer, causes G2/M cell cycle arrest in both p53-mutated human epidermoid carcinoma A431 cells and p53 wild-type human melanoma UACC-62 cells

Background

α-Santalol, an active component of sandalwood oil, has shown chemopreventive effects on skin cancer in different murine models. However, effects of α-santalol on cell cycle have not been studied. Thus, the objective of this study was to investigate effects of α-santalol on cell cycle progression in both p53 mutated human epidermoid carcinoma A431 cells and p53 wild-type human melanoma UACC-62 cells to elucidate the mechanism(s) of action.

Methods

MTT assay was used to determine cell viability in A431 cells and UACC-62; fluorescence-activated cell sorting (FACS) analysis of propidium iodide staining was used for determining cell cycle distribution in A431 cells and UACC-62 cells; immunoblotting was used for determining the expression of various proteins and protein complexes involved in the cell cycle progression; siRNA were used to knockdown of p21 or p53 in A431 and UACC-62 cells and immunofluorescence microscopy was used to investigate microtubules in UACC-62 cells.

Results

α-Santalol at 50-100 μM decreased cell viability from 24 h treatment and α-santalol at 50 μM-75 μM induced G₂/M phase cell cycle arrest from 6 h treatment in both A431 and UACC-62 cells. α-Santalol altered expressions of cell cycle proteins such as cyclin A, cyclin B1, Cdc2, Cdc25c, p-Cdc25c and Cdk2. All of these proteins are critical for G₂/M transition. α-Santalol treatment up-regulated the expression of p21 and suppressed expressions of mutated p53 in A431 cells; whereas, α-santalol treatment increased expressions of wild-type p53 in UACC-62 cells. Knockdown of p21 in A431 cells, knockdown of p21 and p53 in UACC-62 cells did not affect cell cycle arrest caused by α-santalol. Furthermore, α-santalol caused depolymerization of microtubules similar to vinblastine in UACC-62 cells.

Conclusions

This study for the first time identifies effects of α-santalol in G₂/M phase arrest and describes detailed mechanisms of G₂/M phase arrest by this agent, which might be contributing to its overall cancer preventive efficacy in various mouse skin cancer models.

Are the pure in situ breast ductal carcinomas and those associated with invasive carcinoma the same?

It has been reported that pure ductal carcinoma in situ of the breast has morphologic differences from the in situ component of the invasive ductal carcinoma, as well estrogen and progesterone receptors expression according to their cytokeratin expression. However, there is no data comparing other tumor markers without using the cytokeratin expression. The objective of this study is to compare the expression of estrogen receptor (ER) and progesterone receptor (PR), HER-2/neu, p53, and Ki67 between pure ductal in situ carcinoma (pDCIS) and the in situ component of the invasive ductal carcinoma (DCIS + IDC) of the breast, and the in situ component to the invasive component of the same tumor (DCIS + IDC). The immunohistochemistry expression of the tumor markers was performed in 45 cases of pDCIS and DCIS + IDC, yielding a total of 90 cases. Statistical analysis was carried out using Fisher exact test, having a P < 0.05, and Kappa index (kappa) to assess intratumoral concordance. In DCIS + IDC, the in situ and invasive components did not show a significant difference and Kappa index (kappa) was high (0.7-1) for positive and negative expression. ER and PR were significantly different between the pDCIS and DCIS + IDC (ER: 86.7 vs. 66.7% P = 0.04; PR: 80% vs. 55.6% P = 0.02). These findings suggest that in situ component of DCIS + IDC and pDCIS are distinct conditions.

Oligonucleotide probe array for p53 gene alteration analysis in DNA from formalin-fixed paraffin-embedded breast cancer tissues

Mutations in the TP53 tumor-suppressor (p53) gene represent the most common molecular changes in various malignancies, including breast cancer (BC). We sequenced the p53 gene in DNA extracted from archival paraffin-embedded BC tissues and compared the results obtained from direct sequencing with those obtained by oligonucleotide probe array (OPA). DNA was extracted from 34 samples. OPA correctly detected 13 genetic alterations in 14 cases, with a mutation frequency of 41.2%. No changes were detected in exons 3, 4, 9, 10, and 11 and no polymorphisms were found. Direct manual sequencing in which DNA was amplified by PCR showed 21 genetic mutations in 19 (55.9%) cases. Eight mutations were identified by both OPA and PCR methods. Although OPA detected fewer gene alterations than direct sequencing, the difference was not significant (P= 0.11). In conclusion, the OPA may be safely used to identify individual genetic variations of human p53 gene in BC specimens.

FOXP3 up-regulates p21 expression by site-specific inhibition of histone deacetylase 2/histone deacetylase 4 association to the locus

p21 loss has been implicated in conferring oncogenic activity to known tumor suppressor gene KLF4 and cancer drug tamoxifen. Regulators of p21, therefore, play critical roles in tumorigenesis. Here, we report that X-linked tumor suppressor FOXP3 is essential for p21 expression in normal epithelia and that lack of FOXP3 is associated with p21 down-regulation in breast cancer samples. A specific FOXP3 binding site in the intron 1 is essential for p21 induction by FOXP3. FOXP3 specifically inhibited binding of histone deacetylase 2 (HDAC2) and HDAC4 to the site and increased local histone H3 acetylation. Short hairpin RNA silencing of either HDAC2 or HDAC4 is sufficient to induce p21 expression. Our data provides a novel mechanism for transcription activation by FOXP3 and a genetic mechanism for lack of p21 in a large proportion of breast cancer.

Expression of Akt and Mdm2 in human esophageal squamous cell carcinoma

The Akt-Mdm2 pathway plays an important role in carcinogenesis in a variety of malignant tumors. However, the Akt-Mdm2 pathway in esophageal squamous cell carcinoma (ESCC) has not been fully studied. We investigated the proteins and mRNA expression of Akt and Mdm2 to elucidate the roles of these proteins in ESCC. We also examined the effect of Akt knockdown on Mdm2 expression in ESCC cells. ESCC tissue samples were obtained from 23 individuals who underwent surgical resection with no preoperative treatment. Akt1-3 and Mdm2 gene and protein expression were analyzed. The effect of siRNA-mediated Akt knockdown on Mdm2 expression was also studied, using ESCC cell lines. Akt1 and Mdm2 immunoreactivity was detected in 77.8 and 66.7% of tumor specimen from ESCC patients, respectively. Akt1 and Mdm2 mRNA expressions were correlated and significantly elevated in tumor tissue (p<0.0001 and p<0.05, respectively). The siRNA-targeted reduction of each Akt isoform reduced Mdm2 protein expression. The overexpression of Akt1 and Mdm2 may be related to esophageal carcinogenesis. Furthermore, Akt expression regulates Mdm2 expression, which may in turn regulate the function of wild-type p53. These results may provide the basis for future preventative or clinical therapies for esophageal cancer.

Prognostic and predictive value of centrally reviewed Ki-67 labeling index in postmenopausal women with endocrine-responsive breast cancer: results from Breast International Group Trial 1-98 comparing adjuvant tamoxifen with letrozole

PURPOSE

To evaluate the prognostic and predictive value of Ki-67 labeling index (LI) in a trial comparing letrozole (Let) with tamoxifen (Tam) as adjuvant therapy in postmenopausal women with early breast cancer.

PATIENTS AND METHODS

Breast International Group (BIG) trial 1-98 randomly assigned 8,010 patients to four treatment arms comparing Let and Tam with sequences of each agent. Of 4,922 patients randomly assigned to receive 5 years of monotherapy with either agent, 2,685 had primary tumor material available for central pathology assessment of Ki-67 LI by immunohistochemistry and had tumors confirmed to express estrogen receptors after central review. The prognostic and predictive value of centrally measured Ki-67 LI on disease-free survival (DFS) were assessed among these patients using proportional hazards modeling, with Ki-67 LI values dichotomized at the median value of 11%.

RESULTS

Higher values of Ki-67 LI were associated with adverse prognostic factors and with worse DFS (hazard ratio [HR; high:low] = 1.8; 95% CI, 1.4 to 2.3). The magnitude of the treatment benefit for Let versus Tam was greater among patients with high tumor Ki-67 LI (HR [Let:Tam] = 0.53; 95% CI, 0.39 to 0.72) than among patients with low tumor Ki-67 LI (HR [Let:Tam] = 0.81; 95% CI, 0.57 to 1.15; interaction P = .09).

CONCLUSION

Ki-67 LI is confirmed as a prognostic factor in this study. High Ki-67 LI levels may identify a patient group that particularly benefits from initial Let adjuvant therapy.

The molecular basis of genistein-induced mitotic arrest and exit of self-renewal in embryonal carcinoma and primary cancer cell lines

Background

Genistein is an isoflavonoid present in soybeans that exhibits anti-carcinogenic properties. The issue of genistein as a potential anti-cancer drug has been addressed in some papers, but comprehensive genomic analysis to elucidate the molecular mechanisms underlying the effect elicited by genistein on cancer cells have not been performed on primary cancer cells, but rather on transformed cell lines. In the present study, we treated primary glioblastoma, rhabdomyosarcoma, hepatocellular carcinoma and human embryonic carcinoma cells (NCCIT) with μ-molar concentrations of genistein and assessed mitotic index, cell morphology, global gene expression, and specific cell-cycle regulating genes. We compared the expression profiles of NCCIT cells with that of the cancer cell lines in order to identify common genistein-dependent transcriptional changes and accompanying signaling cascades.

Methods

We treated primary cancer cells and NCCIT cells with 50 μM genistein for 48 h. Thereafter, we compared the mitotic index of treated versus untreated cells and investigated the protein expression of key regulatory self renewal factors as OCT4, SOX2 and NANOG. We then used gene expression arrays (Illumina) for genome-wide expression analysis and validated the results for genes of interest by means of Real-Time PCR. Functional annotations were then performed using the DAVID and KEGG online tools.

Results

We found that cancer cells treated with genistein undergo cell-cycle arrest at different checkpoints. This arrest was associated with a decrease in the mRNA levels of core regulatory genes, PBK, BUB1, and CDC20 as determined by microarray-analysis and verified by Real-Time PCR. In contrast, human NCCIT cells showed over-expression of GADD45 A and G (growth arrest- and DNA-damage-inducible proteins 45A and G), as well as down-regulation of OCT4, and NANOG protein. Furthermore, genistein induced the expression of apoptotic and anti-migratory proteins p53 and p38 in all cell lines. Genistein also up-regulated steady-state levels of both CYCLIN A and B.

Conclusion

The results of the present study, together with the results of earlier studies show that genistein targets genes involved in the progression of the M-phase of the cell cycle. In this respect it is of particular interest that this conclusion cannot be drawn from comparison of the individual genes found differentially regulated in the datasets, but by the rather global view of the pathways influenced by genistein treatment.

Decreased chicken ovalbumin upstream promoter transcription factor II expression in tamoxifen-resistant breast cancer cells

Tamoxifen (TAM) is successfully used for the treatment and prevention of breast cancer. However, many patients that are initially TAM responsive develop tumors that are antiestrogen/TAM resistant (TAM-R). The mechanism behind TAM resistance in estrogen receptor alpha (ERalpha)-positive tumors is not understood. The orphan nuclear receptor chicken ovalbumin upstream promoter transcription factor (COUP-TF)-I interacts directly with 4-hydroxytamoxifen (4-OHT)- and estradiol (E(2))-occupied ERalpha, corepressors NCoR and SMRT, and inhibit E(2)-induced gene transcription in breast cancer cells. Here we tested the hypothesis that reduced COUP-TFI and COUP-TFII correlate with TAM resistance. We report for the first time that COUP-TFII, but not COUP-TFI, is reduced in three antiestrogen/TAM-R cell lines derived from TAM-sensitive (TAM-S) MCF-7 human breast cancer cells and in MDA-MB-231 cells compared with MCF-7. ERalpha and ERbeta protein expression was not different between TAM-S and TAM-R cells, but progesterone receptor (PR) was decreased in TAM-R cells. Further, E(2) increased COUP-TFII transcription in MCF-7, but not TAM-R, cells. Importantly, reexpression of COUP-TFII in TAM-S cells to levels comparable to those in MCF-7 was shown to increase 4-OHT-mediated growth inhibition and increased apoptosis. Conversely, knockdown of COUP-TFII in TAM-S MCF-7 cells blocked growth inhibitory activity and increased 4-OHT agonist activity. 4-OHT increased COUP-TFII-ERalpha interaction approximately 2-fold in MCF-7 cells. COUP-TFII expression in TAM-R cells also inhibited 4-OHT-induced endogenous PR and pS2 mRNA expression. These data indicate that reduced COUP-TFII expression correlates with acquired TAM resistance in human breast cancer cell lines and that COUP-TFII plays a role in regulating the growth inhibitory activity of TAM in breast cancer cells.

The role of cell cycle regulatory proteins in the pathogenesis of melanoma

The transformation of melanocytes to melanoma cells is characterised by abnormal proliferation resulting from alterations in cell cycle regulatory mechanisms. This occurs through alterations in the two major cell cycle regulatory pathways, the retinoblastoma (Rb) and p53 tumour suppressor pathways. This review summarises the current knowledge of alterations in these two pathways at G1/S transition and specifically the role of the key cell cycle regulatory proteins pRb, p16INK4a (p16), cyclin D1, p27Kip1 (p27), p53 and p21Waf1/Cip1 (p21) in the pathogenesis of melanoma. It also considers their prognostic significance. Current data indicate that alterations of cyclin kinase inhibitor (cdki) levels are implicated in the pathogenesis of melanoma and may be useful prognostic markers. However, large validation studies linked to comprehensive clinical follow up data are necessary to clarify the prognostic significance of cell cycle regulatory proteins in individual patients.

RB family members as predictive and prognostic factors in human cancer

The retinoblastoma family members--pRb, pRb2/p130 and p107--are tumor suppressor genes involved in controlling four major cellular processes: growth arrest, apoptosis, differentiation and angiogenesis. Molecular genetic studies have identified abnormalities of these tumor suppressor genes in a large proportion of human cancers. These genetic alterations have emerged as significant factors in the pathogenesis and progression of many types of tumors and are therefore likely to provide relevant information to assess risk in cancer patients. There is a pressing clinical need to identify prognostic and predictive factors for patients with cancer, because there is an undeniable importance in being able to determine which patients will have a favorable outcome without further therapy (prognostic factor) and which will need some additional treatment (predictive factor). This review examines the predictive and/or prognostic role of each retinoblastoma family member in human cancer.

Regulation of the p14ARF-Mdm2-p53 pathway: an overview in breast cancer

Knowledge of the roles of proteins that are abnormally suppressed or activated due to mutation in the DNA sequences of the common tumor suppressor genes, p14ARF and p53, is critical to the understanding the pathogenesis of breast cancer. Mdm2 is a mediator for the function of both p14ARF and p53. In this review article factors including Pokemon, Geminin, Twist, and Apigenin, which control the action of individual proteins in the p14ARF-Mdm2-p53 pathway in breast cancer as well the consequences of mutation 7 of p53 are discussed. The complexity of interaction of components of the pathway and the underlying development of cancer is emphasized. Opportunities for future therapeutic innovations are indicated.

Prognostic relevance of disseminated tumor cells in the bone marrow and biological factors of 265 primary breast carcinomas

Introduction

The prognostic significance of disseminated tumor cells in the bone marrow (DTC-BM) of breast cancer patients has been demonstrated in many studies. Yet, it is not clear which of the primary tumors' biological factors predict hematogenous dissemination. We therefore examined 'tissue micro arrays' (TMAs) of 265 primary breast carcinomas from patients with known bone marrow (BM) status for HER2, Topoisomerase IIα (Top IIa), Ki 67, and p53.

Methods

BM analysis was performed by cytospin preparation and immunocytochemical staining for cytokeratin (CK). TMAs were examined by immunohistochemistry (IHC) for HER2, Top IIa, Ki 67 and p53, and fluorescence in situ hybridization (FISH) for HER2.

Results

HER2 (2+/3+) was positive in 35/167 (21%) cases (FISH 24.3%), Top IIa (>10%) in 87/187 (46%), Ki 67 in 52/184 (28%) and p53 (>5%) in 61/174 cases (34%). Of 265 patients, 68 (25.7%) showed DTC-BM with a median of 2/2 × 10⁶ cells (1 to 1,500). None of the examined factors significantly predicted BM positivity. Significant correlation was seen between HER2 IHC and Top IIa (p = 0.06), Ki 67 (p = 0.031), and p53 (p < .001). Top IIa correlated with Ki 67 and p53, and Ki 67 also with p53 (p = 0.004). After a median follow-up of 60.5 months (7 to 255), the presence of DTC-BM showed prognostic relevance for overall survival (p = 0.03), whereas HER2 (IHC, p = 0.04; FISH, p = 0.03) and Ki 67 (p = 0.04) correlated with disease free survival, and HER2 with distant disease free survival (IHC, p = 0.06; FISH, p = 0.05).

Discussion

The congruence of the examined factors' expression rates indicates a causal line of suppressor, proliferation, and mitosis markers, and growth factor receptors. Hematogenous tumor cell spread seems to be an independent process. The examination of these factors on DTC-BM is the aim of ongoing research.