Kinetics of Anti-SARS-CoV-2 Antibody Response Following Two Doses of the BNT162b2 mRNA Vaccine: A Japanese Single-Center Primary Care Clinic Report Involving Volunteers and Patients with Autoimmune Disease.

Despite the promising effectiveness of the coronavirus disease 2019 vaccination using an mRNA vaccine, the short efficacy duration and some poor responses to the vaccination remain major concerns. We aimed to clarify the monthly kinetics of the anti-SARS-CoV-2 spike receptor-binding domain antibody response after two doses of the BNT162b2 vaccine in a Japanese population. A chemiluminescent enzyme immunoassay (CLIA) and an enzyme-linked immunosorbent assay were used to measure the antibody levels in 81 Japanese adults (age, <65 years). The antibody levels increased 10-fold at 2−3 weeks following the second dose of BNT162b2 and declined thereafter to approximately 50%, 20%, and 10% of the peak levels at 2, 3, and 6 months, respectively. To compare the antibody titers among different groups, older adults (age, >65 years; n = 38) and patients with systemic lupus erythematosus (SLE, n = 14) were also investigated. A decline in the mean relative antibody titers was observed in older men compared with younger men and in patients with SLE compared with individuals aged <65 years. Although the antibody levels increased drastically following two BNT162b2 doses, they then declined rapidly. Furthermore, poor responders to the vaccination were observed. Repeated vaccinations are required to maintain high antibody levels.

Impact of high-dose statin on cardiovascular outcomes in real-world patients with ST-elevation acute myocardial infarction.

Little is known about the impact of a high-dose statin on cardiovascular outcomes after ST-elevation acute myocardial infarction (STEMI) in real-world Japanese patients. Between July 2011 and June 2017, 1110 consecutive STEMI patients underwent primary percutaneous coronary intervention at our hospital and were discharged. A high-dose statin was administered in 117 patients (10.5%) and non-high-dose statin was administered in 947 patients (85.3%). The low-density lipoprotein cholesterol level was significantly higher in the high-dose statin group at admission (129.8 ± 44.9 vs. 110.4 ± 32.7, p < 0.0001), but the levels were not significantly different at follow-up (86.7 ± 25.7 vs. 85.0 ± 25.0, p = 0.52). The cumulative 2-year incidence of a composite of cardiac death, myocardial infarction, ischemic stroke, and any unplanned coronary revascularization was significantly lower in the high-dose statin group (6.2% vs. 16.9%, log-rank p = 0.004). Propensity score matched analysis indicated similar results. Among the types of coronary revascularization, a high-dose statin was significantly correlated with a lower rate of de novo lesion revascularization (hazard ratio 0.31; 95% confidence interval 0.08-0.83; p = 0.02). The results of our analyses indicate that administration of a high-dose statin may result in better cardiovascular outcomes after STEMI mainly by reducing the rate of revascularization for de novo lesions regardless of the achieved low-density lipoprotein cholesterol level in real-world patients.

Simultaneous hyperthermia-chemotherapy effect by arterial injection of Fe(Salen) for femur tumor.

We previously identified a novel nanomagnetic particle, N,N'-bis(salicylidene)ethylenediamine iron [Fe(Salen)]. Fe(Salen) not only shows antitumor effects but also magnetic properties. We found that Fe(Salen) can be used for magnet-guided drug delivery and visualization of accumulated drug by magnetic resonance imaging (MRI) because of its magnetism. In addition, Fe(Salen) can generate heat by itself when exposed to an alternating current magnetic field (AMF), resulting in a hyperthermia effect. Herein, we partly elucidated the antitumor mechanism of Fe(Salen) and carried out an i.v. repeated dose toxicity study to decide the therapeutic amount. Furthermore, we evaluated the antitumor effect of selective intra-arterial injection or i.v. injection of Fe(Salen) by catheter and the hyperthermia effect of Fe(Salen) when exposed to AMF in vivo. We used a rabbit model grafted with VX2 cells (rabbit squamous cell carcinoma) on the right leg. Intra-arterial injection of Fe(Salen) showed a greater antitumor effect than did i.v. injection. The combination of Fe(Salen) intra-arterial injection and AMF exposure showed a greater antitumor effect than did either Fe(Salen) or methotrexate (MTX) without AMF exposure, suggesting that AMF exposure greatly enhanced the antitumor effect of Fe(Salen) by arterial injection by catheter. This is the first report that the effectiveness of Fe(Salen) was evaluated in the point of administration route; that is, selective intra-arterial injection by catheter. Taken together, these results indicate a new administration route; that is, selective arterial injection of Fe(Salen) by catheter, and the development of a new strategy of simultaneous hyperthermia-chemotherapy in the future.

Alternating magnetic field enhances cytotoxicity of Compound C.

We previously reported the efficacy of anti-cancer therapy with hyperthermia using an alternating magnetic field (AMF) and a magnetic compound. In the course of the study, unexpectedly, we found that an AMF enhances the cytotoxicity of Compound C, an activated protein kinase (AMPK) inhibitor, although this compound is not magnetic. Therefore, we examined the cellular mechanism of AMF-induced cytotoxicity of Compound C in cultured human glioblastoma (GB) cells. An AMF (280 kHz, 250 Arms) for 30 minutes significantly enhanced the cytotoxicity of Compound C and promoted apoptosis towards several human GB cell lines in vitro. The AMF also increased Compound C-induced cell-cycle arrest of GB cells at the G2 phase and, thus, inhibited cell proliferation. The AMF increased Compound C-induced reactive oxygen species production. Furthermore, the AMF decreased ERK phosphorylation in the presence of Compound C and suppressed the protective autophagy induced by this compound. The application of an AMF in cancer chemotherapy may be a simple and promising method, which might reduce the doses of drugs used in future cancer treatment and, therefore, the associated side effects.

Treatment of oral cancer using magnetized paclitaxel.

N,N'-Bis(salicylidene)ethylenediamine iron (Fe(Salen)) is an anti-cancer agent with intrinsic magnetic property. Here, we covalently linked Fe(Salen) to paclitaxel (PTX), a widely used anti-cancer drug, to obtain a magnetized paclitaxel conjugate (M-PTX), which exhibited magnetic characteristics for magnet-guided drug delivery and MRI visualization. M-PTX increased apoptosis and G2/M arrest of cultured human oral cancer cell lines in the same manner as PTX. Furthermore, marked contrast intensity was obtained in magnetic resonance imaging (MRI) of M-PTX. In a mouse oral cancer model, a permanent magnet placed on the body surface adjacent to the tumor resulted in distinct accumulation of M-PTX, and the anti-cancer effect was greater than that of M-PTX without the magnet. We believe that this strategy may improve future cancer chemotherapy by providing conventional anti-cancer drugs with novel functionalities such as magnet-guided drug delivery or MRI-based visualization/quantitation of drug distribution.

Relationship between n-3 Polyunsaturated Fatty Acids and Extent of Vessel Disease in Patients with ST Elevation Myocardial Infarction.

A relationship between serum polyunsaturated fatty acids (PUFAs) and cardiovascular disease has been reported; however, the existence of a relationship between serum PUFAs and extent of vessel disease (VD) in patients with ST elevation myocardial infarction (STEMI) remains unclear.Between July 2011 and June 2015, 866 consecutive STEMI patients underwent emergent percutaneous coronary intervention, 507 of whom were enrolled and classified into three groups according to the initial angiograms: 1VD, 294 patients; 2VD, 110 patients; and 3VD/left main trunk disease (LMTD), 103 patients. Serum levels of PUFAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid, and other laboratory data during hospitalization were evaluated.The serum EPA level in the 3VD/LMTD group was significantly lower than that in the 1VD group (55.5 ± 22.1 versus 66.2 ± 28.7, P = 0.002) and was slightly lower than that in the 2VD group (55.5 ± 22.1 versus 65.2 ± 28.9, P = 0.0167). Multivariate adjustment analysis revealed that age ≥ 70 years (odds ratio, 1.72; 95% confidence interval, 1.03-2.89; P = 0.038) and a low serum EPA level (odds ratio, 0.98; 95% confidence interval, 0.99-1.00; P = 0.023) were independent risk factors for 3VD/LMTD, while a low serum DHA level was not.A low serum EPA level may be more strongly related than a low serum DHA level to the extent of VD in STEMI patients. Age ≥ 70 years and a low serum EPA level may be independent risk factors for 3VD/LMTD.

The iron chelating agent, deferoxamine detoxifies Fe(Salen)-induced cytotoxicity.

Iron-salen, i.e., µ-oxo-N,N'-bis(salicylidene)ethylenediamine iron (Fe(Salen)) was a recently identified as a new anti-cancer compound with intrinsic magnetic properties. Chelation therapy has been widely used in management of metallic poisoning, because an administration of agents that bind metals can prevent potential lethal effects of particular metal. In this study, we confirmed the therapeutic effect of deferoxamine mesylate (DFO) chelation against Fe(Salen) as part of the chelator antidote efficacy. DFO administration resulted in reduced cytotoxicity and ROS generation by Fe(Salen) in cancer cells. DFO (25 mg/kg) reduced the onset of Fe(Salen) (25 mg/kg)-induced acute liver and renal dysfunction. DFO (300 mg/kg) improves survival rate after systematic injection of a fatal dose of Fe(Salen) (200 mg/kg) in mice. DFO enables the use of higher Fe(Salen) doses to treat progressive states of cancer, and it also appears to decrease the acute side effects of Fe(Salen). This makes DFO a potential antidote candidate for Fe(Salen)-based cancer treatments, and this novel strategy could be widely used in minimally-invasive clinical settings.

Anticancer luminescent gold quantum clusters for in situ cancer-selective marking-imaging-targeting.

Ultrafine Au quantum clusters (QCs) were synthesized by etching host Au nanoparticles in the presence of ethylenediamine (en) and exhibited both strong photoluminescence (PL) and specific anticancer activity. The cutting-edge feature of this QC compound comprises subnanometer-size rhombohedral Au8, which consists of 8 units of the anticancer motif, namely, an Au+(en) complex (Au(en)QCs), which contributes to photo- and physicochemical stability as well as subcellular theranostic activity in intracellular PL imaging and in situ targeting. Moreover, the Au(en)QCs can be surface-encapsulated by transferrins (Tf) to create TfAu(en)QCs as a multipurpose drug carrier owing to numerous merits, which include cancer-selective biolabeling, high loading/release efficiency, high activity against drug-resistant tumor cells, low toxicity to normal cells, and physiological stability against biothiols, e.g., glutathiones. These versatile features, which are due to intrinsic optical and anticancer properties, provide potential as a single-drug delivery PL probe for preclinical applications, which has yet to be achieved using conventional nanoclusters.

Hyperthermia and chemotherapy using Fe(Salen) nanoparticles might impact glioblastoma treatment.

We previously reported that µ-oxo N,N'-bis(salicylidene)ethylenediamine iron [Fe(Salen)], a magnetic organic compound, has direct anti-tumor activity, and generates heat in an alternating magnetic field (AMF). We showed that Fe(Salen) nanoparticles are useful for combined hyperthermia-chemotherapy of tongue cancer. Here, we have examined the effect of Fe(Salen) on human glioblastoma (GB). Fe(Salen) showed in vitro anti-tumor activity towards several human GB cell lines. It inhibited cell proliferation, and its apoptosis-inducing activity was greater than that of clinically used drugs. Fe(Salen) also showed in vivo anti-tumor activity in the mouse brain. We evaluated the drug distribution and systemic side effects of intracerebrally injected Fe(Salen) nanoparticles in rats. Further, to examine whether hyperthermia, which was induced by exposing Fe(Salen) nanoparticles to AMF, enhanced the intrinsic anti-tumor effect of Fe(Salen), we used a mouse model grafted with U251 cells on the left leg. Fe(Salen), BCNU, or normal saline was injected into the tumor in the presence or absence of AMF exposure. The combination of Fe(Salen) injection and AMF exposure showed a greater anti-tumor effect than did either Fe(Salen) or BCNU alone. Our results indicate that hyperthermia and chemotherapy with single-drug nanoparticles could be done for GB treatment.

Simultaneous hyperthermia-chemotherapy with controlled drug delivery using single-drug nanoparticles.

We previously investigated the utility of µ-oxo N,N'- bis(salicylidene)ethylenediamine iron (Fe(Salen)) nanoparticles as a new anti-cancer agent for magnet-guided delivery with anti-cancer activity. Fe(Salen) nanoparticles should rapidly heat up in an alternating magnetic field (AMF), and we hypothesized that these single-drug nanoparticles would be effective for combined hyperthermia-chemotherapy. Conventional hyperthermic particles are usually made of iron oxide, and thus cannot exhibit anti-cancer activity in the absence of an AMF. We found that Fe(Salen) nanoparticles induced apoptosis in cultured cancer cells, and that AMF exposure enhanced the apoptotic effect. Therefore, we evaluated the combined three-fold strategy, i.e., chemotherapy with Fe(Salen) nanoparticles, magnetically guided delivery of the nanoparticles to the tumor, and AMF-induced heating of the nanoparticles to induce local hyperthermia, in a rabbit model of tongue cancer. Intravenous administration of Fe(Salen) nanoparticles per se inhibited tumor growth before the other two modalities were applied. This inhibition was enhanced when a magnet was used to accumulate Fe(Salen) nanoparticles at the tongue. When an AMF was further applied (magnet-guided chemotherapy plus hyperthermia), the tumor masses were dramatically reduced. These results indicate that our strategy of combined hyperthermia-chemotherapy using Fe(Salen) nanoparticles specifically delivered with magnetic guidance represents a powerful new approach for cancer treatment.

A magnetic anti-cancer compound for magnet-guided delivery and magnetic resonance imaging.

Research on controlled drug delivery for cancer chemotherapy has focused mainly on ways to deliver existing anti-cancer drug compounds to specified targets, e.g., by conjugating them with magnetic particles or encapsulating them in micelles. Here, we show that an iron-salen, i.e., µ-oxo N,N'- bis(salicylidene)ethylenediamine iron (Fe(Salen)), but not other metal salen derivatives, intrinsically exhibits both magnetic character and anti-cancer activity. X-Ray crystallographic analysis and first principles calculations based on the measured structure support this. It promoted apoptosis of various cancer cell lines, likely, via production of reactive oxygen species. In mouse leg tumor and tail melanoma models, Fe(Salen) delivery with magnet caused a robust decrease in tumor size, and the accumulation of Fe(Salen) was visualized by magnetic resonance imaging. Fe(Salen) is an anti-cancer compound with magnetic property, which is suitable for drug delivery and imaging. We believe such magnetic anti-cancer drugs have the potential to greatly advance cancer chemotherapy for new theranostics and drug-delivery strategies.

Hyperthermia generated with ferucarbotran (Resovist®) in an alternating magnetic field enhances cisplatin-induced apoptosis of cultured human oral cancer cells.

Hyperthermia is a promising anti-cancer treatment in which the tissue temperature is increased to 42-45 °C, and which is often used in combination with chemotherapy or radiation therapy. Our aim in the present work was to examine the feasibility of combination therapy for oral cancer with cisplatin and hyperthermia generated with ferucarbotran (Resovist(®); superparamagnetic iron oxide) in an alternating magnetic field (AMF). First, we established that administration of ferucarbotran at the approved dosage for magnetic resonance imaging provides an iron concentration sufficient to increase the temperature to 42.5 °C upon exposure to AMF. Then, we examined the effect of cisplatin combined with ferucarbotran/AMF-induced hyperthermia on cultured human oral cancer cells (HSC-3 and OSC-19). Cisplatin alone induced apoptosis of cancer cells in a dose-dependent manner, as is well known. However, the combination of cisplatin with ferucarbotran/AMF was significantly more effective than cisplatin alone. This result suggests that it might be possible to reduce the clinically effective dosage of cisplatin by administering it in combination with ferucarbotran/AMF-induced hyperthermia, thereby potentially reducing the incidence of serious cisplatin-related side effects. Further work seems justified to evaluate simultaneous thermo-chemotherapy as a new approach to anticancer therapy.

Association between tissue characteristics evaluated with optical coherence tomography and mid-term results after paclitaxel-coated balloon dilatation for in-stent restenosis lesions: a comparison with plain old balloon angioplasty.

AIMS: Morphological assessment of neointimal tissue using optical coherence tomography (OCT) is important for clarifying the pathophysiology of in-stent restenosis (ISR) lesions. The aim of this study was to determine the impact of OCT findings on recurrence of ISR after paclitaxel-coated balloon (PCB) dilatation compared with plain old balloon angioplasty (POBA). METHODS AND RESULTS: Between July 2008 and May 2012, we performed percutaneous coronary intervention for 214 ISR lesions using POBA + PCB (146 lesions, PCB group) or POBA only (68 lesions, POBA group). Morphological assessment of neointimal tissue using OCT, including assessment of restenotic tissue structure and restenotic tissue backscatter, was performed. We examined the association between lesion morphologies and mid-term (6-8 months) results including ISR and target lesion revascularization (TLR) rates. Both ISR and TLR rates of lesions with a homogeneous structure were significantly lower in the PCB group than those in the POBA group (ISR: 20.0 vs. 55.6%, P = 0.002, TLR: 12.7 vs. 37.0%, P = 0.019), but there was no difference between the two groups in ISR and TLR rates of lesions with a heterogeneous or layered structure. Both ISR and TLR rates of lesions with high backscatter were significantly lower in the PCB group than those in the POBA group (ISR: 19.8 vs. 52.5%, P < 0.001, TLR: 13.6 vs. 42.5%, P = 0.001), but there was no difference between the two groups in ISR and TLR rates of lesions with low backscatter. CONCLUSION: Morphological assessment of ISR tissue using OCT might be useful for identifying ISR lesions favourable for PCB dilatation.

Seven-year clinical outcomes of unprotected left main coronary artery stenting with drug-eluting stent and bare-metal stent.

BACKGROUND: The superiority of drug-eluting stents (DES) over bare-metal stents (BMS) 7 years after unprotected left main coronary artery (LMCA) stenting has not been investigated. METHODS AND RESULTS: From 2003 to 2005, 182 patients underwent stent implantation for unprotected LMCA disease (DES, 96 patients; BMS, 86 patients; acute coronary syndrome cases excluded), and the 7-year clinical outcomes between the DES and BMS groups were compared. The incidence of cardiac death or non-fatal myocardial infarction was similar between the DES and BMS groups (11.0% vs. 13.5%, P=0.78). The incidence of target lesion revascularization (TLR) at 7 years was significantly lower in the DES group than in the BMS group (26.4% vs. 40.5%, P=0.009); the incidence from 1 to 4 years and that beyond 4 years were similar between the DES and BMS groups (8.9% vs. 7.9%, P=0.97; 10.0% vs. 8.7%, P=0.74, respectively). Among patients with bifurcation lesions, whereas the incidence of 7-year TLR was significantly lower in the DES group than the BMS group in patients undergoing single-stent procedures (15.9% vs. 48.6%, P=0.002), it was similar between the 2 groups in patients undergoing 2-stent procedures (38.5% vs. 39.3%, P=0.49). CONCLUSIONS: With the exception of the 2-stent procedure, the 7-year outcomes after DES implantation for LMCA disease were superior to those after BMS implantation because of the lower TLR rate, when considering TLR during the late phase.

Difference in clinical and angiographic characteristics of very late stent thrombosis between drug-eluting and bare-metal stent implantations.

BACKGROUND: Limited data are available with which to compare the clinical characteristics of patients with very late stent thrombosis (VLST) after drug-eluting stent (DES) or bare-metal stent (BMS) implantation. The purpose of this study was to investigate the differences in the characteristics of VLST after DES and BMS implantation by reviewing the clinical and angiographic data. METHODS AND RESULTS: A total of 28 patients (30 lesions) with VLST after DES implantation and 33 patients (33 lesions) with VLST after BMS implantation were identified. The occurrence of VLST after BMS implantation (2,647±996 days) was much later than that after DES implantation (1,194±558 days, P<0.001). The number of VLST after DES implantation increased gradually each year; however VLST after BMS implantation started to occur >50 months later, and its number increased subsequently. The prevalence of VLST related to surgical procedures involving discontinuation of antiplatelet therapy in VLST patients was higher after DES implantation (14.3%) than after BMS implantation (0%, P=0.039). Angiographic stent fracture was seen in 36.7% of VLST lesions after DES implantation at different times (464-2,102 days after procedure), while none was seen in VLST lesions after BMS implantation (P<0.001). CONCLUSIONS: The timing of VLST was different after DES and BMS implantation. Stent fracture was a specific finding of VLST after DES implantation.

Optical coherence tomography findings in lesions after sirolimus-eluting stent implantation with peri-stent contrast staining.

BACKGROUND: We have sometimes noted abnormal angiographic coronary dilatation, <50% of the reference vessel, at the site of sirolimus-eluting stent implantation, suggesting contrast staining outside the stent struts and named this finding peri-stent contrast staining (PSS). Little was known about optical coherence tomography findings of lesions with PSS. METHODS AND RESULTS: Between May 2008 and March 2010, we performed optical coherence tomography for 90 in-stent restenosis lesions after sirolimus-eluting stent implantation. We found PSS in 20 of the 90 lesions by coronary angiography. The differences in optical coherence tomography findings, including incomplete stent apposition, multiple interstrut hollows (MIH), strut coverage, and thrombus, were compared between lesions with PSS and those without PSS. PSS is defined as contrast staining outside the stent contour extending to >20% of the stent diameter measured by quantitative coronary angiography. MIH is defined as multiple hollows (the maximum depth >0.5 mm) existing between and outside well-apposed stent struts. Both incomplete stent apposition (60.0% versus 10%; P<0.001) and MIH (85.0% versus 25.7%; P<0.001) were frequently observed in lesions with PSS than in lesions without PSS. Among the 20 lesions with PSS, there was only 1 lesion in which we found neither MIH nor incomplete stent apposition, but only minor dissection. Uncovered struts (11.6% versus 3.9%; P=0.001), malapposed struts (2.0% versus 0.0%; P<0.001), and red thrombus (35% versus 10%; P=0.012) were frequently observed in lesions with PSS than in lesions without PSS. CONCLUSIONS: PSS might be closely associated with 2 different optical coherence tomography findings, MIH and incomplete stent apposition, in lesions after sirolimus-eluting stent implantation.

Effect of ascorbic acid on reactive oxygen species production in chemotherapy and hyperthermia in prostate cancer cells.

Cellular reactive oxygen species (ROS) production is increased by both temperature and anticancer drugs. Antioxidants are known to suppress ROS production while cancer patients may take them as dietary supplement during chemotherapy and hyperthermic therapy. We examined changes in ROS production in prostate cancer cells in the presence of various anticancer drugs and antioxidants at different temperatures. ROS production was increased with temperature in cancer cells, but not in normal cells; this increase was potently inhibited by ascorbic acid. ROS production was also increased in the presence of some anticancer drugs, such as vinblastine, but not by others. Dietary antioxidant supplements, such as ß-carotene, showed variable effects. Ascorbic acid potently inhibited ROS production, even in the presence of anticancer drugs, while ß-carotene showed no inhibition. Accordingly, our results suggest that cancer patients should carefully choose antioxidants during their cancer chemotherapy and/or hyperthermic therapy.

Effectiveness of paclitaxel-eluting balloon catheter in patients with sirolimus-eluting stent restenosis.

OBJECTIVES: The aim of this study was to investigate the efficacy of a paclitaxel-eluting balloon (PEB) for the treatment of sirolimus-eluting stent (SES) restenosis. BACKGROUND: Because drug-eluting stents (DES) are being used in increasingly complicated settings, DES restenosis is no longer an uncommon phenomenon, and its optimal treatment is unknown. METHODS: This study was a prospective single-blind randomized trial conducted in 50 patients with SES restenosis. Patients were randomly assigned to a PEB group (n = 25) or a conventional balloon angioplasty (BA) group (n = 25). The primary end point was late lumen loss at 6-month follow-up. Secondary end points included the rate of binary restenosis (in-segment analysis) and major adverse cardiac events (MACE) at 6-month follow-up. RESULTS: At 6-month angiographic follow-up (follow-up rate: 94%), in-segment late lumen loss was lower in the PEB group than in the BA group (0.18 ± 0.45 mm vs. 0.72 ± 0.55 mm; p = 0.001). The incidence of recurrent restenosis (8.7% vs. 62.5%; p = 0.0001) and target lesion revascularization (4.3% vs. 41.7%; p = 0.003) was also lower in the PEB group than in the BA group. The cumulative MACE-free survival was significantly better in the PEB group than in the BA group (96% vs. 60%; p = 0.005). CONCLUSIONS: In patients with SES restenosis, PEB provided much better clinical, angiographic outcomes than conventional BA.

cAMP-mediated regulation of CYP enzymes and its application in chemotherapy.

Certain anti-cancer prodrugs are subject to cytochrome P450 (CYP)-mediated metabolism and become more active. Because CYP activity may be regulated by phosphorylation via adenylyl cyclase/protein kinase A, selective adenylyl cyclase subtype activators may be utilized in future chemotherapy to regulate CYP activity as a switch in a tumor tissue-specific manner.