Identification of compounds that preferentially suppress the growth of T‐cell acute lymphoblastic leukemia‐derived cells

DuVall A.S., Sheade J., Anderson D., Yates S.J., Stock W.

The treatment of acute lymphoblastic leukemia (ALL) has dramatically changed over the past three decades. However, relapsed and/or refractory ALL still remains with a very low survival and high morbidity associated with its treatment. Here, we will review the outstanding progress that has been made in the treatment of relapsed and/or refractory ALL and discuss future directions and challenges that require further investigation.

Yoshida C., Higashi T., Hachiro Y., Fujita Y., Yagi T., Takechi A., Nakata C., Miyashita K., Kitada N., Saito R., Obata R., Hirano T., Hara T., Maki S.A.

T-cell acute lymphoblastic leukemia (T-ALL) is a hardly curable disease with a high relapse rate. 20 analogs were synthesized based on the structures of two kinds of fungi-derived polyenylpyrrole products (rumbrin (1) and auxarconjugatin-B (2)) to suppress the growth of T-ALL-derived cell line CCRF-CEM and tested for growth-inhibiting activity. The octatetraenylpyrrole analog gave an IC50 of 0.27 μM in CCRF-CEM cells, while it did not affect Burkitt lymphoma-derived cell line Raji and the cervical cancer cell line HeLa, or the oral cancer cell line HSC-3 (IC50 > 10 μM). This compound will be a promising compound for developing T-ALL-specific drugs.

Pullarkat V.A., Lacayo N.J., Jabbour E., Rubnitz J.E., Bajel A., Laetsch T.W., Leonard J., Colace S.I., Khaw S.L., Fleming S.A., Mattison R.J., Norris R., Opferman J.T., Roberts K.G., Zhao Y., et. al.

Abstract Combining venetoclax, a selective BCL2 inhibitor, with low-dose navitoclax, a BCL-XL/BCL2 inhibitor, may allow targeting of both BCL2 and BCL-XL 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

Cordo' V., van der Zwet J.C., Canté-Barrett K., Pieters R., Meijerink J.P.

Abstract T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy characterized by aberrant proliferation of immature thymocytes. Despite an overall survival of 80% in the pediatric setting, 20% of patients with T-ALL ultimately die from relapsed or refractory disease. Therefore, there is an urgent need for novel therapies. Molecular genetic analyses and sequencing studies have led to the identification of recurrent T-ALL genetic drivers. This review summarizes the main genetic drivers and targetable lesions of T-ALL and gives a comprehensive overview of the novel treatments for patients with T-ALL that are currently under clinical investigation or that are emerging from preclinical research. Significance: T-ALL is driven by oncogenic transcription factors that act along with secondary acquired mutations. These lesions, together with active signaling pathways, may be targeted by therapeutic agents. Bridging research and clinical practice can accelerate the testing of novel treatments in clinical trials, offering an opportunity for patients with poor outcome.

Fattizzo B., Rosa J., Giannotta J.A., Baldini L., Fracchiolla N.S.

T-cell acute lymphoblastic leukemia/ lymphoma is an aggressive haematological neoplasm whose classification is still based on immunephenotypic findings. Frontline treatment encompass high intensity combination chemotherapy with good overall survival; however, relapsing/refractory patients have very limited options. In the last years, the understanding of molecular physiopathology of this disease, lead to the identification of a subset of patients with peculiar genetic profile, namely “early T-cell precursors” lymphoblastic leukemia, characterized by dismal outcome and indication to frontline allogeneic bone marrow transplant. In general, the most common mutations occur in the NOTCH1/FBXW7 pathway (60% of adult patients), with a positive prognostic impact. Other pathogenic steps encompass transcriptional deregulation of oncogenes/oncosuppressors, cell cycle deregulation, kinase signaling (including IL7R-JAK-STAT pathway, PI3K/AKT/mTOR pathway, RAS/MAPK signaling pathway, ABL1 signaling pathway), epigenetic deregulation, ribosomal disfunction, and altered expression of oncogenic miRNAs or long non coding RNA. The insight in the genomic landscape of the disease paves the way to the use of novel targeted drugs that might improve the outcome, particularly in relapse/refractory patients. In this review, we analyse available literature on T-ALL pathogenesis, focusing on molecular aspects of clinical, prognostic, and therapeutic significance.

Miyashita K., Kitajima K., Goyama S., Kitamura T., Hara T.

T cell acute lymphoblastic leukemia (T-ALL) is a malignant cancer with poor prognosis. The transcriptional co-factor LIM domain only 2 (LMO2) and its target gene HHEX are essential for self-renewal of T cell precursors and T-ALL etiology. LMO2 directly associates with LDB1 in a large DNA-containing nuclear complex and controls the transcription of T-ALL-related genes. Recently, we reported that overexpression of the LIM-homeodomain transcription factor, Lhx2, results in liberation of the Lmo2 protein from the Lmo2-Ldb1 complex, followed by ubiquitin proteasome mediated degradation. Here, we found that proliferation of five human T-ALL-derived cell lines, including CCRF-CEM, was significantly suppressed by retroviral overexpression of Lhx2. The majority of Lhx2-transduced CCRF-CEM cells arrested in G0 phase and subsequently underwent apoptosis. Expression of LMO2 protein as well as HHEX, ERG, HES1 and MYC genes was repressed in CCRF-CEM cells by transduction with Lhx2. Lhx2-mediated growth inhibition was partially rescued by simultaneous overexpression of Lmo2; however, both the C-terminal LIM domain and the homeodomain of Lhx2 were required for its growth-suppressive activity. These data indicate that Lhx2 is capable of blocking proliferation of T-ALL-derived cells by both LMO2-dependent and -independent means. We propose Lhx2 as a new molecular tool for anti-T-ALL drug development.

Girardi T., Vicente C., Cools J., De Keersmaecker K.

Abstract T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy caused by the accumulation of genomic lesions that affect the development of T cells. For many years, it has been established that deregulated expression of transcription factors, impairment of the CDKN2A/2B cell-cycle regulators, and hyperactive NOTCH1 signaling play prominent roles in the pathogenesis of this leukemia. In the past decade, systematic screening of T-ALL genomes by high-resolution copy-number arrays and next-generation sequencing technologies has revealed that T-cell progenitors accumulate additional mutations affecting JAK/STAT signaling, protein translation, and epigenetic control, providing novel attractive targets for therapy. In this review, we provide an update on our knowledge of T-ALL pathogenesis, the opportunities for the introduction of targeted therapy, and the challenges that are still ahead.

Hua K., Liao P., Fang Z., Yang F., Yang Y., Chen Y., Chiu Y., Liu M., Lam Y., Wu S.

Oral squamous cell carcinoma (OSCC) accounts for 5.8% of all malignancies in Taiwan and the incidence of OSCC is on the rise. OSCC is also a common malignancy worldwide and the five-year survival rate remains poor. Therefore, new and effective treatments are needed to control OSCC. In the present study we have investigated the efficacy and associated mechanisms of polyenylpyrroles and their analogs in both in vitro cell culture and in vivo nude mice xenografts. Auxarconjugatin B (compound 1a) resulted in cell cycle arrest in the G2/M phase and caspase-dependent apoptosis in OEC-M1 and HSC-3 cells by activating DNA damage and mitochondria dysfunction through the loss of mitochondrial membrane potential, release of cytochrome c, increase in B-cell lymphoma-2-associated X protein level, and decrease in B-cell lymphoma-2 level. Compound 1a-induced generation of intracellular reactive oxygen species through cytochrome P450 1A1 was identified as a major mechanism of its effect for DNA damage, mitochondria dysfunction and apoptosis, which was reversed by antioxidant N-acetylcysteine as well as cytochrome P450 1A1 inhibitor and specific siRNA. Furthermore, compound 1a-treated nude mice showed a reduction in the OEC-M1 xenograft tumor growth and an increase in the caspase-3 activation in xenograft tissue. These results provide promising insights as to how compound 1a mediates cytotoxicity and may prove to be a molecular rationale for its translation into a potential therapeutic against OSCC.

Hunger S.P., Lu X., Devidas M., Camitta B.M., Gaynon P.S., Winick N.J., Reaman G.H., Carroll W.L.

Purpose To examine population-based improvements in survival and the impact of clinical covariates on outcome among children and adolescents with acute lymphoblastic leukemia (ALL) enrolled onto Children's Oncology Group (COG) clinical trials between 1990 and 2005. Patients and Methods In total, 21,626 persons age 0 to 22 years were enrolled onto COG ALL clinical trials from 1990 to 2005, representing 55.8% of ALL cases estimated to occur among US persons younger than age 20 years during this period. This period was divided into three eras (1990-1994, 1995-1999, and 2000-2005) that included similar patient numbers to examine changes in 5- and 10-year survival over time and the relationship of those changes in survival to clinical covariates, with additional analyses of cause of death. Results Five-year survival rates increased from 83.7% in 1990-1994 to 90.4% in 2000-2005 (P < .001). Survival improved significantly in all subgroups (except for infants age ≤ 1 year), including males and females; those age 1 to 9 years, 10+ years, or 15+ years; in whites, blacks, and other races; in Hispanics, non-Hispanics, and patients of unknown ethnicity; in those with B-cell or T-cell immunophenotype; and in those with National Cancer Institute (NCI) standard- or high-risk clinical features. Survival rates for infants changed little, but death following relapse/disease progression decreased and death related to toxicity increased. Conclusion This study documents ongoing survival improvements for children and adolescents with ALL. Thirty-six percent of deaths occurred among children with NCI standard-risk features emphasizing that efforts to further improve survival must be directed at both high-risk subsets and at those children predicted to have an excellent chance for cure.

Fang Z., Liao P., Yang Y., Yang F., Chen Y., Lam Y., Hua K., Wu S.

A class of polyenylpyrroles and their analogues were designed from a hit compound identified in a fungus. The compounds synthesized were evaluated for their cell cytotoxicity against human non-small-cell lung carcinoma cell lines A549. Two compounds were found to exhibit high cytotoxicity against A549 cells with IC(50) of 0.6 and 0.01 μM, respectively. The underlying mechanisms for the anticancer activity were demonstrated as caspases activation dependent apoptosis induction through loss of mitochondrial membrane potential, release of cytochrome c, increase in B-cell lymphoma-2-associated X protein (Bax) level, and decrease in B-cell lymphoma-2 (Bcl-2) level. The two compounds were nontoxic to normal human lung Beas-2b cells (IC(50) > 80 μM), indicating that they are highly selective in their cytotoxicity activities. Furthermore, one compound showed in vivo anticancer activity in human-lung-cancer-cell-bearing mice. These results open promising insights on how these conjugated polyenes mediate cytotoxicity and may provide a molecular rationale for future therapeutic interventions in carcinogenesis.

Pui C., Robison L.L., Look A.T.

Acute lymphoblastic leukaemia, a malignant disorder of lymphoid progenitor cells, affects both children and adults, with peak prevalence between the ages of 2 and 5 years. Steady progress in development of effective treatments has led to a cure rate of more than 80% in children, creating opportunities for innovative approaches that would preserve past gains in leukaemia-free survival while reducing the toxic side-effects of current intensive regimens. Advances in our understanding of the pathobiology of acute lymphoblastic leukaemia, fuelled by emerging molecular technologies, suggest that drugs specifically targeting the genetic defects of leukaemic cells could revolutionise management of this disease. Meanwhile, studies are underway to ascertain the precise events that take place in the genesis of acute lymphoblastic leukaemia, to enhance the clinical application of known risk factors and antileukaemic agents, and to identify treatment regimens that might boost the generally low cure rates in adults and subgroups of children with high-risk leukaemia.

DeAngelo D.J., Yu D., Johnson J.L., Coutre S.E., Stone R.M., Stopeck A.T., Gockerman J.P., Mitchell B.S., Appelbaum F.R., Larson R.A.

AbstractNelarabine (506U78) is a soluble pro-drug of 9-β-d-arabinofuranosylguanine (ara-G), a deoxyguanosine derivative. We treated 26 patients with T-cell acute lymphoblastic leukemia (T-ALL) and 13 with T-cell lymphoblastic lymphoma (T-LBL) with nelarabine. All patients were refractory to at least one multiagent regimen or had relapsed after achieving a complete remission. Nelarabine was administered on an alternate day schedule (days 1, 3, and 5) at 1.5 g/m2/day. Cycles were repeated every 22 days. The median age was 34 years (range, 16-66 years); 32 (82%) patients were male. The rate of complete remission was 31% (95% confidence interval [CI], 17%, 48%) and the overall response rate was 41% (95% CI, 26%, 58%). The principal toxicity was grade 3 or 4 neutropenia and thrombocytopenia, occurring in 37% and 26% of patients, respectively. There was only one grade 4 adverse event of the nervous system, which was a reversible depressed level of consciousness. The median disease-free survival (DFS) was 20 weeks (95% CI, 11, 56), and the median overall survival was 20 weeks (95% CI, 13, 36). The 1-year overall survival was 28% (95% CI, 15%, 43%). Nelarabine is well tolerated and has significant antitumor activity in relapsed or refractory T-ALL and T-LBL.

Pui C., Evans W.E.

Although the overall cure rate of acute lymphoblastic leukemia (ALL) in children is about 80 percent, affected adults fare less well. This review considers recent advances in the treatment of ALL, emphasizing issues that need to be addressed if treatment outcome is to improve further.

Svingen T., Tonissen K.F.

Human HOX genes are expressed in a spatio-temporal fashion during embryogenesis and early development where they act as master transcriptional regulators. HOX genes are also expressed in normal adult cells, potentially in a tissue specific manner involving maintenance of the normal phenotype. In selected oncogenic transformations, mis-expression of many HOX genes have been shown, indicating an involvement of these transcriptional regulators in carcinogenesis and metastasis. Utilising quantitative real-time RT-PCR assays, the expression of 20 HOX genes and two known HOX co-factors, PBX1B and MEIS1, were analysed in human melanoma and breast cancer cell lines, comparing results against non-malignant cells. Alterations in HOX gene expression were observed for all malignant cells examined, with some dysregulated transcript levels seemingly random, and the expression of other HOX genes apparently following the same patterns in both skin and breast cancer establishment. Furthermore, HOX gene expression was correlated with the invasive capacity of the cells. The expression of the HOX co-factors PBX1B and MEIS1 showed no marked changes from the non-malignant to the malignant phenotypes, further indicating that it is dysregulated HOX gene expression, rather than dysregulated gene expression of HOX co-factors, that potentially commit the cell to re-differentiate and undergo oncogenic transformation.

Hosoe T., Fukushima K., Takizawa K., Miyaji M., Kawai K.

The red pigments, auxarconjugatins A, B and C, were isolated from mycelia of Auxarthron conjugatum, an ascomycetous fungus belonging to the Onygenaceae, in which the causative fungi of severe mycoses also belong. The structures of auxarconjugatins A, B and C, including the stereochemistry of the conjugated tetraene, were established by spectroscopic analyses. These compounds were in equilibrium with a few double bond stereoisomers of the double bonds when dissolved in MeOH or MeCN.

Higashi T., Yoshida C., Hachiro Y., Nakata C., Takechi A., Yagi T., Miyashita K., Kitada N., Obata R., Hirano T., Hara T., Maki S.A.

To develop novel drugs for treating T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML) which are highly malignant hematological tumors, a series of analogs having a polyenylpyrrole structure of natural compounds (rumbrin and auxarconjugatin B) were synthesized and investigated their structure-activity relationships (SAR) of in vitro anti-T-ALL and anti-AML activities. We obtained three findings: (1) introduction of a methyl group at the conjugated polyene terminus enhanced anti-T-ALL activity, (2) analogs with a 3-chloropyrrole moiety had even higher selectivity for T-ALL cells, and (3) some analogs were effective against AML-derived cells. Among the studied compounds, 3-chloro-2-(8-ethoxycarbonylnona-1,3,5,7-tetraenyl) pyrrole 4e was the most promising candidate of T-ALL- and AML-treating drug. This study provides useful structural information for designing novel drugs treating T-ALL and AML.