Mechanism of action of chlormethine gel in mycosis fungoides.

Mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma, is characterized by proliferation of malignant skin-tropic T cells. Progression from early-stage disease (skin patches and/or plaques) to more advanced stages (cutaneous tumours, erythroderma or extracutaneous involvement) occurs slowly and can be discontinuous. Prognosis is poor for the ~25% of patients who progress to advanced disease. Patients at any stage of MF may experience reduced health-related quality of life (QoL) via a spectrum of physically and psychologically debilitating symptoms that can impact many aspects of daily life. Allogeneic stem-cell transplantation is a curative treatment option for some patients with advanced disease, but otherwise there is currently no cure for MF; patients are often refractory to several treatments and require lifelong management. The goals of therapy are symptom control, prevention of disease progression, avoidance of treatment-related toxicity and maintenance/improvement of QoL. Although treatment regimens exist it can be difficult to know how to prioritize them, hence therapies are tailored according to patient needs and drug availabilities, following clinical recommendations. International consensus guidelines recommend skin-directed therapies (SDTs) as first-line treatment for early-stage disease, and SDTs combined with systemic therapy for advanced stages. Chlormethine (CL), also known as mechlorethamine, chlorethazine, mustine, HN2, caryolysine and embichin, is a synthetic deoxyribonucleic acid-alkylating agent that was used as a chemical weapon (mustard gas) during the First World War. Subsequent investigation revealed that survivors of mustard gas exposure had lymphocytopenia, and that CL could inhibit rapidly proliferating malignant T cells. CL has since been developed as a topical treatment for MF and prescribed as such for over 70 years. This review aims to summarize the current knowledge regarding the mechanism of action of CL in the cutaneous micro-environment, in the specific context of MF treatment.

Chlormethine Gel for the Treatment of Mycosis Fungoides (Cutaneous T-cell Lymphoma) in Canada.

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma (CTCL), representing almost 50% of all lymphomas arising in the skin. There is an unmet need in the treatment of MF in Canada, as current available therapies for early-stage MF are limited, without topical agents previously indicated. Chlormethine gel is a topical antineoplastic agent with phase II clinical trial and real-world data demonstrating safety and efficacy as a treatment option for adults with MF. Skin-related side effects such as dermatitis can be managed through appropriate strategies. The use of chlormethine gel can be considered for patients with stage IA and IB MF-CTCL as it provides an easily administered, skin-directed treatment option that fills an unmet need in Canada.

MG53 attenuates nitrogen mustard-induced acute lung injury.

Nitrogen mustard (NM) is an alkylating vesicant that causes severe pulmonary injury. Currently, there are no effective means to counteract vesicant-induced lung injury. MG53 is a vital component of cell membrane repair and lung protection. Here, we show that mice with ablation of MG53 are more susceptible to NM-induced lung injury than the wild-type mice. Treatment of wild-type mice with exogenous recombinant human MG53 (rhMG53) protein ameliorates NM-induced lung injury by restoring arterial blood oxygen level, by improving dynamic lung compliance and by reducing airway resistance. Exposure of lung epithelial and endothelial cells to NM leads to intracellular oxidative stress that compromises the intrinsic cell membrane repair function of MG53. Exogenous rhMG53 protein applied to the culture medium protects lung epithelial and endothelial cells from NM-induced membrane injury and oxidative stress, and enhances survival of the cells. Additionally, we show that loss of MG53 leads to increased vulnerability of macrophages to vesicant-induced cell death. Overall, these findings support the therapeutic potential of rhMG53 to counteract vesicant-induced lung injury.

Topical chlormethine gel in the treatment of mycosis fungoides: A single-center real-life experience and systematic review of the literature.

Gel formulation of chlormethine (CG) has gained a preeminent role among therapies available for mycosis fungoides (MF). To evaluate the frequency of use of CG for MF treatment and to determine the limits and potentialities of CG in a real-world setting. A systematic review of articles published prior to October 2021 was performed. Articles were included in the review if a full-text English version was available. MEDLINE (PubMed), Scopus, and Web of Science were each queried from their date of inception with the following terms: "mechlorethamine gel", "chlormethine gel", and "mycosis fungoides". The reference lists of the studies retrieved were searched manually. Moreover, this study included all consecutive patients with different stages of MF (from IA to IIB) who started treatment with CG gel between July 2020 and May 2021. Data of the literature were compared to our single-center real-life experience. Of the surveyed literature, 11 publications were included in the final analysis describing a total of 548 patients with MF. Eleven patients with a median (standard deviation) age of 66 years (15.1) were enrolled and followed up, receiving CG (0.02% chlormethine HCl). Response to treatment resulted higher (90.1%) in our study population than in other real-world experiences published in literature. This systematic review supports the role of CG for MF treatment, showing its limits and potentialities. Our single-center real-life experience revealed an elevated percentage of clinical response with high safety and tolerance, demonstrating its versatile use with dose and application rate adaptability.

Chlormethine Hydrochloride is Not Inferior to Tacrolimus in Treating Steroid-Resistant Nephrotic Syndrome.

BACKGROUND/AIMS: The present study aimed to explore the equivalence of CHL and tacrolimus (TAC), despite reports regarding the efficacy and safety of TAC in treating SRNS patients. METHODS: A retrospective cohort study of CHL or TAC treatment was performed by collecting the medical records of SRNS patients with a pathological classification of focal segmental glomurular sclerosis (FSGS) or membranous nephropathy (MN) from December 2008 to December 2014 in a 3A grade hospital in southern China. The treatment regimen includes 6 months of induction therapy and a subsequent 6 to 30 months of maintenance therapy, which were evaluated by the scheduled follow-up and the detection of proteinuria and serum creatinine levels. The treatment outcomes were classified as complete remission, partial remission or no remission. RESULTS: In a total of 146 SRNS patients, CHL treatment showed a higher proportion of complete remission (27.8% vs 14.9%) or partial remission (52.8% vs 37.8%) compared to TAC treatment (P < 0.10) at the stage of induction therapy. The CHL treatment of SRNS patients with FSGS showed better efficacy than treatment of the TAC group, but the difference of efficacy in the pathological type of MN between CHL and TAC group was not significant (P > 0.10). During maintenance therapy, the difference between the CHL and TAC groups was not significant in the SRNS patients with FSGS or MN (P > 0.10). In addition, the difference of adverse effects between CHL and TAC group was not significant (P > 0.10), although there was a slightly higher proportion of nausea and vomiting in the CHL group. CONCLUSION: The non-inferior efficacy of CHL treatment on the SRNS patients with FSGS or MN compared to TAC treatment, which highlighted CHL can be considered to be alternative treatment for SRNS patients in the clinical setting.

Infradiaphragmatic irradiation and high procarbazine doses increase colorectal cancer risk in Hodgkin lymphoma survivors.

BACKGROUND: Hodgkin lymphoma (HL) survivors are at increased risk of second malignancies, but few studies have assessed colorectal cancer (CRC) risk after HL treatment. We assessed long-term, subsite-specific CRC risk associated with specific radiation fields and chemotherapy regimens. METHODS: In a Dutch cohort of 3121 5-year HL survivors treated between 1965 and 1995, subsite-specific CRC incidence was compared with general population rates. Treatment effects were quantified by Cox regression analyses. RESULTS: After a median follow-up of 22.9 years, 55 patients developed CRC. The standardized incidence ratios (SIR) was 2.4-fold increased (95% confidence interval (95%CI) 1.8-3.2), leading to 5.7 excess cases per 10 000 patient-years. Risk was still increased 30 years after HL treatment (SIR: 2.8; 95%CI: 1.6-4.6). The highest (SIR: 6.5, 95%CI: 3.3-11.3) was seen for transverse colon cancer (15.0 (95%CI: 4.3-40.8) after inverted-Y irradiation). A prescribed cumulative procarbazine dose >4.2 g m-2 was associated with a 3.3-fold higher CRC risk (95%CI: 1.8-6.1) compared to treatment without procarbazine. Patients receiving >4.2 g m-2 procarbazine and infradiaphragmatic radiotherapy had a hazard ratio of 6.8 (95%CI: 3.0-15.6) compared with patients receiving neither treatment, which is significantly higher than an additive joint effect (Padditivity=0.004). CONCLUSIONS: Colorectal cancer surveillance should be considered for HL survivors who received Infradiaphragmatic radiotherapy and a high cumulative procarbazine dose.

Hodgkin lymphoma: MOPP chemotherapy to PD-1 blockade and beyond.

Hodgkin lymphoma is a rare lymphoid malignancy affecting ∼9,200 new patients in the United States annually. Progress in the management of this disease over the past 50 years has been remarkable and the prognosis of this malignancy has changed from a uniformly fatal process to one in which the vast majority of patients are expected to be cured. This remarkable progress has been due to the use of combination approaches incorporating chemotherapy and radiation therapy, and now more recently antibody-drug conjugates and immune checkpoint inhibitors. The goal for the future is to develop treatment combinations that successfully treat all patients and markedly decrease the long-term side effects.

Plasma Epstein-Barr virus DNA predicts outcome in advanced Hodgkin lymphoma: correlative analysis from a large North American cooperative group trial.

Epstein-Barr virus (EBV) is associated with Hodgkin lymphoma (HL) and can be detected by in situ hybridization (ISH) of viral nucleic acid (EBER) in tumor cells. We sought to determine whether plasma EBV-DNA could serve as a surrogate for EBER-ISH and to explore its prognostic utility in HL. Specimens from the Cancer Cooperative Intergroup Trial E2496 were used to compare pretreatment plasma EBV-DNA quantification with EBV tumor status by EBER-ISH. A cutoff of >60 viral copies/100 µL plasma yielded 96% concordance with EBER-ISH. Pretreatment and month 6 plasma specimens were designated EBV(-) or EBV(+) by this cutoff. Patients with pretreatment EBV(+) plasma (n = 54) had inferior failure-free survival (FFS) compared with those with pretreatment EBV(-) plasma (n = 274), log-rank P = .009. By contrast, no difference in FFS was observed when patients were stratified by EBER-ISH. Pretreatment plasma EBV positivity was an independent predictor of treatment failure on multivariate analyses. At month 6, plasma EBV(+) patients (n = 7) had inferior FFS compared with plasma EBV(-) patients (n = 125), log-rank P = .007. These results confirm that plasma EBV-DNA is highly concordant with EBER-ISH in HL and suggest that it may have prognostic utility both at baseline and after therapy. This trial was registered at www.clinicaltrials.gov as #NCT00003389.

Concomitant mycosis fungoides and vitiligo: how mycosis fungoides may contribute to melanocyte destruction.

BACKGROUND: Few reports have described vitiligo developing in patients with cutaneous T-cell lymphoma (CTCL). OBJECTIVE: We sought to identify possible factors that might predispose patients with CTCL to vitiligo. METHODS: Patient demographics, CTCL disease characteristics and treatments were analyzed in 25 patients with CTCL who developed vitiligo. Cox proportional hazards modeling was used to identify associations of risk factors with the development of vitiligo. RESULTS: Younger age, later CTCL disease stage (stages IIB-IV) and presence of a CD8+CD4- mycosis fungoides phenotype were associated with the development of vitiligo. After adjusting for disease stage, increased risk of vitiligo was associated with methotrexate and CD4 antibody therapies (although the total number of patients with these was small), while decreased risk was associated with nitrogen mustard and PUVA therapies. CONCLUSIONS: No single feature was common to all of our patients, suggesting that multiple factors may contribute to the development of vitiligo in a patient-specific fashion.

Primary cutaneous T-cell lymphoma (mycosis fungoides and Sézary syndrome): part II. Prognosis, management, and future directions.

Both mycosis fungoides (MF) and Sézary syndrome (SS) have a chronic, relapsing course, with patients frequently undergoing multiple, consecutive therapies. Treatment is aimed at the clearance of skin disease, the minimization of recurrence, the prevention of disease progression, and the preservation of quality of life. Other important considerations are symptom severity, including pruritus and patient age/comorbidities. In general, for limited patch and plaque disease, patients have excellent prognosis on ≥1 topical formulations, including topical corticosteroids and nitrogen mustard, with widespread patch/plaque disease often requiring phototherapy. In refractory early stage MF, transformed MF, and folliculotropic MF, a combination of skin-directed therapy plus low-dose immunomodulators (eg, interferon or bexarotene) may be effective. Patients with advanced and erythrodermic MF/SS can have profound immunosuppression, with treatments targeting tumor cells aimed for immune reconstitution. Biologic agents or targeted therapies either alone or in combination--including immunomodulators and histone-deacetylase inhibitors--are tried first, with more immunosuppressive therapies, such as alemtuzumab or chemotherapy, being generally reserved for refractory or rapidly progressive disease or extensive lymph node and metastatic involvement. Recently, an increased understanding of the pathogenesis of MF and SS with identification of important molecular markers has led to the development of new targeted therapies that are currently being explored in clinical trials in advanced MF and SS.

Evaluating Response Trends of Chlormethine/Mechlorethamine Gel in Patients With Stage I-IIA Mycosis Fungoides: Analysis of Individual Patient Data From a Randomized Controlled Phase II Study to Facilitate Optimal Treatment Experiences.

INTRODUCTION: Chlormethine (CL) gel was approved for treatment of mycosis fungoides based on the pivotal 201 trial (NCT00168064). Data visualization from individual patients is a powerful tool for discovery of hidden treatment trends. Here, we present a post hoc analysis of individual patient data from the pivotal trial to provide a more granular depiction of treatment and response changes over time, with an emphasis on end of treatment status. MATERIALS AND METHODS: Individual patient response data were plotted over a 12-month treatment period to visualize patient experiences while using CL gel. Responder status was assigned according to end-of-treatment Composite Assessment of Index Lesion Severity (CAILS) score, and patients were classified as early (≤4 months) or late responders based on timing of response. Baseline and active treatment characteristics were compared between early and late responders, and baseline body surface area (BSA) was compared between responders and patients with stable or progressive disease. RESULTS: Data from 123 patients with baseline and postbaseline results were included. At the end of treatment, 64.2%/55.3% were responders, 30.9%/34.1% had stable disease, and 4.9%/10.6% had progressive disease by CAILS and mSWAT, respectively. Among patients who responded to treatment, 64.6% and 35.4% were early and late responders, respectively. Response pattern analysis also identified patients with an intermittent response or initial progressive disease. Baseline BSA was not associated with responder status. Late responders had longer treatment duration and higher postbaseline plaque elevation, while early responders had a higher frequency of dermatitis. CONCLUSIONS: Results presented here can facilitate optimal treatment experiences for patients starting CL gel.

Topical nitrogen mustard therapy in patients with mycosis fungoides or parapsoriasis.

BACKGROUND: Topical nitrogen mustard is a chemotherapeutic agent used in treatment of mycosis fungoides (MF). OBJECTIVE: To evaluate the response and side effects in patients with MF and parapsoriasis treated with topical nitrogen mustard. METHODS: A retrospective study of treatment response in 116 patients diagnosed with MF and 71 patients with parapsoriasis and treated with topical nitrogen mustard from 1991 to 2009. RESULTS: Overall response rate and complete response (CR) rate was 91.4% and 53.4% in patients with MF and 90.1% and 40.8% in patients with parapsoriasis, respectively. Relapse following CR was observed in 67.7% in patients with MF and 62.1% in patients with parapsoriasis. Freedom-from-relapse was higher in patients with T1-T2 than in T3 disease (P < 0.01). Progressive disease (PD) occurred in 25.0% and 26.8% in patients with MF and parapsoriasis, respectively. Progression-free survival was similar in patients with T1-T2 compared with T3 (P = 0.79) and T4 disease (P = 0.22) and lower in patients with parapsoriasis with <10% than >10% skin involvement (P = 0.05). CONCLUSION: The present study confirms that topical nitrogen mustard is a safe and effective therapy. The treatment response in patients with parapsoriasis was not statistically different from the response in patients with MF. This supports, that parapsoriasis is not a distinct entity, but an early stage of MF. Nitrogen mustard should therefore still be considered as an important treatment modality in patients with early stages (parapsoriasis) and later stages of MF either as monotherapy or in combination with other topical or systemic therapies.

An oxygen-carrying and lysosome-targeting BODIPY derivative for NIR bioimaging and enhanced multimodal therapy against hypoxic tumors.

Cancer treatment modalities have gradually shifted from monotherapies to multimodal therapies. It is still a challenge to develop a synergistic chemo-phototherapy system with relieving tumor hypoxia, specific targeting, and real-time fluorescence tracking. In this study, we designed a multifunctional BODIPY derivative, FBD-M, for synergistic chemo-phototherapy against hypoxic tumors. FBD-M was composed of four parts: 1) The BODIPY fluorophore selected as a theranostic core, 2) A pentafluorobenzene group modified on meso-BODIPY to carry oxygen, 3) A morpholine group hooked to one side of BODIPY served as a lysosome-targeting unit for enhancing antitumor effect, and 4) An aromatic nitrogen mustard group introduced on other side of BODIPY to achieve chemotherapy. After introducing the morpholine and aromatic nitrogen mustard in BODIPY, the conjugate system of BODIPY was also expanded to realize near-infrared (NIR) phototherapy. Finally, FBD-M was obtained by a rational design, which possessed with NIR absorbance and emission, photosensitive activity, oxygen-carrying capability for relieving tumor hypoxia, high photothermal conversion efficiency, good photostability, lysosome targeting, low toxicity, and synergistic chemo-phototherapy against hypoxic tumors. FBD-M had been successfully applied for anticancer in vitro and in vivo. Our study demonstrates that FBD-M can serve as an ideal multifunctional theranostic agents.

Evaluation of mechlorethamine, vinblastine, procarbazine, and prednisone for the treatment of resistant multicentric canine lymphoma.

Multi-agent chemotherapy successfully induces remission in most naïve, high-grade canine lymphoma patients; however, disease recurrence is common. MOPP (mechlorethamine, vincristine, procarbazine, and prednisone) is an effective rescue protocol used to re-induce remission, but is associated with gastrointestinal toxicity and can be a less desirable option for patients that previously failed vincristine-containing protocols. Therefore, alternative members of the vinca alkaloid family, such as vinblastine, could be potentially advantageous as substitutes for vincristine to reduce gastrointestinal toxicity and chemoresistance. The objective of this study was to report the clinical outcomes and toxicity of 36 dogs with relapsed or refractory multicentric lymphoma treated with a modified MOPP protocol whereby vincristine was replaced with vinblastine (MVPP). The overall response rate to MVPP was 25% with a median progression free survival of 15 days and a median overall survival of 45 days. MVPP at the prescribed doses resulted in modest and transient clinical benefit, but was well tolerated with no treatment delays or hospitalizations secondary to side effects. Given the minimal toxicity, dose intensification could be considered to improve clinical responses.

[Clinical analysis of childhood and adolescent Hodgkin's lymphoma: a report of 88 cases].

OBJECTIVE: The aim of this study was to investigate the clinicopathological characteristics, effective treatment and prognosis in childhood and adolescent Hodgkin's lymphoma. METHODS: A total of 88 patients with childhood and adolescent Hodgkin's lymphoma were treated in the Cancer Hospital of CAMS from 1998 to 2005. The clinicopathological and follow-up data of the patients were retrospectively reviewed. The survival rate was calculated by Kaplan-Meier method and compared by log-rank test. COX multivariate prognosis analysis was performed. RESULTS: The 2-year event-free survival rate of the 88 patients was 86.4%, the 5-year event-free survival rate was 61.4%, and the 5-year overall survival rate was 95.5%. Univariate analysis showed that the stage of disease (P = 0.033), "B" symptoms (P = 0.028), bulky disease (P = 0.007), splenomegaly (P = 0.050), LDH elevation (P = 0.020), chemotherapy regimen (P = 0.003) were prognostic factors in the 5-year event-free survival rate. Splenomegaly (P = 0.039), LDH elevation (P = 0.033), chemotherapy regimen (P = 0.008) were prognostic factors of 5-year overall survival rate. Multivariate analysis showed that chemotherapy regimen (P = 0.033), stage of disease (P = 0.023), LDH elevation (P = 0.008), "B" symptoms (P = 0.044), bulky disease (P = 0.009) were independent prognostic factors of 5-year event-free survival rate. The chemotherapy regimen (P = 0.012) and LDH elevation (P = 0.046) were independent prognostic factors of 5-year overall survival rate. CONCLUSIONS: The non-ABVD chemotherapy regimen, stage IV disease, LDH elevation, associated with "B" symptoms and bulky disease are independent prognostic factors of 5-year event-free survival rate. LDH elevation and non-ABVD chemotherapy regimen are independent prognostic factors of 5-year overall survival rate.

Response to Chlormethine/Mechlorethamine gel Maintenance Treatment Regimen in Patients With Mycosis Fungoides: A Single-center Retrospective Study.

BACKGROUND: Mycosis fungoides (MF), the most common subtype of Cutaneous T-cell lymphomas, is caused by malignant T-cell proliferations in the skin that can invade blood, lymph nodes, or viscera. Currently, data on efficacy of maintenance therapies in MF are lacking. We developed a unique protocol to use chlormethine/mechlorethamine 0.016% gel formulation as maintenance regimen for MF patients in remission. PURPOSE: To determine progression-free survival and efficacy of chlormethine/mechlorethamine as maintenance and active treatment regimens for MF. MATERIALS AND METHODS: A retrospective review of MF patients seen at Thomas Jefferson University from 2012 to 2020 was conducted. Patients of all stages treated with chlormethine/mechlorethamine as maintenance or active treatment with 2 consecutive mSWATs (modified Severity Weighted Assessment Tool) documented were included. Treatment outcomes were assessed by change in mSWAT and progression-free survival. Dermatology Life Quality Index surveys before and after treatment were analyzed. RESULTS: Of 186 MF patients, 44 met inclusion criteria. Patients on maintenance therapy had a 65.22% progression-free survival rate with median time to progression of 29.45 months. By-time analysis for responders on active and maintenance treatment showed an increased response over time. Peak responses were seen at last mSWAT recorded. Both cohorts experienced improved quality-of-life scores from initiation to discontinuation of chlormethine/mechlorethamine. CONCLUSION: Patients on maintenance and active chlormethine/mechlorethamine treatment regimens demonstrated improvement in mSWAT and quality-of-life. Chlormethine/mechlorethamine treatment showed progression-free survival for a median of 29.45 months, indicating this therapy may be an effective maintenance regimen.

Hodgkin Lymphoma on Hemodialysis: A Review of Treatment and Recommendations.

Chemotherapy for classic Hodgkin lymphoma (cHL) patients on hemodialysis (HD) is an extremely challenging situation because pharmacokinetic and pharmacodynamic studies of most chemotherapeutics are lacking for the HD patient, and the small amount of evidence available comes mostly from case reports and small case series. In this review, we provide recommendations based on treatment experience of cHL patients on HD in the literature. HD patients undergoing chemotherapy are at risk of overdose and toxicities because many drugs are significantly eliminated by the kidneys, and at the same time, are at risk of undertreatment because many drugs are removed by HD. Therefore, dose modifications and timing of drug administration in relation to HD sessions must be carefully planned according to the distinct traits of each chemotherapeutic. We carried out an exhaustive literature review of reports of actual administrations of chemotherapeutics to cHL on HD, and also extrapolated data from reports of the same chemotherapeutics that were administered to HD patients with malignancies other than cHL. We summarized the information found in the literature, and provide practical and balanced recommendations concerning dose modifications and optimal timing of drug administration in relation to HD sessions for each chemotherapeutic. Chemotherapy regimens and individual chemotherapeutics studied in this review include ABVD (doxorubicin + bleomycin + vinblastine + dacarbazine), BEACOPP (bleomycin + etoposide + doxorubicin + cyclophosphamide + vincristine + procarbazine + prednisolone), MOPP (mechlorethamine + vincristine + procarbazine + prednisolone), gemcitabine, vinorelbine, brentuximab vedotin, and PD-1 inhibitors (nivolumab and pembrolizumab).

Alkylating Agents, the Road Less Traversed, Changing Anticancer Therapy.

Cancer is considered one of the gruelling challenges and poses a grave health hazard across the globe. According to the International Agency for Research on Cancer (IARC), new cancer cases increased to 18.1 million in 2018, with 9.6 million deaths, bringing the global cancer rate to 23.6 million by 2030. In 1942, the discovery of nitrogen mustard as an alkylating agent was a tremendous breakthrough in cancer chemotherapy. It acts by binding to the DNA, and creating cross linkages between the two strands, leading to halt of DNA replication and eventual cell death. Nitrogen lone pairs of 'nitrogen mustard' produce an intermediate 'aziridinium ion' at the molecular level, which is very reactive towards DNA of tumour cells, resulting in multiple side effects with therapeutic consequences. Owing to its high reactivity and peripheral cytotoxicity, several improvements have been made with structural modifications for the past 75 years to enhance its efficacy and improve the direct transport of drugs to the tumour cells. Alkylating agents were among the first non-hormonal substances proven to be active against malignant cells and also the most valuable cytotoxic therapies available for the treatment of leukaemia and lymphoma patients. This review focus on the versatile use of alkylating agents and the Structure Activity Relationship (SAR) of each class of these compounds. This could provide an understanding for design and synthesis of new alkylating agents having enhanced target specificity and adequate bioavailability.

Alkylating antitumor drug mechlorethamine conceals a structured PrP domain and inhibits in vitro prion amplification.

Prion diseases are a group of incurable transmissible neurodegenerative disorders. The key molecular event in the pathogenesis of prion diseases is the conversion of the cellular prion protein (PrP(C)) into its pathological isoform (PrP(Sc)), accompanied by a conformational transition of α-helix into ß-sheet structure involving the structured α-helix 1 domain from residues 144-154 of the protein (PrP144-154). Blocking the accessibility of PrP144-152 with anti-PrP antibody 6H4 was found to prevent PrP conversion and even to cure prion infection in cell models ( Enari et al. 2001 ). Previously, Yuan et al. (2005 ) demonstrated that the reduction and alkylation of PrP induced concealment of the 6H4 epitope. This study examined the ability of mechlorethamine (MCT), an alkylating antitumor drug, to conceal the 6H4 epitope and block PrP conversion in the presence of a reducing reagent. Mechlorethamine treatment significantly decreased in vitro amplification of PrP(Sc) in the highly efficient protein misfolding cyclic amplification system. Our findings suggest that MCT may serve as a potential therapeutic agent for prion diseases.