Next-generation sequencing-guided identification and reconstruction of antibody CDR combinations from phage selection outputs

Next-generation sequencing (NGS) technologies have been employed in several phage display platforms for analyzing natural and synthetic antibody sequences and for identifying and reconstructing single-chain variable fragments (scFv) and antigen-binding fragments (Fab) not found by conventional ELISA screens. In this work, we developed an NGS-assisted antibody discovery platform by integrating phage-displayed, single-framework, synthetic Fab libraries. Due to limitations in attainable read and amplicon lengths, NGS analysis of Fab libraries and selection outputs is usually restricted to either V_H or V_L. Since this information alone is not sufficient for high-throughput reconstruction of Fabs, we developed a rapid and simple method for linking and sequencing all diversified CDRs in phage Fab pools. Our method resulted in a reliable and straightforward platform for converting NGS information into Fab clones. We used our NGS-assisted Fab reconstruction method to recover low-frequency rare clones from phage selection outputs. While previous studies chose rare clones for rescue based on their relative frequencies in sequencing outputs, we chose rare clones for reconstruction from less-frequent CDRH3 lengths. In some cases, reconstructed rare clones (frequency ∼0.1%) showed higher affinity and better specificity than high-frequency top clones identified by Sanger sequencing, highlighting the significance of NGS-based approaches in synthetic antibody discovery.

A Novel Cell-Penetrating Antibody Fragment Inhibits the DNA Repair Protein RAD51

DNA damaging chemotherapies are successful in cancer therapy, however, the damage can be reversed by DNA repair mechanisms that may be up-regulated in cancer cells. We hypothesized that inhibiting RAD51, a protein involved in homologous recombination DNA repair, would block DNA repair and restore the effectiveness of DNA damaging chemotherapy. We used phage-display to generate a novel synthetic antibody fragment that bound human RAD51 with high affinity (K_D = 8.1 nM) and inhibited RAD51 ssDNA binding in vitro. As RAD51 is an intracellular target, we created a corresponding intrabody fragment that caused a strong growth inhibitory phenotype on human cells in culture. We then used a novel cell-penetrating peptide "iPTD" fusion to generate a therapeutically relevant antibody fragment that effectively entered living cells and enhanced the cell-killing effect of a DNA alkylating agent. The iPTD may be similarly useful as a cell-penetrating peptide for other antibody fragments and open the door to numerous intracellular targets previously off-limits in living cells.

RecA Inhibitors Potentiate Antibiotic Activity and Block Evolution of Antibiotic Resistance

Antibiotic resistance arises from the maintenance of resistance mutations or genes acquired from the acquisition of adaptive de novo mutations or the transfer of resistance genes. Antibiotic resistance is acquired in response to antibiotic therapy by activating SOS-mediated DNA repair and mutagenesis and horizontal gene transfer pathways. Initiation of the SOS pathway promotes activation of RecA, inactivation of LexA repressor, and induction of SOS genes. Here, we have identified and characterized phthalocyanine tetrasulfonic acid RecA inhibitors that block antibiotic-induced activation of the SOS response. These inhibitors potentiate the activity of bactericidal antibiotics, including members of the quinolone, β-lactam, and aminoglycoside families in both Gram-negative and Gram-positive bacteria. They reduce the ability of bacteria to acquire antibiotic resistance mutations and to transfer mobile genetic elements conferring resistance. This study highlights the advantage of including RecA inhibitors in bactericidal antibiotic therapies and provides a new strategy for prolonging antibiotic shelf life.

Quantitative and multiplexed DNA methylation analysis using long-read single-molecule real-time bisulfite sequencing (SMRT-BS)

Background

DNA methylation has essential roles in transcriptional regulation, imprinting, X chromosome inactivation and other cellular processes, and aberrant CpG methylation is directly involved in the pathogenesis of human imprinting disorders and many cancers. To address the need for a quantitative and highly multiplexed bisulfite sequencing method with long read lengths for targeted CpG methylation analysis, we developed single-molecule real-time bisulfite sequencing (SMRT-BS).

Results

Optimized bisulfite conversion and PCR conditions enabled the amplification of DNA fragments up to ~1.5 kb, and subjecting overlapping 625–1491 bp amplicons to SMRT-BS indicated high reproducibility across all amplicon lengths (r = 0.972) and low standard deviations (≤0.10) between individual CpG sites sequenced in triplicate. Higher variability in CpG methylation quantitation was correlated with reduced sequencing depth, particularly for intermediately methylated regions. SMRT-BS was validated by orthogonal bisulfite-based microarray (r = 0.906; 42 CpG sites) and second generation sequencing (r = 0.933; 174 CpG sites); however, longer SMRT-BS amplicons (>1.0 kb) had reduced, but very acceptable, correlation with both orthogonal methods (r = 0.836-0.897 and r = 0.892-0.927, respectively) compared to amplicons less than ~1.0 kb (r = 0.940-0.951 and r = 0.948-0.963, respectively). Multiplexing utility was assessed by simultaneously subjecting four distinct CpG island amplicons (702–866 bp; 325 CpGs) and 30 hematological malignancy cell lines to SMRT-BS (average depth of 110X), which identified a spectrum of highly quantitative methylation levels across all interrogated CpG sites and cell lines.

Conclusions

SMRT-BS is a novel, accurate and cost-effective targeted CpG methylation method that is amenable to a high degree of multiplexing with minimal clonal PCR artifacts. Increased sequencing depth is necessary when interrogating longer amplicons (>1.0 kb) and the previously reported bisulfite sequencing PCR bias towards unmethylated DNA should be considered when measuring intermediately methylated regions. Coupled with an optimized bisulfite PCR protocol, SMRT-BS is capable of interrogating ~1.5 kb amplicons, which theoretically can cover ~91% of CpG islands in the human genome.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1572-7) contains supplementary material, which is available to authorized users.

Chaetocin antileukemia activity against chronic myelogenous leukemia cells is potentiated by bone marrow stromal factors and overcomes innate imatinib resistance

Chronic myelogenous leukemia (CML) is maintained by a minor population of leukemic stem cells (LSCs) that exhibit innate resistance to tyrosine kinase inhibitors (TKIs) targeting BCR-ABL. Innate resistance can be induced by secreted bone marrow stromal cytokines and growth factors (BMSFs) that protect CML-LSCs from TKIs, resulting in minimal residual disease. Developing strategies to eradicate innate TKI resistance in LSCs is critical for preventing disease relapse. Cancer cells balance reactive oxygen species (ROS) at higher than normal levels, promoting their proliferation and survival, but also making them susceptible to damage by ROS-generating agents. Bcr-Abl increases cellular ROS levels, which can be reduced with TKI inhibitors, whereas, BMSFs increase ROS levels. We hypothesized that BMSF-mediated increases in ROS would trigger ROS damage in TKI-treated CML-LSCs when exposed to chaetocin, a mycotoxin that imposes oxidative stress by inhibiting thioredoxin reductase-1. Here, we showed that chaetocin suppressed viability and colony formation, and induced apoptosis of the murine hematopoietic cell line TonB210 with and without Bcr-Abl expression, and these effects were potentiated by BMSFs. In contrast, imatinib activities in Bcr-Abl-positive TonB210 cells were inhibited by BMSFs. Further, BMSFs did not inhibit imatinib activities when TonB210 cells expressing Bcr-Abl were cotreated with chaetocin. Chaetocin showed similar activities against LSC-enriched CML cell populations isolated from a murine transplant model of CML blast crisis that were phenotypically negative for lineage markers and positive for Sca-1 and c-Kit (CML-LSK). BMSFs and chaetocin increased ROS in CML-LSK cells and addition of BMSFs and chaetocin resulted in higher levels compared with chaetocin or BMSF treatment alone. Pretreatment of CML-LSKs with the antioxidant N-acetylcysteine blocked chaetocin cytotoxicity, even in the presence of BMSFs, demonstrating the importance ROS for chaetocin activities. Chaetocin effects on self-renewal of CML-LSKs were assessed by transplanting CML-LSKs into secondary recipients following ex vivo exposure to chaetocin, in the presence or absence of BMSFs. Disease latency in mice transplanted with CML-LSKs following chaetocin treatment more than doubled compared with untreated CML-LSKs or BMSFs-treated CML-LSKs. Mice transplanted with CML-LSKs following chaetocin treatment in the presence of BMSFs had significantly extended survival time compared with mice transplanted with CML-LSKs treated with chaetocin alone. Our findings indicate that chaetocin activity against CML-LSKs is significantly enhanced in the presence of BMSFs and suggest that chaetocin may be effective as a codrug to complement TKIs in CML treatment by disrupting the innate resistance of CML-LSKs through an ROS dependent mechanism.

Yeast two-hybrid screening of cyclic peptide libraries using a combination of random and PI-deconvolution pooling strategies

We developed a high throughput yeast two-hybrid (Y2H) assay for screening pools of combinatorial cyclic peptide preys against pools of bait proteins. The assay used the PI (pooling with imaginary tags) deconvolution pooling strategy to generate pools of baits and a random pooling strategy to generate pools of cyclic peptide preys. Haploid yeast, expressing pools of baits or preys, were arrayed and mated to each other to generate diploid arrays, where the yeast express both baits and preys. Diploid arrays were scored for activation of the Y2H reporter genes. We used this Y2H pooling strategy, referred to as 'PI-pool-on-random pool', to screen a cyclic peptide library for interactions against Bcr-Abl domains. Seven Bcr-Abl domain baits and LexA control were pooled using the PI deconvolution pooling strategy. The cyclic peptide library was randomly arrayed into pools of ~1000 members. Cyclic peptides were isolated for six of seven Bcr-Abl domain baits. The PI-pool-on-random pooling Y2H assay using high stringency Y2H reporter genes produced no false positives, while missing 20% of real interactions. The high specificity of the PI-pool-on-random pooling Y2H assay eliminates the need to validate interactions. Pooling of baits and preys allows large prey libraries to be screened against multiple baits and takes advantage of PI-deconvolution to determine protein interactions with high sensitivity and specificity. The scalability of this assay allows the peptide preys to be isolated in a high throughput manner against a large number of baits and provides an avenue for generating affinity agents against entire proteomes in the future.

A genetic screen for isolating "lariat" Peptide inhibitors of protein function

Functional genomic analyses provide information that allows hypotheses to be formulated on protein function. These hypotheses, however, need to be validated using reverse genetic approaches, which are difficult to perform on a large scale and in diploid organisms. We developed a genetic screen for isolating "lariat" peptides that function as trans dominant inhibitors of protein function. A lariat consists of a lactone-cyclized peptide with a covalently attached transcription activation domain, which allows combinatorial lariat libraries to be screened for protein interactions using the yeast two-hybrid assay. We isolated lariats against the bacterial repressor protein LexA. LexA regulates bacterial SOS response and LexA mutants that cannot undergo autoproteolysis make bacteria more sensitive to, and inhibit resistance against, cytotoxic reagents. We showed that an anti-LexA lariat blocked LexA autoproteolysis and potentiated the antimicrobial activity of mitomycin C.

Loss of imprinting of the insulin-like growth factor II (IGF2) gene in esophageal normal and adenocarcinoma tissues

To evaluate loss of imprinting (LOI) and expression of the IGF2 gene in matched esophageal normal and adenocarcinoma tissues, we studied a prospective cohort of 77 patients who underwent esophageal resection between 1998 and 2003. IGF2 imprinting status was determined by reverse transcription-polymerase chain reaction (PCR) following ApaI digestion, and quantitative PCR was used to evaluate IGF2 expression, which was correlated with clinicopathologic findings, disease-free and overall survival. In total, 32% (14/44) of informative tissues showed loss of IGF2 imprinting, with a strong correlation between the tumor and normal esophageal epithelia (Kappa = 0.89, P < 0.01). Normal epithelia with LOI had increased expression of IGF2 [median: 2.91, 95% confidence interval (CI): 0.93-5.06] compared with imprinted normal epithelia (median: 1.13, 95% CI: 0.85-1.39) (P = 0.03). In contrast, tumors with LOI had significantly reduced IGF2 expression (median: 1.87, 95% CI: 0.53-5.21) compared with normally imprinted tumors (median: 6.79, 95% CI: 3.39-15.89) (P = 0.016). Patients below the age of 65 years with normally imprinted tumors had significantly reduced 5 year disease-free survival (DFS) (24%) compared with patients whose tumors had LOI for IGF2 (55%) (P = 0.03). Cox regression analysis showed that IGF2 overexpression was associated with significantly reduced disease-free survival (P = 0.04). We conclude that in a subgroup of younger patients, loss of IGF2 imprinting was associated with improved outcome following esophageal resection. Expression of IGF2 in esophageal adenocarcinoma and normal esophageal epithelia depended on imprinting status and tissue type, suggesting novel molecular regulatory mechanisms in esophageal tumorigenesis.

RIZ1 is potential CML tumor suppressor that is down-regulated during disease progression

Background

RIZ1 expression and activity are reduced in many cancers. In AML cell lines and patient material, RIZ1 expression is reduced relative to normal bone marrow. In chronic myelogenous leukemia (CML), blastic transformation is associated with loss of heterozygosity in the region where RIZ1 is located. RIZ1 is a PR domain methyltransferase that methylates histone H3 lysine 9, a modification important for transcriptional repression. In CML blast crisis cell lines RIZ1 represses insulin-like growth factor-1 expression and autocrine signaling. Together these observations suggest that RIZ1 may have a role in the chronic phase to blast crisis transition in CML.

Results

In CML patient material, we observed that RIZ1 expression was decreased during progression from chronic phase to blast crisis. RIZ1 was expressed in mature myeloid and CD34⁺ cells demonstrating that decreased RIZ1 expression in blast crisis is not due to an increased immature cell population. Expression of RIZ1 CML blast crisis cell lines decreased proliferation, increased apoptosis, and enhanced differentiation.

Conclusion

RIZ1 is a candidate tumor suppressor gene whose expression is decreased in blast crisis. Loss of RIZ1 activity results in decreased apoptosis and differentiation and enhanced proliferation. Together these results suggest that loss of RIZ1 expression will lead to an increase in myeloid blast cell population resulting in CML progression.

Fli-1 expression in malignant melanoma

Friend leukemia integration site 1 (Fli-1) has been reported as the first nuclear marker of endothelial differentiation; it is expressed in leukocytes and recently demonstrated in melanomas. Formalin-fixed, paraffin-embedded tissue sections from 97 melanomas including 69 cases of primary and 28 metastatic melanomas were evaluated by immunohistochemistry. Five melanoma cell lines were evaluated by Western blot and immunocytochemistry. Fli-1 expression was observed in all cell lines. Fli-1 expression was higher in metastatic than in primary tumors (r=0.208, p=0.041, Spearman correlation), it positively correlated with Ki-67 expression (r=0.233, p=0.022, Spearman correlation), and the presence of an ulcer in the primary tumor (r=0.267, p=0.030, Spearman correlation). Therefore, the expression of Fli-1 in malignant melanoma appears to be associated with biologically more aggressive tumors.

Cytogenetic abnormality 46,XX,add(21)(q11.2) in a patient with follicular dendritic cell sarcoma

The case of a patient with follicular dendritic cell (FDC) sarcoma with chromosomal aberration add(21)(q11.2) is described. Cytogenetic studies showed the karyotype 46,XX,add(21)(q11.2)[3]/46,XX[17], although the encoded protein involved was not clarified. The abnormal pattern was quite simple, and different from a previous report. The clinical course of the FDC sarcoma in this case has been indolent, as for most FDC sarcoma patients. Although this patient suffered from breast carcinoma 6 years after the onset of FDC sarcoma, the carcinoma showed different histological and phenotypic profiles.

Zebularine inhibits human acute myeloid leukemia cell growth in vitro in association with p15INK4B demethylation and reexpression

OBJECTIVE

The p15INK4B tumor suppressor is frequently silenced by promoter hypermethylation in myelodysplastic syndrome and acute myeloid leukemia (AML). Clinically approved DNA methylation inhibitors, such as 5-aza-2'-deoxycytidine, can reverse p15INK4B promoter methylation, but widespread clinical use of these inhibitors is limited by their toxicity and instability in aqueous solution. The cytidine analog zebularine is a stable DNA methylation inhibitor that has minimal toxicity in vitro and in vivo. We evaluated zebularine effects on p15INK4B reactivation and cell growth in vitro to investigate a potential role for zebularine in treating myeloid malignancies.

METHODS

We examined the specific effects of zebularine on reexpression of transcriptionally silenced p15INK4B and its global effects on cell cycle and apoptosis in AML cell lines and primary patient samples.

RESULTS

Zebularine treatment of AML193, which has a densely methylated p15INK4B promoter, results in a dose-dependent increase in p15INK4B expression that correlates with CpG island promoter demethylation and enrichment of local histone acetylation. We observed enhanced p15INK4B induction following co-treatment with zebularine and the histone deacetylase inhibitor Trichostatin A. Zebularine inhibits cell proliferation, arrests cells at G(2)/M, and induces apoptosis at dosages that effectively demethylate the p15INK4B promoter. Zebularine treatment of KG-1 cells and AML patient blasts with hypermethylated p15INK4B promoters also reactivates p15INK4B reexpression and induces apoptosis.

CONCLUSION

Zebularine is an effective inhibitor of p15INK4B methylation and cell growth in human AML in vitro. Our results extend the spectrum of zebularine effects to nonepithelial malignancies and provide a strong rationale for evaluating its clinical utility in the treatment of myeloid malignancies.

Pax-5 expression in nonhematopoietic tissues

We evaluated 123 formalin-fixed, paraffin-embedded samples, including neuroendocrine tumors, adult brain, mesonephric tissues, and from various other sites. A pre-B lymphoma cell line, Daudi, and a small cell carcinoma cell line, NCL-H128, were evaluated by Western blot. All tissues were immunostained by mouse monoclonal anti-Pax-5 antibody by using standard, synthetic polymer-based detection methods. Our study describes for the first time distribution of Pax-5 in adult brain tissue, including periaqueductal gray matter of the midbrain, area postrema of the medulla oblongata, and occasional cells of the spinal trigeminal nucleus (caudal nucleus). We confirm that Pax-5 is expressed regularly in poorly differentiated neuroendocrine tumors but never in well-differentiated classic carcinoid tumors. Pax-5 expression also was found readily in benign and malignant mesonephric tissues and focally in müllerian duct-derived tissues and tumors. Expression of Pax-5 in the Daudi and NCL-H128 cell lines was confirmed by Western blot. Together, these results are important for correct interpretation of results in immunophenotyping of undifferentiated tumors, for diagnosis of mesonephric carcinoma, and, potentially, for correct classification of neuroendocrine tumors in small biopsy samples.

RIZ1 repression is associated with insulin-like growth factor-1 signaling activation in chronic myeloid leukemia cell lines

RIZ1 is a histone methyltransferase whose expression and activity are reduced in many cancers. In chronic myelogenous leukemia (CML), blastic transformation is associated with loss of heterozygosity in the region where RIZ1 is located and with decreased RIZ1 expression. Forced RIZ1 expression in model CML blast crisis (BC) cell lines decreases proliferation, increases apoptosis and enhances differentiation. We characterized molecular mechanisms that may contribute to potential CML tumor suppressor properties of RIZ1. Several RIZ1-regulated genes involved in insulin-like growth factor-1 (IGF-1) signaling were identified using cDNA microarrays. RIZ1 was shown to associate with promoter regions of IGF-1 and to increase histone H3 lysine 9 methylation using chromatin immunoprecipitation assays. IGF-1-blocking antibody was used to demonstrate the importance of autocrine IGF-1 signaling in CML-BC cell line viability. Forced RIZ1 expression in CML-BC cell lines decreases IGF-1 receptor activation and activation of downstream signaling components extracellular signal-regulated kinase 1/2 and AKT. These results highlight the therapeutic potential of inhibiting IGF-1 pathway in the acute phase of CML.

Methylation status of cyclin-dependent kinase inhibitor genes within the transforming growth factor beta pathway in human T-cell lymphoblastic lymphoma/leukemia

Epigenetic silencing of downstream components of the transforming growth factor beta pathway including the cyclin-dependent kinase inhibitors (CDKIs) p15INK4B, p27KIP1 and p21CIP1 is implicated in the pathogenesis of some hematological malignancies. Loss of p15INK4B expression due to promoter methylation occurs frequently in human T-cell acute lymphoblastic leukemia (T-ALL) but the expression and methylation status of p27KIP1 remains to be characterized in T-ALL or T-cell lymphoblastic lymphoma (T-LBL). As well, while some have reported a high frequency of p21CIP1 methylation in ALL patient samples others have found the gene to be unmethylated in this disease and the relationship between p21CIP1 expression and promoter methylation has not been examined in T-LBL. Using RNase protection assays (RPA) and methylation specific PCR (MSP), we found p27KIP1 to be expressed and its promoter unmethylated in 20 of 20 (100%) and 28 of 28 (100%) T-LBL/ALL samples, respectively. In contrast, p21CIP1 mRNA was absent in 7 of 14 (50%) T-LBL biopsies and 5 of 6 (83%) T-ALL cell lines. However, like p27KIP1 there was no evidence of p21CIP1 promoter methylation by MSP or temporal temperature gradient electrophoresis (TTGE) analysis of 35 CpG sites in any of the 28 T-LBL/ALLs analyzed. Similar to T-ALL, we found p15INK4B mRNA was absent in 13 of 14 (93%) T-LBL biopsies and its promoter methylated in 6 of 10 (64%) cases. Our results indicate that p21CIP1 mRNA is absent in human T-LBL biopsies and T-ALL cell lines at a high frequency. However, unlike p15INK4B, reduced p21CIP1 expression in T-LBL/ALL is independent of dense promoter-associated CpG methylation. In contrast to some hematological malignancies p27KIP1 methylation does not appear to contribute significantly to T-LBL/ALL pathogenesis.

The replication error phenotype is associated with the development of distant metastases in hormonally treated patients with breast carcinoma

BACKGROUND

The positive replication error (RER+) phenotype defines a distinct subgroup of tumors with specific clinical, pathologic, and molecular features that have been documented well in hereditary nonpolyposis colon carcinoma (HNPCC). More recently, this phenotype also has been described in breast carcinoma.

METHODS

To determine the effect of RER phenotype on prognosis in patients with breast carcinoma, the authors examined matched archival tumor and normal tissue from 100 women with Stage I and Stage II breast carcinoma, all of whom were treated with hormonal therapy. Patients had been followed for a minimum of 5 years or until death. Seven microsatellite loci were examined, including hMLH1 (3p22, D3S1611), hMSH2 (2p16, D2S123), NM23-H1 (17q21), TP53-Dint (17p13), TP53-Penta (17p13), APC (5q21, D5S346), and HPC1 (1q24, D1S2883). The RER+ phenotype was defined as the presence of allelic shifts at three of the seven loci examined.

RESULTS

Twenty-five percent of patients were classified with the RER+ phenotype based on these criteria. The two groups, women with positive RER status and women with negative RER status, were comparable in terms of other factors that may influence prognosis: age, tumor size, lymph node status, disease stage, and estrogen receptor status. The development of distant metastases to the lung, liver, or brain was correlated significantly with the positive RER phenotype, with a relative risk of 2.625 (95% confidence interval, 1.059-6.057).

CONCLUSIONS

The presence of high-frequency RER+ may predict for the development of distant metastatic disease in patients with early-stage breast carcinoma who are treated with hormonal therapy.

Microsatellite mutations of transforming growth factor-beta receptor type II and caspase-5 occur in human precursor T-cell lymphoblastic lymphomas/leukemias in vivo but are not associated with hMSH2 or hMLH1 promoter methylation

In solid cancers, defective DNA mismatch repair (MMR) is most commonly caused by hMSH2 or hMLH1 mutations, or epigenetic silencing of hMLH1 by promoter hypermethylation, and results in the acquisition of characteristic frameshift microsatellite mutations of mononucleotide repeats located within the coding regions of defined target genes. We previously identified hMSH2 mutations in T-cell lymphoblastic lymphoma (T-LBL) patient tumor samples and others have reported coding region microsatellite mutations in T-cell acute lymphoblastic leukemia (T-ALL) cell lines. Thus, while MMR gene mutations are known to occur in some human T-lymphoblastic tumors in vivo, it is still unknown if the coding region microsatellite mutations detected in human cell lines also occur in vivo or if hMLH1 or hMSH2 promoter hypermethylation contributes to defective MMR in these tumors. We analyzed the TGFbetaRII (A)10 and caspase-5 (A)10 coding region repeats in 16 human T-LBL/ALL patient tumor samples and identified six with microsatellite mutations in one or both repeats. There was no evidence of hMSH2 or hMLH1 promoter methylation as assessed by standard methylation specific PCR or by a novel temporal temperature gradient electrophoresis (TTGE) method that analyzed 25 and 30 CpG sites in the hMLH1 and hMSH2 promoters, respectively. Our results indicate that coding region microsatellite mutations characteristic of defective MMR occur in some human T-LBL/ALL in vivo but not as a consequence of hMLH1 or hMSH2 promoter hypermethylation. Furthermore, the identification of TGFbetaRII and caspase-5 coding region mutations in vivo implicates these genes in the pathogenesis of human T-LBL/ALL.

T-cell variant of classical Hodgkin's lymphoma with nodal and cutaneous manifestations demonstrated by single-cell polymerase chain reaction

The atypical cells of CD30(+) cutaneous lymphoproliferative disorders (CD30CLD) are commonly of T-cell origin and frequently have a similar morphology as Hodgkin or Reed-Sternberg cells of Hodgkin's lymphoma (HL). HL is one of the tumors associated with CD30CLD. Although most studies support a B-cell derivation of the tumor cells in HL, recently a few cases of classical HL with T-cell genotype have been reported. We report a patient who presented with CD30CLD whose lymph nodes showed classical HL of mixed cellularity subtype at presentation. By single-cell PCR, the same clonal gene rearrangements of the T cell receptor-beta gene locus could be assigned to the CD30(+) and CD15(+) cells of both skin and lymph node. In a lymph node biopsy specimen taken in relapse after several courses of chemotherapy, the CD30(+) tumor cells were abundant. The T cell-derived tumor cells displayed aberrant expression of the Pax-5 gene in all specimens. A common clonal origin of both CD30CLD and HL of the lymph node in the patient presented here suggests that HL with T-cell genotype exists in association with CD30CLD as well as in sporadic cases and may share clonal origin with the skin tumor.

MSH2-deficient murine lymphomas harbor insertion/deletion mutations in the transforming growth factor beta receptor type 2 gene and display low not high frequency microsatellite instability

High-frequency microsatellite instability (MSI), defined as more than 20% unstable loci, is an inconsistent finding in hematologic malignancies; consequently, the significance of deficient DNA mismatch repair (MMR) to their pathogenesis has been questioned. To further investigate the relationship between MMR deficiency and genomic instability in hematologic malignancies, this study evaluated MSH2-/- murine lymphomas for insertion/deletion (ID) mutations within the transforming growth factor (TGF)-beta receptor type II (TbetaR-II) gene and MSI at 10 neutral microsatellites. The lymphomas displayed ID mutations within short mononucleotide runs of TbetaR-II at a high frequency, whereas nonmalignant tissue from corresponding animals lacked mutations. Loss of TbetaR-II transcripts and protein was seen in 6 of 7 murine lymphomas harboring acquired TbetaR-II mutations. In the analysis of paired nonmalignant and tumor DNA samples, low-frequency but not high-frequency MSI was found. Low-frequency MSI occurred in 8 of 20 lymphomas and 12 displayed microsatellite stability. MSI was even less frequent in nonmalignant tissue as only 3 of 20 samples displayed low-frequency MSI and 17 displayed stability. Evaluation of 20 single cell clones from the MSH2-/- lymphoma cell lines R25 and L15 identified high-frequency MSI in 4 and 2 clones, respectively. The remaining clones showed low-frequency MSI or stability. These findings suggest that acquired TbetaR-II mutations represent important inactivating events in tumor pathogenesis following MSH2 deficiency. Furthermore, for some hematolymphoid malignancies, the evaluation of cancer-associated genes for ID mutations may represent a more sensitive marker of MMR deficiency than evaluation of neutral microsatellites for high-frequency MSI. (Blood. 2000;95:1767-1772)

Ph-negative non-Hodgkin's lymphoma occurring in chronic phase of Ph-positive chronic myelogenous leukemia is defined as a genetically different neoplasm from extramedullary localized blast crisis: report of two cases and review of the literature

This report describes two cases of Philadelphia chromosome-negative (Ph(-)) non-Hodgkin's lymphomas (NHLs) recognized in patients with chronic phase Ph-positive (Ph(+)) chronic myelogenous leukemia (CML). Lymph node biopsy of patient 1 was initially diagnosed as diffuse large B cell non-Hodgkin's lymphoma (NHL, T cell rich variant), but at relapse showed immunoblastic features with a marked decrease of admixed lymphocyte components. Patient 2 presented with thickened parietal pleura which revealed a CD30-positive anaplastic large cell lymphoma showing null cell phenotype and genotype with abundant admixed neutrophils and lymphocytes. At the time of lymphoma diagnosis, the patients had CML for 33 and 10 months, respectively. DNA obtained from bone marrow cells at the time of lymphoma diagnosis showed BCR/ABL gene rearrangements by both Southern blot analysis and reverse transcription polymerase chain reaction (RT-PCR), but lacked both immunoglobulin and T cell receptor gene rearrangements. BCR gene rearrangement and BCR/ABL fusion gene were also identified in lymph node and pleural biopsies by Southern blot and RT-PCR analysis, respectively. However, both biopsy specimens also contained reactive lymphocytes and neutrophils, and no fusion signals between BCR and ABL genes were identified in the hyperdiploid lymphoma cells of either case by fluorescence in situ hybridization (FISH). These data suggest the lymphoma cells in both cases were not genetically associated with BCR/ABL. Therefore, these cases were not diagnosed as an extramedullary localized blast crisis in CML, but as Ph(-) NHLs. This represents the first definitive demonstration of peripheral B cell lymphoma occurring by a separate genetic pathway, lacking BCR/ABL, in patients with Ph(+) CML. A review of the literature identified two different subtypes of malignant lymphomas arising in patients with an antecedent or concurrent diagnosis of CML. The most common are T cell lymphomas displaying an immature thymic phenotype, while peripheral B cell lymphomas are more rare. Our study shows, however, that 'Ph(+) NHL' occurring in CML or acute lymphocytic leukemia (ALL) may represent an unrelated neoplasm, even if standard cytogenetic analysis reveals a Ph(+) chromosome, and that FISH is required to confirm whether a localized lymphoid neoplasm is either a true extramedullary localized blast crisis or genetically distinct neoplasm. Leukemia(2000) 14, 169-182.

Clonality of cutaneous B-cell infiltrates determined by microdissection and immunoglobulin gene rearrangement

Diagnosis of primary cutaneous B-cell lymphoma (PCBCL) is supported by the demonstration of a monoclonal B-cell population. Immunoglobulin heavy chain (IgH) gene-rearrangement analysis by polymerase chain reaction (PCR) is a reliable technique to detect B-cell monoclonality in paraffin-embedded tissue, but the presence of numerous reactive B lymphocytes in PCBCL may complicate the interpretation of clonality test results. To test this hypothesis, IgH gene-rearrangement analysis by PCR was performed on paraffin-embedded whole tissue sections of 19 cutaneous B-cell infiltrates diagnosed either as consistent with PCBCL (10 specimens) or unclassified lymphoid infiltrates (ULI) (9 specimens). In specimens that did not show monoclonal bands by IgH gene-rearrangement on DNA extracted from whole tissue sections, clonality assays were repeated on microdissected B-cell subpopulations suspicious for neoplastic cells. In the analysis of whole tissue sections, 4 (40%) of 10 specimens consistent with PCBCL showed one or two monoclonal bands, whereas 9 of 9 ULI specimens showed either a ladder or a smear. Clonality analysis of microdissected B-cell subpopulations showed 3 additional PCBCL specimens (total, 7 of 10) and 1 ULI specimen (total, 1 of 9) with unequivocal and reproducible monoclonal bands. Addition of microdissection increases the sensitivity of PCR-based B-cell clonality assay in PCBCL compared with analysis performed on the whole section (70% versus 40% monoclonal cases) and allows the recognition of a dominant clone in ULI specimens, possibly representing early PCBCL.

Cortical blindness as a manifestation of hypomagnesemia secondary to cisplatin therapy: case report and review of literature

Cisplatin is widely used in the treatment of solid tumors and is known to have a number of side effects including hypomagnesemia. We present a case report of a patient with a Stage IIA carcinoma of the cervix who initially was treated with radiotherapy and cisplatin and subsequently presented with sudden onset of blindness. The diagnosis was uncertain but the possibility of functional blindness was considered. Serum magnesium was low. Correction of this electrolyte abnormality resolved this profound visual symptom. This case emphasizes the importance of serially observing cisplatin-treated patients for the possible development of the clinical syndrome of magnesium deficiency.

Herpes virus type 8-negative primary effusion lymphoma associated with PAX-5 gene rearrangement and hepatitis C virus: a case report and review of the literature

At present, there is no case report of HHV8- primary effusion lymphoma (PEL) with t(9;14)(p13;q32) involving both PAX-5 and immunoglobulin heavy chain gene rearrangement, which is a rare translocation in B-cell non-Hodgkin's lymphoma, in an HIV- patient. We examined an HIV-seronegative 63-year-old Japanese man with hepatitis C virus-associated liver cirrhosis and hepatocellular carcinoma manifesting peritoneal lymphomatous effusion without tumor mass at any body site. The lymphoma cells were examined twice by light microscopy, immunohistochemistry, three-color flow cytometry, cytogenetics, and molecular analyses. The nuclear morphology of lymphoma cells was similar to that of large noncleaved cells, although the lymphoma cell size was a little smaller that of the usual large-cell lymphoma. Immunophenotyping of lymphoma cells in the ascitic fluid revealed a mature peripheral B-cell phenotype (CD5- CD10- CD19+ CD20+ CD22+ Ig G+ lambda+). Cytogenetics showed a clonal population: 45,X,-Y, der(2) t(2;6)(q31;p21.3), t(4;8)(q21;q11.2), der(6) t(2;6)(q31;p21.3) add(6)(q15), t(9;14)(p13;q32.3) [10]/47, idem, +der(6) t(2;6), +16[10]. Southern blot analysis revealed rearranged fragments with a probe for immunoglobulin heavy chain, some of which were a size similar to those with a PAX-5 gene probe. Polymorphism, not rearrangement, of the c-MYC gene, was also found. HHV8 and the Epstein-Barr virus were not detected by polymerase chain reaction. This case is the first report of an HHV8- PEL with t(9;14) involving a PAX-5 gene rearrangement in an HIV-seronegative patient. This primary effusion lymphoma manifested spontaneous regression without any therapy. These findings suggest that there may be an additional subcategory of primary effusion lymphoma that is not associated with HHV8 nor c-MYC(R) but is pathogenetically associated with the PAX-5 gene or hepatitis C virus.

Translocation (3;16)(q27;p11) in a patient with diffuse large B-cell lymphoma associated with the BCL-6 gene rearrangement

A patient with B-cell lineage diffuse large-cell lymphoma carrying the t(3;16)(q27;p11) and BCL-6 rearrangement is described. Cytogenetic studies showed 46,XY,t(3;16)(q27;p11.2)[.11]/46,idem,add(18)(q21)[7]/46,XY[2]. The chromosomal translocation involving the 3q27 locus was associated with the BCL-6 gene rearrangement identified by Southern blot analysis. This case involved systemic lymph nodes, as large as 3 cm in diameter, bilaterally in neck, axilla, and inguinal regions. The patient obtained complete remission with chemotherapy.

Chromosomal abnormalities in nodal and extranodal CD30+ anaplastic large cell lymphomas: infrequent detection of the t(2;5) in extranodal lymphomas

To determine the significance of the t(2;5)(p23;q35) translocation in nodal and extranodal anaplastic large cell lymphoma (ALCL), we performed cytogenetic, molecular genetic, and immunohistochemical analyses of tumor tissues from 11 patients with CD30+ ALCL. Three of five patients with nodal ALCL had additional infiltration of the skin. Six patients had extranodal ALCL, two had primary intestinal ALCL, three had a primary cutaneous ALCL, and one had osseous ALCL. Cytogenetic investigation detected the t(2;5) in all patients with nodal ALCL but not extranodal ALCL. Tumor cells in t(2;5)+ lesions also stained immunohistochemically for p80NPM/ALK, whereas no staining for p80NPM/ALK was detected in extranodal ALCL. Two extranodal lesions had NPM/ALK fusion transcripts detected by nested reverse transcriptase-polymerase chain reaction. Fluorescence in situ hybridization analysis of these two lymphomas showed in one case a significant number (4%) of cells with a split hybridization signal, indicative of disruption of the NPM gene. Additional recurrent breakpoints observed in extranodal ALCL were 1p36, 6p25, and 8q24. Loss of genetic material occurred at 6q in one extranodal ALCL. Our results suggest that the t(2;5) more frequently plays a pathogenetic role in primary nodal than in extranodal ALCL and that this translocation may not be the primary event in some CD30+ ALCL.

Three-color flow cytometry in the diagnosis of malignant lymphoma based on the comparative cell morphology of lymphoma cells and reactive lymphocytes

This study examines the identification of unusual cell populations highly associated with lymphoma cells (UCP-L) in diagnostic biopsy specimens using three-color flow cytometry (3-FCM). Patterns of surface antigen expression were used to compare the morphology of distinct lymphoid cell populations present in biopsy specimens and determine the presence or absence of UCP-L. UCP-L were identified by their larger size as compared to admixed reactive lymphocytes, and the method is based on the concept that neoplastic lymphoma cells are larger than reactive lymphocytes. The comparison of relative cell sizes was determined by overlaying forward scatter histograms by multicolor gating using PAINT-A-GATE software. In order for separate gates to be set on UCP-L and reactive cell populations, UCP-L had to fulfill one or more immunophenotypic criteria. These included: (1) belonging to a subset of B cell antigen-positive cells showing restricted expression of kappa or lambda light chains; (2) belonging to a subset of CD4-positive cells having dim or absent expression of CD45RA; (3) showing alterations in antigen expression (loss, dimmer or brighter); or (4) expressing an immunophenotype that is present on only rare cell populations or is absent from reactive lymph nodes. The immunophenotypic profiles of the respective cell populations were demonstrated by cubic representations to assess more easily the co-expression of three antigens. The common morphology of UCP-L as defined by forward and side scatter grams was consistent with a 'lymphoid appearance' except in several cases of HTLV-I-positive T cell lymphoma and gammadelta T cell lymphoma. The immunophenotypic profiles of UCP-L were confirmed to correspond to the presumptive lymphoma cell population by use of a live gating procedure on the large cells, which eliminated interference by reactive cells or necrotic tissue fragments. Using this method, we identified UCP-L in 208 of 293 (71%) consecutive cases of non-Hodgkin's lymphomas, while no UCP-L were seen in 72 cases of non-specific hyperplasia of lymph nodes. Twenty-seven cases could not properly be examined about the existence of UCP-L because of massive necrosis, extensive fibrosis or strong non-specific staining reactions of unknown cause. When those cases were eliminated from the analysis, 80% of non-Hodgkin's lymphoma were found to contain UCP-L. In B cell lymphoma, the incidence of UCP-L in nodal lymphomas (80%) was much higher than in extranodal lymphomas (47%). Only one of 21 cases of Hodgkin's lymphoma was found to have UCP-L. The 3-FCM procedure was validated by the combined use of immunohistochemistry, morphologic examination, cytogenetic and antigen receptor gene rearrangement analysis by Southern blot hybridization. Our findings indicate that detection of UCP-L by 3-FCM is a reliable method to distinguish non-Hodgkin lymphomas from reactive hyperplasias in the majority of cases, even when the reactive cell population predominates over the malignant cell population.

Cloning, expression, and chromosomal localization to 11p12-13 of a human LIM/HOMEOBOX gene, hLim-1

We have identified a putative transcription factor, designated hLim-1, from human fetal brain using degenerate polymerase chain reaction (PCR) and cDNA library screening. The deduced open reading frame, derived from sequencing a 3.0-kb hLim-1 cDNA, encodes a protein of 384 amino acids with two cysteine-rich LIM domains and one homeobox (HOX) DNA-binding domain. The nucleotide sequence of hLim-1 cDNA is 87% identical to mouse Lim-1 and the predicted amino acid sequence is greater than 97% conserved. Expression patterns of hLim-1 were evaluated by Northern analysis and reverse transcription (RT)-PCR coupled with Southern blotting. HLim-1 expression was observed in human brain, thymus, and tonsillar tissue. Expression of hLim-1 was also observed in 58% of acute myelogenous leukemia (AML) cell lines and in four of five primary samples from patients with chronic myeloid leukemia (CML) in myeloid blast transformation. The gene encoding hLim-1 was mapped using fluorescence in situ hybridization (FISH) to human chromosome 11p12-13. The expression pattern and structural characteristics of the hLim-1 gene suggest that it encodes a transcriptional regulatory protein involved in the control of differentiation and development of neural and lymphoid cells. Its expression in CML in blast crisis suggests that it may be involved with progression in this disease; a prospective study is required to confirm this.

Loss of functional cell surface transforming growth factor beta (TGF-beta) type 1 receptor correlates with insensitivity to TGF-beta in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia in Western countries, and there is significant variability in survival within CLL clinical stages. Earlier studies showed that CLL cells produce and are usually growth inhibited by transforming growth factor beta type 1 (TGF-beta1), suggesting a mechanism for the clinically indolent course of most CLL. Here we studied the mechanism by which CLL cells from about one-third of the patients are insensitive to TGF-beta1. Of the 13 patients studied, CLL cells isolated from the peripheral blood of 8 patients were sensitive to growth inhibition by TGF-beta1, as determined by incorporation of tritiated thymidine, whereas those from 5 patients were completely resistant to TGF-beta1. As judged by binding of radiolabeled TGF-beta1 followed by cross-linking and immunoprecipitation with anti-receptor antisera, CLL cells sensitive to TGF-beta1 exhibited normal cell surface expression of both types 1 and 2 TGF-beta receptors. In contrast, all CLL cells resistant to TGF-beta1 exhibited no detectable surface type I receptors able to bind TGF-beta1, but normal expression of type II receptors. Both TGF-beta1-sensitive and TGF-beta1-resistant CLL cells contained normal amounts of both type 1 and type 2 receptor mRNAs. Specific loss of type 1 receptor expression represents a new mechanism by which cells acquire resistance to TGF-beta1-mediated growth inhibition in the development and progression of human lymphoproliferative malignancies.

Defects of the mismatch repair gene MSH2 are implicated in the development of murine and human lymphoblastic lymphomas and are associated with the aberrant expression of rhombotin-2 (Lmo-2) and Tal-1 (SCL)

Mutations in the DNA mismatch repair (MMR) gene hMSH2 underlie a novel pathway of tumorigenesis for some cancers of epithelial origin. Mice deficient in MSH2 are susceptible to lymphomas but defects in this gene have not been identified in human lymphoid tumors. To determine if the lymphomas these mice develop are related to a particular subtype of human lymphoma we evaluated 20 clinically ill homozygous MSH2-/- mice ranging in age from 2 to 13 months. The murine tumors comprised a single histopathologic entity representing the malignant counterpart of precursor thymic T cells and closely resembled human precursor T-cell lymphoblastic lymphoma (LBL). Evaluation of the expression of three T-cell malignancy associated genes showed that Rhombotin-2 (RBTN-2 also known as Lmo-2), TAL-1 (also known as SCL), and HOX-11 were expressed in 100%, 40%, and 0% of the murine tumors, respectively. The MSH2-/- murine model of precursor T-cell LBL was substantiated by the finding of a nearly identical expression profile of RBTN-2, TAL-1, and HOX-11 in 10 well-characterized cases of human LBL. Direct evidence for MSH2 abnormalities in human LBL was established by sequence analysis of exon 13 of hMSH2, which revealed coding region mutations in 2 of 10 cases. Our findings implicate defects in the MMR system with the aberrant expression of T-cell specific proto-oncogenes and define a new pathway of human lymphomagenesis.

Peripheral CD4+ CD8- gammadelta T cell lymphoma: a case report with multiparameter analyses

A 72-year-old Japanese man presented with CD4+ T cell receptor (TCR) gammadelta T cell lymphoma involving bilateral cervical lymph nodes. No involvement by tumor was observed in the liver, spleen, nasal cavity, or bone marrow throughout his clinical course. Although the tumor adequately responded to chemotherapy and irradiation, he relapsed with short remission and a slowly aggressive clinical course, and died 24 months after onset. Simultaneous expression of TCR gammadelta with other T-cell antigens on the lymphoma cells was analyzed by 3-color flow cytometry (3-FCM), and showed a unique phenotype CD3+ CD4+ CD8- CD7- CD5+ CD2++ TCR alphabeta (WT31)- betaF1-TCR gammadelta1 (11F2)+ TCR delta1+. Cytogenetic analysis showed 79-81 and structural abnormalities consisting of del(1)(p11) and i(17)(q10). But no abnormality was identified in chromosome 7. DNA analysis revealed gene rearrangements of TCRgamma and delta, while a nongerm line band in TCRbeta was aberrantly seen. These observations suggest a new subtype of gammadelta T-cell lymphoma, which is characterized by CD4 positivity and by a clinical course not as aggressive as other predominant subtypes.

A dominant inhibitory mutant of the type II transforming growth factor beta receptor in the malignant progression of a cutaneous T-cell lymphoma

In many cancers, inactivating mutations in both alleles of the transforming growth factor beta (TGF-beta) type 11 receptor (TbetaRII) gene occur and correlate with loss of sensitivity to TGF-beta. Here we describe a novel mechanism for loss of sensitivity to growth inhibition by TGF-beta in tumor development. Mac-1 cells, isolated from the blood of a patient with an indolent form of cutaneous T-cell lymphoma, express wild-type TbetaRII and are sensitive to TGF-beta. Mac-2A cells, clonally related to Mac-1 and isolated from a skin nodule of the same patient at a later, clinically aggressive stage of lymphoma, are resistant to TGF-beta. They express both the wild-type TbetaRII and a receptor with a single point mutation (Asp-404-Gly [D404G]) in the kinase domain (D404G-->TbetaRII); no TbetaRI or TbetaRII is found on the plasma membrane, suggesting that D404G-TbetaRII dominantly inhibits the function of the wild-type receptor by inhibiting its appearance on the plasma membrane. Indeed, inducible expression, under control of a tetracycline-regulated promoter, of D404G-TbetaRII in TGF-beta- sensitive Mac-1 cells as well as in Hep3B hepatoma cells results in resistance to TGF-beta and disappearance of cell surface TbetaRI and TbetaRII. Overexpression of wild-type TbetaRII in Mac-2A cells restores cell surface TbetaRI and TbetaRH and sensitivity to TGF-beta. The ability of the D404G-TbetaRH to dominantly inhibit function of wild-type TGF-beta receptors represents a new mechanism for loss of sensitivity to the growth-inhibitory functions of TGF-beta in tumor development.

The t(2;5) chromosomal translocation is not a common feature of primary cutaneous CD30+ lymphoproliferative disorders: comparison with anaplastic large-cell lymphoma of nodal origin

Primary cutaneous CD30+ lymphoproliferative disorders (LPDs), including lymphomatoid papulosis (LyP), anaplastic and nonanaplastic CD30+ large-cell lymphoma, and borderline cases, comprise a clinical and histologic spectrum. Primary cutaneous and primary nodal CD30+ anaplastic large-cell lymphomas (ALCLs) are distinct clinical entities that have identical morphologic features but differ in age of onset, immunophenotype, and prognosis. It can be difficult to distinguish primary cutaneous from nodal ALCLs that secondarily involve the skin, which is important because these diseases differ significantly in response to treatment and clinical outcome. The t(2;5) chromosomal translocation is highly associated with primary CD30+ ALCL of nodal origin. The possible occurrence of t(2;5) in primary cutaneous CD30+ LPDs has not been studied extensively, and it remains to be determined if expression of this translocation can be used to distinguish primary cutaneous ALCL from nodal ALCL that secondarily involves the skin. To address these issues, we studied 43 cases of cutaneous and nodal CD30+ LPDs using reverse transcriptase-polymerase chain reaction (RT-PCR) and/or immunohistochemistry. We found no evidence for the t(2; 5) translocation in 14 cases of primary cutaneous CD30+ LPDs, which included 10 cases of LyP, three cases of primary cutaneous CD30+ ALCL, and one borderline case. These findings were in marked contrast to CD30+ ALCL of nodal origin, in which 19 of 29 (66%) cases were positive for t(2;5), including all five cases with secondary skin involvement. Our results support the hypothesis that (1) primary cutaneous CD30+ LPDs (including LyP) and primary nodal ALCL are distinct diseases that differ in clinical behavior and pathogenesis and (2) differential expression of t(2;5) can help to distinguish between primary cutaneous CD30+ LPDs and ALCL of nodal origin.

New insights into peripheral T-cell lymphomas

Peripheral T-cell lymphomas comprise a morphologically diverse group of malignant lymphoproliferative disorders that arise from postthymic T cells. Currently, there exists no universally accepted system of classification of peripheral T-cell lymphoma. Recent efforts to elucidate pathogenetic mechanisms and define recognizable entities have begun to clarify the nature of these tumors. These and future studies may one day lead to a unified system of classification of peripheral T-cell lymphoma that is reproducible, biologically relevant, and more predictive of clinical behavior and prognosis.

SBH-1, a novel Reed-Sternberg-like cell line capable of inducing tumors in SCID mice: immunophenotypic, cytogenetic, and cytokine expression profiles

A new cell line, SBH-1, with the morphologic, immunophenotypic, and karyotypic features consistent with those of Reed-Sternberg (RS) and Hodgkin (H) cells, has been established from the pleural effusion of a patient. The cytologic appearance of SBH-1 cells is characteristic of multinucleate RS and mononuclear H cells, all containing inclusion-like nucleoli. The SBH-1 cells express CD30, CD15, CD25, CD71, CD45, CD20, CD22, and bcl-2 protein and are negative for epithelial membrane antigen. Cytogenetic analysis showed multiple clonal abnormalities with breakpoints at 14q32, 6q21, and 11q23. The Ig heavy chain genes and both Ig light chain genes were rearranged in SBH-1 cells, whereas the bcl-2 gene was in germline configuration. Messages for the cytokines interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha, and transforming growth factor-beta and the cytokine receptors IL-2R, IL-4R, IL-6R, and IL-7R were detected by reverse transcription-polymerase chain reaction analysis. Xenotransplantation of SBH-1 cells into severe combined immunodeficient (SCID) mice led to local and disseminated tumor growth. The cytologic, histologic, and immunohistochemical features of SBH-1 cells in SCID mouse tumors were typical of RS and H cells. The SBH-1 cell line will be useful in the study of RS and H cell biology, inasmuch as it represents a cell line obtained from a previously untreated patient.