α-PD-1 therapy elevates Treg/Th balance and increases tumor cell pSmad3 that are both targeted by α-TGFß antibody to promote durable rejection and immunity in squamous cell carcinomas.

BACKGROUND: Checkpoint blockade immunotherapy has improved metastatic cancer patient survival, but response rates remain low. There is an unmet need to identify mechanisms and tools to circumvent resistance. In human patients, responses to checkpoint blockade therapy correlate with tumor mutation load, and intrinsic resistance associates with pre-treatment signatures of epithelial mesenchymal transition (EMT), immunosuppression, macrophage chemotaxis and TGFß signaling. METHODS: To facilitate studies on mechanisms of squamous cell carcinoma (SCC) evasion of checkpoint blockade immunotherapy, we sought to develop a novel panel of murine syngeneic SCC lines reflecting the heterogeneity of human cancer and its responses to immunotherapy. We characterized six Kras-driven cutaneous SCC lines with a range of mutation loads. Following implantation into syngeneic FVB mice, we examined multiple tumor responses to α-PD-1, α-TGFß or combinatorial therapy, including tumor growth rate and regression, tumor immune cell composition, acquired tumor immunity, and the role of cytotoxic T cells and Tregs in immunotherapy responses. RESULTS: We show that α-PD-1 therapy is ineffective in establishing complete regression (CR) of tumors in all six SCC lines, but causes partial tumor growth inhibition of two lines with the highest mutations loads, CCK168 and CCK169. α-TGFß monotherapy results in 20% CR and 10% CR of established CCK168 and CCK169 tumors respectively, together with acquisition of long-term anti-tumor immunity. α-PD-1 synergizes with α-TGFß, increasing CR rates to 60% (CCK168) and 20% (CCK169). α-PD-1 therapy enhances CD4 + Treg/CD4 + Th ratios and increases tumor cell pSmad3 expression in CCK168 SCCs, whereas α-TGFß antibody administration attenuates these effects. We show that α-TGFß acts in part through suppressing immunosuppressive Tregs induced by α-PD-1, that limit the anti-tumor activity of α-PD-1 monotherapy. Additionally, in vitro and in vivo, α-TGFß acts directly on the tumor cell to attenuate EMT, to activate a program of gene expression that stimulates immuno-surveillance, including up regulation of genes encoding the tumor cell antigen presentation machinery. CONCLUSIONS: We show that α-PD-1 not only initiates a tumor rejection program, but can induce a competing TGFß-driven immuno-suppressive program. We identify new opportunities for α-PD-1/α-TGFß combinatorial treatment of SCCs especially those with a high mutation load, high CD4+ T cell content and pSmad3 signaling. Our data form the basis for clinical trial of α-TGFß/α-PD-1 combination therapy (NCT02947165).

A mass spectrometric and quantum chemical study of the vaporisation of lead monoxide in a flow of gaseous arsenic and antimony trioxides.

Mass spectrometric studies of the vapours over solid lead oxide in a flow of gaseous arsenic and antimony trioxides were conducted. The following ions of the ternary oxides were detected: Pb3As2O6(+), Pb3AsO4(+), PbAs2O4(+), PbAsO2(+), PbSb2O4(+), and PbSbO2(+). The origin of these species produced by the ionisation and/or fragmentation of ternary gaseous oxides is discussed. The PbAs2O4 species was undoubtedly identified by the determination of the appearance energy. Presumably, the Pb3As2O6 and PbSb2O4 species also existed in the gas phase. Thermodynamic data for the ternary oxides were obtained experimentally by means of a mass spectrometric Knudsen-cell method and were confirmed by quantum chemical calculations.

PS2Br and AsS2X (X = Br, I): similar molecules with completely different shapes--a combined experimental and theoretical study.

By the reaction of solid As(4)S(4) with gaseous Br(2) at a temperature of 410 K gaseous AsSBr and AsS(2)Br are formed; the reaction with gaseous I(2) at 468 K leads to the formation of AsSI, AsS(2)I, As(2)S(2)I(2) and As(2)S(3)I(2). Thermodynamic data on these novel species are obtained by mass spectrometry. The experimental findings are extended and confirmed by ab initio quantum chemical calculations. Undoubtedly the molecules AsSX (X = Br, I) and As(2)S(2)I(2) contain As-atoms in the formal oxidation state III. Unexpectedly, in AsS(2)X arsenic is not of formal oxidation state +V but +III: due to the absence of As-S π-bonding, the molecular structure of AsS(2)X is arranged as a dithia-arsirane with an AsS(2) three-membered ring. For comparison with AsS(2)X, PS(2)Br is investigated for the first time. This high temperature species is planar with symmetry C(2v) and phosphorus of the formal oxidation state +V in which the two P=S π-bonds are realized due to their strength over one S-S σ-bond. As(2)S(3)I(2) contains a five-membered As(2)S(3)-ring with one S-S-bond. The ionization energies are determined and compared with those obtained from calculations; they serve as a further indication for the structures realized in these molecules.

Formation and stability of molybdenum-tellurium oxides MoTeO5, Mo2TeO8, Mo3TeO11 and MoTe2O7 in the gas phase. Quantum chemical and mass spectrometry determination of standard enthalpy of formation.

The formation of mixed molybdenum-tellurium oxides MoTeO5, Mo2TeO8, Mo3TeO11, MoTe2O7 in the gas phase has been studied by mass spectrometry (MS) experiments at temperatures of about 938 K and studied theoretically by quantum chemical (QC) methods. Structural and thermodynamic data for the molecules was calculated. The mixed oxides MoTeO5, Mo2TeO8, Mo3TeO11 and MoTe2O7 in the gas phase have been reported for the first time. Experimental thermodynamic data have been determined by means of MS and confirmed theoretically by DFT and ab initio (MP2) calculations. Adiabatic ionisation potentials (IPs) were obtained experimentally and compared with theoretical vertical ionisation potentials. The following values are given: Δ(f)H(298)(0) (MoTeO5) = −730.2 kJ mol(−1) (MS), Δ(f)H(298)(0) (MoTeO5) = −735.4 kJ mol(−1) (DFT), −717.3 kJ mol(−1) (MP2), S(298)(0) (MoTeO5) = 389.5 J mol(−1) K(−1) (DFT), c(p)(0)(T)(MoTeO5) = 141.71 + 13.54 × 10(−3)T − 2.53 × 10(6)T(−2) J mol(−1) K(−1) (298 < T < 940 K) (DFT), Δ(f)H(298)(0) (Mo2TeO8) = −1436.3 kJ mol(−1) (MS), Δ(f)H(298)(0) (Mo2TeO8) = −1436.1 kJ mol(−1) (DFT), −1455.9 kJ mol(−1) (MP2), S(298)(0) (Mo2TeO8) = 517.1 J mol(−1) K(−1) (DFT), c(p)(0)(T)(Mo2TeO8) = 228.64 + 24.15 × 10(−3)T − 4.09 × 10(6)T(−2) J mol(−1) K(−1) (298 < T < 940 K) (DFT), Δ(f)H(298)(0) (Mo3TeO11) = −2132.7 kJ mol(−1) (MS), Δ(f)H(298)(0) (Mo3TeO11) = −2110.7 kJ mol(−1) (DFT), −2163.2 kJ mol(−1) (MP2), S(298)(0) (Mo3TeO11) = 629.3 J mol(−1) K(−1) (DFT), c(p)(0)(T)(Mo3TeO11) = 316.40 + 34.10 × 10(−3)T − 5.74 × 10(6)T(−2) J mol(−1) K(−1) (298 < T < 940 K) (DFT), Δ(f)H(298)(0) (MoTe2O7) = −999.7 kJ mol(−1) (MS), Δ(f)H(298)(0) (MoTe2O7) = −1002.7 kJ mol(−1) (DFT), −1000.9 kJ mol(−1) (MP2), S(298)(0) (MoTe2O7) = 504.8 J mol(−1) K(−1) (DFT), c(p)(0)(T)(MoTe2O7) = 211.19 + 18.02 × 10(−3)T − 3.53 × 10(6)T(−2) J mol(−1) K(−1) (298 < T < 940 K) (DFT), IP(MoTeO5) = 10.68 eV (DFT), IP(Mo2TeO8) = 10.4 ± 0.5 eV (MS), IP(Mo2TeO8) = 10.41 eV (DFT), IP(Mo3TeO11) = 10.7 ± 0.5 eV (MS), IP(Mo3TeO11) = 10.18 eV (DFT), IP(MoTe2O7) = 9.91 eV (DFT).

The formation and stability of molybdenum-antimony and tungsten-antimony ternary oxides Sb2MO6, Sb2M2O9, Sb2Mo3O12 and Sb4MO9 in the gas phase (M = Mo, W). Quantum chemical and mass spectrometric studies.

The ternary oxides Sb(2)MO(6), Sb(2)M(2)O(9), Sb(4)MO(9) (M = Mo, W) and Sb(2)Mo(3)O(12) were detected in the gas phase by means of mass spectrometry (MS). These gaseous oxides are reported for the first time. Thermodynamic data was obtained experimentally and confirmed by quantum chemical (QC) calculations. In addition, structural data on these molecules was obtained. The ionisation potentials (IP) were also determined both experimentally and theoretically.

AsS2Cl-an Arsenic(V) compound? Formation, stability and structure of gaseous AsSCl and AsS2Cl--a combined experimental and theoretical study.

By reaction of solid As(4)S(4) with gaseous Cl(2) at a temperature of 410 K gaseous AsSCl and AsS(2)Cl are formed. Unexpectedly in AsS(2)Cl the arsenic is not of formal oxidation state +V but +III: the molecular structure of AsS(2)Cl is arranged as a 1-chloro-dithia-arsirane and comprises an hitherto unknown AsS(2) three-membered ring. Thermodynamic data on AsSCl and AsS(2)Cl are obtained by mass spectrometry (MS). The experimental data are extended and confirmed by ab initio quantum chemical calculations (QC). The following values are given: Δ(f)H(0)(298)(AsSCl) = -5.2 kJ mol(-1) (MS), Δ(f)H(0)(298)(AsSCl) = 1.7 kJ mol(-1) (QC), S(0)(298)(AsSCl) = 296.9 J K(-1) mol(-1) (QC) and c(p)(0)(T)(AsSCl) = 55.77 + 3.97 × 10(-3)T- 4.38 × 10(5)T(-2)- 1.83 × 10(-6)T(2) and Δ(f)H(0)(298)(AsS(2)Cl) = -39.0 kJ mol(-1) (MS), Δ(f)H(0)(298)(AsS(2)Cl) = -20.2 kJ mol(-1) (QC), S(0)(298)(AsS(2)Cl) = 321.3 J K(-1) mol(-1) (QC) and c(p)(0)(T)(AsS(2)Cl) = 80.05 + 5.09 × 10(-3)T- 7.61 × 10(5)T(-2)- 2.35 × 10(-6)T(2) (298.15 K < T < 1000 K) (QC). The ionization energies are determined (IP(AsSCl) = 10.5, IP(AsS(2)Cl) = 10.2 eV). The IR spectrum of AsSCl is detected by means of matrix isolation spectroscopy. The estimated force constant f(As=S) = 4.47 mdyn·Å(-1) gives rise to an As=S double bond.