Biomedical subjects
Publications and source records attributed to Anas Younes.
In recent years, several molecular mechanisms involved in promoting cancer cell survival and growth have been identified. These discoveries helped in designing and testing novel drugs that target specific cellular pathways. In this review, we focus on new molecular targets that are being explored for the treatment of non-Hodgkin's lymphoma and Hodgkin's disease.
c-Kit receptor (CD117) is expressed by erythroid, megakaryocytic, and myeloid precursors and mature mast cells and has been reported to be expressed in CD30+ lymphomas such as Hodgkin's disease and anaplastic large-cell lymphoma. Imatinib mesylate, a well-established inhibitor of bcr-abl tyrosine kinase, and currently used for the treatment of patients with chronic myeloid leukemia, also inhibits c-kit receptor kinase activity. In view of the possible use of imatinib as experimental therapy for patients with c-kit-positive tumors, we assessed c-kit expression in CD30+ cell lines and lymphomas. The cell lines were assessed using multiple methods (RT-PCR, flow cytometry, and Western blot). c-Kit expression was also immunohistochemically assessed in 168 CD30+ lymphomas including 87 classical Hodgkin's disease, 63 anaplastic large-cell lymphoma, and 15 cutaneous anaplastic large-cell lymphoma. We also studied 18 cases of lymphomatoid papulosis, a CD30+ lesion closely related to cutaneous anaplastic large-cell lymphoma. Neither c-kit mRNA nor protein was detected in any of the cell lines assessed. Furthermore, treatment with imatinib did not inhibit proliferation of cell lines in vitro. Using immunohistochemistry, only one of 183 (0.5%) lesions was positive for c-kit, the positive case being an ALK-negative anaplastic large-cell lymphoma. Our data demonstrate that expression of c-kit receptor is exceedingly rare among CD30+ lymphomas and lymphomatoid papulosis, suggesting that c-kit receptor is unlikely to be an appropriate target for therapeutic options such as imatinib in patients with these tumors.
For the past three decades chemotherapy with CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone) has been the standard treatment for aggressive non-Hodgkin's lymphoma (NHL), with only minor changes having been made to the regimen to increase its efficacy. Recently, however, clinical trials have shown significant improvements in outcome in aggressive NHL by showing the benefit of using dose-dense or accelerated schedules as well as by adding rituximab to the standard CHOP regimen. Maintaining the relative dose intensity (that is, delivering the full dose of the chemotherapy on schedule) is an important principle in achieving optimal outcomes in the treatment of NHL. Clinical studies have shown that dose reductions and delays result in poorer outcomes in patients with NHL, and in many cases greater dose intensity appears to result in greater overall and progression-free survival. In particular, compressing the delivery of the standard 21-day CHOP doses into a dose-dense 14-day schedule has been shown to increase event-free survival, overall survival, or both in patients with diffuse large B-cell lymphoma. Consequently, the CHOP-14 regimen (in which the dose intensity is 50% greater than that of the standard regimen) has been adopted by many oncologists for the treatment of aggressive NHL.
Heat shock proteins (HSPs) exist ubiquitously across all species and function as chaperones stabilizing and delivering peptides. Tumor-derived HSP-peptide complex has been known to induce immunity against the original tumor in preclinical studies. HSP-based vaccines work across tumor types and bypass the need for identifying the responsible peptide(s) for inducing immunity. These vaccines are tumor- and patient-specific in that they capture the tumor cells' fingerprints. HSP-based vaccines have been studied in early phase clinical trials, mostly using HSP glycoprotein 96, for various types of malignancies including melanoma, renal cell carcinoma, gastric cancer, pancreatic cancer, low-grade lymphoma, colorectal cancer and chronic myelogenous leukemia. All showed minimal toxicity and potential efficacy. Phase III studies for melanoma and renal cell carcinoma are ongoing. HSP-based vaccines are a novel vaccine preparation with a promising role in cancer management. Further studies to determine the administering strategy and specific indication are warranted.
The peroxisome proliferator-activated receptor gamma (PPAR gamma) is a member of the nuclear receptor family that forms heterodimers with retinoid X receptor. These heterodimers bind to DNA and activate the transcription of target genes. Here, we report that the PPAR gamma receptor protein is expressed in primary myeloid and lymphoid leukemias and in lymphoma and myeloma cell lines. In this study, we compared the activity of several PPAR gamma ligands including BRL49653 (rosiglitazone), 15-deoxy-Delta 12,14-prostaglandin J(2), and the novel triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid on leukemia cells. Exposure to these PPAR gamma ligands induced apoptosis in myeloid (U937 and HL-60) and lymphoid (Su-DHL, Sup-M2, Ramos, Raji, Hodgkin's cell lines, and primary chronic lymphocytic leukemia) cells. A similar exposure to these PPAR gamma ligands induced the differentiation of myeloid leukemic cells. A combination of PPAR gamma ligands with a retinoid X receptor agonist (i.e., LG100268) or a retinoic acid receptor agonist (i.e., all trans-retinoic acid) enhanced differentiating and growth-inhibitory effects. 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic acid induced differentiation and apoptosis with much greater potency than the other PPAR gamma ligands in established cell lines and primary chronic lymphocytic leukemia samples. Exposure to 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid induced mitochondrial depolarization and caspase activation, which was associated with apoptosis induction. In Bcl-2-overexpressing chronic lymphocytic leukemia cells, the small-molecule Bcl-2 inhibitor HA14-1 sensitized these cells to 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid-induced apoptosis. These results suggest that PPAR gamma ligation alone and in combination with retinoids holds promise as novel therapy for leukemias by activating the transcriptional activity of target genes that control apoptosis and differentiation in leukemias.
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PURPOSE: Patients with relapsed mantle-cell lymphoma have poor prognosis and short survival. Our aim was to determine the efficacy of nonablative allogeneic stem-cell transplantation in patients with relapsed mantle-cell lymphoma. PATIENTS AND METHODS: Eighteen patients were treated in one of two consecutive trials. Thirteen patients underwent a conditioning regimen of fludarabine (30 mg/m2 daily for 3 days), cyclophosphamide (750 mg/m2 daily for 3 days), and high-dose rituximab. For the remaining five patients, the conditioning regimen consisted of cisplatin (25 mg/m2 daily for 4 days), fludarabine (30 mg/m2 daily for 2 days), and cytarabine (1,000 mg/m2 daily for 2 days). Tacrolimus and methotrexate were used for graft-versus-host disease prophylaxis. RESULTS: The median age was 56.5 years. Patients underwent a median of three prior chemotherapy regimens. Prior autologous transplantation failed in five (28%) patients and 16 (89%) had chemosensitive disease. Donor cell engraftment occurred in all patients. Eight patients (44%) required no platelet or RBC transfusion, and acute graft-versus-host disease of greater than grade 2 did not develop in any patient. The day-100 mortality was 0%. Complete remission (CR) occurred in 17 patients. Three patients progressed, and one was reinduced into continuous CR with donor lymphocyte infusion. With a median follow-up period of 26 months, the actuarial probability of current-event-free-survival at 3 years was 82% (95% CI, 65% to 99%). CONCLUSION: Our data suggest that nonablative allogeneic transplantation is a safe and potentially effective strategy for patients with relapsed and chemosensitive mantle-cell lymphoma.
Abnormalities of the tumor necrosis factor (TNF) family members have been linked to several human diseases, including cancer. Novel treatment strategies for cancer are emerging based on an understanding of the function of TNF family members. The advantage of these strategies is their potential to selectively target cancer cells, while sparing normal cells. Combining these new strategies with currently available treatments such as chemotherapy and radiation therapy is under investigation, with promising results. However, because some TNF family members are toxic to normal mammalian cells when administered systemically, only a few TNF family members have potential therapeutic value. This concise review focuses on the clinical implications of four TNF family members for cancer treatment: CD30/CD30 ligand, CD40/CD40 ligand, receptor activator of nuclear factor-kappaB (RANK)/RANK ligand, and TNF-related apoptosis-inducing ligand (TRAIL) Apo-2L/TRAIL receptors.
Tumor necrosis factor (TNF), originally identified as a factor produced in the serum of endotoxin-injected animals, is a cytokine that mediates tumor necrosis. To date, 20 different members of the TNF superfamily and 21 different receptors have been identified. All ligands of the TNF superfamily have been found to activate transcription factor NF-kappaB and c-Jun kinase. Members of this family have diverse biologic effects, including induction of apoptosis, promotion of cell survival, and regulation of the immune system. The current review focuses on four members that play important roles in regulating hematopoietic cells and are involved in the pathogenesis of several hematologic malignancies. The potential therapeutic use of these members also is discussed.
BACKGROUND: To explore the potential role of infiltrating benign B cells in classic Hodgkin disease (HD) lesions in supporting the survival of malignant Hodgkin and Reed-Sternberg (H/RS) cells, the authors initiated a pilot study of rituximab. Rituximab is used to primarily deplete normal B cells from HD lesions. METHODS: Patients with recurrent, classic HD who had received a minimum of two prior treatment regimens, regardless of whether H/RS cells expressed CD20, were treated with 6 weekly doses of 375 mg/m2 rituximab to selectively deplete infiltrating benign B cells. Objective tumor response was determined 3 weeks after completion of the last dose of rituximab and every 3 months thereafter. Serum samples were collected from patients before they started rituximab therapy and 3 weeks after the final course of rituximab. Serum cytokine levels of interleukin 6 (IL-6), IL-10, IL-12, IL-13, and interferon gamma were determined using commercially available enzyme-linked immunosorbent assay kits. RESULTS: Twenty-two patients with nodular sclerosis histology were evaluable for treatment response. Five patients (22%) achieved partial or complete remission that lasted for a median of 7.8 months (range, 3.3-14.9 months). Remissions were observed in patients only at lymph node and splenic sites, but not at extranodal sites, and were irrespective of CD20 expression by H/RS cells. Furthermore, systemic (B) symptoms resolved in six of seven patients after therapy. In two patients, partial remissions were associated with a decline in serum IL-6 levels. CONCLUSIONS: The current data suggest that rituximab therapy in patients with recurrent, classic HD can alter serum IL-6 cytokine levels, can improve B symptoms, and may result in clinical remissions.
The mitogen-activated protein kinase (MAPK) (also called extracellular signal-regulated kinase [ERK]) pathway has been implicated in malignant transformation and in the regulation of cellular growth and proliferation of several tumor types, but its expression and function in Hodgkin disease (HD) are unknown. We report here that the active phosphorylated form of MAPK/ERK is aberrantly expressed in cultured and primary HD cells. Inhibition of the upstream MAPK kinase (also called MEK) by the small molecule UO126 inhibited the phosphorylation of ERK and demonstrated a dose- and time-dependent antiproliferative activity in HD cell lines. UO126 modulated the levels of several intracellular proteins including B-cell lymphoma protein 2 (Bcl-2), myeloid cell leukemia-1 (Mcl-1) and caspase 8 homolog FLICE-inhibitory protein (cFLIP), and induced G2M cell-cycle arrest or apoptosis. Furthermore, UO126 potentiated the activity of apoliprotein 2/tumor necrosis factor-related apoptosis-inducing ligand (APO2L/TRAIL) and chemotherapy-induced cell death. Activation of CD30, CD40, and receptor activator of nuclear kappabeta (RANK) receptors in HD cells by their respective ligands increased ERK phosphorylation above the basal level and promoted HD cell survival. UO126 inhibited basal and ligand-induced ERK phosphorylation, and inhibited ligand-induced cell survival of HD cell lines. These findings provide a proof-of-principle that inhibition of the MEK/ERK pathway may have therapeutic value in HD.
BACKGROUND: The reported frequency of gastrointestinal (GI) tract involvement in patients with mantle cell lymphoma (MCL) is 15-30%. However, this figure most likely is an underestimate because most patients with MCL involving the GI tract previously reported were examined endoscopically only if they had GI tract symptoms. The impact of endoscopic assessment on the management of MCL patients is unknown. METHODS: From March 1998 to May 2001 baseline upper and lower endoscopy of the GI tract was performed in consecutive untreated patients with MCL as part of a prospective therapeutic trial. Biopsies were performed on abnormal as well as macroscopically normal mucosa. Endoscopy was repeated during treatment and as part of follow-up evaluations. RESULTS: Only 26% of patients presented with GI symptoms at the time of diagnosis. MCL was present histologically in the lower GI tract of 53 of 60 patient (88%) and in the upper GI tract of 28 of 58 patients (43%). Microscopic evidence of MCL was found in 84% of patients with normal visual (macroscopic) findings by lower endoscopy and in 45% of patients with macroscopically normal findings by upper endoscopy. Despite this high frequency of GI tract involvement, the use of upper and lower endoscopy with biopsies in this group of patients resulted in changes in clinical management in only three (4%) patients. CONCLUSIONS: Gastrointestinal tract involvement was found to be present in most patients with MCL, usually at a microscopic level involving macroscopically normal mucosa. The use of aggressive staging evaluation of the GI tract was found to have little impact on patient management decisions in the current study.
PURPOSE: We analyzed in-field (IF) control in adults with early-stage Hodgkin's disease who received chemotherapy followed by radiotherapy (RT) in terms of the (1) chemotherapeutic regimen used and number of cycles delivered, (2) response to chemotherapy, and (3) initial tumor size. Cardiac toxicity and second malignancies, particularly the incidence of solid tumors in terms of the RT field size treated, were also examined. METHODS AND MATERIALS: From 1980 to 1995, 286 patients ranging in age from 16 to 88 years (median: 28 years) with Ann Arbor clinical Stage I or II Hodgkin's disease underwent chemotherapy followed 3 to 4 weeks later by RT. There were 516 nodal sites measuring 0.5 to 19.0 cm at the start of chemotherapy, including 134 cases of bulky mediastinal disease. NOVP, MOPP, ABVD, CVPP/ABDIC, and other chemotherapeutic regimens were given to 161, 67, 19, 18, and 21 patients, respectively. Patients received 1-8 (median: 3) cycles of induction chemotherapy. All 533 gross nodal and extranodal sites of disease were included in the RT fields. The median prescribed RT dose for gross disease was 40.0 Gy given in 20 daily 2.0-Gy fractions. There was little variation in the RT dose. Eighty-five patients were treated with involved-field or regional RT (to one side of the diaphragm), and 201 patients were treated with extended-field RT (to both sides of the diaphragm), based on the protocol on which they were enrolled. RESULTS: Follow-up of surviving patients ranged from 1.3 to 19.9 years (median: 7.4 years). Based on a review of simulation films, there were 16 IF, 8 marginal, and 15 out-of-field recurrences. The chemotherapeutic regimen used and the number of cycles of chemotherapy delivered did not significantly affect IF control. IF control also did not significantly depend on the response to induction chemotherapy. In cases where there was a confirmed or unconfirmed complete response as opposed to a partial response or stable disease in response to induction chemotherapy for bulky nodal disease, the 5-year IF control rates were 99% and 92%, respectively (p = 0.0006). The 15-year actuarial risks of coronary artery disease requiring surgical intervention and of solid tumors were 4.1% and 16.8%, respectively. There was a trend toward a greater risk of solid tumors in patients who received extended-field RT rather than involved-field or regional RT (p = 0.08). CONCLUSIONS: In patients with nonbulky disease, induction chemotherapy followed by RT to a median dose of 40.0 Gy resulted in excellent IF control, regardless of the chemotherapeutic regimen used, the fact that only 1-2 cycles of chemotherapy were delivered, and the response to chemotherapy. There was a trend toward a higher incidence of solid tumors in patients who received consolidation RT to both sides rather than only one side of the diaphragm. Ongoing Phase III trials will help clarify whether lower RT doses and smaller RT fields after chemotherapy can maintain the IF control seen in our study, but with a lower incidence of late complications in patients with Stage I or II Hodgkin's disease.
The factors regulating the growth of follicular dendritic cell (FDC) sarcoma are currently unknown. Using cDNA microarray analysis, we found that the epidermal growth factor receptor (EGFR) is expressed in FDC sarcoma. We immunohistochemically examined the expression of EGFR in a larger series of FDC sarcomas and in nonneoplastic FDCs. This included 8 cases of FDC sarcoma, 12 cases of hyaline vascular Castleman's disease (CD), 5 cases of human herpesvirus 8 (HHV8)-positive plasma cell CD, 7 cases of HHV8-negative plasma cell CD, 13 cases of reactive lymph nodes, 3 cases of reactive tonsils, 10 cases of follicular lymphoma, 6 cases of nodular mantle cell lymphoma, and 6 cases of angioimmunoblastic T-cell lymphoma. EGFR was expressed in tumor cells in 7 of 8 cases (88%) of FDC sarcoma (strongly in 4 cases and moderately in 3 cases). The single EGFR-negative case had an anaplastic appearance and a more aggressive clinical behavior. EGFR was also expressed by FDC in all types of CD (strongly in 4 cases, moderately in 16 cases, and weakly in 4 cases). Immunostaining results were negative or only weakly positive for EGFR in FDC of reactive lymph nodes and tonsils, and in the FDC networks of follicular lymphoma, mantle cell lymphoma, and angioimmunoblastic lymphoma. The up-regulation of EGFR in FDC of CD was paralleled by an increase in EGFR expression in the surrounding perifollicular fibroblastic reticulum cells suggesting coordinate regulation. These findings identify a differentially expressed growth regulatory receptor common to both FDC sarcoma and CD, identifying a target for possible therapy in unresectable or refractory cases.
Nuclear factor-kappaB (NF-kappaB) is a transcriptional factor that was originally discovered in the nucleus of B cells that bind to the kappa light chain of the immunoglobulins. Research during 15 years, however, has revealed that NF-kappaB is present in its inactive state in the cytoplasm of almost every cell type. When activated, NF-kappaB translocates to the nucleus, binds the DNA and regulates the expression of over 200 different genes. The product of these genes regulate the immune system, cell proliferation, tumor metastasis, inflammation and viral replication. Several tumor cell types express constitutively activated form of NF-kappaB and it is required for the proliferation of the tumor cells. Numerous studies have shown that Hodgkin's disease cells exhibit constitutive active NF-kappaB. The present review examines the mechanism how NF-kappaB is activated and its relevance to Hodgkin's disease.
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Treatment for patients with stage IV indolent lymphoma ranges from watchful waiting to intensive chemotherapy and stem cell transplantation. In this trial we compared 2 induction regimens followed by 1 year of interferon maintenance therapy. Fludarabine, mitoxantrone (Novantrone), and dexamethasone (FND) were compared with an alternating triple therapy (ATT) regimen (CHOD-Bleo, ESHAP, and NOPP). Maintenance interferon/dexamethasone was given for 1 year in both treatment arms. Endpoints were comparisons of remission rates, survival, failure-free survival (FFS), molecular response rates, and toxicities. One hundred forty-two patients with previously untreated stage IV indolent lymphoma were evaluable (73 on FND; 69 on ATT). The overall response rates were 97% for FND and 97% for ATT (P =.9). The median follow-up is 5.9 years. The 5-year survival rates were 84% with FND and 82% with ATT (P =.9); the 5-year FFS rates were 41% with FND and 50% with ATT (P =.02). In a multivariate analysis, factors predicting for longer FFS were beta(2)-microglobulin less than 3 mg/L (P =.01) and ATT treatment (P =.03). ATT was associated with a substantially higher rate of grade 3-4 toxicities than FND. In conclusion, both regimens were associated with high rates of response and survival. ATT was associated with substantially longer FFS, but it was more toxic than FND.