Salvage regional therapy using hepatic artery infusion pump in unresectable chemotherapy resistant colorectal liver metastases.

BACKGROUND: Little is known about the influence of hepatic artery infusion pump (HAIP) therapy in the setting of chemotherapy resistant hepatic disease in the era of modern systemic therapies. METHODS: Patients who underwent HAIP therapy for chemotherapy resistant and unresectable colorectal liver metastases (CRLM) were reviewed retrospectively. RESULTS: A total of 25 patients met inclusion criteria. 52% had isolated CRLM and 92% had five or more metastatic lesions. Partial response was noted in 40% of patients. Median hepatic progression-free survival (PFS) was 7 months in those with extrahepatic disease versus 6 months in those with isolated CRLM at the time of HAIP placement (p = 0.75). Median overall survival was 8 months in patients with extrahepatic disease and 14 months in patients with isolated CRLM (p = 0.06). CONCLUSIONS: Our findings are comparable to published data and augment the literature which supports HAIP use in chemotherapy-resistant, liver-predominant metastatic colorectal cancer patients.

Pneumocystis jirovecii: a review with a focus on prevention and treatment.

Introduction: Pneumocystis jirovecii (PJ) is an opportunistic fungal pathogen that can cause severe pneumonia in immunocompromised hosts. Risk factors for Pneumocystis jirovecii pneumonia (PJP) include HIV, organ transplant, malignancy, certain inflammatory or rheumatologic conditions, and associated therapies and conditions that result in cell-mediated immune deficiency. Clinical signs of PJP are nonspecific and definitive diagnosis requires direct detection of the organism in lower respiratory secretions or tissue. First-line therapy for prophylaxis and treatment remains trimethoprim-sulfamethoxazole (TMP-SMX), though intolerance or allergy, and rarely treatment failure, may necessitate alternate therapeutics, such as dapsone, pentamidine, atovaquone, clindamycin, primaquine and most recently, echinocandins as adjunctive therapy. In people living with HIV (PLWH), adjunctive corticosteroid use in treatment has shown a mortality benefit.Areas covered: This review article covers the epidemiology, pathophysiology, diagnosis, microbiology, prophylaxis indications, prophylactic therapies, and treatments.Expert opinion: TMP-SMX has been first-line therapy for treating and preventing pneumocystis for decades. However, its adverse effects are not uncommon, particularly during treatment. Second-line therapies may be better tolerated, but often sacrifice efficacy. Echinocandins show some promise for new combination therapies; however, further studies are needed to define optimal antimicrobial therapy for PJP as well as the role of corticosteroids in those without HIV.

Regorafenib and Nivolumab or Pembrolizumab Combination and Circulating Tumor DNA Response Assessment in Refractory Microsatellite Stable Colorectal Cancer.

BACKGROUND: Metastatic colorectal cancers (MCRCs) with microsatellite stability (MSS) are resistant to immunotherapy with programmed cell death protein 1 (PD-1) and programmed death-ligand 1 inhibitors. However, the addition of regorafenib to nivolumab was recently associated with a high response rate and a protracted progression-free survival in a small cohort of MSS Japanese patients with metastatic colorectal cancer. MATERIALS AND METHODS: We evaluated the outcome of patients with MSS metastatic colorectal cancer who were treated on a compassionate basis with PD-1 inhibitors in combination with regorafenib in a single U.S. center. RESULTS: A total of 18 patients were treated with a combination of regorafenib and PD-1 inhibitors. No treatment-related grade 3 or above toxicities were noted. Thirteen patients (69%) had progressive disease, and five patients (31%) experienced stable disease as best response. Four out of five stable diseases occurred in patients without liver metastases, whereas only 1 of 14 patients with history of liver metastases had a short disease stabilization. A rise in circulating tumor DNA (ctDNA) at the 4-week time pointuniversally predicted tumor progression at 2 months, whereas a decline was associated with radiographic disease stabilization. CONCLUSIONS: Regorafenib and nivolumab combination was associated with modest clinical activity in patients with MSS chemotherapy-resistant metastatic colorectal cancer. Selection for patients without history of liver metastases may identify a cohort of patients with MSS colorectal cancer with a higher likelihood of benefit from this combination. ctDNA may represent a powerful tool for predicting early therapeutic efficacy of immunotherapy in the MSS colorectal cancer population. IMPLICATIONS FOR PRACTICE: This study showed that the combination of regorafenib and nivolumab was associated with a modest clinical activity in patients with advanced microsatellite stability (MSS) metastatic colorectal cancer. This combination should be avoided in clinical practice, especially in patients with MSS colorectal cancer with liver metastases. Further investigation of regorafenib plus PD-1 inhibitors should be considered in MSS colorectal cancer without liver metastases.

Curcumin: An age-old anti-inflammatory and anti-neoplastic agent.

Curcumin is a natural anti-inflammatory agent that has been used for treating medical conditions for many years. Several experimental and pharmacologic trials have demonstrated its efficacy in the role as an anti-inflammatory agent. Curcumin has been shown to be effective in treating chronic conditions like rheumatoid arthritis, inflammatory bowel disease, Alzheimer's and common malignancies like colon, stomach, lung, breast, and skin cancers. As treatments in medicine become more and more complex, the answer may be something simpler. This is a review article written with the objective to systematically analyze the wealth of information regarding the medical use of curcumin, the "curry spice", and to understand the existent gaps which have prevented its widespread application in the medical community.

App Use in Psychiatric Education: A Medical Student Survey.

OBJECTIVE: The objective of the study is to understand and appraise app use by medical students during their clerkships. METHODS: Following Creighton University IRB approval, a voluntary and anonymous paper-based, 15-question survey was distributed to third-year medical students. Data were analyzed using Microsoft Excel. RESULTS: Of 112 medical students available, 76.7% (86) participated in the survey. All participants owned a smartphone or tablet with 84.9% using Apple iOS, followed by 12.8% using Android platform. Students reported using the fewest number of apps during surgery, psychiatry, and obstetrics and gynecology clerkships. The largest number of apps were used during the internal medicine rotation (70.3%). The three most popular apps were Epocrates, UpToDate, and UWorld. The most common uses for these apps were as references during the clerkship, followed by improving knowledge, and test taking. Perceived major benefits included accessibility (96% of student respondents) and interactivity (39.5%). Common apps used during the psychiatry clerkship included UpToDate (71%), Epocrates (51%), and Medscape (43%). Despite less frequent app use during their psychiatry clerkship, 90% felt there was a utility for educational apps in psychiatric education. CONCLUSIONS: Consistent with the previous literature on medical students preferring educational apps, students suggest developers focus on question bank-type apps, followed by clinical support-focused and self-directed case-based learning apps for psychiatry clerkship learning. Educators should factor these modes of educational delivery into future educational app development. This survey shows a high degree of smartphone and tablet use among medical students, and they attest to mobile phone app utility in psychiatric education.

Impact of RAS and BRAF mutations on carcinoembryonic antigen production and pattern of colorectal metastases.

AIM: To investigate the impact of RAS and BRAF mutations on the pattern of metastatic disease and carcinoembryonic antigen (CEA) production. METHODS: In this retrospective study, we investigated the impact of RAS and BRAF mutational status on pattern of metastatic disease and CEA production. Only patients presenting with a newly diagnosed metastatic colorectal cancer (CRC) were included. Patients' characteristics, primary tumor location, site of metastatic disease and CEA at presentation were compared between those with and without RAS and BRAF mutations. RESULTS: Among 174 patients, mutations in KRAS, NRAS and BRAF were detected in 47%, 3% and 6% respectively. RAS mutations (KRAS and NRAS) were more likely to be found in African American patients (87% vs 13%; P value = 0.0158). RAS mutations were associated with a higher likelihood of a normal CEA (< 5 ng/mL) at presentation. BRAF mutations were more likely to occur in females. We were not able to confirm any association between mutational status and site of metastatic disease at initial diagnosis. CONCLUSION: No association was found between RAS and BRAF mutations and sites of metastatic disease at the time of initial diagnosis in our cohort. Patients with RAS mutations were more likely to present with CEA levels < 5 ng/mL. These findings may have clinical implications on surveillance strategies for RAS mutant patients with earlier stages of CRC.

TP53-induced glycolysis and apoptosis regulator promotes proliferation and invasiveness of nasopharyngeal carcinoma cells.

The TP53-induced glycolysis and apoptosis regulator (TIGAR) is the protein product of the p53 target gene, C12orf5. TIGAR blocks glycolysis and promotes cellular metabolism via the pentose phosphate pathway; it promotes the production of cellular nicotinamide adenine dinucleotide phosphate (NADPH), which leads to enhanced scavenging of intracellular reactive oxygen species, and inhibition of oxidative stress-induced apoptosis in normal cells. Our previous study identified a novel nucleoside analog that inhibited cellular growth and induced apoptosis in nasopharyngeal carcinoma (NPC) cell lines via downregulation of TIGAR expression. Furthermore, the growth inhibitory effects of c-Met tyrosine kinase inhibitors were ameliorated by the overexpression of TIGAR in the NPC cell lines. These results indicate a significant role for TIGAR expression in the survival of NPCs. The present study aimed to further define the function of TIGAR expression in NPC cells. In total, 36 formalin-fixed, paraffin-embedded NPC tissue samples were obtained for the immunohistochemical determination of TIGAR expression. The effects of TIGAR expression on cell proliferation, NADPH production and cellular invasiveness were also assessed in NPC cell lines. Overall, TIGAR was overexpressed in 27/36 (75%) of the NPC tissues compared with the adjacent non-cancer epithelial cells. Similarly, TIGAR overexpression was also observed in a panel of six NPC cell lines compared with normal NP460 hTert and Het1A cell lines. TIGAR overexpression led to increased cellular growth, NADPH production and invasiveness of the NPC cell lines, whereas a knockdown of TIGAR expression resulted in significant inhibition of cellular growth and invasiveness. The expression of the two mesenchymal markers, fibronectin and vimentin, was increased by TIGAR overexpression, but reduced following TIGAR-knockdown. The present study revealed that TIGAR overexpression led to increased cellular growth, NADPH production and invasiveness, and the maintenance of a mesenchymal phenotype, in NPC tissues.

Preclinical evaluation of the mTOR-PI3K inhibitor BEZ235 in nasopharyngeal cancer models.

The dual PI3K-mTOR inhibitor BEZ235 was evaluated in preclinical models of nasopharyngeal carcinoma (NPC). The IC50 value of BEZ235 for growth was in the nanomolar range in vitro, induce G1 cycle arrest and apoptosis, and inhibited AKT and mTOR signaling in most NPC cell lines. No synergistic effect was observed when BEZ235 was combined with chemotherapy. BEZ235 increased MAPK activation in vitro but not in vivo. A daily schedule was more effective than a weekly schedule on tumor growth and inhibition of downstream mTOR signaling in vivo. The activity of BEZ235 maybe independent of the PIK3CA amplification and mutation status.

Preclinical evaluation of the PI3K-mTOR dual inhibitor PF-04691502 as a novel therapeutic drug in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is common in Southeast Asia and over 40% of NPC tissues have PIK3CA amplification. This study characterized the preclinical activity of a novel potent dual PI3K/mTOR inhibitor, PF-04691502, in five NPC cell lines: CNE-1, HK1, CNE-2, HONE-1 and C666-1, in which all of the cell lines possessed basal and activated expression of Akt and p70S6K. Over 80% inhibition of cell growth in all of these cell lines were achieved after 72 h of PF-04691502 incubation and their IC50 were in hundred nanomolar range. CNE-2, HK1 and HONE-1 were selected to further evaluate the effect of PF-04691502 on cell cycle, apoptosis and Akt downstream signaling. PF-04691502 induced G0/G1 cell cycle arrest and apoptosis at 24 h incubation and it significantly abrogated Akt and its downstream signaling by suppressing the expression of p-mTOR, p-p70S6K, p-Akt(S473, T308), p-S6 and p-4E-BP1, suggesting its effectiveness in inhibition of translation and protein synthesis. Anti-proliferation was also observed in 3D culture system and spheroids formation of NPC cell line HONE-1-EBV was strongly inhibited by PF-04691502. Antitumor activity was observed in CNE-2 xenograft in 2 weeks of 10 mg/kg PF-09641502 treatment to tumor bearing athymic nude mice. Both tumor volume and weight in treatment group were significantly lower than those in vehicle group while no obvious body weight decrease was found, suggesting this working dose was effective and well-tolerated. Additive effects were observed in combination of PF-09641502 with either cisplatin or paclitaxel. There were no synergistic effect observed in drug combination but PF-09641502 alone was effective in treating cisplatin resistant cell lines as compared to its parental control. The beneficial effects of PF-09641502 in both in vitro and in vivo studies for NPC warrant a further investigation.

Risk factors for venous thromboembolism in critically ill nontrauma surgical patients who cannot receive chemical prophylaxis.

BACKGROUND: We sought to identify independent predictors of venous thromboembolism in critically ill general surgery patients who cannot receive chemical prophylaxis in order to identify those who may benefit from aggressive screening and/or prophylactic inferior vena cava filter placement. METHODS: Nontrauma patients in the surgical intensive care unit were prospectively followed for 2 years. Patients who had contraindications to prophylactic anticoagulation and received routine screening duplex examinations were included. Data regarding lower-extremity deep venous thrombosis or pulmonary embolism (PE) rates, past medical history (PMH), surgeries, and transfusions were collected. Logistic regression was used to identify independent predictors of lower-extremity deep venous thrombosis or PE (venous thromboembolism) with a P < .05. RESULTS: Data were complete for 204 patients. Twenty (9.8%) patients developed venous thromboembolism. Independent predictors of venous thromboembolism included postoperative blood product requirements (odds ratio = 1.04 per unit), a PMH of PE (OR = 10.1), and a PMH of renal insufficiency (odds ratio = 5.1). CONCLUSIONS: Aggressive screening and/or prophylactic inferior vena cava filter may be considered when prophylactic anticoagulation is prohibited in patients with increased postoperative transfusion requirements or a PMH of either PE or renal insufficiency.

Preclinical evaluation of combined TKI-258 and RAD001 in hepatocellular carcinoma.

PURPOSE: RAD001 targets at the mammalian target of rapamycin (mTOR), while TKI-258 is a potent tyrosine kinase inhibitor targeting at fibroblast growth factor receptor, vascular endothelial growth factor receptor, platelet-derived growth factor receptor and c-kit. We aim to study the activity of combined RAD001 and TKI-258 in cell lines and xenograft model of hepatocellular carcinoma (HCC), with reference to the parallel and upstream pathways of Akt-mTOR axis. METHODS: A panel of 4 human HCC cell lines HepG2, Hep3B, PLC/PRF/5 and Huh7 and the Hep3B-derived xenograft were treated with TKI-258 or/and RAD001, respectively. Related mechanistic studies (including apoptosis and angiogenesis) were conducted. RESULTS: There was an enhanced increase in suppression of cell proliferation with combined TKI-258 and RAD001 compared with either drug alone. The combination could significantly suppress the phosphorylation of mTOR, MEK1/2 and p38 MAPK. Although the addition of the TKI258 only slightly suppressed the phosphorylation of AKT induced by RAD001, the pi-mTOR and its downstream signaling pathways including pi-p70S6K, pi-S6 and pi-4EBP1 were lowered in the combination. In Hep3B-derived xenograft, TKI-258 and RAD001 had shown an enhanced inhibition of tumor growth without impact on the weight of animals. There was a reduction in microvessel density in the xenograft with the combination, which indicated an enhanced inhibition on angiogenesis. Pro-caspases-3 and PARP cleavage were slightly detected at 48 h after treatment, suggesting that the combination mainly increased the cytostatic arrest ability. CONCLUSIONS: The combination of RAD001 and TKI-258 was active in HCC via inhibition of both mTOR-mediated signaling and its parallel pathways.

Enhanced Antitumor Activity with Combining Effect of mTOR Inhibition and Microtubule Stabilization in Hepatocellular Carcinoma.

Mammalian target of rapamycin (mTOR) and the microtubules are shown to be potential targets for treating hepatocellular carcinoma (HCC). PI3K/Akt/mTOR activation is associated with resistance to microtubule inhibitors. Here, we evaluated the antitumor activity by cotargeting of the mTOR (using allosteric mTOR inhibitor everolimus) and the microtubules (using novel microtubule-stabilizing agent patupilone) in HCC models. In vitro studies showed that either targeting mTOR signaling with everolimus or targeting microtubules with patupilone was able to suppress HCC cell growth in a dose-dependent manner. Cotargeting of the mTOR (by everolimus) and the microtubules (by patupilone, at low nM) resulted in enhanced growth inhibition in HCC cells (achieving maximal growth inhibition of 60-87%), demonstrating potent antitumor activity of this combination. In vivo studies showed that everolimus treatment alone for two weeks was able to inhibit the growth of Hep3B xenografts. Strikingly, the everolimus/patupilone combination induced a more significant antitumor activity. Mechanistic study demonstrated that this enhanced antitumor effect was accompanied by marked cell apoptosis induction and antiangiogenic activity, which were more significant than single-agent treatments. Our findings demonstrated that the everolimus/patupilone combination, which had potent antitumor activity, was a potential therapeutic strategy for HCC.

Preclinical evaluation of the AKT inhibitor MK-2206 in nasopharyngeal carcinoma cell lines.

Nasopharyngeal carcinoma (NPC) is endemic to Asia and over 40 % of NPC tissues harbor PIK3CA amplifications. This study characterized the preclinical activity of MK-2206, an oral allosteric inhibitor of AKT in 6 NPC cell lines: C666-1, HK1, HONE-1-EBV, HONE-1, CNE-2 and HNE-1. Exposure to increasing concentrations of MK-2206 resulted in over 95 % of growth inhibition in all NPC cell lines with IC50 values in the low micromolar range. Further experiments were performed in 3 representative NPC cell lines: CNE-2 (harbor PIK3CA mutation and most sensitive to MK-2206), C666-1 (carries PIK3CA amplification), and HONE-1-EBV (least sensitive to MK-2206). MK-2206 induced G0/G1 cycle arrest in all 3 cell lines, but could induce apoptosis only in CNE-2 cells. MK-2206 significantly abrogated AKT signaling in all 3 cell lines by inhibiting the activation of AKT and its downstream effectors (FKHR, GSK3ß and BAD). MK-2206 also reduced mTOR signaling by reducing activation of mTOR and its downstream 4E-BP1 and p70S6 kinase. MAPK activation was observed in HONE-1 and C666-1 cells, but not in CNE-2 cells following exposure to MK-2206. The addition of MK-2206 to cisplatin (but not with paclitaxel) has a supra-additive inhibitory effect on growth in vitro. In summary, MK-2206 can inhibit growth and abrogate AKT and mTOR signaling in NPC cell lines. This agent is currently being evaluated in a phase II study in metastatic NPC.

Activity of the MEK inhibitor selumetinib (AZD6244; ARRY-142886) in nasopharyngeal cancer cell lines.

This study evaluated the preclinical activity of selumetinib (AZD6244, ARRY-142866), an inhibitor of the mitogen-activated protein kinase kinase (MAPKK or MEK1/2) in 6 nasopharyngeal cancer (NPC) cell lines. Selumetinib could achieve up to 90 % inhibition of cell growth with the respective IC(50) values in NPC cell lines as follow: HK1 = 0.04 µM, HK1-LMP1(B95.8) = 0.17 µM, HONE-1-EBV = 0.46 µM, HONE-1 = 1.79 µM, CNE-2 = 2.20 µM and C666-1 > 10 µM. The drug-sensitive cell lines HK1, HK1-LMP1(B95.8) and HONE-1-EBV have higher basal expression of phosphorylated (pi)-MAPK than the less sensitive cell lines. BRAF mutations were not detected in all 6 cell lines. Re-introduction of the EBV genome into HONE-1 cells, generating the HONE-1-EBV cell line, seemed to result in elevated expression of pi-MAPK and sensitivity to selumetinib when compared with the parental HONE-1 cells. At a concentration of 0.5 µM and 5 µM, selumetinib induced apoptosis (as indicated by cleaved PARP expression and caspase 3 induction), and G(0)/G(1) cycle arrest in HONE-1-EBV and HK1-LMP1(B95.8) cells. The combination of selumetinib (at IC(25) concentration) and the EGFR tyrosine kinase inhibitor, gefitinib (at concentrations of 0.1, 3 and 9 µM) resulted in synergistic growth inhibition in HK1-LMP1(B95.8) cells. The combination of selumetinib (at IC(25) concentration) and cisplatin (at concentrations of 0.1, 0.4, 0.8 and 2 µM) resulted in synergistic growth inhibition in HONE-1 and HONE-1-EBV cells. This result suggests that selumetinib alone or in combination with gefitinib or cisplatin maybe a promising strategy against NPC. Further studies are warranted.

Sustained antitumor activity by co-targeting mTOR and the microtubule with temsirolimus/vinblastine combination in hepatocellular carcinoma.

The mammalian target of rapamycin (mTOR) and the microtubules are prominent druggable targets for hepatocellular carcinoma (HCC). PI3K/Akt/mTOR activation is associated with resistance to microtubule inhibitors. Here, we hypothesized that co-targeting of mTOR (by mTOR inhibitor temsirolimus) and the microtubule (by microtubule-destabilizing agent vinblastine) would be more efficacious than single targeting in HCC models. In vitro studies showed that effective inhibition of mTOR signaling with temsirolimus alone was able to suppress HCC cell growth in a dose-dependent manner. Among five cell lines tested, Huh7 was the most temsirolimus-sensitive (IC(50)=1.27±0.06µM), while Hep3B was the most temsirolimus-resistant (IC(50)=52.95±17.14µM). We found that co-targeting of mTOR (by temsirolimus) and the microtubule (by vinblastine, at low nM) resulted in marked growth inhibition in Huh7 cells and synergistic growth inhibition in Hep3B cells (achieving maximal growth inhibition of 80-90%), demonstrating potent antitumor activity of this novel combination. In vivo studies showed that temsirolimus treatment alone for 1 week was able to inhibit the growth of Huh7 xenografts. Strikingly, the temsirolimus/vinblastine combination induced a significant and sustained antitumor activity (up to 27 days post-treatment), with effective reduction of tumor vessel density in both Huh7 and Hep3B xenograft models. Mechanistic investigation revealed that this marked antitumor effect was accompanied by specific and concerted down-regulation of several key anti-apoptotic/survival proteins (survivin, Bcl-2, and Mcl-1), which was not observed in single agent treatments. Our findings demonstrated that the potent anti-cancer activity of this co-targeting strategy was indeed mediated in parts by inhibition of these key survival/anti-apoptotic proteins.

K252a induces anoikis-sensitization with suppression of cellular migration in Epstein-Barr virus (EBV)--associated nasopharyngeal carcinoma cells.

Recent studies revealed an unexpected role of the neurotrophin receptor pathway, BDNF/TrkB signaling, in cancer metastasis and anoikis (i.e. detachment-induced cell death). Survival of cancer cells in detached state (known as anoikis-resistance) is known to be pre-requisite for metastasis. Nasopharyngeal carcinoma (NPC), an endemic head and neck cancer in Southeast Asia, is highly invasive, metastatic, and etiologically associated with Epstein-Barr virus (EBV, an oncovirus) infection. Mechanistic studies on the invasive/metastatic nature of NPC can facilitate the development of anti-metastatic therapy in NPC. Thus far, the role of BDNF/TrkB signaling in virus-associated human cancer is unclear. Here, using multiple cell line models of NPC with EBV-association (HONE-1-EBV, HK1-LMP1 and C666-1), we investigated the potential involvement of BDNF/TrkB signaling in cellular migration and anoikis-resistant characteristics of NPC. We found that all three EBV-associated NPC cell lines tested were intrinsically anoikis-resistant (i.e. survived in detached state) and expressed both BDNF and TrkB. BDNF stimulation induced cellular migration, but not proliferation of these cells. Further, we examined if pharmacologic targeting of anoikis-resistance of NPC cells can be achievable by a proof-of-concept Trk inhibitor, K252a, in these EBV-associated NPC models. Our results demonstrated that K252a, was able to attenuate BDNF-induced migration and proliferation of NPC cells. More importantly, we demonstrated for the first time that K252a harbored potent anoikis-sensitization activity (i.e. sensitizing cancer cells to detachment-induced cell death) against EBV-associated human cancer cells, namely NPC cells. This proof-of-concept study demonstrated that K252a, a Trk inhibitor, can potentially be used as an anoikis-sensitizing agent in NPC.

Anti-invasion, anti-proliferation and anoikis-sensitization activities of lapatinib in nasopharyngeal carcinoma cells.

Nasopharyngeal cancer (NPC) is a highly prevalent and invasive head and neck cancer in Asia. Disease recurrence and distant metastasis account for major NPC deaths. Therefore, more effective therapy is needed. Lapatinib, a dual tyrosine kinase inhibitor (TKI) against both EGFR and HER-2, has been known to exert potent antitumor activity against several cancer models. Given that both EGFR and HER-2 are co-expressed in NPC, we hypothesized that dual targeting of EGFR and HER-2 by this small molecule EGFR/HER-2 TKI would elicit anti-tumor activity in NPC. Using in vitro models of NPC, we demonstrated that lapatinib was able to efficiently inhibit the phosphorylation of both EGFR and HER-2. This was accompanied by significant growth inhibition of NPC cells (with maximal growth inhibition >90%). For the most lapatinib-sensitive cell line (HK1-LMP1, with IC(50) ∼ 600 nM), which harbored the highest levels of both EGFR and HER-2, inhibition of cell growth was associated G(0)/G(1) cell cycle arrest, marked PARP cleavage, caspase-3 cleavage, as well as significant downregulation of several important survival proteins (e.g. survivin, Mcl-1 and cyclin D1). NPC cells are intrinsically invasive. We found that lapatinib was able to inhibit cellular invasion of both HK1-LMP1 and HONE-1 cells. Furthermore, our data demonstrated for the first time that lapatinib harbored potent anoikis-sensitization activity (i.e. sensitizing cancer cells to detachment-induced apoptosis) in human cancer cells overexpressing both EGFR and HER-2 (HK1-LMP1 and HK1). Taken together, our findings suggest that lapatinib is a promising anti-cancer agent for NPC with anti-invasion and anoikis-sensitization activities.

Preclinical evaluation of sunitinib as single agent or in combination with chemotherapy in nasopharyngeal carcinoma.

PURPOSE: Sunitinib is a multi-target receptor tyrosine kinase (RTK) inhibitor against vascular endothelial growth factor receptors, platelet-derived growth factor receptors (PDGFR), c-kit and RET. Several of these RTKs are known to be involved in the progression of nasopharyngeal carcinoma (NPC). Here, we evaluated the preclinical activities of sunitinib in NPC. METHOD: We determined the basal level of total and phosphorylated PDGFR, c-kit and RET by immunoblotting in a panel of five NPC cell lines. The effect of sunitinib on NPC cell proliferation was evaluated by MTT assay. We further studied the effect of sunitinib on NPC cell cycle progression and apoptosis. We investigated the in vitro and in vivo activities of sunitinib as single agent and in combination with cisplatin or docetaxel in NPC cell lines and tumor xenografts. RESULTS: Sunitinib exhibited dose-dependent growth inhibition in all NPC cell lines tested with IC(50) between 2-7.5 µM and maximum inhibition of over 97%. Sunitinib induced apoptosis and cell cycle arrest at G(0)/G(1) phase. In vitro, sunitinib moderately enhanced the growth inhibition of cisplatin or docetaxel. Single agent sunitinib demonstrated significant growth inhibition, reduced microvessel density and caused extensive tumor necrosis in a NPC xenograft model. However, concurrent administration of sunitinib and docetaxel induced severe toxicity in mice without enhanced antitumor effect. CONCLUSIONS: Single agent sunitinib demonstrated potent in vitro and in vivo growth inhibition in NPC. When combined with chemotherapy, sequential instead of concurrent administration schedule should be further explored.

An RNA-directed nucleoside anti-metabolite, 1-(3-C-ethynyl-beta-d-ribo-pentofuranosyl)cytosine (ECyd), elicits antitumor effect via TP53-induced Glycolysis and Apoptosis Regulator (TIGAR) downregulation.

1-(3-C-ethynyl-beta-d-ribo-pentofuranosyl)cytosine (ECyd) is a ribose-modified nucleoside analog of cytidine with potent anticancer activity in several cancers. The main antitumor mechanism of this promising RNA-directed nucleoside anti-metabolite is efficient blockade of RNA synthesis in cancer cells. Here, we examined the therapeutic potential of this RNA-directed anti-metabolite in in vitro models of nasopharyngeal cancer (NPC). In a panel of 6 NPC cell lines, ECyd effectively inhibited cellular proliferation at nM concentrations (IC(50): approximately 13-44nM). Moreover, cisplatin-resistant NPC cells were highly sensitive to ECyd (at nM concentration). The ECyd-mediated growth inhibition was associated with G(2)/M cell cycle arrest, PARP cleavage (a hallmark of apoptosis) and Bcl-2 downregulation, indicating induction of apoptosis by ECyd in NPC cells. Unexpectedly, ECyd-induced significant downregulation of TIGAR, a newly described dual regulator of apoptosis and glycolysis. More importantly, this novel action of ECyd on TIGAR was accompanied by marked depletion of NADPH, the major reducing power critically required for cell proliferation and survival. We hypothesized that ECyd-induced TIGAR downregulation was crucially involved in the antitumor activity of ECyd. Indeed, overexpression of TIGAR was able to rescue NPC cells from ECyd-induced growth inhibition, demonstrating a novel mechanistic action of ECyd on TIGAR. We demonstrated for the first time that an RNA-directed nucleoside analog, ECyd, exerts its antitumor activity via downregulation of a novel regulator of apoptosis, TIGAR. Moreover, ECyd may represent a novel therapy for NPC.