Phosphoinositide 3-kinase accelerates postoperative tumor growth by inhibiting apoptosis and enhancing resistance to chemotherapy-induced apoptosis. Novel role for an old enemy

Screening of factors inducing alveolar type 1 epithelial cells using human pluripotent stem cells

Alveolar type 2 (AT2) epithelial cells are tissue stem cells capable of differentiating into alveolar type 1 (AT1) cells for injury repair and maintenance of lung homeostasis. However, the factors involved in human AT2-to-AT1 cell differentiation are not fully understood. Here, we established SFTPCGFP and AGERmCherry-HiBiT dual-reporter induced pluripotent stem cells (iPSCs), which detected AT2-to-AT1 cell differentiation with high sensitivity and identified factors inducing AT1 cell differentiation from AT2 and their progenitor cells. We also established an "on-gel" alveolar epithelial spheroid culture suitable for medium-throughput screening. Among the 274 chemical compounds, several single compounds, including LATS-IN-1, converted AT1 cells from AT2 and their progenitor cells. Moreover, YAP/TAZ signaling activation and AKT signaling suppression synergistically recapitulated the induction of transcriptomic, morphological, and functionally mature AT1 cells. Our findings provide novel insights into human lung development and lung regenerative medicine.

Astragaloside IV combating liver cirrhosis through the PI3K/Akt/mTOR signaling pathway

Astragaloside IV (AS-IV) in improving liver cirrhosis injury in rats and its effect on the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mechanistic target of rapamycin (mTOR) signaling pathway were observed. Rat model of liver cirrhosis was induced by injection of carbon tetrachloride (CCl₄). A total of 36 Sprague-Dawley (SD) rats were randomly divided into three groups: the normal control group (n=10), the model control group (n=13), and the AS-IV group (n=13). The normal control group was injected with olive oil and given carboxymethyl cellulose (CMC)-Na (10 ml/kg/day), the model control group was given CMC-Na (10 ml/kg/day), and the AS-IV group underwent intragastric administration of AS-IV (20 ml/kg/day). The content of alanine transaminase (ALT) and aspartate transaminase (AST) of rats was detected. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β in serum were detected via enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (H&E) staining was applied to observe morphological changes in liver tissues. The expression of collagens in liver tissues was detected via Masson's trichrome staining. Additionally, the expression of proteins in liver tissues was detected via western blotting. Compared with those in the blank group, the levels of AST, ALT, TNF-α, IL-6 and IL-1β were higher, the expression level of collagens in liver tissues was increased, and the expression ratios of phosphorylated (p)-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR proteins were increased in the model group. Compared with the model group, AS-IV could significantly decrease the content of AST, ALT, TNF-α, IL-6 and IL-β in serum of rats, obviously inhibit the expression of collagens in liver tissues and decrease the expression ratios of p-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR proteins in liver tissues. AS-IV can inhibit the inflammatory response so as to reduce the expression of collagens, and its mechanism may play a key role by inhibiting the PI3K/Akt/mTOR signaling pathway.

Identification of protein kinase inhibitors to reprogram breast cancer cells

Direct reversion of cancers into normal-like tissues is an ideal strategy for cancer treatment. Recent reports have showed that defined transcription factors can induce reprogramming of cancer cells into pluripotent stem cells, supporting this notion. Here, we have developed a reprogramming method that uses a conceptually unique strategy for breast cancer cell treatment. We have screened a kinase inhibitor library and found that Rho-associated protein kinase (ROCK) and mammalian target of rapamycin (mTOR) kinase inhibitors can substitute for all transcription factors to be sufficient to reprogram breast cancer cells into progenitor cells. Furthermore, ROCK–mTOR inhibitors could reprogram breast cancer cells to another terminal lineage-adipogenic cells. Genome-wide transcriptional analysis shows that the induced fat-like cells have a profile different from breast cancer cells and similar to that of normal adipocytes. In vitro and in vivo tumorigenesis assays have shown that induced fat-like cells lose proliferation and tumorigenicity. Moreover, reprogramming treatment with ROCK–mTOR inhibitors prevents breast cancer local recurrence in mice. Currently, ROCK–mTOR inhibitors are already used as antitumor drugs in patients, thus, this reprogramming strategy has significant potential to move rapidly toward clinical trials for breast cancer treatment.

RandomiSed clinical trial assessing Use of an anti-inflammatoRy aGent in attenUating peri-operatiVe inflAmmatioN in non-meTastatic colon cancer - the S.U.R.G.U.V.A.N.T. trial

Background

Peri-operative inflammation has been extensively highlighted in cancer patients as detrimental. Treatment strategies to improve survival for cancer patients through targeting peri-operative inflammation have yet to be devised.

Methods

We conducted a multi-centre, randomised controlled clinical trial using Taurolidine in non-metastatic colon cancer patients. Patients were randomly assigned to receive Taurolidine or a placebo. The primary endpoint for the study was the mean difference in day 1 IL-6 levels. Secondary clinical endpoints included rates of post-operative infections and tumor recurrence.

Results

A total of 293 patients were screened for trial inclusion. Sixty patients were randomised. Twenty-eight patients were randomised to placebo and 32 patients to Taurolidine. IL-6 levels were equivalent on day 1 post-operatively in both groups. However, IL-6 levels were significantly attenuated over the 7 day study period in the Taurolidine group compared to placebo (p = 0.04). In addition, IL-6 levels were significantly lower at day 7 in the Taurolidine group (p = 0.04). There were 2 recurrences in the placebo group at 2 years and 1 in the Taurolidine group. The median time to recurrence was 19 months in the Placebo group and 38 months in the Taurolidine group (p = 0.27). Surgical site infection was reduced in the Taurolidine treated group (p = 0.09).

Conclusion

Peri-operative use of Taurolidine significantly attenuated circulating IL-6 levels in the initial 7 day post-operative period in a safe manner. Future studies are required to establish the impact of IL-6 attenuation on survival outcomes in colon cancer.

Trial registration

The trial was registered with EudraCT (year = 2008, registration number = 005570–12) and ISRCTN (year = 2008, registration number = 77,829,558).

Anti-apoptosis Effect of Decoy Receptor 3 in Cholangiocarcinoma Cell Line TFK-1

Background:

Decoy receptor 3 (DcR3) is a protein with anti-apoptotic effect that belongs to the tumor necrosis factor receptor superfamily. DcR3 is highly expressed in a variety of malignant tumors including cholangiocarcinoma and its expression was found to be related to the clinical stage, the invasion, and the metastasis of the tumor. This in vitro study aimed to investigate the effect of downregulated expression of DcR3 on cell viability, cell apoptosis, and cell cycle in cholangiocarcinoma cell line TFK-1.

Methods:

Three different cell lines were cultured: human cholangiocarcinoma TFK-1, human biliary epithelial carcinoma HuCCT-1, and human cholangiocarcinoma RBE. The cholangiocarcinoma cell line with the highest expression of DcR3 was selected for further investigation. The expression of DcR3 was silenced/knocked down by transfection with DcR3-siRNA in the selected cell line. Various biological phenotype parameters such as cell viability, apoptosis, and cell cycle were observed.

Results:

The mRNA and protein levels of DcR3 were measured in the three cell lines, and TFK-1 was selected. After the treatment with DcR3-siRNA for 48 h, DcR3 mRNA and protein expression in the treatment group were 38.45% (P < 0.01) and 48.03% (P < 0.05) of that of the control, respectively. It was found that the cell viability decreased to 61.87% of the control group (P < 0.01) after the downregulation of DcR3 in cholangiocarcinoma cell line TFK-1 by transfection with DcR3-siRNA, while the percentage of apoptotic cells was 2.98 times as compared with the control group (P < 0.05). Compared with the control group the ratio of G₀/G₁ increased, and the ratio of G₂/M decreased in the treatment group. However, the differences were not statistically significant.

Conclusions:

The effect of DcR3 on the growth and apoptosis of cholangiocarcinoma has been demonstrated. DcR3 is not only a predictive marker for malignant tumor but it is also likely to be a potential target for cancer gene therapy. Further studies should focus on exploring the binding ligand of DcR3, the signaling pathway involved, and the molecular mechanism for the regulation of DcR3 expression in cholangiocarcinoma.

Postoperative anti-PD-1 antibody treatment to reduce recurrence in a cancer ablation surgical wound

BACKGROUND

Postoperative radiation and chemotherapy are routinely applied for microscopic residual diseases; however, treatment outcomes are not optimal, and patients frequently suffer from treatment-related toxicities. To search for an effective and less-toxic adjuvant treatment for patients with high risk of recurrence, the preventive effect of anti-programmed cell death protein 1 (PD-1) treatment was evaluated in an in vivo animal model of post-surgical tumor recurrence.

MATERIALS AND METHODS

An animal model of postsurgical tumor recurrence (SCCVII tumors in C3H mice) was established by reinoculating tumor cells (10⁵ cells) into surgical wound of primary tumor resection. Initial and recurrent tumors were compared by an immunohistochemistry and complementary DNA microarray. Using this in vivo model, tumor recurrence rates were evaluated in the animals receiving anti-PD-1 treatments. Animals were rechallenged with tumor cells, and interferon gamma secretion from spleen cells was analyzed to determine tumor-specific antitumor immunity.

RESULTS

FoxP3^high cell population was significantly elevated in recurrent tumors compared with that in primary tumors. Some immune response-related factors (granzyme F, neuronal leucine-rich repeat protein 1, myosin heavy chain 3, and transmembrane protein 8C) showed significant differences between primary and recurrent tumors. In this animal model, anti-PD-1 treatments significantly suppressed tumor recurrence. Importantly, tumor induction was significantly reduced when anti-PD-1-treated mice were rechallenged with tumor cells. Tumor cell-specific interferon gamma production was increased in these animals.

CONCLUSIONS

Postoperative anti-PD-1 treatment significantly reduced recurrence in a cancer ablation surgical wound in an in vivo model of tumor recurrence. Our data lay the preclinical groundwork for the future clinical validation of adjuvant anti-PD-1 treatments in patients.

BAY 1125976, a selective allosteric AKT1/2 inhibitor, exhibits high efficacy on AKT signaling-dependent tumor growth in mouse models

The PI3K-AKT-mTOR signaling cascade is activated in the majority of human cancers, and its activation also plays a key role in resistance to chemo and targeted therapeutics. In particular, in both breast and prostate cancer, increased AKT pathway activity is associated with cancer progression, treatment resistance and poor disease outcome. Here, we evaluated the activity of a novel allosteric AKT1/2 inhibitor, BAY 1125976, in biochemical, cellular mechanistic, functional and in vivo efficacy studies in a variety of tumor models. In in vitro kinase activity assays, BAY 1125976 potently and selectively inhibited the activity of full-length AKT1 and AKT2 by binding into an allosteric binding pocket formed by kinase and PH domain. In accordance with this proposed allosteric binding mode, BAY 1125976 bound to inactive AKT1 and inhibited T308 phosphorylation by PDK1, while the activity of truncated AKT proteins lacking the pleckstrin homology domain was not inhibited. In vitro, BAY 1125976 inhibited cell proliferation in a broad panel of human cancer cell lines. Particularly high activity was observed in breast and prostate cancer cell lines expressing estrogen or androgen receptors. Furthermore, BAY 1125976 exhibited strong in vivo efficacy in both cell line and patient-derived xenograft models such as the KPL4 breast cancer model (PIK3CA^H1074R mutant), the MCF7 and HBCx-2 breast cancer models and the AKT^E17K mutant driven prostate cancer (LAPC-4) and anal cancer (AXF 984) models. These findings indicate that BAY 1125976 is a potent and highly selective allosteric AKT1/2 inhibitor that targets tumors displaying PI3K/AKT/mTOR pathway activation, providing opportunities for the clinical development of new, effective treatments.

Suppression of Asparaginyl Endopeptidase Inhibits Polyomavirus Middle T Antigen-Induced Tumor Formation and Metastasis

Elevated circulating asparaginyl endopeptidase (AEP), a novel lysosomal protease, has been found in breast cancer, and AEP is thus considered to be a prognostic factor in this disease. However, the pathological functions of circulating AEP in the development of breast cancer and the potential of AEP-targeted therapy remain unclear. We used MMTV-PyVmT transgenic mice, which spontaneously develop mammary tumors. Western blotting showed overexpression of AEP in both primary tumor tissue and lung metastases compared to their normal counterparts. Moreover, the concentration of circulating AEP gradually increased in the serum during the development of mammary tumors. Purified AEP protein injected through the tail vein promoted tumor growth and mammary tumor metastasis and shortened survival, whereas AEP-specific small compound inhibitors (AEPIs) effectively suppressed tumor progression and prolonged host survival. Further analysis of the molecular mechanism revealed that AEP was important for PI3K/AKT pathway activation. Thus, an elevated serum AEP level was closely related to mammary cancer progression and metastasis, and AEP is a potential target for breast cancer therapy in the clinic.

Mechanosensitive caveolin-1 activation-induced PI3K/Akt/mTOR signaling pathway promotes breast cancer motility, invadopodia formation and metastasis in vivo

Cancer cells are subjected to fluid shear stress during passage through the venous and lymphatic system. Caveolin-1 (Cav-1), a principal structural component of caveolar membrane domains, contributes to cancer development but its mechanobiological roles under low shear stress (LSS) conditions remain largely unknown. Here, we identified Cav-1 is mechanosensitive to LSS exposure, and its activation-induced PI3K/Akt/mTOR signaling promotes motility, invadopodia formation and metastasis of breast carcinoma MDA-MB-231 cells. Application of LSS (1.8 and 4.0 dynes/cm2) to MDA-MB-231 cells significantly increased the cell motility, invadopodia formation, MT1-MMP expression, ECM degradation, and also induced a sustained activation of Cav-1 and PI3K/Akt/mTOR signaling cascades. Methyl-β-cyclodextrin-caused caveolae destruction markedly decreased LSS-induced activation of both Cav-1 and PI3K/Akt/mTOR, leading to suppress MT1-MMP expression, inhibit invadopodia formation and ECM degradation, suggesting that caveolae integrity also involved in metastasis. Immunocytochemical assay showed that LSS induces the Cav-1 clustering in lipid rafts and co-localization of Cav-1 and MT1-MMP on invadopodia. Immunofluorescence confocal analysis demonstrated that Cav-1 activation were required for the acquisition of a polarized phenotype in MDA-MB-231 cells. Finally, Cav-1 knockdown significantly suppressed tumor colonization in the lungs and distant metastases in animal models. Our findings highlight the importance of Cav-1 in hematogenous metastasis, and provide new insights into the underlying mechanisms of mechanotransduction induced by LSS.

Icariin enhances cytotoxicity of doxorubicin in human multidrug-resistant osteosarcoma cells by inhibition of ABCB1 and down-regulation of the PI3K/Akt pathway

Multidrug resistance is one of the major causes limiting the efficacy of chemotherapeutic agents used to control osteosarcoma. Multidrug resistance protein 1 (MDR1 or ABCB1) was considered to play a critical role in multidrug resistance. Agents from traditional Chinese medicines (TCMs) have great potential to prevent the onset or delay the progression of the carcinogenic process, and also to enhance the efficacy of mainstream antitumor agents. Herein, we investigated the effect and mechanism of icariin in the human osteosarcoma doxorubicin (DOX)-resistant cell line MG-63/DOX. In this study, icariin exhibited significant effects in sensitization of the resistant cancer cells at a concentration non-toxic to doxorubicin. It also increased the intracellular doxorubicin accumulation and retention in MG-63/DOX cells. In addition, an increase in Rh123 accumulation and a decrease in Rh123 efflux were observed in MG-63/DOX cells treated with icariin, indicating a blockage of the activity of MDR1. Furthermore, icariin enhanced the apoptosis induced by doxorubicin and down-regulated the expression of MDR1. The mechanism involves the inhibition of phosphatidyl inositol 3-kinase (PI3K)/Akt signaling. In conclusion, icariin possesses a reversal effect on multidrug resistance in MG-63/DOX cells through down-regulation of the MDR1 and the PI3K/Akt pathway, and has the potential to be an adjunct to chemotherapy for osteosarcoma.

RABEX-5 is upregulated and plays an oncogenic role in gastric cancer development by activating the VEGF signaling pathway

RABEX-5, a guanine-nucleotide exchange factor (GEF) for RAB-5, is implicated in tumorigenesis and in the development of certain human cancers. Here, we report that RABEX-5 promotes tumor growth and the metastatic ability of gastric cancer cells both in vitro and in vivo. Expression of RABEX-5 is significantly higher in gastric cancer tissues and is associated with tumor size and lymph node metastasis. In addition, targeted silencing of RABEX-5 reduced gastric cancer cell proliferation and colony formation in vitro via the induction of a G0/G1 phase arrest, and stimulated gastric cancer cell apoptosis. Knockdown of RABEX-5 also inhibited wound healing, migration and the invasive abilities of gastric cancer cells. The results of in vivo animal experiments were also consistent with these in vitro findings. Silencing of RABEX-5 led to decreased expression of VEGF. These results indicate that RABEX-5 is upregulated and plays an oncogenic role in gastric cancer development by activating the VEGF signaling pathway.

The role of focal adhesion kinase in the regulation of cellular mechanical properties

The regulation of mechanical properties is necessary for cell invasion into connective tissue or intra- and extravasation through the endothelium of blood or lymph vessels. Cell invasion is important for the regulation of many healthy processes such as immune response reactions and wound healing. In addition, cell invasion plays a role in disease-related processes such as tumor metastasis and autoimmune responses. Until now the role of focal adhesion kinase (FAK) in regulating mechanical properties of cells and its impact on cell invasion efficiency is still not well known. Thus, this review focuses on mechanical properties regulated by FAK in comparison to the mechano-regulating protein vinculin. Moreover, it points out the connection between cancer cell invasion and metastasis and FAK by showing that FAK regulates cellular mechanical properties required for cellular motility. Furthermore, it sheds light on the indirect interaction of FAK with vinculin by binding to paxillin, which then impairs the binding of paxillin to vinculin. In addition, this review emphasizes whether FAK fulfills regulatory functions similar to vinculin. In particular, it discusses the differences and the similarities between FAK and vinculin in regulating the biomechanical properties of cells. Finally, this paper highlights that both focal adhesion proteins, vinculin and FAK, synergize their functions to regulate the mechanical properties of cells such as stiffness and contractile forces. Subsequently, these mechanical properties determine cellular invasiveness into tissues and provide a source sink for future drug developments to inhibit excessive cell invasion and hence, metastases formation.

BAY 80-6946 is a highly selective intravenous PI3K inhibitor with potent p110α and p110δ activities in tumor cell lines and xenograft models

Because of the complexity derived from the existence of various phosphoinositide 3-kinase (PI3K) isoforms and their differential roles in cancers, development of PI3K inhibitors with differential pharmacologic and pharmacokinetic profiles would allow best exploration in different indications, combinations, and dosing regimens. Here, we report BAY 80-6946, a highly selective and potent pan-class I PI3K inhibitor with sub-nanomolar IC50s against PI3Kα and PI3Kδ. BAY 80-6946 exhibited preferential inhibition (about 10-fold) of AKT phosphorylation by PI3Kα compared with PI3Kβ in cells. BAY 80-6946 showed superior antitumor activity (>40-fold) in PIK3CA mutant and/or HER2 overexpression as compared with HER2-negative and wild-type PIK3CA breast cancer cell lines. In addition, BAY 80-6946 revealed potent activity to induce apoptosis in a subset of tumor cells with aberrant activation of PI3K as a single agent. In vivo, single intravenous administration of BAY 80-6946 exhibited higher exposure and prolonged inhibition of pAKT levels in tumors versus plasma. BAY 80-6946 is efficacious in tumors with activated PI3K when dosed either continuously or intermittently. Thus, BAY 80-6946 induced 100% complete tumor regression when dosed as a single agent every second day in rats bearing HER2-amplified and PIK3CA-mutated KPL4 breast tumors. In combination with paclitaxel, weekly dosing of BAY 80-6946 is sufficient to reach sustained response in all animals bearing patient-derived non-small cell lung cancer xenografts, despite a short plasma elimination half-life (1 hour) in mice. Thus, BAY 80-6946 is a promising agent with differential pharmacologic and pharmacokinetic properties for the treatment of PI3K-dependent human tumors.

Jolkinolide B induces apoptosis in MCF-7 cells through inhibition of the PI3K/Akt/mTOR signaling pathway

The aim of this study was to explore the molecular mechanisms of jolkinolide B (JB), which is extracted from the root of Euphorbia fischeriana Steud. In this study, we found that JB, a diterpenoid from the traditional Chinese medicinal herb, strongly inhibited the PI3K/Akt/mTOR signaling pathway. Furthermore, we evaluated the effects of JB on the proliferation and apoptosis of MCF-7 human breast cancer cells. Our results showed significant induction of apoptosis in MCF-7 cells incubated with JB. The viability of the MCF-7 cells was assessed by MTT assay. Flow cytometry was used to detect apoptosis and cell cycle analysis. Transmission electron microscopy (TEM) analysis was used to observe cell morphology. MCF-7 cells were subcutaneously inoculated into nude mice to study the in vivo antitumor effects of JB. The growth of MCF-7 cells was inhibited and arrested in the S phase by JB. The data showed significantly decreased tumor volume and weight in nude mice inoculated with MCF-7 cells. In addition, treatment with JB was able to induce downregulation of cyclinD1, cyclinE, mTOR, p-PI3K and p-Akt, and upregulation of PTEN and p-eIF4E. Collectively, JB-induced apoptosis of MCF-7 cells occurs through the PI3K/Akt/mTOR signaling pathway. Furthermore, the PI3K/Akt signaling cascade plays a role in the induction of apoptosis in JB-treated cells. These observations suggest that JB may have therapeutic applications in the treatment of cancer.

[The study of PI3K/AKT pathway in lung cancer metastasis and drug resistance]

磷脂酰肌醇-3-激酶/丝苏氨酸蛋白激酶（phosphatidyl-inositol 3-kinase/serine-threonine kinase, PI3K/ AKT）信号通路是细胞内重要信号转导通路之一，通过影响下游多种效应分子的活化状态，在细胞内发挥抑制凋亡、促进增殖的关键作用，与人类多种肿瘤的发生发展密切相关。研究表明PI3K/AKT信号通路在恶性肿瘤细胞的增殖、血管新生和转移及对放化疗的拮抗中都起着重要作用。对PI3K/AKT信号通路的深入研究有望找到肿瘤预防和药物治疗的新靶点。本文简要介绍了PI3K/AKT信号通路的组成与功能调节，并着重阐述了其在肺癌转移和耐药中的作用。

Surgical injury enhances the expression of genes that mediate breast cancer metastasis to the lung

OBJECTIVE

This study was conducted to test the hypothesis that surgery induces changes at the expression level of genes implicated in metastasis, thus leading to accelerated postoperative metastatic tumor growth.

SUMMARY BACKGROUND DATA

Surgical resection of the primary tumor is a necessary and effective treatment for breast cancer patients. However, studies from both animals and humans have shown that surgery potentiates the growth of minimal residual neoplastic disease.

METHODS

: Female BALB/c mice were inoculated with metastatic murine mammary adenocarcinoma 4T1-green fluorescent protein (GFP) cells in the mammary fat pad (3 × 10⁵/mouse), and divided into a surgery group (n = 12) in which the flank tumor was completely resected after 21 day growth and a control (no surgery) group (n = 12). Metastatic tumor burden was assessed by both macroscopic metastatic nodule count and clonogenic assay. Mitotic and apoptotic indices were established using a combination of hematoxylin-eosin histology and Ki-67 immunohistochemistry. Green fluorescent protein (GFP) expressing tumor cells were isolated using FACS sorting, and RNA was extracted. The RT² Profiler PCR Array mouse Cancer Pathway Finder was used to determine and compare the mRNA levels of 84 genes involved in metastasis in both groups.

RESULTS

Excision of the primary tumor was associated with increased systemic metastatic burden (P = 0.001). Postoperative metastases exhibited increased proliferation (P = 0.001), but no reduction in apoptosis. The quantitative real-time polymerase chain reaction array data indicate that surgery significantly upregulated the expression of Itgb3, Egfr, Hgf, Igf1, Pdgfb, Tnfα, Vegfa, Vegfc, and MMP9 genes, and led to the down regulation of Cdkn2a, Cdh1, and Syk genes. Increased expression of ITGB3 and MMP9 was further confirmed at the protein level by Western blot.

CONCLUSIONS

Removal of the primary tumor led to a progressive phenotype of lung metastases that exhibited upregulation of genes involved in adhesion, invasion, and angiogenesis.

Adipose-derived mesenchymal stem cells as stable source of tumor necrosis factor-related apoptosis-inducing ligand delivery for cancer therapy

Adipose-derived mesenchymal stromal/stem cells (AD-MSC) may offer efficient tools for cell-based gene therapy approaches. In this study, we evaluated whether AD-MSC could deliver proapoptotic molecules for cancer treatment. Human AD-MSCs were isolated and transduced with a retroviral vector encoding full-length human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a proapoptotic ligand that induces apoptosis in a variety of human cancers but not normal tissues. Although several studies have documented the antitumor activity of recombinant human TRAIL, its use in vivo is limited by a short half-life in plasma due to a rapid clearance by the kidney. We found that these limitations can be overcome using stably transduced AD-MSC, which could serve as a constant source of TRAIL production. AD-MSC armed with TRAIL targeted a variety of tumor cell lines in vitro, including human cervical carcinoma, pancreatic cancer, colon cancer, and, in combination with bortezomib, TRAIL-resistant breast cancer cells. Killing activity was associated with activation of caspase-8 as expected. When injected i.v. or s.c. into mice, AD-MSC armed with TRAIL localized into tumors and mediated apoptosis without significant apparent toxicities to normal tissues. Collectively, our results provide preclinical support for a model of TRAIL-based cancer therapy relying on the use of adipose-derived mesenchymal progenitors as cellular vectors.

Increased mRNA expression of epidermal growth factor receptor, human epidermal receptor, and survivin in human gastric cancer after the surgical stress of laparotomy versus carbon dioxide pneumoperitoneum in a murine model

BACKGROUND

Surgical impact may be associated with enhanced tumor growth and chemoresistance. This study aimed to evaluate the effect of surgical impact on the mRNA expression of survivin, epidermal growth factor receptor (EGFR), and human epidermal receptor (HER2) in tumors after pneumoperitoneum versus laparotomy.

METHODS

Nude mice were inoculated intraperitoneally with human gastric cancer cells (MKN45). Then laparotomy, carbon dioxide (CO(2)) pneumoperitoneum, and anesthesia alone were performed randomly, after which EGFR, HER2, and survivin mRNA expression using reverse transcription-polymerase chain reaction (RT-PCR) was evaluated.

RESULTS

The expression of EGFR and HER2 mRNA increased significantly after the experiment. However, it was higher after laparotomy than after CO(2) pneumoperitoneum at almost all examined time points. Survivin mRNA expression increased significantly in the first 48 h, then returned to the control level. It was higher after laparotomy than after CO(2) pneumoperitoneum 48 h after the surgical procedures.

CONCLUSION

The expression of EGFR, HER2, and survivin increased after each surgical procedure. However it was lower after CO(2) pneumoperitoneum than after laparotomy. This might be associated with changes in the chemosensitivity of the remnant cancer cells after surgery, supporting the use of minimally invasive surgery for cancer.

The perioperative period is an underutilized window of therapeutic opportunity in patients with colorectal cancer

OBJECTIVE

In this review, we address the underlying mechanisms by which surgery augments metastases outgrowth and how these insights can be used to develop perioperative therapeutic strategies for prevention of tumor recurrence.

SUMMARY BACKGROUND DATA

Surgical removal of the primary tumor provides the best chance of long-term disease-free survival for patients with colorectal cancer (CRC). Unfortunately, a significant part of CRC patients will develop metastases, even after successful resection of the primary tumor. Paradoxically, it is now becoming clear that surgery itself contributes to development of both local recurrences and distant metastases.

METHODS

Data for this review were identified by searches of PubMed and references from relevant articles using the search terms "surgery," "CRC," and "metastases."

RESULTS

Surgical trauma and concomitant wound-healing processes induce local and systemic changes, including impairment of tissue integrity and production of inflammatory mediators and angiogenic factors. This can lead to immune suppression and enhanced growth or adhesion of tumor cells, all of which increase the chance of exfoliated tumor cells developing into secondary malignancies.

CONCLUSIONS

Because surgery remains the appropriate and necessary means of treatment for most CRC patients, new adjuvant therapeutic strategies that prevent tumor recurrence after surgery need to be explored since the perioperative therapeutic window of opportunity offers promising means of improving patient outcome but is unfortunately underutilized.

Integrin α6 induces PI3K and MAPK signal pathway in the adhesion of hepatocellular carcinoma

AIM: To investigate the changes of signal pathways in the adhesion of hepatocellular carcinoma with extracellular matrix.

METHODS: BEL-7402 cells were cultured regularly on media containing laminin (LN) or bovine serum albumin (BSA, served as control matrix). After treatment with anti-integrin α6 monoclonal antibody, cell changes and integrin α6-induced signal pathways were observed. Boyden chamber was used to detect cell migration and invasion ability. Western blot was adopted to analyze the phosphorylation of ERK. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to measure the expression of PI3K and Akt mRNA.

RESULTS: BEL-7402 cells adhered to different extracellular matrices within 30 min to 1 h without significance. The rate of cell adhesion on LN-coated substrate was 187.2%, but decreased to 104.4% after anti-integrinα6 monoclonal antibody treatment (P < 0.05). The number of BEL-7402 cells migrated through the Matrigel was 103.2 ± 16.5 per high power field (HPF), and anti-integrin α6 monoclonal antibody inhibited it to 88.7 ± 9.9 (P < 0.01). The expression levels of PI3K and Akt were up-regulated, and phosphorylation of ERK was increased after BEL-7402 cell adhered to LN; however, anti-integrin α6 monoclonal antibody partly inhibited the up-regulation and phosphorylation.

CONCLUSION: Cultured BEL-7402 cells highly express integrin α6. PI3K and ERK pathway is involved in the adhesion associated with LN and integrin α6.

Evolving management of colorectal cancer

This article reviews recent advances in surgical techniques and adjuvant therapies for colorectal cancer, including total mesorectal excision, the resection of liver and lung metastasis and advances in chemoradiation and foreshadows some interventions that may lie just beyond the frontier. In particular, little is known about the intracellular and extracellular cascades that may influence colorectal cancer cell adhesion and metastasis. Although the phosphorylation of focal adhesion kinases and focal adhesion associated proteins in response to integrin-mediated cell matrix binding (”outside in integrin signaling”) is well described, the stimulation of cell adhesion by intracellular signals activated by pressure prior to adhesion represents a different signal paradigm. However, several studies have suggested that increased pressure and shear stress activate cancer cell adhesion. Further studies of the pathways that regulate integrin-driven cancer cell adhesion may identify ways to disrupt these signals or block integrin-mediated adhesion so that adhesion and eventual metastasis can be prevented in the future.

A comprehensive analysis of transcript signatures of the phosphatidylinositol-3 kinase/protein kinase B signal-transduction pathway in prostate cancer

OBJECTIVE

To assess the gene activities of various important members of the phosphatidylinositol 3 kinase (PIK3)/protein kinase B (PKB/Akt) pathway (involved in the promotion and regulation of cellular metabolism, proliferation and apoptosis) for alterations in prostate carcinoma.

PATIENTS, SUBJECTS AND METHODS

Using quantitative real-time reverse-transcription polymerase chain reaction, we analysed the transcript levels of 12 genes involved in the PIK3/PKB pathway in microdissected tumour tissues from 20 patients with varying stages of prostate cancer, assessing differences from adjacent normal tissues and from a pool of prostate tissues from healthy controls.

RESULTS

In cancer samples with a high Gleason grade, the PIK3/PKB pathway was principally affected by marked decreases in expression over almost all the investigated stages of the pathway. These changes were in effectors of the pathway, especially PIK3 p85 alpha (PIK3R1) and integrin-linked kinase, and the pathway target fork-head box protein (FOXO)-1A, while the transcript quantities of regulators, e.g. phosphatase/tensin homologue (PTEN), were decreased in a smaller proportion of the patients. Transcript amounts of FOXO-1A and FOXO-3A were significantly higher in normal tumour-adjacent tissues than in the healthy controls.

CONCLUSIONS

Down-regulation of the PIK3/PKB pathway by repression of involved effector and regulator genes at all stages of the molecular pathway could represent a marker for the formation of highly de-differentiated prostate cancers from low-grade tumour foci. Also, parts of the pathway are deviant in normal tumour-adjacent tissue; this might represent a reaction to neighbouring tumours or be a sign of pre-cancerous biological alterations.

Blocking alpha2 integrins on rat CC531s colon carcinoma cells prevents operation-induced augmentation of liver metastases outgrowth

Currently, an operation is the only curative option for patients with colorectal cancer. Unfortunately, many patients will develop liver metastases even after successful resection of the primary tumor. Removal of primary colorectal carcinoma may paradoxically increase the risk of metastases development, because accumulating evidence suggests that surgical trauma can stimulate tumor growth. In the present study, we investigated the effects of abdominal trauma on liver metastases development. Surgical trauma dramatically increased adhesion of tumor cells in the liver, leading to enhanced outgrowth of metastases. Endothelial stress was observed rapidly after an operation, suggesting that abdominal trauma resulted in impairment of blood vessel integrity. Tumor cells preferentially adhered to extracellular matrix (ECM). Furthermore, preincubation of tumor cells with anti-alpha2 integrin antibodies completely reverted operation-induced augmentation of CC531s adhesion and liver metastases outgrowth. As such, we postulate that blood vessel integrity in the liver is compromised after abdominal trauma, resulting in enhanced ECM exposure, which enables tumor cell adhesion and metastases outgrowth.

CONCLUSION

Perioperative treatments that either aim to reduce endothelial stress or block the interaction between tumor cells and ECM represent promising new therapeutic strategies for the prevention of liver metastases development after resection of the primary tumor.

Mapping genes that contribute to daunorubicin-induced cytotoxicity

Daunorubicin is an anthracycline antibiotic agent used in the treatment of hematopoietic malignancies. Toxicities associated with this agent include myelosuppression and cardiotoxicity; however, the genes or genetic determinants that contribute to these toxicities are unknown. We present an unbiased genome-wide approach that incorporates heritability, whole-genome linkage analysis, and linkage-directed association to uncover genetic variants contributing to the sensitivity to daunorubicin-induced cytotoxicity. Cell growth inhibition in 324 Centre d' Etude du Polymorphisme Humain lymphoblastoid cell lines (24 pedigrees) was evaluated following treatment with daunorubicin for 72 h. Heritability analysis showed a significant genetic component contributing to the cytotoxic phenotypes (h2 = 0.18-0.63 at 0.0125, 0.025, 0.05, 0.1, 0.2, and 1.0 mumol/L daunorubicin and at the IC50, the dose required to inhibit 50% cell growth). Whole-genome linkage scans at all drug concentrations and IC50 uncovered 11 regions with moderate peak LOD scores (> 1.5), including 4q28.2 to 4q32.3 with a maximum LOD score of 3.18. The quantitative transmission disequilibrium tests were done using 31,312 high-frequency single-nucleotide polymorphisms (SNP) located in the 1 LOD confidence interval of these 11 regions. Thirty genes were identified as significantly associated with daunorubicin-induced cytotoxicity (P < or = 2.0 x 10(-4), false discovery rate < or = 0.1). Pathway and functional gene ontology analysis showed that these genes were overrepresented in the phosphatidylinositol signaling system, axon guidance pathway, and GPI-anchored proteins family. Our findings suggest that a proportion of susceptibility to daunorubicin-induced cytotoxicity may be controlled by genetic determinants and that analysis using linkage-directed association studies with dense SNP markers can be used to identify the genetic variants contributing to cytotoxicity.

Tolerization with BLP down-regulates HMGB1-a critical mediator of sepsis-related lethality

Tolerization with bacterial lipoprotein (BLP) affords a significant survival benefit in sepsis. Given that high mobility group box protein-1 (HMGB1) is a recognized mediator of sepsis-related lethality, we determined if tolerization with BLP leads to alterations in HMGB1. In vitro, BLP tolerization led to a reduction in HMGB1 gene transcription. This was mirrored at the protein level, as HMGB1 protein expression and release were reduced significantly in BLP-tolerized human THP-1 monocytic cells. BLP tolerance in vivo led to a highly significant, long-term survival benefit following challenge with lethal dose BLP in C57BL/6 mice. This was associated with an attenuation of HMGB1 release into the circulation, as evidenced by negligible serum HMGB1 levels in BLP-tolerized mice. Moreover, HMGB1 levels in peritoneal macrophages from BLP-tolerized mice were reduced significantly. Hence, tolerization with BLP leads to a down-regulation of HMGB1 protein synthesis and release. The improved survival associated with BLP tolerance could thus be explained by a reduction in HMGB1, were the latter associated with lethality in BLP-related sepsis. In testing this hypothesis, it was noted that neutralization of HMGB1, using anti-HMGB1 antibodies, abrogated BLP-associated lethality almost completely. To conclude, tolerization with BLP leads to a down-regulation of HMGB1, thus offering a novel means of targeting the latter. HMGB1 is also a mediator of lethality in BLP-related sepsis.

Membrane expression of DR4, DR5 and caspase-8 levels, but not Mcl-1, determine sensitivity of human myeloma cells to Apo2L/TRAIL

The improved recombinant form of the death ligand Apo2L/TRAIL (Apo2L/TRAIL.0) is not cytotoxic for normal human cells and is a good candidate for the therapy of multiple myeloma (MM), a B-cell neoplasia that remains incurable. We have analyzed the molecular determinants of myeloma sensitivity to Apo2L/TRAIL.0 in a number of MM cell lines, the mechanisms of resistance and a possible way of overcoming it. Expression of one death receptor for Apo2L/TRAIL (DR4 or DR5) is sufficient to transduce death signals, though DR5 was more efficient when both receptors were present. Membrane expression of decoy receptors (DcR1, DcR2) and intracellular levels of c-FLIP(L), XIAP and Mcl-1 were not predictive of resistance to Apo2L/TRAIL. Inhibition of Mcl-1 degradation did not prevent Apo2L/TRAIL-induced apoptosis. In IM-9 cells, resistance was associated to a reduced caspase-8 expression. U266 cells, though expressing significant levels of DR4 and caspase-8, were nevertheless resistant to Apo2L/TRAIL. This resistance could be overcome by co-treatment with valproic acid (VPA), a histone deacetylase inhibitor. VPA caused the redistribution of DR4 to plasma membrane lipid rafts and restored DR4 signaling. Overexpression of Mcl-1 in U266 cells did not prevent Apo2L/TRAIL cytotoxicity in VPA-sensitized cells. These results, taken together, support the possible use of Apo2L/TRAIL.0 in the treatment of MM.

Characterization of the Effects of Cyclooxygenase-2 Inhibition in the Regulation of Apoptosis in Human Small and Non–Small Cell Lung Cancer Cell Lines

BACKGROUND

Cyclooxygenase-2 enzyme (COX-2) is overexpressed in human non-small cell lung cancer (NSCLC) but is not expressed in small cell lung cancer. Selective COX-2 inhibitors have been shown to induce apoptosis in NSCLC cells, an effect which is associated with the regulation of intracellular MAP kinase (MAPK) signal pathways. Our aims were to characterize the effects of COX-2 inhibition by rofecoxib on apoptosis in human NSCLC and small cell lung cancer cell lines.

METHODS

The human NSCLC cell line NCI-H2126 and small cell lung cancer cell line DMS-79 were used. Constitutive COX-2 protein levels were first determined by Western blot test. Levels of apoptosis were evaluated by using propidium iodide staining on FACScan analysis after incubation of NCI-H2126 and DMS-79 with p38 MAPK inhibitor SB202190 (25 ?microM), NF-kappaB inhibitor SN50 (75 microg/mL), and rofecoxib at 100 and 250 microM. All statistical analysis was performed by analysis of variance.

RESULTS

Western blot test confirmed the presence of COX-2 enzyme in NCI-H2126 and absence in DMS-79. Interestingly, rofecoxib treatment demonstrated a dose-dependent increase in apoptosis in both cell lines. Given this finding, the effect of rofecoxib on NF-kappaB and p38 MAPK pathways was also examined. Apoptosis in both cell lines was unaltered by SN50, either alone or in combination with rofecoxib. A similar phenomenon was observed in NCI-H2126 cells treated with SB202190, either alone or in combination with rofecoxib. In contrast, p38 MAPK inhibition greatly upregulated DMS-79 apoptosis in a manner that was unaltered by the addition of rofecoxib.

CONCLUSIONS

Rofecoxib led to a dose-dependent increase in apoptosis in both tumor cell lines. This effect occurred independently of COX-2, NF-kappaB, and p38 MAPK pathways in DMS-79 cells. As such, rofecoxib must act on alternative pathways to regulate apoptosis in human small cell lung cancer cells.

FAK association with multiple signal proteins mediates pressure-induced colon cancer cell adhesion via a Src-dependent PI3K/Akt pathway

Cancer cell adhesion is traditionally viewed as random, occurring if the cell's receptors match the substrate. Cancer cells are subjected to pressure and shear during growth against a constraining stroma, surgical manipulation, and passage through the venous and lymphatic system. Cells shed into a cavity such as the abdomen postoperatively also experience increased pressure from postoperative edema. Increased extracellular pressure stimulates integrin-mediated cancer cell adhesion via FAK and Src. PI 3-kinase (PI3K) inhibitors (LY294002 or wortmannin), Akt inhibitors, or Akt1 siRNA blocked adhesion stimulated by 15 mmHg pressure in SW620 or primary human malignant colonocytes. Pressure activated PI3K, tyrosine-phosphorylated and membrane-translocated the p85 subunit, and phosphorylated Akt. PI3K inhibitor (LY294002) prevented pressure-stimulated Akt Ser473 and FAK Tyr397, but not FAK576 or Src416 phosphorylation. PP2 inhibited PI3K activity and Akt phosphorylation. FAK siRNA did not affect pressure-induced PI3K activation but blocked Akt phosphorylation. Pressure also stimulated FAK or FAKY397F mutant translocation to the membrane. Akt inhibitor IV blocked pressure-induced Akt and FAK translocation. Pressure activated Src- and PI3K-dependently induced p85 interaction with FAK, and FAK with beta1 integrin. These results delineate a novel force-activated inside-out Src/PI3K/FAK/Akt pathway by which cancer cells regulate their own adhesion. These signals may be potential targets for inhibition of metastatic adhesion.

The targeting of phosphoinositide-3 kinase attenuates pulmonary metastatic tumor growth following laparotomy

OBJECTIVE

We aimed to characterize a potential role for phosphatidylinositol 3-kinase (PI3k) in leading to accelerated postoperative metastatic tumor growth.

BACKGROUND

PI3k enhances tumor cell survival in part by phosphorylating Akt and reducing apoptosis. Postoperatively, apoptosis is reduced within local recurrences and distant metastases. This reduction is associated with the phenomenon of accelerated postoperative tumor growth.

METHODS

Balb/c mice underwent a tail vein injection of 1x10 metastatic murine mammary adenocarcinoma 4T1 cells. Animals were divided into the following treatment groups (n=10/group): group A, controls; group B, DMSO intraperitoneally (IP) daily from days 14 to 21; group C, IP LY294002 daily from days 14 to 21; group D, laparotomy only; group E, laparotomy followed by IP DMSO for 7 days; and group F, laparotomy followed by LY294002 IP for 7 days. All laparotomies were performed on day 14. Animals were killed at day 28. Metastatic tumor burden was assessed using the lung/body weight ratio and a histologic metastatic index. Mitotic counts and apoptotic indices were established using a combination of hematoxylin and eosin histology and TUNEL immunohistochemistry. A parallel survival study was performed, and PI3k activity was assessed using western blots for phospho-Akt.

RESULTS

Laparotomy was associated with increased systemic tumor burden (P=0.001). Postoperatively, LY294002 significantly attenuated metastatic tumor growth (P<0.001). Effective PI3k inhibition was confirmed by demonstrating a reduced Akt phosphorylation. Moreover, PI3k inhibition led to reduced proliferation, increased apoptosis (P<0.001), and enhanced postoperative survival (P<0.001).

CONCLUSIONS

Targeting PI3k with postoperative LY294002 significantly attenuates the acceleration in postoperative metastatic tumor growth seen following laparotomy.

Cancer surgery: risks and opportunities

In the recent past, several papers have pointed to the possibility that tumour removal generates a permissive environment in which tumour growth is potentiated. This phenomenon has been coined "perioperative tumour growth" and whilst it represents a departure in terms of our attitude to the surgical process, this concept was first hinted at by Paget(1) himself. Despite this, the time interval immediately before and after cancer surgery (i.e. the perioperative period) remains an underutilised interval during which chemotherapeutic regimens are rarely implemented. Herein, we present a summarised review of the literature that supports the concept that tumour removal may potentiate the growth of residual neoplastic disease. We also outline current knowledge regarding underlying mechanisms and in this manner highlight potential therapeutic entry points. Finally, we emphasise the urgent need for trials of agents that could protect patients against the harmful host-tumour interactions that may occur during the perioperative period.