Improved therapeutic efficacy against murine carcinoma by combining honokiol with gene therapy of PNAS-4, a novel pro-apoptotic gene

PNAS-4, a novel pro-apoptotic gene activated during the early response to DNA damage, can inhibit proliferation via apoptosis when overexpressed in some tumor cells. Recent studies have indicated that honokiol can induce apoptosis, inhibit angiogenesis, and suppress tumor growth. In the present study, we investigated whether mouse PNAS-4 (mPNAS-4) could augment the apoptosis of tumor cells induced by honokiol in vitro, and whether the antiangiogenic activity of honokiol and induction of apoptosis by mPNAS-4 could work cooperatively to improve the antitumor efficacy in vivo. In vitro , mPNAS-4 inhibited proliferation of murine colorectal carcinoma CT26 and Lewis lung carcinoma LL2 cells through induction of apoptosis, and significantly augmented the apoptosis of CT26 and LL2 cells induced by honokiol. Compared with treatment with mPNAS-4 or honokiol alone, in vivo systemic administration of an expression plasmid encoding mPNAS-4 and low-dose honokiol significantly suppressed tumor growth through the enhanced induction of apoptosis and the augmented inhibition of angiogenesis. Our data suggest that the combined treatment with mPNAS-4 plus honokiol augments antitumor effects in vitro and in vivo , and that the improved antitumor activity in vivo may be associated with enhanced induction of apoptosis and augmented inhibition of angiogenesis. The present study may provide a novel and effective method for the treatment of cancer. ( Cancer Sci 2009; 100: 1757–1766)     

TLR3 as a biomarker for the therapeutic efficacy of double-stranded RNA in breast cancer

The discovery of a targeted therapeutic compound along with its companion predictive biomarker is a major goal of clinical development for a personalized anticancer therapy to date. Here we present evidence of the predictive value of TLR3 expression by tumor cells for the efficacy of Poly (A:U) dsRNA in 194 breast cancer patients enrolled in a randomized clinical trial. Adjuvant treatment with double-stranded RNA (dsRNA) was associated with a significant decrease in the risk of metastatic relapse in TLR3 positive but not in TLR3-negative breast cancers. Moreover, we show the functional relevance of TLR3 expression by human tumor cells for the antitumor effects mediated by dsRNA in several preclinical mouse models carried out in immunocompromised animals. These 2 independent lines of evidence relied upon the generation of a novel tool, an anti-TLR3 antibody (40F9.6) validated for routine detection of TLR3 expression on paraffin-embedded tissues. Altogether, these data suggest that dsRNA mediates its therapeutic effect through TLR3 expressed on tumor cells, and could therefore represent an effective targeted treatment in patients with TLR3-positive cancers.     

Exosome targeting of tumor antigens expressed by cancer vaccines can improve antigen immunogenicity and therapeutic efficacy

MVA-BN-PRO (BN ImmunoTherapeutics) is a candidate immunotherapy product for the treatment of prostate cancer. It encodes 2 tumor-associated antigens, prostate-specific antigen (PSA), and prostatic acid phosphatase (PAP), and is derived from the highly attenuated modified vaccinia Ankara (MVA) virus stock known as MVA-BN. Past work has shown that the immunogenicity of antigens can be improved by targeting their localization to exosomes, which are small, 50- to 100-nm diameter vesicles secreted by most cell types. Exosome targeting is achieved by fusing the antigen to the C1C2 domain of the lactadherin protein. To test whether exosome targeting would improve the immunogenicity of PSA and PAP, 2 additional versions of MVA-BN-PRO were produced, targeting either PSA (MVA-BN-PSA-C1C2) or PAP (MVA-BN-PAP-C1C2) to exosomes, while leaving the second transgene untargeted. Treatment of mice with MVA-BN-PAP-C1C2 led to a striking increase in the immune response against PAP. Anti-PAP antibody titers developed more rapidly and reached levels that were 10- to 100-fold higher than those for mice treated with MVA-BN-PRO. Furthermore, treatment with MVA-BN-PAP-C1C2 increased the frequency of PAP-specific T cells 5-fold compared with mice treated with MVA-BN-PRO. These improvements translated into a greater frequency of tumor rejection in a PAP-expressing solid tumor model. Likewise, treatment with MVA-BN-PSA-C1C2 increased the antigenicity of PSA compared with treatment with MVA-BN-PRO and resulted in a trend of improved antitumor efficacy in a PSA-expressing tumor model. These experiments confirm that targeting antigen localization to exosomes is a viable approach for improving the therapeutic potential of MVA-BN-PRO in humans.     

Enhanced therapeutic efficacy of cisplatin by combination with diethyldithiocarbamate and hyperthermia in a mouse model

A spontaneously metastasizing solid tumor model derived by transplanting the TA3Ha murine mammary carcinoma into the s.c. tail tissue of mice was used to develop a treatment strategy for enhancing the therapeutic efficacy of cisplatin (CDDP). This strategy was based on the findings that diethyldithiocarbamate (DDTC) reduces the toxicity of CDDP, and that localized hyperthermia (HT) augments the antitumor efficacy of CDDP. DDTC (500 mg/kg) reduced the CDDP-induced nephrotoxicity and gastrointestinal toxicity as well as increased the CDDP LD10 from 8 to 20 mg/kg in strain A mice. When CDDP and DDTC were used in multiple treatment schedules at 5-day intervals, DDTC protected the hosts but not the tumors against the toxicity of CDDP. HT administered locally to the tumor 1 h after the injection of CDDP (8 mg/kg) in 1 ml Hanks' balanced salt solution increased the antitumor effect but not the host toxicity. While administration of 8 mg/kg CDDP alone or with HT three times at 5-day intervals caused 100% host mortality, this dose of CDDP could be used with no mortality by combining it with DDTC. A combination of 8 mg/kg CDDP with DDTC (750 mg/kg) and HT (43 degree C for 60 min), administered three times at 5-day intervals, retarded the local tumor growth significantly compared to the untreated, CDDP plus DDTC plus HT control groups of mice. The frequency of lung metastasis in these groups on day 30 of tumor inoculation were 0, 90, 90, and 80%, respectively. The mean survival days of the mice treated with CDDP plus DDTC plus HT was 61 +/- 6 compared to 34 +/- 5 in the controls. The results presented here demonstrate that by combining CDDP with DDTC, high doses of CDDP can be safely administered. When localized HT is combined with high dose CDDP and DDTC, the tumor growth retardation and the host survival prolongation are significantly better than those obtained with the highest tolerable dose of CDDP alone or CDDP plus HT.     

Systemic cancer therapy with a small molecule agonist of toll-like receptor 7 can be improved by circumventing TLR tolerance

Topical application of small molecule Toll-like receptor 7 (TLR7) agonists is highly effective for the treatment of skin tumors, whereas their systemic application has been largely unsuccessful for cancer therapy. One reason may be that repeated systemic application of TLR ligands can induce a state of immune unresponsiveness, termed TLR tolerance. We show here that a single injection of the TLR7 agonist R848 in mice induces a short period of increased response to TLR stimulation followed by a state of hyporesponsiveness lasting several days. This state is characterized by inhibited secretion of the key cytokines interleukin (IL)-12p70 and IL-6 as well as by a block in IFN-α production. We show for the first time that at the cellular level, TLR7 tolerance occurs in both plasmacytoid and myeloid dendritic cells, two cell populations that play a critical role in the initiation and amplification of antitumor immune responses. We further show that TLR7 tolerance in plasmacytoid dendritic cells is accompanied by downregulation of the adaptor protein IL-1 receptor-associated kinase 1. On the basis of these findings, we have designed a novel strategy for the treatment of tumors by using cycles of repeated R848 injections separated by treatment-free intervals. We show in CT26 tumor-bearing mice that this protocol circumvents TLR7 tolerance and improves the efficacy of cancer immunotherapy.     

Midkine, a heparin-binding growth factor, produced by the host enhances metastasis of Lewis lung carcinoma cells

Midkine is a heparin-binding growth factor and is expressed by a number of tumor cells, contributing to their growth both in vitro and in vivo. Spontaneous lung metastasis of Lewis lung carcinoma cells, which did not significantly express MK, was significantly less extensive in mice deficient in the midkine gene than in wild-type mice, when the tumor was subcutaneously grown above the thigh. Midkine strongly enhanced migration of Lewis lung carcinoma cells in vitro. Therefore, midkine is also a host factor enhancing tumor metastasis. Anti-midkine therapy for malignancy may act on midkine produced by both the tumor and host.     

Induction of interleukin 3 and tumor resistance by SSM, a cancer immunotherapeutic agent extracted from Mycobacterium tuberculosis

Interleukin 3 (IL-3) activity was demonstrated when inguinal lymph node cells obtained from Bacillus Calmette-Guérin-sensitized mice (BCG-ILNC) were stimulated in vitro with SSM, an immunomodulator extracted from Mycobacterium tuberculosis. The IL-3 activity was first detected on Day 1 in culture fluids of BCG-ILNC stimulated with SSM, reached a peak on Day 3, and then gradually decreased. The activity was completely neutralized by treatment with anti-murine IL-3 monoclonal antibody (mAb). When BCG-ILNC were treated with anti-Thy 1.2 or anti-Lyt 1.2 mAb followed by complement, IL-3 was not produced in the culture fluids. However, IL-3 in the culture fluids was detected when BCG-ILNC were treated with anti-Lyt 2.2 mAb, anti-asialo-GM1, or anti-mouse immunoglobulin antiserum followed by complement. These results suggested that Lyt 1+ T-cells appeared to be required for the production of IL-3 from BCG-ILNC stimulated with SSM. In addition, low but significant IL-3 activity was also observed in sera of mice treated with SSM. However, serum IL-3 activity was not detected in mice treated with both SSM and Thy 1.2 or Lyt 1.2 mAb, whereas the activity was induced by SSM in mice treated with anti-Lyt 2.2 mAb or anti-asialo-GM1 antiserum. On the other hand, the in vivo growth of IMC tumors inoculated in BALB/c x DBA/2 F1 mice was significantly decreased by intralesional injection of culture fluids containing IL-3, as well as by SSM itself. This antitumor activity of the culture fluids was not altered when it was treated with mAbs for interleukin 1, interleukin 2, or anti-mouse gamma-interferon antiserum. The antitumor activity of the fluid was only eliminated when it was treated with anti-mouse IL-3 mAb. Since nonspecific resistance to tumors in mice stimulated with SSM appears to require Lyt 1+ T-cells, these results suggest that, in part, nonspecific resistance to tumors of mice stimulated with SSM may be developed through IL-3, which was produced by Lyt 1+ T-cells after SSM stimulation.     

Improved safety, pharmacokinetics and therapeutic efficacy profiles of a novel liposomal formulation of mitoxantrone

We describe here the preclinical studies of a novel formulation of liposome-entrapped mitoxantrone (LEM). The liposome entrapment efficiency of mitoxantrone was 93.4 +/- 2.8%. In vitro cytotoxicity studies in HL60 cells comparing LEM with conventional mitoxantrone (MTO) showed IC50 values of 0.31 +/- 0.05 ng/ml and 0.48 +/- 0.06 ng/ml for LEM and MTO, respectively. In CD2F1 mice, LEM was significantly less toxic as compared with MTO. A single intravenous (i.v.) dose of 15 mg/kg MTO produced 100% mortality in CD2F1 mice by Day 10, whereas a single i.v. dose as high as 35 mg/kg LEM caused no mortality for at least up to Day 60 post-treatment. Multiple doses of MTO (i.v., 5.0 mg/kg, 1x daily, x5) caused 100% mortality by Day 10, whereas a similar dose regimen of LEM caused no mortality in CD2F1 mice. Clinical and histopathology evaluations indicated long-term normal tissue protection in mice treated with relatively high single dose (i.v., 35 mg/kg) or multiple doses of LEM (i.v., 5.0 mg/kg, 1x daily, x5). LEM also demonstrated favourable pharmacokinetic profiles. CD2F1 mice injected with 5 mg/kg i.v. dose of LEM showed plasma levels 51-fold higher than with an equivalent dose of MTO. The area under the plasma concentration-time curve was 200-fold greater with LEM as compared to MTO. The plasma half-lives were 0.96 hours and 0.11 hours for LEM and MTO, respectively. An altered tissue distribution was observed with LEM; cardiac tissue demonstrating at least 2.6-fold lower levels of mitoxantrone with LEM vs. MTO. LEM exhibited significant anti-tumor activity against murine ascitic L1210 leukemia in CD2F1 mice. Treatment with a single dose of 20.0 mg/kg LEM resulted in 100% long-term survivors. LEM 2.5 mg/kg (i.v., x4) had antitumor activity against a human hormone-independent prostate carcinoma (PC-3) grown in athymic mice, while a comparable dose of MTO was too toxic. A significant decrease in toxicity, altered pharmacokinetics, and enhanced efficacy of LEM suggest that LEM may provide a viable alternative to the clinical use of conventional mitoxantrone.     

Intratracheal and oral administration of SM‐276001: A selective TLR7 agonist,leads to antitumor efficacy in primary and metastatic models of cancer

Topical TLR7 agonists such as imiquimod are highly effective for the treatment of dermatological malignancies; however, their efficacy in the treatment of nondermatological tumors has been less successful. We report that oral administration of the novel TLR7‐selective small molecule agonist; SM‐276001, leads to the induction of an inflammatory cytokine and chemokine milieu and to the activation of a diverse population of immune effector cells including T and B lymphocytes, NK and NKT cells. Oral administration of SM‐276001 leads to the induction of IFNα, TNFα and IL‐12p40 and a reduction in tumor burden in the Balb/c syngeneic Renca and CT26 models. Using the OV2944‐HM‐1 model of ovarian cancer which spontaneously metastasizes to the lungs following subcutaneous implantation, we evaluated the efficacy of intratracheal and oral administration of SM‐276001 in an adjuvant setting following surgical resection of the primary tumor. We show that both oral and intratracheal TLR7 therapy can reduce the frequency of pulmonary metastasis, and metastasis to the axillary lymph nodes. These results demonstrate that SM‐276001 is a potent selective TLR7 agonist that can induce antitumor immune responses when dosed either intratracheally or orally.     

Enhanced and reversed growth In vivo of a pregnancy-dependent mouse mammary tumor (TPDMT-4) by a Gonadotropin-releasing hormone agonist analog

TPDMT-4 pregnancy-dependent mammary tumors grow continuously in DDD female mice carrying pituitary isografts (PI) ectopically or bearing an s.c. 17β-estradiol plus progesterone (EP) pellet. A gonadotropin-releasing hormone (GnRH) agonist, (d-leucyl⁶, des-glycyl-NH₂¹⁰, prolyl-ethylamide⁹) GnRH (TAP-144), was examined for its antitumor activity in these experimental systems. TAP-144 was injected i.p. at doses of 300 and 600 μg 6 times weekly, when tumors grew to significant sizes. TAP-144 enhanced tumor growth during the first 2 weeks and subsequently reversed it in a dose-related manner in PI-bearing mice. The agonist did not affect tumor growth in the absence of ovaries in these mice. In ovariectomized mice, TAP-144 enhanced EP pellet-induced tumor growth but never reversed it. In ovariectomized, PI-bearing mice, TAP-144 first enhanced and subsequently reversed tumor regrowth induced by ovarian grafts to a greater extent when commencing it simultaneously with ovarian grafting than 30 days before it. The agonist also exerted the dual effects on TPDMT-4V ovarian-dependent subline tumors in the absence of PI. In TAP-144-treated mice, enhanced tumor growth was related to many solid corpora lutea in ovaries and fully developed mammary glands, but reversed growth was related to atrophied luteal components and mammary glands. The results suggest that TAP-144 enhances tumor growth first via its stimulative action on the pituitary—ovarian axis and causes tumor regression later via its direct inhibitory action on ovaries.     

结核分枝杆菌感染的肺癌患者血清中lncRNA CCAT2、miR-20a的表达及其临床意义

目的:检测结核分枝杆菌（MTB）感染肺癌患者血清结肠癌相关转录因子2（lncRNA CCAT2）、miR-20a的表达,分析其临床意义。方法:选取2013年6月至2015年1月本院收治的肺癌患者104例为研究对象,其中MTB感染患者54例,未感染患者50例,同期选取本院健康体检者55例为对照组;实时荧光定量PCR（qRT-PCR）检测所有受试者血清lncRNA CCAT2、miR-20a表达水平;并对所有肺癌患者进行5年内随访,记录患者生存状态;Kaplan-Meier生存曲线分析lncRNA CCAT2、miR-20a与MTB感染肺癌患者及非MTB感染肺癌患者预后的关系;COX回归分析肺癌患者预后的危险因素。结果:与对照组比较,肺癌患者血清lncRNA CCAT2、miR-20a表达水平均显著升高（P＜0.05）,与非MTB感染肺癌患者比较,MTB感染患者lncRNA CCAT2、miR-20a表达水平均显著升高（P＜0.05）;肺癌患者血清lncRNA CCAT2和miR-20a表达与患者MTB感染、临床分期及组织分级有关;多因素COX分析表明,MTB感染、临床分期、组织分级、血清lncRNA CCAT2、miR-20a表达水平是影响肺癌患者预后的危险因素（P＜0.05）;对肺癌患者出院后随访,MTB感染患者和非MTB感染患者lncRNA CCAT2高表达组5年内生存率（12.9%、17.9%）均低于低表达组（21.7%、36.4%）,miR-20a高表达组5年内生存率（13.8%、18.5%）均低于低表达组（20.0%、34.8%）,MTB感染肺癌患者累积生存率（16.7%）低于非MTB感染肺癌患者（26.0%）。结论:lncRNA CCAT2、miR-20a可能参与MTB感染肺癌患者的预后,可能是MTB感染肺癌患者预后的生物标志物。     

MAGE-D4B is a novel marker of poor prognosis and potential therapeutic target involved in breast cancer tumorigenesis

Melanoma-associated antigen (MAGE) family members are generally described as tumor-specific antigens. An association between MAGE-D4B and breast cancer has yet to be reported and the functional role of the encoded protein has never been established. We performed microarray analysis of 104 invasive breast tumors and matched non-cancerous breast biopsies. qPCR was used for validation in an independent biobank. To investigate the biological relevance of MAGE-D4B in breast tumorigenesis, its phenotypic effects were assessed in vitro. Overall, MAGE-D4B was detected in 43% of tumors while undetected in normal breast tissue. MAGE-D4B was found to correlate with tumor progression and to be an independent prognostic marker for poor outcome in term of relapse-free and overall survival, with potential predictive relevance in relation to response to chemotherapy. RNA interference-mediated knockdown of MAGE-D4B significantly hampered the invasive properties of Hs578T cells by affecting anchorage-independent growth, adhesion, migration and invasion affecting anchorage-independent growth, adhesion, migration and invasion and by modulating expression of invasion-suppressor gene E-cadherin.     

Potentiation of etoposide-induced apoptosis in HeLa cells by co-treatment with KG-135, a quality-controlled standardized ginsenoside formulation

Our previous studies demonstrated that KG-135, a quality-controlled red ginseng-specific formulation containing approximately equal amounts of three major ginsenosides (Rk1, Rg3 and Rg5), down-regulated G1 cyclin-dependent kinase in HeLa cells. In the present work, we have found that KG-135 potentates cytotoxicity of etoposide by modulating apoptotic signaling. Co-treatment of etoposide and KG-135 markedly elevated the expression and phosphorylation at the serine 15 residue of p53 as well as the cellular levels of Bax and p21^Waf1/Cip1. The increased accumulation and phosphorylation of p53 (Ser15) were attenuated by treatment of cells with wortmannin, a pan-phosphatidylinositol-3 kinase inhibitor. Moreover, co-treatment of etoposide and KG-135 enhanced mitochondrial localization of Bax. Our results indicate that etoposide-induced apoptosis in HeLa cells can be potentiated in the presence of KG-135 through a mechanism that involves the stabilization of p53 and the stimulation of Bax- and p21-mediated apoptotic signaling pathways. These findings suggest that KG-135 represents a useful candidate adjuvant for the treatment of cancers that could potentially minimize the adverse effects of current clinical chemotherapeutics.     

Comparison of the therapeutic efficacy of 188Rhenium-liposomes and liposomal doxorubicin in a 4T1 murine orthotopic breast cancer model

Liposomal doxorubicin (Lipo-DOX) has been widely and successfully used in chemotherapy for breast cancer patients. Since our previous studies found that 188Rhenium (188Re)-N,N-bis (2-mercaptoethyl)-N',N'-diethy-lethylenediamine (BMEDA)-labeled pegylated liposomes (188Re-liposomes) have radiotherapeutic potential in a colon cancer model, and little information is available to make a comparison of the therapeutic efficacy of internal radiotherapy and chemotherapy, this study evaluates the therapeutic efficacy of 188Re-liposomes and Lipo-DOX, in a 4T1 murine orthotopic breast cancer model. MicroSPECT/CT imaging showed that the highest uptake of 188Re-liposomes was found at 24 h after intravenous administration. The results of a bio-distribution assay also demonstrated that the highest uptake of 188Re-liposomes in a tumor was 3.03±0.29 (%ID/g) at 24 h, and that the highest tumor to muscle ratio was approximately 17 at 48 h. According to measurements of body weight and survival rate, the maximum tolerated doses (MTD) of 188Re-liposomes and Lipo-DOX were 37 MBq and 25 mg/kg, respectively. In a study of therapeutic efficacy, mice with 4T1 orthotopic breast tumors that were treated with 188Re-liposomes (4/5 MTD, 29.6 MBq) or Lipo-DOX (4/5 MTD, 20 mg/kg), showed a significant inhibition of tumor growth. In the small tumor model (50 mm3), the lifespan of 4T1 tumor-bearing mice treated with 188Re-liposomes and Lipo-DOX was increased by 21.7 and 169.6%, respectively, compared to those treated with normal saline. In the large tumor model (300 mm3), the lifespan of the 188Re-liposomes and the Lipo-DOX treated group was also increased by 35.2 and 141.2%, respectively. In this study, it was found that Lipo-DOX is better than 188Re-liposomes, for the treatment of 4T1 breast cancer. A further investigation of combined therapy, in a breast cancer model, using 188Re-liposomes and Lipo-Dox, to determine whether a synergistic effect exists, is ongoing in our laboratory.     

Interleukin 18 gene transfer expands the repertoire of antitumor Th1-type immunity elicited by dendritic cell-based vaccines in association with enhanced therapeutic efficacy

Dendritic cells (DCs) are potent antigen-presenting cells that can prime and boost systemic antitumor immunity. Here, we have evaluated the ability of DCs transfected to secrete the potent Th1-biasing cytokine interleukin (IL)-18 to promote enhanced antitumor immunity in a mouse sarcoma model. DCs infected with a recombinant adenovirus encoding IL-18 (AdIL18DC) expressed higher levels of MHC and costimulatory molecules and were better stimulators than control DCs in mixed leukocyte reactions in vitro. Immunization of BALB/c mice bearing established day 7 CMS4 tumors with tumor peptide-pulsed control Adpsi5-transfected DCs or nontransduced DCs significantly inhibited the growth of established tumors but did not lead to complete regression of established tumors. Importantly, immunization with antigen-loaded AdIL18DC resulted in tumor rejection or further suppression of tumor growth when compared with controls. The repertoire of naturally presented tumor peptides recognized by splenocytes (as deduced in IFN-gamma ELISA assays) from AdIL18DC-treated animals was far more diverse and of greater magnitude than that of all other groups, in association with improved therapeutic outcome. These results support the ability of IL-18 gene transfer to enhance the capacity of DCs to drive broadly reactive Th1-type therapeutic immunity prompted by single peptide epitope-based vaccines (i.e., epitope spreading).     

Experimental therapy for colon cancer: anti-cancer effects of TLR9 agonism, combination with other therapeutic modalities, and dependence upon p53

The present study demonstrates the efficacy of utilizing TLR9 (toll-like receptor 9) agonism as a potential therapy for colon cancer. We examined the effects of two types of TLR9 agonists: a traditional CpG oligonucleotide and a novel immunomodulatory oligonucleotide in models of colon cancer, both alone and in combination with conventional cancer therapies. Because the tumor suppressor p53 is involved in many anti-cancer pathways, and is mutated in more than 50% of cancers, we determined whether p53 is necessary for the anti-tumor effects observed following treatment with TLR9 agonists. We also established that colon cancer cells express TLR9, which has not been demonstrated previously. The effects of TLR9 agonism on the growth, proliferation and apoptosis of colon cancer cells in vitro was then examined. We report five major discoveries: i) TLR9 agonism results in significant activity in models of colon cancer, ii) TLR9 agonists increase the anti-tumor effects of radiation and chemotherapy, iii) p53 is not required for the anti-cancer effects of TLR9 agonism, iv) human colon cancer cells express TLR9, and v) TLR9 agonism leads to decreased cell survival and proliferation and induces apoptosis of colon cancer cells in vitro. These results provide a basis for future studies determining the potential of utilizing TLR9 agonists for human colon cancer therapy.     

Inhibition of cell proliferation through cell cycle arrest and apoptosis by thio-Cl-IB-MECA, a novel A3 adenosine receptor agonist, in human lung cancer cells

Human A₃ adenosine receptor (A₃AR) agonists showed the anti-tumor activity in various in vitro and in vivo studies. The present study investigates the anti-proliferative effect of a novel adenosine analog 2-chloro-N⁶-(3-iodobenzyl)-4′-thioadenosine-5′-N-methyluronamide (thio-Cl-IB-MECA) in A549 human lung cancer cells. Thio-Cl-IB-MECA induced arrest of cell cycle progression in G0/G1 phase at lower concentrations (up to 20 μM) and apoptotic cell death at a higher concentration (80 μM), which were manifested by down-regulation of cyclin D1, c-myc, and CDK4, activation of caspase-3 and -9, and cleavage of poly(ADP-ribose) polymerase (PARP). The activation of Akt-mediated signaling was also inhibited by treatment with thio-Cl-IB-MECA. These data might suggest the potential therapeutic value of an adenosine analog in the treatment of human lung cancer.     

Hypothyroidism as a potential biomarker of efficacy of famitinib,a novel VEGFR-2 inhibitor in metastatic breast cancer

Purpose

Hypothyroidism is a common adverse event in patients treated with anti-VEGFR-2 targeting agents and may be a valuable predictive factor of efficacy. Famitinib is an inhibitor of multiple tyrosine kinases mainly targeting VEGFR-2. The objectives of this study were to assess the efficacy and safety of famitinib in patients with pretreated HER2-negative metastatic breast cancer (MBC) and to explore potential of famitinib-induced hypothyroidism and serum vascular endothelial growth factor (VEGF) level for efficacy prediction.

Materials and methods

The primary end point was objective response rate (ORR). Famitinib was administered 25 mg/d. Thyroid function assessments were done at baseline and then every 4 weeks. Plasma levels of VEGF were determined at baseline and 2 cycles after treatment.

Results

A total of 28 patients were enrolled. ORR was 14.3 %. The most common grade 3/4 AEs were hand–foot syndrome (25.0 %), proteinuria (21.4 %) and hypertension (17.9 %). 64.0 % patients were observed with elevated thyroid-stimulating hormone (TSH) (>4.94 mIU/L) at any time during the entire treatment period. Sixteen patients with an elevated TSH had a significantly longer PFS than nine patients with no TSH elevation (107 vs. 53 days, respectively, P = 0.002). TSH elevation was also an independent predictor of PFS in a Cox regression model. Plasma VEGF levels did not correlate significantly with clinical outcomes.

Conclusions

Famitinib did show substantial anti-tumor activities with a good safety profile in heavily pretreated patients with HER2-negative MBC. Famitinib-related TSH increase may be an early indicator of its efficacy. Serial monitoring of serum TSH may help define VEGFR-2-dependent or VEGFR-2-independent drug resistance.