[Venetoclax with low-dose cytarabine for patients with untreated acute myeloid leukemia ineligible for intensive chemotherapy: results from the Chinese cohort of a phase three randomized placebo-controlled trial].

Objective: To investigate the safety and efficacy of venetoclax with low-dose cytarabine (LDAC) in Chinese patients with acute myeloid leukemia (AML) who are unable to tolerate intensive induction chemotherapy. Methods: Adults ≥ 18 years with newly diagnosed AML who were ineligible for intensive chemotherapy were enrolled in this international, randomized, double-blind, placebo-controlled trial. Globally, patients (n=211) were randomized 2∶1 to either venetoclax with LDAC or placebo with LDAC in 28-d cycles, with LDAC on days 1-10. The primary endpoint was OS; the secondary endpoints included response rates, event-free survival, and adverse events. Results: A total of 15 Chinese patients were enrolled (venetoclax arm, n=9; placebo arm, n=6) . The median age was 72 years (range, 61-86) . For the primary analysis, the venetoclax arm provided a 38% reduction in death risk compared with the placebo[hazard ratio (HR) , 0.62 (95%CI 0.12-3.07) ]. An unplanned analysis with an additional 6 months of follow-up demonstrated a median OS of 9.0 months for venetoclax compared with 4.1 months for placebo. The complete remission (CR) rates with CR with incomplete blood count recovery (CRi) were 3/9 (33%) and 0/6 (0%) , respectively. The most common non-hematologic adverse effects (venetoclax vs placebo) were hypokalemia[5/9 (56%) vs 4/6 (67%) ], vomiting[4/9 (44%) vs 3/6 (50%) ], constipation[2/9 (22%) vs 4/6 (67%) ], and hypoalbuminemia[1/9 (11%) vs 4/6 (67%) ]. Conclusion: Venetoclax with LDAC demonstrated meaningful efficacy and a manageable safety profile in Chinese patients consistent with the observations from the global VIALE-C population, making it an important treatment option for patients with newly diagnosed AML who are otherwise ineligible for intensive chemotherapy.

Molecular patterns of response and treatment failure after frontline venetoclax combinations in older patients with AML.

The BCL-2 inhibitor venetoclax combined with hypomethylating agents or low-dose cytarabine represents an important new therapy for older or unfit patients with acute myeloid leukemia (AML). We analyzed 81 patients receiving these venetoclax-based combinations to identify molecular correlates of durable remission, response followed by relapse (adaptive resistance), or refractory disease (primary resistance). High response rates and durable remissions were typically associated with NPM1 or IDH2 mutations, with prolonged molecular remissions prevalent for NPM1 mutations. Primary and adaptive resistance to venetoclax-based combinations was most commonly characterized by acquisition or enrichment of clones activating signaling pathways such as FLT3 or RAS or biallelically perturbing TP53. Single-cell studies highlighted the polyclonal nature of intratumoral resistance mechanisms in some cases. Among cases that were primary refractory, we identified heterogeneous and sometimes divergent interval changes in leukemic clones within a single cycle of therapy, highlighting the dynamic and rapid occurrence of therapeutic selection in AML. In functional studies, FLT3 internal tandem duplication gain or TP53 loss conferred cross-resistance to both venetoclax and cytotoxic-based therapies. Collectively, we highlight molecular determinants of outcome with clinical relevance to patients with AML receiving venetoclax-based combination therapies.

Enhancing venetoclax activity in acute myeloid leukemia by co-targeting MCL1.

Targeted therapies are frequently combined with standard cytotoxic drugs to enhance clinical response. Targeting the B-cell lymphoma 2 (BCL-2) family of proteins is an attractive option to combat chemoresistance in leukemia. Preclinical and clinical studies indicate modest single-agent activity with selective BCL-2 inhibitors (for example, venetoclax). We show that venetoclax synergizes with cytarabine and idarubicin to increase antileukemic efficacy in a TP53-dependent manner. Although TP53 deficiency impaired sensitivity to combined venetoclax and chemotherapy, higher-dose idarubicin was able to suppress MCL1 and induce cell death independently of TP53. Consistent with an MCL1-specific effect, cell death from high-dose idarubicin was dependent on pro-apoptotic Bak. Combining higher-dose idarubicin with venetoclax was able to partially overcome resistance in Bak-deficient cells. Using inducible vectors and venetoclax to differentially target anti-apoptotic BCL-2 family members, BCL-2 and MCL1 emerged as critical and complementary proteins regulating cell survival in acute myeloid leukemia. Dual targeting of BCL-2 and MCL1, but not either alone, prolonged survival of leukemia-bearing mice. In conclusion, our findings support the further investigation of venetoclax in combination with standard chemotherapy, including intensified doses of idarubicin. Venetoclax should also be investigated in combination with direct inhibitors of MCL1 as a chemotherapy-free approach in the future.

Enhanced differentiation of human adipose tissue-derived stromal cells into insulin-producing cells with glucagon-like peptide-1.

Type 1 diabetes mellitus (T1DM) is mainly caused by reduction of the endogenous insulin secretion due to autoimmune destruction of pancreatic ß cells, and a promising therapeutic approach for T1DM is pancreas and islet cell replacement. The major obstacle is the limited source of insulin-producing cells. Here, we report an efficient approach to induce human adipose-derived stromal cells (hADSCs) to differentiate into insulin-producing cells, with glucagon-like peptide-1 (GLP-1). hADSCs were successfully isolated from the adipose tissue, with adipogenic and osteogenic differentiation potency. Islet-like cell clusters formed in the culture, which was enhanced with the treatment of GLP-1. Reverse transcription polymerase chain reaction analysis showed the expression of the pancreas-related genes in the differentiated cells, such as pdx-1, ngn3, insulin, glucagon, somatostatin, glucokinase n and glut2. Immunocytochemical analysis showed that the induced cells co-expressed insulin, C-peptide and PDX-1. The GLP-1 receptor was present in the differentiated cells. In addition, flow cytometry analysis and ELISA showed that, in the presence of GLP-1, the percentage of insulin-producing cells was increased from 5.9% to 28.0% and the release of insulin increased from 9.53±0.7 pmol/106 cells to 15.86±1.3 pmol/106 cells. Insulin was released in response to glucose stimulation in a manner comparable to that of adult human islets. These results indicated that hADSCs isolated from adipose tissues can be induced to differentiate into insulin-producing cells, which is further enhanced with the treatment of GLP-1. These findings confirm that the differentiation of hADSCs to insulin-producing cells is indeed possible and indicate that the differentiated insulin-producing cells can be used as a potential source for transplantation into patients with T1DM.

In vitro and in vivo antitumor activity of Macrothelypteris torresiana and its acute/subacute oral toxicity.

The aim of this study was to evaluate the antitumor potential of Macrothelypteris torresiana by studying in vitro antitumor activity of the protoapigenone, as well as in vivo antitumor activity and acute/subacute oral toxicity of the total flavonoid fraction from the roots of M. torresiana. Considering that the protoapigenone is a main constituent of the total flavonoid fraction and it might play a key role in the antitumor activity of M. torresiana, the MTT assay was used to investigate the in vitro antitumor activity of the protoapigenone. Our study revealed that the protoapigenone of M. torresiana showed significant antitumor activity towards Hep G2, Tca-8113, MCF-7, M5 and K562 with IC(50) values of 2.3, 0.6, 0.8, 0.3 and 0.9 µg/ml, respectively. The antitumor potential of the total flavonoid fraction was evaluated using preparations 1, 2 and 3, which were prepared by total flavonoid fraction directly diluted with sterile saline, dissolved using sodium carboxymethyl cellulose (CMC-Na) and included by hydroxypropyl-ß-cyclodextrin, respectively. These were investigated in vivo using mouse sarcoma S-180 in BALB/c mice after completing tumor inoculation for 24h. Pronounced antitumor activity was observed in the treated groups for preparations 2 and 3, and the high and medium doses in particular showed very high inhibition ratio of tumor growth (>50%). No significant difference was observed when compared to the positive control group (5-fluorouracil). The acute/subacute oral toxicity test was performed, and the results of acute oral toxicity showed that the LD(50) values of preparations 2 and 3 were 2.76 and 0.87 g/kg body wt., respectively. According to the results of the subacute oral toxicity study, the total flavonoid fraction had low toxicity. The overall results of this study suggest that the total flavonoid fraction from the roots of M. torresiana shows significant antitumor activity and represents a potential source of medicine for the treatment of cancer.