Monogenic deficiency in murine intestinal Cdc42 leads to mucosal inflammation that induces crypt dysplasia

CDC42 controls intestinal epithelial (IEC) stem cell (IESC) division. How aberrant CDC42 initiates intestinal inflammation or neoplasia is unclear. We utilized models of inflammatory bowel diseases (IBD), colorectal cancer, aging, and IESC injury to determine the loss of intestinal Cdc42 upon inflammation and neoplasia. Intestinal specimens were collected to determine the levels of CDC42 in IBD or colorectal cancer. Cdc42 floxed mice were crossed with Villin-Cre, Villin-CreERT2 and/or Lgr5-eGFP-IRES-CreERT2, or Bmi1-CreERT2 mice to generate Cdc42 deficient mice. Irradiation, colitis, aging, and intestinal organoid were used to evaluate CDC42 upon mucosal inflammation, IESC/progenitor regenerative capacity, and IEC repair. Our studies revealed that increased CDC42 in colorectal cancer correlated with lower survival; in contrast, lower levels of CDC42 were found in the inflamed IBD colon. Colonic Cdc42 depletion significantly reduced Lgr5+ IESCs, increased progenitors' hyperplasia, and induced mucosal inflammation, which led to crypt dysplasia. Colonic Cdc42 depletion markedly enhanced irradiation- or chemical-induced colitis. Depletion or inhibition of Cdc42 reduced colonic Lgr5+ IESC regeneration. In conclusion, depletion of Cdc42 reduces the IESC regeneration and IEC repair, leading to prolonged mucosal inflammation. Constitutive monogenic loss of Cdc42 induces mucosal inflammation, which could result in intestinal neoplasia in the context of aging.

Real-world evidence of incidence and outcomes of aplastic anaemia following administration of immune checkpoint inhibitors

Aplastic anaemia (AA) is a rare immune-related adverse events (irAEs) after immune checkpoint inhibitors (ICIs) administration with poorly understood incidence and outcomes. We analysed an electronic health record database of 52 303 ICI-treated patients and found 77 (0.15%) cases of AA, with a median onset of 126 days (interquartile range, 58-363 days). The most used treatment for AA was systemic glucocorticoids 60 (77.9%) and 32 (41.6%) patients were able to resume ICI within 1 year. Patients diagnosed with AA had a steep decline in overall survival (OS) within the first 120 days; when compared to propensity score-matched patients without AA, they had a significantly worse OS (hazard ratio 1.72, 95% confidence interval 1.19-2.50; p = 0.003).

Abstract 1233: Depletion of Apc gene in Cdx2 gastro-intestinal cells facilitates metastasis of colorectal adenocarcinoma Lgr5 cells to distant organs

Background: CDX2 is a transcription factor expressed in the gastro-intestinal (GI) epithelial (IEC) and stromal cells. CDX2 along with APC can regulate Lgr5 intestinal stem cell (ISC) differentiation to control GI development or neoplasia. CDX2 or APC loss function is associated with CRC advance. However, whether APC directly regulates CRC metastasis is not clear. We aim to determine the role of inactive Apc gene in Cdx2 GI cells on Lgr5 ISC metastasis.

Methods: Tissue sections were collected from CRC or CRC hepatic-metastatic patients, CDX2, CTNNB1, α-SMA, APC and LGR5 expressions were examined. Apc flox mice were crossed with Lgr5CreER and/or Cdx2CreER mice to inactivate Apc gene in Lgr5 ISCs, Cdx2 IECs or stromal cells. Cdx2CreER;Apc mice were then crossed with tgfr2 flox mice to deplete tgfr2 in the Apc-deficient Cdx2 cells. GI tract and liver histology was evaluated and the expression of Lgr5, APC, α-SMA, β-catenin, and CDX2 were examined. The colorectal polyps induced by Apc inactivation were dissected, total RNA was extracted to perform RNA-Seq and quantitative PCR analyses. The colorectal organoids were differentiated and transplanted into abdominal cavity of recipient mice. Meanwhile, HT-29 cells were transfected with APC and/or CDX2 gRNAs.

Results: CTNNB1 and LGR5 expression were increased in human CRC and hepatic-metastatic CRC while interstitial CDX2 and SMA colocalization were robustly pronounced compared to normal colorectum. TCGA analysis showed the positive correlation of APC lower and CDX2 higher with metastatic rectal cancer. Apc depletion in Lgr5 cells in 6-week-old mice led to Lgr5+ rectal adenocarcinoma and Lgr5 crypts in liver while depletion of Apc in Lgr5 cells in 3-month-old mice only resulted in Lgr5 intestinal adenoma. Apc depletion in Cdx2 cells led to rectal fibroma and intestinal adenoma as well as undifferentiated metastatic Lgr5 cells in liver. Notably, Apc depletion decreased crypt CDX2 while increased colocalization of CDX2 and α-SMA in the stromal cells of adenocarcinoma, and increased expression of TGFBβr2, β-catenin, and epithelial-mesenchymal transition (EMT) markers (Fibronectin and Vimentin). Finally, tgfr2 depletion in Apc-inactive Cdx2 cells impaired GI cancer cell metastasis to liver. Colorectal orgnoids exhibited cancer phenotypes upon Apc depletion in CDX2 or Lgr5 cells. Intra-abdominal xenotransplantation exhibited that organoids with Apc deficiency in Lgr5 cells appeared no colonization on or invasion of liver tissues whereas the organoids with Apc deficiency in Cdx2 cells invaded liver.

Conclusion: Reduced Apc in Cdx2 cells are required for Lgr5 cell transformation to Lgr5- cancer stem cells. Inactive intestinal Apc increases Cdx2-α-SMA stromal niche cells and facilitates Lgr5 ISC metastasis to liver partially through TGF-β and/or wnt-dependent EMT mechanisms.

Citation Format: Ahmed Bakheet, Wen Gao, Dan Cai, Nathan Berger, William Tse, Xiaonan Han. Depletion of Apc gene in Cdx2 gastro-intestinal cells facilitates metastasis of colorectal adenocarcinoma Lgr5 cells to distant organs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1233.

Early versus late response to daratumumab-based triplet therapies in patients with multiple myeloma: a pooled analysis of trials POLLUX, CASTOR and MAIA

In multiple myeloma (MM), it is unclear whether early and late responders to daratumumab have similar outcomes. We pooled individual-level data from phase 3 trials and divided them into early and late response groups based on median time to response. Altogether 670 and 213 patients achieved very good partial response (VGPR) or better and minimal residual disease (MRD) negativity, respectively. Among VGPR or better, there was no significant difference of modified progression-free survival (mPFS, hazard ratio [HR] 1.00, 95% confidence interval [CI] 0.69-1.44) or duration of response (DOR) (HR 1.02, 95%CI 0.68-1.53). Among relapsed/refractory MM (RRMM) achieving MRD negativity, late responders had significantly longer mPFS (p = 0.038) and DOR (p = 0.043). These results support that for patients who failed to achieve an early response to daratumumab, therapies should be continued with the goal of achieving ongoing and stepwise improvement of response.

Management of adverse events in patients with acute myeloid leukemia in remission receiving oral azacitidine: experience from the phase 3 randomized QUAZAR AML-001 trial

Background

Most older patients with acute myeloid leukemia (AML) who attain morphologic remission with intensive chemotherapy (IC) will eventually relapse and post-relapse prognosis is dismal. In the pivotal QUAZAR AML-001 trial, oral azacitidine maintenance therapy significantly prolonged overall survival by 9.9 months (P < 0.001) and relapse-free survival by 5.3 months (P < 0.001) compared with placebo in patients with AML in first remission after IC who were not candidates for transplant. Currently, the QUAZAR AML-001 trial provides the most comprehensive safety information associated with oral azacitidine maintenance therapy. Reviewed here are common adverse events (AEs) during oral azacitidine treatment in QUAZAR AML-001, and practical recommendations for AE management based on guidance from international cancer consortiums, regulatory authorities, and the authors’ clinical experience treating patients in the trial.

Methods

QUAZAR AML-001 is an international, placebo-controlled randomized phase 3 study. Patients aged ≥ 55 years with AML and intermediate- or poor-risk cytogenetics at diagnosis, who had attained first complete remission (CR) or CR with incomplete blood count recovery (CRi) within 4 months before study entry, were randomized 1:1 to receive oral azacitidine 300 mg or placebo once-daily for 14 days in repeated 28-day cycles. Safety was assessed in all patients who received ≥ 1 dose of study drug.

Results

A total of 469 patients received oral azacitidine (n = 236) or placebo (n = 233). Median age was 68 years. Patients received a median of 12 (range 1–80) oral azacitidine treatment cycles or 6 (1–73) placebo cycles. Gastrointestinal AEs were common and typically low-grade. The most frequent grade 3–4 AEs during oral azacitidine therapy were hematologic events. AEs infrequently required permanent discontinuation of oral azacitidine (13%), suggesting they were effectively managed with use of concomitant medications and oral azacitidine dosing modifications.

Conclusion

Oral azacitidine maintenance had a generally favorable safety profile. Prophylaxis with antiemetic agents, and blood count monitoring every other week, are recommended for at least the first 2 oral azacitidine treatment cycles, and as needed thereafter. Awareness of the type, onset, and duration of common AEs, and implementation of effective AE management, may maximize treatment adherence and optimize the survival benefits of oral azacitidine AML remission maintenance therapy.

Trial registration This trial is registered on clinicaltrials.gov: NCT01757535 as of December 2012.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01142-x.

Epidemiology of visceral mycoses in patients with acute leukemia and myelodysplastic syndrome: Analyzing the national autopsy database in Japan

Visceral mycoses (VM) are a deadly common infection in patients with acute leukemia and myelodysplastic syndrome (MDS). We retrospectively analyzed the data from the centralized "Annual Report of Autopsy Cases in Japan" that archives the national autopsy cases since 1989. Among the total of 175,615 archived autopsy cases, 7183 cases (4.1%) were acute leukemia and MDS patients. While VM was only found in 7756 cases (4.4% in total cases), we found VM had a disproportionally high prevalence among acute leukemia and MDS patients: 1562 VM cases (21.7%) and nearly sixfold higher in prevalence. Aspergillus spp. was the most predominant causative agent (45.0%), and Candida spp. was the second (22.7%) among confirmed single pathogen involved cases. The prevalence of Candida spp. infection decreased about 50% due to the widely use of fluconazole prophylaxis, which may skew toward doubling of the Mucormycetes incidence compared to 30 years ago. Complicated fungal infection (> one pathogen) was 11.0% in acute leukemia and MDS in 2015. It was 14.7 times higher than in other populations. Among 937 patients who received allogeneic hematopoietic cell transplantation (HCT), the prevalence of VM was 28.3% and 23.3% with GVHD. Aspergillus spp. was less prevalent, but Candida spp. was more associated with GVHD. Its prevalence remains stable. Although Aspergillus spp. was the primary causative agent, non-albicans Candida spp. was increasing as a breakthrough infection especially in GVHD cases. Complicated pathogen cases were more common in acute leukemia and MDS.

Risk of Non-Hodgkin's Lymphoma in HCV Patients in the United States Between 2013 and 2020: A Population-Based Study

Hepatitis C virus (HCV) is a significant healthcare problem affecting ~1% of the United States population. Meta-analyses of epidemiological studies reported a strong association between non-Hodgkin's lymphoma (NHL) and HCV. Direct oncogenic properties of HCV proteins and chronic antigenic stimulation are possible etiologies. We explored if NHL's prevalence has changed since older HCV therapy based on interferon that shared antiviral and anti-lymphoma properties was replaced with interferon-free direct-acting antivirals (DAA). We reviewed data from a nationwide database (Explorys, IBM) that aggregates records from 26 health-care-systems. We identified patients with chronic hepatitis C infection between June 2013 and June 2020. The control group was gender, race, and age-matched HCV-negative population. Statistical analysis used the odds ratio (OR) with P value <.001 for significance. There were 940 cases of NHL of 129,970 patients in the HCV group versus 107,480 cases of NHL of 37,961,970 in the control cohort [OR 2.6, 95% confidence interval (CI) 2.4-2.7]. A positive association was present for chronic lymphocytic leukemia, follicular lymphoma, marginal zone lymphoma, lymphoplasmacytic lymphoma, diffuse large B-cell lymphoma, Burkitt's lymphoma, non-Hodgkin T-cell lymphoma, and primary cutaneous T-cell lymphoma. There were no differences in Mantle cell lymphoma. The increased risk of HCV-associated lymphoma was persistent across genders, Caucasians and African-Americans, and age groups. While the risk of NHL in the HCV-negative population was higher in Caucasians than African-Americans (OR 1.8, 95% CI 1.7-1.8), the risk of HCV-associated NHL was not different. Further prospective studies examining the risk of HCV-associated lymphoma following DAA are warranted.

Targeting Two Antigens Associated with B-ALL with CD19-CD123 Compound Car T Cell Therapy

The recent FDA approval of the first CAR immunotherapy marks a watershed moment in the advancement toward a cure for cancer. CD19 CAR treatment for B cell acute lymphocytic leukemia has achieved unprecedented remission rates. However, despite success in treating previously relapsed and refractory patients, CD19 CAR faces similar challenges as traditional chemotherapy, in that malignancy can adapt and overcome treatment. The emergence of both antigen positive and negative blasts after CAR treatment represents a need to bolster current CAR approaches. Here, we report on the anti-tumor activity of a CAR T cell possessing 2 discrete scFv domains against the leukemic antigens CD19 and CD123. We determined that the resulting compound CAR (cCAR) T cell possesses consistent, potent, and directed cytotoxicity against each target antigen population both in vitro and in vivo. Our findings indicate that targeting CD19 and CD123 on B-ALL cells may be an effective strategy for augmenting the response against leukemic blasts and reducing rates of relapse.

Metabolic networks of the human gut microbiota

The human gut microbiota controls factors that relate to human metabolism with a reach far greater than originally expected. Microbial communities and human (or animal) hosts entertain reciprocal exchanges between various inputs that are largely controlled by the host via its genetic make-up, nutrition and lifestyle. The composition of these microbial communities is fundamental to supply metabolic capabilities beyond those encoded in the host genome, and contributes to hormone and cellular signalling that support the dynamic adaptation to changes in food availability, environment and organismal development. Poor functional exchange between the microbial communities and their human host is associated with dysbiosis, metabolic dysfunction and disease. This review examines the biology of the dynamic relationship between the reciprocal metabolic state of the microbiota-host entity in balance with its environment (i.e. in healthy states), the enzymatic and metabolic changes associated with its imbalance in three well-studied diseases states such as obesity, diabetes and atherosclerosis, and the effects of bariatric surgery and exercise.

A Phase II Trial of Imatinib Mesylate as Maintenance Therapy for Patients With Newly Diagnosed C-kit-positive Acute Myeloid Leukemia

INTRODUCTION

Adults with acute myeloid leukemia (AML) have a high rate of remission; however, more than 50% relapse. C-kit is expressed in approximately 60% of patients with de novo AML and represents a potential therapeutic target.

MATERIALS AND METHODS

Patients with newly diagnosed AML received 12 months of imatinib mesylate as maintenance therapy after the completion of post-remission therapy. The primary objective was to determine whether this approach improved progression-free survival (defined as no relapse and no death) compared with historical controls.

RESULTS

The median progression-free survival of patients < 60 years of age was 52.1 months (historical control, 13 months) and for patients ≥ 60 years of age was 10.7 months (historical control, 8 months). The median level of AF1q expression was high (9.59), and 84% of patients had moderate or high levels of drug-resistance factors.

CONCLUSIONS

Imatinib maintenance therapy may improve the outcome of newly diagnosed patients with AML who are < 60 years of age.

The Oncogene AF1Q is Associated with WNT and STAT Signaling and Offers a Novel Independent Prognostic Marker in Patients with Resectable Esophageal Cancer

AF1q impairs survival in hematologic and solid malignancies. AF1q expression is associated with tumor progression, migration, and chemoresistance, and acts as a transcriptional co-activator in WNT and STAT signaling. This study evaluates the role of AF1q in patients with resectable esophageal cancer (EC). A total of 278 patients operated on for esophageal cancer were retrospectively included, and the expression of AF1q, CD44, and pYSTAT3 was analyzed following immunostaining. Quantified data were processed to correlational and survival analysis. In EC patients, an elevated expression of AF1q was associated with CD44 (p = 0.004), and pYSTAT3 (p = 0.0002). High AF1q expression in primary tumors showed high AF1q expression in the corresponding lymph nodes (p= 0.016). AF1q expression was higher after neoadjuvant therapy (p= 0.0002). Patients with AF1q-positive EC relapsed and died earlier compared to patients with AF1q-negative EC (disease-free survival (DFS), p= 0.0005; disease-specific survival (DSS), p= 0.003); in the multivariable Cox regression model, AF1q proved to be an independent prognostic marker (DFS, p= 0.01; DSS, p= 0.03). AF1q is associated with WNT and STAT signaling; it impairs and independently predicts DFS and DSS in patients with resectable EC. The testing of AF1q could facilitate prognosis estimation and provide a possibility of identifying the patients responsive to the therapeutic blockade of its oncogenic downstream targets.

Recombinant expression and purification of AF1q and its interaction with T-cell Factor 7

The protein ALL1 fused from chromosome 1q (AF1q) is overexpressed in a variety of cancers and acts to activate several signaling pathways that lead to oncogenesis. For example, AF1q has been shown to interact with T-cell Factor 7 (TCF7; also known as TCF1) from the Wnt/β-catenin pathway resulting in the transcriptional activation of the CD44 and the enhancement of breast cancer metastasis. Despite the importance of AF1q in facilitating oncogenesis and metastasis, the structural and biophysical properties of AF1q remain largely unexplored due to the absence of a viable method for producing recombinant protein. Here, we report the overexpression of AF1q in E. coli as a fusion to a N-terminal His₆-tag, which forms inclusion bodies (IBs) during expression. The AF1q protein was purified from IBs under denaturing conditions by immobilized metal affinity chromatography followed by a successful one-step dialysis refolding. Refolded AF1q was further purified to homogeneity by gel filtration chromatography resulting in an overall yield of 35 mg/L culture. Our nuclear magnetic resonance (NMR) and analytical ultracentrifugation (AUC) measurements reveal AF1q interacts with TCF7, specifically with TCF7's high-mobility group (HMG) domain (residues 154-237), which is, to our knowledge, the first biophysical characterization of the AF1q and TCF7 interaction.

AF1q inhibited T cell attachment to breast cancer cell by attenuating Intracellular Adhesion Molecule-1 expression

Aim:

To investigate whether AF1q, overexpressed in metastatic cells compared with the primary tumor cells, plays a pivotal role in breast cancer metastasis.

Methods:

To investigate whether AF1q has a responsibility in the acquisition of a metastatic phenotype, we performed RNA-sequencing (RNA-Seq) to identify the gene signature and applied the Metacore direct interactions network building algorithm with the top 40 amplicons of RNA-Seq.

Results:

Most genes were directly linked with intercellular adhesion molecule-1 (ICAM-1). Likewise, we identified that ICAM-1 expression is attenuated in metastatic cells compared to primary tumor cells. Moreover, overexpression of AF1q attenuated ICAM-1 expression, whereas suppression of AF1q elicited the opposite effect. AF1q had an effect on ICAM-1 promoter region and regulated its transcription. Decreased ICAM-1 expression affected the attachment of T cells to a breast cancer cell monolayer. We confirmed the finding by performing the analysis on Burkitt’s lymphoma.

Conclusion:

Attenuation of ICAM-1 by AF1q on tumor cells disadvantages host anti-tumor defenses through the trafficking of lymphocytes, which affects tumor progression and metastasis.

Pathobiological Pseudohypoxia as a Putative Mechanism Underlying Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are heterogeneous hematopoietic disorders that are incurable with conventional therapy. Their incidence is increasing with global population aging. Although many genetic, epigenetic, splicing, and metabolic aberrations have been identified in patients with MDS, their clinical features are quite similar. Here, we show that hypoxia-independent activation of hypoxia-inducible factor 1α (HIF1A) signaling is both necessary and sufficient to induce dysplastic and cytopenic MDS phenotypes. The HIF1A transcriptional signature is generally activated in MDS patient bone marrow stem/progenitors. Major MDS-associated mutations (Dnmt3a, Tet2, Asxl1, Runx1, and Mll1) activate the HIF1A signature. Although inducible activation of HIF1A signaling in hematopoietic cells is sufficient to induce MDS phenotypes, both genetic and chemical inhibition of HIF1A signaling rescues MDS phenotypes in a mouse model of MDS. These findings reveal HIF1A as a central pathobiologic mediator of MDS and as an effective therapeutic target for a broad spectrum of patients with MDS.Significance: We showed that dysregulation of HIF1A signaling could generate the clinically relevant diversity of MDS phenotypes by functioning as a signaling funnel for MDS driver mutations. This could resolve the disconnection between genotypes and phenotypes and provide a new clue as to how a variety of driver mutations cause common MDS phenotypes. Cancer Discov; 8(11); 1438-57. ©2018 AACR. See related commentary by Chen and Steidl, p. 1355 This article is highlighted in the In This Issue feature, p. 1333.

The Emerging Link Between the Complement Cascade and Purinergic Signaling in Stress Hematopoiesis

Innate immunity plays an important role in orchestrating the immune response, and the complement cascade (ComC) is a major component of this ancient defense system, which is activated by the classical-, alternative-, or mannan-binding lectin (MBL) pathways. However, the MBL-dependent ComC-activation pathway has been somewhat underappreciated for many years; recent evidence indicates that it plays a crucial role in regulating the trafficking of hematopoietic stem/progenitor cells (HSPCs) by promoting their egress from bone marrow (BM) into peripheral blood (PB). This process is initiated by the release of danger-associated molecular patterns (DAMPs) from BM cells, including the most abundant member of this family, adenosine triphosphate (ATP). This nucleotide is well known as a ubiquitous intracellular molecular energy source, but when secreted becomes an important extracellular nucleotide signaling molecule and mediator of purinergic signaling. What is important for the topic of this review, ATP released from BM cells is recognized as a DAMP by MBL, and the MBL-dependent pathway of ComC activation induces a state of "sterile inflammation" in the BM microenvironment. This activation of the ComC by MBL leads to the release of several potent mediators, including the anaphylatoxins C5a and _desArgC5a, which are crucial for egress of HSPCs into the circulation. In parallel, as a ligand for purinergic receptors, ATP affects mobilization of HSPCs by activating other pro-mobilizing pathways. This emerging link between the release of ATP, which on the one hand is an activator of the MBL pathway of the ComC and on the other hand is a purinergic signaling molecule, will be discussed in this review. This mechanism plays an important role in triggering defense mechanisms in response to tissue/organ injury but may also have a negative impact by triggering autoimmune disorders, aging of HSPCs, induction of myelodysplasia, and graft-versus-host disease after transplantation of histoincompatible hematopoietic cells.

MLLT11/AF1q boosts oncogenic STAT3 activity through Src-PDGFR tyrosine kinase signaling

Constitutive STAT3 activation by tyrosine phosphorylation of mutated or amplified tyrosine kinases (pYSTAT3) is critical for cancer initiation, progression, invasion, and motility of carcinoma cells. We showed that AF1q is associated with STAT3 signaling in breast cancer cells. In xenograft models, enhanced AF1q expression activated STAT3 and promoted tumor growth and metastasis in immunodeficient NSG mice. The cytokine secretory phenotype of MDA-MB-231LN breast cancer cells with altered AF1q expression revealed changes in expression of platelet-derived growth factor subunit B (PDGF-B). AF1q-induced PDGF-B stimulated motility, migration, and invasion of MDA-MB-231LN cells, and AF1q up-regulated platelet-derived growth factor receptor (PDGFR) signaling. Further, AF1q-induced PDGFR signaling enhanced STAT3 activity through Src kinase activation, which could be blocked by the Src kinase inhibitor PP1. Moreover, AF1q up-regulated tyrosine kinase signaling through PDGFR signaling, which was blockable by imatinib. In conclusion, we demonstrated that enhanced AF1q expression contributes to persistent and oncogenic pYSTAT3 levels in invasive carcinoma cells by activating Src kinase through activation of the PDGF-B/PDGFR cascade. Therefore, AF1q plays an essential role as a cofactor in PDGF-B-driven STAT3 signaling.

Targeting T-cell malignancies using anti-CD4 CAR NK-92 cells

Peripheral T-cell lymphomas (PTCLs) are a group of very aggressive non-Hodgkin's lymphomas (NHLs) with poor prognoses and account for a majority of T-cell malignancies. Overall, the standard of care for patients with T-cell malignancies is poorly established, and there is an urgent clinical need for a new approach. As demonstrated in B-cell malignancies, chimeric antigen receptor (CAR) immunotherapy provides great hope as a curative treatment regimen. Because PTCLs develop from mature T-cells, these NHLs are commonly CD4+, and CD4 is highly and uniformly expressed. Therefore, CD4 is an ideal target for PTCL CAR immunotherapy. To that effect, we created a robust third-generation anti-CD4 CAR construct (CD4CAR) and introduced it into clonal NK cells (NK-92). CD4CAR NK-92 cells specifically and robustly eliminated diverse CD4+ human T-cell leukemia and lymphoma cell lines (KARPAS-299, CCRF-CEM, and HL60) and patient samples ex vivo. Furthermore, CD4CAR NK-92 cells effectively targeted KARPAS-299 cells in vivo that modeled difficult-to-access lymphoma nodules, significantly prolonging survival. In our study, we present novel targeting of CD4 using CAR-modified NK cells, and demonstrate efficacy. Combined, our data support CD4CAR NK cell immunotherapy as a potential new avenue for the treatment of PTCLs and CD4+ T-cell malignancies.

Early mixed T-cell chimerism is predictive of pediatric AML or MDS relapse after hematopoietic stem cell transplant

Patients with acute myeloid leukemia (AML) who relapse after hematopoietic stem cell transplantation (HCT) have dismal outcomes. Our ability to predict those at risk for relapse is limited. We examined chimerism trends post-HCT in 63 children who underwent HCT for AML or myelodysplastic syndrome (MDS). Mixed T-cell chimerism at engraftment and absence of chronic graft versus host disease (cGVHD) were associated with relapse (P = 0.04 and P = 0.02, respectively). Mixed T-cell chimerism at engraftment was predictive in patients without cGVHD (P = 0.03). Patients with engraftment mixed T-cell chimerism may warrant closer disease monitoring and consideration for early intervention.

Abstract 3969: AF1q/Mllt11 regulates the expression of intercellular adhesion molecule-1 in breast cancer

Intercellular adhesion molecule-1 (ICAM-1) is a cell surface glycoprotein in the immunoglobulin superfamily. ICAM-1 expression is frequently observed on many cell types including endothelial cells and different cancer cell entities. Experimental data strongly indicate that ICAM-1 can activate intracellular signaling pathways in cancer cells leading to enhanced cell motility, invasion and metastasis. In clinical investigation, however, ICAM-1 expression was negatively correlated to tumor size, lymph node metastasis, and tumor infiltration. Also, there was improved relapse-free and overall survival in patients with ICAM-1 positive tumors. Yet, the function of ICAM-1 expression during malignant progression in breast cancer patients is not understood clearly. However, ICAM-1 is still considered as a breast cancer target and biomarker may lead to the development of a new strategy and platform for breast cancer patients.

We observed AF1q, a metastasis enhancer, is only expressed in metastatic cells, MDA-MB-231LN (invasive sub line from MDA-MB-231), not in the primary tumor cells. To investigate whether AF1q has a responsibility in acquisition of metastatic phenotype, we performed RNA-Seq and applied the Metacore network building algorithm. Intriguingly, most genes were directly linked with Intercellular Adhesion Molecule-1 (ICAM-1). Likewise, we identified that ICAM-1 expression is attenuated in MDA-MB-231LN compared to MDA-MB-231. Moreover, the expression of ICAM-1 was negatively regulated, when AF1q was overexpressed in MDA-MD-231LN. Suppressed endogenous AF1q by shRNA could effectively increase the ICAM-1 expression. Attenuation of ICAM-1 by AF1q on tumor cells would disadvantage host anti-tumor defenses by trafficking of lymphocytes, which affect tumor progression and metastasis.

We observed that NF-κB activity which regulates ICAM-1 expression is attenuated in response to AF1q expression in breast cancer cells. Published reports shown that Wnt/β-catenin negatively regulates NF-κB activity through protein-protein interaction in colon and breast cancer cells. Previously, we reported that AF1q enhance the TCF7/LEF/β-catenin complex binding affinity as a cofactor. Structurally, AF1q has highly acidic peptide regions highly conserved between species that fulfill the criteria for an acidic blob, a typical feature for cofactors. When we performed immunoprecipitation with NF-κB antibody in MDA-MB-231LN overexpressed AF1q, we observed that β-catenin and AF1q were pulled down together. However, it is not clear yet whether AF1q promote protein interaction between β-catenin and NF-κB. These results suggest that activated β-catenin by AF1q would archive higher affinity to bind with NF-κB and thereby attenuate ICAM-1 expression.

Citation Format: Jino Park, Soojin Kim, William Tse. AF1q/Mllt11 regulates the expression of intercellular adhesion molecule-1 in breast 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 3969. doi:10.1158/1538-7445.AM2017-3969

Abstract 4463: The coactivator oncogene AF1Q associates with STAT3 activation downstream of MET action in gastro-esophageal cancer patients

AF1Q was initially identified as an oncogene in acute myeloid leukemia. In breast cancer, AF1q mediates tumor progression by boosting STAT3-signalling. In addition, AF1q enhances wnt-signalling resulting in transcriptional activation of CD44 and promotes tumor cell proliferation, migration and chemo-resistance. In gastrointestinal malignancies both pathways are linked to enhanced MET tyrosine kinase receptor action, accelerating tumor progression and metastases. We showed that Af1q overexpression in the gastro-esophageal cancer cell lines SK-GT-4, FLO-1 and OE33 led to increased sphere formation and increased invasive capacity in the case of FLO-1 and OE33. We investigated the role of AF1q in a retrospective collective of 460 resected gastro-esophageal cancer specimens (74.3% adenocarcinomas (AC), 25.7% esophageal squamous cell cancers (SCC)). With respect to topographic location, 40.4% of tumors were esophageal (EC), 20% gastro-esophageal (GEC) and 39.6% gastric cancers (GC). Immunohistochemistry revealed overexpression of AF1q in 205, and of CD44 in 114 patient tumor samples. AF1q overexpression was found more often in EC/GEC as compared to GC (p=0.007) and associated with HER2 (p=0.035), pySTAT3 (p&lt;0.001) and MET (p=0.004) expression as well as neoadjuvant chemotherapy (p&lt;0.001). AF1q and CD44 overexpression correlated in the overall group (p&lt;0.001) and in AC (p&lt;0.001). In SCC CD44 was expressed more frequently compared to AC (p&lt;0.001). Analysis of the matched primary and metastatic tumors revealed that primary AF1q-positive tumor samples were largely overlapping with AF1q-positive tumors lymph node metastases (23/32) and distant metastases (6/7). AF1q overexpression correlated with shorter disease free survival (DFS) (p=0.003) and shorter disease specific survival (DSS) (p=0.036), but overall survival (OS) was similar (p=0.117). In a subgroup analysis a shorter OS was observed in EC/GEC (p=0.03, log rank test). In a Cox regression model AF1q and CD44 expression was associated with shorter DFS (p&lt;0.001 and p=0.025) and DSS (p=0.005 and p=0.035), but OS remained unchanged. Prognostic significance was limited to AF1q (p=0.003 and p=0.04, respectively). We conclude, that AF1q overexpression is associated with progression and metastases in GEC. AF1q and downstream pathway markers such as pySTAT3- as well as CD44 and MET are linked with AF1q expression. Therefore we propose AF1q as a novel prognostic marker for GECs.

Citation Format: Elisabeth S. Gruber, Peter Birner, Olaf Merkel, Michael M. Bergmann, Sebastian F. Schoppmann, Jino Park, Richard Moriggl, William Tse, Lukas Kenner. The coactivator oncogene AF1Q associates with STAT3 activation downstream of MET action in gastro-esophageal cancer patients [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 4463. doi:10.1158/1538-7445.AM2017-4463

Synergistic cell death in FLT3-ITD positive acute myeloid leukemia by combined treatment with metformin and 6-benzylthioinosine

Current therapy for acute myeloid leukemia (AML) primarily includes high-dose cytotoxic chemotherapy with or without allogeneic stem cell transplantation. Targeting unique cellular metabolism of cancer cells is a potentially less toxic approach. Monotherapy with mitochondrial inhibitors like metformin have met with limited success since escape mechanisms such as increased glycolytic ATP production, especially in hyperglycemia, can overcome the metabolic blockade. As an alternative strategy for metformin therapy, we hypothesized that the combination of 6-benzylthioinosine (6-BT), a broad-spectrum metabolic inhibitor, and metformin could block this drug resistance mechanism. Metformin treatment alone resulted in significant suppression of ROS and mitochondrial respiration with increased glycolysis accompanied by modest cytotoxicity (10-25%). In contrast, 6-BT monotherapy resulted in inhibition of glucose uptake, decreased glycolysis, and decreased ATP with minimal changes in ROS and mitochondrial respiration. The combination of 6-BT with metformin resulted in significant cytotoxicity (60-70%) in monocytic AML cell lines and was associated with inhibition of FLT3-ITD activated STAT5 and reduced c-Myc and GLUT-1 expression. Therefore, although the anti-tumor and metabolic effects of metformin have been limited by the metabolic reprogramming within cells, the novel combination of 6-BT and metformin targets this bypass mechanism resulting in reduced glycolysis, STAT5 inhibition, and increased cell death.

Methotrexate-associated primary cutaneous CD30-positive cutaneous T-cell lymphoproliferative disorder: a case illustration and a brief review

Methotrexate (MTX) is a commonly used anti-metabolite agent. Increased risk of lymphoproliferative disorders (LPD) in patients with rheumatoid arthritis (RA) has been documented with the prolonged use of immunosuppressive medications such as MTX. This is thought to be the result of immune dysregulation and/or chronic immune stimulation. Most cases of LPDs regress following withdrawal of the offending immunosuppressive agent. We present an interesting and rare case of CD30 and EBV positive CD8 primary cutaneous anaplastic large cell lymphoma (PC-ALCL) in a 66-year-old African American woman. Patient had been on MTX for rheumatoid arthritis (RA) which was stopped after the patient was evaluated at our institution. Patient had an incredible response to stopping immunosuppression with spontaneous regression of skin lesions and disappearance of clonal malignant cell population as evidenced on serial biopsy specimens. Primary cutaneous CD30+ LPDs constitute about 30% of the primary cutaneous T-cell lymphomas (CTLs) and includes entities such as lymphomatoid papulosis (LyP), primary cutaneous anaplastic large cell lymphoma (PC-ALCL) and other CD30+ borderline LPDs. Histopathological criteria in addition to CD30 positivity is important for identification of these conditions. Treatment options include "wait and see", phototherapy, radiotherapy, topical agents, systemic therapy and surgical resection. Prognosis is excellent and most cases resolve spontaneously on withdrawal of immunosuppression. Refractory cases may require aggressive local treatment or systemic therapy. Brentuximab Vedontin, an anti-CD30 antibody drug conjugate (ADC), may provide additional therapeutic option in refractory cases.

AF1q is a novel TCF7 co-factor which activates CD44 and promotes breast cancer metastasis

AF1q is an MLL fusion partner that was identified from acute myeloid leukemia (AML) patients with t (1; 11) (q21; q23) chromosomal abnormality. The function of AF1q is not yet fully known, however, elevated AF1q expression is associated with poor clinical outcomes in various malignancies. Here, we show that AF1q specifically binds to T-cell-factor-7 (TCF7) in the Wnt signaling pathway and results in transcriptional activation of CD44 as well as multiple downstream targets of the TCF7/LEF1. In addition, enhanced AF1q expression promotes breast cancer cell proliferation, migration, mammosphere formation, and chemo-resistance. In xenograft models, enforced AF1q expression in breast cancer cells also promotes liver metastasis and lung colonization. In a cohort of 63 breast cancer patients, higher percentages of AF1q-positive cancer cells in primary sites were associated with significantly poorer overall survival (OS), disease-free survival (DFS), and brain metastasis-free survival (b-MFS). Using paired primary/metastatic samples from the same patients, we demonstrate that AF1q-positive breast cancer cells become dynamically dominant in the metastatic sites compared to the primary sites. Our findings indicate that breast cancer cells with a hyperactive AF1q/TCF7/CD44 regulatory axis in the primary sites may represent "metastatic founder cells" which have invasive properties.

Type B lactic acidosis: a rare but life threatening hematologic emergency. A case illustration and brief review

Major strides have been made in improving the treatment of medical emergencies associated with malignancies. Nonetheless, metabolic emergencies in cancer patients can often times be life-threatening. Type B lactic acidosis is a rare but potentially fatal paraneoplastic phenomenon that has been described in association with hematologic and solid malignancies and portends a poor prognosis if not rapidly recognized and treated. It is believed that this occurs as a result of cancer cells switching their glucose metabolism from an oxidative oxygen- dependent pathway towards a glycolytic phenotype, also known as the "Warburg effect". Though rare, it is important to consider this entity in the differential diagnosis of type B lactic acidosis since prompt identification and treatment may help improve outcomes in this otherwise fatal process. We present a case of type B lactic acidosis in a patient with chronic lymphocytic leukemia along with a brief review of the literature.

Wnt signaling is involved in 6-benzylthioinosine-induced AML cell differentiation

Background

We previously demonstrated that 6-benzylthioinosine (6-BT) could induce the differentiation of a subset of acute myeloid leukemia (AML) cell lines and primary AML cells regardless of their cytogenetics. In this study we investigated whether Wnt signaling pathways played roles in 6-BT-induced differentiation of AML cells.

Methods

We induced differentiation of HL-60 leukemic cells and primary AML cells in vitro using 6-BT. Real-time PCR (qPCR), western blot, and luciferase assays were used to examine the molecules’ expression and biological activity in canonical and noncanonical Wnt signaling pathways. AML cell differentiation was measured by the Nitroblue tetrozolium (NBT) reduction assay.

Results

6-BT regulated the expression of both canonical and non-canonical Wnt signaling molecules in HL-60 cells. Both 6-BT and all-trans-retinoic-acid (ATRA) reduced canonical Wnt signaling and activated noncanonical Wnt/Ca²⁺ signaling in HL-60 cells. Pre-treatment of HL-60 cells with an inhibitor of glycogen synthase kinase-3β (GSK-3β), which activated canonical Wnt signaling, partly abolished the differentiation of HL-60 cells induced by 6-BT. Pre-treatment of HL-60 cells with an inhibitor of protein kinase C (PKC), resulting in inactivation of non-canonical Wnt/Ca²⁺ signaling, abolished 6-BT-induced differentiation of HL-60 cells. Several molecules in the non-canonical Wnt/Ca²⁺ pathway were detected in bone marrow samples from AML patients, and the expression of FZD4, FZD5, Wnt5a and RHOU were significantly reduced in newly diagnosed AML samples compared with normal controls.

Conclusions

Both canonical and non-canonical Wnt signaling were involved in 6-BT-induced differentiation of HL-60 cells, and played opposite roles in this process. Wnt signaling could be involved in the pathogenesis of AML not only by regulating self-renewal of hematopoietic stem cells, but also by playing a role in the differentiation of AML cells.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-886) contains supplementary material, which is available to authorized users.

Strategies of dose escalation in the treatment of locally advanced non-small cell lung cancer: image guidance and beyond

Radiation dose in the setting of chemo-radiation for locally advanced non-small cell lung cancer (NSCLC) has been historically limited by the risk of normal tissue toxicity and this has been hypothesized to correlate with the poor results in regard to local tumor recurrences. Dose escalation, as a means to improve local control, with concurrent chemotherapy has been shown to be feasible with three-dimensional conformal radiotherapy in early phase studies with good clinical outcome. However, the potential superiority of moderate dose escalation to 74 Gy has not been shown in phase III randomized studies. In this review, the limitations in target volume definition in previous studies; and the factors that may be critical to safe dose escalation in the treatment of locally advanced NSCLC, such as respiratory motion management, image guidance, intensity modulation, FDG-positron emission tomography incorporation in the treatment planning process, and adaptive radiotherapy, are discussed. These factors, along with novel treatment approaches that have emerged in recent years, are proposed to warrant further investigation in future trials in a more comprehensive and integrated fashion.

Role of H-Ras/ERK signaling in carbon nanotube-induced neoplastic-like transformation of human mesothelial cells

Rapid development and deployment of engineered nanomaterials such as carbon nanotubes (CNTs) in various commercial and biomedical applications have raised concerns about their potential adverse health effects, especially their long-term effects which have not been well addressed. We demonstrated here that prolonged exposure of human mesothelial cells to single-walled CNT (SWCNT) induced neoplastic-like transformation as indicated by anchorage-independent cell growth and increased cell invasiveness. Such transformation was associated with an up-regulation of H-Ras and activation of ERK1/2. Downregulation of H-Ras by siRNA or inactivation of ERK by chemical inhibitor effectively inhibited the aggressive phenotype of SWCNT-exposed cells. Integrin alpha V and cortactin, but not epithelial-mesenchymal transition (EMT) transcriptional regulators, were up-regulated in the SWCNT-exposed cells, suggesting their role in the aggressive phenotype. Cortactin expression was shown to be controlled by the H-Ras/ERK signaling. Thus, our results indicate a novel role of H-Ras/ERK signaling and cortactin in the aggressive transformation of human mesothelial cells by SWCNT.

Geriatric oncology for the 21st century: a call for action

The recently released Institute of Medicine report further emphasizes the need for the oncology community to optimize care of older patients with cancer.

Sibling donor and recipient immune modulation with atorvastatin for the prophylaxis of acute graft-versus-host disease

PURPOSE

Graft-versus-host disease (GVHD) is major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Atorvastatin is a potent immunomodulatory agent that holds promise as a novel and safe agent for acute GVHD prophylaxis.

PATIENTS AND METHODS

We conducted a phase II trial to evaluate the safety and efficacy of atorvastatin administration for GVHD prophylaxis in both adult donors and recipients of matched sibling allogeneic HCT. Atorvastatin (40 mg per day orally) was administered to sibling donors, starting 14 to 28 days before the anticipated first day of stem-cell collection. In HCT recipients (n = 30), GVHD prophylaxis consisted of tacrolimus, short-course methotrexate, and atorvastatin (40 mg per day orally).

RESULTS

Atorvastatin administration in healthy donors and recipients was not associated with any grade 3 to 4 adverse events. Cumulative incidence rates of grade 2 to 4 acute GVHD at days +100 and +180 were 3.3% (95% CI, 0.2% to 14.8%) and 11.1% (95% CI, 2.7% to 26.4%), respectively. One-year cumulative incidence of chronic GVHD was 52.3% (95% CI, 27.6% to 72.1%). Viral and fungal infections were infrequent. One-year cumulative incidences of nonrelapse mortality and relapse were 9.8% (95% CI, 1.4% to 28%) and 25.4% (95% CI, 10.9% to 42.9%), respectively. One-year overall survival and progression-free survival were 74% (95% CI, 58% to 96%) and 65% (95% CI, 48% to 87%), respectively. Compared with baseline, atorvastatin administration in sibling donors was associated with a trend toward increased mean plasma interleukin-10 concentrations (5.6 v 7.1 pg/mL; P = .06).

CONCLUSION

A novel two-pronged strategy of atorvastatin administration in both donors and recipients of matched sibling allogeneic HCT seems to be a feasible, safe, and potentially effective strategy to prevent acute GVHD.

Pancytopenia related to dental adhesive in a young patient

Copper deficiency resulting in hypocupremia is a rare cause of pancytopenia associated with a neurological syndrome. Hypocupremia may also occur as a consequence of excessive oral zinc consumption as described by Brewer et al and several other groups. Dental fixatives have been described as a potential source of hyperzincemia in patients. Despite the recently modified dental fixatives with safer zinc content, zinc poisoning results in hypocupremia secondary to inappropriate use of them can still happen and more likely be misdiagnosed. We describe a case of a patient with pancytopenia who was diagnosed with severe aplastic anemia and hypocellular myelodysplastic syndrome and was referred to us for consideration of bone marrow transplantation.

Requirement for frzb and fzd7a in cranial neural crest convergence and extension mechanisms during zebrafish palate and jaw morphogenesis

Regulation of convergence and extension by wnt-frizzled signaling is a common theme in embryogenesis. This study examines the functional requirements of frzb and fzd7a in convergence and extension mechanisms during craniofacial development. Using a morpholino knockdown approach, we found that frzb and fzd7a are dispensable for directed migration of the bilateral trabeculae, but necessary for the convergence and extension of the palatal elements, where the extension process is mediated by chondrocyte proliferation, morphologic change and intercalation. In contrast, frzb and fzd7a are required for convergence of the mandibular prominences, where knockdown of either frzb or fzd7a resulted in complete loss of lower jaw structures. Further, we found that bapx1 was specifically downregulated in the wnt9a/frzb/fzd7a morphants, while general neural crest markers were unaffected. In addition, expression of wnt9a and frzb was also absent in the edn-/- mutant. Notably, over-expression of bapx1 was sufficient to partially rescue mandibular elements in the wnt9a/frzb/fzd7a morphants, demonstrating genetic epistasis of bapx1 acting downstream of edn1 and wnt9a/frzb/fzd7a in lower jaw development. This study underscores the important role of wnt-frizzled signaling in convergence and extension in palate and craniofacial morphogenesis, distinct regulation of upper vs. lower jaw structures, and integration of wnt-frizzled with endothelin signaling to coordinate shaping of the facial form.

Peripheral blood stem cell mobilization in multiple myeloma patients treat in the novel therapy-era with plerixafor and G-CSF has superior efficacy but significantly higher costs compared to mobilization with low-dose cyclophosphamide and G-CSF

Studies comparing the efficacy and cost of peripheral blood stem and progenitor cells mobilization with low-dose cyclophosphamide (LD-CY) and granulocyte-colony stimulating factor (G-CSF) against plerixafor and G-CSF, in multiple myeloma (MM) patients treated in the novel therapy-era are not available. Herein, we report mobilization outcomes of 107 patients who underwent transplantation within 1-year of starting induction chemotherapy with novel agents. Patients undergoing mobilization with LD-CY (1.5 gm/m(2)) and G-CSF (n = 74) were compared against patients receiving plerixafor and G-CSF (n = 33). Compared to plerixafor, LD-CY was associated with a significantly lower median peak peripheral blood CD34+ cell count (68/µL vs. 36/µL, P = 0.048), and lower CD34+ cell yield on day 1 of collection (6.9 × 10(6)/kg vs. 2.4 × 10(6)/kg, P = 0.001). Six patients (8.1%) in the LD-CY group experienced mobilization failure, compared to none in the plerixafor group. The total CD34+ cell yield was significantly higher in the plerixafor group (median 11.6 × 10(6)/kg vs. 7 × 10(6)/kg; P-value = 0.001). Mobilization with LD-CY was associated with increased (albeit statistically non-significant) episodes of febrile neutropenia (5.4% vs. 0%; P = 0.24), higher use of intravenous antibiotics (6.7% vs. 3%; P = 0.45), and need for hospitalizations (9.4% vs. 3%; P = 0.24). The average total cost of mobilization in the plerixafor group was significantly higher compared to the LD-CY group ($28,980 vs. $19,626.5 P-value < 0.0001). In conclusion, in MM plerixafor-based mobilization has superior efficacy, but significantly higher mobilization costs compared to LD-CY mobilization. Our data caution against the use of LD-CY in MM patients for mobilization, especially after induction with lenalidomide-containing regimens.

Regulation of apoptosis by Bcl-2 cysteine oxidation in human lung epithelial cells

Bcl-2 interacts with ERK to suppress apoptosis. Hydrogen peroxide disrupts the interaction through Bcl-2 cysteine oxidation, which promotes apoptosis. These findings provide a novel redox regulatory mechanism that controls apoptosis via Bcl-2 cysteine oxidation, which could aid in the understanding of pathogenesis under oxidative stress conditions.

Hydrogen peroxide is a key mediator of oxidative stress known to be important in various cellular processes, including apoptosis. B-cell lymphoma-2 (Bcl-2) is an oxidative stress–responsive protein and a key regulator of apoptosis; however, the underlying mechanisms of oxidative regulation of Bcl-2 are not well understood. The present study investigates the direct effect of H₂O₂ on Bcl-2 cysteine oxidation as a potential mechanism of apoptosis regulation. Exposure of human lung epithelial cells to H₂O₂ induces apoptosis concomitant with cysteine oxidation and down-regulation of Bcl-2. Inhibition of Bcl-2 oxidation by antioxidants or by site-directed mutagenesis of Bcl-2 at Cys-158 and Cys-229 abrogates the effects of H₂O₂ on Bcl-2 and apoptosis. Immunoprecipitation and confocal microscopic studies show that Bcl-2 interacts with mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2 [ERK1/2]) to suppress apoptosis and that this interaction is modulated by cysteine oxidation of Bcl-2. The H₂O₂-induced Bcl-2 cysteine oxidation interferes with Bcl-2 and ERK1/2 interaction. Mutation of the cysteine residues inhibits the disruption of Bcl-2–ERK complex, as well as the induction of apoptosis by H₂O₂. Taken together, these results demonstrate the critical role of Bcl-2 cysteine oxidation in the regulation of apoptosis through ERK signaling. This new finding reveals crucial redox regulatory mechanisms that control the antiapoptotic function of Bcl-2.

EGFR inhibition in non-small cell lung cancer: current evidence and future directions

EGFR inhibition has emerged to be an important strategy in the treatment of non-small cell lung cancer (NSCLC). Small molecule tyrosine kinase inhibitors (TKIs) and mono-clonal antibodies (mAbs) to the EGFR have been tested in multiple large randomized phase III studies alone or combined with chemotherapy, as well as small phase I-II studies which investigated their efficacy as radiosensitizers when combined with radiotherapy. In this review, we described the current clinical outcome after treatment with EGFR TKIs and mAbs alone or combined with chemotherapy in advanced stage NSCLC, as well as the early findings in feasibility/phase I or II studies regarding to whether EGFR TKI or mAb can be safely and effectively combined with radiotherapy in the treatment of locally advanced NSCLC. Furthermore, we explore the potential predictive biomarkers for response to EGFR TKIs or mAbs in NSCLC patients based on the findings in the current clinical trials; the mechanisms of resistance to EGFR inhibition; and the strategies of augmenting the antitumor activity of the EGFR inhibitors alone or when combined with chemotherapy or radiotherapy.

Intensity modulated radiotherapy for sinonasal malignancies with a focus on optic pathway preservation

PURPOSE

To assess if intensity-modulated radiotherapy (IMRT) can possibly lead to improved local control and lower incidence of vision impairment/blindness in comparison to non-IMRT techniques when treating sinonasal malignancies; what is the most optimal dose constraints for the optic pathway; and the impact of different IMRT strategies on optic pathway sparing in this setting.

METHODS AND MATERIALS

A literature search in the PubMed databases was conducted in July, 2012.

RESULTS

Clinical studies on IMRT and 2D/3D (2 dimensional/3 dimensional) RT for sinonasal malignancies suggest improved local control and lower incidence of severe vision impairment with IMRT in comparison to non-IMRT techniques. As observed in the non-IMRT studies, blindness due to disease progression may occur despite a lack of severe toxicity possibly due to the difficulty of controlling locally very advanced disease with a dose ≤ 70 Gy. Concurrent chemotherapy's influence on the the risk of severe optic toxicity after radiotherapy is unclear. A maximum dose of ≤ 54 Gy with conventional fractionation to the optic pathway may decrease the risk of blindness. Increased magnitude of intensity modulation through increasing the number of segments, beams, and using a combination of coplanar and non-coplanar arrangements may help increase dose conformality and optic pathway sparing when IMRT is used.

CONCLUSION

IMRT optimized with appropriate strategies may be the treatment of choice for the most optimal local control and optic pathway sparing when treating sinonasal malignancy.

Cross-talk between leukemic and endothelial cells promotes angiogenesis by VEGF activation of the Notch/Dll4 pathway

Angiogenesis is suggested to be important for leukemogenesis and chemosensitivity in acute myeloid leukemia (AML). The vascular endothelial growth factor (VEGF) and Notch/Dll4 pathways have been identified as critical in the regulation of embryonic vascular development and tumor angiogenesis. However, the potential role of the Notch/Dll4 pathway in leukemia-endothelium cross-talk and its functional link with VEGF remains obscure. This study assessed the expression of VEGF and Notch/Dll4 pathway molecules in primary AML and investigated their biological function in the coculture of endothelial cells with AML cells. The results demonstrated that bone marrow vascularity in the newly diagnosed AML patients was increased and correlated with high VEGF and Dll4 expression. Patients with untreated AML expressed higher levels of VEGFR2, Notch1, Dll4 and Hes1 than healthy controls. Moreover, the activation of the Notch/Dll4 pathway is associated with poor prognosis in AML. In addition, AML cells were shown to increase endothelial cell proliferation in Transwell coculture. This was associated with concomitant activation of the Notch/Dll4 pathway and upregulation of its downstream genes, such as matrix metalloproteinases, resulting in the enhancement of endothelial cell migration and tube formation. Our study also showed that upregulation of Dll4 expression in AML cells by cDNA transfection suppressed VEGF-induced endothelial cell proliferation and angiogenesis in direct contact coculture. These results elucidate a novel mechanism by which the interplay between AML and endothelial cells promotes angiogenesis through the Notch/Dll4 pathway. Modulation of this pathway may, therefore, hold promise as a novel antiangiogenic strategy for the treatment of AML.

Mutation of STAT1/3 binding sites in gp130(FXXQ) knock-in mice does not alter hematopoietic stem cell repopulation or self-renewal potential

Interleukin (IL)-6 family cytokine signaling through gp130 and signal transducer and activator of transcription (STAT) activation is believed important for early hematopoiesis. To determine whether gp130/STAT1/3 physical interaction is required, we compared hematopoietic repopulating activities of embryonic day (E)14.5 fetal liver cells from gp130(FXXQ/FXXQ) knock-in mice, which have four mutated STAT1/3 binding sites. In hematopoietic cells, failure to tyrosine phosphorylate STAT3 by gp130 did not cause any significant effects on myeloid progenitor colony forming units (CFU) in vitro and or on competitive multilineage hematopoietic reconstitution. Serial transplantation of fetal liver (FL) cells was unaffected throughout primary, secondary, and tertiary transplants indicating normal self-renewal capacity. Even gp130(FXXQ/FXXQ) on the background of STAT5 deficiency, with known hematopoietic stem cell (HSC) repopulating dysfunction, did not further impair HSCs beyond that of STAT5 alone. Overall, the defective gp130-mediated STAT1/3 signaling is surprisingly dispensable for HSC function. However, since these mice lack both STAT1/3 binding sites there are several possible explanations for this result and these are discussed.

Th17 related cytokines in acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common hematological malignancy in adults, characterized by distorted proliferation and development of myeloid cells and their precursors in blood and bone marrow. Impressive biologic advances have increased our understanding of leukemogenesis, however, little is known about the pathogenic events which lead to the initiation and progression of AML. T helper type 17 (Th17) cells are a unique subset of CD4+ T cells. They play important roles in the pathogenesis of many diseases, including inflammatory diseases, autoimmune diseases, and cancers. A range of cytokines, such as interleukin (IL)-23, transforming growth factor-beta (TGF-beta), IL-1beta, IL-6, IL-17, IL-22, and IL-21, have been shown related to Th17 cells. Some researchers have reported that the levels of Th17 and its related cytokines were different between normal cells and malignant AML cells, suggesting that Th17 might be involved in AML pathogenesis. In this review, we summarize current progress in the mechanisms of Th17 related cytokines in AML pathogenesis.

Digitoxin and its analogs as novel cancer therapeutics

A growing body of evidence indicates that digitoxin cardiac glycoside is a promising anticancer agent when used at therapeutic concentrations. Digitoxin has a prolonged half-life and a well-established clinical profile. New scientific avenues have shown that manipulating the chemical structure of the saccharide moiety of digitoxin leads to synthetic analogs with increased cytotoxic activity. However, the anticancer mechanism of digitoxin or synthetic analogs is still subject to study while concerns about digitoxin's cardiotoxicity preclude its clinical application in cancer therapeutics. This review focuses on digitoxin and its analogs, and their cytotoxicity against cancer cells. Moreover, a new perspective on the pharmacological aspects of digitoxin and its analogs is provided to emphasize new research directions for developing potent chemotherapeutic drugs.