Correlation of immune fitness with response to teclistamab in relapsed/refractory multiple myeloma in MajesTEC-1

Teclistamab, an off-the-shelf B-cell maturation antigen (BCMA) × CD3 bispecific antibody that mediates T-cell activation and subsequent lysis of BCMA-expressing myeloma cells, is approved for the treatment of patients with relapsed/refractory multiple myeloma (RRMM). As a T-cell redirection therapy, clinical outcomes with teclistamab may be influenced by patient immune fitness and tumor antigen expression. We correlated tumor characteristics and baseline immune profiles with clinical response and disease burden in patients with RRMM from the pivotal phase 1/2 MajesTEC-1 study, focusing on patients treated with 1.5 mg/kg of teclistamab (N = 165). Peripheral blood samples were collected at screening and bone marrow samples were collected at screening and cycle 3. Better clinical outcomes to teclistamab correlated with higher baseline total T-cell counts in the periphery. In addition, responders (partial response or better) had a lower proportion of immunosuppressive regulatory T cells, T cells expressing co-inhibitory receptors (CD38, PD-1, PD-1/TIM-3), and soluble BCMA, and a T-cell profile suggestive of a more cytolytic potential, compared with nonresponders. Neither frequency of baseline bone marrow BCMA expression nor BCMA receptor density were associated with clinical response to teclistamab. Improved progression-free survival was observed in patients with a lower frequency of T cells expressing exhaustion markers and immunosuppressive regulatory T cells. Overall, response to teclistamab was associated with baseline immune fitness; nonresponders had immune profiles suggestive of immune suppression and T-cell dysfunction. These findings illustrate the importance of the contribution of the immune landscape to T-cell redirection therapy response. This trial was registered at www.ClinicalTrials.gov, NCT03145181/NCT04557098.

GPRC5D as a novel target for the treatment of multiple myeloma: a narrative review

Multiple myeloma is a genetically complex and heterogenous malignancy with a 5-year survival rate of approximately 60%. Despite advances in therapy, patients experience cycles of remission and relapse, with each successive line of therapy associated with poorer outcomes; therefore, therapies with different mechanisms of action against new myeloma antigens are needed. G protein-coupled receptor class C group 5 member D (GPRC5D) has emerged as a novel therapeutic target for the treatment of multiple myeloma. We review the biology and target validation of GPRC5D, and clinical data from early phase trials of GPRC5D-targeting bispecific antibodies, talquetamab and forimtamig, and chimeric antigen receptor T cell (CAR-T) therapies, MCARH109, OriCAR-017, and BMS-986393. In addition to adverse events (AEs) associated with T-cell-redirection therapies irrespective of target, a consistent pattern of dermatologic and oral AEs has been reported across several trials of GPRC5D-targeting bispecific antibodies, as well as rare cerebellar events with CAR-T therapy. Additional studies are needed to understand the underlying mechanisms involved in the development of skin- and oral-related toxicities. We review the strategies that have been used to manage these GPRC5D-related toxicities. Preliminary efficacy data showed overall response rates for GPRC5D-targeting T-cell-redirecting therapies were ≥64%; most responders achieved a very good partial response or better. Pharmacokinetics/pharmacodynamics showed that these therapies led to cytokine release and T-cell activation. In conclusion, results from early phase trials of GPRC5D-targeting T-cell-redirecting agents have shown promising efficacy and manageable safety profiles, including lower infection rates compared with B-cell maturation antigen- and Fc receptor-like protein 5-targeting bispecific antibodies. Further clinical trials, including those investigating GPRC5D-targeting T-cell-redirecting agents in combination with other anti-myeloma therapies and with different treatment modalities, may help to elucidate the future optimal treatment regimen and sequence for patients with multiple myeloma and improve survival outcomes. Video Summary.

Teclistamab impairs humoral immunity in patients with heavily pretreated myeloma: importance of immunoglobulin supplementation

ABSTRACT

Teclistamab and other B-cell maturation antigen (BCMA)-targeting bispecific antibodies (BsAbs) have substantial activity in patients with heavily pretreated multiple myeloma (MM) but are associated with a high rate of infections. BCMA is also expressed on normal plasma cells and mature B cells, which are essential for the generation of a humoral immune response. The aim of this study was to improve the understanding of the impact of BCMA-targeting BsAbs on humoral immunity. The impact of teclistamab on polyclonal immunoglobulins and B cell counts was evaluated in patients with MM who received once-weekly teclistamab 1.5 mg/kg subcutaneously. Vaccination responses were assessed in a subset of patients. Teclistamabinduced rapid depletion of peripheral blood B cells in patients with MM and eliminated normal plasma cells in ex vivo assays. In addition, teclistamab reduced the levels of polyclonal immunoglobulins (immunoglobulin G [IgG], IgA, IgE, and IgM), without recovery over time while receiving teclistamab therapy. Furthermore, response to vaccines against Streptococcus pneumoniae, Haemophilus influenzae type B, and severe acute respiratory syndrome coronavirus 2 was severely impaired in patients treated with teclistamab compared with vaccination responses observed in patients with newly diagnosed MM or relapsed/refractory MM. Intravenous immunoglobulin (IVIG) use was associated with a significantly lower risk of serious infections among patients treated with teclistamab (cumulative incidence of infections at 6 months: 5.3% with IVIG vs 54.8% with observation only [P < .001]). In conclusion, our data show severe defects in humoral immunity induced by teclistamab, the impact of which can be mitigated by the use of immunoglobulin supplementation. This trial was registered at www.ClinicalTrials.gov as #NCT04557098.

Blockade of growth hormone receptor signaling by using pegvisomant: A functional therapeutic strategy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive neoplasm with poor clinical outcome because most patients present at an advanced stage, at which point curative surgical options, such as tumor excision or liver transplantation, are not feasible. Therefore, the majority of HCC patients require systemic therapy. Nonetheless, the currently approved systemic therapies have limited effects, particularly in patients with advanced and resistant disease. Hence, there is a critical need to identify new molecular targets and effective systemic therapies to improve HCC outcome. The liver is a major target of the growth hormone receptor (GHR) signaling, and accumulating evidence suggests that GHR signaling plays an important role in HCC pathogenesis. We tested the hypothesis that GHR could represent a potential therapeutic target in this aggressive neoplasm. We measured GH levels in 767 HCC patients and 200 healthy controls, and then carried out clinicopathological correlation analyses. Moreover, specific inhibition of GHR was performed in vitro using siRNA and pegvisomant (a small peptide that blocks GHR signaling and is currently approved by the FDA to treat acromegaly) and in vivo, also using pegvisomant. GH was significantly elevated in 49.5% of HCC patients, and these patients had a more aggressive disease and poorer clinical outcome (P<0.0001). Blockade of GHR signaling with siRNA or pegvisomant induced substantial inhibitory cellular effects in vitro. In addition, pegvisomant potentiated the effects of sorafenib (P<0.01) and overcame sorafenib resistance (P<0.0001) in vivo. Mechanistically, pegvisomant decreased the phosphorylation of GHR downstream survival proteins including JAK2, STAT3, STAT5, IRS-1, AKT, ERK, and IGF-IR. In two patients with advanced-stage HCC and high GH who developed sorafenib resistance, pegvisomant caused tumor stability. Our data show that GHR signaling represents a novel “druggable” target, and pegvisomant may function as an effective systemic therapy in HCC. Our findings could also lead to testing GHR inhibition in other aggressive cancers.

A novel, immunotherapy-based approach for the treatment of relapsed/refractory multiple myeloma (RRMM): Updated phase 1b results for daratumumab in combination with teclistamab (a BCMA x CD3 bispecific antibody)

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Background: Teclistamab (tec; JNJ-64007957) is a BCMA × CD3 T-cell redirecting bispecific antibody under investigation in patients (pts) with RRMM. Daratumumab (dara) is a CD38 mAb with direct on-tumor and immunomodulatory actions. Initial clinical data from the phase 1b multicohort TRIMM-2 study support the combination of tec + dara for the treatment of RRMM, with tolerable safety, no overlapping toxicities, and promising efficacy. We present updated results with additional pts and longer follow-up. Methods: Eligible MM pts aged ≥18 y had received ≥3 prior lines of therapy (LOT; including a proteosome inhibitor [PI] and immunomodulatory drug [IMiD]) or were double-refractory to a PI and IMiD. Pts treated with anti-CD38 therapy ≤90 d prior were excluded. Pts received dara SC 1800 mg per approved schedule and tec SC 1.5–3 mg/kg QW or Q2W. Primary objectives were to identify the recommended phase 2 dose of tec for combination therapy and evaluate safety of the combination. Responses were assessed by IMWG criteria. AEs were graded per CTCAE v5.0; cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) were graded per ASTCT guidelines. Results: At data cutoff (Jan 13, 2022; safety population: N=46), median follow-up was 7.2 mo (range 0.1–16.6; median age 67 y [range 50–79]; 52% female). Pts received a median of 6 prior LOT (range 2–17; 74% triple-class exposed; 63% penta-drug exposed; 15% anti-BCMA exposed). 91% of pts had ≥1 AE (grade 3/4 78%), most commonly CRS (61%; all grade 1/2; median time to onset 2 d; median duration 2 d), neutropenia (54%; grade 3/4 50%), anemia (46%; grade 3/4 28%), thrombocytopenia (33%; grade 3/4 28%), and diarrhea (33%; grade 3/4 2%). Infections occurred in 29 pts (63%; grade 3/4 28%). One pt had grade 1 ICANS that fully resolved. Among 37 response-evaluable pts, ORR was 78% (29/37); 27 pts (73%) had very good partial response (VGPR) or better (Table). Median time to first response across dosing cohorts was 1.0 mo (range 0.9–2.8); median duration of response was not reached. Upregulation of CD38+/CD8+ T cells and proinflammatory cytokines was observed with tec + dara, supporting potential synergy of the combination in pts with prior anti-CD38 exposure. Updated results will be presented. Conclusions: Tec + dara provides a novel immunotherapy approach for the treatment of RRMM that may yield improved clinical efficacy in heavily pretreated pts. Clinical trial information: NCT04108195. [Table: see text]

Efficacy and safety of talquetamab, a G protein-coupled receptor family C group 5 member D x CD3 bispecific antibody, in patients with relapsed/refractory multiple myeloma (RRMM): Updated results from MonumenTAL-1

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Background: G protein-coupled receptor family C group 5 member D (GPRC5D), which has limited expression in normal human tissue but is highly expressed on malignant plasma cells, is a promising target for multiple myeloma (MM) immunotherapy. Talquetamab (JNJ-64407564) is a first-in-class, bispecific IgG4 antibody that binds to both GPRC5D and CD3 receptors, mediating T-cell–activated lysis of GPRC5D+ MM cells. Here we report updated results with additional patients (pts) and longer follow-up from MonumenTAL-1, a phase 1 trial of talquetamab in RRMM (NCT03399799). Methods: Eligible pts had RRMM or were intolerant to standard therapies; prior B-cell maturation antigen-directed therapies were permitted. The primary objectives were to identify the recommended phase 2 doses (RP2Ds) (part 1) and assess talquetamab safety and tolerability at the RP2Ds (part 2). Collective safety, efficacy, PK, and PD data supported 2 RP2Ds for talquetamab: 405 μg/kg SC QW (n = 30) and 800 μg/kg SC Q2W (n = 44). Step-up dosing was used to mitigate against severe cytokine release syndrome (CRS); required premedications were limited to step-up doses and the first full dose of talquetamab. Adverse events (AEs) were graded by CTCAE v4.03 with CRS events graded per Lee et al 2014 criteria. Investigators assessed responses per International Myeloma Working Group criteria. Results: As of Jan 17, 2022, pts in the 405 μg/kg/800 μg/kg groups, respectively, received a median of 6 /5 prior lines of therapy, 100%/98% were triple-class (TC) exposed, 77%/75% were TC refractory. Median follow-up (range) was 11.7 (1.0–21.2)/4.2 (0.7–13.7) months. Most AEs were grade 1 or 2. The most common AEs were cytopenias and CRS. Cytopenias (including neutropenia [67%/36%; grade 3/4: 53%/23%]) were reversible, mostly confined to step-up and cycle 1–2 doses, and generally resolved within 1 week. Infections occurred in 47%/34% (grade 3/4: 7%/9%) of pts. CRS (77%/80%; grade 3: 3%/0%) mostly occurred during step-up dosing. Skin-related and nail disorder AEs occurred in 83%/75% of pts (most commonly skin exfoliation: 37%/39% [all grade 1 and 2]). Dysgeusia (63%/57%) was generally mild and managed with dose adjustments. The overall response rates in response-evaluable pts were 70% (21/30 pts)/64% (28/44 pts); very good partial response or better rate: 57%/52%; median time to first confirmed response (range): 0.9 (0.2–3.8)/1.2 (0.3–6.8) months. Median duration of response will be reported. No pts died due to drug-related AEs. The PK and PD profiles of both RP2Ds appear comparable. Conclusions: These data show that both RP2Ds of talquetamab have comparable safety, efficacy, and pharmacokinetic profiles and confirm talquetamab as a novel, first-in-class therapy with highly promising efficacy in a heavily pretreated RRMM pt population. Clinical trial information: NCT03399799.

Targeting BCL-2 with venetoclax and dexamethasone in patients with relapsed/refractory t(11;14) multiple myeloma

Venetoclax (Ven) is a selective small-molecule inhibitor of BCL-2 that exhibits antitumoral activity against MM cells with t(11;14) translocation. We evaluated the safety and efficacy of Ven and dexamethasone (VenDex) combination in patients with t(11;14) positive relapsed/refractory (R/R) multiple myeloma (MM). This open-label, multicenter study had two distinct phases (phase one [P1], phase two [P2]). Patients in both phases received VenDex (oral Ven 800 mg/day + oral Dex 40 mg [20 mg for patients ≥75 years] on days 1, 8, and 15, per 21-day cycle). The primary objective of the P1 VenDex cohort was to assess safety and pharmacokinetics. Phase two further evaluated efficacy with objective response rate (ORR) and very good partial response or better. Correlative studies explored baseline BCL2 (BCL-2) and BCL2L1 (BCL-X_L ) gene expression, cytogenetics, and recurrent somatic mutations in MM. Twenty and 31 patients in P1 and P2 with t(11;14) positive translocation received VenDex. P1/P2 patients had received a median of 3/5 lines of prior therapy, and 20%/87% were refractory to daratumumab. Predominant grade 3/4 hematological adverse events (AEs) with ≥10% occurrence included lymphopenia (20%/19%), neutropenia (15%/7%), thrombocytopenia (10%/10%), and anemia (5%/16%). At a median follow-up of 12.3/9.2 months, ORR was 60%/48%. The duration of response estimate at 12 months was 50%/61%, and the median time to progression was 12.4/10.8 months. In biomarker evaluable patients, response to VenDex was independent of concurrent del(17p) or gain(1q) and mutations in key oncogenic signaling pathways, including MAPK and NF-kB. VenDex demonstrated efficacy and manageable safety in heavily-pre-treated patients with t(11;14) R/R MM.

Venetoclax and Navitoclax in Combination with Chemotherapy in Patients with Relapsed or Refractory Acute Lymphoblastic Leukemia and Lymphoblastic Lymphoma

Combining venetoclax, a selective BCL2 inhibitor, with low-dose navitoclax, a BCL-X_L/BCL2 inhibitor, may allow targeting of both BCL2 and BCL-X_L without dose-limiting thrombocytopenia associated with navitoclax monotherapy. The safety and preliminary efficacy of venetoclax with low-dose navitoclax and chemotherapy was assessed in this phase I dose-escalation study (NCT03181126) in pediatric and adult patients with relapsed/refractory (R/R) acute lymphoblastic leukemia or lymphoblastic lymphoma. Forty-seven patients received treatment. A recommended phase II dose of 50 mg navitoclax for adults and 25 mg for patients <45 kg with 400 mg adult-equivalent venetoclax was identified. Delayed hematopoietic recovery was the primary safety finding. The complete remission rate was 60%, including responses in patients who had previously received hematopoietic cell transplantation or immunotherapy. Thirteen patients (28%) proceeded to transplantation or CAR T-cell therapy on study. Venetoclax with navitoclax and chemotherapy was well tolerated and had promising efficacy in this heavily pretreated patient population. SIGNIFICANCE: In this phase I study, venetoclax with low-dose navitoclax and chemotherapy was well tolerated and had promising efficacy in patients with relapsed/refractory acute lymphoblastic leukemia or lymphoblastic lymphoma. Responses were observed in patients across histologic and genomic subtypes and in those who failed available therapies including stem cell transplant.See related commentary by Larkin and Byrd, p. 1324.This article is highlighted in the In This Issue feature, p. 1307.

IGF-1R/mTOR Targeted Therapy for Ewing Sarcoma: A Meta-Analysis of Five IGF-1R-Related Trials Matched to Proteomic and Radiologic Predictive Biomarkers

Background : Ten to fourteen percent of Ewing sarcoma (ES) study participants treated nationwide with IGF-1 receptor (IGF-1R)-targeted antibodies achieved tumor regression. Despite this success, low response rates and short response durations (approximately 7-weeks) have slowed the development of this therapy. Methods: We performed a meta-analysis of five phase-1b/2 ES-oriented trials that evaluated the anticancer activity of IGF-1R antibodies +/− mTOR inhibitors (mTORi). Our meta-analysis provided a head-to-head comparison of the clinical benefits of IGF-1R antibodies vs. the IGF-1R/mTOR-targeted combination. Available pretreatment clinical samples were semi-quantitatively scored using immunohistochemistry to detect proteins in the IGF-1R/PI3K/AKT/mTOR pathway linked to clinical response. Early PET/CT imaging, obtained within the first 2 weeks (median 10 days), were examined to determine if reduced FDG avidity was predictive of progression-free survival (PFS). Results: Among 56 ES patients treated at MD Anderson Cancer Center (MDACC) with IGF-1R antibodies, our analysis revealed a significant ~two-fold improvement in PFS that favored a combination of IGF-1R/mTORi therapy (1.6 vs. 3.3-months, p = 0.042). Low pIGF-1R in the pretreatment specimens was associated with treatment response. Reduced total-lesion glycolysis more accurately predicted the IGF-1R response than other previously reported radiological biomarkers. Conclusion: Synergistic drug combinations, and newly identified proteomic or radiological biomarkers of IGF-1R response, may be incorporated into future IGF-1R-related trials to improve the response rate in ES patients.

Type I insulin-like growth factor receptor signaling in hematological malignancies

The insulin-like growth factor (IGF) signaling system plays key roles in the establishment and progression of different types of cancer. In agreement with this idea, substantial evidence has shown that the type I IGF receptor (IGF-IR) and its primary ligand IGF-I are important for maintaining the survival of malignant cells of hematopoietic origin. In this review, we discuss current understanding of the role of IGF-IR signaling in cancer with a focus on the hematological neoplasms. We also address the emergence of IGF-IR as a potential therapeutic target for the treatment of different types of cancer including plasma cell myeloma, leukemia, and lymphoma.

Abstract CT100: First-in-human phase 1 trial of pyrimidine anti-metabolite FF-10502-01 in patients with advanced cancer

Background: FF10502-01 is a synthetic pyrimidine nucleoside analogue that is structurally similar to gemcitabine with a substitution of sulfur for oxygen in the pentose ring. FF-10502-01 showed potent anti-tumor activity in preclinical studies. In Capan-1 and SUIT-2 pancreatic ca xenograft models, FF-502-01 achieved superior tumor growth suppression and survival, respectively, compared to gemcitabine (gem), with less toxicity at clinically relevant doses. In gem-resistant pancreatic PDX models, FF-10502-01, alone and in combination with nab-paclitaxel (nab-pac), had higher efficacy and tolerability than gem/gem+nab-pac.

Methods: We conducted a standard 3+3, dose-escalation phase 1 trial with FF-10502-01 to determine safety, maximum tolerated dose (MTD), pharmacokinetics (PK), pharmacodynamics (PD) i.e. FF-10502 incorporation into peripheral blood cellular DNA, and preliminary antitumor activity. Eligibility criteria included age &gt;18 years, solid tumors refractory to standard treatment and adequate organ function. FF-10502-01 was administered IV over 60 minutes on days 1, 8, and 15 every 4 weeks. Planned dosing cohorts included 8, 12, 18, 27, 40, 60, 90, 135 and 200 mg/m2. Supportive medications such as anti-nausea prophylaxis were allowed.

Results: 22 patients (pts) have been treated in 6 dose cohorts of 8-60 mg/m2. The median number of cycles received was 2 (range 1 to &gt;12). Pts with the following cancers were enrolled: pancreatic (5 pts); ovarian and cholangiocarcinoma (3 each); parotid gland, prostate, and sarcoma (2 each); and endometrial, squamous cell carcinoma of the head and neck, anal, colon-neuroendocrine, and unknown primary (1 pt each). 11 pts were male and 11 female, median age 63 years (range 21-80), average number of prior cytotoxic therapies 3 (range 1-7) and 9 pts with prior gemcitabine therapy. Common related adverse events were Gr 1/2 nausea (43%), rash (38%), fever (29%), fatigue (19%), and vomiting despite prophylactic ondansetron and dexamethasone (14%). One pt had Gr 3 nausea (a DLT). Cytopenias have been minimal: 2 pts with Gr 1 and 2 anemia; with no neutropenia or thrombocytopenia. No pts have required dose reduction for toxicity. To date, an MTD has not been identified and enrollment continues. A pt with chondroblastic osteogenic sarcoma (18 mg/m2) achieved an unconfirmed partial response (73% decrease) in a maxillary mass but developed progressive disease at another site. 3 currently active patients (1 each of acinar pancreatic, prostate, parotid gland), demonstrated durable stable disease for &gt; 48, 40 and 28 weeks, respectively, at doses ranging from 8 to 27 mg/m2. FF-10502 plasma concentrations increased with dose. Additional PK and PD data will be presented.

Conclusions: The pyrimidine nucleoside antimetabolite FF-10502-01 is well tolerated with prophylactic anti-emetics and demonstrated preliminary antitumor activity in heavily pretreated patients.

Citation Format: Gerald Steven Falchook, Lindsay Bramwell, Lori Hannan, Deeksha Vishwamitra, Takayuki Yamada, Michele Rosner, David Wages, Thomas Myers, Linda Paradiso, Filip Janku. First-in-human phase 1 trial of pyrimidine anti-metabolite FF-10502-01 in patients with advanced cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT100. doi:10.1158/1538-7445.AM2017-CT100

IGF-1R and mTOR Blockade: Novel Resistance Mechanisms and Synergistic Drug Combinations for Ewing Sarcoma

BACKGROUND

Therapies cotargeting insulin-like growth factor receptor 1 (IGF-1R) and mammalian target of rapamycin (mTOR) have demonstrated remarkable, albeit short-lived, clinical responses in a subset of Ewing sarcoma (ES) patients. However, the mechanisms of resistance and applicable strategies for overcoming drug resistance to the IGF-1R/mTOR blockade are still undefined.

METHODS

To elucidate predominant mechanism(s) of acquired drug resistance while identifying synergistic drug combinations that improve clinical efficacy, we generated more than 18 ES cell lines resistant to IGF-1R- or mTOR-targeted therapy. Two small-molecule inhibitors of IGF-1R were chosen, NVP-ADW-742 (IGF-1R-selective) and OSI-906 (a dual IGF-1R/insulin receptor alpha [IR-α] inhibitor). Reverse-phase protein lysate arrays (RPPAs) revealed proteomic changes linked to IGF-1R/mTOR resistance, and selected proteins were validated in cell-based assays, xenografts, and within human clinical samples. All statistical tests were two-sided.

RESULTS

Novel mechanisms of resistance (MOR) emerged after dalotuzumab-, NVP-ADW-742-, and OSI-906-based targeting of IGF-1R. MOR to dalotuzumab included upregulation of IRS1, PI3K, and STAT3, as well as p38 MAPK, which was also induced by OSI-906. pEIF4E(Ser209), a key regulator of Cap-dependent translation, was induced in ridaforolimus-resistant ES cell lines. Unique drug combinations targeting IGF-1R and PI3K-alpha or Mnk and mTOR were synergistic in vivo and vitro (P < .001) as assessed respectively by Mantel-Cox and isobologram testing.

CONCLUSIONS

We discovered new druggable targets expressed by chemoresistant ES cells, xenografts, and relapsed human tumors. Joint suppression of these newfound targets, in concert with IGF-1R or mTOR blockade, should improve clinical outcomes.

SUMOylation Confers Posttranslational Stability on NPM-ALK Oncogenic Protein

Nucleophosmin-anaplastic lymphoma kinase–expressing (NPM-ALK⁺) T-cell lymphoma is an aggressive form of cancer that commonly affects children and adolescents. The expression of NPM-ALK chimeric oncogene results from the chromosomal translocation t(2;5)(p23;q35) that causes the fusion of the ALK and NPM genes. This translocation generates the NPM-ALK protein tyrosine kinase that forms the constitutively activated NPM-ALK/NPM-ALK homodimers. In addition, NPM-ALK is structurally associated with wild-type NPM to form NPM/NPM-ALK heterodimers, which can translocate to the nucleus. The mechanisms that sustain the stability of NPM-ALK are not fully understood. SUMOylation is a posttranslational modification that is characterized by the reversible conjugation of small ubiquitin-like modifiers (SUMOs) with target proteins. SUMO competes with ubiquitin for substrate binding and therefore, SUMOylation is believed to protect target proteins from proteasomal degradation. Moreover, SUMOylation contributes to the subcellular distribution of target proteins. Herein, we found that the SUMOylation pathway is deregulated in NPM-ALK⁺ T-cell lymphoma cell lines and primary lymphoma tumors from patients. We also identified Lys²⁴ and Lys³² within the NPM domain as the sites where NPM-ALK conjugates with SUMO-1 and SUMO-3. Importantly, antagonizing SUMOylation by the SENP1 protease decreased the accumulation of NPM-ALK and suppressed lymphoma cell viability, proliferation, and anchorage-independent colony formation. One possible mechanism for the SENP1-mediated decrease in NPM-ALK levels was the increase in NPM-ALK association with ubiquitin, which facilitates its degradation. Our findings propose a model in which aberrancies in SUMOylation contribute to the pathogenesis of NPM-ALK⁺ T-cell lymphoma. Unraveling such pathogenic mechanisms may lead to devising novel strategies to eliminate this aggressive neoplasm.

Abstract A36: Decreased levels of the transcription factors Ik-1 and MZF1 contribute to upregulation of IGF-IR expression in NPM-ALK+ T-cell anaplastic large-cell lymphoma

Type I insulin-like growth factor receptor (IGF-IR) tyrosine kinase is a homodimeric protein that is composed of 2 extracellular α; and 2 transmembranous β; subunits connected by disulfide bonds. IGF-IR belongs to the insulin receptor family whose members exhibit a common structural characteristic in the form of an amino acid motif (YXXXYY) within the activation loop of their respective kinase domains. Ligand stimulation of IGF-IR causes its dimerization, phosphorylation, and the subsequent activation of downstream signaling systems. It has been shown that IGF-IR is aberrantly overexpressed in and contributes to the survival of a variety of human solid tumors and hematological neoplasms and, therefore, it may represent an important therapeutic target. Pathological activation of IGF-IR induces cellular transformation and protection from apoptosis-- prerequisites for the establishment and growth of malignant tumors. Of important note is that the mechanisms underlying increased expression of IGF-IR in cancer cells are not completely understood. For instance, only a few transcription factors are known to bind the IGF-IR gene promoter (15q26.3) and modulate its activity through stimulation or inhibition. These transcription factors include Sp1, WT1, E2F1, STAT1, and EGR-1.

Recently, we identified IGF-IR as a major survival molecule that interacts reciprocally with nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) in a subtype of T-cell anaplastic large-cell lymphoma. NPM-ALK+ T-cell lymphoma is an aggressive type of cancer that is frequently encountered in children and young adults. Compared with its expression in normal human T lymphocytes and reactive lymphoid tissues, the expression of IGF-IR mRNA and protein is remarkably upregulated in NPM-ALK+ T-cell lymphoma cell lines and primary human tumors. Similar to other types of cancer, the mechanisms leading to increased expression of IGF-IR in NPM-ALK+ T-cell lymphoma have not been identified.

In this study, we hypothesized that increased IGF-IR expression can be explained by transcriptional aberrancies that exist inherently in NPM-ALK+ T-cell lymphoma. To identify transcription factors that may potentially bind to the human IGF-IR gene promoter, 3 web-based transcription factor search algorithms were used: TFSearch (www.cbrc.jp/research/db/TFSEARCH.html), Genomatix (www.genomatix.de), and MATCH (www.gene-regulation.com/pub/programs.html). These algorithms identified the transcription factors Ikaros (Ik) and myeloid zinc finger 1 (MZF1) to potentially bind to IGF-IR gene promoter. Western blotting (WB) studies demonstrated lower levels of Ik-1 and MZF1 in 5 NPM-ALK+ T-cell lymphoma cell lines than in T lymphocytes. WB also showed that Ik-1 and MZF1 are decreased in 85% and 100%, respectively, of 15 ALK+ T-cell lymphoma patient specimens. A luciferase assay supported that Ik-1 and MZF1 regulate the IGF-IR gene promoter. Furthermore, ChIP assay showed that these transcription factors bind specific sites located within the IGF-IR gene promoter. Forced expression of Ik-1 and MZF1 in NPM-ALK+ T-cell lymphoma cells significantly decreased IGF-IR mRNA and protein expression levels. This decrease in IGF-IR was associated with downregulation of pIGF-IR and the phosphorylation of its interacting molecules, including IRS-1, AKT, and NPM-ALK. In addition, overexpression of Ik-1 and MZF1 decreased the viability, proliferation, migration, and anchorage-independent colony formation of NPM-ALK+ T-cell lymphoma cells.

Collectively, our findings provide novel evidence that aberrant decreases in the transcription factors Ik-1 and MZF1 play important roles in the pathogenesis of NPM-ALK+ T-cell lymphoma through upregulation of IGF-IR expression. These findings could be exploited to devise more effective strategies to treat this lymphoma.

Citation Format: Deeksha Vishwamitra, Choladda V. Curry, Serhan Alkan, Ping Shi, Hesham M. Amin. Decreased levels of the transcription factors Ik-1 and MZF1 contribute to upregulation of IGF-IR expression in NPM-ALK+ T-cell anaplastic large-cell lymphoma. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A36.

The ALK inhibitor ASP3026 eradicates NPM-ALK⁺ T-cell anaplastic large-cell lymphoma in vitro and in a systemic xenograft lymphoma model

NPM-ALK⁺ T-cell anaplastic large-cell lymphoma (ALCL) is an aggressive type of cancer. Standard treatment of NPM-ALK⁺ ALCL is CHOP polychemotherapy. Although patients initially respond favorably to CHOP, resistance, relapse, and death frequently occur. Recently, selective targeting of ALK has emerged as an alternative therapeutic strategy. ASP3026 is a second-generation ALK inhibitor that can overcome crizotinib resistance in non-small cell lung cancer, and is currently being evaluated in clinical trials of patients with ALK⁺ solid tumors. However, NPM-ALK⁺ ALCL patients are not included in these trials. We studied the effects of ASP3026 on NPM-ALK⁺ ALCL cell lines in vitro and on systemic lymphoma growth in vivo. ASP3026 decreased the viability, proliferation, and colony formation, as well as induced apoptotic cell death of NPM-ALK⁺ ALCL cells. In addition, ASP3026 significantly reduced the proliferation of 293T cells transfected with NPM-ALK mutants that are resistant to crizotinib and downregulated tyrosine phosphorylation of these mutants. Moreover, ASP3026 abrogated systemic NPM-ALK⁺ ALCL growth in mice. Importantly, the survival of ASP3026-treated mice was superior to that of control and CHOP-treated mice. Our data suggest that ASP3026 is an effective treatment for NPM-ALK⁺ ALCL, and support the enrollment of patients with this lymphoma in the ongoing clinical trials.

The transcription factors Ik-1 and MZF1 downregulate IGF-IR expression in NPM-ALK⁺ T-cell lymphoma

Background

The type I insulin-like growth factor receptor (IGF-IR) tyrosine kinase promotes the survival of an aggressive subtype of T-cell lymphoma by interacting with nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) oncogenic protein. NPM-ALK⁺ T-cell lymphoma exhibits much higher levels of IGF-IR than normal human T lymphocytes. The mechanisms underlying increased expression of IGF-IR in this lymphoma are not known. We hypothesized that upregulation of IGF-IR could be attributed to previously unrecognized defects that inherently exist in the transcriptional machinery in NPM-ALK⁺ T-cell lymphoma.

Methods and results

Screening studies showed substantially lower levels of the transcription factors Ikaros isoform 1 (Ik-1) and myeloid zinc finger 1 (MZF1) in NPM-ALK⁺ T-cell lymphoma cell lines and primary tumor tissues from patients than in human T lymphocytes. A luciferase assay supported that Ik-1 and MZF1 suppress IGF-IR gene promoter. Furthermore, ChIP assay showed that these transcription factors bind specific sites located within the IGF-IR gene promoter. Forced expression of Ik-1 or MZF1 in the lymphoma cells decreased IGF-IR mRNA and protein. This decrease was associated with downregulation of pIGF-IR, and the phosphorylation of its interacting proteins IRS-1, AKT, and NPM-ALK. In addition, overexpression of Ik-1 and MZF1 decreased the viability, proliferation, migration, and anchorage-independent colony formation of the lymphoma cells.

Conclusions

Our results provide novel evidence that the aberrant decreases in Ik-1 and MZF1 contribute significantly to the pathogenesis of NPM-ALK⁺ T-cell lymphoma through the upregulation of IGF-IR expression. These findings could be exploited to devise new strategies to eradicate this lymphoma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0324-2) contains supplementary material, which is available to authorized users.

Abstract A80: In vitro and in vivo antitumor activity of the selective ALK inhibitor ASP3026 against NPM-ALK+ T-cell anaplastic large-cell lymphoma

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase with structural similarities to the insulin receptor. ALK is physiologically expressed in neuronal cells at early stages of human development. Thereafter, ALK expression is largely limited to malignant neoplasms including T-cell anaplastic large-cell lymphoma (ALCL), non-small cell lung cancer (NSCLC), and neuroblastoma. It has been previously established that ALK, in the form of chimeric proteins or constitutively activated mutants, plays a central role in the survival of these tumors. Hence, targeting ALK is considered a legitimate and likely successful strategy to eradicate these tumors. Nucleophosmin-ALK-expressing (NPM-ALK+) T-cell ALCL is an aggressive type of cancer. It is one of the most common hematological neoplasms in children as it comprises 40% of the non-Hodgkin lymphomas in this age group. Recently, a selective ALK inhibitor, ASP3026, was developed utilizing an ALK kinase inhibition assay aimed at the chimeric tyrosine kinase echinoderm-microtubule-associated protein-like 4-ALK (EML4-ALK), which is expressed in a subgroup of NSCLC tumors.1 Initial studies showed that not only ASP3026 possesses remarkable inhibitory effects on EML4-ALK but also it overcomes the resistance of EML4-ALK+ NSCLC to crizotinib; a prototype ALK and c-MET inhibitor. ASP3026 is currently being tested in phase I clinical trials that include EML4-ALK+ NSCLC patients. Of important note is that the effects and therapeutic potential of ASP3026 in NPM-ALK+ T-cell ALCL are not known. We systematically analyzed the effects of ASP3026 (ChemieTek, Indianapolis, IN) in NPM-ALK+ T-cell ALCL using in vitro and in vivo experimental approaches. ASP3026 (0.1 to 3.0 µM; 24 and 72 h) induced a concentration- and time-dependent decrease in the viability and proliferation of NPM-ALK+ T-cell ALCL cell lines including Karpas 299, SU-DHL-1, SUP-M2, SR-786, and DEL. In contrast, these negative effects were not observed in normal human T lymphocytes. Furthermore, ASP3026 reduced anchorage-independent colony formation of NPM-ALK+ T-cell ALCL cells. The effects of ASP3026 could be explained, at least in part, by successful induction of apoptotic cell death in these cells. At the biochemical level, ASP3026 decreased significantly the levels of pNPM-ALK and the activated/phosphorylated form of its interacting oncogenic protein type I insulin-like growth factor receptor (pIGF-IR). We are performing additional experiments to further characterize the biochemical effects of ASP3026 in NPM-ALK+ T-cell ALCL cells. To further evaluate the therapeutic potential of ASP3026, we utilized an in vivo systemic lymphoma model developed in our laboratory. Briefly, Karpas 299 cells (1 × 106 cells per mouse), engineered to simultaneously express humanized firefly luciferase and GFP, were injected intravenously in CB-17 SCID mice (Taconic; female; 6-8 weeks old). Systemic lymphoma tumors, detected by using IVIS whole body imaging system after intraperitoneal injection of D-lucifern, were established at approximately 3 weeks after lymphoma cell injections.Thereafter, vehicle or ASP3026 (30 mg/kg/day) was administered daily to the mice (10 mice per group) through oral gavage. Also, standard CHOP combination chemotherapy was used in another group. Treatment with ASP3026 for only 2 weeks was associated with complete lymphoma eradication, which persisted with the daily administration of ASP3026 and until study termination at 6-8 weeks from treatment initiation. In contrast, cessation of ASP3026 after 2 weeks of treatment was associated with lymphoma relapse. Although CHOP initially eradicated the lymphoma, most of the CHOP-treated mice developed significant toxicity and relapsed at 4 weeks after treatment. Importantly, vehicle- and CHOP-treated mice had inferior overall survival compared with mice treated with ASP3026. Taken together, our results provide strong evidence that ASP3026 could represent a novel approach to efficiently treat NPM-ALK+ T-cell ALCL.

1Kuromitsu S, et al. Mol. Cancer Ther. 2011;10[Supp. 1]: A227

DV and SKG equally contributed to this work

Citation Format: Deeksha Vishwamitra, Suraj Konnath George, Roxsan Manshouri, Ping Shi, Hesham M. Amin. In vitro and in vivo antitumor activity of the selective ALK inhibitor ASP3026 against NPM-ALK+ T-cell anaplastic large-cell lymphoma. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A80.

NPM-ALK up-regulates iNOS expression through a STAT3/microRNA-26a-dependent mechanism

NPM-ALK chimeric oncogene is aberrantly expressed in an aggressive subset of T-cell lymphomas that frequently occurs in children and young adults. The mechanisms underlying the oncogenic effects of NPM-ALK are not completely elucidated. Inducible nitric oxide synthase (iNOS) promotes the survival and maintains the malignant phenotype of cancer cells by generating NO, a highly active free radical. We tested the hypothesis that iNOS is deregulated in NPM-ALK(+) T-cell lymphoma and promotes the survival of this lymphoma. In line with this possibility, an iNOS inhibitor and NO scavenger decreased the viability, adhesion, and migration of NPM-ALK(+) T-cell lymphoma cells, and an NO donor reversed these effects. Moreover, the NO donor salvaged the viability of lymphoma cells treated with ALK inhibitors. In further support of an important role of iNOS, we found iNOS protein to be highly expressed in NPM-ALK(+) T-cell lymphoma cell lines and in 79% of primary tumours but not in human T lymphocytes. Although expression of iNOS mRNA was identified in NPM-ALK(+) T-cell lymphoma cell lines and tumours, iNOS mRNA was remarkably elevated in T lymphocytes, suggesting post-transcriptional regulation. Consistently, we found that miR-26a contains potential binding sites and interacts with the 3'-UTR of iNOS. In addition, miR-26a was significantly decreased in NPM-ALK(+) T-cell lymphoma cell lines and tumours compared with T lymphocytes and reactive lymph nodes. Restoration of miR-26a in lymphoma cells abrogated iNOS protein expression and decreased NO production and cell viability, adhesion, and migration. Importantly, the effects of miR-26a were substantially attenuated when the NO donor was simultaneously used to treat lymphoma cells. Our investigation of the mechanisms underlying the decrease in miR-26a in this lymphoma revealed novel evidence that STAT3, a major downstream substrate of NPM-ALK tyrosine kinase activity, suppresses MIR26A1 gene expression.

MicroRNA 96 is a post-transcriptional suppressor of anaplastic lymphoma kinase expression

Anaplastic lymphoma kinase (ALK) constitutes a part of the oncogenic fusion proteins nucleophosmin-ALK and echinoderm microtubule-associated protein like 4-ALK, which are aberrantly expressed in a subset of T-cell anaplastic large-cell lymphoma and non-small-cell lung cancer, respectively. The expression of mutated, constitutively active ALK also occurs in a subset of neuroblastoma tumors. ALK is believed to play an important role in promoting tumor survival. Nevertheless, the mechanisms underlying the expression of ALK in cancer cells are not completely known. MicroRNA (miR) has been implicated in the regulation of the expression of both oncogenes and tumor suppressor genes. We tested the hypothesis that the expression of ALK could be regulated by miR. Three Internet-based algorithms identified miR-96 to potentially bind with the ALK 3'-untranslated region. Notably, miR-96 levels were markedly decreased in ALK-expressing cancer cell lines and primary human tumors compared with their normal cellular and tissue counterparts. Transfection of the cell lines with miR-96 decreased levels of the different forms of ALK protein, without significant effects on ALK mRNA. Furthermore, miR-96 decreased the phosphorylation of ALK target proteins, including Akt, STAT3, JNK, and type I insulin-like growth factor receptor, and it down-regulated JunB. These effects were associated with reduced proliferation, colony formation, and migration of ALK-expressing cancer cells. These data provide novel evidence that decreases in miR-96 could represent a mechanism underlying the aberrant expression of ALK in cancer cells.

Expression and effects of inhibition of type I insulin-like growth factor receptor tyrosine kinase in mantle cell lymphoma

BACKGROUND

Type I insulin-like growth factor receptor (IGF-IR) tyrosine kinase induces significant oncogenic effects. Strategies to block IGF-IR signaling are being tested in clinical trials that include patients with aggressive solid malignancies. Mantle cell lymphoma is a B-cell neoplasm with poor prognosis and a tendency to develop resistance. The expression and potential significance of IGF-IR in mantle cell lymphoma are not known.

DESIGN AND METHODS

We used reverse transcriptase polymerase chain reaction, quantitative real-time polymerase chain reaction, immunoprecipitation, western blotting, flow cytometry, and immunohistochemistry to analyze the expression of IGF-IR mRNA, and IGF-IR and pIGF-IR proteins in mantle cell lymphoma cell lines and patients' specimens. Selective and specific blockade of IGF-IR was achieved using picropodophyllin and short-interfering RNA, respectively. Cell viability, apoptosis, cell cycle, cellular morphology, cell proliferation, and target proteins were then analyzed.

RESULTS

We detected the expression of IGF-IR and pIGF-IR in mantle cell lymphoma cell lines. Notably, IGF-IR molecules/cell were markedly increased in mantle cell lymphoma cell lines compared with human B-lymphocytes. IGF-IR and pIGF-IR were also detected in 78% and 74%, respectively, of 23 primary mantle cell lymphoma specimens. Treatment of serum-deprived mantle cell lymphoma cell lines with IGF-I salvaged these cells from apoptosis. Selective inhibition of IGF-IR by picropodophyllin decreased the viability and proliferation of mantle cell lymphoma cell lines, and induced apoptosis and cell cycle arrest. Selective inhibition of IGF-IR was associated with caspase-3, caspase-8, caspase-9, and PARP cleavage, cytochrome c release, up-regulation of cyclin B1, and down-regulation of cyclin D1, pCdc2, pIRS-1, pAkt, and pJnk. Similar results were obtained by using IGF-IR short-interfering RNA. In addition, picropodophyllin decreased the viability and proliferation of primary mantle cell lymphoma cells that expressed IGF-IR.

CONCLUSIONS

IGF-IR is up-regulated and frequently activated in mantle cell lymphoma. Our data suggest that IGF-IR could be a molecular target for the treatment of mantle cell lymphoma.