Expression of the bcl-2 gene family in normal and malignant breast tissue: low bax-alpha expression in tumor cells correlates with resistance towards apoptosis

Potential anticancer effect of free and nanoformulated Deferasirox for breast cancer treatment: in-vitro and in-vivo evaluation

BACKGROUND

Breast cancer (BC) stands as the second-leading cause of mortality among women worldwide. Many chemotherapeutic treatments for BC come with significant adverse effects. Additionally, BC is recognized as one of the most resistant forms of malignancy to treatment. Consequently, there exists a critical need for innovative therapeutic agents that are both highly effective and exhibit reduced toxicity and side effects for patients. Deferasirox (DFX), an iron-chelating drug approved by the FDA for oral use, emerges as a promising contender in the fight against BC proliferation. DFX, primarily administered orally, is utilized to address chronic iron excess resulting from blood transfusions, and it is the inaugural treatment for chronic iron overload syndrome. However, DFX encounters limitations due to its poor water solubility.

AIM

This study aimed at incorporating DFX into lipid nanocapsules (DFX-LNCs) followed by investigating the anticancer effect of the DFX nanoform as compared to free DFX in-vitro and on an orthotopic BC mouse model in-vivo.

METHODS

The DFX-LNCs was prepared and imaged using TEM and also characterized in terms of particle size (PS), zeta potential (ZP), and polydispersity index (PDI) using DLS. Moreover, drug release, cytotoxicity, and anticancer effect were assessed in-vitro, and in-vivo.

RESULTS

The results revealed that DFX-LNCs are more cytotoxic than free DFX with IC50 of 4.417 µg/ml and 16.114 µg/ml, respectively, while the plain LNCs didn't show any cytotoxic effect on the 4T1 cell line (IC50 = 122.797 µg/ml). Besides, the apoptotic effect of DFX-LNCs was more pronounced than that of free DFX, as evidenced by Annexin V/PI staining, increased BAX expression, and decreased expression of BcL-2. Moreover, DFX-LNCs showed a superior antitumor effect in-vivo with potent antioxidant and anti-proliferative effects.

CONCLUSION

The newly developed DFX nanoform demonstrated a high potential as a promising therapeutic agent for BC treatment.

A Signature of Three Apoptosis-Related Genes Predicts Overall Survival in Breast Cancer

Background

The commonest malignancy in women is known as breast cancer (BC). Numerous studies demonstrated that apoptosis appears to be critical to the management and clinical outcome of BC patients. The purpose of this study is to explore the potential connection between apoptosis and BC and establish the apoptosis-associated gene signature in BC.

Methods

The data of BC patient transcripts and related clinical information comes from the Cancer Genome Atlas Database (TCGA), and the genes related to apoptosis come from the Molecular Characterization Database (MSigDB). We identified the abnormally expressed apoptosis-related genes in BC samples. The optimal apoptosis-related genes screened by Cox regression analysis were designed to construct a prognostic model for predicting BC patients. Using the Nom Chart to Predict 1-Year, 3-Year, and 5-Year overall survival for BC patients. The gene signature-related functional pathways were explored by gene set enrichment analysis (GSEA).

Results

Three genes [alpha subunit of the interleukin 3 receptor (IL3RA), apoptosis-inducing factor mitochondrial-associated 1 (AIFM1), and phosphatidylinositol-3 kinase catalytic alpha (PIK3CA)] correlated with apoptosis were shown to be strongly linked to the overall survival of BC. Survival analysis shows that the risk score is directly proportional to the poor prognosis of BC patients. Risk assessment based on three genetic characteristics (age, pathological stage N, and pathological stage M) can independently predict the prognosis of patients with BC. The Nom chart is most suitable for assessing the long-term survival rate of BC patients. The results of GSEA demonstrated that numerous cell cycle-related pathways were abundant in the high-risk group.

Conclusion

We constructed an apoptosis-associated gene signature in BC, which had a potential clinical application prospect for BC patients.

Association of XRCC3, XRCC4, BAX, and BCL-2 Polymorphisms with the Risk of Breast Cancer

Background

Breast cancer is the most common malignancy in women. Genetic risk factors associated with breast cancer incidence have been identified.

Aims

This study is aimed at determining the association of XRCC3 Thr241Met (rs861539), XRCC4 G(-1394) T (rs6869366) DNA repair and BAX G(-248) A (rs4645878), and BCL2 C(-938) A (rs2279115) apoptotic gene polymorphisms with breast cancer.

Materials and Methods

Genetic analysis was performed using peripheral blood samples. Gene polymorphisms were detected by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. 175 patients and 158 healthy controls were enrolled in the study.

Results

Breast cancer risk was 5.43 times more in individuals with AA genotype of Bax G(-248) A (rs4645878) (P = 0.002). The risk of metastasis was 11 times with this genotype. It was associated with 6 times more risk of having a tumor larger than 2 cm. The risk of breast cancer was 2.77 times more in individuals carrying the Met/Met genotype of XRCC3 Thr241Met (rs861539) (P = 0.009). The risk of having advanced clinical stage (stage III+IV) with the Met/Met genotype was 4 times more increased. No relationship with breast cancer was found with XRCC4 G(-1394) T (rs6869366) and BCL2 C(-938) A (rs2279115) gene polymorphisms.

Conclusion

Multicenter trials using subjects with genetic variations are needed to establish the relationship between breast cancer and single gene polymorphism.

Review of cancer cell resistance mechanisms to apoptosis and actual targeted therapies

The apoptosis pathway is a programmed cell death mechanism that is crucial for cellular and tissue homeostasis and organ development. There are three major caspase-dependent pathways of apoptosis that ultimately lead to DNA fragmentation. Cancerous cells are known to highly regulate the apoptotic pathway and its role in cancer hallmark acquisition has been discussed over the past decades. Numerous mutations in cancer cell types have been reported to be implicated in chemoresistance and treatment outcome. In this review, we summarize the mutations of the caspase-dependant apoptotic pathways that are the source of cancer development and the targeted therapies currently available or in trial.

Role of Apelin/APJ axis in cancer development and progression

Apelin is an endogenous peptide, which is expressed in a vast board of organs such as the brain, placenta, heart, lungs, kidneys, pancreas, testis, prostate and adipose tissues. The apelin receptor, called angiotensin-like-receptor 1 (APJ), is also expressed in the brain, spleen, placenta, heart, liver, intestine, prostate, thymus, testis, ovary, lungs, kidneys, stomach, and adipose tissue. The apelin/APJ axis is involved in a number of physiological and pathological processes. The apelin expression is increased in various kinds of cancer and the apelin/APJ axis plays a key role in the development of tumors through enhancing angiogenesis, metastasis, cell proliferation and also through the development of cancer stem cells and drug resistance. The apelin also stops the apoptosis of cancer cells. The apelin/APJ axis was considered in this review as an attractive therapeutic target for cancer treatment.

Anticancer Activities of Cu(II) Complex-Schiff Base and Low-Frequency Electromagnetic Fields and the Interaction Between Cu(II) Complex-Schiff Base with Bovine Serum Albumin by Spectroscopy

Cancer is the consequence of abnormal cell proliferation, which leads to the formation of abnormal mass. In this study, we aimed to determine the anticancer properties of Cu(II)-Schiff base complex and low-frequency electromagnetic field, and the interaction between BSA and Cu(II) complex. Firstly, Schiff base of the Cu(II) complex in the N,N'-dipyridoxyl(1,2 diaminobenzene) was originally synthesized. Following, the breast cancer was transplanted with the TUBO cells in vivo. Then, treatment of the cancerous mice was done by low-frequency electromagnetic field and the Cu(II)-Schiff base complex. In this project, antiproliferative activity on breast cancer cells was tested by TUBO cells using MTT assay and apoptosis properties were studied by flow cytometry. The interaction between the Cu(II)-Schiff base complex and bovine serum albumin (BSA) was checked by fluorescence and UV-vis absorbance spectroscopy. Tumor tissue investigation demonstrated that the low-frequency electromagnetic field and Cu(II)-Schiff base complex induce apoptosis and inhibit tumor growth. MTT results unveiled a cytotoxic impact on breast cancer cells. Flow cytometry analysis demonstrates that the anticancer effect of Cu(II)-Schiff base complex on breast cancer cells (MCF7) was associated with the cell cycle arrest. The results of fluorescence spectra and UV-vis absorption spectra showed that the conformation of bovine serum albumin has been changed in the presence of Cu(II)-Schiff base complex. Cu(II)-Schiff base complex and low-frequency electromagnetic field have anticancer properties. The spectroscopy method indicates the binding between Cu(II)-Schiff base complex and BSA.

Synergistic effect of phototherapy and chemotherapy on bladder cancer cells

Drug resistance as an important barrier to cancer treatment, has a close relation with alteration of cancer metabolism. Therefore, in this study the synergistic effect of phototherapy and chemotherapy were investigated on the bladder cancer cells viability. The cytotoxicity effect of blue light irradiation was measured by the MTT assay. Glucose consumption, lactate and ammonium formation were analyzed in the blue LED-irradiated cancer cells culture. Also, the expression of some genes involved in apoptosis and epithelial-mesenchymal transition was assessed using real-time PCR in comparison with the control group. The analysis of the results indicated that blue light irradiation inhibited the cell viability in a dose-dependent manner. Blue light irradiation decreased the cell viability by 7% and 19% (p < .05) in 5637 cells at doses of 8.7 J/cm² and 17.5 J/cm² in comparison with the control group respectively. Glucose consumption, lactate and ammonium formation diminished in the blue LED-irradiated 5637 cells in both doses. The real time PCR results indicated that the expression of Bax increased in blue light-irradiated cells. In addition, the cell cycle analysis showed that blue light irradiation arrested the bladder cancer in the G1 phase. Also, the effect of combination therapy on cancer cells was investigated in presence of blue light irradiation and cisplatin. The obtained results of the MTT assay indicated that blue light irradiation enhance the cytotoxicity effect of cisplatin on bladder cancer cells.

Re-inforcing the cell death army in the fight against breast cancer

Metastatic breast cancer is responsible for most breast cancer-related deaths. Disseminated cancer cells have developed an intrinsic ability to resist anchorage-dependent apoptosis (anoikis). Anoikis is caused by the absence of cellular adhesion, a process that underpins lumen formation and maintenance during mammary gland development and homeostasis. In healthy cells, anoikis is mostly governed by B-cell lymphoma-2 (BCL2) protein family members. Metastatic cancer cells, however, have often developed autocrine BCL2-dependent resistance mechanisms to counteract anoikis. In this Review, we discuss how a pro-apoptotic subgroup of the BCL2 protein family, known as the BH3-only proteins, controls apoptosis and anoikis during mammary gland homeostasis and to what extent their inhibition confers tumor suppressive functions in metastatic breast cancer. Specifically, the role of the two pro-apoptotic BH3-only proteins BCL2-modifying factor (BMF) and BCL2-interacting mediator of cell death (BIM) will be discussed here. We assess current developments in treatment that focus on mimicking the function of the BH3-only proteins to induce apoptosis, and consider their applicability to restore normal apoptotic responses in anchorage-independent disseminating tumor cells.

Biological determinants of radioresistance and their remediation in pancreatic cancer

Despite recent advances in radiotherapy, a majority of patients diagnosed with pancreatic cancer (PC) do not achieve objective responses due to the existence of intrinsic and acquired radioresistance. Identification of molecular mechanisms that compromise the efficacy of radiation therapy and targeting these pathways is paramount for improving radiation response in PC patients. In this review, we have summarized molecular mechanisms associated with the radio-resistant phenotype of PC. Briefly, we discuss the reversible and irreversible biological consequences of radiotherapy, such as DNA damage and DNA repair, mechanisms of cancer cell survival and radiation-induced apoptosis following radiotherapy. We further describe various small molecule inhibitors and molecular targeting agents currently being tested in preclinical and clinical studies as potential radiosensitizers for PC. Notably, we draw attention towards the confounding effects of cancer stem cells, immune system, and the tumor microenvironment in the context of PC radioresistance and radiosensitization. Finally, we discuss the need for examining selective radioprotectors in light of the emerging evidence on radiation toxicity to non-target tissue associated with PC radiotherapy.

Expression of the EP300, TP53 and BAX genes in colorectal cancer: Correlations with clinicopathological parameters and survival

E1A binding protein P300 (EP300), tumor protein P53 (TP53) and BCL2 associated X, apoptosis regulator (BAX) genes encode proteins which cooperate to regulate important cellular processes. The present study aimed to determine the expression levels of EP300, TP53 and BAX in colorectal cancer (CRC) and to investigate their prognostic value and association with the progression of CRC. Tumor and matched unchanged colorectal tissues were collected from 121 CRC patients. Quantitative polymerase chain reaction and immunohistochemistry were used to assess the mRNA and protein levels of the studied genes. Altered expression of the studied genes in CRC tissues was observed at both the mRNA and protein levels. The depth of invasion was associated with TP53 mRNA levels and was correlated negatively with BAX mRNA expression. Moreover, a relationship between tumor location and BAX mRNA content was noted. BAX immunoreactivity was correlated positively with the intensity of p300 immunostaining and was associated with lymph node involvement and tumor-node-metastasis (TNM) disease stage. Univariate regression analysis revealed that overexpression of p53 and BAX in CRC tissues was associated with poor patient outcome. In conclusion, dysregulation of the expression of the studied genes was found to contribute to CRC pathogenesis. The association between p300 and BAX levels suggests the existence of an interdependent regulatory mechanism of their expression. Moreover, BAX expression may be regulated alternatively, in a p53-independent manner, since the lack of correlations between expression of these factors was observed.

Molecular Portrait of the Normal Human Breast Tissue and Its Influence on Breast Carcinogenesis

Normal human breast tissue consists of epithelial and nonepithelial cells with different molecular profiles and differentiation grades. This molecular heterogeneity is known to yield abnormal clones that may contribute to the development of breast carcinomas. Stem cells that are found in developing and mature breast tissue are either positive or negative for cytokeratin 19 depending on their subtype. These cells are able to generate carcinogenesis along with mature cells. However, scientific data remains controversial regarding the monoclonal or polyclonal origin of breast carcinomas. The majority of breast carcinomas originate from epithelial cells that normally express BRCA1. The consecutive loss of the BRCA1 gene leads to various abnormalities in epithelial cells. Normal breast epithelial cells also express hypoxia inducible factor (HIF) 1α and HIF-2α that are associated with a high metastatic rate and a poor prognosis for malignant lesions. The nuclear expression of estrogen receptor (ER) and progesterone receptor (PR) in normal human breast tissue is maintained in malignant tissue as well. Several controversies regarding the ability of ER and PR status to predict breast cancer outcome remain. Both ER and PR act as modulators of cell activity in normal human breast tissue. Ki-67 positivity is strongly correlated with tumor grade although its specific role in applied therapy requires further studies. Human epidermal growth factor receptor 2 (HER2) oncoprotein is less expressed in normal human breast specimens but is highly expressed in certain malignant lesions of the breast. Unlike HER2, epidermal growth factor receptor expression is similar in both normal and malignant tissues. Molecular heterogeneity is not only found in breast carcinomas but also in normal breast tissue. Therefore, the molecular mapping of normal human breast tissue might represent a key research area to fully elucidate the mechanisms of breast carcinogenesis.

Apoptotic effect of noscapine in breast cancer cell lines

Cancer is a public health problem in the world and breast cancer is the most frequently cancer in women. Approximately 15% of the breast cancers are triple-negative. Apoptosis regulates normal growth, homeostasis, development, embryogenesis and appropriate strategy to treat cancer. Bax is a protein pro-apoptotic enhancer of apoptosis in contrast to Bcl-2 with antiapoptotic properties. Initiator caspase-9 and caspase-8 are features of intrinsic and extrinsic apoptosis pathway, respectively. NF-κB is a transcription factor known to be involved in the initiation and progression of breast cancer. Noscapine, an alkaloid derived from opium is used as antitussive and showed antitumor properties that induced apoptosis in cancer cell lines. The aim of the present study was to determine the apoptotic effect of noscapine in breast cancer cell lines compared to breast normal cell line. Three cell lines were used: i) a control breast cell line MCF-10F; ii) a luminal-like adenocarcinoma triple-positive breast cell line MCF-7; iii) breast cancer triple-negative cell line MDA-MB-231. Our results showed that noscapine had lower toxicity in normal cells and was an effective anticancer agent that induced apoptosis in breast cancer cells because it increases Bax gene and protein expression in three cell lines, while decreases Bcl-xL gene expression, and Bcl-2 protein expression decreased in breast cancer cell lines. Therefore, Bax/Bcl-2 ratio increased in the three cell lines. This drug increased caspase-9 gene expression in breast cancer cell lines and caspase-8 gene expression increased in MCF-10F and MDA-MB-231. Furthermore, it increased cleavage of caspase-8, suggesting that noscapine-induced apoptosis is probably due to the involvement of extrinsic and intrinsic apoptosis pathways. Antiapoptotic gene and protein expression diminished and proapoptotic gene and protein expression increased noscapine-induced expression, probably due to decrease in NF-κB gene and protein expression and also by increase of IκBα gene expression induced by this drug.

Comparing Two Intestinal Porcine Epithelial Cell Lines (IPECs): Morphological Differentiation, Function and Metabolism

The pig shows genetical and physiological resemblance to human, which predestines it as an experimental animal model especially for mucosal physiology. Therefore, the intestinal epithelial cell lines 1 and J2 (IPEC-1, IPEC-J2) - spontaneously immortalised cell lines from the porcine intestine - are important tools for studying intestinal function. A microarray (GeneChip Porcine Genome Array) was performed to compare the genome wide gene expression of IPECs. Different significantly up-regulated pathways were identified, like “lysosome”, “pathways in cancer”, “regulation of actin cytoskeleton” and “oxidative phosphorylation” in IPEC-J2 in comparison to IPEC-1. On the other hand, “spliceosome”, “ribosome”, “RNA-degradation” and “tight junction” are significantly down-regulated pathways in IPEC-J2 in comparison to IPEC-1. Examined pathways were followed up by functional analyses. ATP-, oxygen, glucose and lactate-measurement provide evidence for up-regulation of oxidative phosphorylation in IPEC-J2. These cells seem to be more active in their metabolism than IPEC-1 cells due to a significant higher ATP-content as well as a higher O₂- and glucose-consumption. The down-regulated pathway “ribosome” was followed up by measurement of RNA- and protein content. In summary, IPEC-J2 is a morphologically and functionally more differentiated cell line in comparison to IPEC-1. In addition, IPEC-J2 cells are a preferential tool for in vitro studies with the focus on metabolism.

Quinolone-indolone conjugate induces apoptosis by inhibiting the EGFR-STAT3-HK2 pathway in human cancer cells

The epidermal growth factor receptor (EGFR) is involved in the proliferation of human tumors and is an effective target for the treatment of cancer. In the present study, a novel quinolone-indolone conjugate, QIC1 [9-Fluoro-3,7-dihydro-3-methyl-10-(4-methyl -1-piperazinyl) -6-(2-oxo-1,2-dihydro-indol-3-ylidenemethyl) -7-oxo-2H-(1,4) oxazino(2,3,4-ij)quinoline], which targeted EGFR, was synthesized in order to investigate the anticancer activity and the potential mechanisms underlying the effect of this compound in human cancer cells. Using MTT assays it was observed that QIC1 inhibited the growth of HepG2 human hepatoma cells, MCF7 human breast cancer cells, HeLa human cervical cancer cells and A549 human lung adenocarcinoma cells. QIC1 arrested cell cycle progression at the G2/M phase in HepG2 cells. QIC1 inhibited the synthesis of DNA in A549 cells. In addition, it resulted in cell apoptosis, in association with increased expression of Bax and reduced expression of Bcl-2. Further analyses demonstrated that QIC1 attenuated the activity of EGFR, and the downstream signal transducer and activator of transcription 3 (STAT3)-mediated hexokinase II (HK2) signaling pathways. Furthermore, QIC1 exhibited antiproliferative effects in MCF7/DOX human doxorubicin-resistant breast cancer cells and also enhanced the anticancer activity of doxorubicin in these cells. In conclusion, the inhibition of proliferation and the induction of apoptosis was associated with reduced expression of phospho-EGFR-phospho-STAT3-HK2. The present results suggest a potential role for QIC1 in the treatment of human cancer.

2,2'-diphenyl-3,3'-diindolylmethane: a potent compound induces apoptosis in breast cancer cells by inhibiting EGFR pathway

Despite recent advances in medicine, 30-40% of patients with breast cancer show recurrence underscoring the need for improved effective therapy. In this study, by in vitro screening we have selected a novel synthetic indole derivative 2,2'-diphenyl-3,3'-diindolylmethane (DPDIM) as a potential anti- breast cancer agent. DPDIM induces apoptosis both in vitro in breast cancer cells MCF7, MDA-MB 231 and MDA-MB 468 and in vivo in 7,12-dimethylbenz[α]anthracene (DMBA) induced Sprague-Dawley (SD) rat mammary tumor. Our in vitro studies show that DPDIM exerts apoptotic effect by negatively regulating the activity of EGFR and its downstream molecules like STAT3, AKT and ERK1/2 which are involved in the proliferation and survival of these cancer cells. In silico predictions also suggest that DPDIM may bind to EGFR at its ATP binding site. DPDIM furthermore inhibits EGF induced increased cell viability. We have also shown decreased expression of pro-survival factor Bcl-XL as well as increase in the level of pro-apoptotic proteins like Bax, Bad, Bim in DPDIM treated cells in vitro and in vivo. Our results further indicate that the DPDIM induced apoptosis is mediated through mitochondrial apoptotic pathway involving the caspase-cascade. To the best of our knowledge this is the first report of DPDIM for its anticancer activity. Altogether this report suggests that DPDIM could be an effective therapeutic agent for breast cancer.

A natural compound from Hydnophytum formicarium induces apoptosis of MCF-7 cells via up-regulation of Bax

BACKGROUND

Hydnophytum formicarium Jack is an epyphytic shrub that belongs to the family of Rubiaceae and is native to the tropical rain forests of the Asean region, which includes Malaysia. A flavanoid derivative, 7, 3', 5'-trihydroxyflavanone (3HFD), isolated from H. formicarium has been reported to have cytotoxic effects on the human breast carcinoma cell line MCF-7. The aim of the current study was to investigate the mode of cell death in MCF-7 cells treated with 3HFD. A DNA fragmentation assay was conducted on isolated genomic DNA, a TUNEL assay was used to determine the mode of cell death and Western blotting was used to evaluate the expression levels of Bax and Bcl-2. Immunofluorescence staining of MCF-7 cells was also performed to confirm the up-regulation of the Bax protein.

RESULTS

The ladder pattern resulting from the DNA fragmentation assay was a multimer of 180 kb. The morphological changes of cells undergoing apoptosis were visualised by a TUNEL assay over time. The percentage of apoptotic cells increased as early as 6 hours post treatment compared to untreated cells. Western blotting revealed up-regulation of the pro-apoptotic protein Bax. However, 3HFD did not affect expression of the anti-apoptotic protein Bcl-2.

CONCLUSIONS

Our results provide evidence that plant-derived 3HFD was able to induce the apoptotic cell death of MCF-7 cells by increasing Bax expression level and makes 3HFD a promising agent for chemotherapy, which merits further study.

The anti-apoptotic protein lifeguard is expressed in breast cancer cells and tissues

Lifeguard (LFG) is an anti-apoptotic protein that inhibits Fas-mediated death in tumour cells. However, the molecular function of human LFG in the carcinogenesis of human breast cells is uncertain. We studied the expression and function of endogenous LFG in four breast cancer cell lines (MCF-7, MDA-MB-231, T-47D and HS 578T), a human breast epithelial cell line (HS 578Bst), and in healthy and cancerous breast tissues. Molecular (Western blot and RT-PCR) and immunohistochemical techniques were used to investigate the LFG expression. To investigate the breast cancer cell proliferation in the presence of Fas, we performed fluorescent cell viability assays. The possible association of Fas with LFG was analyzed by immunofluorescence microscopy. In this paper, we provide convincing evidence that LFG is overexpressed in several human breast cancer cell lines. More importantly, we found that the LFG expression correlates with high tumour grades in primary breast tumours. Finally, we demonstrated that Fas sensitivity is reduced in breast cancer cell lines expressing LFG. Our results indicated that LFG is strongly expressed in breast cancer epithelial cells. Moreover, the overexpression of LFG correlated with tumour grade and reduced Fas sensitivity. Our findings support the idea that LFG may have a role in the downregulation of apoptosis in breast cancer cells.

Clinical Significance of p53 and bcl-2 Protein Coexpression Phenotypes in Molecular Breast Cancer Subtypes of Pre-menopausal and Post-menopausal African-American Women

With the current classification of breast carcinoma into molecular subtypes with distinct prognosis and response to therapy, we sort to assess the clinical significance of p53 and bcl-2 coexpression phenotypes in invasive breast tumors and correlate this to the different molecular breast cancer subtypes in African-American women. We performed a retrospective analysis of data on p53 and bcl-2 expression. Results were correlated to molecular breast cancer subtypes, and clinicopathologic variables of prognostic significance. Our study sample included all African-American women diagnosed with breast cancer from 1998 to 2005. Twenty-seven (27.6%) per cent of cases in our study sample over-expressed p53, whereas 69.3 per cent over-expressed bcl-2 protein. A significant inverse correlation was observed between expression of p53 and bcl-2. Combined analysis of p53 and bcl-2 showed that 53.2 per cent of the tumors displayed p53(-)bcl-2(+) phenotype which was significantly associated with the luminal A subtype, whereas 11.6 per cent displayed the p53(+)bcl-2(-) phenotype which was significantly associated with the basal cell-like and Her-2/neu. Neither p53 expression nor bcl-2 expression individually or in combination were of independent prognostic significance. p53(+)bcl-2(-) phenotype is significantly correlated with the basal cell-like subtype and may be associated with the biologic aggressiveness of this cohort of molecular breast cancer.

Apoptosis and cancer: the genesis of a research field

In multicellular organisms, the total number of cells is a balance between the cell-generating effects of mitosis and cell death that is induced through apoptosis. A disruption of this delicate balance can lead to the development of cancer. This Timeline article focuses on how the field of apoptosis biology has developed in the context of its contribution to our understanding of cell death, or lack of it, in the development of malignant disease. It traces the course of research from key discoveries in fundamental biology to potential therapeutic applications.

Expression of Bcl-2 in feline lymphoma cell lines

BACKGROUND

The Bcl-2 gene is a member of the rapidly expanding Bcl-2 family of genes that regulate apoptosis. Bcl-2 has been shown to repress cell death triggered by a diverse array of stimuli, including chemotherapy and gamma irradiation.

OBJECTIVE

The purpose of this study was to determine feline Bcl-2 expression level in feline lymphoma cells using an immunoblot assay with anti-human and anti-canine Bcl-2 monoclonal antibodies.

METHODS

About 708 base pairs containing the coding sequence of the feline Bcl-2 gene were transformed into Escherichia coli. The recombinant Bcl-2 was used as a positive control for an immunoblot assay using mouse monoclonal antibodies against human and canine Bcl-2. An immunoblot assay using the monoclonal antibodies was carried out to determine the level of feline Bcl-2 expression in lymphoma and lymphocytic leukemia cell lines.

RESULTS

The recombinant feline Bcl-2 protein produced in E. coli had a molecular weight of about 26 kDa and was detected by immunoblot assay by using anti-human Bcl-2 mouse monoclonal antibody. Feline Bcl-2 expression was high in lymphoma cell lines (FL-74-UDC-1 and FT-1) and low in the cell line from peripheral blood mononuclear cells from a healthy cat (FeTJ-1) but not low in freshly isolated peripheral blood mononuclear cells from a healthy cat. The anti-human Bcl-2 mouse monoclonal antibody was found to cross-react with feline Bcl-2.

CONCLUSIONS

These results confirm the expression of Bcl-2 in T-cell lymphoma cell lines and indicate that it is suitable to detect feline Bcl-2 using an immunoblot assay. Pending further evaluation, Bcl-2 expression might be useful in the differential diagnosis of feline tumors.

Mcl-1 determines the Bax dependency of Nbk/Bik-induced apoptosis

B cell lymphoma 2 (Bcl-2) homology domain 3 (BH3)-only proteins of the Bcl-2 family are important functional adaptors that link cell death signals to the activation of Bax and/or Bak. The BH3-only protein Nbk/Bik induces cell death via an entirely Bax-dependent/Bak-independent mechanism. In contrast, cell death induced by the short splice variant of Bcl-x depends on Bak but not Bax. This indicates that Bak is functional but fails to become activated by Nbk. Here, we show that binding of myeloid cell leukemia 1 (Mcl-1) to Bak persists after Nbk expression and inhibits Nbk-induced apoptosis in Bax-deficient cells. In contrast, the BH3-only protein Puma disrupts Mcl-1-Bak interaction and triggers cell death via both Bax and Bak. Targeted knockdown of Mcl-1 overcomes inhibition of Bak and allows for Bak activation by Nbk. Thus, Nbk is held in check by Mcl-1 that interferes with activation of Bak. The finding that different BH3-only proteins rely specifically on Bax, Bak, or both has important implications for the design of anticancer drugs targeting Bcl-2.

Apoptosis in spermatocytic and usual seminomas: a light microscopic and immunohistochemical study

Despite its alarming appearance, spermatocytic seminoma virtually never metastasizes. We hypothesized that this paradox may at least be partially related to increased apoptosis compared to metastasizing germ cell tumors since high expression of proapoptotic factors correlates with indolent behavior in other tumor systems, notably CD30-positive cutaneous lymphoma, another neoplasm where phenotype and behavior do not match. We therefore compared apoptosis and apoptotic regulators in 17 spermatocytic seminomas (2 with sarcoma) and 18 usual seminomas by light microscopy and using immunostains for caspase-3, p53, bcl-2, bcl-xL, FADD, FAS and survivin. We found significantly greater numbers of apoptotic cells and activated caspase-3-positive cells in spermatocytic seminoma compared to usual seminoma (P<0.01). There was over a 10-fold range in apoptotic cells in usual seminoma but only a 4-fold variation in spermatocytic seminoma. Spermatocytic seminoma had decreased p53 expression compared to usual seminoma, with marked variation in bcl-2 expression and increased FADD. The two sarcomas in spermatocytic seminoma, however, showed decreased apoptosis and caspase-3 reactivity, with upregulation of p53 and bcl-2 and decreased FADD expression. We conclude that apoptosis, caspase-3 and FADD expression are increased in spermatocytic seminoma compared to usual seminoma. Apoptotic parameters are decreased in sarcomatous transformation of spermatocytic seminoma. The increased apoptosis of spermatocytic seminoma, possibly mediated by FAS independent activation of the death receptor pathway, may provide some insight into its excellent prognosis. The variation in apoptosis of usual seminomas merits investigation as a prognostic parameter.

Apoptosis of canine mammary tumor cells induced by small interfering RNA (siRNA) against Bcl-xL gene

The inhibition of Bcl-xL mRNA expression and the acceleration of apoptotic cell rates in canine mammary tumor cell line (CF33) by the small interfering RNA (siRNA) were analyzed. The level of Bcl-xL transcripts in CF33 was decreased when cultured with siRNA, suggesting that siRNA might inhibit the expression of Bcl-xL mRNA in the CF33. Apoptotic cell rates in CF33 cultured with siRNA in Oligofectamine medium, with double strand RNA in Oligofectamine medium, without siRNA in Oligofectamine medium and in DMEM alone were 60.9%, 30%, 28.7% and 11.6% at 48-hr incubation, respectively, when evaluated by TUNEL assay. From these results, it was suggested that canine Bcl-xL might be an anticancer target of canine tumors.

123I-labeled HIV-1 tat peptide radioimmunoconjugates are imported into the nucleus of human breast cancer cells and functionally interact in vitro and in vivo with the cyclin-dependent kinase inhibitor, p21WAF-1/Cip-1

PURPOSE

To evaluate the internalization and nuclear translocation of (123)I-tat-peptide radioimmunoconjugates in MDA-MB-468 breast cancer cells and their ability to interact with the cyclin-dependent kinase inhibitor, p21(WAF-1/Cip-1).

METHODS

Peptides [GRKKRRQRRRPPQGYGC] harboring the nuclear-localizing sequence from HIV tat domain were conjugated to anti-p21(WAF-1/Cip-1) antibodies. Immunoreactivity was assessed by Western blot using lysate from MDA-MB-468 cells exposed to EGF to induce p21(WAF-1/Cip-1). Internalization and nuclear translocation were measured. The ability of tat-anti-p21(WAF-1/Cip-1) to block G(1)-S phase arrest in MDA-MB-468 cells caused by EGF-induced p21(WAF-1/Cip-1) was evaluated. Tumor and normal tissue uptake were determined at 48 h p.i. in athymic mice implanted s.c. with MDA-MB-468 xenografts injected intratumorally with EGF.

RESULTS

There was 13.4+/-0.2% of radioactivity internalized by MDA-MB-468 cells incubated with (123)I-tat-anti-p21(WAF-1/Cip-1) and 34.6+/-3.1% imported into the nucleus. Tat-anti-p21(WAF-1/Cip-1)(8 muM) decreased the proportion of EGF-treated cells in G(1) phase from 81.9+/-0.7% to 46.1+/-0.7% (p<0.001), almost restoring the G(1) phase fraction to that of unexposed cells (25.8+/-0.2%). Non-specific tat-mouse IgG did not block EGF-induced G(1)-S phase arrest. Tumor uptake of radioactivity was higher in mice injected with EGF to induce p21(WAF-1/Cip-1) than in mice not receiving EGF (3.1+/-0.4% versus 1.8+/-0.2% ID/g; p=0.04). Western blot analysis of tumors revealed a threefold increase in the p21(WAF-1/Cip-1)/beta-actin ratio.

CONCLUSION

We conclude that intracellular and nuclear epitopes in cancer cells can be functionally targeted with tat-radioimmunoconjugates to exploit many more epitopes for imaging and radiotherapeutic applications than have previously been accessible.

Non-steroidal anti-inflammatory drugs to potentiate chemotherapy effects: from lab to clinic

Most solid tumors express the cyclooxygenase-2 (COX-2) protein, a target of NSAIDs. COX-2 overexpression in tumorsis considered a predictor of more advanced stage disease and of worse prognosis in a number of studies investigating solid malignancies. Therefore, NSAIDs are evaluated as anti-cancer drugs. NSAIDs inhibit proliferation, invasiveness of tumors, and angiogenesis and overcome apoptosis resistance in a COX-2 dependent and independent manner. This review will focus on the rationale behind NSAIDs, including selective COX-2 inhibitors, in combination with conventional chemotherapeutic drugs or novel molecular targeted drugs. Studies investigating anti-cancer effects of NSAIDs on cell lines and xenograft models have shown modulation of the Akt, NF-kappaB, tyrosine kinase and the death receptor-mediated apoptosis pathways. COX-2 expression in tumors is not yet used as biomarker in the clinic. Despite the increased risk on cardiovascular toxicity induced by selective COX-2 inhibitors, several ongoing clinical trials are still investigating the therapeutic benefits of NSAIDs in oncology. The anti-tumor effects in these trials balanced with the side effects data will define the precise role of selective COX-2 inhibitors in the treatment of cancer patients.

mda-7 gene transfer sensitizes breast carcinoma cells to chemotherapy, biologic therapies and radiotherapy: correlation with expression of bcl-2 family members

Current therapies used in the treatment of breast cancer are limited by systemic toxicity, rapid drug metabolism and intrinsic and acquired drug resistance. We have previously shown that adenoviral-mediated transfer of the melanoma differentiation-associated gene-7 (mda-7) elicits growth inhibition and apoptosis in various tumor types. Here, we evaluate the effects of Ad-mda7, alone and in combination with other therapies, against a panel of nine breast tumor cell lines and their normal counterparts; we report selective Ad-mda7-mediated p53-independent growth inhibition, G2/M cell cycle arrest, and apoptosis. In vivo, Ad-mda7 induced p53-independent tumor growth inhibition (P<0.004) in multiple xenograft models. We then evaluated the combination of Ad-mda7 with agents commonly used to treat breast cancer: radiotherapy (XRT), Tamoxifen, Taxotere, Adriamycin, and Herceptin. These agents exhibit diverse modes of action, including formation of bulky adducts, inhibition of DNA replication (Adriamycin, XRT), damage to microtubules (Taxotere), nonsteroidal estrogen antagonists (Tamoxifen), or Her2/neu receptor blockade (Herceptin). Treated with conventional anticancer drugs or radiation, MDA-7-expressing cells display additive or synergistic cytotoxicity and apoptosis that correlates with decreased BCL-2 expression and BAX upregulation. In vivo, animals that received Ad-mda7 and XRT underwent significant reduction of tumor growth (P<0.002). This is the first report of the synergistic effects of Ad-mda7 combined with chemotherapy or radiotherapy on human breast carcinoma cells.

Tocotrienol-induced cytotoxicity is unrelated to mitochondrial stress apoptotic signaling in neoplastic mammary epithelial cells

Tocotrienols and tocopherols represent the 2 subgroups within the vitamin E family of compounds, but tocotrienols display significantly greater apoptotic activity against a variety of cancer cell types. However, the exact mechanism mediating tocotrienol-induced apoptosis is not understood. Studies were conducted to determine the effects of tocotrienols on mitochondrial-stress-mediated apoptotic signaling in neoplastic +SA mammary epithelial cells grown in vitro. Exposure for 24 h to 0-20 micromol/L gamma-tocotrienol resulted in a dose-responsive increase in +SA cells undergoing apoptosis, as determined by flow cytometric analysis of Annexin V staining. However, tocotrienol-induced apoptosis was not associated with a disruption or loss of mitochondrial membrane potential, or the release of mitochondrial cytochrome c into the cytoplasm, as determined by JC-1 flow cytometric staining and ELISA assay, respectively. Interestingly, apoptotic +SA cells showed a paradoxical decrease in mitochondrial levels of pro-apoptotic proteins Bid, Bax, and Bad, and a corresponding increase in mitochondrial levels of anti-apoptotic proteins, Bcl-2 and Bcl-xL, suggesting that mitochondrial membrane stability and integrity might actually be enhanced for a limited period of time following acute tocotrienol exposure. In summary, these findings clearly demonstrate that tocotrienol-induced apoptosis occurs independently of mitochondrial stress apoptotic signaling in neoplastic +SA mammary epithelial cells.

Effect of antineoplastic drugs on the expression of Bcl-2 and Bcl-xL genes in the feline T-cell leukemia cell line

The Bcl-2 gene is the first member of a rapidly expanding family of genes that regulate apoptosis. Bcl-2 has been shown to repress cell death triggered by a diverse array of stimuli including chemotherapy and gamma-irradiation. Chemotherapy of feline lymphoma is generally carried out with antineoplastic drugs, which are reported to induce apoptosis in tumor cells. However, the precise apoptotic signals, induced by chemotherapeutic drugs against feline tumors have not been fully characterized. Therefore, we have evaluated the expression of Bcl-2 and Bcl-xL in FT-1 upon in vitro treatment with these drugs. In the present study, full length of feline Bcl-xL gene was sequenced, and the expressions of Bcl-2 and Bcl-xL mRNAs in feline lymphoma cell line (FT-1) cultured with doxorubicin, prednisolone or vincristine were investigated. Feline Bcl-xL clone was 1163 base pairs in length and encoded 233 amino acids. The predicted amino acid sequence was 99.1%, 98.7%, 96.1%, 97.4%, 97.0% and 97.9% homologous to predicted Bcl-xL of dog, human, mouse, pig, rat and sheep, respectively. The levels of Bcl-2 transcripts at 24h incubation in FT-1 stimulated with doxorubicin (0.3mug/ml), prednisolone (0.2mug/ml) and vincristine (5ng/ml) were increased to about 41.0-, 62.0- and 11.1-fold to those in non-stimulated FT-1, respectively. On the other hand, the level of Bcl-xL transcripts at 24h incubation in FT-1 stimulated by doxorubicin and prednisolone were significantly increased about 4.2- and 5.8-folds to the controls and inducible level of Bcl-xL by vincristine was decreased about 0.35-folds.

A novel Bcl-x splice product, Bcl-xAK, triggers apoptosis in human melanoma cells without BH3 domain

Pro- and antiapoptotic proteins of the large Bcl-2 family are critical regulators of apoptosis via the mitochondrial pathway. Whereas antiapoptotic proteins of the family share all four Bcl-2 homology domains (BH1-BH4), proapoptotic members may lack some of these domains, but all so far described proapoptotic Bcl-2 proteins enclose BH3. The bcl-x gene gives rise to several alternative splice products resulting in proteins with distinct functions as the antiapoptotic Bcl-xL and proapoptotic Bcl-xS. Here, we describe a novel Bcl-x splice product of 138 amino acids termed Bcl-xAK (Atypical Killer), which encloses the Bcl-2 homology domains BH2 and BH4 as well as the transmembrane domain, but lacks BH1 and BH3. Weak endogenous expression of Bcl-xAK was seen in melanoma and other tumor cells. Interestingly, its overexpression by applying a tetracycline-inducible expression system resulted in significant induction of apoptosis in melanoma cells, which occurred in synergism with drug-induced apoptosis. After exogenous overexpression, Bcl-xAK was localized both in mitochondrial and in cytosolic cell fractions. By these findings, a completely new class of Bcl-2-related proteins is introduced, which promotes apoptosis independently from the BH3 domain and implies additional, new mechanisms for apoptosis regulation in melanoma cells.

Apoptotic markers for primary brain tumor prognosis

Molecular studies of brain tumors have provided insights into pathogenesis, yet it is unclear how important these markers are in predicting clinical outcome and response to treatment. Quantitation of apoptosis by various techniques and the expression of several apoptotic markers have been studied in brain tumors, seeking to refine the information gained from established prognostic variables, which traditionally dictate therapeutic approaches. In the present review we discuss the role of the most extensively examined molecules involved in the apoptotic procedure, such as bcl-2, bax, fas/fasL, survivin and p53, as well as the incidence of baseline apoptosis in various brain tumors, in relation to prognosis. Summarizing current evidence, increased apoptosis and p53 genetic alterations have been advanced as adverse prognosticators in various types of central nervous system neoplasms, while bcl-2 expression appears to be deprived of any predictive value in primary brain tumors. The prognostic significance of the remaining apoptosis-related molecules remains controversial or too limited to draw any firm conclusions. The lack of unanimity of results mostly based on single-center retrospective studies underscores the necessity for large prospective randomized clinical trials, to elucidate the role of these molecular markers as determinants of clinical decision-making and as potential correlates of a pathobiologically tailored and individualized treatment strategy.

Downregulation of Bax mRNA expression and protein stability by the E6 protein of human papillomavirus 16

Previous studies have shown that human papillomavirus (HPV) 16 E6 inhibits apoptosis induced during terminal differentiation of primary human keratinocytes (PHKs) triggered by serum and calcium. E6 inhibition of apoptosis was accompanied with prolonged expression of Bcl-2 and reduced elevation of Bax levels. In the present study, the effect of E6 on Bax mRNA expression and protein stability was investigated. These studies indicate that stable E6 expression in differentiating keratinocytes reduced the steady-state levels of Bax mRNA and shortened the half-life of Bax protein. These results were confirmed in transiently transfected 293T cells where E6 degraded Bax in a dose-dependent manner. Bax degradation was also exhibited in Saos-2 cells that lack p53, indicating its p53 independence. E6 did not form complexes with Bax and did not induce Bax degradation in vitro under experimental conditions where p53 was degraded. Finally, E6 aa 120–132 were shown to be necessary for Bax destabilization and, more importantly, for abrogating the ability of Bax to induce cellular apoptosis, highlighting the functional consequences of the E6-induced alterations in Bax expression.

G125A single-nucleotide polymorphism in the human BAX promoter affects gene expression

Earlier we had reported a guanine to adenosine substitution at position 125 (G125A) in the BAX promoter, and its association with higher stage of the disease and failure to achieve complete response to treatment in chronic lymphocytic leukemia (CLL) patients. The aim of this study was to test the hypothesis that G125A leads to a reduction in the transcription of the BAX gene and that this is a direct cause of altered BAX mRNA and protein expression. In lymphocytes of CLL patients, BAX mRNA expression was determined by RNase protection assay and Bax protein was detected by immunoblotting. The presence of G125A in the BAX promoter was associated with lower BAX mRNA (P=0.004) and protein (P=0.024) levels. In transient expression assays using wild-type and mutant BAX promoter sequences linked to Luciferase as a reporter, the G125A polymorphism reduced expression of the BAX promoter by 2.6-fold. These studies suggest a mechanism for the biological effect of the G125A.

Changes in gene expression induced by phosphorothioate oligodeoxynucleotides (including G3139) in PC3 prostate carcinoma cells are recapitulated at least in part by treatment with interferon-beta and -gamma

PURPOSE

G3139 is an antisense bcl-2 phosphorothioate oligodeoxyribonucleotide that is currently being evaluated in Phase III clinical trials in several human cancers. The aim of the present work was to further identify the apparent non-bcl-2-dependent mechanism of this action of this compound in PC3 prostate cancer cells.

EXPERIMENTAL DESIGN

We performed Affymetrix U95A oligonucleotide microarray studies on mRNA isolated from cells treated with G3139 and related oligonucleotides.

RESULTS

Hierarchical clustering revealed the presence of a set of genes of which the expression was elevated on both 1 and 3 days after oligonucleotide treatment. Significantly, the persistence of expression of the up-regulation of these genes, many of which are members of the IFN cascade, was greater for G3139 than for any other oligomer evaluated. Furthermore, many of the genes with the greatest up-regulation of expression are also those of which the expression is up-regulated after treatment of cells with IFNs. Treatment of PC3 cells with either IFN-beta or -gamma recapitulated some of the aspects of the molecular and phenotypic changes observed after treatment with a G3139/Lipofectin complex. These include down-regulation of bcl-2 protein expression itself, down-regulation of protein kinase C alpha protein expression (but not that of other protein kinase C isoforms), alteration in p21/Waf1/Cip1 protein expression, up-regulation of MHC-I cell surface expression, and profound suppression of cell growth in the absence of a notable increase in cellular apoptosis. However, G3139 (when complexed with Lipofectin) did not induce the up-regulation of expression of either type I or type II IFNs, nor could IFNs be found in conditioned media from treated cells.

CONCLUSIONS

Oligonucleotide microarray experiments demonstrated that G3139 could induce elements of the IFN cascade in PC3 cells in vitro. In addition, the cellular phenotype obtained after treatment with exogenous IFN could, at least in part, recapitulate that obtained after G3139 treatment. Nevertheless, the oligonucleotide microarray experiments we performed also demonstrated that there are extremely large qualitative and quantitative differences between the two treatments.

Bax regulates c-Myc-induced mammary tumour apoptosis but not proliferation in MMTV-c-myc transgenic mice

The expression of the proto-oncogene c-myc is frequently deregulated, via multiple mechanisms, in human breast cancers. Deregulated expression of c-myc contributes to mammary epithelial cell transformation and is causally involved in mammary tumorigenesis in MMTV-c-myc transgenic mice. c-Myc is known to promote cellular proliferation, apoptosis, genomic instability and tumorigenesis in several distinct tissues, both in vivo and in vitro. Expression of the proapoptotic regulatory gene bax is reduced or absent in human breast cancers, and c-Myc has been shown to regulate the expression of Bax, as well as cooperate with Bax in controlling apoptosis in a fibroblast model. Additionally, loss of bax reduces c-Myc-induced apoptosis in lymphoid cells and increases c-Myc-mediated lymphomagenesis in vivo. In order to assess whether loss of bax could influence c-Myc-induced apoptosis and tumorigenesis in the mammary gland in vivo, we generated MMTV-c-myc transgenic mice in which neither, one, or both wild-type alleles of bax were eliminated. Haploid loss of bax in MMTV-c-myc transgenic mice resulted in significantly reduced mammary tumour apoptosis. As anticipated for an apoptosis-regulatory gene, loss of the wild-type bax alleles did not significantly alter cellular proliferation in either mammary adenocarcinomas or dysplastic mammary tissues. However, in contrast to c-Myc-mediated lymphomagenesis, loss of one or both alleles of bax in MMTV-c-myc transgenic mice did not significantly enhance mammary tumorigenesis, despite evidence that haploid loss of bax might modestly increase mammary tumour multiplicity. Our results demonstrate that Bax contributes significantly to c-Myc-induced apoptosis in mammary tumours. In addition, they suggest that in contrast to c-Myc-induced lymphomagenesis, mammary tumorigenesis induced by deregulated c-myc expression requires some amount of Bax expression.

Is drug-induced toxicity a good predictor of response to neo-adjuvant chemotherapy in patients with breast cancer?--a prospective clinical study

BACKGROUND

Neo-adjuvant chemotherapy is an integral part of multi-modality approach in the management of locally advanced breast cancer and it is vital to predict the response in order to tailor the regime for a patient. The common final pathway in the tumor cell death is believed to be apoptosis or programmed cell death and chemotherapeutic drugs like other DNA-damaging agents act on rapidly multiplying cells including both the tumor and the normal cells by following the same common final pathway. This could account for both the toxic effects and the response. Absence or decreased apoptosis has been found to be associated with chemo resistance. The change in expression of apoptotic markers (Bcl-2 and Bax proteins) brought about by various chemotherapeutic regimens is being used to identify drug resistance in the tumor cells. A prospective clinical study was conducted to assess whether chemotherapy induced toxic effects could serve as reliable predictors of apoptosis or response to neo-adjuvant chemotherapy in patients with locally advanced breast cancer.

METHODS

50 cases of locally advanced breast cancer after complete routine and metastatic work up were subjected to trucut biopsy and the tissue evaluated immunohistochemically for apoptotic markers (bcl-2/bax ratio). Three cycles of Neoadjuvant Chemotherapy using FAC regime (5-fluorouracil, adriamycin, cyclophosphamide) were given at three weekly intervals and patients assessed for clinical response as well as toxicity after each cycle. Modified radical mastectomy was performed in all patients three weeks after the last cycle and the specimen were re-evaluated for any change in the bcl-2/bax ratio. The clinical response, immunohistochemical response and the drug-induced toxicity were correlated and compared. Descriptive studies were performed with SPSS version 10 and the significance of response was assessed using paired t-test. Significance of correlation between various variables was assessed using chi-square test and coefficient of correlation calculated by Pearson correlation coefficient.

RESULTS

There was a statistically significant correlation observed between clinical, immunohistochemical response (bcl-2/bax ratio) and the drug-induced toxicity.

CONCLUSION

Responders also had significant toxicity while non-responders did not show significant toxicity following neoadjuvant chemotherapy. The chemotherapy-induced toxicity was observed to be a cost effective and reliable predictor of response to neo-adjuvant chemotherapy.

Death receptors in chemotherapy and cancer

Apoptosis, the cell's intrinsic death program, is a key regulator of tissue homeostasis. An imbalance between cell death and proliferation may result in tumor formation. Also, killing of cancer cells by cytotoxic therapies such as chemotherapy, gamma-irradiation or ligation of death receptors is predominantly mediated by triggering apoptosis in target cells. In addition to the intrinsic mitochondrial pathway, elements of death receptor signaling pathways have been implied to contribute to the efficacy of cancer therapy. Failure to undergo apoptosis in response to anticancer therapy may lead to resistance. Also, deregulated expression of death receptor pathway molecules may contribute to tumorigenesis and tumor escape from endogenous growth control. Understanding the molecular events that regulate apoptosis induced by anticancer therapy and how cancer cells evade apoptosis may provide new opportunities for pathway-based rational therapy and for drug development.

Inhibition of rat mammary gland carcinogenesis by simultaneous targeting of cyclooxygenase-2 and peroxisome proliferator-activated receptor gamma

We examined the effect of celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, and N-(9-fluorenyl-methyloxycarbonyl)-L-leucine (F-L-Leu), a peroxisome proliferator-activated receptor gamma (PPAR gamma) agonist, separately and combined, on the development of methylnitrosourea (MNU)-induced rat mammary gland carcinogenesis. Celecoxib and F-L-Leu significantly reduced tumor incidence and multiplicity (P < 0.05). Combining both agents exerted higher (synergistic) cancer inhibition than separate treatments (P < 0.05). The effects of the test drugs on COX-2 and PPAR gamma expression and on the synthesis of prostaglandin E(2) (PGE(2)) and 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) were examined in rat mammary normal (MNU-untreated), uninvolved, and tumor (MNU-treated) tissues. Celecoxib and F-L-Leu, separately, inhibited COX-2 and up-regulated PPAR gamma expression. These effects were paralleled by inhibition of PGE(2) synthesis and up-regulation of 15d-PGJ(2). Combined treatment resulted in higher alterations in COX-2 and PPAR gamma transcripts and PG synthesis compared with separate administrations. The effect of the test agents on Bcl(2), BAX, and protein kinase C alpha expression levels were examined in the rat mammary gland and the pro-(BAX:Bcl(2)) and anti-[PKC alpha*(Bcl(2)/BAX)] apoptotic ratios were evaluated. Each drug increased the proapoptotic ratio by 2- to 7-fold and reduced the antiapoptotic ratio by 2- to >8-fold in all tissues. Combined treatment, however, resulted in >9- to 14-fold up-regulation in the proapoptotic processes and 15- to >30-fold down-regulation in the antiapoptotic ones. Analyses were also carried out on the drug-induced modulation of cell cycle regulators and proliferation markers (cyclin-dependent kinase 1 and proliferating cell nuclear antigen). F-L-Leu and celecoxib each reduced the cyclin-dependent kinase 1 and proliferating cell nuclear antigen expression in the tumor. Higher down-regulation was attained in all tissues by combined treatment where cyclin-dependent kinase 1 and proliferating cell nuclear antigen almost retained the expression levels observed in the normal glands. In conclusion, simultaneous targeting of COX-2 and PPAR gamma may inhibit mammary cancer development more effectively than targeting each molecule alone. COX-2 inhibitors and PPAR gamma agonists coordinately mediate their anticancer effect via both COX-dependent (inhibition of COX-2, activation of PPAR gamma, and modulation PG synthesis) and COX-independent (induction of proapoptotic factors and inhibition of cell proliferation) pathways.

PC cell-derived growth factor mediates tamoxifen resistance and promotes tumor growth of human breast cancer cells

PC cell-derived growth factor, also known as progranulin, is an M(r) 88,000 growth factor (referred as PCDGF/GP88) overexpressed in human breast cancer. Antisense inhibition of PCDGF/GP88 expression in MDA-MB-468 cells inhibited tumor formation in nude mice. In estrogen receptor-positive cells, PCDGF/GP88 was expressed in response to estradiol and shown to mediate its mitogenic effect. Pathologic studies indicated that PCDGF/GP88 was expressed in 80% of invasive ductal carcinomas in correlation with parameters of poor prognosis. In the present article, the relationship between PCDGF/GP88 expression and tamoxifen resistance was examined in MCF-7 cells. PCDGF/GP88 overexpression rendered MCF-7 cells able to proliferate in the absence of estrogen and in the presence of tamoxifen. The PCDGF/GP88-overexpressing cells formed tumors in ovariectomized nude mice in the absence of estradiol and in its presence, in contrast to MCF-7 cells. Tumor growth of the overexpressing cells was increased significantly when the mice were treated with tamoxifen. PCDGF/GP88 blocked tamoxifen-induced apoptosis by preventing down-regulation of bcl-2 expression and poly(ADP-ribose) polymerase cleavage. In addition, PCDGF/GP88-overexpressing cells presented higher level of the angiogenic factors vascular endothelial growth factor and angiopoietin-1 than MCF-7 control cells. Tamoxifen treatment additionally increased the level of vascular endothelial growth factor. These studies suggest that PCDGF/GP88 plays a critical role in breast cancer tumorigenesis and in the transition to estrogen independence and tamoxifen resistance, a hallmark of poor prognosis. On the basis of the in vivo studies, it is postulated that tamoxifen treatment of patients with estrogen receptor-positive breast tumors overexpressing PCDGF/GP88 could have adverse clinical consequences.

Expression patterns of biologic markers in small breast cancers and preneoplastic breast lesions

When does proliferating breast epithelium turn malignant? Single parameter analyses have not answered this question. We have tried to answer this through an analysis of immunohistochemical staining patterns in the following morphologically defined breast lesions: atypical ductal hyperplasia (ADH, 23 cases), papilloma (12 cases), ductal cancer in situ (DCIS, 28 cases), and mammographically detected small primary cancers (34 cases). The seven antibodies used were c-neu, bcl-2, p53, p21, CD44, MIB 1, and FAS. Staining patterns were compared within groups and between groups of lesions. Interesting differences in staining patterns were seen between invasive ductal cancer and invasive lobular cancer: invasive lobular cancer was less p53-positive and more CD44-positive than invasive ductal cancer. We found no common pattern in the different proliferating epithelia to show when they become malignant.

Identification of a novel subpopulation of human cord blood CD34-CD133-CD7-CD45+lineage- cells capable of lymphoid/NK cell differentiation after in vitro exposure to IL-15

The hemopoietic stem cell (HSC) compartment encompasses cell subsets with heterogeneous proliferative and developmental potential. Numerous CD34(-) cell subsets that might reside at an earlier stage of differentiation than CD34(+) HSCs have been described and characterized within human umbilical cord blood (UCB). We identified a novel subpopulation of CD34(-)CD133(-)CD7(-)CD45(dim)lineage (lin)(-) HSCs contained within human UCB that were endowed with low but measurable extended long-term culture-initiating cell activity. Exposure of CD34(-)CD133(-)CD7(-)CD45(dim)lin(-) HSCs to stem cell factor preserved cell viability and was associated with the following: 1) concordant expression of the stem cell-associated Ags CD34 and CD133, 2) generation of CFU-granulocyte-macrophage, burst-forming unit erythroid, and megakaryocytic aggregates, 3) significant extended long-term culture-initiating cell activity, and 4) up-regulation of mRNA signals for myeloperoxidase. At variance with CD34(+)lin(-) cells, CD34(-)CD133(-)CD7(-)CD45(dim)lin(-) HSCs maintained with IL-15, but not with IL-2 or IL-7, proliferated vigorously and differentiated into a homogeneous population of CD7(+)CD45(bright)CD25(+)CD44(+) lymphoid progenitors with high expression of the T cell-associated transcription factor GATA-3. Although they harbored nonclonally rearranged TCRgamma genes, IL-15-primed CD34(-)CD133(-)CD7(-)CD45(dim)lin(-) HSCs failed to achieve full maturation, as manifested in their CD3(-)TCRalphabeta(-)gammadelta(-) phenotype. Conversely, culture on stromal cells supplemented with IL-15 was associated with the acquisition of phenotypic and functional features of NK cells. Collectively, CD34(-)CD133(-)CD7(-)CD45(dim)lin(-) HSCs from human UCB displayed an exquisite sensitivity to IL-15 and differentiated into lymphoid/NK cells. Whether the transplantation of CD34(-)lin(-) HSCs possessing T/NK cell differentiation potential may impact on immunological reconstitution and control of minimal residual disease after HSC transplantation for autoimmune or malignant diseases remains to be determined.

Alteration of apoptotic regulatory molecules expression during carcinogenesis and tumor progression of renal cell carcinoma

BACKGROUND

In order to characterize the alteration of apoptotic regulatory molecule expressions during carcinogenesis and tumor progression of renal cell carcinoma (RCC), we compared the expressions between tumor and normal tissues, and evaluated the relationships between expressions in tumors with pathological and clinical characteristics.

METHODS

Reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) allowed the determination of Fas, Fas ligand (FasL), and bcl-2 mRNA expressions in surgically resected tissues of 40 cases of RCC.

RESULTS

In comparing the mRNA expression incidence between tumor and normal tissues, RT-PCR analysis demonstrated that the Fas and bcl-2 incidence in tumors was significantly lower than that in normal tissues. An IHC analysis was supportive of the RT-PCR results that higher immunoreactivity was recognized in mRNA positive cases than in negative cases. With regard to relationships with pathological and clinical characteristics, FasL mRNA expression was recognized significantly more frequently in pT3a tumors than in pT1 tumors, and also more frequently in G2 tumors than in G1 tumors. A similar result was obtained by IHC analysis. Five patients died of cancer. Four of these patients had tumors which showed positive mRNA expression and a strong immunoreactivity of FasL.

CONCLUSION

It is suggested that the alteration of the down-regulated expression of Fas and bcl-2 might contribute to the carcinogenesis of RCC. It is also suggested that the alteration of up-regulated expression of FasL in tumors, which establishes the immune evasion mechanism in some malignancies, might be characterized during the tumor progression of RCC.

Angiogenesis, p53, and bcl-2 expression as prognostic indicators in endometrial cancer: comparison with traditional clinicopathologic variables

We investigated the relation of expression of tumor-suppressor gene product p53, apoptosis-regulator gene product bcl-2, and CD34 (as a measure of microvessel density [MVD]) with traditional clinicopathologic prognostic variables in endometrial carcinoma (histologic type, grade, depth of myometrial invasion, angiolymphatic invasion, lymph node involvement). In specimens from 63 patients with endometrial carcinoma, the mean MVD (64.38+/-28.71 microvessels per 200x field) was not related to any clinicopathologic variables. Nuclear p53 expression was detected in 15 (23.8%) patients and was higher in nonendometrioid carcinomas (p<0.05) and in tumors with increasing histologic grade (p<0.001). Cytoplasmic bcl-2 staining was seen in 79.3% of the tumors. There was a negative correlation between bcl-2 expression and histologic type and tumor grade (p<0.05). In survival analysis, patient age, FIGO stage, high expression of p53, low expression of bcl-2, and high and intermediate MVD values were found to be the most significant prognostic indicators of survival (p<0.05). In multivariate regression analysis, FIGO stage and low bcl-2 expression were found to be the only independent indicators of prognosis (p<0.05).