Pretreatment of Glioblastoma with Bortezomib Potentiates Natural Killer Cell Cytotoxicity through TRAIL/DR5 Mediated Apoptosis and Prolongs Animal Survival

Bortezomib promotes the TRAIL-mediated killing of resistant rhabdomyosarcoma by ErbB2/Her2-targeted CAR-NK-92 cells via DR5 upregulation

Treatment resistance and immune escape are hallmarks of metastatic rhabdomyosarcoma (RMS), underscoring the urgent medical need for therapeutic agents against this disease entity as a key challenge in pediatric oncology. Chimeric antigen receptor (CAR)-based immunotherapies, such as the ErbB2 (Her2)-CAR-engineered natural killer (NK) cell line NK-92/5.28.z, provide antitumor cytotoxicity primarily through CAR-mediated cytotoxic granule release and thereafter-even in cases with low surface antigen expression or tumor escape-by triggering intrinsic NK cell-mediated apoptosis induction via additional ligand/receptors. In this study, we showed that bortezomib increased susceptibility toward apoptosis in clinically relevant RMS cell lines RH30 and RH41, and patient-derived RMS tumor organoid RMS335, by upregulation of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor DR5 in these metastatic, relapsed/refractory (r/r) RMS tumors. Subsequent administration of NK-92/5.28.z cells significantly enhanced antitumor activity in vitro. Applying recombinant TRAIL instead of NK-92/5.28.z cells confirmed that the synergistic antitumor effects of the combination treatment were mediated via TRAIL. Western blot analyses indicated that the combination treatment with bortezomib and NK-92/5.28.z cells increased apoptosis by interacting with the nuclear factor κB, JNK, and caspase pathways. Overall, bortezomib pretreatment can sensitize r/r RMS tumors to CAR- and, by upregulating DR5, TRAIL-mediated cytotoxicity of NK-92/5.28.z cells.

Proteasome Inhibitors against Glioblastoma-Overview of Molecular Mechanisms of Cytotoxicity, Progress in Clinical Trials, and Perspective for Use in Personalized Medicine

Proteasome inhibitors are moieties targeting the proteolytic activity of a proteasome, with demonstrated efficacy in certain hematological malignancies and candidate drugs in other types of cancer, including glioblastoma (GBM). They disturb the levels of proteasome-regulated proteins and lead to the cell cycle inhibition and apoptosis of GBM cells. The accumulation of cell cycle inhibitors p21 and p27, and decreased levels of prosurvival molecules NFKB, survivin, and MGMT, underlie proteasome inhibitors' cytotoxicity when used alone or in combination with the anti-GBM cytostatic drug temozolomide (TMZ). The evidence gathered in preclinical studies substantiated the design of clinical trials that employed the two most promising proteasome inhibitors, bortezomib and marizomib. The drug safety profile, maximum tolerated dose, and interaction with other drugs were initially evaluated, mainly in recurrent GBM patients. A phase III study on newly diagnosed GBM patients who received marizomib as an adjuvant to the Stupp protocol was designed and completed in 2021, with the Stupp protocol receiving patients as a parallel control arm. The data from this phase III study indicate that marizomib does not improve the PFS and OS of GBM patients; however, further analysis of the genetic and epigenetic background of each patient tumor may shed some light on the sensitivity of individual patients to proteasome inhibition. The mutational and epigenetic makeup of GBM cells, like genetic alterations to TP53 and PTEN, or MGMT promoter methylation levels may actually determine the response to proteasome inhibition.

Early TRAIL-engagement elicits potent multimodal targeting of melanoma by CD34+ progenitor cell-derived NK cells

Umbilical cord blood (UCB) CD34⁺ progenitor cell-derived natural killer (NK) cells exert efficient cytotoxicity against various melanoma cell lines. Of interest, the relative cytotoxic performance of individual UCB donors was consistent throughout the melanoma panel and correlated with IFNγ, TNF, perforin and granzyme B levels. Importantly, intrinsic perforin and Granzyme B load predicts NK cell cytotoxic capacity. Exploring the mode of action revealed involvement of the activating receptors NKG2D, DNAM-1, NKp30, NKp44, NKp46 and most importantly of TRAIL. Strikingly, combinatorial receptor blocking led to more pronounced inhibition of cytotoxicity (up to 95%) than individual receptor blocking, especially in combination with TRAIL-blocking, suggesting synergistic cytotoxic NK cell activity via engagement of multiple receptors which was also confirmed in a spheroid model. Importantly, lack of NK cell-related gene signature in metastatic melanomas correlates with poor survival highlighting the clinical significance of NK cell therapies as a promising treatment for high-risk melanoma patients.

Integrative profiling analysis reveals prognostic significance, molecular characteristics, and tumor immunity of angiogenesis-related genes in soft tissue sarcoma

Background

Soft tissue sarcoma (STS) is a class of malignant tumors originating from mesenchymal stroma with a poor prognosis. Accumulating evidence has proved that angiogenesis is an essential hallmark of tumors. Nevertheless, there is a paucity of comprehensive research exploring the association of angiogenesis-related genes (ARGs) with STS.

Methods

The ARGs were extracted from previous literature, and the differentially expressed ARGs were screened for subsequent analysis. Next, the least absolute shrinkage and selection operator (LASSO) and Cox regression analyses were conducted to establish the angiogenesis-related signature (ARSig). The predictive performance of the novel ARSig was confirmed using internal and external validation, subgroup survival, and independent analysis. Additionally, the association of the ARSig with the tumor immune microenvironment, tumor mutational burden (TMB), and therapeutic response in STS were further investigated. Notably, we finally conducted in vitro experiments to verify the findings from the bioinformatics analysis.

Results

A novel ARSig is successfully constructed and validated. The STS with a lower ARSig risk score in the training cohort has an improved prognosis. Also, consistent results were observed in the internal and external cohorts. The receiver operating characteristic (ROC) curve, subgroup survival, and independent analysis further indicate that the novel ARSig is a promising independent prognostic predictor for STS. Furthermore, it is proved that the novel ARSig is relevant to the immune landscape, TMB, immunotherapy, and chemotherapy sensitivity in STS. Encouragingly, we also validate that the signature ARGs are significantly dysregulated in STS, and ARDB2 and SRPK1 are closely connected with the malignant progress of STS cells.

Conclusion

In sum, we construct a novel ARSig for STS, which could act as a promising prognostic factor for STS and give a strategy for future clinical decisions, immune landscape, and personalized treatment of STS.

Cell-based and cell-free immunotherapies for glioblastoma: current status and future directions

Glioblastoma (GBM) is among the most fatal and recurring malignant solid tumors. It arises from the GBM stem cell population. Conventional neurosurgical resection, temozolomide (TMZ)-dependent chemotherapy and radiotherapy have rendered the prognosis of patients unsatisfactory. Radiotherapy and chemotherapy can frequently induce non-specific damage to healthy brain and other tissues, which can be extremely hazardous. There is therefore a pressing need for a more effective treatment strategy for GBM to complement or replace existing treatment options. Cell-based and cell-free immunotherapies are currently being investigated to develop new treatment modalities against cancer. These treatments have the potential to be both selective and successful in minimizing off-target collateral harm in the normal brain. In this review, several aspects of cell-based and cell-free immunotherapies related to GBM will be discussed.

Advances in NK cell therapy for brain tumors

Despite advances in treatment regimens that comprise surgery, chemotherapy, and radiation, outcome of many brain tumors remains dismal, more so when they recur. The proximity of brain tumors to delicate neural structures often precludes complete surgical resection. Toxicity and long-term side effects of systemic therapy remain a concern. Novel therapies are warranted. The field of NK cell-based cancer therapy has grown exponentially and currently constitutes a major area of immunotherapy innovation. This provides a new avenue for the treatment of cancerous lesions in the brain. In this review, we explore the mechanisms by which the brain tumor microenvironment suppresses NK cell mediated tumor control, and the methods being used to create NK cell products that subvert immune suppression. We discuss the pre-clinical studies evaluating NK cell-based immunotherapies that target several neuro-malignancies and highlight advances in molecular imaging of NK cells that allow monitoring of NK cell-based therapeutics. We review current and ongoing NK cell based clinical trials in neuro-oncology.

Expanded natural killer cells potentiate the antimyeloma activity of daratumumab, lenalidomide, and dexamethasone in a myeloma xenograft model

The development of new treatment agents in recent decades has significantly improved the survival of patients with multiple myeloma (MM). Nonetheless, MM remains an incurable disease; therefore, novel combination therapies are required. Natural killer (NK) cells are one of the safest immunotherapeutic options. In this study, we found that the anti-myeloma activity of expanded NK cells (eNKs) was improved by daratumumab, lenalidomide, and dexamethasone (DRd) in an MM xenograft mouse model. NK cells expanded from peripheral blood mononuclear cells collected from MM patients were highly cytotoxic against DRd pretreated tumor cells in vitro. To mimic the clinical protocol, a human MM xenograft model was developed using human RPMI8226-RFP-FLuc cells in NOD/SCID IL-2Rγnull (NSG) mice. MM bearing mice were randomly divided into six groups: no treatment, eNK, Rd, Rd + eNKs, DRd, and DRd + eNKs. DRd significantly enhanced the cytotoxicity of eNKs by upregulating NK cell activation ligands and effector function. DRd in combination with eNKs significantly reduced the serum M-protein level and prolonged mouse survival. In addition, DRd significantly increased the persistence of eNK and homing to MM sites. These results show that the anti-myeloma activity of ex vivo-expanded and activated NK cells is augmented by the immunomodulatory effect of DRd in MM-bearing mice, suggesting the therapeutic potential of this combination for MM patients.

Advanced Cell Therapies for Glioblastoma

The sheer ubiquity of Gioblastoma (GBM) cases would lead you to believe that there should have been many opportunities for the discovery of treatments to successfully render it into remission. Unfortunately, its persistent commonality is due in large part to the fact that it is the most treatment-resistant tumors in adults. That completely changes the treatment plan of attack. Long established and accepted treatment therapies such as surgical resection, radiation, and aggressive chemotherapy, (and any combination thereof) have only confirmed that the disease lives up to its treatment-resistant reputation. To add to the seemingly insurmountable task of finding a cure, GBM has also proven to be a very stubborn and formidable opponent to newer immunotherapies. Across the board, regardless of the therapy combination, the five-year survival rate of GBM patients is still very poor at a heartbreaking 5.6%. Obviously, the present situation cannot be tolerated or deemed acceptable. The grave situation calls for researchers to be more innovative and find more efficient strategies to discover new and successful strategies to treat GBM. Inspired by researchers worldwide attempting to control GBM, we provide in this review a comprehensive overview of the many diverse cell therapies currently being used to treat GBM. An overview of the treatments include: CAR T cells, CAR NK cells, gamma-delta T cells, NKT cells, dendritic cells, macrophages, as well stem cell-based strategies. To give you the complete picture, we will discuss the efficacy, safety, and developmental stages, the mechanisms of action and the challenges of each of these therapies and detail their potential to be the next-generation immunotherapeutic to eliminate this dreadful disease.

Harnessing natural killer cells for cancer immunotherapy: dispatching the first responders

Natural killer (NK) cells have crucial roles in the innate immunosurveillance of cancer and viral infections. They are 'first responders' that can spontaneously recognize abnormal cells in the body, rapidly eliminate them through focused cytotoxicity mechanisms and potently produce pro-inflammatory cytokines and chemokines that recruit and activate other immune cells to initiate an adaptive response. From the initial discovery of the diverse cell surface receptors on NK cells to the characterization of regulatory events that control their function, our understanding of the basic biology of NK cells has improved dramatically in the past three decades. This advanced knowledge has revealed increased mechanistic complexity, which has opened the doors to the development of a plethora of exciting new therapeutics that can effectively manipulate and target NK cell functional responses, particularly in cancer patients. Here, we summarize the basic mechanisms that regulate NK cell biology, review a wide variety of drugs, cytokines and antibodies currently being developed and used to stimulate NK cell responses, and outline evolving NK cell adoptive transfer approaches to treat cancer.

NK cells in the brain: implications for brain tumor development and therapy

Natural killer (NK) cells are innate lymphoid cells with robust antitumor functions rendering them promising therapeutic tools against malignancies. Despite constituting a minor fraction of the immune cells infiltrating tumors in the brain, insights into their role in central nervous system (CNS) pathophysiology are emerging. The challenges posed by a profoundly immunosuppressive microenvironment as well as by tumor resistance mechanisms necessitate exploring avenues to enhance the therapeutic potential of NK cells in both primary and metastatic brain malignancies. In this review, we summarize the role of NK cells in the pathogenesis of tumors in the brain and discuss the avenues investigated to harness their anticancer effects against primary and metastatic CNS tumors, including sources of therapeutic NK cells, combinations with other treatments, and novel engineering approaches for augmenting their cytotoxicity. We also highlight relevant preclinical evidence and clinical trials of NK cell-based therapies.

The War Is on: The Immune System against Glioblastoma—How Can NK Cells Drive This Battle?

Natural killer (NK) cells are innate lymphocytes that play an important role in immunosurveillance, acting alongside other immune cells in the response against various types of malignant tumors and the prevention of metastasis. Since their discovery in the 1970s, they have been thoroughly studied for their capacity to kill neoplastic cells without the need for previous sensitization, executing rapid and robust cytotoxic activity, but also helper functions. In agreement with this, NK cells are being exploited in many ways to treat cancer. The broad arsenal of NK-based therapies includes adoptive transfer of in vitro expanded and activated cells, genetically engineered cells to contain chimeric antigen receptors (CAR-NKs), in vivo stimulation of NK cells (by cytokine therapy, checkpoint blockade therapies, etc.), and tumor-specific antibody-guided NK cells, among others. In this article, we review pivotal aspects of NK cells’ biology and their contribution to immune responses against tumors, as well as providing a wide perspective on the many antineoplastic strategies using NK cells. Finally, we also discuss those approaches that have the potential to control glioblastoma—a disease that, currently, causes inevitable death, usually in a short time after diagnosis.

Ferroptosis Activation Scoring Model Assists in Chemotherapeutic Agents’ Selection and Mediates Cross-Talk With Immunocytes in Malignant Glioblastoma

Gliomas are aggressive tumors in the central nervous system and glioblastoma is the most malignant type. Ferroptosis is a programmed cell death that can modulate tumor resistance to therapy and the components of tumor microenvironment. However, the relationship between ferroptosis, tumor immune landscape, and glioblastoma progression is still elusive. In this work, data from bulk RNA-seq analysis, single cell RNA-seq analysis, and our own data (the Xiangya cohort) are integrated to reveal their relationships. A scoring system is constructed according to ferroptosis related gene expression, and high scoring samples resistant to ferroptosis and show worse survival outcome than low scoring samples. Notably, most of the high scoring samples are aggressive glioblastoma subtype, mesenchymal, and classical, by calculating RNA velocity. Cross-talk between high scoring glioblastoma cells and immunocytes are explored by R package ‘celltalker’. Ligand–receptor pairs like the TRAIL or TWEAK signaling pathway are identified as novel bridges implying how ferroptosis modulate immunocytes’ function and shape tumor microenvironment. Critically, potential drugs target to high scoring samples are predicted, namely, SNX2112, AZ628, and bortezomib and five compounds from the CellMiner database. Taken together, ferroptosis associates with glioblastoma aggressiveness, cross-talk with immunocytes and offer novel chemotherapy strategy.

The multifaceted mechanisms of malignant glioblastoma progression and clinical implications

With the application of high throughput sequencing technologies at single-cell resolution, studies of the tumor microenvironment in glioblastoma, one of the most aggressive and invasive of all cancers, have revealed immense cellular and tissue heterogeneity. A unique extracellular scaffold system adapts to and supports progressive infiltration and migration of tumor cells, which is characterized by altered composition, effector delivery, and mechanical properties. The spatiotemporal interactions between malignant and immune cells generate an immunosuppressive microenvironment, contributing to the failure of effective anti-tumor immune attack. Among the heterogeneous tumor cell subpopulations of glioblastoma, glioma stem cells (GSCs), which exhibit tumorigenic properties and strong invasive capacity, are critical for tumor growth and are believed to contribute to therapeutic resistance and tumor recurrence. Here we discuss the role of extracellular matrix and immune cell populations, major components of the tumor ecosystem in glioblastoma, as well as signaling pathways that regulate GSC maintenance and invasion. We also highlight emerging advances in therapeutic targeting of these components.

Cell-Based Therapy for the Treatment of Glioblastoma: An Update from Preclinical to Clinical Studies

Glioblastoma (GB), an aggressive primary tumor of the central nervous system, represents about 60% of all adult primary brain tumors. It is notorious for its extremely low (~5%) 5-year survival rate which signals the unsatisfactory results of the standard protocol for GB therapy. This issue has become, over time, the impetus for the discipline of bringing novel therapeutics to the surface and challenging them so they can be improved. The cell-based approach in treating GB found its way to clinical trials thanks to a marvelous number of preclinical studies that probed various types of cells aiming to combat GB and increase the survival rate. In this review, we aimed to summarize and discuss the up-to-date preclinical studies that utilized stem cells or immune cells to treat GB. Likewise, we tried to summarize the most recent clinical trials using both cell categories to treat or prevent recurrence of GB in patients. As with any other therapeutics, cell-based therapy in GB is still hampered by many drawbacks. Therefore, we highlighted several novel techniques, such as the use of biomaterials, scaffolds, nanoparticles, or cells in the 3D context that may depict a promising future when combined with the cell-based approach.

Synergistic Tumor Cytolysis by NK Cells in Combination With a Pan-HDAC Inhibitor, Panobinostat

Histone deacetylases (HDAC) are frequently overexpressed in tumors, and their inhibition has shown promising anti-tumor effects. However, the synergistic effects of HDAC inhibition with immune cell therapy have not been fully explored. Natural killer (NK) cells are cytotoxic lymphocytes for anti-tumor immune surveillance, with immunotherapy potential. We showed that a pan-HDAC inhibitor, panobinostat, alone demonstrated anti-tumor and anti-proliferative activities on all tested tumors in vitro. Additionally, panobinostat co-treatment or pretreatment synergized with NK cells to mediate tumor cell cytolysis. Mechanistically, panobinostat treatment increased the expression of cell adhesion and tight junction-related genes, promoted conjugation formation between NK and tumor cells, and modulates NK cell-activating receptors and ligands on tumor cells, contributing to the increased tumor cytolysis. Finally, panobinostat therapy led to better tumor control and synergized with anti-PD-L1 therapy. Our data highlights the anti-tumor potential of HDAC inhibition through tumor-intrinsic toxicity and enhancement of NK -based immunotherapy.

Effectiveness of bortezomib and temozolomide for eradication of recurrent human glioblastoma cells, resistant to radiation

BACKGROUND

Glioblastoma multiforme (GBM) is a primary human brain tumor with the highest mortality rate. The prognosis for such patients is unfavorable, since the tumor is highly resistant to treatment, and the median survival of patients is 13 months. Chemotherapy might extend patients' life, but a tumor, that reappears after chemoradiotherapy, is resistant to temozolomide (TMZ). Using postgenome technologies in clinical practice might have a positive effect on the treatment of a recurrent GBM.

METHODS

T98G cells of human GBM have been used. Radiation treatment was performed with Rokus-M gamma-therapeutic system, using ⁶⁰Сo as a source of radionuclide emissions. High-performance liquid chromatography-mass spectrometry was used for proteome analysis. Mass spectrometry data were processed with MaxQuant (version 1.6.1.0) and Perseus (version 1.6.1) software, Max Planck Institute of Biochemistry (Germany). Biological processes, molecular functions, cells locations and protein pathways were annotated with a help of PubMed, PANTHER, Gene Ontology and KEGG and STRING v10 databases. Pharmaceutical testing was performed in vitro with a panel of traditional chemotherapeutic agents.

RESULTS

GBM cells proliferation speed is inversely proportional to the irradiation dose and recedes when the dosage is increased, as expected. Synthesis of ERC1, NARG1L, PLCD3, ROCK2, SARNP, TMSB4X and YTHDF2 in GBM cells, treated with 60Gy of radiation, shows more than a fourfold increase, while the synthesis level of PSMA2, PSMA3, PSMA4, PSMB2, PSMB3, PSMB7, PSMC3, PSMD1, PSMD3 proteins increases significantly. Traditional chemotherapeutic agents are not very effective against cancer cells of the recurrent GBM. Combination of TMZ and CCNU with a proteasome inhibitor-bortezomib-significantly increases their ability to eradicate cells of a radioresistant GBM.

CONCLUSIONS

Bortezomib and temozolomide effectively destroy cells of a radioresistant recurrent human glioblastoma; proteome mapping of the recurrent GBM cancer cells allows to identify new targets for therapy to improve the treatment results.

Expanded natural killer cells augment the antimyeloma effect of daratumumab, bortezomib, and dexamethasone in a mouse model

The use of natural killer (NK) cells is a promising and safe immunotherapeutic approach in the field of cancer immunotherapy. However, combination treatments are required to enhance the effector functions and therapeutic efficacy of NK cells. In this study, we investigated the potential of daratumumab (Dara), bortezomib, and dexamethasone (Dvd) to augment the antitumor effects of NK cells in a multiple myeloma (MM) xenograft mouse model. NK cells were expanded and activated using the K562-OX40 ligand and membrane-bound IL-18 and IL-21 in the presence of IL-2 and IL-15 from peripheral blood mononuclear cells from MM patients. A human MM xenograft model was established using human RPMI8226-RFP-FLuc cells in NOD/SCID IL-2Rγ^null (NSG) mice. Tumor-bearing mice were divided into six treatment groups: no treatment, expanded NK cells (eNKs), Dara, Dara + eNKs, Dvd, and Dvd + eNKs. Dvd treatment strongly enhanced the cytotoxicity of eNKs by upregulating expression of NK cell activation ligands, downregulating expression of NK cell inhibitory ligands, and promoting antibody-dependent cellular cytotoxicity. The combination of eNKs with Dvd significantly prolonged mouse survival and reduced the tumor burden and serum M-protein level. Furthermore, Dvd pretreatment significantly increased eNK persistence and homing to MM sites. Our findings suggest that Dvd treatment potentiates the antimyeloma effects of NK cells expanded and activated ex vivo by modulating immune responses in MM-bearing mice.

Overcoming TRAIL Resistance for Glioblastoma Treatment

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) shows a promising therapeutic potential in cancer treatment as it exclusively causes apoptosis in a broad spectrum of cancer cells through triggering the extrinsic apoptosis pathway via binding to cognate death receptors, with negligible toxicity in normal cells. However, most cancers, including glioblastoma multiforme (GBM), display TRAIL resistance, hindering its application in clinical practice. Recent studies have unraveled novel mechanisms in regulating TRAIL-induced apoptosis in GBM and sought effective combinatorial modalities to sensitize GBM to TRAIL treatment, establishing pre-clinical foundations and the reasonable expectation that the TRAIL/TRAIL death receptor axis could be harnessed to treat GBM. In this review, we will revisit the status quo of the mechanisms of TRAIL resistance and emerging strategies for sensitizing GBM to TRAIL-induced apoptosis and also discuss opportunities of TRAIL-based combinatorial therapies in future clinical use for GBM treatment.

Natural Killer cells and monoclonal antibodies: Two partners for successful antibody dependent cytotoxicity against tumor cells

Monoclonal antibodies targeting tumors are one of the most important discoveries in the field of cancer. Although several effective antibodies have been developed, a relapse may occur. One of their mechanisms of action is Antibody Dependent Cell Cytotoxicity (ADCC), by engaging the Fc γ receptor CD16 expressing Natural Killer cells, innate lymphoid cells involved in cancer immunosurveillance and able to kill tumor cells. A lack of NK cells observed in many cancers may therefore be a cause of the low efficacy of antibodies observed in some clinical situations. Here we review clear evidences of the essential partnership between NK cells and antibodies showed in vitro, in vivo, and in clinical trials in different indications, describe the hurdles and ways to enhance ADCC and the evolution of monoclonal antibody therapy. NK cell adoptive immunotherapy combined with monoclonal antibodies may overcome the resistance to the treatment and enhance their efficacy.

The Role of NK Cells and Innate Lymphoid Cells in Brain Cancer

The brain is considered an immune privileged site due to the high selectivity of the blood-brain barrier which restricts the passage of molecules and cells into the brain parenchyma. Recent studies have highlighted active immunosurveillance mechanisms in the brain. Here we review emerging evidence for the contribution of innate lymphoid cells (ILCs) including natural killer (NK) cells to the immunosurveillance of brain cancers focusing on glioblastoma, one of the most aggressive and most common malignant primary brain tumors diagnosed in adults. Moreover, we discuss how the local tissue microenvironment and unique cellular interactions influence ILC functions in the brain and how these interactions might be successfully harnessed for cancer immunotherapy using insights gained from the studies of autoimmunity, aging, and CNS injury.

Repositioning Quinacrine Toward Treatment of Ovarian Cancer by Rational Combination With TRAIL

Quinacrine has been identified as a potent DR5-inducing agent that sensitizes cancer cells to TRAIL-induced apoptosis. In the current study, we found that quinacrine increased DR5 mRNA levels significantly in ovarian cancer cell lines regardless of p53 status. Further study showed the half-life of DR5 in quinacrine-treated cells was significantly prolonged, indicating that DR5 protein degradation was inhibited by quinacrine. We tested if the combination of TRAIL and quinacrine could be effective in ovarian cancer treatment in vitro and in ovarian cancer xenograft mouse models. We found that quinacrine enhanced TRAIL sensitivity or reversed TRAIL resistance in all the ovarian cancer cell lines tested. Mice treated with quinacrine and TRAIL remained disease-free for up to 20 weeks, however, mice treated with TRAIL or quinacrine alone and in control group died within ~8 weeks after treatment. Intraperitoneal delivery of quinacrine and TRAIL is rational and practical with extraordinary synergistic anti-cancer effects in preclinical models of ovarian cancer. Clinical investigation of combining quinacrine with TRAIL for ovarian cancer treatment is warranted.

Exploring the RC-106 Chemical Space: Design and Synthesis of Novel (E)-1-(3-Arylbut-2-en-1-yl)-4-(Substituted) Piperazine Derivatives as Potential Anticancer Agents

Despite the fact that significant advances in treatment of common cancers have been achieved over the years, orphan tumors still represent an important unmet medical need. Due to their complex multifactorial origin and limited number of cases, such pathologies often have very limited treatment options and poor prognosis. In the search for new anticancer agents, our group recently identified RC-106, a Sigma receptor modulator endowed with proteasome inhibition activity. This compound showed antiproliferative activity toward different cancer cell lines, among them glioblastoma (GB) and multiple myeloma (MM), two currently unmet medical conditions. In this work, we directed our efforts toward the exploration of chemical space around RC-106 to identify new active compounds potentially useful in cancer treatment. Thanks to a combinatorial approach, we prepared 41 derivatives of the compound and evaluated their cytotoxic potential against MM and GB. Three novel potential anticancer agents have been identified.

Sequential bortezomib and temozolomide treatment promotes immunological responses in glioblastoma patients with positive clinical outcomes: A phase 1B study

BACKGROUND

Glioblastoma (GBM) is an aggressive malignant brain tumor where median survival is approximately 15 months after best available multimodal treatment. Recurrence is inevitable, largely due to O⁶ methylguanine DNA methyltransferase (MGMT) that renders the tumors resistant to temozolomide (TMZ). We hypothesized that pretreatment with bortezomib (BTZ) 48 hours prior to TMZ to deplete MGMT levels would be safe and tolerated by patients with recurrent GBM harboring unmethylated MGMT promoter. The secondary objective was to investigate whether 26S proteasome blockade may enhance differentiation of cytotoxic immune subsets to impact treatment responses measured by radiological criteria and clinical outcomes.

METHODS

Ten patients received intravenous BTZ 1.3 mg/m² on days 1, 4, and 7 during each 4th weekly TMZ-chemotherapy starting on day 3 and escalated from 150 mg/m² per oral 5 days/wk via 175 to 200 mg/m² in cycles 1, 2, and 3, respectively. Adverse events and quality of life were evaluated by CTCAE and EQ-5D-5L questionnaire, and immunological biomarkers evaluated by flow cytometry and Luminex enzyme-linked immunosorbent assay.

RESULTS

Sequential BTZ + TMZ therapy was safe and well tolerated. Pain and performance of daily activities had greatest impact on patients' self-reported quality of life and were inversely correlated with Karnofsky performance status. Patients segregated a priori into three groups, where group 1 displayed stable clinical symptoms and/or slower magnetic resonance imaging radiological progression, expanded CD4⁺ effector T-cells that attenuated cytotoxic T-lymphocyte associated protein-4 and PD-1 expression and secreted interferon γ and tumor necrosis factor α in situ and ex vivo upon stimulation with PMA/ionomycin. In contrast, rapidly progressing group 2 patients exhibited tolerised T-cell phenotypes characterized by fourfold to sixfold higher interleukin 4 (IL-4) and IL-10 Th-2 cytokines after BTZ + TMZ treatment, where group 3 patients exhibited intermediate clinical/radiological responses.

CONCLUSION

Sequential BTZ + TMZ treatment is safe and promotes Th1-driven immunological responses in selected patients with improved clinical outcomes (Clinicaltrial.gov (NCT03643549)).

Inhibition of PLK4 might enhance the anti-tumour effect of bortezomib on glioblastoma via PTEN/PI3K/AKT/mTOR signalling pathway

Glioblastoma (GBM) is one of the most common aggressive cancers of the central nervous system in adults with a high mortality rate. Bortezomib is a boronic acid-based potent proteasome inhibitor that has been actively studied for its anti-tumour effects through inhibition of the proteasome. The proteasome is a key component of the ubiquitin-proteasome pathway that is critical for protein homeostasis, regulation of cellular growth, and apoptosis. Overexpression of polo-like kinase 4 (PLK4) is commonly reported in tumour cells and increases their invasive and metastatic abilities. In this study, we established a cell model of PLK4 knockdown and overexpression in LN-18, A172 and LN-229 cells and found that knockdown of PLK4 expression enhanced the anti-tumour effect of bortezomib. We further found that this effect may be mediated by the PTEN/PI3K/AKT/mTOR signalling pathway and that the apoptotic and oxidative stress processes were activated, while the expression of matrix metalloproteinases (MMPs) was down-regulated. Similar phenomenon was observed using in vitro experiments. Thus, we speculate that PLK4 inhibition may be a new therapeutic strategy for GBM.

CAR-Engineered NK Cells for the Treatment of Glioblastoma: Turning Innate Effectors Into Precision Tools for Cancer Immunotherapy

Glioblastoma (GB) is the most common and aggressive primary brain tumor in adults and currently incurable. Despite multimodal treatment regimens, median survival in unselected patient cohorts is <1 year, and recurrence remains almost inevitable. Escape from immune surveillance is thought to contribute to the development and progression of GB. While GB tumors are frequently infiltrated by natural killer (NK) cells, these are actively suppressed by the GB cells and the GB tumor microenvironment. Nevertheless, ex vivo activation with cytokines can restore cytolytic activity of NK cells against GB, indicating that NK cells have potential for adoptive immunotherapy of GB if potent cytotoxicity can be maintained in vivo. NK cells contribute to cancer immune surveillance not only by their direct natural cytotoxicity which is triggered rapidly upon stimulation through germline-encoded cell surface receptors, but also by modulating T-cell mediated antitumor immune responses through maintaining the quality of dendritic cells and enhancing the presentation of tumor antigens. Furthermore, similar to T cells, specific recognition and elimination of cancer cells by NK cells can be markedly enhanced through expression of chimeric antigen receptors (CARs), which provides an opportunity to generate NK-cell therapeutics of defined specificity for cancer immunotherapy. Here, we discuss effects of the GB tumor microenvironment on NK-cell functionality, summarize early treatment attempts with ex vivo activated NK cells, and describe relevant CAR target antigens validated with CAR-T cells. We then outline preclinical approaches that employ CAR-NK cells for GB immunotherapy, and give an overview on the ongoing clinical development of ErbB2 (HER2)-specific CAR-NK cells currently applied in a phase I clinical trial in glioblastoma patients.