Targeting Adaptive IRE1α Signaling and PLK2 in Multiple Myeloma: Possible Anti-Tumor Mechanisms of KIRA8 and Nilotinib.

BACKGROUND: Inositol-requiring enzyme 1α (IRE1α), along with protein kinase R-like endoplasmic reticulum kinase (PERK), is a principal regulator of the unfolded protein response (UPR). Recently, the 'mono'-specific IRE1α inhibitor, kinase-inhibiting RNase attenuator 6 (KIRA6), demonstrated a promising effect against multiple myeloma (MM). Side-stepping the clinical translation, a detailed UPR phenotype in patients with MM and the mechanisms of how KIRA8 works in MM remains unclear. METHODS: We characterized UPR phenotypes in the bone marrow of patients with newly diagnosed MM. Then, in human MM cells we analyzed the possible anti-tumor mechanisms of KIRA8 and a Food and Drug Administration (FDA)-approved drug, nilotinib, which we recently identified as having a strong inhibitory effect against IRE1α activity. Finally, we performed an RNA-sequence analysis to detect key IRE1α-related molecules against MM. RESULTS: We illustrated the dominant induction of adaptive UPR markers under IRE1α over the PERK pathway in patients with MM. In human MM cells, KIRA8 decreased cell viability and induced apoptosis, along with the induction of C/EBP homologous protein (CHOP); its combination with bortezomib exhibited more anti-myeloma effects than KIRA8 alone. Nilotinib exerted a similar effect compared with KIRA8. RNA-sequencing identified Polo-like kinase 2 (PLK2) as a KIRA8-suppressed gene. Specifically, the IRE1α overexpression induced PLK2 expression, which was decreased by KIRA8. KIRA8 and PLK2 inhibition exerted anti-myeloma effects with apoptosis induction and the regulation of cell proliferation. Finally, PLK2 was pathologically confirmed to be highly expressed in patients with MM. CONCLUSION: Dominant activation of adaptive IRE1α was established in patients with MM. Both KIRA8 and nilotinib exhibited anti-myeloma effects, which were enhanced by bortezomib. Adaptive IRE1α signaling and PLK2 could be potential therapeutic targets and biomarkers in MM.

[Cytomegalovirus meningoencephalitis in a diffuse large B-cell lymphoma patient undergoing salvage chemotherapy].

A 63-year-old woman was admitted to our hospital to receive a fourth course of modified rituximab-ESHAP chemotherapy for relapsed primary breast diffuse large B-cell lymphoma. She developed hemophagocytic lymphohistiocytosis (HLH) 20 days after admission. Polymerase chain reaction (PCR) detected cytomegalovirus (CMV) DNA in her peripheral blood; therefore, she was diagnosed with CMV-associated HLH and consequently treated with foscarnet (FCN). Her general condition and pancytopenia soon improved, and the antiviral drug was stopped for 1 week. However, she suddenly became disoriented 10 days later, and this condition rapidly worsened. Cerebrospinal fluid (CSF) examination revealed an elevated white blood cell count with lymphocytic predominance and a high CMV DNA load, prompting a final diagnosis of CMV meningoencephalitis. We began intravenous combination therapy with FCN and ganciclovir (GCV), and her conscious state gradually improved. CMV DNA sequencing did not reveal drug resistance associated with mutations, and intravenous GCV was stopped for 1 week. FCN treatment was then continued until CMV DNA was no longer detected in her CSF samples via PCR. CMV meningoencephalitis is a rare neurological infection complicated with hematological malignancy in non-transplant patients and can be serious and life-threatening with a high mortality rate. This infection requires a differential diagnosis of consciousness impairment that develops in a patient with lymphoid malignancy during chemotherapy.

[Refractory ascites developing in late-phase of cord blood transplantation improving with CART].

We managed a patient with acute myeloid leukemia (AML) who showed refractory ascites that developed in late-phase cord blood transplantation (CBT). The ascites obverted 5 months after CBT. The liver was atrophic, and serum hyaluronic acid was elevated at the onset, suggesting fibrotic changes in the liver. The ascites were transiently improved by cell-free and concentrated ascites reinfusion therapy (CART) and corticosteroid administration; however, the patient died from anasarca and recurrent AML 378 d after CBT. The etiology of the ascites is not well understood; therefore, additional studies on similar patients should be explored for proper management.

[Successful cord blood transplantation in a patient with adult-onset common variable immunodeficiency].

Common variable immunodeficiency (CVID) is the most frequently diagnosed congenital immunodeficiency and is characterized by dysfunctional antibody production. It often occurs at the age of ≥10 years. Here we reported a case of a 46-year-old man confirmed with adult-onset CVID. He was effectively treated with cord blood transplant (CBT). The patient was observed with repeated upper respiratory infection a few years back and was referred to our department owing to a marked decrease in neutrophil counts and progression of anemia. Laboratory tests confirmed hypogammaglobulinemia, but no autoantibodies were detected. Bone marrow aspiration showed a hypocellular marrow with predominantly mature lymphocytes. T-cell receptor excision circle assay revealed a reduction in T-cell neogenesis. Further, multicolor flow cytometry analysis revealed a low differentiation of B cells; subsequently, CVID was confirmed in the patient. The patient had a severe clinical course and therefore, received CBT for the treatment. After the transplantation, the hematopoiesis was restored and the serum immunoglobulin levels returned to normal. The patient exhibited a favorable clinical course. Nevertheless, there is no precise definition to establish the disease concept of CVID. Also, most of the potential cases are predominantly reported in adults. Therefore, further data on cases with CVID should be accumulated to establish the diagnostic criteria as well as treatment modalities.

Endovascular Mechanical Thrombectomy for Basilar Artery Occlusion Caused by Thrombosis as an Initial Manifestation of Acute Myelogenous Leukemia: A Case Report.

We report a rare case of a basilar artery occlusion (BAO) caused by thrombosis as an initial magnification of acute myelogenous leukemia (AML) and performed mechanical thrombectomy (MT) to treat it. A 67-year-old female presented left hemiparalysis of her arm and right-sided blindness. Magnetic resonance imaging (MRI) and magnetic resonance angiography revealed acute infarction in the left occipital and anterior lobes of the cerebellum and incomplete BAO. Her blood test showed hyperleukocytosis with precursor cells and high levels of C-reactive protein, and we diagnosed AML and disseminated intravascular coagulation (DIC). We decided to treat conservatively with rapid rehydration and heparin, but three hours after admission, she suddenly lost consciousness. We performed acute MT with a direct aspiration first-pass technique (ADAPT). A white elastic embolus was aspirated, and DSA showed successful recanalization of the basilar artery. The next day, MRI revealed acute infarction in the midbrain and bilateral thalamus. The patient remained unconscious after MT and so chemotherapy to treat the acute leukemia could not be performed. The patient died of the primary disease 14 days after BAO. Thrombosis in association with AML is very rare disease and could occur in arterial vessels because of hypercoagulation, and this tendency may not respond to anticoagulation therapy. Although ADAPT might be performed safety without complications even in cases of DIC, indications for treatment with MT should be carefully considered in patients in whom hemorrhage is a possibility.

Successful Intrathecal Chemotherapy Combined with Radiotherapy Followed by Pomalidomide and Low-Dose Dexamethasone Maintenance Therapy for a Primary Plasma Cell Leukemia Patient.

Primary plasma cell leukemia (PPCL) is a rare aggressive variant of plasma cell disorder and frequently presents with extramedullary disease. Central nervous system (CNS) involvement with PPCL has an extremely poor prognosis. We describe a 46-year-old man with PPCL treated with a combination of lenalidomide, bortezomib, and dexamethasone as induction therapy following upfront allogeneic stem cell transplantation (allo-SCT). Despite achieving a very good partial response, the patient suffered from an isolated CNS relapse 12 months after allo-SCT. He was immediately started on concurrent intrathecal chemotherapy (IT) and cranial irradiation (RT). Subsequently, pomalidomide and low-dose dexamethasone (Pd) were given as maintenance therapy. He has been without CNS recurrence for more than 18 months. Our case suggests that concurrent IT and RT followed by Pd maintenance therapy may be an effective option to control CNS relapse of PPCL after allo-SCT.

An Epstein-Barr virus susceptible immature T-cell line, WILL4, established from a patient with T-lymphoblastic lymphoma bearing CD21 and a clonal EBV genome.

We managed a patient with an Epstein-Barr virus-associated T-cell lymphoblastic lymphoma. Mediastinal tumor cells at initial admission were positive for CD4, CD8, and TdT. Interestingly, a lymph node at necropsy was compatible for a CD4-positive peripheral T-cell lymphoma without CD8 and TdT expression, suggesting a different phenotype from the mediastinal tumor. Tumor cells in pleural effusion continued to proliferate in in vitro and were designated as WILL4. WILL4 cells were positive for CD3, CD4, CD8, CD21, T-cell receptor (TcR) αß, and TdT, indicating a similar phenotype to thymocytes. Southern blot analyses showed that the pleural tumor and WILL4 cells shared a TcR gene rearrangement, and that both contained a clonal EBV genome in an episomal form. RT-PCR showed that EBNA1 and LMP1 were expressed in the fresh tumor and WILL4 cells. Southern blot analyses revealed that WILL4 cells were susceptible to EBV infection in vitro using B95-8 supernatant. Anti-CD21 antibody inhibited in vitro infection of EBV, suggesting that CD21 plays a role in EBV infection into WILL4 cells. In vitro infection of EBV did not affect latent gene expression in WILL4 cells. WILL4 is a useful tool for analyzing the roles of EBV in onocogenesis in immature T-lymphoid malignancies.