Recombinant human thrombopoietin improves platelet engraftment after autologous hematopoietic stem cell transplantation in patients with aggressive lymphoma.

BACKGROUND: To explore the efficiency and safety of recombinant human thrombopoietin (TPO) on the platelet engraftment after autologous stem cell transplantation (ASCT) in patients with aggressive lymphoma. PATIENTS AND METHODS: Forty patients were enrolled in a single-center, retrospective clinical trial from July 2019 with rhTPO administration when the platelet count ≤ 75 × 109/L after the reinfusion of stem cells. The hematopoietic reconstitution, platelet transfusion dependence, the cost and length of hospitalization, side effects and survival benefit were compared between the rhTPO group and the control group of 25 historic patients without rhTPO. RESULTS: The cumulative incidence of platelet engraftment in the rhTPO group was significantly higher since d+ 13 post-transplantation. But no difference of neutrophil engraftment was found. rhTPO was considered to influence the platelet engraftment independently by multivariate analysis. Subgroup analysis demonstrated that when the patients were older than 45 years old, male, at stage-IV as diagnosed and obtained PR after previous treatment, rhTPO was more recommended to facilitate platelet early engraftment after ASCT. Although rhTPO didn't relieve the dependency of platelet transfusion, patients had the shorter length of hospitalization. And better OS was shown in the rhTPO group. CONCLUSION: rhTPO improved platelet engraftment after ASCT with aggressive lymphoma, especially the ones older than 45 years old, male, at stage-IV as diagnosed and obtained PR after previous treatment. Although rhTPO didn't lessen platelet transfusion dependence, the length and medical cost of hospitalization were reduced when rhTPO was involved. rhTPO was efficacy and safety which could be recommended after ASCT.

CD19-CAR-DNT cells (RJMty19) in patients with relapsed or refractory large B-cell lymphoma: a phase 1, first-in-human study.

Background: Current approved chimeric antigen receptor (CAR) T-cell products are autologous cell therapies that are costly and poorly accessible to patients. We aimed to evaluate the safety and antitumor activity of a novel off-the-shelf anti-CD19 CAR-engineered allogeneic double-negative T cells (RJMty19) in patients with relapsed/refractory large B-cell lymphoma. We report the results from a first-in-human, open-label, single-dose, phase 1 study of allogeneic CD19-specific CAR double-negative T (CAR-DNT) cells. Methods: Eligibility criteria included the presence of measurable lesions, at least 2 lines of prior immunochemotherapy, and an ECOG score of 0-1. We evaluated four dose levels (DL) of RJMty19 in a 3 + 3 dose-escalation scheme: 1 × 106, 3 × 106, 9 × 106 and 2 × 107 CAR-DNT cells per kilogram of body weight. All patients received lymphodepleting chemotherapy with fludarabine and cyclophosphamide. The primary endpoints were dose-limiting toxicities (DLTs), incidence of adverse events (AEs), and clinically significant laboratory abnormalities. Secondary endpoints included evaluation of standard cellular pharmacokinetic parameters, immunogenicity, objective response rates (ORR), and disease control rate (DCR) per Lugano 2014 criteria. Findings: A total of 12 patients were enrolled between 22 July 2022 and 27 July 2023. Among these patients, 66% were classified as stage IV, 75% had an IPI score of 3 or higher, representing an intermediate risk or worse. The maximum tolerated dose was not reached because no DLT was observed. Four patient experienced grade 1 or 2 cytokine release syndrome and dizziness. The most common AEs were hematologic toxicities, including neutropenia (N = 12, 100%), leukopenia (N = 12, 100%), lymphopenia (N = 10, 83%), thrombocytopenia (N = 6, 50%), febrile neutropenia (N = 3, 25%), and anemia (N = 3, 25%). Seven subjects died till the cut-off date, five of them died of disease progression and two of them died of COVID 19. In all patients (N = 12), the ORR was 25% and CRR was 8.3%. DL1 and DL2 patients benefited less from the therapy (ORR: 17%, N = 1; DCR: 33%, N = 2). However, all DL3 patients achieved disease control (N = 3, 100%), and all DL4 patients achieved objective response (N = 3, 100%). Interpretation: Our results demonstrate that CD19-CAR-DNT cells appear to be well tolerated with promising antitumor activity in LBCL patients. Further study of this product with a larger sample size is warranted. This phase 1 study is registered on clinicaltrials.gov (NCT05453669). Funding: Wyze Biotech. Co., Ltd.

Outcomes and risk factors of SARS-CoV-2 omicron variant in B-cell lymphoma patients following CD19 targeted CAR-T therapy.

BACKGROUND: Little was known on infection and mortality rates, still less the risk factors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron variant in B-cell lymphoma patients following CD19 targeted chimeric antigen receptor T cell (CAR-T). AIMS: We performed a retrospective multicenter study and analyzed the details of relapsed/refractory (R/R) B-cell lymphoma patients who received CD19 targeted CAR-T heretofore in five cellular immunotherapy centers in China during the omicron wave. MATERIALS & METHODS: One hundred fifty-four patients were enrolled in this study. RESULTS: Among them, 52 patients (33.8%) were uninfected, 74 patients (48.1) had ambulatory mild disease (including nine patients of asymptomatic infection), 22 patients (14.3%) had moderate disease and six patients (3.9%) had severe disease when data collected up. Three patients with severe disease died from COVID-19, the death rate was 1.9% for all enrolled patients, and 2.9% for infected patients. We also found that patients over 60 years old or with diabetes mellitus (DM) tend to develop severe disease (p = 0.0057 and p = 0.0497, respectively). Patients had CAR-T infusion within 6 months also tend to have severe disease (p = 0.0011). In multivariate logistic regression model, CAR-T infusion within 6 months (relative risk (RR) 40.92; confidence interval (CI) 4.03-415.89; p = 0.002) were associated with significantly higher risk of severe disease. CONCLUSION: Through this study, we conclude that the outcome for B-cell lymphoma patients following CD19 targeted CAR-T therapy when facing omicron infection was improved, but aggressive precautionary measures were particularly crucial for patients with high risk factors.

Case Report: Radiation necrosis mimicking tumor progression in a patient with extranodal natural killer/T-cell lymphoma.

Radiation-induced cerebral necrosis, also known as radiation encephalopathy, is a debilitating condition that significantly impacts the quality of life for affected patients. Secondary central nervous system lymphoma (SCNSL) typically arises from highly aggressive mature B-cell lymphoma, but rarely from extranodal natural killer T-cell lymphoma (ENKTL). Treatment will be guided by differentiation between lymphoma progression from brain necrosis, and is particularly important for critically ill patients in an acute setting. However, differential diagnosis remains challenging because they share similar clinical manifestations and have no specific imaging features. We present the case of a 52-year-old man with ENKTL who suffered an emergency brain herniation secondary to massive radiation necrosis. The diagnosis established by brain biopsy ultimately led to appropriate treatment. The importance of the diagnostic biopsy is highlighted in this case for distinguishing between radiation necrosis and SCNSL.

Composite B-cell and T-cell lymphomas: clinical, pathological, and molecular features of three cases and literature review. / 三例复合性B细胞和Tç»†èƒžæ·‹å·´ç˜¤æ‚£è€ çš„ä¸´åºŠã€ç— ç†å’Œåˆ†å­å­¦ç‰¹å¾çš„åˆ†æžåŠæ–‡çŒ®å›žé¡¾.

Composite lymphoma (CL) involving B-cell lymphoma and T-cell lymphoma is extremely rare. Herein, we report three such cases using immunohistochemistry, flow cytometry, and the next-generation sequencing (NGS) to identify the pathological and molecular characteristics of CL. In the first case, the patient was admitted to hospital for generalized pruritic maculopapular rash over the whole body. An excisional biopsy of the skin lesions showed T-cell lymphoma. At the same time, the staging bone marrow (BM) biopsy revealed a diffuse large B-cell lymphoma (DLBCL). After R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) therapies, the patient produced a good response with substantial dissipation of the rashes and relief of skin. The other two patients were admitted to hospital due to lymphadenopathy and were diagnosed with DLBCL and follicular lymphoma (FL) after core needle biopsy of lymph nodes, BM biopsy, BM aspiration, and flow cytometry. Following R-CHOP and R-COP (rituximab, cyclophosphamide, vincristine, and prednisone) therapies, they achieved complete remission unconfirmed (CRu) and complete remission (CR). However, one or two years later, they suffered a relapse of lymphadenopathy. The shocking fact was that re-biopsy of lymphadenopathy revealed peripheral T-cell lymphoma (PTCL) and angioimmunoblastic T-cell lymphoma (AITL). NGS findings identified DNA methyltransferase 3a (DNMT3a), isocitrate dehydrogenase 2 (IDH2), Ras homolog gene family, member A (RHOA), splicing factor 3B subunit 1 (SF3B1), and tumor protein p53 (TP53) mutations. After immunochemotherapy, these patients achieved CRu and CR again. Nevertheless, they suffered a second relapse of T-cell lymphoma. Finally, they died due to progression of disease. We found that the occurrence of CL is associated with Epstein-Barr virus infection and DNMT3a, IDH2, and TP53 mutations, and the prognosis of the disease is closely related to the T-cell lymphoma components.

miR-433 Inhibits Glioblastoma Progression by Suppressing the PI3K/Akt Signaling Pathway Through Direct Targeting of ERBB4.

Glioblastoma multiforme (GBM) is a highly malignant brain tumor where new biomarkers and drug targets are much needed in the oncology clinic. miR-433 was identified as a tumor-suppressing miRNA in several different types of human cancer. However, the integrative biology of miR-433 in GBM is still largely unknown. By analyzing the expression profiles of miR-433 in 198 patients with glioma at The Cancer Genome Atlas, we found that the miR-433 expression was decreased in glioma whereas the low expression of miR-433 was significantly associated with shorter overall survival. We then conducted in vitro studies and demonstrated that increased expression of miR-433 suppressed the proliferation, migration, and invasion of LN229 and T98G cells, two representative glioma cell lines. Further, using in vivo mouse model, we found that upregulation of miR-433 inhibited the tumor growth of glioma cells. To situate the integrative biology understanding of the action of miR-433 in glioma, we identified ERBB4 as a gene targeted directly by miR-433 in LN229 and T98G cells. Overexpressed ERBB4 rescued the phenotype caused by overexpression of miR-433. Finally, we showed that miR-433 suppressed the PI3K/Akt pathway in glioma cells. In conclusion, our study demonstrated that miR-433 could potentially act as a tumor suppressor for GBM and may serve as a potential therapeutic target for GBM. Further integrative biology and clinical translational research are warranted to evaluate miR-433 in GBM.

Case report: Successful treatment of a patient with relapsed/refractory primary central nervous system lymphoma with thiotepa-based induction, autologous stem cell transplantation and maintenance.

Despite significant improvements in prognosis, a subset of patients with primary central nervous system lymphoma (PCNSL) remains at high risk for relapse. The treatment of relapsed and refractory (R/R) PCNSL remains a major clinical challenge. Herein, we present a 24-year-old patient with PCNSL who relapsed 4 years after initial diagnosis and subsequently became refractory to high-dose methotrexate (HD-MTX), temozolomide, whole brain radiation therapy (WBRT), ibrutinib, and lenalidomide. She received thiotepa with anti-programmed cell death protein 1 (PD-1) antibody and achieved partial remission and then underwent autologous stem cell transplantation (ASCT) with thiotepa-based conditioning. Post-transplant maintenance with thiotepa and anti-PD-1 at 3-month intervals resulted in a durable complete response (CR) in this case of R/R PCNSL. Our report highlights the important role of thiotepa in the treatment of patients with R/R PCNSL.

Adefovir dipivoxil inhibits APL progression through degradation of the oncoprotein PML-RARA.

Acute promyelocytic leukemia (APL) is highly aggressive and is frequently associated with disseminated intravascular coagulation and high early death rates. Although all-trans retinoic acid (RA) induces complete remission in a high proportion of patients with APL, there are limited treatments for APL patients with RA resistance. Here we report an atypical APL patient, with an APL-like disease that developed very slowly without anti-leukemia therapy for nearly 2 years. During that time, the patient only intermittently received anti-HBV drugs, i.e., the combination of adefovir dipivoxil (ADV) and entecavir (ETV), leading us to hypothesize that ADV and/or ETV could inhibit APL progression. Our results showed that anti-HBV drugs ADV and ETV both exhibited significantly inhibitory effects on APL cells, and ADV indicated a much greater cytotoxic effect than ETV on APL cells. We further found that ADV significantly promoted APL cell differentiation and apoptosis, thereby restraining the progression of APL. Most importantly, our study uncovered a novel mechanism of ADV prohibiting APL progression, which was mediated, at least in part, by inhibition of TRIB3 and degradation of the oncoprotein PML-RARA, therefore leading to APL cell differentiation and apoptosis. Taken together, our study demonstrated that ADV, an anti-HBV drug, had significantly inhibitory effects on APL, and provided a novel therapeutic strategy for APL patients with RA resistance.

Case Report: Primary Cardiac T-Cell Lymphoma With Complete Atrio-Ventricular Block Diagnosed by Endomyocardial Biopsy.

Primary cardiac lymphoma (PCL) is a rare disease, the definite diagnosis of which is sometimes difficult and mainly relies on endomyocardial biopsy. Primary cardiac T-cell lymphoma (PCTL) is an extremely rare sub-type of PCL. Here, we report on a 47-year-old female with PCTL who presented with fever, syncope, palpitations, and a third-degree atrioventricular block (AVB) on electrocardiogram. Chemotherapy was administered with two courses of methotrexate, cyclophosphamide, liposomal doxorubicin, vincristine, and dexamethasone (MTX-CHOP). As the tumor vanished, AVB changed from third degree to second degree and finally to sinus rhythm. In conclusion, endomyocardial biopsy is valuable in the diagnosis of primary cardiac lymphoma. It is worth noting that alterations in the electrocardiogram may indicate an attack on the heart by PCTL.

Clinical and laboratory characteristics of lymphoid neoplasms in serous effusions: a single centre experience in China.

BACKGROUND: Lymphoid neoplasms in serous effusions are uncommon, and the details of lymphoid neoplasms in serous effusions from China are still unclear. METHODS: Between January 2004 and December 2019, all patients with lymphoid neoplasms in pleural effusions, ascites, and pericardial effusions in our hospital, were reviewed. RESULTS: A total of 65 patients with lymphoid neoplasms were collected during this period. The top three neoplasms were diffuse large B-cell lymphoma (DLBCL) (n = 20, 30.7%), myeloma (n = 13, 20.0%), and T-lymphoblastic lymphoma (n = 7, 10.8%). In pleural effusions involving DLBCL, the cytomorphology of DLBCL cells was diverse; most pleural effusions were present during the tumor course (92.9%); bilateral pleural effusions were predominant (57.2%); and the median survival time was only 1.23 months after the effusion. In pleural effusions involving myeloma, 90.9% of cases (10/11) had a high ratio (> 1.0) of immature to mature plasma cells; paraprotein types of IgA (36.4%) and light chain λ (36.4%) were the most frequently found; bilateral pleural effusions were easily found (n = 10, 90.9%); and the median survival time was only 1.4 months after the effusion. CONCLUSION: In pleural effusions involving DLBCL, most of our patients with effusions are present during the tumor course, and bilateral pleural effusions are predominant. In pleural effusions involving myeloma, the paraprotein types of IgA and light chain λ are the most frequently found, and it has a high ratio of immature to mature plasma cells in pleural effusions.

Homoharringtonine Combined with the Heat Shock Protein 90 Inhibitor IPI504 in the Treatment of FLT3-ITD Acute Myeloid Leukemia.

As a heterogeneous group of clonal disorders, acute myeloid leukemia with internal tandem duplication of fms-like tyrosine kinase 3 (FLT3-ITD) mutation usually shows an inferior prognosis. In the present study, we found that homoharringtonine (HHT), a protein translation inhibitor of plant alkaloid in China, exhibited potent cytotoxic effect against FLT3-ITD (+) cell lines and primary leukemia cells, and a remarkable synergistic anti-leukemia action was demonstrated in vitro and in vivo in xenograft mouse models when co-treated with the heat shock protein 90 inhibitor IPI504. Mechanistically, HHT combined with IPI504 synergistically inhibited the growth of leukemia cells by inducing apoptosis and G1 phase arrest. This synergistic action resulted in a prominent reduction of total and phosphorylated FLT3 (p-FLT3) as well as inhibition of its downstream signaling molecules such as STAT5, AKT, ERK and 4E-BP1. Furthermore, co-treatment of HHT and IPI504 led to a synergistic or additive effect on 55.56%(10/18) of acute myeloid leukemia cases tested, including three relapsed/refractory patients. In conclusion, our findings indicate that the combination of HHT and HSP90 inhibitor provides an alternative way for the treatment of FLT3-ITD positive acute myeloid leukemia, especially for relapsed/refractory AML.

Secondary mixed phenotype acute leukemia following chemotherapy for diffuse large B-cell lymphoma: a case report and review of the literature.

Therapy-related mixed phenotype acute leukemia (MPAL) following non-Hodgkin's lymphoma (NHL) is extremely rare. We present here the case of an elderly man, diagnosed with diffuse large B-cell lymphoma (DLBCL) through a tonsil biopsy. After treatment with seven cycles of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) like regimen, the patient developed to MPAL (B/myeloid) with del(7)(q22), t(6;9)(p23;q34), DEK/NUP214 fusion, as well as EZH2 and TET2 mutations. The patient was successively treated with chemotherapy and allogenetic hematopoietic stem cell transplantation. Until recently he is still alive more than 23 months without relapse.

Chronic myelogenous leukemia following small lymphocytic lymphoma: a case report and review of literature.

Chronic myelogenous leukemia (CML) following non-Hodgkin's lymphoma (NHL) is extremely rare. Here we report a unique case of CML after small lymphocytic lymphoma (SLL). A 64-years-old Asian female was firstly diagnosed as SLL by biopsies of the retroperitoneal and the mesenteric root lymph nodes, with bone marrow (BM) involvement. BM chromosome showed no abnormalities, and the rearrangement of IgDH (DH1-6-JH) and IgK (Vk-Jk) gene were present. After treatment with three courses of fludarabine, cyclophosphamide, and rituximab (FCR) regimens, the patient achieved complete response. However, she progressed to CML 35 months later, with Philadelphia translocation and the major BCR/ABL fusion transcript (p210), and she has a good prognosis with imatinib. It is not clear whether BCR-ABL1 gene was present at the time of primary diagnosis for SLL, so we extracted genomic DNA from the patient's paraffin-embedded BM biopsies at the first diagnosis of SLL for comparison, but real-time quantitative PCR assay for BCR-ABL1 gene was negative. Taken together, there is a strong possibility that FCR therapy caused the BCR-ABL1 gene rearrangement, and then became CML in 35 months.

Peripheral T-cell lymphoma with hypercalcemic crisis as a primary symptom accompanied by polymyositis: A case report and review of the literature.

The present study reports the case of a 61-year-old male with polymyositis who presented with exacerbated weakness in the lower limbs and a recurrent fever that had persisted for one month. Positron emission tomography/computed tomography scans revealed multiple regions of elevated fluorodeoxyglucose metabolism in the lymph nodes, lungs, liver, spleen and bones. While symptoms of nonchalance and confusion were identified on admission, the patient's serum calcium level was high at 3.87 mmol/l, so a hypercalcemic crisis was confirmed. A biopsy of the right lingual lymph node revealed peripheral T-cell lymphoma, not otherwise specified. The serum calcium level was restored to within the normal range following emergency measures, such as saline rehydration, diuretics, calcitonin and glucocorticoids, and partial remission was achieved following two courses of chemotherapy. The study may improve our present understanding of the diagnosis and treatment of cancer-associated myositis (CAM) and malignancy-associated hypercalcemia.

Blue rubber bleb nevus syndrome: a case report and literature review.

Blue rubber bleb nevus syndrome (BRBNS) is a rare disease characterized by multiple venous malformations and hemangiomas in the skin and visceral organs. The lesions often involve the cutaneous and gastrointestinal systems. Other organs can also be involved, such as the central nervous system, liver, and muscles. The most common symptoms are gastrointestinal bleeding and secondary iron deficiency anemia. The syndrome may also present with severe complications such as rupture, intestinal torsion, and intussusception, and can even cause death. Cutaneous malformations are usually asymptomatic and do not require treatment. The treatment of gastrointestinal lesions is determined by the extent of intestinal involvement and severity of the disease. Most patients respond to supportive therapy, such as iron supplementation and blood transfusion. For more significant hemorrhages or severe complications, surgical resection, endoscopic sclerosis, and laser photocoagulation have been proposed. Here we present a case of BRBNS in a 45-year-old woman involving 16 sites including the scalp, eyelid, orbit, lip, tongue, face, back, upper and lower limbs, buttocks, root of neck, clavicle area, superior mediastinum, glottis, esophagus, colon, and anus, with secondary severe anemia. In addition, we summarize the epidemiology, clinical manifestations, diagnosis, differential diagnosis and therapies of this disease by analyzing all previously reported cases to enhance the awareness of this syndrome.

Clinicopathologic characteristics of prefibrotic-early primary myelofibrosis in Chinese patients.

The clinicopathologic features of patients with prefibrotic-early primary myelofibrosis (PEPMF) are still uncertain, and the characteristics of PEPMF in Asian patients are rarely reported. This study analyzed the clinicopathologic characteristics of 42 Chinese patients with PMF newly diagnosed according to the 2008 World Health Organization criteria. Some clinical and laboratory features of the patients differed significantly from those of the predominantly white patients in Western countries. Chinese patients with PEPMF were more often male (1.28:1) and younger, less likely to have higher median hemoglobin concentrations (126 g/L), less frequently had palpable spleens (35.7%), and had longer median times between prefibrotic-early and classical PEPMF (64 months). On bone marrow trephine sections, Chinese patients were more likely to have increased granulopoiesis (78.6%) and less frequently had balloon-like megakaryocytes (61.9%), giant and staghorn megakaryocytes (35.7%), or megakaryocytes with hyperchromatic and dysplastic nuclei (40.4%). In conclusion, some clinicopathologic characteristics of PEPMF in Chinese patients in China differ substantially from those seen in predominantly white patients in Western countries, and more clinicopathologic studies involving different ethnic populations and geographic regions of the world should help unfold the characteristics of this disease.

Clinical analysis and prognostic significance of hepatitis B virus infections for diffuse large B-cell lymphoma with or without rituximab therapy.

The aim of this study was to analyze the clinical features of hepatitis B surface antigen (HBsAg)-positive and negative diffuse large B-cell lymphomas (DLBCLs) and to compare the outcomes and serum hepatitis B virus (HBV)-DNA loads of patients treated with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) regimens with rituximab (RCHOP) or without. A total of 451 DLBCL patients, of which 90 were HBsAg-positive and 361 were HBsAg-negative, were retrospectively reviewed. We compared onset age, gender, Ann Arbor stage, international prognostic index (IPI), lactate dehydrogenase (LDH) and ß2-microglobulin (ß2-M) levels, as well as overall survival (OS) rates and HBV-DNA loads under CHOP or RCHOP regimens. The OS rate of the HBsAg-positive DLBCL patients was significantly lower than that of HBsAg-negative DLBCL patients and the HBsAg-positive DLBCL patients had an earlier median onset age. HBsAg-positive DLBCL patients had poorer OS rates compared with HBsAg-negative patients (62.2% HBsAg-positive vs. 76.2% HBsAg-negative, P=0.018). HBsAg-positive DLBCL patients with HBV-DNA loads >103 cps/ml during chemotherapy had significantly lower OS rates than those with lower HBV-DNA loads (48.4% HBV-DNA elevated vs. 71.2% HBV-DNA normal, P=0.037). HBsAg-positive DLBCL patients treated with RCHOP had a significantly higher OS rate (79.6%) compared with the 41 CHOP-treated patients (43.9%; P<0.001). HBsAg-positive DLBCL patients with an earlier median onset age and elevated HBV-DNA during chemotherapy had poorer prognoses. HBsAg and HBV-DNA during chemotherapy may be used as prognostic indicators for patients with DLBCL. Rituximab improves the outcome of HBsAg-positive DLBCL patients when administered in combination with anti-viral lamivudine.

[Effect of neferine combined with mdr-1shRNA on the expression of mdr-1/P-gp in K562/A02 cell line].

OBJECTIVE: To determine the effect of neferine (Nef) combined with mdr-1shRNA on the expression of mdr/P-gp in K562/A02 cell line. METHODS: MTT assay was used to observe the cell proliferation. The expression level of P-gp was determined by Western blot and the transcription of mdr-1 gene was detected by semi-quantitative RT-PCR. RESULTS: After K562/A02 cells were treated by Nef or mdr-1shRNA alone or both for 24 h, the proliferation of K562/A02 cells was significantly higher in the Nef combined with mdr-1shRNA treatment group than that of Nef or mdr-1shRNA alone group (P<0.01).The expression of mdr-1/P-gp in the Nef with mdr-1 shRNA group was significantly lower than that of Nef or mdr-1shRNA alone group. CONCLUSION: Nef enhances the inhibition of mdr-1shRNA expression vector on K562/A02 cell proliferation and on P-gp protein to effectively reverse multidrug resistance induced by mdr-1 gene encoding P-gp.

[Improvement of Phi bodies stain and its clinical significance].

The aim of this study was to improve the dyeing method of hydroperoxidase (HPO), to analyze the morphologic features of Phi bodies and to evaluate the clinical application of this method. 128 bone marrow or peripheral blood smears from patients with myeloid and lymphoid malignancies were stained by improved HPO staining. The Phi bodies were observed with detection rate of Phi bodies in different leukemias. 69 acute myeloid leukemia (AML) specimens were chosen randomly, the positive rate and the number of Phi bodies between the improved HPO and POX stain based on the same substrate of 3, 3'diaminobenzidine were compared. The results showed that the shape of bundle-like Phi bodies was variable, long or short. while the nubbly Phi bodies often presented oval and smooth. Club-like Phi bodies were found in M(3). The detection rates of bundle-like Phi bodies in AML M(1)-M(5) were 42.9% (6/14), 83.3% (15/18), 92.0% (23/25), 52.3% (11/21), 33.3% (5/15) respectively, and those of nubbly Phi bodies were 28.6% (4/14), 66.7% (12/18), 11.1% (3/25), 33.3% (7/21), 20.0% (3/15) respectively. The detection rate of bundle-like Phi bodies in M(3) was significantly higher than that in (M(1) + M(2)) or (M(4) + M(5)) groups. The detection rate of nubbly Phi bodies in (M(1) + M(2)) group was higher than that in M(3) group. In conclusion, after improvement of staining method, the HPO stain becomes simple, the detection rate of Phi bodies is higher than that by the previous method, the positive granules are more obvious, and the results become stable. This improved method plays an important role in differentiating AML from ALL, subtyping AML, and evaluating the therapeutic results.

[Reversal of multidrug resistance by MDR1 shRNA expression vector in human leukemia K562/A02 cells].

OBJECTIVE: To construct a short hairpin RNA (shRNA) eukaryotic expression vector specific to MDR1 gene in multidrug resistance (MDR) human leukemia cell line K562/A02 to observe its silencing effect on MDR1 and P-glycprotein (P-gp) expression. METHODS: The shRNA expression vector was constructed by gene recombination, then transfected into the cultured K562/A02 cells. The transcription of MDR1 gene was detected by semi-quantitative RT-PCR and the expression level of P-gp was determined by Western blot. 50% inhibition concentration (IC50) of ADM in K562/A02 cells was determined by MTT method. The intracellular doxorubicin (ADM) concentration was determined by HPLC. RESULTS: The introduction of pEGFP-C1/U6/MDR1-A or pEGFP-C1/U6/MDR1-B expression vector was shown to efficiently and specifically inhibit the expression of P-gp according to results of Western blot, with an inhibitory rate of 50.67%. Semi-quantitative RT-PCR showed that mRNA transcription of MDR1 gene was reduced by (48.2 +/- 2.5)%. On the contrast, the control plasmid did not exhibit inhibitory effect on the protein expression and mRNA transcription of MDR1. The relative efficiency of K562/A02 to ADM was 40.8% or 62.4%, respectively, and the intracellular accumulation of ADM increased after shRNA treatment. CONCLUSION: The shRNA expression vector targeting MDR1 gene showed dramatic inhibition on RNA transcription and protein expression. It could effectively restore the sensitivity of K562/A02 cells to conventional chemotherapeutic agents.