Valproic acid (VPA) is an established drug in the long-term therapy of seizure disorders. Recently, VPA has been associated with anticancer activity, an effect thought to be mediated through the inhibition of cellular histone deacetylase 1. We investigated the effect of various doses of VPA (0, 1.2, and 5.0 mmol/L) administered either acutely or chronically on histone acetylation, p21 gene expression, androgen receptor expression, prostate-specific antigen (PSA) expression, and cell survival and proliferation in prostate cancer cell lines. We also studied the effect of chronic VPA on tumor xenograft growth in vivo. Our results show that acute treatment (3 days) VPA can increase net histone H3 acetylation and up-regulate p21, AR, and cytosolic PSA expression. Interestingly, the effects on AR and PSA are reversed with chronic teatment. In addition, acute VPA reduces cell survival but has no effect on the subsequent proliferation of surviving cells following drug withdrawal. However, when VPA is chronically administered (10-14 days) to prostate cancer cells, even lower doses of VPA result in marked decreases in the net proliferation rate, correlating with increased caspase-2 and caspase-3 activation. These effects are evident in both androgen receptor-positive (LNCaP and C4-2) and androgen receptor-negative (DU145 and PC3) prostate cancer cells. Moreover, chronic VPA treatment results in statistically significant reduction of tumor xenograft growth in vivo. We conclude that acute treatment has nominal effects on prostate cancer cell survival and proliferation, but chronic VPA results in profound decreases in proliferation, independently of androgen regulation. (Cancer Res 2006; 66(14): 7237-44)

Purpose: The prostate-specific membrane antigen (PSMA) is a surface glycoprotein overexpressed on malignant prostate cells, as well as in the neovasculature of many tumors. Recent efforts to target PSMA for imaging prostate cancer rely on suitably functionalized low-molecular-weight agents. YC-27 is a low-molecular-weight, urea-based agent that enables near-infrared (NIR) imaging of PSMA in vivo. Experimental Design: We have developed and validated a laparoscopic imaging system (including an optimized light source, LumiNIR) that is capable of imaging small tumor burdens with minimal background fluorescence in real-time laparoscopic extirpative surgery of small prostate tumor xenografts in murine and porcine models. Results: In a mouse model, we demonstrate the feasibility of using real-time NIR laparoscopic imaging to detect and surgically remove PSMA-positive xenografts. We then validate the use of our laparoscopic real-time NIR imaging system in a large animal model. Our novel light source, which is optimized for YC-27, is capable of detecting as little as 12.4 pg/mL of the compound (2.48-pg YC-27 in 200-μL agarose). Finally, in a mouse xenograft model, we demonstrate that the use of real-time NIR imaging can reduce positive surgical margins (PSM). Conclusions: These data indicate that a NIR-emitting fluorophore targeted to PSMA may allow improved surgical treatment of human prostate cancer, reduce the rate of PSMs, and alleviate the need for adjuvant radiotherapy postoperatively. Clin Cancer Res; 21(4); 771–80. ©2014 AACR.

Objective. To perform a proof of concept microbiome evaluation and PD-L1 expression profiling in clear-cell renal cell carcinoma (cc-RCC) with associated tumor thrombus (TT). Methods. After IRB approval, six patients underwent radical nephrectomy (RN) with venous tumor thrombectomy (VTT). We collected fresh tissue specimens from normal adjacent, tumor, and thrombus tissues. We utilized RNA sequencing to obtain PD-L1 expression profiles and perform microbiome analysis. Statistical assessment was performed using Student’s t-test, chi-square, and spearman rank correlations using SPSS v25. Results. We noted the tumor thrombus to be mostly devoid of diverse microbiota. A large proportion of Staphylococcus epidermidus was detected and unknown if this is a surgical or postsurgical contaminant; however, it was noted more in the thrombus than other tissues. Microbiome diversity profiles were most abundant in the primary tumor compared to the thrombus or normal adjacent tissue. Differential expression of PD-L1 was examined in the tumor thrombus to the normal background tissue and noted three of the six subjects had a threshold above 2-fold. These three similar subjects had foreign microbiota that are typical residents of the oral microbiome. Conclusion. Renal tumors have more diverse microbiomes than normal adjacent tissue. Identification of resident oral microbiome profiles in clear-cell renal cancer with tumor thrombus provides a potential biomarker for thrombus response to PD-L1 inhibition.

To perform immune-cell enumeration and programmed death-ligand 1 (PD-L1) expression in clear cell renal cell carcinoma (cc-RCC) with tumor thrombus (TT) to guide therapeutic decisions. After obtaining IRB approval and surgical consent, 6 patients underwent radical nephrectomy with venous tumor thrombectomy. We utilized RNA Sequencing to obtain RNAseq expression profiles. Computational calculation and enumeration of immune cells were performed using CIBERSORT, xCell, and ingenuity pathway analysis software. Statistical assessment was conducted using a t test, chi-square, ANOVA and Spearman rank correlations using SPSS v21. We observed a higher proportion of M1 macrophages in the primary tumor and tumor thrombus, while we noted no difference in M2 macrophages despite M2 representing a high number in thrombus samples. (ANOVA, P = .032, and P = .89, respectively). Validation with xCell and ingenuity pathway analysis analysis showed a high involvement of macrophages. We observed a higher number of M1 macrophages (CIBERSORT mean 0.11 vs 0.03, P < 0.01) and (nonactivated) resting Natural Killer (NK) cells (0.077 vs 0.017, P = .02) associated PD-L1 high expression of the primary tumor. PDL1 expression was variable without differences in tumor stage, level, or immune cell detection. We observed an inverse correlation of mean platelet volume with PD-L1 expression within the primary tumor (Spearman, -0.89, P = 02) and the TT (Spearman, -0.77, P = 0.07). Renal tumor thrombus has higher levels of M1 macrophages that could be utilized as additional targets for future drug development. The PD-L1 expression on clear cell RCC biopsy may not represent its corresponding TT. Future studies are needed to confirm mean platelet volume as a potential blood-based biomarker for PD-L1 expression in RCC.