Induction of apoptosis in hematological cancer cells by dorsomorphin correlates with BAD upregulation

AMPK inhibition sensitizes acute leukemia cells to BH3 mimetic-induced cell death

BH3 mimetics, including the BCL2/BCLXL/BCLw inhibitor navitoclax and MCL1 inhibitors S64315 and tapotoclax, have undergone clinical testing for a variety of neoplasms. Because of toxicities, including thrombocytopenia after BCLXL inhibition as well as hematopoietic, hepatic and possible cardiac toxicities after MCL1 inhibition, there is substantial interest in finding agents that can safely sensitize neoplastic cells to these BH3 mimetics. Building on the observation that BH3 mimetic monotherapy induces AMP kinase (AMPK) activation in multiple acute leukemia cell lines, we report that the AMPK inhibitors (AMPKis) dorsomorphin and BAY-3827 sensitize these cells to navitoclax or MCL1 inhibitors. Cell fractionation and phosphoproteomic analyses suggest that sensitization by dorsomorphin involves dephosphorylation of the proapoptotic BCL2 family member BAD at Ser75 and Ser99, leading BAD to translocate to mitochondria and inhibit BCLXL. Consistent with these results, BAD knockout or mutation to BAD S75E/S99E abolishes the sensitizing effects of dorsomorphin. Conversely, dorsomorphin synergizes with navitoclax or the MCL1 inhibitor S63845 to induce cell death in primary acute leukemia samples ex vivo and increases the antitumor effects of navitoclax or S63845 in several xenograft models in vivo with little or no increase in toxicity in normal tissues. These results suggest that AMPK inhibition can sensitize acute leukemia to multiple BH3 mimetics, potentially allowing administration of lower doses while inducing similar antineoplastic effects.

Drug repurposing based on differentially expressed genes suggests drug combinations with possible synergistic effects in treatment of lung adenocarcinoma

Lung adenocarcinoma is one of the leading causes of cancer-related mortality globally. Various treatment approaches and drugs had little influence on overall survival; thus, new drugs and treatment strategies are needed. Drug repositioning (repurposing) seems a favorable approach considering that developing new drugs needs much more time and costs. We performed a meta-analysis on 6 microarray datasets to obtain the main genes with significantly altered expression in lung adenocarcinoma. Following that, we found major gene clusters and hub genes. We assessed their enrichment in biological pathways to get insight into the underlying biological process involved in lung adenocarcinoma pathogenesis. The L1000 database was explored for drug perturbations that might reverse the expression of differentially expressed genes in lung adenocarcinoma. We evaluated the potential drug combinations that interact the most with hub genes and hence have the most potential to reverse the disease process. A total of 2148 differentially expressed genes were identified. Six main gene clusters and 27 significant hub genes mainly involved in cell cycle regulation have been identified. By assessing the interaction between 3 drugs and hub genes and information gained from previous clinical investigations, we suggested the three possible repurposed drug combinations, Vorinostat - Dorsomorphin, PP-110 - Dorsomorphin, and Puromycin - Vorinostat with a high chance of success in clinical trials.

Therapeutic advancements in targeting BCL-2 family proteins by epigenetic regulators, natural, and synthetic agents in cancer

Cancer is amongst the deadliest and most disruptive disorders, having a much higher death rate than other diseases worldwide. Human cancer rates continue to rise, thereby posing the most significant concerns for medical health professionals. In the last two decades, researchers have gone past several milestones in tackling cancer while gaining insight into the role of apoptosis in cancer or targeting various biomarker tools for prognosis and diagnosis. Apoptosis which is still a topic full of complexities, can be controlled considerably by B-cell lymphoma 2 (BCL-2) and its family members. Therefore, targeting proteins of this family to prevent tumorigenesis, is essential to focus on the pharmacological features of the anti-apoptotic and pro-apoptotic members, which will help to develop and manage this disorder. This review deals with the advancements of various epigenetic regulators to target BCL-2 family proteins, including the mechanism of several microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Similarly, a rise in natural and synthetic molecules' research over the last two decades has allowed us to acquire insights into understanding and managing the transcriptional alterations that have led to apoptosis and treating various neoplastic diseases. Furthermore, several inhibitors targeting anti-apoptotic proteins and inducers or activators targeting pro-apoptotic proteins in preclinical and clinical stages have been summarized. Overall, agonistic and antagonistic mechanisms of BCL-2 family proteins conciliated by epigenetic regulators, natural and synthetic agents have proven to be an excellent choice in developing cancer therapeutics.

Targeting USP9X-AMPK Axis in ARID1A-Deficient Hepatocellular Carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is a highly heterogeneous solid tumor with high morbidity and mortality. AT-rich interaction domain 1A (ARID1A) accounts for up to 10% of mutations in liver cancer, however, its role in HCC remains controversial, and no targeted therapy has been established.

METHODS

The expression of ARID1A in clinical samples was examined by Western blot and immunohistochemical staining. ARID1A was knocked out by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) in HCC cell lines, and the effects of glucose deprivation on cell viability, proliferation, and apoptosis were measured. Mass spectrometry analysis was used to find ARID1A-interacting proteins, and the result was verified by co-immunoprecipitation and Glutathione S Transferase (GST) pull-down. The regulation of ARID1A target gene USP9X was investigated by chromatin immunoprecipitation, Glutathione S Transferase (GST) pull-down, luciferase reporter assay, and so forth. Finally, drug treatments were performed to explore the therapeutic potential of the agents targeting ARID1A-deficient HCC in vitro and in vivo.

RESULTS

Our study has shown that ARID1A loss protected cells from glucose deprivation-induced cell death. A mechanism study disclosed that AIRD1A recruited histone deacetylase 1 via its C-terminal region DUF3518 to the promoter of USP9X, resulting in down-regulation of USP9X and its target protein kinase AMP-activated catalytic subunit α2 (PRKAA2). ARID1A knockout and a 1989∗ truncation mutant in HCC abolished this effect, increased the levels of H3K9 and H3K27 acetylation at the USP9X promoter, and up-regulated the expression of USP9X and protein kinase AMP-activated catalytic subunit α2 (PRKAA2), which mediated the adaptation of tumor cells to glucose starvation. Compound C dramatically inhibited the growth of ARID1A-deficient tumors and prolongs the survival of tumor-bearing mice.

CONCLUSIONS

HCC patients with ARID1A mutation may benefit from synthetic lethal therapy targeting the ubiquitin-specific peptidase 9 X-linked (USP9X)-adenosine 5'-monophosphate-activated protein kinase (AMPK) axis.

Emerging role of BAD and DAD1 as potential targets and biomarkers in cancer

As key regulators of apoptosis, BAD and defender against apoptotic cell death 1 (DAD1) are associated with cancer initiation and progression. Multiple studies have demonstrated that BAD and DAD1 serve critical roles in several types of cancer and perform various functions, such as participating in cellular apoptosis, invasion and chemosensitivity, as well as their role in diagnostic/prognostic judgement, etc. Investigating the detailed mechanisms of the cancerous effects of the two proteins will contribute to enriching the options for targeted therapy, and may improve clinical treatment of cancer. The present review summarizes research advances regarding the associations of BAD and DAD1 with cancer, and a hypothesis on the feasible relationship and interaction mechanism between the two proteins is proposed. Furthermore, the present review highlights the potential of the two proteins as therapeutic targets and valuable diagnostic and prognostic biomarkers.