Abstract 6129: The proapoptotic peptide PEP-010 is efficient on several models of different tumor origins and it can be monitored by pharmacodynamic biomarker candidates in clinical practice

In cancer cells, the proapoptotic proteins caspase-9 and PP2A interaction prevents them to play their role in apoptosis. PEP-010, a drug candidate developed by PEP-Therapy, a French Biotech company, is a proapoptotic peptide targeting and disrupting this interaction leading to restoration of the apoptotic cascade. PEP-010 is an innovative bifunctional peptide. It penetrates into cells thanks to its cell penetrating part and specifically disrupts the caspase-9/PP2A interaction thanks to its interfering part. PEP-010 is currently in Phase I a/b multicenter clinical trial for the treatment of advanced solid tumors.To the aim of screening different potential therapeutic targets, to investigate the molecular mechanism-of-action of PEP-010 and to identify potential pharmacodynamic biomarkers, we have tested PEP-010 efficacy on several cell models of different tumor origins. By the Annexin V/Propidium Iodide staining and flow cytometry analysis, we found that PEP-010 induces apoptosis in most of the tested models. One possible mechanism-of-action is an involvement of the PP2A which, once released by PEP-010, could regulate expression and/or activity of different intracellular factors leading to caspases activation and cell death.The identification of the major molecular features involved in PEP-010 mechanism-of-action, were instrumental to identify different pharmacodynamic biomarker candidates (e.g. active caspase-3). Hence, such biomarkers could be useful in clinical practice to monitor the effect of PEP-010 at molecular level. We have compared specific features related to the mechanism-of-action of PEP-010 in sensitive (MDA-MB-231, IGROV1) and not sensitive cell models of different tumor origins and in tissue sections derived from Patient-Derived Xenografts models of breast cancer treated or not with PEP-010. Widely used techniques as immunofluorescent staining and immunohistochemistry were employed, making these results easily transferable in clinical routine.Taken together, our pre-clinical data showed the potential of PEP-010 as an anti-cancer peptide on a wide variety of malignancies and enabled the identification of pharmacodynamic biomarker candidates, important to ease the clinical development.

Citation Format: Rayan Farhat, Laura Dadon, F Nemati, A Rebollo, D Decaudin, Joelle Wiels, Catherine Brenner, Diego Germini. The proapoptotic peptide PEP-010 is efficient on several models of different tumor origins and it can be monitored by pharmacodynamic biomarker candidates in clinical practice. [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 6129.

Abstract P6-04-14: Targeting the PI3K/mTOR pathway in patient-derived xenograft models of endocrine resistant luminal breast cancer

Background. Most ER+ tumors will eventually escape endocrine treatments. PI3K/mTOR pathway targeting has improved clinical results in endocrine treatments resistant (ETR) patients, however with unsustained responses. Our laboratory has developed several models of ETR luminal breast cancer (LBC) patient derived xenografts (PDX) suitable for biological studies (Cottu et al, AACR 2012 & IMPAKT 2012). The aims of the present study were 1) to analyze the biological factors associated with acquired ETR in relevant models of LBC; 2) to determine the therapeutic interest of combining everolimus with different ET models resistant to different endocrine treatments (ET).

Methods. Implementation of LBC models has been reported (Cottu et al, BCRT 2012). ETR models were derived by selecting tumors growing under continuous ET, subsequently re-engrafted and rechallenged with endocrine therapies (tamoxifen, letrozole, fulvestrant), and with everolimus alone and combined with ETs. When possible, initial sensitive tumors were simultaneously treated with the same protocols. At progression, or after at least 120 days of continuous therapies, tumor tissue was retrieved. Tissue microarrays (TMA) were performed to analyze the biological modifications associated to ET and mTOR targeting. Triplicate immunohistochemistry of P-AKT/AKT, P-mTOR/mTOR and P-S6 were performed in addition to standard markers. Transcriptomic and RTPCR analyses are also being conducted.

Results. Three models resistant to tamoxifen and 2 models resistant to surgical ovariectomy used a surrogate to estrogen deprivation, were developed from 3 initial PDX, and were maintained as independent hormone-resistant variants. All these models retained a luminal phenotype, based on IHC and transcriptomic analyses and had a wt PI3KCA. ETR models had an expression profile very similar to the initial PDX, suggesting that minor changes may be associated with the acquisition of an ETR phenotype. Three of these models have been tested. One tamoxifen resistant model confirmed a resistance specific to tamoxifen only and a high level of sensitivity to a fulvestrant everolimus combination. A second PDX yielded 2 other models resistant to tamoxifen and ovariectomy. These 2 models developed a resistance to all ET modalities. Therapeutic testing with combinations of everolimus and ETs were highly efficient, but everolimus alone was as efficient in these 2 models with complete and durable responses. Activation of the PI3K pathway was demonstrated in all cases by IHC analyses (expression of pAKT and pS6), and complementary ongoing RTPCR analyses. Everolimus based effects were associated with tumor fibrosis, a strong inhibition of Ki67 and pS6, but not always pAKT. The expression of ER was not modified by treatments, except in the fulvestrant-treated mice where it was strongly inhibited.

Conclusion. We have developed and validated a platform of ETR models derived from our LBC original PDX. These models retained a luminal phenotype although highly resistant to ET. Activation of the PI3K pathway has been confirmed in ETR models, and everolimus alone, or combined with ET confirms high and durable efficacy. Updated mechanistic analyses performed at different time points will be presented at the meeting.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-14.

[Breast conserving surgery in locoregional treatment of breast carcinoma after Hodgkin lymphoma]

PURPOSE

To report characteristics and outcome of breast cancer after irradiation for Hodgkin lymphoma with special focus on breast conservation surgery.

PATIENTS AND METHODS

Medical records of 72 women who developed either ductal carcinoma in situ or stage I-III invasive carcinoma of the breast after Hodgkin lymphoma between 1978 and 2009 were retrospectively reviewed.

RESULTS

Median age at Hodgkin lymphoma diagnosis was 23 years old. Median total dose received by the mediastinum was 40 Gy, mostly by a mantle field technique. Breast cancer occurred after a median time interval of 21 years. Ductal invasive carcinoma and ductal carcinoma in situ represented respectively 71% and 19% of the cases. Locoregional treatment for breast cancer consisted of mastectomy with or without radiotherapy in 39 patients and of lumpectomy with or without adjuvant radiotherapy in 32 patients. The isocentric lateral decubitus radiation technique was used in 17 patients after breast conserving surgery (57%). With a median follow-up of 7 years, 5-year overall survival rate and locoregional control rate were respectively 74.5% and 82% for invasive carcinoma and 100% and 92% for in situ carcinoma. Thirteen patients died of progressive breast cancer and contralateral breast cancer was diagnosed in ten patients (14%).

CONCLUSIONS

Breast conserving treatment can be an option for breast cancers that occur after Hodgkin lymphoma despite prior thoracic irradiation. It should consist of lumpectomy and adjuvant breast radiotherapy with use of adequate techniques, such as the lateral decubitus isocentric position.

Modeling of response to endocrine therapy in a panel of human luminal breast cancer xenografts

Resistance to endocrine therapy is a major complication of luminal breast cancer and studies of the biological features of hormonal resistance are limited by the lack of adequate preclinical models. The aim of this study is to establish and characterize a panel of primary human luminal breast carcinoma xenografts, and to evaluate their response to endocrine therapies. Four hundred and twenty-three tumor fragments obtained directly from patients have been grafted in the interscapular fatpad of Swiss nude mice. After stable engraftment with estradiol supplementation, xenografted tumors have been validated by conventional pathology and immunohistochemistry examination, and additional molecular studies. In vivo tumor growth and response to different endocrine treatments were evaluated. We have engrafted 423 tumors including 314 ER+ tumors, and 8 new luminal breast cancer xenografts have been obtained (2.5%). Tumor take was much lower for luminal tumors than for non-luminal tumors (2.5 vs. 24.7%, P < 0.0001), and was associated with two independent criteria, i.e., ER status (P < 0.0001) and a high grade tumor (P = 0.05). Histological and immunohistochemical analyses performed on patient's tumors and xenografts showed striking similarities in the tumor morphology as well as in the expression level of ER, PR, and HER2. Response to hormone therapy, evaluated in 6 luminal models, showed different sensitivities, thus exhibiting heterogeneity similar to what is observed in the clinic. We have established a panel of primary human luminal breast cancer xenografts, recapitulating the biological and clinical behaviors of patient tumors, and therefore suitable for further preclinical experiments.

Abstract S6-7: Establishment and Characterization of Human Luminal Breast Cancer Xenografts

Background: Despite an initial response to hormone therapy, luminal breast cancers (BC) are defined by a persisting long term risk of relapse. Preclinical models of estrogen-dependent human BC are therefore requested for a better understanding of estrogen receptor (ER) and hormone resistance biology. Because of a very low tumor take in immunodeficient mice, most in vivo models of estrogen-dependent human breast tumors are derived from human cancer cell lines. We report here the establishment and the characterization of new primary human luminal breast cancer xenografts directly obtained from fresh human tumor samples.

Methods: As of December 2009, 453 fresh human BC samples have been engrafted in the interscapular fatpad of nude mice, of which 405 were retained for further studies (32 were non infiltrating or non-breast carcinoma, and 16 were axillary metastatic lymph node from a simultaneously engrafted primay tumor). ER was expressed in 313 tumors (77.3%), progesterone receptor in 175/291 informative tumors (60.1%), Her2 in 39/315 tumors (12.4%), and 60 tumors were triple negative. After transplantation, mice were kept in a dedicated unit and fed with water containing estrogen. Validation of the xenografts was obtained by a large phenotypic and genotypic profiling including: pathological and immunohistochemical (IHC) examination, dedicated gene expression (RT-qPCR), genomic (BAC CGH arrays) and transcriptomic (Affymetrix u133 RNA chips) analyses, and therapeutic assessment (estrogen deprivation, ovariectomy, LHRH agonists, letrozole, tamoxifen, fulvestrant).

Results: Among the 405 human xenografted tumors, 8 luminal models have been established (2%), 7 from ER+/PR+ tumors and 1 from an axillary relapse of an ER-/HER2+ tumor. In all tumor/xenograft pairs, histopathological analyses showed an impressive morphological concordance. One had a strong mucinous component, and all of them were grade II/III tumors. Out of the 7 ER+/PR+ models, 3 were also HER2 positive. RNA expression by RT-qPCR confirmed ER, PR and HER2 status for the 7 ER+/ER+ tumors, and confirmed the ER+ status of the ER-/HER2+ derived tumorgraft. CGH arrays analyses demonstrated striking similarities of the genomic profile between the original tumors and their corresponding xenografts. Array CGH analyses were also performed at several passages, showing stable profile of the tumors during successive in vivo passages. Transcriptomic profile are still ongoing and will define each xenograft as either luminal A or B tumor subtypes. The tumor growth of all luminal BC models was estrogen dependent as demonstrated by estrogen supplementation and ovariectomy. Finally, therapeutic characterization of the xenografts showed that tamoxifen had a delayed but significant anti-tumor effect, whereas fulvestrant was the most efficient hormone therapy with durable complete responses observed in 3/3 evaluable models. Updated and extended results will be presented during the meeting.

Conclusions: We have durably established and characterized 8 primary human luminal BC xenografts. In order to identify new therapeutic approaches of hormone resistant BC, we have now planed to decipher in these well-defined preclinical models the molecular variations associated with emergence of resistance to hormone therapies

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S6-7.

Establishment and characterisation of a new breast cancer xenograft obtained from a woman carrying a germline BRCA2 mutation

Background:

The BRCA2 gene is responsible for a high number of hereditary breast and ovarian cancers, and studies of the BRCA2 biological functions are limited by the lack of models that resemble the patient's tumour features. The aim of this study was to establish and characterise a new human breast carcinoma xenograft obtained from a woman carrying a germline BRCA2 mutation.

Methods:

A transplantable xenograft was obtained by grafting a breast cancer sample into nude mice. The biological and genetic profiles of the xenograft were compared with that of the patient's tumour using histology, immunohistochemistry (IHC), BRCA2 sequencing, comparative genomic hybridisation (CGH), and qRT–PCR. Tumour response to standard chemotherapies was evaluated.

Results:

Histological profile identified the tumour as a basal-like triple-negative breast cancer. Targeted BRCA2 DNA sequencing of the xenograft showed the presence of the mutation previously identified in the carrier. Comparative genomic hybridisation array profiles of the primary tumour and the xenograft revealed a high number of similar genetic alterations. The therapeutic assessment of the xenograft showed sensitivity to anthracyclin-based chemotherapy and resistance to docetaxel. The xenograft was also highly sensitive to radiotherapy and cisplatin-based treatments.

Conclusions:

This study describes a new human breast cancer xenograft obtained from a BRCA2-mutated patient. This xenograft provides a new model for the pre-clinical drug development and for the exploration of the drug response biological basis.

A large multicentric study of gemcitabine-based regimen in relapsed or refractory Hodgkin lymphoma (HL) patients (pts)

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Background: The aim of this study was to assess the efficacy and safety of gemcitabine-based regimen in heavily pretreated HL pts. Methods: Relapsed or refractory HL pts treated with gemcitabine were retrospectively reviewed. Gemcitabine was used as a single agent or administered in combination with vinorelbine, oxaliplatine, doxorubicine, vinblastine, rituximab, and/or corticosteroids. Results: Fifty-five pts treated in 9 departments of clinical hematology between January 1999 and August 2006 were included in the study. Initial characteristics before gemcitabine administration were: nodular sclerosis in 84%; sex ratio M/F 1.1; median age 29 years (range: 15–85 years); advanced stage 84%; extranodal sites were lung, bone, liver, soft tissues, and bone marrow in 68%, 31%, 13%, 21%, and 4%, respectively; Hasenclever index lower than 3 in 20/43 cases (47%). At the end of the first front-line therapy (chemotherapy ± radiotherapy), 19 pts (35%) were in complete response (CR) in whom 13 relapsed within one year, 5 were in partial response (PR), and 31 pts were primary refractory (56%). Median number of previous chemotherapeutic regimen was 3 (range 1–8), 39 pts (71%) have received radiotherapy (RT), and 34 pts (62%) one or two autologous/allogenic stem cell transplantations (A/ASCT). Twenty-nine pts received gemcitabine alone with a median initial dose per injection of 750 mg/m2 (range: 180–1250 mg/m2); Gemcitabine was administered at an initial dose per injection of 1000 mg/m2 (range: 500–1250) in combination with vinorelbine in 10 pts, oxaliplatine in 13 pts in whom 4 with rituximab, and with others drugs in 3 pts. In both cases, the median number of combined gemcitabine regimen injections was 6 (range: 1–27). Toxicity was mainly hematological (75% of pts developed bi- or pancytopenia) or infectious (13%). Among all included pts, 6 were in CR (11%) and 5 in PR with an overall response rate of 20%. Among the 6 CR, 5 pts received thereafter A/ASCT and 2 pts RT, with 2 persistent CR at 16 and 44 months. In univariate analysis, none prognostic factor for response to gemcitabine was identified. Conclusions: This study, which constitutes one of the most important series, showed a mild efficacy of gemcitabine-based regimen in heavily pretreated HL patients.

No significant financial relationships to disclose.

Radioimmunotherapy (RIT) of refractory or relapsed Hodgkin’s lymphoma with 90Yttrium-labeled antiferritin antibody

2534

Background: The aims of this study were to evaluate (1) the tumor targeting of 111Indium-labeled rabbit polyclonal antiferritin antibody (Ab) and (2) the therapeutic efficacy of 90Yttrium-labeled antiferritin Ab in relapsed or refractory Hodgkin’s lymphoma (HL) patients (pts). Methods: After obtention of the patients’ consent, the protocol included a first intravenous injection of 2 mg of antiferritin Ab labeled to 111 MBq (3 mCi) of 111Indium followed by immunoscintigraphy at time 24 and 48 hours and, in case of tumor targeting, one or more intravenous injections of 90Yttrium-labeled antiferritin Ab at various activities. Results: Ten patients were included in the study: median age 32 years (range: 18–43 years); sex ratio M/F 9; stages III and IV at the time of RIT 1 and 9 pts, respectively; median number of chemotherapy regimens 3 (range: 2–4); number of autografted pts 8; number of previously irradiated pts 9; response to last chemotherapy: 6 PR and 4 progressions. All immunoscintigraphies showed a tumor targeting by 111Indium-labeled antiferritin Ab. Nine patients were treated, one case died of HL evolution. Five pts received one 90Yttrium-labeled antiferritin Ab injection, three pts 2 injections (0.5, 5 et 14 months after the first one), and one pt 4 injections (3, 9 et 16 months after the first one). Median injected activity was 13 MBq/kg (0.35 mCi/kg)(range: 7–15 MBq). Among the 9 treated pts, 1 CR, 6 PR, 1 stable disease, and 1 tumor progression were observed (ORR 78%). The median duration of responses were 8 months (range: 7–12 months). Toxicity was mainly hematological, with neutropenia and anemia of grades 1 or 2, and thrombopenia of grades 2 and 3; one pt presented a generalized convulsive crisis 24 hours after the therapeutic injection, without etiologic evidence. Conclusion: These results confirmed those that have been reported by Vriesendorp and Quadri and showed that rabbit polyclonal antiferritin Ab targeted HL tumor sites and had an important therapeutic potential in this discrepancy situation. They warranted therefore further multicentric prospective trials.

[Table: see text]

Low prevalence of Chlamydia psittaci infection in French patients with ocular adnexal lymphomas (OAL)

17536

Background: A high prevalence of Chlamydia psittaci infection in both tumor tissues and peripheral blood mononuclear cells of Italian patients with OAL has been reported (Ferreri AJ, Guidoboni M, Ponzoni M, De Conciliis C, Dell’Oro S, Fleischhauer K, et al. Evidence for an association between Chlamydia psittaci and ocular adnexal lymphomas. J Natl Cancer Inst 2004;96(8):586–94.) This association has not been confirmed in some regions of the USA, and no data from other European countries are available. We therefore investigated the presence of DNA of C. psittaci, C. trachomatis, and C. pneumoniae DNA in French patients (pts) with OAL. Methods: Tumor samples from ophthalmologic biopsies of 16 OAL pts (10 conjunctiva, 6 orbit) were included in the study. Histologic type were MALT-type (n = 8), lymphoplasmocytic (n = 6), follicular (n = 1), and diffuse large B-cell (n = 1) lymphomas. Two other groups of lymphoproliferative disease were analyzed as controls. First, ten cases of nodal lymphomas (follicular and marginal zone B-cell lymphomas), and ten cases of reactive lymphoid hyperplasia were analyzed. A multiplex touchdown, enzyme time-release PCR designed to simultaneously detect C. psittaci, C. pneumoniae and C. trachomatis DNA sequences was performed. PCR analyses were performed in duplicate in an independent setting either inat the Curie Institut Curie in e, Paris, and in the National Cancer Institute, Aviano. Results: DNA of C. psittaci DNA was detected in the tumoral tissue of only one patient with follicular OAL. No DNA sequences of C. psittaci, C. pneumoniae and C. trachomatis DNA sequences were was detected in all any of the other OALs, or controls. Conclusions: The prevalence of C. psittaci infection in French pts with OAL was sensibly significantly lower than that reported in Italian series. Cross-controls between the two laboratories indicate that this finding is not due to different experimental conditions. Discrepancies may be explained by an heterogeneous epidemiological distribution of the bacterial infection. Large studies aimed to investigate geographical variations in the prevalence of this association are warranted.

No significant financial relationships to disclose.

Multifocal neuropathy due to plasma cell infiltration of peripheral nerves in multiple myeloma

Patients with multiple myeloma (MM) can manifest a variety of neurologic complications. The authors report two patients who had development of a multifocal neuropathy related to infiltration of peripheral nerves by malignant plasma cells as the only manifestation of a relapse of MM, which was considered in full remission.

Protein toxins: intracellular trafficking for targeted therapy

The immunotoxin approach is based on the use of tumor-targeting ligands or antibodies that are linked to the catalytic (toxic) moieties of bacterial or plant protein toxins. In this review, we first discuss the current state of clinical development of immunotoxin approaches describing the results obtained with the two toxins most frequently used: diphtheria and Pseudomonas toxin-derived proteins. In the second part of the review, a novel concept will be presented in which the roles are inverted: nontoxic receptor-binding toxin moieties are used for the targeting of therapeutic and diagnostic compounds to cancer or immune cells. The cell biological basis of these novel types of toxin-based therapeutics will be discussed, and we will summarize ongoing preclinical and clinical testing.

Ex vivo expansion of megakaryocyte precursor cells in autologous stem cell transplantation for relapsed malignant lymphoma

To evaluate the impact of ex vivo expanded megakaryocyte (MK) progenitors on high-dose chemotherapy-induced thrombocytopenia, we conducted a phase II study in 10 patients with relapsed lymphoma. Two fractions of peripheral blood progenitor cells (PBPC) were cryopreserved, one with enough cells for at least 2 x 10(6) CD34+ cells/kg and a second obtained after CD34+ selection. Ten days before autologous stem cell transplantation, the CD34+ fraction was cultured with MGDF+SCF for 10 days. After BEAM (BCNU, cyclophosphamide, cytarabine, and melphalan) chemotherapy, patients were reinfused with standard PBPC and ex vivo expanded cells. No toxicity was observed after reinfusion. The mean fold expansion was 9.27 for nucleated cells, 2 for CD34+ cells, 676 for CD41+ cells, and 627 for CD61+ cells. The median date of platelet transfusion independence was day 8 (range: 7-12). All patients received at least one platelet transfusion. In conclusion, ex vivo expansion of MK progenitors was feasible and safe, but this procedure did not prevent BEAM-induced thrombocytopenia. Future studies will determine if expansion of higher numbers of CD34+ cells towards the MK-differentiation pathway will translate into a functional effect in terms of shortening of BEAM-induced thrombocytopenia.

Distinct experimental efficacy of anti-Fas/APO-1/CD95 receptor antibody in human tumors

Ligation of the Fas receptor (FasR) is a key step in apoptosis induction. Using a series of human tumor cells (SNB19, SNB79, 143N2, and SHEP), we observed a distinct efficacy of human anti-FasR antibody with an apparent correlation with Fas cell surface antigen expression. In contrast, all cells studied expressed detectable FasR mRNA transcripts. For all anti-FasR antibody-sensitive tumor cells, we showed a similar efficacy of Mab according to dose fractionation and injection site. We showed that, when injected into nude mice bearing human osteosarcoma 143N2, neuroblastoma SHEP, prostatic cancer PAC120, and the two glioblastomas SNB19 and SNB79, anti-FasR Mab induces significant inhibition of the growth rate of 143N2, SHEP, and PAC120 tumors, but has no efficacy on SNB19 and SNB79 tumors, with a relationship between in vitro and in vivo sensitivity to anti-FasR antibody. Altogether, these results suggest the antitumor potential of anti-FasR antibody in human neoplasms.

Mitochondrion as a novel target of anticancer chemotherapy

Mitochondrial membrane permeabilization is a critical event in the process leading to physiologic or chemotherapy-induced apoptosis (programmed cell death). This permeabilization event is, at least in part, under the control of the permeability transition pore complex (PTPC). Oncoproteins from the Bcl-2 family and tumor suppressor proteins from the Bax family interact with PTPC to inhibit or facilitate membrane permeabilization, respectively. Conventional chemotherapeutic agents elicit mitochondrial permeabilization in an indirect fashion by induction of endogenous effectors that are involved in the physiologic control of apoptosis. However, an increasing number of experimental anticancer drugs, including lonidamine, arsenite, betulinic acid, CD437, and several amphipathic cationic alpha-helical peptides, act directly on mitochondrial membranes and/or on the PTPC. Such agents may induce apoptosis in circumstances in which conventional drugs fail to act because endogenous apoptosis induction pathways, such as those involving p53, death receptors, or apical caspase activation, are disrupted. However, stabilization of the mitochondrial membrane by antiapoptotic Bcl-2-like proteins reduces the cytotoxic potential of most of these drugs. Targeting of specific PTPC components may overcome this Bcl-2-mediated apoptosis inhibition. One strategy involves cross-linking of critical redox-sensitive thiol groups within the PTPC; another involves the use of ligands to the mitochondrial benzodiazepine receptor. Thus, the design of mitochondrion-targeted cytotoxic drugs may constitute a novel strategy for overcoming apoptosis resistance.

Is mantle cell lymphoma a sex-related disease?

Mantle cell lymphomas are characterized by a male predominance with a range between 55 and 65 years (sex ratio M/F of 6.5). When the sex ratio of patients having mantle cell lymphoma was compared to that of each of the subtypes of non-Hodgkin's lymphomas, it was significantly higher in all cases except Burkitt's and lymphoblastic T-cell lymphomas. These observations suggest a possible relation between the chromosome X and mantle cell lymphomas which has to be explored.

Efficacy of autologous stem cell transplantation in mantle cell lymphoma: a 3-year follow-up study

This study was designed to evaluate the efficacy of therapeutic intensification with autologous stem cell transplantation (ASCT) for mantle cell lymphomas (MCL) in terms of response rate, duration of response, and event-free and overall survivals. Twenty-four patients with confirmed MCL responding to chemotherapy received a high-dose chemo-radiotherapy regimen followed by ASCT. Transplantation was performed during first-line therapy in nine cases, second-line in 13 cases and third-line in two cases. The source of hematopoietic stem cells was peripheral blood for 19 cases. At the time of ASCT, eight patients were in complete remission (33%). Seventeen of the 24 cases received an intensified regimen with TBI and seven received the BEAM or the BEAC regimen. After transplantation, 19 patients were in CR (79%). Nine of these were alive in continued CR at a median follow-up of 34 months, while seven relapsed at a median of 18 months. One patient died from Pneumocystis carinii interstitial pneumonitis and five patients developed secondary malignancies. With a median follow-up after transplantation of 34 months, the 3-year event-free survival was 55% and the 3-year overall survival was 68%. These results indicate that therapeutic intensification with ASCT might be an effective treatment for mantle cell lymphomas. Bone Marrow Transplantation (2000) 25, 251-256.

Low-grade stage III-IV follicular lymphoma: multivariate analysis of prognostic factors in 484 patients--a study of the groupe d'Etude des lymphomes de l'Adulte

PURPOSE

To identify the prognostic factors that influence overall survival (OS) in patients with stage III-IV follicular lymphomas and evaluate the clinical usefulness and the prognostic value of the International Prognostic Index (IPI).

PATIENTS AND METHODS

Four hundred eighty-four patients with Ann Arbor stage III-IV follicular lymphomas treated in two phase III trials from 1986 to 1995 were screened for this study. All histologic slides were reviewed by two hematopathologists. The influence of the initial parameters on survival was defined by univariate (log-rank test) and multivariate (Cox model) analyses.

RESULTS

The poor prognostic factors for OS (age > 60 years, "B" symptom(s), > or = two extranodal sites, stage IV disease, tumor bulk > 7 cm, at least three nodal sites > 3 cm, liver involvement, serous effusion-compression or orbital/epidural involvement, and erythrocyte sedimentation rate > 30 mm/h) that were significant in univariate analysis were subjected to multivariate analysis. Three factors remained significant: B symptom(s) (risk ratio = 1.80), age greater than 60 years (risk ratio = 1.60), and at least three nodal sites greater than 3 cm (risk ratio = 1.71). When the IPI was applied to these patients, the score was 1, 2, 3, and 4-5 in 49%, 39%, 11%, and 2%, respectively, and it was significant for progression-free survival (P =.002) and OS (P =.0001).

CONCLUSION

Three prognostic factors for poor OS were identified: B symptoms, age greater than 60 years, and at least three nodal sites greater than 3 cm. The IPI was prognostic for OS, but in this population, a very low number of patients belonged to the high-risk groups.

Arsenite induces apoptosis via a direct effect on the mitochondrial permeability transition pore

The molecular mode of action of arsenic, a therapeutic agent employed in the treatment of acute promyelocytic leukemia, has been elusive. Here we provide evidence that arsenic compounds may act on mitochondria to induce apoptosis. Arsenite induces apoptosis accompanied by a loss of the mitochondrial transmembrane potential (Delta Psim). Inhibition of caspases prevents the arsenite-induced nuclear DNA loss, but has no effect on the Delta Psim dissipation and cytolysis induced by arsenite. In contrast, Bcl-2 expression induced by gene transfer prevents all hallmarks of arsenite-induced cell death, including the Delta Psim collapse. PK11195, a ligand of the mitochondrial benzodiazepine receptor, neutralizes this Bcl-2 effect. Mitochondria are required in a cell-free system to mediate arsenite-induced nuclear apoptosis. Arsenite causes the release of an apoptosis-inducing factor (AIF) from the mitochondrial intermembrane space. This effect is prevented by the permeability transition (PT) pore inhibitor cyclosporin A, as well as by Bcl-2, which is known to function as an endogenous PT pore antagonist. Arsenite also opens the purified, reconstituted PT pore in vitro in a cyclosporin A- and Bcl-2-inhibitible fashion. Altogether these data suggest that arsenite can induce apoptosis via a direct effect on the mitochondrial PT pore.

PK11195, a ligand of the mitochondrial benzodiazepine receptor, facilitates the induction of apoptosis and reverses Bcl-2-mediated cytoprotection

One critical step of the apoptotic process is the opening of the mitochondrial permeability transition (PT) pore leading to the disruption of mitochondrial membrane integrity and to the dissipation of the inner transmembrane proton gradient (Delta Psim). The mitochondrial PT pore is a polyprotein structure which is inhibited by the apoptosis-inhibitory oncoprotein Bcl-2 and which is closely associated with the mitochondrial benzodiazepine receptor (mBzR). Here we show that PK11195, a prototypic ligand of the 18-kDa mBzR, facilitates the induction of Delta Psim disruption and subsequent apoptosis by a number of different agents,including agonists of the glucocorticoid receptor,chemotherapeutic agents (etoposide, doxorubicin),gamma irradiation, and the proapoptotic second messenger ceramide. Whereas PK11195 itself has no cytotoxic effect, it enhances apoptosis induction by these agents. This effect is not observed for benzodiazepine diazepam, whose binding site in the mBzR differs from PK11195. PK11195 partially reverses Bcl-2 mediated inhibition of apoptosis in two different cell lines. Thus, transfection-enforced Bcl-2 overexpression confers protection against glucocorticoids and chemotherapeutic agents, and this protection is largely reversed by the addition of PK11195. This effect is observed at the level of Delta Psim dissipation as well as at the level of nuclear apoptosis. To gain insights into the site of action of PK11195, we performed experiments on isolated organelles. PK11195 reverses the Bcl-2-mediated mitochondrial retention of apoptogenic factors which cause isolated nuclei to undergo apoptosis in a cell-free system. Mitochondria from control cells, but not mitochondria from Bcl-2-overexpressing cells, readily release such apoptogenic factors in response to atractyloside, a ligand of the adenine nucleotide translocator. However, control and Bcl-2-overexpressing mitochondria respond equally well to a combination of atractyloside and PK11195. Altogether, these findings indicate that PK11195 abolishes apoptosis inhibition by Bcl-2 via a direct effect on mitochondria. Moreover, they suggest a novel strategy for enhancing the susceptibility of cells to apoptosis induction and, concomitantly, for reversing Bcl-2-mediated cytoprotection.

VIP (etoposide, ifosfamide and cisplatinum) as a salvage intensification program in relapsed or refractory Hodgkin's disease

Forty-two patients with refractory (15 patients) or relapsed (27 patients) Hodgkin's disease (HD) were included in a prospective single center study evaluating the efficacy of a regimen VIP combining etoposide 75 mg/m2/day days 1-5, ifosfamide 1.2 g/m2/day days 1-5 and cisplatinum 20 mg/m2/day days 1-5, one course every 4 weeks as salvage therapy in patients with refractory or relapsed Hodgkin's disease, potentially eligible for high-dose chemotherapy with reinjection of hematopoietic stem cells (HSC). If patients were considered chemosensitive after two courses of VIP, high-dose chemotherapy followed by the reinjection of HSC was planned. After two courses of VIP, 67% achieved an objective response including 38% complete responses. Overall, 28 patients went on to high-dose therapy with reinjection of HSC, and 46% of grafted patients are in a sustained complete remission. When the overall patient population is considered, 33% are in complete remission (CR) with a median follow-up of 37 months. A CR of less than 12 months and refractory disease were associated with a poor survival. These results showed that the VIP regimen is effective in relapsed or refractory HD and allows high-dose therapy to be given in the case of most responding patients. However, results in patients with refractory disease or a first complete remission of less than 12 months need to be further improved.