Topo IIα gene alterations correlated with survival in patients with diffuse large B-cell lymphoma

Aberrant expression and genetic alteration of c-MYC in anaplastic large cell lymphoma

PURPOSE

c-MYC plays an important role in regulating cellular growth and apoptosis, and it is aberrantly expressed in many human malignancies. Although c-MYC has been extensively investigated in Burkitt lymphoma and diffuse large B cell lymphoma, little has been reported in anaplastic large cell lymphoma (ALCL). The aim of this study was to investigate the expression and genetic alterations of c-MYC in primary systemic ALCL, characterize its clinicopathologic features and immunophenotypes, and discuss their implications in prognosis.

METHODS

Tissue microarrays using samples from 85 ALCL patients were used to evaluate expression of c-MYC and anaplastic lymphoma kinase (ALK). c-MYC and ALK genetic alterations were detected using fluorescence in situ hybridization. The Kaplan-Meier and multivariate Cox regression methods were used for survival analysis.

RESULTS

c-MYC was expressed in 24 of 85 samples (28.2%), and ALK was expressed in 54 (63.5%). c-MYC and ALK were co-expressed in 16 samples (18.8%). c-MYC expression and c-MYC and ALK co-expression increased with ALCL clinical stages and the International Prognostic Index (IPI) score (p < 0.05). Fifty of the samples (58.8%) had ALK rearrangement, and 18 (22.1%) had aneuploidy. c-MYC rearrangement was not detected, but aneuploidy was observed in 19 cases (22.4%). c-MYC aneuploidy was significantly different based on c-MYC expression and the IPI score (p < 0.05). c-MYC was a significant independent prognostic factor for progression-free survival and overall survival in patients with ALCL.

CONCLUSION

c-MYC protein expression and c-MYC aneuploidy could predict worse survival in patients with ALCL.

Targeting nucleolin for better survival in diffuse large B-cell lymphoma

Anthracyclines have been a cornerstone in the cure of diffuse large B-cell lymphoma (DLBCL) and other hematological cancers. The ability of anthracyclines to eliminate DLBCL depends on the presence of topoisomerase-II-alpha (TopIIA), a DNA repair enzyme complex. We identified nucleolin as a novel binding partner of TopIIA. Abrogation of nucleolin sensitized DLBCL cells to TopIIA targeting agents (doxorubicin/etoposide). Silencing nucleolin and challenging DLBCL cells with doxorubicin enhanced the phosphorylation of H2AX (γH2AX-marker of DNA damage) and allowed DNA fragmentation. Reconstitution of nucleolin expression in nucleolin-knockdown DLBCL cells prevented TopIIA targeting agent-induced apoptosis. Nucleolin binding to TopIIA was mapped to RNA-binding domain 3 of nucleolin, and this interaction was essential for blocking DNA damage and apoptosis. Nucleolin silencing decreased TopIIA decatenation activity, but enhanced formation of TopIIA-DNA cleavable complexes in the presence of etoposide. Moreover, combining nucleolin inhibitors: aptamer AS1411 or nucant N6L with doxorubicin reduced DLBCL cell survival. These findings are of clinical importance because low nucleolin levels versus high nucleolin levels in DLBCL predicted 90-month estimated survival of 70% versus 12% (P<0.0001) of patients treated with R-CHOP-based therapy.

High expression of Bcl-2 predicts poor outcome in diffuse large B-cell lymphoma patients with low international prognostic index receiving R-CHOP chemotherapy

The prognostic significance of Bcl-2, Bcl-6, p53, topoisomerase II, and β-tubulin expression was evaluated in diffuse large B-cell lymphoma (DLBCL) patients treated with cyclophosphamide, doxorubicin, vincristine, prednisolone, and rituximab. Eight-year progression-free survival (PFS, P = 0.006) and overall survival (OS, P = 0.001) of patients with high Bcl-2 expression were significantly inferior to those of patients with low expression without prognostic significance of Bcl-6, p53, topoisomerase II, and β-tubulin expression. High expression of Bcl-2 was associated with poor PFS (P = 0.045) and OS (P = 0.004) only in patients with low international prognostic index (IPI). In multivariate analysis, high expression of Bcl-2 was a significant independent prognostic factor of poor PFS (P = 0.026) and OS (P = 0.007) along with high IPI. In conclusion, the expression of Bcl-2 may be a useful prognostic factor, especially in DLBCL patients with low IPI.

HMGB1 overexpression correlates with poor prognosis in early-stage squamous cervical cancer

High mobility group box 1 (HMGB1) is associated with tumor progression and a poor prognosis; microtubule-associated protein 1 light chain 3 (LC3) plays a critical role in autophagy. However, the roles of HMGB1 and LC3 in squamous cervical cancer (SCC) remain unclear. An array of 166 early-stage SCC, 62 cervical intraepithelial neoplasia (CIN), and 50 normal cervical tissue samples was assessed. HMGB1 and LC3 protein levels were examined by immunohistochemistry, and the associations of HMGB1 and LC3 levels with clinicopathological characteristics evaluated, to assess their prognosis significance. High nuclear HMGB1 levels were detected in 72.9% SCC cases; 16% cases showed cytoplasmic expression of HMGB1 in cancer cells with low nuclear expression. Interestingly, HMGB1 levels in SCC samples were significantly higher than CIN and control specimens, while lower LC3 expression was found in SCC samples (P < 0.001). Nuclear HMGB1 expression was weakly negatively correlated to LC3 amounts (r = -0.254, P = 0.001). High nuclear HMGB1 levels were associated with vascular metastasis (P < 0.05). In addition, cytoplasmic HMGB1 expression was associated with lymph node metastasis (P < 0.05). Furthermore, high nuclear HMGB1 levels and cytoplasmic HMGB1 expression predicted poor overall survival (OS) and disease-free survival (DFS). Meanwhile, high LC3 expression was associated with favorable prognosis. Multivariate analysis showed that both nuclear and cytoplasmic HMGB1 expressions were independent prognostic factors for overall- and disease-free survival, along with nodule metastasis. HMGB1 overexpression plays a significant role in SCC progression. Both nuclear and cytoplasmic HMGB1 are independent factors for poor prognosis in early-stage SCC.

Lack of topoisomerase copy number changes in patients with de novo and relapsed diffuse large B-cell lymphoma

Topoisomerase (TOP) gene copy number changes may predict response to treatment with TOP-targeting drugs in cancer treatment. This was first described in patients with breast cancer and is currently being investigated in other malignant diseases. TOP-targeting drugs may induce TOP gene copy number changes at relapse, with possible implications for relapse therapy efficacy. TOP gene alterations in lymphoma are poorly investigated. In this study, TOP1 and TOP2A gene alterations were investigated in patients with de novo diffuse large B-cell lymphoma (DLBCL) (n = 33) and relapsed DLBCL treated with chemotherapy regimens including TOP2-targeting drugs (n = 16). No TOP1 or TOP2A copy number changes were found. Polysomy of chromosomes 20 and 17 was seen in 3 of 25 patients (12%) and 2 of 32 patients (6%) with de novo DLBCL. Among relapsed patients, chromosome polysomy was more frequently observed in 5 of 13 patients (38%) and 4 of 16 patients (25%) harboring chromosome 20 and 17 polysomy, respectively; however, these differences only tended to be significant (p = 0.09 and p = 0.09, respectively). The results suggest that TOP gene copy number changes are very infrequent in DLBCL and not likely induced by TOP2-targeting drugs. Increased polyploidy of chromosomes 17 and 20 among patients with relapsed DLBCL may reflect genetic compensation in the tumor cells after TOP2 inhibition, but is more likely due to the increased genetic instability often seen in progressed cancers. Therefore, it is unlikely that TOP1 and TOP2A gene alterations can be used as predictive markers for response to treatment with TOP2-targeting drugs in patients with DLBCL.

Analysis of clinical characteristics of 516 patients with non-Hodgkin's lymphoma in Shanghai area

The aim was to determine the clinical and cytogenetic characteristics of non-Hodgkin's lymphoma (NHL) in Shanghai. A retrospective analysis was conducted in 516 patients with NHL. Patient clinical data, including age, sex, diagnosis, immunophenotypes, and karyotypes, were collected. The median age was 58 years. There was a male predominance in all NHL, except extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. Patients with B cell NHL (1.5%) expressed CD3. T cell NHL patients (11.5%) expressed CD20. Epstein-Barr virus latent integral membrane protein 1, BCL6, CD10, Bcl-2, CD68, myeloperoxidase, CD99, CD30, CD15, and CD43 were present in various types of NHL. Complex karyotypes accounted for 92.3% of the 73.7% patients with abnormal karyotypes. Immunoglobin heavy chain gene translocation was present in 60.3% of B cell and 23.7% of T/NK cell neoplasms. Understanding the complex clinicopathological and molecular features of NHL may help with prognosis and serve as targets for treatments.

Over-expression of Thioredoxin-1 mediates growth, survival, and chemoresistance and is a druggable target in diffuse large B-cell lymphoma

Diffuse Large B cell lymphomas (DLBCL) are the most prevalent of the non-Hodgkin lymphomas and are currently initially treated fairly successfully, but frequently relapse as refractory disease, resulting in poor salvage therapy options and short survival. The greatest challenge in improving survival of DLBCL patients is overcoming chemo-resistance, whose basis is poorly understood. Among the potential mediators of DLBCL chemo-resistance is the thioredxoin (Trx) family, primarily because Trx family members play critical roles in the regulation of cellular redox homeostasis, and recent studies have indicated that dysregulated redox homeostasis also plays a key role in chemoresistance. In this study, we showed that most of the DLBCL-derived cell lines and primary DLBCL cells express higher basal levels of Trx-1 than normal B cells and that Trx-1 expression level is associated with decreased patients survival. Our functional studies showed that inhibition of Trx-1 by small interfering RNA or a Trx-1 inhibitor (PX-12) inhibited DLBCL cell growth, clonogenicity, and also sensitized DLBCL cells to doxorubicin-induced cell growth inhibition in vitro. These results indicate that Trx-1 plays a key role in cell growth and survival, as well as chemoresistance, and is a potential target to overcome drug resistance in relapsed/refractory DLBCL.