Search

The surgical management of breast cancer has changed considerably since the use of the Halstedian radical mastectomy early in the 20th century. Over the last 50 years, several landmark clinical trials from the USA and Europe have resulted in a paradigm shift in the management of breast cancer toward less radical forms of surgery with the combined use of multi-modality treatments including systemic chemotherapy, endocrine therapy, and radiotherapy. Advances in such research have established a new worldwide standard of care for breast cancer surgical management and treatment, which has become more patient centric and which places a higher emphasis on cosmesis and improved patient quality of life. In this chapter, we review the landmark clinical trials that have influenced surgical management for non-invasive and invasive breast cancer and that serve to guide current clinical practices to date.

Interactions between the dual Bcr/Abl and aurora kinase inhibitor MK-0457 and the histone deacetylase inhibitor vorinostat were examined in Bcr/Abl+ leukemia cells, including those resistant to imatinib mesylate (IM), particularly those with the T315I mutation. Coadministration of vorinostat dramatically increased MK-0457 lethality in K562 and LAMA84 cells. Notably, the MK-0457/vorinostat regimen was highly active against primary CD34+ chronic myelogenous leukemia (CML) cells and Ba/F3 cells bearing various Bcr/Abl mutations (ie, T315I, E255K, and M351T), as well as IM-resistant K562 cells exhibiting Bcr/Abl-independent, Lyn-dependent resistance. These events were associated with inactivation and down-regulation of wild-type (wt) and mutated Bcr/Abl (particularly T315I). Moreover, treatment with MK-0457 resulted in accumulation of cells with 4N or more DNA content, whereas coadministration of vorinostat markedly enhanced aurora kinase inhibition by MK-0457, and preferentially killed polyploid cells. Furthermore, vorinostat also interacted with a selective inhibitor of aurora kinase A and B to potentiate apoptosis without modifying Bcr/Abl activity. Finally, vorinostat markedly induced Bim expression, while blockade of Bim induction by siRNA dramatically diminished the capacity of this agent to potentiate MK-0457 lethality. Together, these findings indicate that vorinostat strikingly increases MK-0457 activity against IM-sensitive and -resistant CML cells through inactivation of Bcr/Abl and aurora kinases, as well as by induction of Bim.

Cancer/testis (CT) genes are normally expressed in germ cells only, yet are reactivated and expressed in some tumors. Of the approximately 40 CT genes or gene families identified to date, 20 are on the X chromosome and are present as multigene families, many with highly conserved members. This indicates that novel CT gene families may be identified by detecting duplicated expressed genes on chromosome X. By searching for transcript clusters that map to multiple locations on the chromosome, followed by in silico analysis of their gene expression profiles, we identified five novel gene families with testis-specific expression and >98% sequence identity among family members. The expression of these genes in normal tissues and various tumor cell lines and specimens was evaluated by qualitative and quantitative RT-PCR, and a novel CT gene family with at least 13 copies was identified on Xq24, designated as CT47. mRNA expression of CT47 was found mainly in the testes, with weak expression in the placenta. Brain tissue was the only positive somatic tissue tested, with an estimated CT47 transcript level 0.09% of that found in testis. Among the tumor specimens tested, CT47 expression was found in approximately 15% of lung cancer and esophageal cancer specimens, but not in colorectal cancer or breast cancer. The putative CT47 protein consists of 288 amino acid residues, with a C-terminus rich in alanine and glutamic acid. The only species other than human in which a gene homologous to CT47 has been detected is the chimpanzee, with the predicted protein showing approximately 80% identity in its carboxy terminal region.

The role of the Ras/MEK/ERK pathway was examined in relation to DNA damage in human multiple myeloma (MM) cells exposed to Chk1 inhibitors in vitro and in vivo. Exposure of various MM cells to marginally toxic concentrations of the Chk1 inhibitors UCN-01 or Chk1i modestly induced DNA damage, accompanied by Ras and ERK1/2 activation. Interruption of these events by pharmacologic (eg, the farnesyltransferase inhibitor R115777 or the MEK1/2 inhibitor PD184352) or genetic (eg, transfection with dominant-negative Ras or MEK1 shRNA) means induced pronounced DNA damage, reflected by increased γH2A.X expression/foci formation and by comet assay. Increased DNA damage preceded extensive apoptosis. Notably, similar phenomena were observed in primary CD138+ MM cells. Enforced MEK1/2 activation by B-Raf transfection prevented R115777 but not PD184352 from inactivating ERK1/2 and promoting Chk1 inhibitor–induced γH2A.X expression. Finally, coadministration of R115777 diminished UCN-01–mediated ERK1/2 activation and markedly potentiated γH2A.X expression in a MM xenograft model, associated with a striking increase in tumor cell apoptosis and growth suppression. Such findings suggest that Ras/MEK/ERK activation opposes whereas its inhibition dramatically promotes Chk1 antagonist–mediated DNA damage. Together, these findings identify a novel mechanism by which agents targeting the Ras/MEK/ERK pathway potentiate Chk1 inhibitor lethality in MM.

Cancer/testis (CT) genes are normally expressed in germ cells only, yet are reactivated and expressed in some tumors. Of the approximately 40 CT genes or gene families identified to date, 20 are on the X chromosome and are present as multigene families, many with highly conserved members. This indicates that novel CT gene families may be identified by detecting duplicated expressed genes on chromosome X. By searching for transcript clusters that map to multiple locations on the chromosome, followed by in silico analysis of their gene expression profiles, we identified five novel gene families with testis-specific expression and98% sequence identity among family members. The expression of these genes in normal tissues and various tumor cell lines and specimens was evaluated by qualitative and quantitative RT-PCR, and a novel CT gene family with at least 13 copies was identified on Xq24, designated as CT47. mRNA expression of CT47 was found mainly in the testes, with weak expression in the placenta. Brain tissue was the only positive somatic tissue tested, with an estimated CT47 transcript level 0.09% of that found in testis. Among the tumor specimens tested, CT47 expression was found in approximately 15% of lung cancer and esophageal cancer specimens, but not in colorectal cancer or breast cancer. The putative CT47 protein consists of 288 amino acid residues, with a C-terminus rich in alanine and glutamic acid. The only species other than human in which a gene homologous to CT47 has been detected is the chimpanzee, with the predicted protein showing approximately 80% identity in its carboxy terminal region.

Massively parallel signature sequencing (MPSS) generates millions of short sequence tags corresponding to transcripts from a single RNA preparation. Most MPSS tags can be unambiguously assigned to genes, thereby generating a comprehensive expression profile of the tissue of origin. From the comparison of MPSS data from 32 normal human tissues, we identified 1,056 genes that are predominantly expressed in the testis. Further evaluation by using MPSS tags from cancer cell lines and EST data from a wide variety of tumors identified 202 of these genes as candidates for encoding cancer/testis (CT) antigens. Of these genes, the expression in normal tissues was assessed by RT-PCR in a subset of 166 intron-containing genes, and those with confirmed testis-predominant expression were further evaluated for their expression in 21 cancer cell lines. Thus, 20 CT or CT-like genes were identified, with several exhibiting expression in five or more of the cancer cell lines examined. One of these genes is a member of a CT gene family that we designated as CT45. The CT45 family comprises six highly similar (>98% cDNA identity) genes that are clustered in tandem within a 125-kb region on Xq26.3. CT45 was found to be frequently expressed in both cancer cell lines and lung cancer specimens. Thus, MPSS analysis has resulted in a significant extension of our knowledge of CT antigens, leading to the discovery of a distinctive X-linked CT-antigen gene family.

Transcripts with ESTs derived exclusively or predominantly from testis, and not from other normal tissues, are likely to be products of genes with testis-restricted expression, and are thus potential cancer/testis (CT) antigen genes. A list of 371 genes with such characteristics was compiled by analyzing publicly available EST databases. RT-PCR analysis of normal and tumor tissues was performed to validate an initial selection of 20 of these genes. Several new CT and CT-like genes were identified. One of these, CT46/HORMAD1, is expressed strongly in testis and weakly in placenta; the highest level of expression in other tissues is1% of testicular expression. The CT46/HORMAD1 gene was expressed in 31% (34/109) of the carcinomas examined, with 11% (12/109) showing expression levels10% of the testicular level of expression. CT46/HORMAD1 is a single-copy gene on chromosome 1q21.3, encoding a putative protein of 394 aa. Conserved protein domain analysis identified a HORMA domain involved in chromatin binding. The CT46/HORMAD1 protein was found to be homologous to the prototype HORMA domain-containing protein, Hop1, a yeast meiosis-specific protein, as well as to asy1, a meiotic synaptic mutant protein in Arabidopsis thaliana.

Background Ovarian cancer constitutes nearly 4% of all cancers among women and is the leading cause of death from gynecologic malignancies in the Western world. Standard first line adjuvant chemotherapy treatments include Paclitaxel (Taxol) and platinum-based agents. Taxol, epothilone B (EpoB) and discodermolide belong to a family of anti-neoplastic agents that specifically interferes with microtubules and arrests cells in the G2/M phase of the cell cycle. Despite initial success with chemotherapy treatment, many patients relapse due to chemotherapy resistance. In vitro establishment of primary ovarian cancer cells provides a powerful tool for better understanding the mechanisms of ovarian cancer resistance. We describe the generation and characterization of primary ovarian cancer cells derived from ascites fluids of patients with epithelial ovarian cancer. Methods Chemosensitivity of these cell lines to Taxol, EpoB and discodermolide was tested, and cell cycle analysis was compared to that of immortalized ovarian cancer cell lines SKOV3 and Hey. The relationship between drug resistance and αβ-tubulin and p53 status was also investigated. Results All newly generated primary cancer cells were highly sensitive to the drugs. αβ-tubulin mutation was not found in any primary cell lines tested. However, one cell line that harbors p53 mutation at residue 72 (Arg to Pro) exhibits altered cell cycle profile in response to all drug treatments. Immortalized ovarian cancer cells respond differently to EpoB treatment when compared to primary ovarian cancer cells, and p53 polymorphism suggests clinical significance in the anti-tumor response in patients. Conclusions The isolation and characterization of primary ovarian cancer cells from ovarian cancer patients’ specimens contribute to further understanding the nature of drug resistance to microtubule interacting agents (MIAs) currently used in clinical settings.

MK-0457/VX-680 was developed as a pan-aurora kinase inhibitor that induces apoptosis in tumor cells and suppresses tumor growth in vivo. Recently, it was found that MK-0457 is also a potent inhibitor of both wild type and mutated Bcr/Abl kinases, including the T315I mutant which confers resistance to first- (i.e., imatinib mesylate/IM) and second-generation kinase inhibitors (e.g., dasatinib and nilotinib). Moreover, MK-0457 exhibits significant activity in patients with T315I phenotype-refractory CML or Ph-positive ALL. Here we examined interactions between MK-0457 and the histone deacetylase inhibitor (HDACI) vorinostat/SAHA in Bcr/Abl+ leukemia cells, including those resistant to IM through various mechanisms, particularly the T315I mutation. Co-administration of non- or subtoxic concentrations of vorinostat (0.5–2 μM) increased the lethality of MK-0457 (5–100 nM) in a highly synergistic manner in K562 and LAMA84 cells. Similar interactions were observed in primary CD34+ CML cells, whereas the combination largely spared normal bone marrow mononuclear cells. Moreover, the MK-0457/vorinostat regimen markedly induced cell death in IM-resistant K562 cells exhibiting a Bcr/Abl-independent, Lyn-dependent form of resistance, a phenomenon accompanied by Lyn inactivation. Notably, the regimen was highly active against BaF/3 cells bearing various Bcr/Abl point mutations (i.e., T315I, E255K, and M351T) conferring resistance to IM. These events were associated with inactivation and downregulation of wild type and mutated Bcr/Abl (particularly T315I), reduced expression of phospho-CrkL, and vorinostat-mediated interruption of interactions between Bcr/Abl and Hsp90. Moreover, exposure of cells to marginally toxic doses of MK-0457 resulted in accumulation of cells with greater than 4N DNA content, resulting from induction of endoreduplication. Co-administration of vorinostat strikingly enhanced aurora kinase inhibition by MK-0457, reflected by markedly diminished expression of phospho-histone H3 (Ser 10), accompanied by preferential killing of polyploid cells. Interestingly, vorinostat also interacted with a selective inhibitor of aurora kinase A and B, at concentrations that inhibited histone H3 phosphorylation, to potentiate apoptosis in CML cells without modifying expression of phospho-Bcr/Abl or -CrkL. These results suggest that aurora kinase inhibition plays a functional role in synergistic interactions between HDACI and aurora kinase inhibitors. Finally, vorinostat markedly induced expression of the pro-apoptotic BH3-only protein Bim in various CML cell lines, including BaF/3 cells expressing the T315I Bcr/Abl mutation, as well as in primary CML cells. Knockdown of Bim by siRNA significantly protected K562 cells from apoptosis induced by vorinostat but not MK-0457. Furthermore, siRNA-mediated Bim downregulation blocked induction of Bim expression by vorinostat and dramatically diminished the capacity of this agent to potentiate MK-0457 lethality. In addition, blockade of apoptosis by Bim siRNA did not modify downregulation of Bcr/Abl or phospho-histone H3 in cells exposed to the vorinostat/MK-0457 regimen, arguing against the possibility that the latter phenomena are secondary to activation of apoptotic cascade. Together, these findings indicate that vorinostat dramatically increases MK-0457 lethality in IM-sensitive and -resistant CML cells, and suggest that inactivation of Bcr/Abl kinase and aurora kinases, as well as Bim induction by vorinostat, contribute to this phenomenon.