Effect of all trans-retinoic acid (ATRA) on the adhesive and motility properties of acute promyelocytic leukemia cells

Differentiation Syndrome in Acute Leukemia: APL and Beyond

Differentiation syndrome (DS) is a frequent and potentially life-threatening clinical syndrome first recognized with the advent of targeted therapeutics for acute promyelocytic leukemia (APL). DS was subsequently observed more broadly with targeted therapeutics for acute myeloid leukemia (AML). DS is typically characterized by fever, dyspnea, hypotension, weight gain, pleural or pericardial effusions, and acute renal failure. The incidence in patients with APL ranges from 2 to 37%, with the wide variation likely attributed to different diagnostic criteria, use of prophylactic treatment, and different treatment regimens. Treatment with corticosteroids +/- cytoreductive therapy should commence as soon as DS is suspected to reduce DS-related morbidity and mortality. The targeted anti-leukemic therapy should be discontinued in patients with severe DS. Here, we discuss the pathogenesis of DS, clinical presentations, diagnostic criteria, management strategies, and implementation of prospective tracking on clinical trials.

Distinct Characteristics of Sweet's Syndrome of the Scrotum Caused by All-trans Retinoic Acid in a Patient with Acute Promyelocytic Leukemia

Induction therapy with all-trans retinoic acid (ATRA) is effective for acute promyelocytic leukemia (APL). ATRA induces neutrophil differentiation and its associated side effects. The differentiation syndrome is the most characterized ATRA-induced adverse effect. Sweet's syndrome, also known as neutrophilic dermatosis, is another form of ATRA-associated disease characterized by neutrophil infiltrating erythema that develops with fever. This is a case of a 34-year-old Japanese man diagnosed with APL. At the onset, the patient did not have skin involvement of APL cells. He was treated with ATRA and induction chemotherapy with idarubicin and cytarabine. Scrotal skin rash occurred at day 14, which developed into scrotal ulceration up to day 28 even after eliminating APL cells in his peripheral blood. Sweet's syndrome is a pathological diagnosis of scrotal skin ulceration representing neutrophil infiltration. The infiltrating neutrophils showed PML-RARα rearrangement. The patient was diagnosed with ATRA-associated Sweet's syndrome with skin ulcer. His cutaneous lesion did not respond to intravenous prednisolone therapy; thereby, ATRA was discontinued. After the cessation of ATRA, the skin lesion improved in the next week. We confirmed he achieved a complete response after induction chemotherapy. In our observation, ATRA-associated Sweet's syndrome is characterized by the following clinical manifestations: preferable occurrence in the scrota, tend to progress into skin ulcer, and pathogenicity associated with PML-RARα-positive matured neutrophils. The etiology, pathogenesis, and risk factors of ATRA-associated scrotal ulceration were discussed in the literature review.

All-Trans Retinoic Acid Enhances Matrix Metalloproteinase 2 Expression and Secretion in Human Myeloid Leukemia THP-1 Cells

All-trans retinoic acid (ATRA) is an effective drug for the induction therapy of acute promyelocytic leukemia. However, the treatment is associated with adverse events such as retinoic acid syndrome (RAS) in some patients, whose histologic characteristics included organ infiltration by leukemic cells. Matrix metalloproteinase 2 (MMP-2) is often upregulated in tumor cells and plays a role in tumor cell migration and invasion by degrading the extracellular matrix. In this study, we examined the possible modulatory effects of ATRA on MMP-2 expression and secretion in human myeloid leukemia cell line THP-1. The cells were treated with various concentrations of ATRA, and MMP-2 expression and secretion were examined. MMP-2 expression and secretion started to increase with ATRA concentration as low as 0.1 nM and gradually increased thereafter. Agonists of retinoic acid receptor (RAR) or retinoid X receptor (RXR) alone could enhance MMP-2 secretion, and RAR or RXR antagonists alone could reverse ATRA-induced MMP-2 secretion. ATRA increased intracellular calcium ion levels, and a calcium-channel blocker inhibited ATRA-induced MMP-2 secretion. Dexamethasone suppressed ATRA-induced MMP-2 secretion. Our results suggest that ATRA enhances MMP-2 expression and secretion in human myeloid leukemia THP-1 cells in a calcium ion dependent manner through RAR/RXR signaling pathways, and this enhanced expression and secretion may be associated with the possible mechanisms of RAS.

Phagocytosis of Terminally Differentiated Acute Promyelocytic Leukemia Cells by Marrow Histiocytes During Treatment with All-transRetinoic Acid

It has been established that acute promyelocytic leukemia (APL) cells are induced to terminally differentiate by all-trans retinoic acid (ATRA), however, the clearance of differentiated APL cells in vivo has not been well understood. Here, we documented the elimination of terminally differentiated APL cells by histiocytes in bone marrow during differentiation induction therapy. In two ATRA-treated APL patients, bone marrow showed the striking phagocytosis of differentiated APL cells by histiocytes just before the achievement of complete remission. Histiocytes phagocytosed APL cells at the terminal stage of differentiation prior to the late apoptotic event of cell lysis. Engulfed APL cells then undergo morphological features of late apoptosis and finally fragmentation in the cytoplasm of histiocytes. This swift and efficient elimination of APL cells undergoing apoptosis by the histiocytes in bone marrow may be possible pathway, at least partially, for the clearance of differentiated APL cells.

Advances in understanding the pulmonary infiltration in acute promyelocytic leukaemia

In acute promyelocytic leukaemia (APL), differentiation therapy can be complicated by the development of a differentiation syndrome (DS). Pulmonary infiltration of differentiating leukaemic cells is a key event in the development of DS. Several mediators have been identified that may promote migration and extravasation of differentiating APL cells from the bloodstream into the tissue. Adhesion of APL cells to each other and to the endothelium is induced by upregulation of the expression of adhesion molecules and constitutively active β2-integrins during differentiation therapy. The expression of chemokines and their receptors is significantly upregulated as well. Pulmonary chemokine production can trigger transendothelial migration of differentiating APL cells from the bloodstream into the underlying tissue (initiation phase of DS). Massive production of chemokines by infiltrated APL cells can further enhance transendothelial migration of differentiating APL cells, causing an uncontrollable hyperinflammatory reaction in the lung (aggravation phase), which is not efficiently switched-off by corticosteroids.

Chemokine induction by all-trans retinoic acid and arsenic trioxide in acute promyelocytic leukemia: triggering the differentiation syndrome

In acute promyelocytic leukemia (APL), differentiation therapy with all-trans retinoic acid (ATRA) and/or arsenic trioxide can induce a differentiation syndrome (DS) with massive pulmonary infiltration of differentiating leukemic cells. Because chemokines are implicated in migration and extravasation of leukemic cells, chemokines might play a role in DS. ATRA stimulation of the APL cell line NB4 induced expression of multiple CC-chemokines (CCLs) and their receptors (> 19-fold), resulting in increased chemokine levels and chemotaxis. Induction of CCL2 and CCL24 was directly mediated by ligand-activated retinoic acid receptors. In primary leukemia cells derived from APL patients at diagnosis, ATRA induced chemokine production as well. Furthermore, in plasma of an APL patient with DS, we observed chemokine induction, suggesting that chemokines might be important in DS. Dexamethasone, which efficiently reduces pulmonary chemokine production, did not inhibit chemokine induction in APL cells. Finally, chemokine production was also induced by arsenic trioxide as single agent or in combination with ATRA. We propose that differentiation therapy may induce chemokine production in the lung and in APL cells, which both trigger migration of leukemic cells. Because dexamethasone does not efficiently reduce leukemic chemokine production, pulmonary infiltration of leukemic cells may induce an uncontrollable hyperinflammatory reaction in the lung.

Studies on Multifunctional Effect of All-Trans Retinoic Acid (ATRA) on Matrix Metalloproteinase-2 (MMP-2) and Its Regulatory Molecules in Human Breast Cancer Cells (MCF-7)

Background. Vitamin A derivative all-trans retinoic acid (ATRA) is considered as a potent chemotherapeutic drug for its capability of regulating cell growth and differentiation. We studied the effect of ATRA on MMP-2 in MCF-7, human breast cancer cells, and the probable signaling pathways which are affected by ATRA on regulating pro-MMP-2 activity and expression. Methods. Gelatin zymography, RT-PCR, ELISA, Western blot, Immunoprecipitation, and Cell adhesion assay are used. Results. Gelatin zymography showed that ATRA caused a dose-dependent inhibition of pro-MMP-2 activity. ATRA treatment downregulates the expression of MT1-MMP, EMMPRIN, FAK, NF-kB, and p-ERK. However, expression of E-cadherin, RAR, and CRABP increased upon ATRA treatment. Binding of cells to extra cellular matrix (ECM) protein fibronectin reduced significantly after ATRA treatment. Conclusions. The experimental findings clearly showed the inhibition of MMP-2 activity upon ATRA treatment. This inhibitory effect of ATRA on MMP-2 activity in human breast cancer cells (MCF-7) may result due to its inhibitory effect on MT1-MMP, EMMPRIN, and upregulation of TIMP-2. This study is focused on the effect of ATRA on MMP, MMP-integrin-E-cadherin interrelationship, and also the effect of the drug on different signaling molecules which may involve in the progression of malignant tumor development.

Retinoic acid in the immune system

On occasion, emerging scientific fields intersect and great discoveries result. In the last decade, the discovery of regulatory T cells (T(reg)) in immunity has revolutionized our understanding of how the immune system is controlled. Intersecting the rapidly emerging field of T(reg) function, has been the discovery that retinoic acid (RA) controls both the homing and differentiation of T(reg). Instantly, the wealth and breadth of knowledge of the molecular basis for RA action, its receptors, and how it controls cellular differentiation can and will be exploited to understand its profound effects on T(reg). Historically, vitamin A deprivation and repletion and RA agonists have been shown to profoundly affect immunity. Now these findings can be interpreted in light of the revelations that RA controls leukocyte homing and T(reg) function.

All-transRetinoic Acid Enhances Murine Dendritic Cell Migration to Draining Lymph Nodes via the Balance of Matrix Metalloproteinases and Their Inhibitors

Cancers escape immune surveillance through the manipulation of the host's immune system. Sequestration of dendritic cells (DCs) within tumor tissues and the subsequent inhibition of their migration is one of the several mechanisms by which tumors induce immunosuppression. In view of recent findings depicting the improvement of tumor immune responses in cancer patients following all-trans retinoic acid (ATRA) treatment, we sought to identify the effects of ATRA on DC mobility in the context of tumor immunotherapy. Our results demonstrate that ATRA, added to differentiating murine bone marrow progenitor cells, enhances the invasive capacity of the resulting DCs. Immature DCs injected intratumorally in mice show increased accumulation in draining lymph nodes, but not in nondraining lymph nodes and spleens, when differentiated in the presence of ATRA. The in vitro migration of mature DCs through the basement membrane matrix toward the lymphoid chemokines CCL19 and CCL21 is enhanced in these cells, albeit not in the presence of a matrix metalloproteinase (MMP) inhibitor. An increase in MMP production with a simultaneous decrease in the production of their inhibitors (tissue inhibitors of matrix metalloproteinase or TIMPs) is provoked by ATRA. This affects the MMP/TIMP balance in DCs, in particular that of MMP-9 and TIMP-1, favoring protease activity and thus allowing for enhanced DC mobilization. In conclusion, this study demonstrates that ATRA is capable of improving DC trafficking in a tumor milieu and, in view of the encouraging results obtained in the clinic, further supports the notion that ATRA might be a valuable chemical adjuvant to current immunotherapeutic strategies for cancer.

Catalase potentiates retinoic acid-induced THP-1 monocyte differentiation into macrophage through inhibition of peroxisome proliferator-activated receptor gamma

Macrophage differentiation plays a pivotal role in cardiovascular diseases and many other physiological processes. However, the role of reaction oxygen species in macrophage differentiation has not been elucidated. Here, we report functional characterization of catalase, an enzyme that degrades hydrogen peroxide (H(2)O(2)), in THP-1 monocyte differentiation. Treatment of THP-1 cells with catalase was able to synergize with all-trans retinoic acid (ATRA) to enhance macrophage differentiation, demonstrated by changes of cell adherence, cell cycle arrest, nitroblue tetrazolium reduction, and expression of differentiation markers including CD68, CD11b, and matrix metalloproteinase 9 (MMP9). ATRA could stimulate retinoic acid (RA) receptor-mediated transcription, but this was not affected by catalase. However, ATRA and catalase were capable of reducing transcriptional activity mediated by peroxisome proliferator-activated receptor gamma (PPARgamma). Consistently, PPARgamma antagonists enhanced, and PPARgamma agonists inhibited MMP9 expression stimulated by ATRA and catalase in THP-1 cells. Therefore, these data indicate that catalase is able to potentiate ATRA-induced macrophage differentiation by inhibition of PPARgamma activity, underscoring an important interplay between H(2)O(2), RA, and PPARgamma in macrophages.

Retinoic acid-induced CD38 antigen promotes leukemia cells attachment and interferon-gamma/interleukin-1beta-dependent apoptosis of endothelial cells: implications in the etiology of retinoic acid syndrome

All-trans retinoic acid (RA) treatment of patients with acute promyelocytic leukemia (APL) induces complete remission in more than 90% of the cases. Although RA therapy is well tolerated, about 25% of APL patients develop a potentially fatal condition called retinoic acid syndrome (RAS). Molecular mechanisms underlying the development of RAS pathogenesis, especially those that result in the damage of endothelial cells remain elusive. In the present study, we found that RA treatment induces the expression of interferon-gamma (IFN-gamma) and interleukin-1beta (IL-1beta) in peripheral blast cells from APL patients. IFN-gamma and IL-1beta also exerted synergistic effect in driving human umbilical cord endothelial cells (HUVECs) and human lung microvascular endothelial cells (HLMVECs) into apoptosis. RA also upregulated the expression of CD38, an ectoenzyme responsible for the generation of the calcium messenger cyclic ADP-ribose. Importantly, RA-induced CD38 expression promoted strong attachment of leukemia cells to endothelial cells, and incubation of endothelial cells with either high concentration (100 ng/ml) of IFN-gamma alone or low concentration of IL-1beta and IFN-gamma (10 ng/ml, each) induced strong apoptotic responses as revealed by caspase-8 activation and DNA fragmentation. Our results suggest that these RA-induced events could contribute to the development of RAS pathogenesis in patients with APL.

Mofarotene-induced inhibition of melanoma cell motility by increasing vinculin-containing focal contacts

Tumour cell motility, which is dependent on the organization of the cytoskeleton, is considered to play an important role in the spread of malignant melanoma. Therefore, retinoids, which are modulators of cytoskeletal organization, may affect the motile activity of melanoma cells. In this study, the effects of the arotinoid mofarotene on single cell motility and vinculin organization of the highly metastatic melanoma cell line K-1735-M2 were determined. Melanoma cells were cultivated in a temperature- and CO2-controlled microincubator, which was located on the microscope stage. Cell movements were evaluated quantitatively from time-lapse video recordings using an IBAS image analysis system. Vinculin distribution was evaluated using confocal laser scanning microscopy and a specially developed computerized image analysing program. In addition, melanoma cell invasion was tested on the embryonic chick heart model. Although 10 microM mofarotene did not reduce the translocative movements of melanoma cells, it significantly inhibited stationary motility, including fast plasma membrane movements and changes in shape. Mofarotene also showed a pronounced effect on the organization of vinculin-containing cell-substratum adhesion plaques. In retinoid-treated cells, the numbers of vinculin plaques per cell, and particularly those in the marginal areas of the cells, were significantly increased compared with untreated controls. Furthermore, the compound reduced the invasiveness of melanoma cells in a three-dimensional tissue culture model. In conclusion, our data demonstrate that mofarotene, an already almost forgotten synthetic retinoid, shows interesting effects on melanoma cells, which may be relevant for a slowdown of tumour spread.

Retinoic acid syndrome in NOD/scid mice induced by injecting an acute promyelocytic leukemia cell line

All-trans retinoic acid (ATRA) induces complete remission in patients with acute promyelocytic leukemia (APL). However, ATRA sometimes causes retinoic acid syndrome (RAS) characterized by respiratory distress, pleural effusions, fever and weight gain. To investigate the pathophysiology of RAS, we generated an animal model by injecting an APL cell line, NB4, into immunodeficient mice. When NOD/scid mice were injected intravenously with fully differentiated NB4 cells (1 x 10(7)) and then given a daily administration of ATRA, three of 12 mice died of pulmonary edema within 14 days. Pathologically, dilated lung capillary vessels and alveolar effusions were observed. After the injection, NB4 cells were detected in the lung within 2 days and in the pleural effusion later on. The gene expression levels of CXC chemokines (MIP-2 and KC) and ICAM-1 were increased in the lung and heart by the ATRA administration. In immunohistochemical analyses, MIP-2 was clearly detected in alveolar macrophages of the lung in mice with RAS. Dexamethasone treatment prevented the development of RAS and decreased the CXC chemokine mRNA expression in the lung. These findings suggested that the activation of adhesion molecules for leukocytes and expression of CXC chemokines in the lung are closely involved in triggering RAS.

Intercellular adhesion molecule-1 in extravasation of normal mononuclear and leukaemia cells

Interaction of intercellular adhesion molecules (ICAMs) with their receptors has a key role in normal leucocyte adhesion and migration, whereas in leukaemia this has not been well established. In this study, we have evaluated the roles of different adhesion molecules in normal and leukaemia cell extravasation in a novel organotypic model for vessel wall and measured plasma ICAM-1 and -2 levels in acute leukaemia patients at diagnosis and during chemotherapy. We found that both normal mononuclear cells and blast cells from acute leukaemia patients, as well as retinoic acid-treated promyelocytic leukaemia cells, rapidly extravasated through endothelial cell layers into the underlying collagen matrix. ICAM-1 antibody prevented the extravasation, while antibodies to other adhesion molecules showed little (CD18, ICAM-2) or no inhibition (CD11a and ICAM-3). Soluble ICAM-1 (sICAM-1) protein had no effect. We also observed increased plasma sICAM-1 and -2 levels in leukaemia patients and found that they correlated only weakly with the white blood cell count. No correlation was found between sICAM-1 or -2 levels and the response to therapy. Although elevated sICAM-2 levels decreased rapidly during chemotherapy, sICAM-1 levels did not. Because sICAM-1 protein had no effect on leukaemia cell extravasation in vitro, it is probable that the increased plasma sICAM-1 levels in leukaemia patients may not play a role in leukaemia cell infiltration. However, as we showed that ICAM-1 mediated leukaemia cell extravasation on the cell surface, it is possible that cellular ICAM-1 has an important role in disease progression.

Leukocytosis and the retinoic acid syndrome in patients with acute promyelocytic leukemia treated with arsenic trioxide

PURPOSE

Arsenic trioxide, like all-trans-retinoic acid (RA), induces differentiation of acute promyelocytic leukemia (APL) cells in vivo. Treatment of APL patients with all-trans RA is commonly associated with leukocytosis, and approximately 50% of patients develop the RA syndrome. We reviewed our clinical experience with arsenic trioxide to determine the incidence of these two phenomena.

PATIENTS AND METHODS

Twenty-six patients with relapsed or refractory APL were treated with arsenic trioxide for remission induction at daily doses that ranged from 0.06 to 0.17 mg/kg.

RESULTS

Twenty-three patients (88%) achieved complete remission. Leukocytosis was observed in 15 patients (58%). The median baseline leukocyte count for patients with leukocytosis was 3,900 cells/microL (range, 1,200 to 72,300 cells/microL), which was higher than that for patients who did not develop leukocytosis (2,100 cells/microL; range, 500 to 5,400 cells/microL; P =.01). No other cytotoxic therapy was administered, and the leukocytosis resolved in all cases. The RA syndrome was observed in eight patients (31%). Patients who developed leukocytosis were significantly more likely to develop the RA syndrome (P <.001), and no patient without a peak leukocyte count greater than 10,000 cells/microL developed the syndrome. Among the patients with leukocytosis, there was no observed relation between the leukocyte peak and the probability of developing the syndrome (P =.37).

CONCLUSION

Induction therapy of APL with all-trans RA and arsenic trioxide is associated with leukocytosis and the RA syndrome. These clinical effects seem to be intrinsically related to the biologic responsiveness and the differentiation process induced by these new agents.

Antiproliferative activity of interferon alpha and retinoic acid in SiHa carcinoma cells: the role of cell adhesion

Several lines of evidence have demonstrated that IFNs could be relevant in the treatment of certain neoplastic diseases such as carcinomas. In particular, IFN-alpha, in addition to the anti-proliferative and cytostatic effects, was demonstrated to be capable of inducing cell death by apoptosis both in vivo and in vitro. Numerous protocols have also been proposed which consider the association of IFN-alpha with other drugs. Among these are retinoids, a class of compounds capable of inducing inhibition of cell growth and differentiation. We address the question here by analyzing the role of cell adhesion in susceptibility to IFN-alpha, RA and their combination of a human cell line derived from a squamous carcinoma of the cervix, the Bcl-2-negative SiHa cell line. In this context, cytoskeleton components and several surface molecules playing a role in cell substrate and cell-to-cell relationships have been evaluated. We found that RA treatment is capable of improving stress fiber formation, decreasing cell detachment and increasing cell-adhesion capability. However, no variations in the ability to adhere to specific extracellular-matrix molecules were found in RA-treated cells. No quantitative changes were detected in integrins involved as receptors for extracellular matrix molecules (VLAI-VLA5) or in other cell-adhesion-associated molecules (e.g., CD44). By contrast, 2 important molecules involved in cell-adhesion processes appeared to be up-regulated by RA exposure: focal adhesion kinase and E-cadherin, involved in adhesion plaque formation and cell-to-cell contacts, respectively. Keeping in mind the importance of adhesion properties in the cell-growth pathway, our findings could be of interest in the study of carcinoma-cell proliferation and metastatic potential.