midostaurin and Adenocarcinoma

PKC412 is a kinase inhibitor that blocks protein kinase C (PKC), vascular endothelial growth factor receptors, platelet-derived growth factor receptor FLT3, and other class III receptor tyrosine kinases. The enthusiasm for this compound is based on its inhibitory effect even in the case of FLT3 mutations. The aim of this study was to analyze the role of FLT3 in pancreatic cancer and to study the biological activity of combined inhibition of neovascularization and mitogenesis in this disease.. FLT3 expression was analyzed in 18 pancreatic cancer specimens by real-time quantitative polymerase chain reaction (RTQ-PCR) and immunohistochemistry. Sixteen pancreatic cancer cell lines were screened for ITD and D835 point mutations of the FLT3 gene. MTT assays and anchorage-independent growth assays were used to study cell growth. Flow cytometry was used for cell cycle analysis and apoptosis quantification. In vivo AsPC-1 and HPAF-II cells were used for orthotopic tumor modeling. Immunohistochemistry was used to quantify tumor angiogenesis.. FLT3 expression is down-regulated in pancreatic cancer. Activating FLT3 mutations (ITD, D835) were not detectable in any of the pancreatic cancer cell lines. Cell growth was significantly inhibited as cell-cycle progression was reduced and programmed cell death increased. In vivo PKC412 therapy resulted in a significant inhibition of orthotopic tumor growth with abrogation of tumor angiogenesis.. These data highlight that PKC412 may be a new compound in target therapy of inoperable pancreatic cancer patients and suggest a potential role for the combined use of broad spectrum kinase inhibitors in the management of these patients.

Topics: Adenocarcinoma; Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Flow Cytometry; fms-Like Tyrosine Kinase 3; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Male; Mice; Mice, Inbred BALB C; Microcirculation; Pancreatic Neoplasms; Point Mutation; Polymerase Chain Reaction; Protein Kinase C; Receptors, Vascular Endothelial Growth Factor; Sequence Analysis, DNA; Signal Transduction; Staurosporine; Tandem Repeat Sequences; Tumor Cells, Cultured

N-benzoyl-staurosporine (PKC412) is a selective inhibitor of protein kinase C, and it inhibits the growth of human cancer cells. In this study, we examined the antitumor effect of PKC412, given singly and in combination with paclitaxel, on tumor regression and chemotherapeutic side effects by assessing tumor burden and cytokine production responses in vivo. Twenty-six nude mice intraperitoneally inoculated with SKOV3 cells were treated differently in 4 treatment groups: PKC412 plus paclitaxel (n = 7), paclitaxel-only (n = 6), PKC412-only (n = 6), and controls (n = 7). At autopsy, we found that PKC412 itself slightly reduced the mass of tumor but did not fully inhibit tumor formation. The incidence of evident disease was decreased when PKC412 was combined with paclitaxel (43%). From the body weight of the tumor-bearing mice, we observed that PKC412 plus paclitaxel treated mice were less wasted than paclitaxel-only treated mice (18.1 g vs 22.4 g, p = 0.001). We measured intracellular TNFalpha, IFNgamma, IL-4, and IL-10 in stimulated mouse splenocytes using flow cytometry to determine if PKC412 inhibited cytokine production in T cells. TNFalpha, IFNgamma, and IL-10 production were all significantly inhibited in the paclitaxel-treated mice. The inhibitory effects on cytokine production by paclitaxel were compensated with PKC412 combination (p = 0.008, 0.035, 0.014, respectively). From this study, we deduce that PKC412 may have clinical applications in promoting tumor regression in ovarian cancer when combined with paclitaxel. Moreover, PKC412 is able to prevent weight loss and immunosuppression induced by paclitaxel because it rescues normal proliferating cells from cytotoxic effects.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Body Weight; Cell Line, Tumor; Cytokines; Drug Therapy, Combination; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Ovarian Neoplasms; Paclitaxel; Protein Kinase C; Spleen; Staurosporine; Xenograft Model Antitumor Assays

The staurosporine analogues CGP 41251, UCN-01 and Ro 31-8220 are specific inhibitors of protein kinase C (PKC). CGP 41251 and UCN-01 exert anti-neoplastic activity against human tumours grown in rodents, and CGP 41251 reverses multidrug resistance. The hypothesis was tested that these agents can induce drug resistance and alter cellular levels of target kinases. Human-derived A549 lung carcinoma cells were exposed for 6 months to CGP 41251, UCN-01 or Ro 31-8220 at gradually increasing concentrations. Cells acquired resistance against these agents, 4.3-fold against CGP 41251 (A549/CGP cells), 4.0-fold against UCN-01 (A549/UCN cells) and 14-fold against Ro 31-8220 (A549/Ro cells). Cells were neither collaterally cross-resistant towards the PKC inhibitors nor resistant against the growth-inhibitory properties of 12-O-tetradecanoylphorbol-13-acetate. However, cross-resistance was observed in A549/CGP cells against staurosporine (13-fold) and in A549/Ro cells against doxorubicin (26-fold). All 3 cell types expressed multidrug resistance-associated protein, and A549/Ro cells expressed P-glycoprotein, as adjudged by Western blot analysis. Phorbol ester-stimulated PKC activity in these cells was decreased by between 57% and 96% compared to wild-type A549 cells. Levels of the PKC isoenzymes alpha and theta in all 3 resistant cell types and of PKC-epsilon in A549/UCN cells were concomitantly reduced. Cells regained drug sensitivity after culture in the absence of drug for 6 (A549/Ro cells), 5 (A549/CGP cells) and 1 (A549/UCN cells) months. Our results suggest the following features of this type of anti-signalling drug: (i) they can induce drug resistance, (ii) they may be potentially useful in combination because of the lack of cross-resistance between them and (iii) they can down-regulate PKC, which may have pharmacological or toxicological consequences.

Topics: Adenocarcinoma; Alkaloids; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP-Binding Cassette Transporters; Cell Division; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Enzyme Inhibitors; Humans; Indoles; Lung Neoplasms; Multidrug Resistance-Associated Proteins; Protein Kinase C; Staurosporine; Tumor Cells, Cultured

The antitumor effect of CGP41251 (4'-N-benzoyl staurosporine), a selective protein kinase C (PKC) inhibitor, was examined on two kinds of human non-small cell lung cancer (NSCLC) cell lines (adenocarcinoma: A549 and squamous cell carcinoma: NCI-H520). CGP41251 at 0.5 or 1.0 microM inhibited the proliferation of these tumor cell lines significantly; However, at 0.1 microM, it did not show any significant inhibition. Cell cycle analysis indicated that CGP41251 at 0.5 or 1.0 microM arrested the cell cycle progression at the G2/M phase up to 24 hr, but 0.1 microM did not. It seems that the antiproliferative action of CGP41251 against human NSCLC is related to G2/M accumulation. In NCI-H520, CGP41251 caused DNA re-replication without mitosis. In a nude mice xenograft, CGP41251 at a dose of 200 mg/kg showed antitumor activity against these cell lines. Histopathologically, expansion of central necrosis was observed, although no destruction of tumor nests was seen by CGP41251 administration. In both tumor tissues, the PKC activity of the particulate fraction was significantly decreased by CGP41251 treatment. From these results, it is thought that the antitumor activity of CGP41251 against human NSCLS is accompanied by the decrease of PKC activity in the particulate fraction. Moreover, the G2/M arrest of the cell cycle induced by CGP41251 might be important for the growth inhibitory action of this compound.

Topics: Adenocarcinoma; Analysis of Variance; Animals; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Cycle; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Humans; Lung Neoplasms; Male; Mice; Mice, Nude; Neoplasm Transplantation; Protein Kinase C; Staurosporine; Tumor Cells, Cultured