High-throughput screening identifies artesunate as selective inhibitor of cancer stemness: Involvement of mitochondrial metabolism.

Cancer stem cells (CSCs) have robust systems to maintain cancer stemness and drug resistance. Thus, targeting such robust systems instead of focusing on individual signaling pathways should be the approach allowing the identification of selective CSC inhibitors. Here, we used the alkaline phosphatase (ALP) assay to identify inhibitors for cancer stemness in induced cancer stem-like (iCSCL) cells. We screened several compounds from natural product chemical library and evaluated hit compounds for their efficacy on cancer stemness in iCSCL tumorspheres. We identified artesunate, an antimalarial drug, as a selective inhibitor of cancer stemness. Artesunate induced mitochondrial dysfunction that selectively inhibited cancer stemness of iCSCL cells, indicating an essential role of mitochondrial metabolism in cancer stemness.

Discovery of novel selenium derivatives as Pin1 inhibitors by high-throughput screening.

Peptidyl prolyl cis/trans isomerization by Pin1 regulates various oncogenic signals during cancer progression, and its inhibition through multiple approaches has established Pin1 as a therapeutic target. However, lack of simplified screening systems has limited the discovery of potent Pin1 inhibitors. We utilized phosphorylation-dependent binding of Pin1 to its specific substrate to develop a screening system for Pin1 inhibitors. Using this system, we screened a chemical library, and identified a novel selenium derivative as Pin1 inhibitor. Based on structure-activity guided chemical synthesis, we developed more potent Pin1 inhibitors that inhibited cancer cell proliferation.

Autocrine and paracrine modulation of microRNA-155 expression by globular adiponectin in RAW 264.7 macrophages: involvement of MAPK/NF-κB pathway.

Adiponectin, a hormone produced from adipose tissue, regulates various biological responses, including inflammation and many metabolic processes. MicroRNAs control expression of diverse target genes and various physiological responses. Many of these responses are commonly regulated by adiponectin. However, effects of adiponectin on microRNAs regulation are largely unknown. Herein we demonstrated that globular adiponectin induces increase in miR-155 expression, which plays an important role in inflammatory response, in RAW 264.7 macrophages. We further showed that this effect was modulated by and MAPK/NF-κB dependent mechanisms. These results suggest that miR-155 would be a novel promising target mediating adiponectin-induced various biological responses.

Pituitary macroadenoma with panhypopituitarism masquerading as schizophrenia: a diagnostic dilemma managed conservatively.

Introduction and importance: Secretory pituitary macroadenoma also known as prolactinoma are benign neoplasm comprising very minimal cases of intracranial masses. Among the various presentation suggestive of panhypopituitarism, psychosis, and features of schizophrenia is very rarely seen. In the majority of cases, neurosurgical intervention for the excision of tumor is considered a standard treatment modality but conservative management with dopamine agonist and steroids have also been shown to provide an optimal level of care also improving the quality of level of patient. Case presentation: A 42-year-old Asian male presented with a history of talking to self, delusion of persecution, over talkativeness, hallucination, increased suspiciousness, and history of lost and found in the streets where he was working as a migrant worker. The patient was initially managed in line of schizophrenia with the antipsychotics drug of choice. On further assessment there was no improvement of psychiatric symptoms but they further deteriorated with additional neuropsychiatric symptoms; hence, MRI brain was carried out. Following which, the diagnosis of pituitary macroadenoma was confirmed and further more hormonal analysis was done, which showed findings suggestive of panhypopituitarism. The patient was then managed conservatively with dopamine agonist and steroids, which showed rapid improvement of psychiatric symptoms with a massive reduction in the size of the pituitary macroadenoma. Clinical discussion: With the incidence of 100 per million cases pituitary adenomas are considered locally invading with the characteristic compression of the surrounding structure, presenting as visual hallucinations, olfactory hallucinations, episodes of losing time, apathy, and features suggestive of adrenal insufficiency, hypogonadotrophic hypogonadism, and symptoms secondary to hormonal imbalance such as hypothyroidism. Psychiatric symptomatic presentations are considered a very rare presentation in cases of pituitary macroadenoma. Also, psychiatric features and symptoms of psychosis are associated with prolcatinomas through idiopathic mechanism and the basic casualty has not been established. Surgical intervention such as trans-sphenoidal resection of the mass can be undertaken in case where mass effects is present but long-term remission and prognosis is found not to be fruitful. Conservative treatment with dopamine agonist such as cabergoline and steroids also plays a meaningful role in abrupt management in such cases. Conclusion: Pituitary macroadenoma presenting as a patient of schizophrenia is noted very rarely in medical literature; hence, investigations in view of neurosurgical diagnosis in cases presenting as psychosis should be considered for ideal holistic management. Conservative management can also be a breakthrough treatment modality in complete recovery of pituitary macroadenoma.

Nicotinamide phosphoribosyltransferase inhibitors selectively induce apoptosis of AML stem cells by disrupting lipid homeostasis.

Current treatments for acute myeloid leukemia (AML) are often ineffective in eliminating leukemic stem cells (LSCs), which perpetuate the disease. Here, we performed a metabolic drug screen to identify LSC-specific vulnerabilities and found that nicotinamide phosphoribosyltransferase (NAMPT) inhibitors selectively killed LSCs, while sparing normal hematopoietic stem and progenitor cells. Treatment with KPT-9274, a NAMPT inhibitor, suppressed the conversion of saturated fatty acids to monounsaturated fatty acids, a reaction catalyzed by the stearoyl-CoA desaturase (SCD) enzyme, resulting in apoptosis of AML cells. Transcriptomic analysis of LSCs treated with KPT-9274 revealed an upregulation of sterol regulatory-element binding protein (SREBP)-regulated genes, including SCD, which conferred partial protection against NAMPT inhibitors. Inhibition of SREBP signaling with dipyridamole enhanced the cytotoxicity of KPT-9274 on LSCs in vivo. Our work demonstrates that altered lipid homeostasis plays a key role in NAMPT inhibitor-induced apoptosis and identifies NAMPT inhibition as a therapeutic strategy for targeting LSCs in AML.

A novel inhibitor of tumorspheres reveals the activation of the serine biosynthetic pathway upon mitochondrial inhibition.

Differences in the metabolism of cancer cells or cancer stem cells (CSCs) as compared to normal cells have provided avenues to safely target cancers. To discover metabolic inhibitors of CSCs, we performed alkaline phosphatase- and tumoursphere-based drug screening using induced cancer stem cell-like cells. From the screening of a RIKEN NPDepo chemical library, we discovered NPD2381 as a novel and selective cancer-stemness inhibitor that targets mitochondrial metabolism. Using our ChemProteoBase profiling, we found that NPD2381 increases the expression of enzymes within the serine biosynthesis pathway. We also found a role for serine in protecting cancer cells from mitochondrial inhibitors. Our results suggest the existence of a compensatory mechanism to increase the level of intracellular serine in response to mitochondrial inhibitors.

Globular Adiponectin Causes Tolerance to LPS-Induced TNF-α Expression via Autophagy Induction in RAW 264.7 Macrophages: Involvement of SIRT1/FoxO3A Axis.

Adiponectin, an adipokine predominantly produced from adipose tissue, exhibited potent anti-inflammatory properties. In particular, it inhibits production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In the present study, we investigated the role of autophagy induction in the suppression of Lipopolysaccharide (LPS) -induced TNF-α expression by globular adiponectin (gAcrp) and its potential mechanisms. Herein, we found that gAcrp treatment increased expression of genes related with autophagy, including Atg5 and microtubule-associated protein light chain (LC3B), induced autophagosome formation and autophagy flux in RAW 264.7 macrophages. Similar results were observed in primary macrophages isolated peritoneum of mice. Interestingly, inhibition of autophagy by pretreatment with Bafilomycin A1 or knocking down of LC3B gene restored suppression of TNF-α expression, tumor necrosis factor receptor- associated factor 6 (TRAF6) expression and p38MAPK phosphorylation by gAcrp, implying a critical role of autophagy induction in the development of tolerance to LPS-induced TNF-α expression by gAcrp. We also found that knocking-down of FoxO3A, a forkhead box O member of transcription factor, blocked gAcrp-induced expression of LC3II and Atg5. Moreover, gene silencing of Silent information regulator 1 (SIRT1) blocked both gAcrp-induced nuclear translocation of FoxO3A and LC3II expression. Finally, pretreatment with ROS inhibitors, prevented gAcrp-induced SIRT1 expression and further generated inhibitory effects on gAcrp-induced autophagy, indicating a role of ROS production in gAcrp-induced SIRT1 expression and subsequent autophagy induction. Taken together, these findings indicate that globular adiponectin suppresses LPS-induced TNF-α expression, at least in part, via autophagy activation. Furthermore, SIRT1-FoxO3A axis plays a crucial role in gAcrp-induced autophagy in macrophages.

Globular adiponectin modulates expression of programmed cell death 4 and miR-21 in RAW 264.7 macrophages through the MAPK/NF-κB pathway.

MicroRNA-21 and programmed cell death 4 (PDCD4), a downstream target of miR-21, mediate diverse physiological responses. Here we demonstrate that globular adiponectin (gAcrp) modulates expression of miR-21 and PDCD4 in RAW 264.7 macrophages. These effects were abrogated by inhibitors of ERK1/2, JNK or NF-κB. Conditioned media collected from gAcrp-stimulated RAW 264.7 macrophages caused similar effects as direct gAcrp treatment, showing the paracrine effect of gAcrp. These data indicate that gAcrp modulates the miR-21/PDCD4 axis through the ERK and JNK/NF-κB pathways in RAW 264.7 macrophages and further suggest that the miR-21/PDCD4 axis may be a novel target mediating adiponectin-induced biological responses.

Globular adiponectin inhibits ethanol-induced apoptosis in HepG2 cells through heme oxygenase-1 induction.

Hepatocellular apoptosis is an essential pathological feature of alcoholic liver disease. Adiponectin, an adipokine predominantly secreted from adipose tissue, has been shown to play beneficial roles in alcoholic liver disease against various inflammatory and pro-apoptotic molecules. However, the effects of adiponectin on ethanol-induced apoptosis in liver cells are largely unknown. Herein, we investigated the role of globular adiponectin (gAcrp) in the prevention of ethanol-induced apoptosis and further tried to decipher the potential mechanisms involved. In the present study, we demonstrated that gAcrp significantly inhibits both ethanol-induced increase in Fas ligand expression and activation of caspase-3 in human hepatoma cell lines (HepG2 cells), suggesting that gAcrp plays a protective role against ethanol-induced apoptosis in liver cells. This protective effect of gAcrp was mediated through adiponectin receptor R1 (adipoR1). Further, globular adiponectin treatment caused induction of heme oxygenase-1 (HO-1) through, at least in part, nuclear factor (erythroid-derived 2)-like 2, (Nrf2) signaling. Treatment with SnPP, a pharmacological inhibitor of HO-1, and knockdown of HO-1 with small interfering RNA (siRNA) restored caspase-3 activity suppressed by gAcrp, indicating a critical role of HO-1 in mediating the protective role of gAcrp in ethanol-induced apoptosis in liver cells. In addition, carbon monoxide, a byproduct obtained from the catabolism of free heme was found to contribute to the anti-apoptotic effect of adiponectin. In conclusion, these data demonstrated that globular adiponectin prevents ethanol-induced apoptosis in HepG2 cells via HO-1 induction and revealed a novel biological response of globular adiponectin in the protection of liver injury from alcohol consumption.