Idelalisib induces PUMA-dependent apoptosis in colon cancer cells

High-Throughput Drug Screen for Potential Combinations With Venetoclax Guides the Treatment of Transformed Follicular Lymphoma

Transformed follicular lymphoma (t-FL) is an aggressive malignancy that is refractory and rapidly progressing with poor prognosis. There is currently no effective treatment. High-throughput screening (HTS) platforms are used to profile the sensitivity or toxicity of hundreds of drug molecules, and this approach is applied to identify potential effective treatments for t-FL. We randomly selected a compound panel from the School of Pharmaceutical Sciences Xiamen University, tested the effects of the panel on the activity of t-FL cell lines using HTS and the CCK-8 assay, and identified compounds showing synergistic anti-proliferative activity with the Bcl-2 inhibitor venetoclax (ABT-199). Bioinformatics tools were used to analyze the potential synergistic mechanisms. The single-concentration compound library demonstrated varying degrees of activity across the t-FL cell lines evaluated, of which the Karpas422 cells were the most sensitive, but it was the cell line with the least synergy with ABT-199. We computationally identified 30 drugs with synergistic effects in all cell lines. Molecularly, we found that the targets of these 30 drugs didn't directly regulate Bcl-2 and identified 13 medications with high evidence value above .9 of coordination with ABT-199, further confirming TP53 may play the largest role in the synergistic effect. Collectively, these findings identified the combined regimens of ABT-199 and further suggested that the mechanism is far from directly targeting Bcl-2, but rather through the regulation and synergistic action of p53 and Bcl-2. This study intended to reveal the best synergistic scheme of ABT-199 through HTS to more quickly inform the treatment of t-FL.

Downregulation of microRNA‑494 inhibits cell proliferation in lung squamous cell carcinoma via the induction of PUMA‑α‑mediated apoptosis

Increased evidence has shown that abnormal microRNA (miRNA) plays pivotal roles in numerous types of cancer. However, their expression, function and mechanism in lung squamous cell carcinoma (LSCC) remains to be fully elucidated. The aim of the present study was to investigate the suppressive role of miR-494 in LSCC progression and elucidate its regulatory mechanism. By analyzing expression profiles of miRNAs in LSCC tissues using miRNA microarray, it was revealed that miR-494 was significantly upregulated in 22 pairs of LSCC tissues. Subsequently, reverse transcription-quantitative PCR was performed to determine the expression of miR-494 and p53-upregulated-modulator-of-apoptosis-α (PUMA-α). Western blot analysis was conducted to examine protein levels. Dual-luciferase reporter assay was used to confirm the binding between miR-494 and PUMA-α. Annexin V-fluoresceine isothiocyanate/propidium iodide staining and CCK-8 assays were employed to determine cell apoptosis and cell viability, respectively. It was also revealed that miR-494 was highly expressed in LSCC cell lines compared with that in 16HBE cells. Further experiments confirmed that knockdown of miR-494 reduced cell viability and induced LSCC apoptosis. Bioinformatics analysis predicted that miR-494 could potentially target PUMA-α; also known as Bcl-2-binding component 3, a pro-apoptotic factor, and an inverse correlation between the expression of miR-494 and PUMA-α mRNA levels in LSCC tissues was found. Furthermore, PUMA-α inhibition could reverse the promoting effect of miR-494 knockdown on apoptosis in LSCC cells. Taken together, these findings demonstrated that miR-494 functions as an oncogene by targeting PUMA-α in LSCC, and miR-494 may serve as a novel therapeutic target for treating LSCC.

Senolytic Flavonoids Enhance Type-I and Type-II Cell Death in Human Radioresistant Colon Cancer Cells through AMPK/MAPK Pathway

Resistance to cancer therapies remains a clinical challenge and an unsolved problem. In a previous study, we characterized a new colon cancer cell line, namely HT500, derived from human HT29 cells and resistant to clinically relevant levels of ionizing radiation (IR). Here, we explored the effects of two natural flavonoids, quercetin (Q) and fisetin (F), well-known senolytic agents that inhibit genotoxic stress by selectively removing senescent cells. We hypothesized that the biochemical mechanisms responsible for the radiosensitising effects of these natural senolytics could intercept multiple biochemical pathways of signal transduction correlated to cell death resistance. Radioresistant HT500 cells modulate autophagic flux differently than HT29 cells and secrete pro-inflammatory cytokines (IL-8), commonly associated with senescence-related secretory phenotypes (SASP). Q and F inhibit PI₃K/AKT and ERK pathways, which promote p16^INK4 stability and resistance to apoptosis, but they also activate AMPK and ULK kinases in response to autophagic stress at an early stage. In summary, the combination of natural senolytics and IR activates two forms of cell death: apoptosis correlated to the inhibition of ERKs and lethal autophagy dependent on AMPK kinase. Our study confirms that senescence and autophagy partially overlap, share common modulatory pathways, and reveal how senolytic flavonoids can play an important role in these processes.

OSI-027 inhibits the tumorigenesis of colon cancer through mediation of c-Myc/FOXO3a/PUMA axis

Colon cancer is a gastrointestinal malignancy which is one of the leading causes of tumor-associated deaths. It has been reported that mTOR can lead to the progression of colon cancer. However, the mechanism by which mTOR inhibitor (OSI-027) mediates the tumorigenesis of colon cancer remains largely unknown. Cell function of colon cancer was investigated by CCK-8 flow cytometry and TUNEL staining. In addition, qRT-PCR and western blot were used to investigate the mechanism underlying the function of OSI-027 in colon cancer. OSI-027 dose-dependently reduced colon cancer cell viability through inducing the cell apoptosis. In addition, OSI-027 induced the apoptosis of colon cancer cells via upregulation of PUMA. OSI-027 promoted the expression of PUMA by activation of FOXO3a, and c-Myc knockdown partially increased FOXO3a and PUMA level. Moreover, OSI-027 attenuated the tumor growth of colon cancer through mediation of mTOR/c-Myc/FOXO3a axis. OSI-027 attenuates colon cancer progression through mediation of c-Myc/FOXO3a/PUMA axis. Thereby, this research might shed new insights on exploring the strategies against colon cancer. This article is protected by copyright. All rights reserved.

Recent Research Progress of Chiral Small Molecular Antitumor-Targeted Drugs Approved by the FDA From 2011 to 2019

Chiral drugs usually contain chiral centers, which are present as single enantiomers or racemates. Compared with achiral drugs, they have significant advantages in safety and efficacy with high stereoselectivity. Of these drugs, chirality not only exerts influence on the solubility and pharmacokinetic characteristics but also has specific mechanistic characteristics on their targets. We noted that small molecules with unique chiral properties have emerged as novel components of antitumor drugs approved by the FDA in decade. Since approved, these drugs have been continuously explored for new indications, new mechanisms, and novel combinations. In this mini review, recent research progress of twenty-two FDA-approved chiral small molecular-targeted antitumor drugs from 2011 to 2019 is summarized with highlighting the potential and advantages of their applications. We believe that these updated achievements may provide theoretical foundation and stimulate research interests for optimizing drug efficacy, expanding clinical application, overcoming drug resistance, and advancing safety in future clinical administrations of these chiral targeted drugs.

The Role of p53 Dysfunction in Colorectal Cancer and Its Implication for Therapy

Colorectal cancer (CRC) is one of the most common and fatal cancers worldwide. The carcinogenesis of CRC is based on a stepwise accumulation of mutations, leading either to an activation of oncogenes or a deactivation of suppressor genes. The loss of genetic stability triggers activation of proto-oncogenes (e.g., KRAS) and inactivation of tumor suppression genes, namely TP53 and APC, which together drive the transition from adenoma to adenocarcinoma. On the one hand, p53 mutations confer resistance to classical chemotherapy but, on the other hand, they open the door for immunotherapy, as p53-mutated tumors are rich in neoantigens. Aberrant function of the TP53 gene product, p53, also affects stromal and non-stromal cells in the tumor microenvironment. Cancer-associated fibroblasts together with other immunosuppressive cells become valuable assets for the tumor by p53-mediated tumor signaling. In this review, we address the manifold implications of p53 mutations in CRC regarding therapy, treatment response and personalized medicine.

Perifosine enhances the potential antitumor effect of 5-fluorourasil and oxaliplatin in colon cancer cells harboring the PIK3CA mutation

Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutation in colon cancer contributes to the poor prognosis of the disease and chemoresistance of tumors. New therapies are needed; however, the lack of knowledge of the mechanism of chemoresistance has hindered progress. In this study, we investigated the mechanism of the reduced sensitivity of colon cancer cells to 5-fluorouracil (5-FU) and oxaliplatin (L-OHP), and the effects of perifosine, an Akt inhibitor that enhances the cytotoxicity of 5-FU and L-OHP in colon cancer cells harboring the PIK3CA mutation. The use of 5-FU or L-OHP alone or in combination induced significant death of Caco-2 cells (PIK3CA wild type), but only weakly decreased the viability of DLD-1 and SW948 cells harboring the PIK3CA mutation. The use of 5-FU and L-OHP, either alone or in combination, strongly suppressed Akt activation, Survivin, Bcl-2, and Bcl-xL expression, and enhanced Puma, phospho-p53, and p53 expression in Caco-2 cells than in DLD-1 cells. In addition, perifosine enhanced the cytotoxicity of the 5-FU and L-OHP combination, inhibited Akt activation and the expression of Survivin, Bcl-2, and Bcl-xL, and increased the expression of Puma, phospho-p53, and p53 in DLD-1 cells. These results indicate that PIK3CA mutation contributes to reduced sensitivity to 5-FU and L-OHP via Akt activation in colon cancer cells. Perifosine increases the efficacy of 5-FU and L-OHP by suppressing Akt activation. Thus, the use of an Akt inhibitor in combination with 5-FU and L-OHP may be beneficial in colon cancer with cells harboring the PIK3CA mutation.

p110δ PI3K as a therapeutic target of solid tumours

From the time of first characterization of PI3K as a heterodimer made up of a p110 catalytic subunit and a regulatory subunit, a wealth of evidence have placed the class IA PI3Ks at the forefront of drug development for the treatment of various diseases including cancer. The p110α isoform was quickly brought at the centre of attention in the field of cancer research by the discovery of cancer-specific gain-of-function mutations in PIK3CA gene in a range of human solid tumours. In contrast, p110δ PI3K was placed into the spotlight of immunity, inflammation and haematologic malignancies because of the preferential expression of this isoform in leucocytes and the rare mutations in PIK3CD gene. The last decade, however, several studies have provided evidence showing that the correlation between the PIK3CA mutations and the response to PI3K inhibition is less clear than originally considered, whereas concurrently an unexpected role of p110δ PI3K in solid tumours has being emerging. While PIK3CD is mostly non-mutated in cancer, the expression levels of p110δ protein seem to act as an intrinsic cancer-causing driver in various solid tumours including breast, prostate, colorectal and liver cancer, Merkel-Cell carcinoma, glioblastoma and neurobalstoma. Furthermore, p110δ selective inhibitors are being studied as potential single agent treatments or as combination partners in attempt to improve cancer immunotherapy, with both strategies to shown great promise for the treatment of several solid tumours. In this review, we discuss the evidence implicating the p110δ PI3K in human solid tumours, their impact on the current state of the field and the potential of using p110δ-selective inhibitors as monotherapy or combined therapy in different cancer contexts.

Idelalisib induces apoptosis in the lymphoid tissues and impairs lung function in mice

Idelalisib, an inhibitor of the phosphatidylinositol-3-kinase p110δ subunit (PI3Kδ), is approved for treating lymphoid malignancy. The drug is associated with hematopoietic and pulmonary toxicities, which limit its clinical use. However, the toxicity mechanisms are not completely elucidated. In this study, mice were intraperitoneally injected with idelalisib (40 or 80 µg/g) or dimethyl sulfoxide for five days every week for up to four weeks to evaluate the changes in the thymus, spleen, and pulmonary functions. Idelalisib treatment induced thymic involution, decreased CD4⁺/CD8⁺ T-cell population, and increased CD4^-/CD8^- T-cell population. In the spleen, idelalisib dose dependently decreased the lymphocyte viability and cell count. Idelalisib-treated mice exhibited enhanced cleaved caspase-3 expression in the thymus, spleen, and lung tissues. Idelalisib augmented thoracic and airway resistance and decreased thoracic compliance. Thus, PI3Kδ has physiological roles in T-cell development and airway function. Monitoring drug toxicity is important for developing follow-up compounds that target PI3Kδ signalling.

Emerging treatment options for patients with p53-pathway-deficient CLL

Over the past 40 years, p53 has been the most widely studied protein in cancer biology. Originally thought to be an oncogene due to its stabilization in many cancers, it is now considered to be one of the most critical tumor suppressors in a cell's ability to combat neoplastic transformation. Due to its critical roles in apoptosis, cell-cycle arrest, and senescence, TP53 deletions and mutations are commonly observed and are often a portent of treatment failures and poor clinical outcomes. This is particularly true in chronic lymphocytic leukemia (CLL), as patients with p53 alterations have historically had dismal outcomes. As such, the tremendous efforts made to better understand the functions of p53 in CLL have contributed substantially to recent advances in treating patients with p53-pathway-deficient CLL.

Mutant p53 drives cancer chemotherapy resistance due to loss of function on activating transcription of PUMA

P53 is a critical tumor suppressor gene, activating p53 and its downstream targets to induce apoptosis is a promising way for cancer therapy. However, more than 50% of cancer patients have p53 mutations, which may cause cancer therapy resistance, and the underline mechanism is poorly understood. Here, we found that cell viability decrease and apoptosis induced by p53-dependent traditional drugs in colon cancer cells were eliminated in p53 mutant cells. Mutant p53 did not up-regulate the expression of its direct downstream targets PUMA and p21, due to the inhibition of PUMA transcription. Furthermore, mutant p53 could not bind to the promoter of PUMA to activate its transcription like WT p53 did, while overexpressed WT p53 rescued PUMA-induced subsequent apoptosis. In conclusion, our findings demonstrate mutant p53 may cause chemo-resistance of tumor because of inactivating PUMA transcription, which prompts some new insights for clinical therapy of cancer patients with mutant p53.Abbreviations: CRC: Colorectal cancer; CDKs: Cyclin-dependent kinases; PUMA: p53 up-regulated modulator of apoptosis; PDGF: the platelet-derived growth factor; WT p53: wild-type p53 protein; mutp53: mutant p53 proteins; BAX: Bcl-2-associated X protein; NOXA: Phorbol-12-myristate-13-acetate-induced protein 1.

Novel insights into the evolution of the caveolin superfamily and mechanisms of antiapoptotic effects and cell proliferation in lamprey

Caveolin-1 is the main structural and functional component of caveolin, and it is involved in the regulation of cholesterol transport, endocytosis, and signal transduction. Moreover, changes in caveolin-1 play an important role in tumorigenesis and inflammatory processes. Previous studies have demonstrated that human caveolin-1 is mainly located in the cell membrane and exhibits cell type- and stage-dependent functional differences during cancer development and inflammatory responses. However, the role of Lamprey-caveolin-like (L-caveolin-like) in lamprey remained unknown. Here, we demonstrated that L-caveolin-like performs anti-inflammation and oncogenic functions and the function of caveolin-1 diverged during vertebrate evolution. Moreover, the results reveal the mechanism underlying the antiapoptotic effects of L-caveolin-like. An L-caveolin-like gene from Lampetra japonica (L. japonica) was identified and characterized. L-Caveolin-like was primarily distributed in the leukocytes, intestines and supraneural bodies (Sp-bodies) immune organs as indicated by Q-PCR and immunohistochemistry assays. The mRNA and protein expression levels of L-caveolin exhibited consistent increases in expression at 2 and 72 h in adult tissues after exposure to lipopolysaccharide (LPS) and in leukocytes stimulated by Vibrio anguillarum (V. anguillarum), Staphylococcus aureus (S. aureus), and Poly I:C. Furthermore, the overexpression of pEGFP-N1-L-caveolin-like was associated with a distinct localization in mitochondria, with decreased cytochrome C (Cyt C) and mitochondrial Cyt C oxidase subunit I (CO I) expression. In addition, increased cellular ATP levels suggested that this protein prevented mitochondrial damage. The overexpression of pEGFP-N1-L-caveolin-like led to the altered expression of factors related to apoptosis, such as decreased Caspase-9, Caspase-3, p53, and Bax expression and increased Bcl-2 expression. In addition, the overexpression of pEGFP-N1-L-caveolin-like promoted cell proliferation associated with upregulated EGF, bFGF, and PDGFB expression. Together, these findings indicated that the L-caveolin-like protein from L. japonica induced the activation of antiapoptotic effects via the mitochondrial Cyt C-mediated Caspase-3 signaling pathway. Our analysis further suggests that L-caveolin-like is an oncogene protein product and anti-inflammatory molecule from lamprey that evolved early in vertebrate evolution.

Targeting Akt by SC66 triggers GSK-3β mediated apoptosis in colon cancer therapy

Background

Colon cancer is one of the three common malignant tumors, with lower 5 years survival rate. Akt is an important therapeutic target, while SC66 is a novel allosteric AKT inhibitor, which enhances the therapeutic effect in several types of cancer. However, the molecular mechanisms of targeting AKT by SC66 during colon cancer therapy are not well understood.

Methods

The biological role of GSK-3β in colon cancer growth suppression induced by SC66 was detected in vitro and in vivo. Hoechst 33342 and crystal violet staining were used to determine whether targeting AKT affected apoptosis and cell proliferation. The CCK8 assay was utilized to analyze cell viability. The expression levels of Akt, GSK-3β, Bax, Bcl-xL, p53 and PUMA were measured by immune blotting. Xenograft mouse model was established to study the antitumor effect of SC66 in vivo.

Results

Our results show that SC66 induced significantly colon cancer cell apoptosis, accompanied with Akt inactivation. After AKT inhibition, activated GSK-3β interacted with Bax directly, leading to Bax oligomerization and activation. Knocking down GSK-3β abrogated SC66-triggered Bax activation and apoptosis, which was enhanced by over-expressed GSK-3β. In addition, the expression level of Bcl-xL was down-regulated while p53 had no function during SC66-induced apoptosis. Furthermore, colon cancer growth was suppressed by SC66 therapy in vivo.

Conclusion

Taken together, these data indicated that the novel small molecule AKT inhibitor SC66 shows visible antitumor effects via the AKT/GSK-3β/Bax axis in vitro and in vivo. Our results provide a rational basis for the development of targeting-GSK-3β, which may serve as a potential biomarker and yield meaningful benefits for colon cancer patients in the future.

Crosstalk Between Connexin32 and Mitochondrial Apoptotic Signaling Pathway Plays a Pivotal Role in Renal Ischemia Reperfusion-Induced Acute Kidney Injury

Aims: Perioperative acute kidney injury (AKI) resulting from renal ischemia reperfusion (IR) is not conducive to the postoperative surgical recovery. Our previous study demonstrated that reactive oxygen species (ROS) transmitted by gap junction (GJ) composed of connexin32 (Cx32) contributed to AKI. However, the precise underlying pathophysiologic mechanisms were largely unknown. This study focuses on the underlying mechanisms related to ROS transmitted by Cx32 responsible for AKI aggravation. Results: In a set of in vivo studies, renal IR was found to cause severe impairment in renal tissues with massive ROS generation, which occurred contemporaneously with activation of NF-κB/p53/p53 upregulated modulator of apoptosis (PUMA)-mediated mitochondrial apoptosis pathways. Cx32 deficiency alleviated renal IR-induced AKI, and simultaneously attenuated ROS generation and distribution in renal tissues, which further inhibited NF-κB/p53/PUMA-mediated mitochondrial apoptotic pathways. Correspondingly, in a set of in vitro studies, hypoxia reoxygenation (HR)-induced cellular injury, and cell apoptosis in both human kidney tubular epithelial cells (HK-2s) and rat kidney tubular epithelial cells (NRK52Es) were significantly attenuated by Cx32 inhibitors or Cx32 gene knockdown. More importantly, Cx32 inhibition not only decreased ROS generation and distribution in human or rat kidney tubular epithelial cells but also inhibited its downstream NF-κB/p53/PUMA-mediated mitochondrial apoptotic pathway activation. Innovation and Conclusion: This is the first identification of the underlying mechanisms of IR-induced renal injury integrally which demonstrates the critical role played by Cx32 in IR-induced AKI. Moreover, GJ composed of Cx32 manipulates ROS generation and distribution between neighboring cells, and alters activation of NF-κB/p53/PUMA-mediated mitochondrial apoptotic pathways. Both inhibiting Cx32 function and scavenging ROS effectively reduce mitochondrial apoptosis and subsequently attenuate AKI, providing effective strategies for kidney protection.

Trastuzumab induces PUMA-dependent apoptosis and inhibits tumor growth in gastric cancer

Gastric cancer (GC) is one of the most prevalent cancers worldwide. Trastuzumab has been approved for the treatment of metastatic GC, gastroesophageal junction cancer, and breast cancer. However, the mechanisms involved in trastuzumab-induced GC cell apoptosis remain largely unknown. In this study, we investigated the underlying mechanisms of trastuzumab-mediated suppression of GC cell growth both in vitro and in vivo. We found that trastuzumab treatment induces p53 upregulated modulator of apoptosis (PUMA) expression in GC cells, through the NF-κB pathway following AKT inhibition and glycogen synthase kinase 3β (GSK3β) activation. We also observed that PUMA was necessary for trastuzumab-induced apoptosis in GC cells. Moreover, PUMA deficiency suppressed apoptosis and the antitumor effect of trastuzumab in xenograft models. Finally, computerized tomography (CT) and immunohistochemistry results showed that patients with increased activation of PUMA were more sensitive to trastuzumab treatment than those with low PUMA expression. These results indicate that trastuzumab induces PUMA-dependent apoptosis and inhibits tumor growth in GC, suggesting that PUMA plays a critical role in mediating the antitumor effects of trastuzumab in GC. PUMA induction may be used as a marker of trastuzumab sensitivity.

Idelalisib promotes Bim-dependent apoptosis through AKT/FoxO3a in hepatocellular carcinoma

Idelalisib, a selective PI3Kδ inhibitor, has been approved by the FDA for chronic lymphocytic leukemia/small lymphocytic lymphoma treatment and for follicular lymphoma treatment when combined with rituximab. However, the mechanisms of effective action of idelalisib in hepatocellular carcinoma (HCC) remain unclear. In the current study, we aimed to investigate how idelalisib inhibits the growth of HCC cells and enhances the effects of other chemotherapeutic drugs. Our results show that idelalisib treatment promotes Bim induction in HCC via the FoxO3a pathway following PI3K/AKT inactivation. Moreover, our results show that Bim is required for idelalisib-mediated apoptosis in HCC. Idelalisib also synergizes with sorafenib or doxorubicin to induce significant apoptosis in HCC, and Bim is also necessary for the induction of apoptosis by cotreatment. Furthermore, a xenograft experiment reveals that the Bim deficiency abolishes apoptosis and antitumor effects of idelalisib in vivo. In summary, our results indicate a key role of Bim in mediating the antitumor effects of idelalisib in HCC. Our results also support the clinical significance of the drug.

Ipatasertib, a novel Akt inhibitor, induces transcription factor FoxO3a and NF-κB directly regulates PUMA-dependent apoptosis

Colon cancer is one of the three common malignant tumors, with a lower survival rate. Ipatasertib, a novel highly selective ATP-competitive pan-Akt inhibitor, shows a strong antitumor effect in a variety of carcinoma, including colon cancer. However, there is a lack of knowledge about the precise underlying mechanism of clinical therapy for colon cancer. We conducted this study to determine that ipatasertib prevented colon cancer growth through PUMA-dependent apoptosis. Ipatasertib led to p53-independent PUMA activation by inhibiting Akt, thereby activating both FoxO3a and NF-κB synchronously that will directly bind to PUMA promoter, up-regulating PUMA transcription and Bax-mediated intrinsic mitochondrial apoptosis. Remarkably, Akt/FoxO3a/PUMA is the major pathway while Akt/NF-κB/PUMA is the secondary pathway of PUMA activation induced by ipatasertib in colon cancer. Knocking out PUMA eliminated ipatasertib-induced apoptosis both in vitro and in vivo (xenografts). Furthermore, PUMA is also indispensable in combinational therapies of ipatasertib with some conventional or novel drugs. Collectively, our study demonstrated that PUMA induction by FoxO3a and NF-κB is a critical step to suppress the growth of colon cancer under the therapy with ipatasertib, which provides some theoretical basis for clinical assessment.

Apoptosis induced by methanol extract of Potentilla discolor in human mucoepidermoid carcinoma cells through STAT3/PUMA signaling axis

Potentilla discolor has been used in traditional Chinese medicine for the treatment of hyperglycemia. However, the potential role of Potentilla discolor against cancer and its mode of action remain to be fully elucidated. The present study explored the apoptotic effect of methanol extract of Potentilla discolor (MEPD) in human mucoepidermoid carcinoma (MEC) cell lines of salivary glands. MEPD markedly suppressed the growth and induced apoptotic cell death in MC3 and YD15 cells. MEPD treatment significantly upregulated the expression of PUMA and reduced STAT3 phosphorylation. Overexpression of STAT3 partially recovered the growth of MEC cells inhibited by MEPD. In addition, dephosphorylation of STAT3 by cryptotanshinone (a potent STAT3 inhibitor) was sufficient to inhibit the growth of MEC cells and induce apoptosis via affecting PUMA protein. These results suggest that MEPD has a potential anticancer property via the STAT3/PUMA signaling axis in human MEC cells of salivary gland.

NVP-BKM120 inhibits colon cancer growth via FoxO3a-dependent PUMA induction

NVP-BKM120, a potent and highly selective PI3K inhibitor, is currently being investigated in phase I/II clinical trials. The mechanisms of action of NVP-BKM120 in colon cancer cells are unclear. In the present study, we investigated how NVP-BKM120 suppresses colon cancer cells growth and potentiates effects of other chemotherapeutic drugs. We found that NVP-BKM120 treatment enhance PUMA induction irrespective of p53 status through the FoxO3a pathway following AKT inhibition. Furthermore, PUMA is required for NVP-BKM120-induced apoptosis in colon cancer cells. In addition, NVP-BKM120 also synergized with 5-Fluorouracil or regorafenib to induce marked apoptosis via PUMA induction. Deficiency of PUMA suppressed apoptosis and antitumor effect of NVP-BKM120 in xenograft model. These results demonstrate a key role of PUMA in mediating the anticancer effects of NVP-BKM120 and suggest that PUMA could be used as an indicator of NVP-BKM120 sensitivity, and also have important implications for it clinical applications.

TRAIL, Wnt, Sonic Hedgehog, TGFβ, and miRNA Signalings Are Potential Targets for Oral Cancer Therapy

Clinical studies and cancer cell models emphasize the importance of targeting therapies for oral cancer. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is highly expressed in cancer, and is a selective killing ligand for oral cancer. Signaling proteins in the wingless-type mouse mammary tumor virus (MMTV) integration site family (Wnt), Sonic hedgehog (SHH), and transforming growth factor β (TGFβ) pathways may regulate cell proliferation, migration, and apoptosis. Accordingly, the genes encoding these signaling proteins are potential targets for oral cancer therapy. In this review, we focus on recent advances in targeting therapies for oral cancer and discuss the gene targets within TRAIL, Wnt, SHH, and TGFβ signaling for oral cancer therapies. Oncogenic microRNAs (miRNAs) and tumor suppressor miRNAs targeting the genes encoding these signaling proteins are summarized, and the interactions between Wnt, SHH, TGFβ, and miRNAs are interpreted. With suitable combination treatments, synergistic effects are expected to improve targeting therapies for oral cancer.