Kikkeri N. Naresh

Clinical drug resistance linked to interconvertible phenotypic and functional states of tumor-propagating cells in multiple myeloma

The phenotype and function of cells enriched in tumor-propagating activity and their relationship to the phenotypic architecture in multiple myeloma (MM) are controversial. Here, in a cohort of 30 patients, we show that MM composes 4 hierarchically organized, clonally related subpopulations, which, although phenotypically distinct, share the same oncogenic chromosomal abnormalities as well as immunoglobulin heavy chain complementarity region 3 area sequence. Assessed in xenograft assays, myeloma-propagating activity is the exclusive property of a population characterized by its ability for bidirectional transition between the dominant CD19(-)CD138(+) plasma cell (PC) and a low frequency CD19(-)CD138(-) subpopulation (termed Pre-PC); in addition, Pre-PCs are more quiescent and unlike PCs, are primarily localized at extramedullary sites. As shown by gene expression profiling, compared with PCs, Pre-PCs are enriched in epigenetic regulators, suggesting that epigenetic plasticity underpins the phenotypic diversification of myeloma-propagating cells. Prospective assessment in paired, pretreatment, and posttreatment bone marrow samples shows that Pre-PCs are up to 300-fold more drug-resistant than PCs. Thus, clinical drug resistance in MM is linked to reversible, bidirectional phenotypic transition of myeloma-propagating cells. These novel biologic insights have important clinical implications in relation to assessment of minimal residual disease and development of alternative therapeutic strategies in MM.

Regulation of multiple myeloma survival and progression by CD1d.

Down-regulation of conventional human leukocyte antigen (HLA) class I and II molecules from the surface of tumor cells is an important mechanism for tumor immune evasion, survival, and progression. Whether CD1d, a nonconventional, glycolipid-presenting HLA class I-like molecule instructing the function of the immunoregulatory invariant NKT cells can affect tumor cell survival is not known. Here we show that CD1d is highly expressed in premalignant and early myeloma, but with disease progression its expression is reduced and eventually in advanced stages and myeloma cell lines is lost altogether, suggesting that CD1d impacts negatively on myeloma cell survival. Consistent with this, engagement of CD1d by anti-CD1d monoclonal antibodies (mAbs) induces cell death of myeloma cell lines with restored CD1d expression and primary myeloma cells. Cell death induced by monoclonal antibody engagement of CD1d is associated with overexpression of proapoptotic Bax and mitochondrial membrane potential loss but it is caspase-activation independent; in addition, it requires the cytoplasmic tail but not the Tyr residue critical for lysosomal sorting of CD1d. Finally, anti-CD1d cooperates with antimyeloma agents in the killing of myeloma cells. Thus, this work provides evidence linking a novel function of CD1d in the regulation of cell death with tumor survival and progression in humans.

Poly(ADP-ribose) polymerase family member 14 (PARP14) is a novel effector of the JNK2-dependent pro-survival signal in multiple myeloma

Regulation of cell survival is a key part of the pathogenesis of multiple myeloma (MM). Jun N-terminal kinase (JNK) signaling has been implicated in MM pathogenesis, but its function is unclear. To elucidate the role of JNK in MM, we evaluated the specific functions of the two major JNK proteins, JNK1 and JNK2. We show here that JNK2 is constitutively activated in a panel of MM cell lines and primary tumors. Using loss-of-function studies, we demonstrate that JNK2 is required for the survival of myeloma cells and constitutively suppresses JNK1-mediated apoptosis by affecting expression of poly(ADP-ribose) polymerase (PARP)14, a key regulator of B-cell survival. Strikingly, we found that PARP14 is highly expressed in myeloma plasma cells and associated with disease progression and poor survival. Overexpression of PARP14 completely rescued myeloma cells from apoptosis induced by JNK2 knockdown, indicating that PARP14 is critically involved in JNK2-dependent survival. Mechanistically, PARP14 was found to promote the survival of myeloma cells by binding and inhibiting JNK1. Moreover, inhibition of PARP14 enhances the sensitization of MM cells to anti-myeloma agents. Our findings reveal a novel regulatory pathway in myeloma cells through which JNK2 signals cell survival via PARP14, and identify PARP14 as a potential therapeutic target in myeloma.

Malignancies Confined to Disused Arteriovenous Fistulae in Renal Transplant Patients: An Important Differential Diagnosis

Background: Swelling in an arteriovenous fistula (AVF) is commonly caused by thrombosis, aneurysm and infection. However, due to the increased risk of malignancy after transplantation, this should also be considered. Patients: We discuss 4 patients with malignancy confined to an AVF after renal transplantation presenting in a 2-year period. Angiosarcoma was diagnosed in 3 patients and the other had post-transplant lymphoproliferative disorder (PTLD). Angiosarcoma behaves aggressively and 2 of our patients died within 6 months of diagnosis. There are 6 previous cases and 5 died within 16 months of diagnosis. PTLD at AVFs has not been documented previously. Conclusion: Malignancy at an AVF is a rare but important differential that can impact significantly on patient morbidity and mortality. Predilection for malignancy at an AVF is not understood. We review the literature and discuss possible aetiologies.

Overlapping dose responses of spermatogenic and extragonadal testosterone actions jeopardize the principle of hormonal male contraception

Testosterone (T), alone or in combination with progestin, provides a promising approach to hormonal male contraception. Its principle relies on enhanced negative feedback of exogenous T to suppress gonadotropins, thereby blocking the testicular T production needed for spermatogenesis, while simultaneously maintaining the extragonadal androgen actions, such as potency and libido, to avoid hypogonadism. A serious drawback of the treatment is that a significant proportion of men do not reach azoospermia or severe oligozoospermia, commensurate with contraceptive efficacy. We tested here, using hypogonadal luteinizing hormone/choriongonadotropin receptor (LHCGR) knockout (LHR–/–) mice, the basic principle of the T‐based male contraceptive method, that a specific T dose could maintain extragonadal androgen actions without simultaneously activating spermatogenesis. LHR–/– mice were treated with increasing T doses, and the responses of their spermatogenesis and extragonadal androgen actions (including gonadotropin suppression and sexual behavior) were assessed. Conspicuously, all dose responses to T were practically superimposable, and no dose of T could be defined that would maintain sexual function and suppress gonadotropins without simultaneously activating spermatogenesis. This finding, never addressed in clinical contraceptive trials, is not unexpected in light of the same androgen receptor mediating androgen actions in all organs. When extrapolated to humans, our findings may jeopardize the current approach to hormonal male contraception and call for more effective means of inhibiting intratesticular T production or action, to achieve consistent spermatogenic suppression.—Oduwole, O. O., Vydra, N., Wood, N. E. M., Samanta, L., Owen, L., Keevil, B., Donaldson, M., Naresh, K., Huhtaniemi, I. T. Overlapping dose responses of spermatogenic and extragonadal testosterone actions jeopardize the principle of hormonal male contraception. FASEB J. 28, 2566–2576 (2014). www.fasebj.org

No Evidence of XMRV or MuLV Sequences in Prostate Cancer, Diffuse Large B-Cell Lymphoma, or the UK Blood Donor Population

Xenotropic murine leukaemia virus-related virus (XMRV) is a recently described retrovirus which has been claimed to infect humans and cause associated pathology. Initially identified in the US in patients with prostate cancer and subsequently in patients with chronic fatigue syndrome, doubt now exists that XMRV is a human pathogen. We studied the prevalence of genetic sequences of XMRV and related MuLV sequences in human prostate cancer, from B cell lymphoma patients and from UK blood donors. Nucleic acid was extracted from fresh prostate tissue biopsies, formalin-fixed paraffin-embedded (FFPE) prostate tissue and FFPE B-cell lymphoma. The presence of XMRV-specific LTR or MuLV generic gag-like sequences was investigated by nested PCR. To control for mouse DNA contamination, a PCR that detected intracisternal A-type particle (IAP) sequences was included. In addition, DNA and RNA were extracted from whole blood taken from UK blood donors and screened for XMRV sequences by real-time PCR. XMRV or MuLV-like sequences were not amplified from tissue samples. Occasionally MuLV gag and XMRV-LTR sequences were amplified from Indian prostate cancer samples, but were always detected in conjunction with contaminating murine genomic DNA. We found no evidence of XMRV or MuLV infection in the UK blood donors.

Enteropathy-associated T cell lymphoma subtypes are characterized by loss of function of SETD2

Enteropathy-associated T cell lymphoma (EATL) is a lethal, and the most common, neoplastic complication of celiac disease. Here, we defined the genetic landscape of EATL through whole-exome sequencing of 69 EATL tumors. SETD2 was the most frequently silenced gene in EATL (32% of cases). The JAK-STAT pathway was the most frequently mutated pathway, with frequent mutations in STAT5B as well as JAK1, JAK3, STAT3, and SOCS1. We also identified mutations in KRAS, TP53, and TERT. Type I EATL and type II EATL (monomorphic epitheliotropic intestinal T cell lymphoma) had highly overlapping genetic alterations indicating shared mechanisms underlying their pathogenesis. We modeled the effects of SETD2 loss in vivo by developing a T cell–specific knockout mouse. These mice manifested an expansion of &ggr;&dgr; T cells, indicating novel roles for SETD2 in T cell development and lymphomagenesis. Our data render the most comprehensive genetic portrait yet of this uncommon but lethal disease and may inform future classification schemes.

Diagnostic criteria schemes for multicentric Castleman disease in 75 cases.

that also includes training for Ugandan physicians in Cleveland, Ohio In addition, CWRU has partnered with the UHI and the Joint Clinical Research Centre (a center in existence in Uganda for care and research in HIV/AIDS) to focus specifically on RHD through an innovative foundation-funded project. This program will use an existing network of HIV/ AIDS infrastructure to create communitybased RHD treatment centers of excellence. If successful, this program may serve as a model for leveraging HIV/AIDS resources for the treatment of noncommunicable diseases among both HIV-infected and HIV-uninfected patients in RLS. We are now at a crossroads. An opportunity exists to build upon the dramatic improvements in health care infrastructure that HIV/AIDS investment has brought over the past decade. To extend the benefits of the ART rollout to the treatment of non-AIDS comorbidities such as RHD will require a coordinated research effort and capital investment in health systems, particularly in human resources. Multilateral collaborations in medical specialties beyond infectious diseases that share the tripartite mission of research, education, and clinical care such as the one described in this report will be needed to move to the next level of HIV/AIDS treatment in sub-Saharan Africa and other RLS.

IgG4 positive mucosa associated lymphoid tissue lymphoma of the orbit - lesson of the month

IgG4-related disease is a multisystem autoimmune disorder that can involve pancreas, liver, biliary tract, lung, breast, kidney, retroperitoneum, lymph node, thyroid gland, salivary gland, ocular adnexa (especially the lacrimal gland and orbit, excluding the conjunctiva), and other organs. Patients present with organomegaly and high serum IgG4 levels. Lesions respond to steroids, but recurrences are frequent. Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is well known to be associated with infectious agents (such as H. Pylori, Borrelia burgdorferi, Chlamydia psittaci and Campylobacter jejuni) and with autoimmune diseases (such as Sj€ogren syndrome and Hashimoto thyroiditis). More recently, IgG4-positve MALT lymphomas have been described in ocular, dural, thyroid and cutaneous sites. The question whether IgG4-related disease might be a precursor lesion to MALT lymphoma needs to be answered as IgG4-related disease is also thought to have an autoimmune basis. We document a case of IgG4 positive MALT lymphoma of the orbit. A 69 year old man presented with continuing enlargement of his lacrimal glands for 4 years for which he underwent a left lacrimal gland biopsy in another hospital and was then referred to Imperial College Healthcare NHS Trust. He had no diplopia, xerophthalmia or xerostomia. He had noticed no other lumps, and was otherwise well. His past medical history included type 2 diabetes, mild asthma and ischaemic heart disease. On examination, there was obvious bilateral enlargement of lacrimal glands. There was no superficial lymphadenopathy. Chest was clear. Contrast enhanced MRI of the head showed bilateral enlargement of the lacrimal glands with extension of disease into the left subcutaneous tissues, bilateral extension into the orbital apices and involvement of superior and lateral recti (Figure 1). A CT scan revealed mildly enlarged lymph nodes in the left axilla and subtle right paravertebral soft tissue adjacent to T9 and small retroperitoneal lymph nodes. Serum immunoglobulins measured: IgA – 1.59 g/l (normal range: 0.8–4.0 g/l); IgG – 20.9 g/l (normal range: 5.3–16.5 g/l); and IgM – 0.22 g/l (normal range: 0.5–2.0 g/l). Furthermore, IgG subsets measured: IgG1 – 5.54 g/l (normal range: 3.2– 10.2 g/l); IgG2 – 3.07 g/l (normal range: 1.2–6.6 g/l); IgG3 – 0.45 g/l (normal range: 0.2–1.7 g/l); and IgG4 – 16.8 g/l (normal: <1.3 g/l). A bone marrow trephine biopsy showed no evidence of lymphoma. He was treated with Rituximab, Cyclophosphamide, Vincristine and Prednisolone. Biopsy showed fragments of fibroadipose tissue with a lobular lymphoid and plasma cell infiltrate. There were well formed germinal centres surrounded by mantle zones and expanded marginal zones. Intervening areas showed predominance of plasma cells with an accompanying centrocyte-like lymphoid cell infiltrate. There was significant fibrosis in these areas and vascularity was prominent (Figure 2). On immunohistochemistry, CD20, CD10 and BCL6 highlighted reactive germinal centres, and they were negative for BCL2. There were also CD20 positive B cells outside the follicles. These B cells were negative for CD5, CD10 and CD23. Plasma cells expressed MUM1 and IgG, and showed kappa light chain restriction. Plasma cells were negative for IgM and IgD. A significant proportion of plasma cells also expressed IgG4. IgG4+ cells amounted to >50 per high-power field in many areas, and in these areas, the IgG4/IgG ratio

Aggressive B-Cell Lymphomas

Aggressive B-cell lymphomas (ABLs) are a group of B-cell malignancies, that is, a relatively common form of cancer across the world. This issue on aggressive B-cell lymphomas compiles 12 exciting manuscripts, most of which are very meticulously performed reviews of the available current literature. Three areas of lymphoma pathology and biology that are leading to a greater understanding of relatively recently defined entities are discussed. These include anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (ALK+ LBCL), and the so-called grey zone lymphomas or lymphomas with intermediate features and the posttransplant lymphoproliferative disorders. ALK+ LBCL are characterised by gene rearrangement involving clathrin and ALK genes (t(2;17)(p23;q23)). Grey zone lymphomas include two unclassifiable B-cell lymphomas, one with features intermediate between diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma (cHL) and the second with features intermediate between DLBCL and Burkitt lymphoma (BL). The biology of common lymphomas is addressed in two manuscripts. M. Rossi et al. review the current literature on molecular subsets of DLBCL, the distinction between DLBCL and BL, and gene expression characteristics of the grey zone lymphomas. This paper is accompanied by M. Cacciatore et al.s manuscript that explores the importance of the microenvironment in lymphoma biology. Two of the manuscripts deal with those aspects of endemic BL pathogenesis that have hitherto not been explored in great depth. The paper by S. Mannucci et al. explore the possibility of Euphorbia tirucalli acting as a cofactor in BL. They show that, in lymphoblastoid cell lines, E. tirucalli can modulate the EBV latency genes, result in polysomy for chromosome 8, and cause upregulation of c-MYC. Furthermore, Dr. C. van den Bosch raises question about a possible role for RNA viruses in the pathogenesis of BL. Dr. I. Magrath reviews the evolution of BL treatment in Africa—from cyclophosphamide monotherapy to multiagent combination chemotherapy including central nervous system prophylaxis using combinations of cyclophosphamide, vincristine, prednisone, and methotrexate. He also highlights the benefits of collaboration between resource-rich and resource-poor settings. P. Vishnu and D. M. Aboulafia review how the treatment of HIV-associated lymphomas has evolved since the introduction of highly active antiretroviral therapy (HAART). The use of rituximab, in conjunction with multiagent chemotherapy, and where required high-dose chemotherapy (HDCT) and autologous stem cell rescue (ASCT) have all contributed to the success of treating HIV lymphomas. Treatment of ABL is further reviewed in two paper—one on ASCT in DLBCL and the other on novel therapies by K. Foon et al. To complete the issue, S. Donnou reviews the currently available murine models useful for studying lymphomagenesis, the lymphoma microenvironment, and the efficacy of new therapies. By compiling these paper, we hope to enrich our readers and researchers with respect to these particularly common, yet usually highly treatable aggressive B-cell malignancies. Kikkeri N. Naresh Ian Magrath Martine Raphael Lorenzo Leoncini