Small is beautiful: A ring-contracted sister of porphyrin, norcorrole, has been synthesized efficiently as a stable molecule by a nickel-templated strategy. The norcorrole complex is stable but exhibits a distinct antiaromatic character according to the Hückel rule. Oxidation of the norcorrole complex provides an aromatic oxacorrole complex.

Rationale: Phosphate (Pi) is an essential nutrient to living organisms. Recent surveys indicate that the intake of Pi has increased steadily. Our previous studies have indicated that elevated Pi activates the Akt signaling pathway. An increased knowledge of the response of lung cancer tissue to high dietary Pi may provide an important link between diet and lung tumorigenesis. Objectives: The current study was performed to elucidate the potential effects of high dietary Pi on lung cancer development. Methods: Experiments were performed on 5-week-old male K-ras LA1 lung cancer model mice and 6-week-old male urethane-induced lung cancer model mice. Mice were fed a diet containing 0.5% Pi (normal Pi) and 1.0% Pi (high Pi) for 4 weeks. At the end of the experiment, all mice were killed. Lung cancer development was evaluated by diverse methods. Measurement and Main Results: A diet high in Pi increased lung tumor progression and growth compared with normal diet. High dietary Pi increased the sodium-dependent inorganic phosphate transporter2b protein levels in the lungs. High dietary consumption of Pi stimulated pulmonary Akt activity while suppressing the protein levels of tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 as well as Akt binding partner carboxyl-terminal modulator protein, resulting in facilitated cap-dependent protein translation. In addition, high dietary Pi significantly stimulated cell proliferation in the lungs of K-ras LA1 mice. Conclusions: Our results showed that high dietary Pi promoted tumorigenesis and altered Akt signaling, thus suggesting that careful regulation of dietary Pi may be critical for lung cancer prevention as well as treatment.

Aromaticity is a key concept in organic chemistry. Even though this concept has already been theoretically extrapolated to three dimensions, it usually still remains restricted to planar molecules in organic chemistry textbooks. Stacking of antiaromatic π-systems has been proposed to induce three-dimensional aromaticity as a result of strong frontier orbital interactions. However, experimental evidence to support this prediction still remains elusive so far. Here we report that close stacking of antiaromatic porphyrins diminishes their inherent antiaromaticity in the solid state as well as in solution. The antiaromatic stacking furthermore allows a delocalization of the π-electrons, which enhances the two-photon absorption cross-section values of the antiaromatic porphyrins. This feature enables the dynamic switching of the non-linear optical properties by controlling the arrangement of antiaromatic π-systems on the basis of intermolecular orbital interactions.

The tumor-tropic properties of neural stem cells (NSCs) led to the development of a novel strategy for delivering therapeutic genes to tumors in the brain. To apply this strategy to the treatment of brain metastases, we made a human NSC line expressing cytosine deaminase (F3.CD), which converts 5-fluorocytosine (5-FC) into 5-fluorouracil, an anticancer agent. In vitro, the F3.CD cells significantly inhibited the growth of tumor cell lines in the presence of the prodrug 5-FC. In vivo, MDA-MB-435 human breast cancer cells were implanted into the brain of immune-deficient mouse stereotactically, and F3.CD cells were injected into the contralateral hemisphere followed by systemic 5-FC administration. The F3.CD cells migrated selectively into the brain metastases located in the opposite hemisphere and resulted in significantly reduced volumes. The F3.CD and 5-FC treatment also decreased both tumor volume and number of tumor mass significantly, when immune-deficient mouse had MDA-MB-435 cells injected into the internal carotid artery and F3.CD cells were transplanted into the contralateral brain hemisphere stereotactically. Taken together, brain transplantation of human NSCs, encoding the suicide enzyme CD, combined with systemic administration of the prodrug 5-FC, is an effective treatment regimen for brain metastases of tumors.

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