Immunoglobulin genes in their germ-line form are separated DNA subsegments that must be joined by... more Immunoglobulin genes in their germ-line form are separated DNA subsegments that must be joined by means of recombinations during B-cell development. Individual immunoglobulin-gene rearrangements are specific for a given B cell and its progeny. We show that the detection of such gene rearrangements by Southern hybridization provides a sensitive marker for both clonality and B-cell lineage within lymphoid tissues lacking expression of definitive surface phenotypes. We have used these genetic markers in three ways: to establish a diagnosis of lymphoma in a neoplastic disorder of uncertain cell type, to show that some lymphomas that were previously classified as being of T-cell type in fact contain monoclonal B cells, and to detect clonal B-cell populations within lymphomatous tissues of uncertain immunotype and within an atypical lymphofollicular hyperplasia having no other clonal surface markers. These sensitive and unique indicators of clonality located directly at the DNA level are capable of providing insights into the cellular origin, early detection, and natural history of neoplasia.
In most human lymphomas, the chromosome translocation t(14;18) occurs within two breakpoint clust... more In most human lymphomas, the chromosome translocation t(14;18) occurs within two breakpoint clustering regions on chromosome 18, the major one at the 3' untranslated region of the bcl-2 gene and the minor one at 3' of the gene. Analysis of a panel of follicular lymphoma DNAs using probes for the first exon of the bcl-2 gene indicates that DNA rearrangements
Acquisition of mature T cell function and the T cell antigen receptor repertoire occur in the thy... more Acquisition of mature T cell function and the T cell antigen receptor repertoire occur in the thymus. In an effort to delineate the cascade of events leading to T cell matura- tion. we analyzed a series of clonal human precursor T cell neoplasms representing early. middle, and late stages of intrathymic differentiation. Rearrangements of the T cell receptor $ and .'y genes appear concurrently and are preceded by surface expression of the 3A1 (CD7) molecule. Subsequent transcription of the $ gene is coordinated with I NTRATHYMIC T cell differentiation involves a multi- step pathway featuring the rearrangement and transcnip- tional activation ofgenes encoding antigen recognition. Prior to expression of the cell surface membrane T cell antigen receptor (TCR),' genes encoding their a (Ta) and /3 (Ta) subunits must undergo successful variable region rearrange- ment, and their translational products combine with the multichain protein, T3. '�' ' Independent investigations of munine and human immature T cells implicate a hierarchy of events in which transcription of the Tgene occurs early, persists throughout thymocyte development, and precedes the onset of Ta gene transcription.'2'8 Transcripts of a third rearranging gene, T�,'925 have been detected in fetal murine thymocytes, approximately coincident with the appearance of Tfl mRNA, but, except for some munine cytotoxic T cells, remain for only a brief time.'7"8 An ontogenic hierarchy of TCR a, fi, and -y gene rear- rangements analogous to immunoglobulin heavy, K, and A genes26'27 might be suspected, but little information exists in this regard. Both Tand Tgenes rearrange early in thymic development,'8'2' but the ontogeny of Ta gene rearrange- ments has not yet been determined because munine and
In this study, the joining sequences between chromosomes 14 and 18 on the 14q+ chromosomes of a p... more In this study, the joining sequences between chromosomes 14 and 18 on the 14q+ chromosomes of a patient with pre-B-cell leukemia and four patients with follicular lymphoma carrying a t(14;18) chromosome translocation were analyzed. In each case, the involved segment of chromosome 18 has recombined with the immunoglobulin heavy-chain joining segment (JH) on chromosome 14. The sites of the recombination on chromosome 14 are located close to the 5' end of the involved JH segment, where the diversity (D) regions are rearranged with the JH segments in the production of active heavy-chain genes. As extraneous nucleotides (N regions) were observed at joining sites and specific signal-like sequences were detected on chromosome 18 in close proximity to the breakpoints, it is concluded that the t(14;18) chromosome translocation is the result of a mistake during the process of VDJ joining at the pre-B-cell stage of differentiation. The putative recombinase joins separated DNA segments on two different chromosomes instead of joining separated segments on the same chromosome, causing a t(14;18) chromosome translocation in the involved B cells.
A fusion complementary DNA in the T cell line HSB-2 elucidates a provocative mechanism for the di... more A fusion complementary DNA in the T cell line HSB-2 elucidates a provocative mechanism for the disruption of the putative hematopoietic transcription factor SCL. The fusion cDNA results from an interstitial deletion between a previously unknown locus, SIL (SCL interrupting locus), and the 5' untranslated region of SCL. Similar to 1;14 translocations, this deletion disrupts the SCL 5' regulatory region. This event is probably mediated by V-(D)-J recombinase activity, although neither locus is an immunoglobulin or a T cell receptor. Two other T cell lines, CEM and RPMI 8402, have essentially identical deletions. Thus, in lymphocytes, growth-affecting genes other than immune receptors risk rearrangements.
Epstein-Barr virus-immortalized human lymphocytes were used to analyze the transition from the be... more Epstein-Barr virus-immortalized human lymphocytes were used to analyze the transition from the benign hyperproliferative to the malignant transformed state. Treatment with /V-acetoxy-2-acctylaminofluorene. a potent frameshift mutagen, induced conversion of the Epstein-Barr virus immortalized lymphocytes into high-grade "immunoblastic lymphomas" on injection into athymic mice, whereas injection of the untreated, original cells did not. The tumor cells were all of the B-ceII lineage as determined by the presence of surface immunoglobulins and antigens detected by li celi specific antibodies to B, and B* and the absence of the T-cell-specific markers, 3A, and LEU-1. The /V-acctoxy-2-acvtylaminofluorene-induccd tumor lines displayed abnormal diploid to tetraploid karyotypes. The fewest chromosomal rearrangement, excluding tetraploidy, observed in these chemically induced lymphomas involved a deletion in chromosome 6, and additions on both chromosomes 16 and 4. Neither major rearrange ments nor amplifications were found for K-ru.v, H-ras, N-ras, c-myc, Blym, and c-myb in these tumor lines.
We reviewed our experience with six T-cell-rich B-cell lymphomas (TRBL) presenting in skin. Immun... more We reviewed our experience with six T-cell-rich B-cell lymphomas (TRBL) presenting in skin. Immunohistochemical studies were performed on all biopsies. The lymphoid population consisted mainly of CD3 and/or UCHL-1 (CD45RO) positive T cells. 5 to 15% of the lymphoid cells stained for the B-cell marker L26 (CD20). Monoclonality of the B-cell component was demonstrated in all cases, utilizing either light chain restriction (5 cases) or clonal immunoglobulin heavy chain gene rearrangement by polymerase chain reaction (PCR) (2 cases). One case was confirmed to be monoclonal by both techniques. Additionally, no clonal rearrangements of the T-cell receptor gamma gene were observed. There was considerable morphological variety in these cases. In H&E stained sections, the differential diagnosis included pseudolymphoma, peripheral T-cell lymphoma, Hodgkin's disease, Lennert's lymphoma and a MALT lymphoma. A significant component of monoclonal plasma cells was present in 3 of 6 cases, suggesting a possible origin from cutaneous immunocytoma. In fact, one of our cases was a biphasic lymphoma displaying TRBL with a small focus of immunocytoma. We conclude that immunophenotypic analysis is necessary for the diagnosis of TRBL. Pathologists should be aware of this type of cutaneous B-cell lymphoma to avoid misinterpretation as a pseudolymphoma.
Malignant lymphomas have traditionally been classified on solely morphological grounds. With new ... more Malignant lymphomas have traditionally been classified on solely morphological grounds. With new immunological and cytochemical techniques, it has been possible to characterize normal cells of the T-lymphocyte, B-lymphocyte, and monocyte-macrophage system. Application of these methodologies to malignant lymphomas has established their nature as neoplasms of the immune system. Within the B-lymphocyte system it is possible to identify subpopulations responsible for Burkitt's tumour, follicular (nodular) lymphomas, lyn*phocytic lymphomas of intermediate differentiation and well differentiated lymphocytic lymphomas. The T-lymphocyte system includes lymphoblastic lymphomas, mycosis fungoides, and Sezary's syndrome. Large-cell lymphomas are diverse, but the majority are tumours of transformed lymphocytes, usually of the B-lymphocyte system. The precise nature of the neoplastic cells of Hodgkin's disease (i.e., Reed-Sternberg cells and their mononuclear counterparts) has not yet been established. Despite previous suggestions of a B-lymphocyte or T-lymphocyte origin, recent studies with in vitro cultivation have strongly suggested derivation from the monocyte-macrophage system.
Although Hodgkin's disease is highly responsive to treatments that cause apoptosis, it remain... more Although Hodgkin's disease is highly responsive to treatments that cause apoptosis, it remains resistant to the physiological mechanisms intended to cause cell death. Presumably, the Reed-Sternberg cell defies endogenous apoptosis, persists, accumulates, and manifests the malignant disorder seen clinically. The Reed-Sternberg cell expresses several members of the tumor necrosis factor receptor superfamily. This family of receptors is involved in both activation and proliferation of cells, as well as either protection from or initiation of apoptosis in cells expressing these surface proteins. Signals from these receptors affect transcription. We reasoned that the activation state and resistance to apoptosis of Reed-Sternberg cells might be attributable to dysregulation of genes controling these processes. To determine gene expression by Reed-Sternberg cells, we developed a method of micromanipulation, global reverse transcription, and the reverse transcription-polymerase chain re...
Rearrangements of the T-cell antigen receptor genes serve as unique, clonal tumor markers of T-ce... more Rearrangements of the T-cell antigen receptor genes serve as unique, clonal tumor markers of T-cell neoplasms. This approach provides a reliable and sensitive diagnostic tool to document both clonality and lineage of T-cell lymphoproliferative processes.
The cancer/testis antigen (CTA) group of tumor-associated proteins have been reported to be expre... more The cancer/testis antigen (CTA) group of tumor-associated proteins have been reported to be expressed in various cancers and in adult testis but they are essentially not found in any other normal adult nonneoplastic tissues. Prompted by the frequent detection of SSX1 in a previous comprehensive expression profile of the Hodgkin's lymphoma (HL) cell line L428, we analyzed SSX expression by nonnested reverse-transcription polymerase chain reaction (RT-PCR) in 4 HL cell lines (L428, L540, HD-MY-Z, and KM-H2) and 32 tumor samples of HL. The cellular localization of SSX expression in the tumor samples was further analyzed by in situ hybridization (ISH). All 4 HL cell lines were positive by RT-PCR using SSX consensus primers. Using primers specific to individual SSX genes, all 4 cell lines expressed multiple SSX family members. Five tumor samples (15.6%) were positive by RT-PCR using SSX consensus primers and direct sequencing of the RT-PCR products showed that 4 of 5 expressed more t...
The malignant Reed-Sternberg cell of Hodgkin disease is an aberrant B cell that persists in an im... more The malignant Reed-Sternberg cell of Hodgkin disease is an aberrant B cell that persists in an immunolgically mediated inflammatory infiltrate. Despite its nonproductive immunoglobulin genes, the Reed-Sternberg cell avoids the usual apoptotic fate of defective immune cells through an unknown mechanism. A likely candidate is the surface receptor, CD40, consistently expressed by Reed-Sternberg cells, and the first link in the pathway to NF-kappa B activation, the central regulator of cytokine production and apoptosis. CD40 signaling in B lymphocytes coordinates the immune response, including immunoglobulin isotype switch and Fas-mediated apoptosis. CD40-induced NF-kappa B activation is mediated by adapter proteins, the TNF receptor (TNFR)-associated factors (TRAFs), especially TRAFs 2, 3, and 5. Using a Hodgkin cell line, this study demonstrates that CD40 activation of NF-kappa B is mediated by proteolysis of TRAF3. Results further demonstrate that the pathway can be blocked by treatm...
The malignant Reed-Sternberg cell of Hodgkin's disease, first described a century ago, has re... more The malignant Reed-Sternberg cell of Hodgkin's disease, first described a century ago, has resisted in-depth analysis due to its extreme rarity in lymphomatous tissue. To directly study its genome-wide gene expression, approximately 11,000,000 bases (27,518 cDNA sequences) of expressed gene sequence was determined from living single Reed-Sternberg cells, Hodgkin's tissue, and cell lines. This approach increased the number of genes known to be expressed in Hodgkin's disease by 20-fold to 2,666 named genes. The data here indicate that Reed-Sternberg cells from both nodular sclerosing and lymphocyte predominant Hodgkin's disease were derived from an unusual B-cell lineage based on a comparison of their gene expression to approximately 40,000,000 bases (10(5) sequences) of expressed gene sequence from germinal center B cells (GCB) and dendritic cells. The data set of expressed genes, reported here and on the World Wide Web, forms a basis to understand the genes responsib...
Previous studies have shown that bcl-2 overexpression can inhibit apoptosis induced by DNA-damagi... more Previous studies have shown that bcl-2 overexpression can inhibit apoptosis induced by DNA-damaging agents widely used in cancer chemotherapy, including X-irradiation, alkylating agents (hydroperoxycyclophosphamide, etc.), and topoisomerase II inhibitors (etoposide, etc.). However, little is known about the mechanism by which bcl-2 overexpression inhibits apoptosis triggered by these agents. In this study, we examined whether bcl-2 overexpression could have effects on etoposide-induced DNA damage and its repair. For these experiments, we developed CH31 clones (mouse B-cells) stably transfected with human bcl-2 sense plasmids and compared these clones with a parental CH31 clone or CH31 clones with antisense plasmids. Overexpression of bcl-2 protein inhibited etoposide-induced apoptosis and cytotoxicity. However, there was no or little difference in the production and repair of DNA-protein cross-links, DNA single-strand breaks, and double-strand beaks among a parental CH31 clone and C...
Immunoglobulin genes in their germ-line form are separated DNA subsegments that must be joined by... more Immunoglobulin genes in their germ-line form are separated DNA subsegments that must be joined by means of recombinations during B-cell development. Individual immunoglobulin-gene rearrangements are specific for a given B cell and its progeny. We show that the detection of such gene rearrangements by Southern hybridization provides a sensitive marker for both clonality and B-cell lineage within lymphoid tissues lacking expression of definitive surface phenotypes. We have used these genetic markers in three ways: to establish a diagnosis of lymphoma in a neoplastic disorder of uncertain cell type, to show that some lymphomas that were previously classified as being of T-cell type in fact contain monoclonal B cells, and to detect clonal B-cell populations within lymphomatous tissues of uncertain immunotype and within an atypical lymphofollicular hyperplasia having no other clonal surface markers. These sensitive and unique indicators of clonality located directly at the DNA level are capable of providing insights into the cellular origin, early detection, and natural history of neoplasia.
In most human lymphomas, the chromosome translocation t(14;18) occurs within two breakpoint clust... more In most human lymphomas, the chromosome translocation t(14;18) occurs within two breakpoint clustering regions on chromosome 18, the major one at the 3' untranslated region of the bcl-2 gene and the minor one at 3' of the gene. Analysis of a panel of follicular lymphoma DNAs using probes for the first exon of the bcl-2 gene indicates that DNA rearrangements
Acquisition of mature T cell function and the T cell antigen receptor repertoire occur in the thy... more Acquisition of mature T cell function and the T cell antigen receptor repertoire occur in the thymus. In an effort to delineate the cascade of events leading to T cell matura- tion. we analyzed a series of clonal human precursor T cell neoplasms representing early. middle, and late stages of intrathymic differentiation. Rearrangements of the T cell receptor $ and .'y genes appear concurrently and are preceded by surface expression of the 3A1 (CD7) molecule. Subsequent transcription of the $ gene is coordinated with I NTRATHYMIC T cell differentiation involves a multi- step pathway featuring the rearrangement and transcnip- tional activation ofgenes encoding antigen recognition. Prior to expression of the cell surface membrane T cell antigen receptor (TCR),' genes encoding their a (Ta) and /3 (Ta) subunits must undergo successful variable region rearrange- ment, and their translational products combine with the multichain protein, T3. '�' ' Independent investigations of munine and human immature T cells implicate a hierarchy of events in which transcription of the Tgene occurs early, persists throughout thymocyte development, and precedes the onset of Ta gene transcription.'2'8 Transcripts of a third rearranging gene, T�,'925 have been detected in fetal murine thymocytes, approximately coincident with the appearance of Tfl mRNA, but, except for some munine cytotoxic T cells, remain for only a brief time.'7"8 An ontogenic hierarchy of TCR a, fi, and -y gene rear- rangements analogous to immunoglobulin heavy, K, and A genes26'27 might be suspected, but little information exists in this regard. Both Tand Tgenes rearrange early in thymic development,'8'2' but the ontogeny of Ta gene rearrange- ments has not yet been determined because munine and
In this study, the joining sequences between chromosomes 14 and 18 on the 14q+ chromosomes of a p... more In this study, the joining sequences between chromosomes 14 and 18 on the 14q+ chromosomes of a patient with pre-B-cell leukemia and four patients with follicular lymphoma carrying a t(14;18) chromosome translocation were analyzed. In each case, the involved segment of chromosome 18 has recombined with the immunoglobulin heavy-chain joining segment (JH) on chromosome 14. The sites of the recombination on chromosome 14 are located close to the 5' end of the involved JH segment, where the diversity (D) regions are rearranged with the JH segments in the production of active heavy-chain genes. As extraneous nucleotides (N regions) were observed at joining sites and specific signal-like sequences were detected on chromosome 18 in close proximity to the breakpoints, it is concluded that the t(14;18) chromosome translocation is the result of a mistake during the process of VDJ joining at the pre-B-cell stage of differentiation. The putative recombinase joins separated DNA segments on two different chromosomes instead of joining separated segments on the same chromosome, causing a t(14;18) chromosome translocation in the involved B cells.
A fusion complementary DNA in the T cell line HSB-2 elucidates a provocative mechanism for the di... more A fusion complementary DNA in the T cell line HSB-2 elucidates a provocative mechanism for the disruption of the putative hematopoietic transcription factor SCL. The fusion cDNA results from an interstitial deletion between a previously unknown locus, SIL (SCL interrupting locus), and the 5' untranslated region of SCL. Similar to 1;14 translocations, this deletion disrupts the SCL 5' regulatory region. This event is probably mediated by V-(D)-J recombinase activity, although neither locus is an immunoglobulin or a T cell receptor. Two other T cell lines, CEM and RPMI 8402, have essentially identical deletions. Thus, in lymphocytes, growth-affecting genes other than immune receptors risk rearrangements.
Epstein-Barr virus-immortalized human lymphocytes were used to analyze the transition from the be... more Epstein-Barr virus-immortalized human lymphocytes were used to analyze the transition from the benign hyperproliferative to the malignant transformed state. Treatment with /V-acetoxy-2-acctylaminofluorene. a potent frameshift mutagen, induced conversion of the Epstein-Barr virus immortalized lymphocytes into high-grade "immunoblastic lymphomas" on injection into athymic mice, whereas injection of the untreated, original cells did not. The tumor cells were all of the B-ceII lineage as determined by the presence of surface immunoglobulins and antigens detected by li celi specific antibodies to B, and B* and the absence of the T-cell-specific markers, 3A, and LEU-1. The /V-acctoxy-2-acvtylaminofluorene-induccd tumor lines displayed abnormal diploid to tetraploid karyotypes. The fewest chromosomal rearrangement, excluding tetraploidy, observed in these chemically induced lymphomas involved a deletion in chromosome 6, and additions on both chromosomes 16 and 4. Neither major rearrange ments nor amplifications were found for K-ru.v, H-ras, N-ras, c-myc, Blym, and c-myb in these tumor lines.
We reviewed our experience with six T-cell-rich B-cell lymphomas (TRBL) presenting in skin. Immun... more We reviewed our experience with six T-cell-rich B-cell lymphomas (TRBL) presenting in skin. Immunohistochemical studies were performed on all biopsies. The lymphoid population consisted mainly of CD3 and/or UCHL-1 (CD45RO) positive T cells. 5 to 15% of the lymphoid cells stained for the B-cell marker L26 (CD20). Monoclonality of the B-cell component was demonstrated in all cases, utilizing either light chain restriction (5 cases) or clonal immunoglobulin heavy chain gene rearrangement by polymerase chain reaction (PCR) (2 cases). One case was confirmed to be monoclonal by both techniques. Additionally, no clonal rearrangements of the T-cell receptor gamma gene were observed. There was considerable morphological variety in these cases. In H&E stained sections, the differential diagnosis included pseudolymphoma, peripheral T-cell lymphoma, Hodgkin's disease, Lennert's lymphoma and a MALT lymphoma. A significant component of monoclonal plasma cells was present in 3 of 6 cases, suggesting a possible origin from cutaneous immunocytoma. In fact, one of our cases was a biphasic lymphoma displaying TRBL with a small focus of immunocytoma. We conclude that immunophenotypic analysis is necessary for the diagnosis of TRBL. Pathologists should be aware of this type of cutaneous B-cell lymphoma to avoid misinterpretation as a pseudolymphoma.
Malignant lymphomas have traditionally been classified on solely morphological grounds. With new ... more Malignant lymphomas have traditionally been classified on solely morphological grounds. With new immunological and cytochemical techniques, it has been possible to characterize normal cells of the T-lymphocyte, B-lymphocyte, and monocyte-macrophage system. Application of these methodologies to malignant lymphomas has established their nature as neoplasms of the immune system. Within the B-lymphocyte system it is possible to identify subpopulations responsible for Burkitt's tumour, follicular (nodular) lymphomas, lyn*phocytic lymphomas of intermediate differentiation and well differentiated lymphocytic lymphomas. The T-lymphocyte system includes lymphoblastic lymphomas, mycosis fungoides, and Sezary's syndrome. Large-cell lymphomas are diverse, but the majority are tumours of transformed lymphocytes, usually of the B-lymphocyte system. The precise nature of the neoplastic cells of Hodgkin's disease (i.e., Reed-Sternberg cells and their mononuclear counterparts) has not yet been established. Despite previous suggestions of a B-lymphocyte or T-lymphocyte origin, recent studies with in vitro cultivation have strongly suggested derivation from the monocyte-macrophage system.
Although Hodgkin's disease is highly responsive to treatments that cause apoptosis, it remain... more Although Hodgkin's disease is highly responsive to treatments that cause apoptosis, it remains resistant to the physiological mechanisms intended to cause cell death. Presumably, the Reed-Sternberg cell defies endogenous apoptosis, persists, accumulates, and manifests the malignant disorder seen clinically. The Reed-Sternberg cell expresses several members of the tumor necrosis factor receptor superfamily. This family of receptors is involved in both activation and proliferation of cells, as well as either protection from or initiation of apoptosis in cells expressing these surface proteins. Signals from these receptors affect transcription. We reasoned that the activation state and resistance to apoptosis of Reed-Sternberg cells might be attributable to dysregulation of genes controling these processes. To determine gene expression by Reed-Sternberg cells, we developed a method of micromanipulation, global reverse transcription, and the reverse transcription-polymerase chain re...
Rearrangements of the T-cell antigen receptor genes serve as unique, clonal tumor markers of T-ce... more Rearrangements of the T-cell antigen receptor genes serve as unique, clonal tumor markers of T-cell neoplasms. This approach provides a reliable and sensitive diagnostic tool to document both clonality and lineage of T-cell lymphoproliferative processes.
The cancer/testis antigen (CTA) group of tumor-associated proteins have been reported to be expre... more The cancer/testis antigen (CTA) group of tumor-associated proteins have been reported to be expressed in various cancers and in adult testis but they are essentially not found in any other normal adult nonneoplastic tissues. Prompted by the frequent detection of SSX1 in a previous comprehensive expression profile of the Hodgkin's lymphoma (HL) cell line L428, we analyzed SSX expression by nonnested reverse-transcription polymerase chain reaction (RT-PCR) in 4 HL cell lines (L428, L540, HD-MY-Z, and KM-H2) and 32 tumor samples of HL. The cellular localization of SSX expression in the tumor samples was further analyzed by in situ hybridization (ISH). All 4 HL cell lines were positive by RT-PCR using SSX consensus primers. Using primers specific to individual SSX genes, all 4 cell lines expressed multiple SSX family members. Five tumor samples (15.6%) were positive by RT-PCR using SSX consensus primers and direct sequencing of the RT-PCR products showed that 4 of 5 expressed more t...
The malignant Reed-Sternberg cell of Hodgkin disease is an aberrant B cell that persists in an im... more The malignant Reed-Sternberg cell of Hodgkin disease is an aberrant B cell that persists in an immunolgically mediated inflammatory infiltrate. Despite its nonproductive immunoglobulin genes, the Reed-Sternberg cell avoids the usual apoptotic fate of defective immune cells through an unknown mechanism. A likely candidate is the surface receptor, CD40, consistently expressed by Reed-Sternberg cells, and the first link in the pathway to NF-kappa B activation, the central regulator of cytokine production and apoptosis. CD40 signaling in B lymphocytes coordinates the immune response, including immunoglobulin isotype switch and Fas-mediated apoptosis. CD40-induced NF-kappa B activation is mediated by adapter proteins, the TNF receptor (TNFR)-associated factors (TRAFs), especially TRAFs 2, 3, and 5. Using a Hodgkin cell line, this study demonstrates that CD40 activation of NF-kappa B is mediated by proteolysis of TRAF3. Results further demonstrate that the pathway can be blocked by treatm...
The malignant Reed-Sternberg cell of Hodgkin's disease, first described a century ago, has re... more The malignant Reed-Sternberg cell of Hodgkin's disease, first described a century ago, has resisted in-depth analysis due to its extreme rarity in lymphomatous tissue. To directly study its genome-wide gene expression, approximately 11,000,000 bases (27,518 cDNA sequences) of expressed gene sequence was determined from living single Reed-Sternberg cells, Hodgkin's tissue, and cell lines. This approach increased the number of genes known to be expressed in Hodgkin's disease by 20-fold to 2,666 named genes. The data here indicate that Reed-Sternberg cells from both nodular sclerosing and lymphocyte predominant Hodgkin's disease were derived from an unusual B-cell lineage based on a comparison of their gene expression to approximately 40,000,000 bases (10(5) sequences) of expressed gene sequence from germinal center B cells (GCB) and dendritic cells. The data set of expressed genes, reported here and on the World Wide Web, forms a basis to understand the genes responsib...
Previous studies have shown that bcl-2 overexpression can inhibit apoptosis induced by DNA-damagi... more Previous studies have shown that bcl-2 overexpression can inhibit apoptosis induced by DNA-damaging agents widely used in cancer chemotherapy, including X-irradiation, alkylating agents (hydroperoxycyclophosphamide, etc.), and topoisomerase II inhibitors (etoposide, etc.). However, little is known about the mechanism by which bcl-2 overexpression inhibits apoptosis triggered by these agents. In this study, we examined whether bcl-2 overexpression could have effects on etoposide-induced DNA damage and its repair. For these experiments, we developed CH31 clones (mouse B-cells) stably transfected with human bcl-2 sense plasmids and compared these clones with a parental CH31 clone or CH31 clones with antisense plasmids. Overexpression of bcl-2 protein inhibited etoposide-induced apoptosis and cytotoxicity. However, there was no or little difference in the production and repair of DNA-protein cross-links, DNA single-strand breaks, and double-strand beaks among a parental CH31 clone and C...
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