Clinical trials of R-(-)-gossypol (AT-101) in newly diagnosed and recurrent glioblastoma: NABTT 0602 and NABTT 0702.

PURPOSE: AT-101 is an oral bcl-2 family protein inhibitor (Bcl-2, Bcl-XL, Mcl-1, Bcl-W) and potent inducer of proapoptotic proteins. A prior study of the parent compound, racemic gossypol, demonstrated objective and durable responses in patients with malignant glioma. AT-101 has demonstrated synergy with radiation in animal models. The objectives of trial NABTT 0602 were to determine the MTD of AT-101 concurrent with temozolomide (TMZ) and radiation therapy (RT) (Arm I) and to determine the MTD of AT-101 when given with adjuvant TMZ after completion of standard chemoradiation (Arm 2). Separately in trial NABTT 0702, the survival and response rates of single agent AT-101 were evaluated in patients with recurrent glioblastoma. METHODS: In NABTT 0602 Phase I, a 3+3 design was used to define MTDs after maximal safe resection, patients with newly diagnosed glioblastoma received standard concurrent RT (60 Gy) and TMZ 75 mg/m2/day followed by adjuvant TMZ 150-200 mg/m2 days 1-5 in 28-day cycles (Stupp regimen). In Arm I, AT-101 was administered M-F during the six weeks of RT beginning 20 mg qd. In Arm 2, concurrent with each adjuvant cycle of TMZ, AT-101 was administered at a starting dose of 20 mg, days 1-21 followed by 7-day break for a maximum of 6 cycles. The PK blood samples were collected in the first three patients in each cohort of arm 1. In NABTT 0702 patients with recurrent glioblastoma received 20 mg p.o. per day for 21 of 28 days in repeated cycles to assess overall survival (OS). RESULTS: A total of sixteen patients were enrolled on the two study arms of NABTT 0602. In Arm 1 AT-101 was escalated from 20 to 30 mg where one of six patients experienced DLT (grade 3 GI ulcer). On Arm 2 one patient treated at 20 mg experienced DLT (grade 3 ileus, nausea and diarrhea). The cohort was expanded to include seven patients without observation of DLT. PK results were consistent with drug levels from non-CNS studies. At study closure six patients are still alive. The median survival times for Arm I and Arm II are 15.2 months and 18.2 months, respectively. In NABTT 0702 fifty-six patients were enrolled and forty-three were eligible for imaging response. Sixteen patients (29%) had stable disease as best response and one partial response was observed. The median OS with single agent AT-101 was 5.7 months (95%CI: 3.8-7.6 months) for patients with rGBM. CONCLUSIONS: AT-101 can be safely administered with radiation therapy and TMZ in patients with newly diagnosed glioblastoma without toxicity unique to patients with CNS tumors. Because of toxicity observed in non-CNS AT-101 clinical trials, further dose-escalation was not attempted. The recommended dose for future studies that utilize continual AT-101 exposure is 20 mg days M-F concurrent with RT/TMZ and 20 mg days 1-21 for each 28-day cycle of TMZ. AT-101 has limited activity as a single agent in unselected patients with recurrent glioblastoma. Future trials should attempt to better understand resistance mechanisms and consider combination therapy.

Gossypol improves myocardial dysfunction caused by sepsis by regulating histone acetylation.

Gossypol is a polyphenol from the cotton plant with anti-inflammatory and anti-oxidation activities and can also function as a histone deacetylase (HDAC) inhibitor. Sepsis is an inflammatory disease with high mortality. Inflammation, oxidative stress, and epigenetic factors are involved in sepsis and its complications. The biological activities of gossypol strongly suggest the potential effects of gossypol on sepsis. In the present study, the beneficial effects of gossypol on sepsis were evaluated. We established a cecal ligation and puncture (CLP) mouse model of sepsis and treated CLP mice with gossypol. The survival rate, serum level of myocardial injury markers, and myocardial level of oxidation markers were measured. We also administered gossypol to lipopolysaccharide (LPS)-treated primary cardiomyocytes. The production of pro-inflammatory cytokines, activation of protein kinase B (AKT) and IκB kinase (IKK), acetylation of histone, and expression of HDACs were measured. Gossypol prevented the death of CLP mice and ameliorated myocardial damage in CLP mice. Moreover, gossypol decreased oxidative factors, while promoting antioxidant production in CLP mice. Gossypol prevented LPS and cytosine-phosphate-guanosine-induced expression of pro-inflammatory cytokines, suppressed LPS-induced activation of AKT and IKK, inhibited histone acetylation, and decreased the expression of HDACs. In conclusion, gossypol ameliorates myocardial dysfunction in mice with sepsis.

Doxorubicin-Fe(III)-Gossypol Infinite Coordination Polymer@PDA:CuO2 Composite Nanoparticles for Cost-Effective Programmed Photothermal-Chemodynamic-Coordinated Dual Drug Chemotherapy Trimodal Synergistic Tumor Therapy.

To achieve the maximum therapeutic effects and minimize adverse effects of trimodal synergistic tumor therapies, a cost-effective programmed photothermal (PTT)-chemodynamic (CDT)-coordinated dual drug chemotherapy (CT) trimodal synergistic therapy strategy in chronological order is proposed. According to the status or volumes of the tumors, the intensity and time of each therapeutic modality are optimized, and three modalities are combined programmatically and work in chronological order. The optimal synergistic therapy begins with high-intensity PTT for 10 min to ablate larger tumors, followed by medium-intensity CDT for several hours to eliminate medium-sized tumors, and then low-intensity coordinated dual drugs CT lasts over 48 h to clear smaller residual tumors. Composite nanoparticles, made of Fe-coordinated polydopamine mixed with copper peroxide as the cores and their surface dotted with lots of doxorubicin-Fe(III)-gossypol infinite coordination polymers (ICPs), have been developed to implement the strategy. These composite nanoparticles show excellent synergistic effects with the minimum dose of therapeutic agents and result in nearly 100% tumor inhibition for mice bearing PC-3 tumors and no observed recurrence within 60 days of treatment. The ratios of the different therapeutic agents in the composite nanoparticles can be adjusted to accommodate different types of tumors with this cost-effective programmed trimodal therapy strategy.

Cobalt Ferrite-Gossypol Coordination Nanoagents with High Photothermal Conversion Efficiency Sensitizing Chemotherapy against Bcl-2 to Induce Tumor Apoptosis.

Gossypol is a chemotherapeutic drug that can inhibit the anti-apoptotic protein Bcl-2, but the existing gossypol-related nanocarriers cannot well solve the problem of chemotherapy resistance. Based on the observation that gossypol becomes black upon Fe3+ coordination, it is hypothesized that encasing gossypol in glyceryl monooleate (GMO) and making it coordinate cobalt ferrite will not only improve its photothermal conversion efficiency (PCE) but also help it enter tumor cells. As the drug loading content and drug encapsulation efficiency of gossypol are 10.67% (w/w) and 96.20%, the PCE of cobalt ferrite rises from 14.71% to 36.00%. The synergistic therapeutic effect finally induces tumor apoptosis with a tumor inhibition rate of 96.56%, which is 2.99 and 1.47 times higher than chemotherapy or photothermal therapy (PTT) alone. PTT generated by the GMO nanocarriers under the irradiation of 808 nm laser can weaken tumor hypoxia, thereby assisting gossypol to inhibit Bcl-2. In addition, the efficacy of nanocarriers is also evaluated through T2 -weighted magnetic resonance imaging. Observations of gossypol-induced apoptosis in tissue slices provide definitive proof of chemotherapy sensitization, indicating that such coordination nanocarriers can be used as an effective preclinical agent to enhance chemotherapy.

A biopolymeric mesh enriched with PLGA microparticles loaded with AT101 for localized glioblastoma treatment.

Current treatment strategies for glioblastoma (GBM) including surgical resection and adjuvant radio/chemotherapy result in a limited progression-free survival time of patients due to rapidly occurring tumor recurrences. The urgent need for more effective treatments has led to the development of different approaches for localized drug delivery systems (DDSs) offering the advantages of reduced systemic side effects. A promising candidate for the treatment of GBMs is AT101, the R-(-)-enantiomer of gossypol due to its ability to induce apoptosis or trigger autophagic cell death in tumor cells. Here, we present an alginate-based drug-releasing mesh ladened with AT101-loaded PLGA microspheres (AT101-GlioMesh). The AT101-loaded PLGA microspheres were fabricated using an oil-in-water emulsion solvent evaporation method obtaining a high encapsulation efficiency. The drug-loaded microspheres enabled the release of AT101 over several days at the tumor site. The cytotoxic effect of the AT101-loaded mesh was evaluated using two different GBM cell lines. Strikingly, encapsulation of AT101 in PLGA-microparticles and subsequent embedding in GlioMesh resulted in a sustained delivery and more efficient cytotoxic effect of AT101 on both GBM cell lines. Thus, such a DDS holds promise for GBM therapy likely by preventing the development of tumor recurrences.

Gossypol Reduces Metastasis and Epithelial-Mesenchymal Transition by Targeting Protease in Human Cervical Cancer.

Metastasis is the most prevalent cause of cancer-associated deaths amongst patients with cervical cancer. Epithelial-mesenchymal transition (EMT) is essential for carcinogenesis, and it confers metastatic properties to cancer cells. Gossypol is a natural polyphenolic compound with anti-inflammation, anti-oxidant, and anticancer activities. In this study, we investigated the antimetastatic and antitumour effects of gossypol on human cervical cancer cells (HeLa and SiHa cells). Gossypol exerted a strong inhibition effect on the migration and invasion of human cervical cancer cells. It reduced the focal adhesion kinase (FAK) pathway-mediated expression of matrix metalloproteinase-2 and urokinase-type plasminogen activator, subsequently inhibiting the invasion of SiHa cells. In addition, gossypol reversed EMT induced by transforming growth factor beta 1 (TGF-[Formula: see text]1) and up-regulated epithelial markers, such as E-cadherin but significantly suppressed Ras homolog family member (Rho)A, RhoB, and p-Samd3. The tail vein injection model showed that gossypol treatment via oral gavage reduced lung metastasis. Gossypol also decreased tumour growth in vivo in the nude mouse xenograft model. All these findings suggest that gossypol suppressed the invasion and migration of human cervical cancer cells by targeting the FAK signaling pathway and reversing TGF-[Formula: see text]1-induced EMT. Hence, gossypol warrants further attention for basic mechanistic studies and drug development.

Targeting Oxidative Phosphorylation Reverses Drug Resistance in Cancer Cells by Blocking Autophagy Recycling.

The greatest challenge in cancer therapy is posed by drug-resistant recurrence following treatment. Anticancer chemotherapy is largely focused on targeting the rapid proliferation and biosynthesis of cancer cells. This strategy has the potential to trigger autophagy, enabling cancer cell survival through the recycling of molecules and energy essential for biosynthesis, leading to drug resistance. Autophagy recycling contributes amino acids and ATP to restore mTOR complex 1 (mTORC1) activity, which leads to cell survival. However, autophagy with mTORC1 activation can be stalled by reducing the ATP level. We have previously shown that cytosolic NADH production supported by aldehyde dehydrogenase (ALDH) is critical for supplying ATP through oxidative phosphorylation (OxPhos) in cancer cell mitochondria. Inhibitors of the mitochondrial complex I of the OxPhos electron transfer chain and ALDH significantly reduce the ATP level selectively in cancer cells, terminating autophagy triggered by anticancer drug treatment. With the aim of overcoming drug resistance, we investigated combining the inhibition of mitochondrial complex I, using phenformin, and ALDH, using gossypol, with anticancer drug treatment. Here, we show that OxPhos targeting combined with anticancer drugs acts synergistically to enhance the anticancer effect in mouse xenograft models of various cancers, which suggests a potential therapeutic approach for drug-resistant cancer.

A randomized, double-blind, placebo-controlled study of B-cell lymphoma 2 homology 3 mimetic gossypol combined with docetaxel and cisplatin for advanced non-small cell lung cancer with high expression of apurinic/apyrimidinic endonuclease 1.

Background Overexpression of apurinic/apyrimidinic endonuclease 1 (APE1) is an important cause of poor chemotherapeutic efficacy in advanced non-small cell lung cancer (NSCLC) patients. Gossypol, a new inhibitor of APE1, in combination with docetaxel and cisplatin is believed to improve the efficacy of chemotherapy for advanced NSCLC with high APE1 expression. Methods Sixty-two patients were randomly assigned to two groups. Thirty-one patients in the experimental group received 75 mg/m2 docetaxel and 75 mg/m2 cisplatin on day 1 with gossypol administered at 20 mg once daily on days 1 to 14 every 21 days. The control group received placebo with the same docetaxel and cisplatin regimen. The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), response rate, and toxicity. Results There were no significant differences in PFS and OS between the experimental group and the control group. The median PFS (mPFS) in the experimental and control groups was 7.43 and 4.9 months, respectively (HR = 0.54; p = 0.06), and the median OS (mOS) was 18.37 and 14.7 months, respectively (HR = 0.68; p = 0.27). No significant differences in response rate and serious adverse events were found between the groups. Conclusion The experimental group had a better mPFS and mOS than did the control group, though no significant difference was observed. Because the regimen of gossypol combined with docetaxel and cisplatin was well tolerated, future studies with larger sample sizes should be performed.

A phase I study of AT-101, a BH3 mimetic, in combination with paclitaxel and carboplatin in solid tumors.

Background AT-101 is a BH3 mimetic that inhibits the heterodimerization of Bcl-2, Bcl-xL, Bcl-W, and Mcl-1 with pro-apoptotic proteins, thereby lowering the threshold for apoptosis. This phase I trial investigated the MTD of AT-101 in combination with paclitaxel and carboplatin in patients with advanced solid tumors. Methods Patients were treated with AT-101 (40 mg) every 12 h on days 1, 2 and 3 of each cycle combined with varying dose levels (DL) of paclitaxel and carboplatin [DL1: paclitaxel (150 mg/m2) and carboplatin (AUC 5) on day 1 of each cycle; DL2: paclitaxel (175 mg/m2) and carboplatin (AUC 6) on day 1 of each cycle]. Secondary objectives included characterizing toxicity, efficacy, pharmacokinetics, and pharmacodynamics of the combination. Results Twenty-four patients were treated across two DLs with a planned expansion cohort. The most common tumor type was prostate (N = 11). Two patients experienced DLTs: grade 3 abdominal pain at DL1 and grade 3 ALT increase at DL2; however, the MTD was not determined. Moderate hematologic toxicity was observed. One CR was seen in a patient with esophageal cancer and 4 patients achieved PRs (1 NSCLC, 3 prostate). PD studies did not yield statistically significant decreases in Bcl-2 and caspase 3 protein levels, or increased apoptotic activity induced by AT-101. Conclusion The combination of AT-101 at 40 mg every 12 h on days 1, 2 and 3 combined with paclitaxel and carboplatin was safe and tolerable. Based on the modest clinical efficacy seen in this trial, this combination will not be further investigated. Clinical Trial Registration: NCT00891072, CTEP#: 8016.

Trastuzumab in combination with AT-101 induces cytotoxicity and apoptosis in Her2 positive breast cancer cells.

Aim: AT-101 is a polyphenolic compound with potent anti-apoptotic effects in various cancers. In this study, the possible synergistic cytotoxic and apoptotic effect of trastuzumab/AT-101 combination was investigated in HER2-positive breast cancer cell lines. Materials & methods: SKBR-3, MDA-MB-453 and MCF-10A cell lines were treated with a trastuzumab/AT-101 combination. Synergistic cytotoxicity and apoptosis effects were shown and then PI3K and Akt protein levels were studied. Result: The trastuzumab/AT-101 combination induced synergistic cytotoxicity and apoptosis in both breast cancer cells but not in MCF-10A cells. Combination treatment induced cytotoxicity via inhibiting PI3K/AKT but not the MAPK/ERK pathway. Conclusion: The trastuzumab/AT-101 combination may be a good candidate for patients with trastuzumab-resistant Her2-positive breast cancer and inhibition of the PI3K/AKT pathway may be one of the underlying mechanisms.

A non-intrusive evaluation method for tumor-targeting characteristics of nanomedicines based on in vivo near-infrared fluorescence imaging.

We developed a novel evaluation method for tumor-targeting characteristics of nanomedicines, average tumor-targeting index (average TTI) and "area under the tumor-targeting index-time curve" (AUTC) were established as the indicators for tumor targeting of nanomedicines based on NIR fluorescence imaging, which helps real-time monitoring of targeting ability and tumor changes in vivo without culling animals.

A phase II study of the orally administered negative enantiomer of gossypol (AT-101), a BH3 mimetic, in patients with advanced adrenal cortical carcinoma.

Background Adrenal cortical carcinoma (ACC) is a rare cancer with treatment options of limited efficacy, and poor prognosis if metastatic. AT-101 is a more potent inhibitor of B cell lymphoma 2 family apoptosis-related proteins than its racemic form, gossypol, which showed preliminary clinical activity in ACC. We thus evaluated the efficacy of AT-101 in patients with advanced ACC. Methods Patients with histologically confirmed metastatic, recurrent, or primarily unresectable ACC were treated with AT-101 (20 mg/day orally, 21 days out of 28-day cycles) until disease progression and/or prohibitive toxicity. The primary endpoint was objective response rate, wherein a Response Evaluation Criteria In Solid Tumors (RECIST) partial response rate of 25% would be considered promising and 10% not, with a Type I error of 10% and 90% power. In a 2-stage design, 2 responses were required of the first 21 assessable subjects to warrant complete accrual of 44 patients. Secondary endpoints included safety, progression-free survival and overall survival. Results This study accrued 29 patients between 2009 and 2011; median number of cycles was 2. Seven percent experienced grade 4 toxicity including cardiac troponin elevations and hypokalemia. None of the first 21 patients attained RECIST partial response; accordingly, study therapy was deemed ineffective and the trial was permanently closed. Conclusions AT-101 had no meaningful clinical activity in this study in patients with advanced ACC, but demonstrated feasibility of prospective therapeutic clinical trials in this rare cancer.

Natural Product Gossypol and its Derivatives in Precision Cancer Medicine.

Gossypol, a natural product extracted from the seed, roots, and stem of cotton, was initially used as a male contraceptive but was subsequently investigated as a novel antitumor agent. This review depicts the current status of gossypol and its derivatives as novel antitumor agents as well as presents their preparation and characteristics, especially of some gossypol Schiff bases, through quantitative and structural analysis. The main attractive target sites of gossypol and its derivatives are Bcl-2 family proteins containing the anti-apoptosis proteins Bcl-2 and Bcl-XL. The molecular mechanism of gossypol analogs not only involves cell apoptosis but also autophagy, cell cycle arrest, and other abnormal cellular phenomena. Gossypol and its derivatives exert antitumor effects on different cancer types in vitro and in vivo, and demonstrate synergistic effects with other chemo- and radio- therapeutic treatments. In addition, several nanocarriers have been designed to load gossypol or its derivatives in order to expand the range of their applications and evaluate their combination effects with other anti-tumor agents. This review may serve as a reference for the rational application of gossypol analogs as anti-tumor agents.

Anti-inflammatory Effects of Gossypol on Human Lymphocytic Jurkat Cells via Regulation of MAPK Signaling and Cell Cycle.

Gossypol, a natural polyphenolic compound extracted from cottonseed oil, has been reported to possess pharmacological properties via modulation cell cycle and immune signaling pathway. However, whether gossypol has anti-inflammatory effects against phytohemagglutinin (PHA)-induced cytokine secretion in T lymphocytes through similar mechanism remains unclear. Using the T lymphocytes Jurkat cell line, we found that PHA exposure caused dramatic increase in interleukin-2 (IL-2) mRNA expression as well as IL-2 secretion. All of these PHA-stimulated reactions were attenuated in a dose-dependent manner by being pretreated with gossypol. However, gossypol did not show any in vitro cytotoxic effect at doses of 5-20 µM. As a possible mechanism underlying gossypol action, such as pronounced suppression IL-2 release, robust decreased PHA-induced phosphorylation of p38 and c-Jun N-terminal kinase expressions was found with gossypol pretreatment, but not significant phosphorylation of extracellular signal-regulated kinase expression. Furthermore, gossypol could suppress the Jurkat cells' growth, which was associated with increased percentage of G1/S phase and decreased fraction of G2 phase in flow cytometry test. We conclude that gossypol exerts anti-inflammatory effects probably through partial attenuation of mitogen-activated protein kinase (phosphorylated JNK and p38) signaling and cell cycle arrest in Jurkat cells.

The PPARγ agonist rosiglitazone sensitizes the BH3 mimetic (-)-gossypol to induce apoptosis in cancer cells with high level of Bcl-2.

The BH3 mimetic (-)-gossypol (-)-G has shown promising efficacy to kill several kinds of cancer cells or potentiate current chemotherapeutics. But it induces limited apoptosis in cancer cells with high level of Bcl-2. The nuclear receptor PPARγ and its agonist rosiglitazone can suppress various malignancies. More importantly, rosiglitazone is able to enhance the anti-tumor effects of chemotherapy drugs such as carboplatin and tyrosine kinase inhibitors. In this study, we for the first time demonstrated that rosiglitazone could sensitize (-)-G to induce apoptosis in cancer cells with high level of Bcl-2. Furthermore, we found that (-)-G increased the mRNA level and protein stability of Mcl-1, which weakened the pro-apoptotic effect of (-)-G. Rosiglitazone attenuated the (-)-G-induced Mcl-1 stability through decreasing JNK phosphorylation. Additionally, rosiglitazone upregulated dual-specificity phosphatase 16 (DUSP16), leading to a reduction of (-)-G-triggered JNK phosphorylation. Animal experiments showed that rosiglitazone could sensitize (-)-G to repress the growth of cancer cells with high level of Bcl-2 in vivo. Taken together, our results suggest that the PPARγ agonists may enhance the therapeutic effect of BH3 mimetics in cancers with high level of Bcl-2 through regulating the DUSP16/JNK/Mcl-1 singling pathway. This study may provide novel insights into the cancer therapeutics based on the combination of PPARγ agonists and BH3 mimetics.

Versatile hyaluronic acid modified AQ4N-Cu(II)-gossypol infinite coordination polymer nanoparticles: Multiple tumor targeting, highly efficient synergistic chemotherapy, and real-time self-monitoring.

A novel strategy for the preparation of infinite coordination polymer nanoparticles (ICPs) based nanomedicines was developed, with which hyaluronic acid modified AQ4N-Cu(II)-gossypol nanoparticles (HA@AQ4N-Cu(II)-gossypol NPs) were obtained. This is a highly efficient nanomedicine, in which gossypol serves as a chemotherapeutic agent and a self-carrier material; Cu(II) serves as the connecting point and anti-tumor enhancer; AQ4N not only serves as a chemotherapeutic agent and self-carrier material, but also as the self-monitor based on its inherent fluorescence. HA@AQ4N-Cu(II)-gossypol NPs possessed a spherical shape with a dynamic size of 88.7 ± 7.4 nm, and the total drug-loading content and drug encapsulation efficiency are 77.41% and 100%, respectively. This nanomedicine has a multiple tumor-targeting ability caused by HA-receptor mediation and pH-responsive drug release. A significantly low combination index (0.097) of AQ4N and gossypol is ascertained. In vivo experiments indicate that it accumulates and significantly releases drugs at the tumor region. With the use of only one-fiftieth of AQ4N and half of gossypol of the generally administered dose, they can achieve significantly high anti-tumor efficiency with negligible side effects. Importantly, the switching-type changed fluorescence of AQ4N can be used for in vivo real-time self-monitoring of the drug release and distribution, which allows us to adjust the administration dose and time for different tumor types and stages for individual therapy.

The Development and Current Use of BCL-2 Inhibitors for the Treatment of Chronic Lymphocytic Leukemia.

The BCL-2 family of proteins integrates pro- and anti-apoptotic signals within the cell and is responsible for initiation of caspase-dependent apoptosis. Chronic lymphocytic leukemia (CLL) cells are particularly dependent on the anti-apoptotic protein BCL-2 for their survival, making this an attractive therapeutic target in CLL. Several early efforts to create inhibitors of the anti-apoptotic family members faced significant challenges, but eventually, the BCL-2 specific inhibitor venetoclax moved forward in CLL. Overall and complete response rates to venetoclax monotherapy in relapsed, refractory CLL are approximately 80 and 20%, respectively, even in patients with high-risk 17p deletion. Toxicities have been manageable and include neutropenia, diarrhea, and nausea. The risk of tumor lysis syndrome (TLS), seen in early experience with the drug, has been mitigated by the use of appropriate TLS risk assessment, prophylaxis, and management. Future studies of venetoclax will focus on combination approaches, predictive biomarker discovery, and mechanisms of resistance.

AT-101 enhances gefitinib sensitivity in non-small cell lung cancer with EGFR T790M mutations.

BACKGROUND: Although epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have become the standard care of patients with advanced EGFR-mutant non-small cell lung cancer (NSCLC), development of acquired resistance is inevitable. A secondary mutation of threonine 790 (T790M) is associated with approximately half of the cases of acquired resistance. Strategies or agents to overcome this type of resistance are still limited. In this study, enhanced antitumor effect of AT-101, a-pan-Bcl-2 inhibitor, on gefitinib was explored in NSCLC with T790M mutation. METHODS: The effect of cotreatment with AT-101 and gefitinib on the viability of NSCLC cell lines harboring acquired T790M mutation was investigated using the MTT assay. The cellular apoptosis of NSCLC cells after cotreatment with AT-101 and gefitinib was assessed by FITC-annexin V/PI assay and Western blots analysis. The potential underlying mechanisms of the enhanced therapeutic effect for AT-101 was also studied using Western blots analysis. The in vivo anti-cancer efficacy of the combination with AT-101 and gefitinib was examined in a mouse xenograft model. RESULTS: In this study, we found that treatment with AT-101 in combination with gefitinib significantly inhibited cell proliferation, as well as promoted apoptosis of EGFR TKIs resistant lung cancer cells. The apoptotic effects of the use of AT-101 was related to the blocking of antiapoptotic protein: Bcl-2, Bcl-xl, and Mcl-1 and downregrulation of the molecules in EGFR pathway. The observed enhancements of tumor growth suppression in xenografts supported the reverse effect of AT-101 in NSCLC with T790M mutation, which has been found in in vitro studies before. CONCLUSIONS: AT-101 enhances gefitinib sensitivity in NSCLC with EGFR T790M mutations. The addition of AT-101 to gefitinib is a promising strategy to overcome EGFR TKIs resistance in NSCLC with EGFR T790M mutations.

A phase II trial of the BCL-2 homolog domain 3 mimetic AT-101 in combination with docetaxel for recurrent, locally advanced, or metastatic head and neck cancer.

BACKGROUND: AT-101 is a BCL-2 Homolog domain 3 mimetic previously demonstrated to have tumoricidal effects in advanced solid organ malignancies. Given the evidence of activity in xenograft models, treatment with AT-101 in combination with docetaxel is a therapeutic doublet of interest in metastatic head and neck squamous cell carcinoma. PATIENTS AND METHODS: Patients included in this trial had unresectable, recurrent, or distantly metastatic head and neck squamous cell carcinoma (R/M HNSCC) not amenable to curative radiation or surgery. This was an open label randomized, phase II trial in which patients were administered AT-101 in addition to docetaxel. The three treatment arms were docetaxel, docetaxel plus pulse dose AT-101, and docetaxel plus metronomic dose AT-101. The primary endpoint of this trial was overall response rate. RESULTS: Thirty-five patients were registered and 32 were evaluable for treatment response. Doublet therapy with AT-101 and docetaxel was well tolerated with only 2 patients discontinuing therapy due to treatment related toxicities. The overall response rate was 11 % (4 partial responses) with a clinical benefit rate of 74 %. Median progression free survival was 4.3 months (range: 0.7-13.7) and overall survival was 5.5 months (range: 0.4-24). No significant differences were noted between dosing strategies. CONCLUSION: Although met with a favorable toxicity profile, the addition of AT-101 to docetaxel in R/M HNSCC does not appear to demonstrate evidence of efficacy.

Valproic Acid Enhances the Anti-tumor Effect of (-)-gossypol to Burkitt Lymphoma Namalwa Cells.

Burkitt lymphoma is a highly aggressive B-cell neoplasm. New therapeutic methods are needed to overcome the adverse effect of intensive chemotherapy regimens. Valproic acid and (-)-gossypol are two kinds of chemical compounds used as new anti-tumor drugs in recent years. To investigate the anti-tumor effect of valproic acid and (-)-gossypol, Burkitt lymphoma Namalwa cells were cultured and treated with valproic acid and (-)-gossypol at different concentrations. The proliferation of Namalwa cells was dramatically suppressed after the combination treatment with 2 mmol/L valproic acid and 5 µmol/L (-)-gossypol. The combined treatment also enhanced intrinsic apoptosis by down-regulating anti-apoptotic protein Mcl-1. Moreover, the autophagy flux significantly increased in Namalwa cells after combined treatment. However, the enhanced autophagy showed little effect on cell survival with present regimen. The results confirmed that combination of valproic acid and (-)-gossypol had synergistic anti-tumor effect to Burkitt lymphoma Namalwa cells. The related mechanisms might include the down-regulation of anti-apoptotic protein Mcl-1 and avianized pro-survival role of autophagy.