Tagged: Lymphoma

Oncotarget

Synergy of HDACi, PARPi and Chemotherapeutics Against Blood Cancer

October 19, 2022

Researchers investigated the efficacy of HDAC inhibitors in combination with PARP inhibitors and chemotherapeutic drugs in multiple blood cancer cell lines.

Synergy of HDACi, PARPi and Chemotherapeutics Against Blood Cancer
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Chromatin constitutes chromosomes in eukaryotic cells and comprises DNA and proteins. Chromosomes produce proteins and enzymes that are essential for cellular function and maintenance, including DNA repair. A critical process for DNA repair is poly(ADP-ribosyl)ation, or PARylation.

PARylation is triggered by poly(ADP ribose) polymerase (PARP) enzymes. When DNA becomes damaged, PARP enzymes bind to the damaged location in the cell. In cancer cells, however, this natural process can be counterproductive in respect to cancer treatment. PARylation can produce DNA repair mechanisms in cancer cells that can lead to cell death evasion and even drug resistance. Inhibiting PARylation may be a viable therapeutic strategy for cancer treatment.

HDAC Inhibitors

Histones, the main proteins that constitute chromatin, undergo post-translational modifications that regulate gene expression. Histone acetylation is an important epigenetic process that affects gene expression by relaxing the chromatin structure, making chromatin remodeling more feasible. Histone deacetylases (HDACs) are enzymes that can have the opposite effect. Histone deacetylation makes the chromatin more compact and difficult to remodel. The overexpression of HDAC has also been associated with tumorigenesis. Histone deacetylase inhibitors (HDACi) are a class of therapeutics that have shown promise in the treatment of hematologic malignancies (blood cancer) and solid tumors.

“Overexpression of HDACs has been associated with tumorigenesis by down-regulation of tumor suppressor genes [3, 4]; hence, HDAC inhibitors (HDACi) including vorinostat (SAHA), romidepsin (Rom), panobinostat (Pano) and belinostat have been approved by the United States Food and Drug Administration for the treatment of hematologic and other malignancies [5]. These inhibitors restore appropriate gene expression, resulting in induction of cell differentiation, cell cycle arrest and apoptosis [6].”

The Study

In a new study, researchers Benigno C. Valdez, Yago Nieto, Bin Yuan, David Murray, and Borje S. Andersson from the Department of Stem Cell Transplantation and Cellular Therapy at the University of Texas MD Anderson Cancer Center and the Cross Cancer Institute’s Department of Experimental Oncology at the University of Alberta investigate the efficacy of HDACi in combination with PARP inhibitors (PARPi) and chemotherapeutic drugs to treat hematologic cancer. On October 14, 2022, their research paper was published in Volume 13 of Oncotarget, entitled, “HDAC inhibitors suppress protein poly(ADP-ribosyl)ation and DNA repair protein levels and phosphorylation status in hematologic cancer cells: implications for their use in combination with PARP inhibitors and chemotherapeutic drugs.”

“Despite their preclinical efficacy, HDACi do not seem to be clinically highly effective as monotherapy, and potentially more effective anti-tumor activity is observed when they are combined with other anti-cancer drugs [7–9].”

Studies on the interactions of HDACi with PARPi in cancers of the blood are limited, especially when combined with chemotherapeutic agents. The researchers used a panel of hematologic cancer cell lines (acute myeloid leukemia, T-cell acute lymphoblastic leukemia, chronic myeloid leukemia, and multiple myeloma) and patient-derived cell samples to study the effect of HDACi (including SAHA (Vorinostat), panobinostat (Pano), romidepsin (Rom) and trichostatin A (TSA)) on PARylation. In addition, the team looked at the efficacy of HDACi combined with PARPi, including Olaparib (Ola) and niraparib (Npb), and with chemotherapeutic agents gemcitabine (Gem), busulfan (Bu) and melphalan (Mel).

Results

The researchers found that hematologic cancer cell lines and patient-derived cell samples exposed to various HDACi resulted in a significant caspase-independent inhibition of protein PARylation. HDACi-mediated inhibition of protein PARylation was mainly catalyzed by PARP1. These findings suggest that HDACi could potentially be used in combination with PARP inhibitors and chemotherapeutic drugs to treat blood cancers.

“Our results indicate that the anti-tumor efficacy of HDACi is partly due to down-regulation of PARylation, which negatively affects the status of DNA repair proteins. This repair inhibition, combined with the high levels of oxidative and DNA replication stress characteristic of cancer cells, could have conferred these hematologic cancer cells not only with a high sensitivity to HDACi but also with a heightened dependence on PARP and therefore with extreme sensitivity to combined HDACi/PARPi treatment and, by extension, to their combination with conventional DNA-damaging chemotherapeutic agents. The observed synergism of these drugs could have a major significance in improving treatment of these cancers.”

Conclusion

HDACi drugs can inhibit PARylation. The combination of HDACi-mediated inhibition of PARylation was complemented by PARPi and chemotherapeutic agents in multiple blood cancer cell lines. The efficacy of this combined treatment was superior to that of any single agent, supporting the further clinical development of HDACi in cancer therapy. These findings could potentially be used to improve the treatment of hematologic cancers.

“In conclusion, our results provide a molecular explanation for the HDACi-mediated inhibition of DNA repair in hematologic cancer cells and support the combinatorial application of HDACi, PARPi and chemotherapeutic agents for the treatment of hematologic malignancies.”

Click here to read the full research paper published by Oncotarget. 

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Oncotarget is an open-access journal that publishes primarily oncology-focused research papers in a continuous publishing format. These papers are available at no cost to readers on Oncotarget.com. Open-access journals have the power to benefit humanity from the inside out by rapidly disseminating information that may be freely shared with researchers, colleagues, family, and friends around the world.

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Oncotarget

Epigenetics and Immunotherapy Combined Fights Rare Lymphoma

August 24, 2022

In a new Oncotarget study, researchers assessed an epigenetic and immunotherapy treatment regimen among patients with blastic mantle cell lymphoma (bMCL).

Mantle cell lymphoma
Mantle cell lymphoma
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Mantle cell lymphoma (MCL) is a type of non-Hodgkin’s lymphoma (NHL) that is aggressive, difficult to treat and typically affects older adults. Recurrence and mortality rates among patients with MCL have remained high, despite recent therapeutic advances. Blastic mantle cell lymphoma (bMCL) is a rare subtype of MCL associated with a worse disease trajectory.

“Despite recent advances, MCL is incurable except with allogeneic stem cell transplant. Blastic mantle cell lymphoma (bMCL) is a rarer subtype of cMCL associated with an aggressive clinical course and poor treatment response, frequent relapse and poor outcomes.”

In previous studies, researchers reported that a combination of epigenetic and immunotherapy treatments may have synergistic activity and offer better outcomes in patients with MCL. In the current study, Francis R. LeBlanc, Zainul S. Hasanali, August Stuart, Sara Shimko, Kamal Sharma, Violetta V. Leshchenko, Samir Parekh, Haiqing Fu, Ya Zhang, Melvenia M. Martin, Mark Kester, Todd Fox, Jiangang Liao, Thomas P. Loughran, Juanita Evans, Jeffrey J. Pu, Stephen E. Spurgeon, Mirit I. Aladjem, and Elliot M. Epner from Pennsylvania State University College of Medicine, Penn State Hershey Cancer Institute, Winter Haven Hospital Cassidy Cancer Center, Icahn School of Medicine at Mount Sinai, National Cancer Institute, University of Virginia, UVA Cancer Center, University of Arizona College of Medicine, Oregon Health and Science University, and Beverly Hills Cancer Center used samples from a previous trial to perform correlative studies focused on clinical results in patients with blastic MCL. On August 16, 2022, their research paper was published in Volume 13 of Oncotarget, entitled, “Combined epigenetic and immunotherapy for blastic and classical mantle cell lymphoma.”

Epigenetic and Immunotherapy

Epigenetic therapy includes a range of drugs that can target epigenetic mechanisms, including DNA methylation and posttranslational modifications of histones. For example, vorinostat (SAHA; a histone deacetylase inhibitor) and cladribine (chemotherapy that also inhibits DNA methylation) are epigenetic agents. Rituximab, a maintenance immunotherapeutic agent, is a CD20-directed monoclonal antibody. These three treatments combined encompass a novel potential epigenetic and immunotherapy treatment regimen (SCR) for mantle cell lymphoma (MCL).

“Relapsed and [treatment] naïve MCL patients were treated with vorinostat (SAHA), cladribine and rituximab (SCR) regimen and followed for OS [overall survival], progression free survival (PFS) and with correlative basic science studies to investigate potential mechanisms of action of this epigenetic/immunotherapy combination.”

The Study

Since blastic MCL patients are rare, only 13 bMCL (four relapsed, nine previously untreated) patients treated with the SCR regimen were assessed in the prospective part of this study. All patients were male and Caucasian, and the median age at diagnosis was 62 years old. The patients were treated until they achieved remission, met the criteria for removal from the study, withdrew from the study, or passed away. Four patients were changed from rituximab to ofatumumab (a potent fully-human anti-CD20 antibody) due to rituximab intolerance (allergies, reactions) or lack of efficacy.

“Of 13 bMCL patients, all patients responded to therapy, with 12 patients meeting criteria for remission (CR, n = 6; PR, n = 6). Of those achieving CR, 5 remain in CR more than 5 years after diagnosis.”

Results

After a median of 4.8 cycles of therapy, 12 patients achieved a complete response (CR), and one patient maintained stable disease (SD). The patients reported an increased overall survival greater than 40 months, and several patients maintained durable remissions without relapse for longer than five years. These results are remarkably superior to current treatment regimens with conventional chemotherapy, which range from 14.5-24 months among bMCL patients.

“The median OS of 43.4 months and PFS of 17.3 months for MCL patients with blastic disease treated with SCR therapy is one of the most important outcomes in this study.”

Another important finding was that the G/A870 CCND1 polymorphism was a strong predictor of blastic MCL, nuclear localization of cyclinD1 and response to SCR therapy. The team identified two distinct mechanisms of resistance to SCR therapy. The researchers reported that the loss of CD20 expression and evading treatment by seeking sanctuary in the central nervous system were two major resistance mechanisms to SCR therapy. 

“These data indicate that administration of epigenetic agents improves efficacy of anti-CD20 immunotherapies.”

Conclusion

Although the study sample was relatively small, the researchers’ results are promising. The SCR regimen was demonstrated to be an effective epigenetic and immunotherapy treatment for mantle cell lymphoma, with long-term remissions and improved overall survival in bMCL patients. Researchers revealed important insights into the mechanisms of action of SCR and potential resistance mechanisms. This study also highlights the potential for future research exploring the efficacy of SCR in other cancers, along with other predictive biomarkers of response.

“This approach is promising in the treatment of MCL and potentially other previously treatment refractory cancers.”

Click here to read the full research paper published by Oncotarget. 

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Oncotarget is an open-access journal that publishes primarily oncology-focused research papers in a continuous publishing format. These papers are available at no cost to readers on Oncotarget.com. Open-access journals have the power to benefit humanity from the inside out by rapidly disseminating information that may be freely shared with researchers, colleagues, family, and friends around the world.

For media inquiries, please contact media@impactjournals.com.

Oncotarget

Trending With Impact: Dual Requirement in Stem Cell Leukemia/Lymphoma

May 13, 2022

For the first time, researchers revealed the protein interactome, phospho-proteome and total proteome for the oncogenic fusion protein BCR-FGFR1.

Figure 6: Signaling pathways activated by BCR-FGFR1.
Figure 6: Signaling pathways activated by BCR-FGFR1.

The Trending With Impact series highlights Oncotarget publications attracting higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Oncotarget.com.

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Chromosomes are found in the nucleus of cells and consist of proteins and tightly coiled strands of DNA. During cell division, chromosomal translocations can occur while the chromosomes are being copied. This type of mutation can mean that an entire chromosome has moved to another location, or that a chromosome has broken, usually into two pieces, and moved to another site. Some translocations are harmless, but others can lead to aberrant cell proliferation and cancer.

“Over the last half century, chromosomal translocations encoding functional oncogenic proteins have been identified as drivers of multiple cancers, and account for 20% of all malignant neoplasms [1, 2].”

For example, the t(8;22)(p11;q11) chromosomal translocation leads to the initiation of an oncogenic fusion protein called the Breakpoint Cluster Region Fibroblast Growth Factor Receptor 1 (BCR-FGFR1). BCR-FGFR1 is a single driver of 8p11 myeloproliferative syndrome, which is also known as stem cell leukemia/lymphoma (SCLL).

“Stem cell leukemia/lymphoma (SCLL) exhibits distinct clinical and pathological features characterized by chromosomal translocations involving the FGFR1 gene at chromosome 8p11.”

In a trending new study, researchers from the University of California San Diego and Sanford Burnham Prebys Medical Discovery Institute examined mutations in PLCγ1 and Grb2 binding sites individually and when combined together in a double mutant within BCR-FGFR1. On May 11, 2022, the research paper was published in Oncotarget and entitled, “Proteomic analysis reveals dual requirement for Grb2 and PLCγ1 interactions for BCR-FGFR1-Driven 8p11 cell proliferation.”

The Study

In this study, the researchers used quantitative proteomic analyses to identify the crucial protein-to-protein interactions that may be necessary to activate BCR-FGFR1. The team used NIH3T3, HEK293T and 32D cells to assay five types of mutations: wild type BCR-FGFR1, a kinase-dead variant of BCR-FGFR1, a derivative of BCR-FGFR1 that contained a single mutation abolishing the Grb2 interaction site, a derivative of BCR-FGFR1 that contained a single mutation abolishing the PLCγ1 interaction site, and a double mutation that abolished both interaction sites (BCR(Y177F)-FGFR1(Y766F)).

“These data demonstrate that inhibition of either signaling pathway alone fails to inhibit hematopoietic cell proliferation, and demonstrate a dual requirement for Grb2 and PLCγ1 interactions with BCR-FGFR1 for proliferation.”

When either Grb2 or PLCγ1 signaling pathway was mutated, BCR-FGFR1 activity was decreased, but never abolished. However, when both Grb2 and PLCγ1 interactions were mutated, both cell transformation and proliferation were inhibited. The team demonstrated that BCR-FGFR1 dually relies on Grb2 and PLCγ1 for biological activity and the activation of cell signaling pathways. The researchers also found that the PLCγ1 inhibitor U73122 revealed that PLCγ1 is a potential therapeutic target for BCR-FGFR1-driven hematologic malignancies. In addition, the irreversible FGFR inhibitor futibatinib suppressed downstream signaling and cell transformation. 

“We demonstrate here that BCR-FGFR1 relies dually on the small adapter protein, Grb2, and the phospholipase, PLCγ1, for biological activity and the activation of cell signaling pathways (summarized in Figure 6).”

Figure 6: Signaling pathways activated by BCR-FGFR1.
Figure 6: Signaling pathways activated by BCR-FGFR1.

Conclusion

“Our work highlights the importance of sequencing based, mutation-specific therapies for FGFR1 induced hematologic malignancies.”

This study provides new insight into the potential molecular mechanisms underlying BCR-FGFR1 activity and identifies PLCγ1 as a therapeutic target for leukemia/lymphoma patients with this particular mutation. Future studies will be necessary to validate these findings in animal models and clinical trials. However, this study lays the groundwork for the development of new and more targeted leukemia/lymphoma therapies.

“These data unravel essential roles of Grb2 and PLCγ1 in BCR-FGFR1 mediated oncogenic growth and suggest the importance of further investigation into PLCγ1 as a potential therapeutic target in treating SCLL.”

Click here to read the full research paper published by Oncotarget.

ONCOTARGET VIDEOS: YouTube | LabTube | Oncotarget.com

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Oncotarget is an open-access journal that publishes primarily oncology-focused research papers in a continuous publishing format. These papers are available at no cost to readers on Oncotarget.com. Open-access journals have the power to benefit humanity from the inside out by rapidly disseminating information that may be freely shared with researchers, colleagues, family, and friends around the world.

For media inquiries, please contact media@impactjournals.com.

Oncotarget

Trending with Impact: RNA-Seq Analyses Show Targets in B-cell Lymphoma

January 14, 2021

“The current study is the first of its kind, wherein comprehensive transcriptome analysis using RNA-Seq was performed in Notch2 depleted B-cell lymphoma cells.”

Malignant effusion cytology: microscopic image of diffuse large B-cell lymphoma, a type of non Hodgkin lymphoma.
Malignant effusion cytology: microscopic image of diffuse large B-cell lymphoma, a type of non Hodgkin lymphoma.

The Trending with Impact series highlights Oncotarget publications attracting higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news and articles about the latest trending publications here, and at Oncotarget.com.

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Splenic marginal zone lymphoma (SMZL) is a rare subtype of non-Hodgkin lymphoma that comprises approximately 10% of all lymphoma cases. Marginal zone lymphomas (MZL) originate from B memory lymphocytes (B-cells) in the marginal zone of secondary lymphoid follicles within the spleen, bone marrow, and blood.

Due to the rarity of SMZL, no randomized trials have yet been reported—only retrospective studies and some prospective studies have been conducted. The irregularity of frequency and the indolent nature of this disease makes SMZL a challenge for doctors to determine a standardized care or treatment plan other than intervention by splenectomy.

Bringing with it great potential, researchers have found that a pivotal gene is mutated in SMZL: the Notch2 gene. The abnormal signaling and increased expression in Notch2 has been observed in a number of cancers, including MZL, chronic lymphocytic leukemia, breast cancer, non-small cell lung cancer, pancreatic cancer, hepatocellular carcinoma, colorectal cancer, bladder cancer, medulloblastoma, and glioblastoma.

“A wide range of Notch2 mutations have been identified with relevance to different cancers, but the role of Notch2 and its downstream pathways in development of B-cell lymphoma has not been comprehensively studied to date.”

Researchers from the School of Biotechnology and Genetic Engineering at Bharathiar University in Coimbatore, India, conducted a study of RNA sequencing analyses to reveal the differentially expressed genes and pathways as Notch2 targets in B-cell lymphoma.

Whole Transcriptome Analysis

The researchers in this study explain that transcriptome analysis and RNA sequencing (RNA-Seq) provided them the opportunity to deeply and unbiasedly screen for the molecular changes that occur in Notch2 deregulated B-cells and to identify the genes and pathways downstream from it as potential targets.

“RNA-Seq is a more sensitive technology than expression profiling analysis using arrays, due to their low sensitivity and cross-hybridization of probes and targets [34]. “

In order to deregulate, or knockdown, Notch2 expression, the researchers employed short, or small, hairpin RNAs (shRNAs). shRNAs are artificially created RNA molecules that can be used to silence target gene expression (Notch2, in this case) via RNA interference.

“To determine the efficacy of Notch2-shRNA in reducing the intracellular levels of Notch2, we treated A549 (lung cancer) and SSK-41 cells (B-cell lymphoma) with viral supernatants of two different shRNA constructs in a lentiviral vector targeting Notch2.” 

“The current study is the first of its kind, wherein comprehensive transcriptome analysis using RNA-Seq was performed in Notch2 depleted B-cell lymphoma cells.”

The Study

 “In the present study, whole transcriptome analysis was performed in B-cells, where Notch2 expression is knocked down using Notch2-shRNA and compared with control scramble-shRNA treated cells.”

In their first step, the researchers identified a total of 15,083 differentially expressed genes and 1067 differentially expressed transcripts in control and Notch2-shRNA treated samples. They used a condition tree, correlation matrix, and principal component analysis test to measure significant reproducibility, similarity, and distance between the treated and untreated group. 

In their second step, a gene enrichment analysis was performed in the differentially expressed genes using the DAVID tool. This resulted in the identification of 208 unique gene ontology (GO) categories and pathways.

Results

“Among the 208 GO categories, 31 pathways were significantly enriched in biological processes (BP), 3 pathways were significantly enriched in cellular components (CC) and 18 pathways were significantly enriched in molecular functions (MF).”

The researchers state that the significantly enriched terms they found could help with further understanding which differentially expressed genes and differentially expressed transcripts play causative roles in the onset of B-cell lymphoma.

“The RNA-Seq and bioinformatics technology revealed notable information regarding gene expression at the transcriptome level and identified multiple significant molecular pathways in response to knockdown of Notch2.”

Figure 9: Pathway analysis. Gene regulatory network analysis for DEGs upon Notch2 knockdown were predicted by Pathreg algorithm and visualized in Cytoscape v2.8.2. Predicted pathways are depicted as rounded rectangles, where shades in red correspond to upregulated genes and shades in green correspond to downregulated genes.
Figure 9: Pathway analysis. Gene regulatory network analysis for differentially expressed genes upon Notch2 knockdown were predicted by Pathreg algorithm and visualized in Cytoscape v2.8.2. Predicted pathways are depicted as rounded rectangles, where shades in red correspond to upregulated genes and shades in green correspond to downregulated genes.

“The results of our gene network analysis suggest that, knockdown of Notch2 modulates multiple important cellular pathways, including immune-related pathways, apoptotic related pathway, PI3K/AKT, BCR, mTOR, VEGF, Wnt and Ca2+ signaling pathways.”

Conclusion

The authors note that the NF-kB signaling pathway is a major pathway that leads to cell survival with the ability to “cross-talk” with other survival pathways, including PI3K/AKT, in various cancers.

“Since activation of PI3K/AKT pathway is known to promote cell proliferation, cell survival, growth and angiogenesis in cancers [40], it is important to know if Notch2 propels cancer progression through activation of this pathway. “

However, the researchers mention that the exact mechanism that Notch2 regulates NF-kB activity through the activation of PI3K/AKT and inhibits apoptosis in B-cell lymphoma still need to be determined. 

“Nevertheless, establishing the role of PI3K/AKT pathway in Notch2 activated cancers could be very important to consider it as an alternative treatment target in mitigating the effects of Notch2 transactivity in these cancers.” 

Click here to read the full study, published in Oncotarget.

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