Relationship between 18F-FDG accumulation and lactate dehydrogenase A expression in lung adenocarcinomas

Proteome-wide Ligand and Target Discovery by Using Strain-Enabled Cyclopropane Electrophiles

The evolving use of covalent ligands as chemical probes and therapeutic agents could greatly benefit from an expanded array of cysteine-reactive electrophiles for efficient and versatile proteome profiling. Herein, to expand the current repertoire of cysteine-reactive electrophiles, we developed a new class of strain-enabled electrophiles based on cyclopropanes. Proteome profiling has unveiled that C163 of lactate dehydrogenase A (LDHA) and C88 of adhesion regulating molecule 1 (ADRM1) are ligandable residues to modulate the protein functions. Moreover, fragment-based ligand discovery (FBLD) has revealed that one fragment (Y-35) shows strong reactivity toward C66 of thioredoxin domain-containing protein 12 (TXD12), and its covalent binding has been demonstrated to impact its downstream signal pathways. TXD12 plays a pivotal role in enabling Y-35 to exhibit its antisurvival and antiproliferative effects. Finally, dicarbonitrile-cyclopropane has been demonstrated to be an electrophilic warhead in the development of GSTO1-involved dual covalent inhibitors, which is promising to alleviate drug resistance.

Lactate Dehydrogenase A is Associated with Elevated FDG Metabolism, Radioiodine Non-avidity, and Poor Prognosis in Differentiated Thyroid Cancer

RATIONALE AND OBJECTIVES

The role of lactate dehydrogenase A (LDHA) expression in differentiated thyroid cancer (DTC), especially in radioiodine-refractory DTC, remains unclear. The aim of this study was to analyse the relationships and the prognostic value of LDHA, glycolysis, and radioactive iodine (RAI) avidity in DTC.

METHODS

DTC patients who underwent 18F-FDG PET/CT and subsequent total thyroidectomy or metastasectomy were enroled. The expression levels of LDHA, glucose transporters (Glut) and Ki67 proteins in tumour tissue were measured using immunohistochemistry. The maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) of 18F-FDG PET/CT were measured. A radioiodine whole body scan was used to determine lesion radioiodine avidity.

RESULTS

69 patients with DTC were enroled in this study, including 37 women (53.6%) and 32 men (46.4%), with a median age of 52 years (11 to 77 years). Regarding the pathological category, papillary thyroid cancer was documented in 50 patients (72.5%), while follicular and poorly differentiated thyroid cancer were found in 12 patients (17.4%) and seven patients (10.1%), respectively. Distant metastases were observed in 27 (39.1%) patients; 34 (49.3%) were classified as stage I, 16 (23.2%) as stage II, and 3 (4.3%) and 16 (23.2%) patients in stages III and IV, respectively. LDHA expression levels were correlated with Glut3 expression levels (r = 0.395, P = 0.003) and SUVmax (r = 0.408, P = 0.002). The median LDHA expression and lesion SUVmax of the RAI avidity group were lower than those of the non-RAI avidity group (200 vs. 285, P = 0.036; 3.06 vs. 8.38, P = 0.038, respectively). Elevated SUVmax (P = 0.004), MTV (P = 0.014), TLG (P = 0.001) and LDHA expression (P = 0.048) led to shorter time to progression (TTP); Cox regression analysis revealed that TLG (HR: 4.773, P = 0.047) was an independent prognostic factor of TTP.

CONCLUSION

Elevated LDHA is correlated with increased glucose metabolism, decreased radioiodine avidity, and accelerated disease progression. Moreover, 18F-FDG PET/CT acting as "in vivo pathology" is an excellent predictor of DTC prognosis.

The value of dual time-point fluorine-18 fluorodeoxyglucose PET/computed tomography imaging in predicting lymph node metastasis in non-small cell lung cancer patients

OBJECTIVE

The purpose of this study was to analyze the correlation between specified dual time-point fluorine-18 fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) imaging parameters and pathological characteristics in non-small cell lung cancer (NSCLC) patients.

METHODS

This study retrospectively analyzed 47 patients with NSCLC. All patients underwent dual time-point 18F-FDG PET/CT imaging. We obtained the metabolic parameters, standardized uptake value (SUV) maximum, SUVmean, delayed standardized uptake value (DSUV) maximum, DSUVmean, delay index standardized uptake value (DISUV) maximum, and DISUVmean, of the primary tumor. The tumor size was measured by CT. All lymph nodes had a definite pathological diagnosis. We next evaluated the status of the lymph node metastases (LNM) and the correlations between metabolic parameters and clinical characteristics. Receiver operating characteristic curves were drawn for the prediction of LNM.

RESULTS

We found that the DSUVmax, DISUVmax, DSUVmean, and tumor size were significantly related to LNM (P = 0.036, 0.009, and 0.049, respectively). Multivariate analysis revealed that tumor size and DISUVmax were independent risk factors for LNM in lung cancer patients. According to the receiver operating characteristic curve analysis, the optimal cutoff values for DISUVmax and tumor size were 0.33 and 2.8 cm, respectively. When these two parameters were combined, the area under the curve for predicting LNM in NSCLC was 0.768, and the sensitivity was 95.7% for predicting LNM in lung cancer patients. We further allocated the patients to three groups: the high-risk group (tumor size ≥ 2.8 cm, DISUVmax ≥ 0.33), the moderate-risk group (tumor size ≥ 2.8 cm, DISUVmax < 0.33, or tumor size < 2.8 cm, DISUVmax ≥ 0.33), and the low-risk group (tumor size < 2.8 cm, DISUVmax < 0.33). The rates of LNM were 70, 50, and 0%, respectively.

CONCLUSION

Tumor size and DISUVmax are risk factors for predicting LNM, and they are more useful in combination. Compared with standard PET/CT imaging, dual time-point PET/CT imaging has added value in predicting LNM in NSCLC patients.

Tripartite-motif 3 represses ovarian cancer progression by downregulating lactate dehydrogenase A and inhibiting AKT signaling

The E3 ubiquitin ligase Tripartite-motif 3 (TRIM3) is known to play a crucial role in tumor suppression in various tumors through different mechanisms. However, its function and mechanism in ovarian cancer have yet to be elucidated. Our study aims to investigate the expression of TRIM3 in ovarian cancer and evaluate its role in the development of the disease. Our findings revealed a significant decrease in TRIM3 mRNA and protein levels in ovarian cancer tissues and cells when compared to normal ovarian epithelial tissues and cells. Furthermore, we observed a negative correlation between the protein level of TRIM3 and the FIGO stage, as well as a positive correlation with the survival of ovarian cancer patients. Using gain and loss of function experiments, we demonstrated that TRIM3 can inhibit cell proliferation, migration and invasion of the ovarian cancer cells in vitro, as well as suppress tumor growth in vivo. Mechanistic studies showed that TRIM3 interacts with lactate dehydrogenase A, a key enzyme in the glycolytic pathway, through its B-box and coiled-coil domains and induces its ubiquitination and proteasomal degradation, leading to the inhibition of glycolytic ability in ovarian cancer cells. RNA-sequencing analysis revealed significant alterations in the phosphatidylinositol signaling pathways upon TRIM3 overexpression. Additionally, overexpression of TRIM3 inhibited the phosphorylation of AKT. In conclusion, our study demonstrated that TRIM3 exerts a tumor-suppressive effect in ovarian cancer, at least partially, by downregulating LDHA and inhibiting the AKT signaling pathway, and thus leading to the inhibition of glycolysis and limiting the growth of ovarian cancer cells.

Emerging roles of cytosolic phosphoenolpyruvate kinase 1 (PCK1) in cancer

Although it was traditionally believed that gluconeogenesis enzymes were absent from cancers that did not originate in gluconeogenic organs, numerous investigations have shown that they are functionally expressed in a variety of tumors as mediators of shortened forms of Gluconeogenesis. One of the isomers of PEPCK, the first-rate limiting enzyme in gluconeogenesis, is PCK 1, which catalyzes the conversion of oxaloacetate (OAA) and GTP into PEP, CO2, and GDP. It is also known as PEPCK-C or PCK1, and it is cytosolic. Despite being paradoxical, it has been demonstrated that, in addition to its enzymatic role in normal metabolism, this enzyme also plays a role in tumors that arise in gluconeogenic and non-gluconeogenic organs. According to newly available research, it has metabolic and non-metabolic roles in tumor progression and development. Thus, this review will give insight into PCK1 relationship, function, and mechanism in or with different types of cancer using contemporary findings.

Relationship between SUVmax on 18F-FDG PET and PD-L1 expression in hepatocellular carcinoma

PURPOSE

Our study was to investigate the correlation between 18F-FDG uptake in HCC and tumor PD-L1 expression in HCC, and assess the value of 18F-FDG PET/CT imaging for predicting PD-L1 expression in HCC.

METHODS

A total of 102 patients with confirmed HCC were included in this retrospective study. The PD-L1 expression and immune cell infiltrating of tumors were determined through immunohistochemistry staining. The SUVmax of HCC lesions were assessed using 18F-FDG PET/CT. The correlation between PD-L1 expression and the clinicopathological were evaluated by the Cox proportional hazards model and the Kaplan-Meier survival analysis.

RESULTS

The SUVmax of HCC primary tumors was higher in patients with poorly differentiated HCC, large tumor size, portal vein tumor thrombus, lymph node and distant metastases, and death. The SUVmax of HCC are correlated with the PD-L1 expression and the number of cytotoxic T cells and M2 macrophage infiltration. PD-L1 expression was significantly correlated with tumor SUVmax, tumor differentiation, tumor size, portal vein tumor thrombosis, and patient survival status and infiltrating M2 macrophages. Further, our results confirmed that SUVmax, portal vein tumor thrombosis, and the number of infiltrating M2 macrophages were closely related to PD-L1 expression and were independent risk factors by multivariate analysis. The combined assessment of SUVmax values and the presence of portal vein tumor thrombosis by 18F-FDG PET/CT imaging can help determine PD-L1 expression in HCC.

CONCLUSIONS

FDG uptake in HCC was positively correlated with the PD-L1 expression and the number of cytotoxic T cells and M2 macrophage infiltration. The combined use of SUVmax and portal vein tumor thrombosis by PET/CT imaging assess the PD-L1 expression better in HCC. These findings also provide a basis for clinical studies to assess the immune status of tumors by PET/CT.

Relationship between SUVmax on 18F-FDG PET and PD-L1 expression in liver metastasis lesions after colon radical operation

PURPOSE

Our study was to investigate the correlation correlation between FDG uptake and PD-L1 expression of liver metastasis in patients with colon cancer, and to determine the value of FDG-PET in predicting PD-L1 expression in liver metastasis of colon cancer.

METHODS

A total of 72 patients with confirmed liver metastasis of colon cancer were included in this retrospective study. The PD-L1 expression and immune cell infiltrating of tumors were determined through immunohistochemistry staining. The SUVmax of liver metastasis lesions were assessed using ¹⁸ F-FDG PET/CT. The correlation between PD-L1 expression and the clinicopathological were evaluated by the Cox proportional hazards model and the Kaplan-Meier survival analysis.

RESULTS

PD-L1 expression was significantly correlated with FDG uptake (SUVmax), tumor size, differentiation, survival and cytotoxic T cells infiltration in liver metastasis of colon cancer (P < 0.05). And liver metastases with high counts of infiltrating cytotoxic T cells showed greater FDG uptake than those with low counts of infiltrating cytotoxic T cells. The SUVmax of liver metastases and the degree of differentiation of metastases were closely related to PD-L1 expression, and were independent risk factors.The combined assessment of SUVmax values and tthe degree of differentiation of metastase can help determine PD-L1 expression in liver metastasis of colon cancer.

CONCLUSIONS

FDG uptake in liver metastasis of colon cancer was positively correlated with the PD-L1 expression and the number of cytotoxic T cells infiltration. The joint evaluation of two parameters, SUVmax and degree of differentiation, can predict PD-L1 expression in liver metastases.

Prognostic values of ALDOB expression and 18F-FDG PET/CT in hepatocellular carcinoma

Purpose

The glycolytic enzyme fructose 1,6-bisphosphate aldolase B (ALDOB) is aberrantly expressed and impacts the prognosis in hepatocellular carcinoma (HCC). Hepatic ALDOB loss leads to paradoxical upregulation of glucose metabolism, favoring hepatocellular carcinogenesis. Nevertheless, the relationship between ALDOB expression and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake, and their effects on HCC prognosis remain unclear. We evaluated whether ALDOB expression is associated with ¹⁸F-FDG uptake and their impacts on HCC prognosis prediction.

Methods

Changes in ALDOB expression levels and the prognostic values in HCC were analyzed using data from The Cancer Genome Atlas (TCGA) database. Ultimately, 34 patients with HCC who underwent ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) preoperatively were enrolled in this retrospective study. ALDOB expression was determined using immunohistochemistry (IHC) staining, and the maximum standardized uptake value (SUVmax) of HCC was calculated from the ¹⁸F-FDG PET/CT scans. The relationship between ALDOB expression and SUVmax was examined, and their impacts on overall survival were evaluated using Cox proportional hazards models and Kaplan-Meier survival analysis. ALDOB overexpression in HUH7 and 7721 cells was used to analyze its role in tumor metabolism.

Results

According to TCGA database, the ALDOB mRNA level was downregulated in HCC compared to normal tissue, and significantly shortened overall survival in HCC patients. ALDOB protein expression was similarly decreased in IHC findings in HCC than that in adjacent normal tissues (P<0.05) and was significantly associated with tumor size (P<0.001), high tumor-node-metastasis stage (P=0.022), and elevated SUVmax (P=0.009). ALDOB expression in HCC was inversely correlated with SUVmax (r=-0.454; P=0.012), and the optimal SUVmax cutoff value for predicting its expression was 4.15. Prognostically, low ALDOB expression or SUVmax ≥3.9 indicated shorter overall survival time in HCC. Moreover, COX regression analysis suggested high SUVmax as an independent prognostic risk factor for HCC (P=0.036). HCC patients with negative ALDOB expression and positive SUVmax (≥3.9) were correlated with worse prognosis. ALDOB overexpression in HCC cells significantly decreases ¹⁸F-FDG uptake and lactate production.

Conclusion

SUVmax in HCC patients is inversely correlated with ALDOB expression, and ¹⁸F-FDG PET/CT may be useful for ALDOB status prediction. The combined use of ALDOB expression and ¹⁸F-FDG PET/CT data can provide additional information on disease prognosis in HCC patients.

Relationship between standardized uptake value on 18F-FDG PET and PD-L1 expression in clear cell renal cell carcinoma

Purpose

Partial clear cell renal cell carcinoma (CCRCC) may be sensitive to immune checkpoint inhibitor treatment targeting the programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) pathway. Assessing the levels of PD-L1 using non-invasive imaging is useful to select immunotherapy-sensitive patients. Currently, whether PD-L1 levels in CCRCC correlate with 18F fluorodeoxyglucose (18F-FDG) uptake is unknown. This study aimed to assess whether 18F-FDG-positron emission tomography (PET) imaging could be used to infer PD-L1 levels in CCRCC.

Methods

Immunohistochemistry (IHC) was used to assess PD-L1 levels in samples of tumors obtained retrospectively from a cohort of 58 patients with CCRCC who also received 18F-FDG PET/CT imaging. The IHC scores for PD-L1 were compared with the 18F-FDG maximum standardized uptake value (SUVmax), and the mean standardized uptake value (SUVmean) value, with the clinical characteristics of CCRCC, and with the IHC scores of enzymes related to glucose metabolism (glucose transporter type 1 (GLUT1), hexokinase 2 (HK2), lactate dehydrogenase A (LDHA)), and Von Hippel-Lindau tumor suppressor (VHL).

Results

Increased renal venous invasion, lymph node metastasis, tumor size, SUVmean, and SUVmax correlated significantly with higher PD-L1 levels (P &lt; 0.05). The IHC scores of VHL and LDHA correlated positively with those of PD-L1 (P = 0.035, P = 0.011, respectively). Significant correlations between PD-L1 levels and SUVmean and lymph node metastasis were observed upon multivariate analysis. SUVmean combined with lymph node metastasis predicted that 20.59% of the low probability group would express PD-L1, 29.41% of the medium probability group would express PD-L1, and 71.43% of the high probability group would express PD-L1.

Conclusion

The status of lymph node metastasis, SUVmax, and SUVmean of the primary lesion correlated with PD-L1 levels in CCRCC. A combination of lymph node metastasis status and SUVmean could be utilized to predict PD-L1 levels, thus allowing monitoring of a tumor’s immunotherapy response.

Use of F-18 FDG PET/CT Through Delayed Diuretic Imaging for Preoperative Evaluation of Upper Urinary Tract-Occupying Lesions

Purpose

To evaluate the value of F-18 FDG PET/CT in the differentiation of malignant and benign upper urinary tract-occupying lesions.

Patients and Methods

64 patients with upper urinary tract-occupying lesions underwent F-18 FDG PET/CT at RenJi Hospital from January 2015 to February 2019 in this retrospective study. Of the 64 patients, 50 patients received nephroureterectomy or partial ureterectomy; 14 patients received ureteroscopy and biopsy. The comparisons of PET/CT parameters and clinical characteristics between malignant and benign upper urinary tract-occupying lesions were investigated.

Results

Of the 64 patients, 49 were found to have malignant tumors. Receiver operating characteristic analysis determined the lesion SUVmax value of 6.75 as the threshold for predicting malignant tumors. There were significant associations between malignant and benign upper urinary tract-occupying lesions and SUVmax of lesion (P<0.001), lesion size (P<0.001), and patient age (P=0.011). Multivariate analysis showed that SUVmax of lesion (P=0.042) and patient age (P=0.009) as independent predictors for differentiation of malignant from benign upper urinary tract-occupying lesions. There was a significant difference in tumor size between the positive (SUVmax >6.75) and negative (SUVmax ≤6.75) PET groups in 38 of the 49 patients with malignant tumors.

Conclusion

The SUVmax of lesion and patient age is associated with the nature of upper urinary tract-occupying lesions. F-18 FDG PET/CT may be useful to distinguish between malignant and benign upper urinary tract-occupying lesions and determine a suitable therapeutic strategy.

Delayed 18F-FDG PET/CT Appearance of Urachal Adenocarcinomas

Background

Urachal carcinoma is a rare urological malignancy. Use of ¹⁸F-FDG PET/CT in urological oncology has developed slowly because of the urinary elimination of ¹⁸F-FDG. We investigated whether delayed postdiuretic ¹⁸F-FDG PET/CT could be used for diagnosing urachal carcinoma.

Methods

This retrospective study included 6 patients who underwent delayed postdiuretic ¹⁸F-FDG PET/CT for the evaluation of urachal carcinoma. The delayed postdiuretic PET/CT parameters and clinical characteristics of urachal carcinoma were investigated.

Results

There was no significant difference in the SUVmax between the primary tumors and the urine in the bladder before delayed diuresis (25.4 ± 19.5 vs. 42.9 ± 31.1, P=0.18). However, the SUVmax of the primary tumors was significantly higher than the SUVmax of urine after delayed diuresis (25.4 ± 19.5 vs. 3.5 ± 1.6, P=0.002). Diuretic ¹⁸F-FDG PET/CT was positive in all patients when compared with normal liver tissues or urine after delayed diuresis. The SUVmax, TLR, and TUR of the primary tumors were 25.4 (range: 7.2–58.9), 7.0 (range: 1.8–14.7), and 6.8 (range: 3.8–11.3), respectively. Delayed postdiuretic ¹⁸F-FDG PET/CT had a negative predictive value of 100% (5/5) for predicting lymph node metastasis. One patient received chemotherapy after radical resection of urachal carcinoma because ¹⁸F-FDG PET/CT found lung metastases, and one patient only received chemotherapy because PET/CT found peritoneal and skeletal metastases.

Conclusions

Delayed postdiuretic ¹⁸F-FDG PET/CT is a useful tool for the preoperative evaluation of urachal carcinoma. ¹⁸F-FDG PET/CT may improve clinical decision making and management of urachal carcinomas.

Relationship between the expression of oestrogen receptor and progesterone receptor and 18F-FDG uptake in endometrial cancer

Background: Progestogens have been widely used for the treatment of inoperable endometrial cancer or younger patients with endometrial cancer. Identifying markers that are predictive of a response to progestogens is critical for successful therapy. Molecular imaging with ¹⁸F^-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) can provide metabolic phenotypic information of many malignancies. We investigated whether estrogen receptor (ER)/progestogen receptor (PR) status is correlated with ¹⁸F-FDG uptake, and whether ¹⁸F-FDG PET/CT could be useful for predicting ER/PR status in endometrial cancer.

Results: Endometrial cancers in the ER-positive group had lower SUVmax than those in the ER-negative group (12.3 ± 6.2 vs. 19.9 ± 6.6, respectively; P = 0.003). Endometrial cancers in the PR-positive group also had lower SUVmax than those in the PR-negative group (12.4 ± 6.2 vs. 20.0 ± 6.9, respectively; P = 0.005). Multivariate analysis indicated that SUVmax and tumour differentiation grade were significantly associated with both ER and PR status (P = 0.027 and P = 0.044, respectively). ER expression was predicted with an accuracy of 74.2% when a SUVmax value of 15.3 was used as a cutoff point for analysis. Similarly, PR expression was predicted with an accuracy of 74.2%, when a SUVmax value of 15.95 was used as the threshold for analysis.

Conclusion: Higher ¹⁸F-FDG accumulation in endometrial cancers is correlated with negative ER/PR expression. ¹⁸F-FDG PET/CT may be used to predict the status of ER/PR and thus aid in optimal treatment decision in endometrial cancers.

Methods: We carried out a retrospective analysis on 62 endometrial cancer patients who underwent ¹⁸F-FDG PET/CT before radical treatment. The maximum of standardized uptake value (SUVmax) was calculated from the ¹⁸F-FDG accumulation of the primary tumor. The relationship between SUVmax and ER/PR status was analyzed.

Dually Enzyme- and Acid-Triggered Self-Immolative Ketal Glycoside Nanoparticles for Effective Cancer Prodrug Monotherapy

The use of glycoside prodrugs is a promising strategy for developing new targeted medicines for chemotherapy. However, the in vivo utility of such prodrugs is hindered by insufficient activation and the lack of convenient synthetic methods. We have developed an innovative strategy for synthesizing ketal glycoside prodrugs that are unique in being activated by a dual enzyme- and acid-triggered self-immolative mechanism. Amphiphilic glucosyl acetone-based ketal-linked etoposide glycoside prodrug isomers were synthesized and fabricated into excipient-free nanoparticles for effective cancer prodrug monotherapy. Hydrolysis of the glycosidic linkage or the ketal linkage triggered hydrolysis of the other linkage, which resulted in spontaneous self-immolative hydrolysis of the prodrugs. Nanoparticles of the prodrug isomer that was the most labile in a lysosome-mimicking environment displayed high intratumoral accumulation and strong antitumor activity in an A549 xenograft mouse model. Our strategy may be useful for the development of stimulus-responsive self-immolative prodrugs and their nanomedicines.

PD-L1 expression correlation with metabolic parameters of FDG PET/CT and clinicopathological characteristics in non-small cell lung cancer

BACKGROUND

Immunotherapy targeting programmed cell death 1 (PD-1) or its ligand 1 (PD-L1) has shown promising results in non-small cell lung cancer (NSCLC) patients. Exploring PD-L1 expression could help to select NSCLC candidates for immunotherapy. Fluorine-18 fluorodeoxyglucose (FDG) PET/CT could provide phenotypic information on malignant tumors. Thus, this study investigated PD-L1 expression correlation with metabolic parameters of FDG PET/CT and clinicopathological characteristics in NSCLC.

METHODS

FDG PET/CT metabolic parameters including maximum standard uptake (SUVmax), metabolic tumor volume and total lesion glycolysis of primary lesion (MTV-P, TLG-P), and combination of primary lesion and metastases (MTV-C, TLG-C) were compared with PD-L1-positive expression in patients with NSCLC. Moreover, clinicopathological characteristics, including age, gender, smoking history, serum tumor markers, tumor location, size, TNM stage, and genetic mutation were also reviewed.

RESULTS

All 374 patients (215 men; 159 women; age 63 ± 9 years) included 283 adenocarcinomas (ACs) and 91 squamous cell carcinomas (SCCs). PD-L1 expression was positive in 27.8% (104/374) cases. SUVmax, TLG-P, and TLG-C of PD-L1 positivity were significantly higher than PD-L1 negativity. Moreover, PD-L1 expression was obviously correlated with man, smoking, and central NSCLC. If ACs and SCCs were separately analyzed, PD-L1 positivity in ACs and SCCs was 21.6% (61/283) and 47.5% (43/91), respectively, and only SUVmax was obviously associated with PD-L1 expression. Furthermore, multivariate analysis revealed that only SUVmax was an independent predictor of PD-L1 positive expression in overall NSCLC, AC, and SCC. Using a SUVmax cut-off value of 12.5, PD-L1 status of NSCLC was predicted by FDG PET/CT with sensitivity, specificity, and accuracy of 65.4%, 86.7%, and 80.7%, respectively.

CONCLUSIONS

PD-L1 expression of NSCLC was related to SUVmax, TLG, man, smoking, and central location. However, only SUVmax was an independent predictor of PD-L1 positivity, which could help to explore the existence of immune checkpoints.

Delayed post-diuretic 18F-FDG PET/CT for preoperative evaluation of renal pelvic cancer

Background: Application of ¹⁸F^-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in urological oncology was relatively slowly due to the urinary elimination of ¹⁸F-FDG. We investigated whether delayed post-diuretic ¹⁸F-FDG PET/CT could be used for diagnosing renal pelvic cancer.

Methods: 51 patients were included who underwent delayed post-diuretic ¹⁸F-FDG PET/CT for detecting renal pelvic space-occupying lesions. The comparations of delayed PET/CT parameters and clinical characteristics between renal pelvic cancer and benign polyp were investigated.

Results: Among the 51 patients, 47 were found to have renal pelvic urothelial carcinoma, and 4 had benign polyp. ROC analysis identified the lesion maximum standardized uptake value (SUVmax) of 6.2 as the optimal cut-off value to distinguish from renal pelvic urothelial carcinoma to benign polyp. With the SUVmax cut-off of 6.2, the sensitivity, and specificity for predicting of renal pelvic urothelial carcinoma were 91.5% (43/47), and 100% (4/4). We also found a significant difference in tumor size between the positive (SUVmax > 6.2) and negative (SUVmax ≤ 6.2) PET groups in renal pelvic cancers. In patients with tumor size < 1.1 cm, the probability of being in the negative PET group was 75%. In such patients, a substantial proportion of renal pelvic cancer demonstrated negative SUVmax similar to that in patients with benign polyp.

Conclusion: Delayed ¹⁸F-FDG PET/CT could be used for differentiating renal pelvic cancer from benign polyp. In patients with small tumor size, renal pelvic cancer may present low ¹⁸F-FDG uptake, mimicking the metabolic phenotypes of patients with benign polyp.

18F-fluorodeoxyglucose positron emission tomography correlates with tumor immunometabolic phenotypes in resected lung cancer

Enhanced tumor glycolytic activity is a mechanism by which tumors induce an immunosuppressive environment to resist adoptive T cell therapy; therefore, methods of assessing intratumoral glycolytic activity are of considerable clinical interest. In this study, we characterized the relationships among tumor ¹⁸F-fluorodeoxyglucose (FDG) retention, tumor metabolic and immune phenotypes, and survival in patients with resected non-small cell lung cancer (NSCLC). We retrospectively analyzed tumor preoperative positron emission tomography (PET) ¹⁸F-FDG uptake in 59 resected NSCLCs and investigated correlations between PET parameters (SUV_Max, SUV_Total, SUV_Mean, TLG), tumor expression of glycolysis- and immune-related genes, and tumor-associated immune cell densities that were quantified by immunohistochemistry. Tumor glycolysis-associated immune gene signatures were analyzed for associations with survival outcomes. We found that each ¹⁸F-FDG PET parameter was positively correlated with tumor expression of glycolysis-related genes. Elevated ¹⁸F-FDG SUV_Max was more discriminatory of glycolysis-associated changes in tumor immune phenotypes than other ¹⁸F-FDG PET parameters. Increased SUV_Max was associated with multiple immune factors characteristic of an immunosuppressive and poorly immune infiltrated tumor microenvironment, including elevated PD-L1 expression, reduced CD57⁺ cell density, and increased T cell exhaustion gene signature. Elevated SUV_Max identified immune-related transcriptomic signatures that were associated with enhanced tumor glycolytic gene expression and poor clinical outcomes. Our results suggest that ¹⁸F-FDG SUV_Max has potential value as a noninvasive, clinical indicator of tumor immunometabolic phenotypes in patients with resectable NSCLC and warrants investigation as a potential predictor of therapeutic response to immune-based treatment strategies.

PCK1 Regulates Glycolysis and Tumor Progression in Clear Cell Renal Cell Carcinoma Through LDHA

Background

Suppressed gluconeogenesis and increased glycolysis are common in clear cell renal cell carcinoma (ccRCC). Phosphoenolpyruvate carboxykinase 1 (PCK1) is a rate-limiting gluconeogenesis enzyme. However, the role of PCK1 in tumor metabolism and progression remains unclear.

Methods

Artificial modulation of PCK1 (down- and upregulation) in two ccRCC cell lines was performed to explore the role of PCK1 in the glycolytic phenotype and in tumor growth and metastasis in vitro and in vivo. Sixty-two patients with ccRCC underwent ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography. The levels of PCK1 and lactate dehydrogenase A (LDHA) in ccRCC tissues and peritumor tissues were investigated with immunohistochemistry. The relationships between ¹⁸F-FDG accumulation and the expression of PCK1 and LDHA were analyzed. The mechanisms underlying the regulation of LDHA by PCK1 were analyzed using in vitro molecular techniques.

Results

PCK1 suppressed ccRCC cell growth and metastasis in vitro and inhibited tumorigenesis in nude mice by blocking the aerobic glycolysis pathway. Clinically, low levels of PCK1 expression were associated with poor prognosis in patients with ccRCC. The expression level of PCK1 was negatively correlated with tumor progression, the LDHA expression level and ¹⁸F-FDG accumulation in primary ccRCC tissue. We also demonstrated that PCK1 reduces the stability of LDHA through posttranslational regulation. Finally, we showed that the effects of PCK1 on glucose metabolism, cell proliferation and metastasis are mediated via the inhibition of LDHA.

Conclusion

Our study identified a novel molecular mechanism underlying the Warburg effect. PCK1 may serve as a candidate prognostic biomarker, and targeting the PCK1/LDHA pathway might be a new strategy to selectively inhibit tumor metabolism in human ccRCC.

Preoperative evaluation of residual tumor in patients with endometrial carcinoma by using 18F-FDG PET/CT

Purpose: To evaluate the value of ¹⁸F-FDG positron emission tomography (PET)/computed tomography (CT) for determining the presence of residual tumors after curettage in patients with endometrial cancer. Methods: Preoperative ¹⁸F-FDG PET/CT was performed in 90 women with endometrial cancer. PET/CT parameters and clinical characteristics were compared between patients with and without residual tumors. The clinical characteristics of patients with residual tumors that showed low ¹⁸F-FDG uptake were also analyzed. Results: Among the 90 patients, 86 had residual tumors. ROC analysis identified a lesion SUVmax value of 5.0 as the optimal cut-off value for predicting whether or not patients had a residual tumor. With the SUVmax cut-off of 5, the sensitivity, specificity, positive predictive value, and negative predictive values for residual tumor prediction were 87.2%, 100%, 100%, and 26.7%, respectively. Univariate analysis showed significant associations between the high PET group (SUVmax > 5) and low PET group (SUVmax ≤ 5), and histologic type (P = 0.043) and tumor size (P < 0.001) in patients with residual tumors. In patients with low-grade and clear cell carcinomas and a tumor size < 1.35 cm, the probability of being in the low-PET group was 47.6%. In such patients, major parts of the residual tumors showed low ¹⁸F-FDG uptake, similar to that in patients with no residual tumors. Conclusion: SUVmax was the lone predictive value for the presence of residual tumors after curettage in patients with endometrial cancer. Lesion SUVmax greater than 5 suggested a high possibility of residual tumors. In patients with low-grade and clear cell carcinomas with tumor size < 1.35 cm, residual tumors may present low ¹⁸F-FDG uptake, mimicking the metabolic phenotypes of patients without residual tumors.

Correlation Between von Hippel-Lindau Gene Expression and Tumor SUVmax and Survival Prognosis in Hepatocellular Carcinoma

Background

We investigated the relationship between the 18F-FDG PET/CT metabolic parameter SUVmax in primary hepatocellular carcinoma (HCC) and expression of von Hippel-Lindau (VHL), as well as its effect on HCC survival prognosis.

Material/Methods

We retrospectively analyzed data for 62 HCC patients who received 18F-FDG PET/CT before surgery at the First Affiliated Hospital of Bengbu Medical College from June 2013 to June 2018 (42 males, 20 females; median age 62 years). No treatment was performed prior to the examination. The relationship between preoperative 18F-FDG PET/CT metabolic parameters, clinical pathology, and disease prognosis was analyzed.

Results

SUVmax was significantly different in varying HCC pathological grades, and with tumor length, lymph node metastasis, portal vein tumor thrombus, and distant metastasis (p<0.05). SUVmax was significantly higher in the shorter patient survival group (p<0.05). 18F-FDG uptake was correlated with expression of glucose transporter 1 and VHL in tumor tissues (correlation coefficients 0.476 and 0.565, respectively; both p<0.05). Negative expression of VHL suggested poor tumor differentiation and poor prognosis, but no correlation was observed with patient age, sex, tumor length, lymph node metastasis, or distant metastasis. The survival time of patients with low VHL expression was significantly shorter than that of patients with positive VHL expression (p=0.02).

Conclusions

VHL expression in primary HCC has a significant correlation with SUVmax, and negative VHL expression predicts a worse clinical prognosis.

Relationship between PD-L1 expression and 18F-FDG uptake in gastric cancer

PURPOSE

Immunotherapy has been successfully utilized for treatment of gastric cancer, so the identification of clinicopathologic features that are predictive of response to this therapy is crucial. ¹⁸F-FDG PET/CT can provide information on the molecular phenotype of many malignant tumors. The correlation between ¹⁸F-FDG accumulation and PD-L1/PD-L1-TILs status in gastric cancer patients has not been investigated. The aim of the current study is to assess whether ¹⁸F-FDG accumulation is associated with PD-L1/PD-L1-TILs status, and whether ¹⁸F-FDG PET/CT may be useful for predicting PD-L1/PD-L1-TILs expression of gastric cancer.

RESULTS

Tumors with positive PD-L1 expression had higher SUVmax than in tumors with negative PD-L1 expression (15.0 ± 8.0 vs. 7.2 ± 4.2, respectively; P = 0.004). Tumors with positive PD-L1-TILs expression also had higher SUVmax than in tumors with negative PD-L1-TILs expression (10.3 ± 6.5 vs. 6.6 ± 3.7, respectively; P = 0.034). Multivariate analysis suggested that SUVmax remained significantly correlated with the status of PD-L1 (P = 0.043) and PD-L1-TILs (P = 0.016). PD-L1 expression was predicted with an accuracy of 67.2% when a SUVmax value of 8.55 was used as a cutoff point for analysis. Similarly, PD-L1-TILs expression was predicted with an accuracy of 64.2%, when a SUVmax value of 7.9 was used as the threshold for analysis.

CONCLUSION

Higher ¹⁸F-FDG accumulation in gastric cancers is correlated with positive PD-L1/PD-L1-TILs expression. ¹⁸F-FDG PET/CT may be used to predict the status of PD-L1/PD-L1-TILs and thus aid in optimal treatment decision.

METHODS

A retrospective analysis was conducted on 64 patients with gastric cancer who underwent ¹⁸F-FDG PET/CT. SUVmax was calculated from the ¹⁸F-FDG accumulation of the primary tumor. The relationship between SUVmax and PD-L1/PD-L1-TILs status was analyzed.

Effect of IDH3a on glucose uptake in lung adenocarcinoma: A pilot study based on [18 F]FDG

Subunit of isocitrate dehydrogenase 3 (IDH3a) as upstream of the hypoxia-inducible factor was reported highly expressed in malignant tumors, playing an important role in glucose metabolism reprogramming. As one of rate-limiting enzyme in the Krebs cycle, whether high expression of IDH3a affects glucose uptake in tumors has not been elucidated. This study was aimed to investigate the relationship between IDH3a expression and tumor glucose uptake. Sixty-five patients who underwent 2-[18 F]-2-deoxy-D-glucose ([18 F]-FDG) positron emission tomography/computed tomography (PET/CT) imaging before surgery and pathologically diagnosed as lung adenocarcinoma were included. All patients were divided into high (n = 31) and low (n = 34) groups according IDH3a expression by immunohistochemistry. Comparatively higher [18 F]-FDG uptake was found in high IDH3a expression group. Glucose transporter 1 (GLUT1) level was demonstrated to correlate with IDH3a expression, but not for hexokinase 2 (HK2). Furthermore, A549 and H1299 cells experiment showed, the expression of p-AKT and GLUT1 were significantly downregulated after IDH3a interference. The cellular uptake of [18 F]-FDG and lactate production were significantly reduced in treatment group. In summary, high expression of IDH3a in lung adenocarcinoma patients is associated with higher glucose uptake. IDH3a targets AKT-GLUT1 pathway to affect glucose uptake and metabolites in lung adenocarcinoma.

Roles of GLUT-1 and HK-II expression in the biological behavior of head and neck cancer

The Warburg effect plays an important role in the proliferation and invasion of malignant tumors. Glucose transporter 1 and hexokinase II are two key energy transporters involved in mediating the Warburg effect. This review will analyze the mechanisms of these two markers in their effects on the biological behavior of head and neck cancer.

Protein kinase CK2-dependent aerobic glycolysis-induced lactate dehydrogenase A enhances the migration and invasion of cancer cells

We investigated the intracellular metabolic fluxes of protein kinase CK2-activating (Cα OE) cells and role of lactate dehydrogenase A (LDHA) as a contributor of tumorigenesis after reprogrammed glucose metabolism. Facilitated aerobic glycolysis was confirmed via isotope tracer analysis, in which ¹³C₆-Glc or ¹³C₅-Gln was added to the media, following which metabolites converted from Cα OE cells were identified. We found a greater decrease in cell survival, colony-forming ability, migration, and Cα OE cell invasion under glucose (Glc)-depletion conditions than under glutamine (Gln)-depletion conditions. Cancer cell migration and invasion increased due to LDHA elevation of the altered metabolic axis driven by activated CK2. FX11 treatment and LDHA knockdown suppressed migration and invasion through ROS generation, but this was partially reversed by the antioxidant N-acetylcysteine (NAC). Moreover, LDHA inhibition decreased tumor growth in a mouse xenograft model transplanted with Cα OE cells. Finally, we concluded that LDHA is an excellent metabolic target for tumor therapy, based on CK2α derived aerobic glycolysis.

L-Lactate dehydrogenase B may be a predictive marker for sensitivity to anti-EGFR monoclonal antibodies in colorectal cancer cell lines

Recently, proteins derived from cancer cells have been widely investigated as biomarkers for predicting the efficacy of chemotherapy. In this study, to identify a sensitive biomarker for the efficacy of anti-epidermal growth factor receptor monoclonal antibodies (anti-EGFR mAbs), proteins derived from 6 colorectal cancer (CRC) cell lines with different sensitivities to cetuximab, an anti-EGFR mAb, were analyzed. Cytoplasmic and membrane proteins extracted from each CRC cell line were digested using trypsin and analyzed comprehensively using mass spectrometry. As a result, 148 and 146 peaks from cytoplasmic proteins and 363 and 267 peaks from membrane proteins were extracted as specific peaks for cetuximab-resistant and -sensitive CRC cell lines, respectively. By analyzing the proteins identified from the peptide peaks, cytoplasmic L-lactate dehydrogenase B (LDHB) was detected as a marker of cetuximab sensitivity, and it was confirmed that LDHB expression was increased in cetuximab-resistant CRC cell lines. Furthermore, LDHB expression levels were significantly upregulated with the acquisition of resistance to cetuximab in cetuximab-sensitive CRC cell lines. In conclusion, LDHB was identified as an important factor affecting cetuximab sensitivity using comprehensive proteome analysis for the first time.

The Role of Lactate Metabolism in Prostate Cancer Progression and Metastases Revealed by Dual-Agent Hyperpolarized 13C MRSI

This study applied a dual-agent, ¹³C-pyruvate and ¹³C-urea, hyperpolarized ¹³C magnetic resonance spectroscopic imaging (MRSI) and multi-parametric (mp) ¹H magnetic resonance imaging (MRI) approach in the transgenic adenocarcinoma of mouse prostate (TRAMP) model to investigate changes in tumor perfusion and lactate metabolism during prostate cancer development, progression and metastases, and after lactate dehydrogenase-A (LDHA) knock-out. An increased Warburg effect, as measured by an elevated hyperpolarized (HP) Lactate/Pyruvate (Lac/Pyr) ratio, and associated Ldha expression and LDH activity were significantly higher in high- versus low-grade TRAMP tumors and normal prostates. The hypoxic tumor microenvironment in high-grade tumors, as measured by significantly decreased HP ¹³C-urea perfusion and increased PIM staining, played a key role in increasing lactate production through increased Hif1α and then Ldha expression. Increased lactate induced Mct4 expression and an acidic tumor microenvironment that provided a potential mechanism for the observed high rate of lymph node (86%) and liver (33%) metastases. The Ldha knockdown in the triple-transgenic mouse model of prostate cancer resulted in a significant reduction in HP Lac/Pyr, which preceded a reduction in tumor volume or apparent water diffusion coefficient (ADC). The Ldha gene knockdown significantly reduced primary tumor growth and reduced lymph node and visceral metastases. These data suggested a metabolic transformation from low- to high-grade prostate cancer including an increased Warburg effect, decreased perfusion, and increased metastatic potential. Moreover, these data suggested that LDH activity and lactate are required for tumor progression. The lactate metabolism changes during prostate cancer provided the motivation for applying hyperpolarized ¹³C MRSI to detect aggressive disease at diagnosis and predict early therapeutic response.

Uptake mechanism of metabolic-targeted gold nanoparticles

AIM

To elucidate the interactions, uptake mechanisms and cytotoxicity profile of glucose-functionalized gold nanoparticles (2GF-GNPs), for expanding and advancing the recently proposed technology of metabolic-based cancer detection to a variety of cancer diseases.

METHODS

Several cell types with different metabolic features were used to assess the involvement of GLUT-1 and different endocytosis pathways in 2GF-GNP uptake, and the cytotoxicity profile of 2GF-GNPs.

RESULTS

Cellular uptake of 2GF-GNP strongly correlated with GLUT-1 surface expression, and occurred mainly through clathrin-mediated endocytosis. 2GF-GNPs showed no toxic effect on cell cycle and proliferation.

CONCLUSION

These findings promote development of metabolic-based cancer detection technologies, and suggest that 2GF-GNPs may enable specific cancer detection in a wide range of tumors characterized by high GLUT-1 expression.

Artificial nutrition in patients with cancer has no impact on tumour glucose metabolism: Results of the PETANC Study

BACKGROUND & AIMS

Nutrition support is recommended in cachexic patients with cancer. However, there is no clear evidence about its impact on tumour growth. Glycolysis, which is usually higher in cancer than normal cells, can be monitored by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) imaging that is widely used for cancer staging and therapy efficacy assessment. Here, we used ¹⁸F-FDG PET/CT imaging to investigate whether artificial nutrition has an impact on tumour glucose metabolism in patients with cancer and cachexia.

METHODS

This prospective study included ten patients with histologically proven head and neck or oesophageal cancer. All patients underwent ¹⁸F-FDG PET/CT imaging at baseline and after (parenteral and/or enteral) nutrition support on average for 7 days. Tumour glucose metabolism changes were evaluated using static (SUV_max, SUV_mean and SUL_peak) and dynamic (glucose metabolic rate and transport constant rates, k) parameters computed from the ¹⁸F-FDG PET/CT data.

RESULTS

Artificial nutrition (median energy intake of 21.83 kcal/kg/day [13.16-45.90], protein intake of 0.84 g/kg/day [0.56-1.64]) was administered. Eight patients (80%) received enteral nutrition and two patients (20%) parenteral support. Comparison of ¹⁸F-FDG PET/CT parameters did not highlight any significant difference in tumour glucose metabolism before and after the period of nutrition support.

CONCLUSIONS

In cachexic patients with head and neck or oesophageal cancer, nutrition support administered according to the current guidelines shows no impact on tumour glucose metabolism, assessed by ¹⁸F-FDG PET/CT.

Antitumor activity of intratracheal inhalation of temozolomide (TMZ) loaded into gold nanoparticles and/or liposomes against urethane-induced lung cancer in BALB/c mice

The current study aimed to develop gold nanoparticles (GNPs) and liposome-embedded gold nanoparticles (LGNPs) as drug carriers for temozolomide (TMZ) and investigate the possible therapeutic effects of intratracheal inhalation of nanoformulation of TMZ-loaded gold nanoparticles (TGNPs) and liposome-embedded TGNPs (LTGNPs) against urethane-induced lung cancer in BALB/c mice. Physicochemical characters and zeta potential studies for gold nanoparticles (GNPs) and liposome-embedded gold nanoparticles (LGNPs) were performed. The current study was conducted by inducing lung cancer chemically via repeated exposure to urethane in BALB/C mice. GNPs and LGNPs were exhibited in uniform spherical shape with adequate dispersion stability. GNPs and LGNPs showed no significant changes in comparison to control group with high safety profile, while TGNPs and LTGNPs succeed to improve all biochemical data and histological patterns. GNPs and LGNPs are promising drug carriers and succeeded in the delivery of small and efficient dose of temozolomide in treatment lung cancer. Antitumor activity was pronounced in animal-treated LTGNPs, these effects may be due to synergistic effects resulted from combination of temozolomide and gold nanoparticles and liposomes that may improve the drug distribution and penetration.

miR-449a Suppresses LDHA-Mediated Glycolysis to Enhance the Sensitivity of Non-Small Cell Lung Cancer Cells to Ionizing Radiation

MicroRNA dysregulation contributes to malignant progression, dissemination, and profound treatment resistance in multiple cancers. miR-449a is recognized as a tumor suppresser. However, the roles of miR-449a in lung cancer initiation and progression are largely unknown. Our study aims to investigate the roles and underlying mechanism of miR-449a in modulating sensitivity to ionizing radiation (IR) in non-small cell lung cancer (NSCLC). Lung cancer cells were transfected with miR-449a mimics or negative control and exposed to IR; the levels of target protein, glycolysis, cell viability, apoptosis, and DNA damage were examined. miR-449a was suppressed in lung cancer tissues and cancer cells (A549 and H1299). IR exposure significantly increased the expression of miR-449a in A549 cells at doses ranging from 4 to 8 Gy at 24 h, whereas no significant change in miR-449a was found in H1299 cells after IR. When A549 cells were exposed to IR at a dose of 8 Gy, the miR-449a level only had an acute increase within 12 h. miR-449a restoration dramatically suppressed IR-induced cell apoptosis and DNA damage in both A549 and H1299 cells. Bioinformatics analysis indicated that lactate dehydrogenase A (LDHA) was a potential target of miR-449a. miR-449a mimic transfection substantially suppressed the LDHA expression and production of lactate catalyzed by LDHA as well as glucose uptake. We confirmed that miR-449a could bind to the 3'-UTR of LDHA mRNA using luciferase reporter assay. LDHA siRNA-transfected cells showed enhanced cell apoptosis and DNA damage in response to IR exposure. miR-449a upregulation enhanced IR sensitivity of lung cancer cells by suppressing LDHA and the subsequent glycolysis.

Lactate dehydrogenase A promotes the invasion and proliferation of pituitary adenoma

Lactate dehydrogenase A (LDHA) has been reported to be involved in the initiation and progression of tumors. However, the potential role of LDHA in pituitary adenoma (PA) remains unknown. In this study, we showed that the expression levels of LDHA mRNA and protein were significantly elevated in invasive PA samples, and positively correlated with higher Ki-67 index. Overexpression of LDHA in a PA cell line (GH3) promoted glucose uptake through the upregulation of glucose transporter-1 (Glut1), lactate secretion and induced cellular invasion by upregulation of matrix metalloproteinase2 (MMP2). LDHA also promoted GH3 cell proliferation through induction of cell cycle progression via activation of the Akt-GSK-3β-cyclinD1 pathway. Accordingly, oxamate-induced inhibition of LDHA suppressed glucose uptake, lactate secretion, invasion and proliferation in GH3 cells via down regulation of Glut1 and MMP2 expression and inhibition of the Akt-GSK-3β-cyclinD1 pathway. Moreover, oxamate induced GH3 cell apoptosis by increasing mitochondrial reactive oxygen species (ROS) generation. In vivo, LDHA overexpression promoted tumor growth, and oxamate delayed tumor growth. In primary PA cell cultures, oxamate also effectively suppressed invasion and proliferation. Our data indicate that LDHA is involved in promoting the progression of PA, and oxamate might be a promising therapeutic agent for the treatment of PA.

Stable shRNA Silencing of Lactate Dehydrogenase A (LDHA) in Human MDA-MB-231 Breast Cancer Cells Fails to Alter Lactic Acid Production, Glycolytic Activity, ATP or Survival

BACKGROUND

In the US, African Americans have a high death rate from triple-negative breast cancer (TNBC), characterized by lack of hormone receptors (ER, PR, HER2/ERRB2) which are otherwise valuable targets of chemotherapy. There is a need to identify novel targets that negatively impact TNBC tumorigenesis. TNBCs release an abundance of lactic acid, under normoxic, hypoxic and hyperoxic conditions; this referred to as the Warburg effect. Accumulated lactic acid sustains peri-cellular acidity which propels metastatic invasion and malignant aggressive transformation. The source of lactic acid is believed to be via conversion of pyruvate by lactate dehydrogenase (LDH) in the last step of glycolysis, with most studies focusing on the LDHA isoform.

MATERIALS AND METHODS

In this study, LDHA was silenced using long-term MISSION® shRNA lentivirus in human breast cancer MDA-MB-231 cells. Down-regulation of LDHA transcription and protein expression was confirmed by western blot, immunocytochemistry and qPCR. A number of parameters were measured in fully viable vector controls versus knock-down (KD) clones, including levels of lactic acid produced, glucose consumed, ATP and basic metabolic rates.

RESULTS

The data show that lentivirus V-165 generated a knock-down clone most effective in reducing both gene and protein levels to less than 1% of vector controls. Stable KD showed absolutely no changes in cell viability, lactic acid production, ATP, glucose consumption or basic metabolic rate. Given the complete absence of impact on any observed parameter by LDH-A KD and this being somewhat contrary to findings in the literature, further analysis was required to determine why. Whole-transcriptome analytic profile on MDA-MB-231 for LDH subtypes using Agilent Human Genome 4×44k microarrays, where the data show the following component breakdown. Transcripts: 30.47 % LDHA, 69.36% LDHB, 0.12% LDHC and 0.05% LDHD.

CONCLUSION

These findings underscore the importance of alternative isoforms of LDH in cancer cells to produce lactic acid, when LDHA is silenced or inhibited. LDHA silencing alone is not effective in hampering or inducing changes in survival, metabolism or lactic acid produced in a cell line with high concentrations of LDHB. Future research will be required to confirm effects of dual LDHA/B knockdown and further confirm that the sole source of lactic acid produced occurs through LDH (all isoforms) in breast cancer cells.

Suppression of pyruvate dehydrogenase kinase-2 re-sensitizes paclitaxel-resistant human lung cancer cells to paclitaxel

Despite impressive initial clinical responses, the majority of lung cancer patients treated with paclitaxel eventually develop resistance to the drug. Pyruvate dehydrogenase kinase-2 (PDK2) is a key regulator of glycolysis and oxidative phosphorylation, and its expression is increased in a variety of tumors. In this study, the role of PDK2 in mediating paclitaxel resistance in lung cancer cells was investigated using biochemical and isotopic tracing methods. Increased expression of PDK2 was observed in paclitaxel-resistant cells ascompared totheir parental cells. Down-regulation of PDK2 usingsiRNA increased the sensitivity to paclitaxel of resistant lung cancer cells. Targeting paclitaxel-resistant cells throughPDK2 knockdown was associated with reduced glycolysis rather than increased oxidative phosphorylation (OXPHOS). Moreover, combining paclitaxel withthe specific PDK2 inhibitor dichloroacetate had a synergistic inhibitory effect on the viability of paclitaxel-resistant lung cancer cells. These results indicate that paclitaxel-induced expression of PDK2 serves as an important mechanism for acquired paclitaxel resistance of lung cancer cells. They also highlight the importance of PDK2 for potential therapeutic interventions in patients who have developed a resistance to paclitaxel.

Mechanisms underlying 18F-fluorodeoxyglucose accumulation in colorectal cancer

Positron emission tomography (PET) with ¹⁸F-fluorodeoxyglucose (FDG) is a diagnostic tool to evaluate metabolic activity by measuring accumulation of FDG, an analogue of glucose, and has been widely used for detecting small tumors, monitoring treatment response and predicting patients’ prognosis in a variety of cancers. However, the molecular mechanism of FDG accumulation into tumors remains to be investigated. It is well-known that most cancers are metabolically active with elevated glucose metabolism, a phenomenon known as the Warburg effect. The underlying mechanisms for elevated glucose metabolism in cancer tissues are complex. Recent reports have indicated the potential of FDG-PET/CT scans in predicting mutational status (e.g., KRAS gene mutation) of colorectal cancer (CRC), which suggests that FDG-PET/CT scans may play a key role in determining therapeutic strategies by non-invasively predicting treatment response to anti-epidermal growth factor receptor (EGFR) therapy. In this review, we summarize the current findings investigating the molecular mechanism of ¹⁸F-FDG accumulation in CRC.

Functional Effects of Cigarette Smoke-Induced Changes in Airway Smooth Muscle Mitochondrial Morphology

Long-term exposure to cigarette smoke (CS) triggers airway hyperreactivity and remodeling, effects that involve airway smooth muscle (ASM). We previously showed that CS destabilizes the networked morphology of mitochondria in human ASM by regulating the expression of mitochondrial fission and fusion proteins via multiple signaling mechanisms. Emerging data link regulation of mitochondrial morphology to cellular structure and function. We hypothesized that CS-induced changes in ASM mitochondrial morphology detrimentally affect mitochondrial function, leading to CS effects on contractility and remodeling. Here, ASM cells were exposed to 1% cigarette smoke extract (CSE) for 48 h to alter mitochondrial fission/fusion, or by inhibiting the fission protein Drp1 or the fusion protein Mfn2. Mitochondrial function was assessed via changes in bioenergetics or altered rates of proliferation and apoptosis. Our results indicate that both exposure to CS and inhibition of mitochondrial fission/fusion proteins affect mitochondrial function (i.e., energy metabolism, proliferation, and apoptosis) in ASM cells. In vivo, the airways in mice chronically exposed to CS are thickened and fibrotic, and the expression of proteins involved in mitochondrial function is dramatically altered in the ASM of these mice. We conclude that CS-induced changes in mitochondrial morphology (fission/fusion balance) correlate with mitochondrial function, and thus may control ASM proliferation, which plays a central role in airway health. J. Cell. Physiol. 232: 1053-1068, 2017. © 2016 Wiley Periodicals, Inc.

Relationship Between 18F-FDG PET/CT Findings and HER2 Expression in Gastric Cancer

(18)F-FDG PET has been widely used in the management of malignant tumors. In gastric cancer, the status of human epidermal growth factor receptor 2 (HER2) predicts the response to anti-HER2 antibody therapy, and testing of HER2 expression is now routine in the management of gastric cancer patients. However, to date, the relationship between (18)F-FDG uptake and HER2 expression has not, to our knowledge, been investigated. In this study, we aimed to investigate whether HER2 expression is associated with (18)F-FDG uptake and whether (18)F-FDG PET/CT can be used to predict the HER2 status of gastric cancer.

METHODS

A retrospective analysis was performed on 64 gastric cancer patients who had undergone (18)F-FDG PET/CT before surgical resection. Tumor SUVmax was calculated from the level of (18)F-FDG uptake.

RESULTS

No significant correlation was found between SUVmax and HER2 expression in gastric cancer. However, when signet-ring cell carcinoma was excluded, SUVmax was significantly higher in the HER2-negative group than in the HER2-positive group (8.619 ± 5.878 vs. 3.789 ± 2.613, respectively; P = 0.021). Multivariate analysis indicated that SUVmax and tumor differentiation remained significantly associated with HER2 expression (P = 0.048 and P = 0.028, respectively). HER2 expression was predicted with an accuracy of 64.4% when an SUVmax cutoff of 6.2 was used.

CONCLUSION

(18)F-FDG uptake by gastric cancer is associated with HER2 expression. (18)F-FDG PET/CT may be useful for predicting the HER2 status of gastric cancer and for determining the therapeutic strategy.

Imaging of Tumor Metabolism Using Positron Emission Tomography (PET)

Molecular imaging employing PET/CT enables in vivo visualization, characterization, and measurement of biologic processes in tumors at a molecular and cellular level. Using specific metabolic tracers, information about the integrated function of multiple transporters and enzymes involved in tumor metabolic pathways can be depicted, and the tracers can be directly applied as biomarkers of tumor biology. In this review, we discuss the role of F-18-fluorodeoxyglucose (FDG) as an in vivo glycolytic marker which reflects alterations of glucose metabolism in cancer cells. This functional molecular imaging technique offers a complementary approach to anatomic imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) and has found widespread application as a diagnostic modality in oncology to monitor tumor biology, optimize the therapeutic management, and guide patient care. Moreover, emerging methods for PET imaging of further biologic processes relevant to cancer are reviewed, with a focus on tumor hypoxia and aberrant tumor perfusion. Hypoxic tumors are associated with poor disease control and increased resistance to cytotoxic and radiation treatment. In vivo imaging of hypoxia, perfusion, and mismatch of metabolism and perfusion has the potential to identify specific features of tumor microenvironment associated with poor treatment outcome and, thus, contribute to personalized treatment approaches.

Clinicopathologic Features and Molecular Characteristics of Glucose Metabolism Contributing to ¹⁸F-fluorodeoxyglucose Uptake in Gastrointestinal Stromal Tumors

Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) is useful in the preoperative diagnosis of gastrointestinal stromal tumors (GISTs); however, the molecular characteristics of glucose metabolism of GIST are unknown. We evaluated 18F-FDG uptake on preoperative PET/CT of 40 patients and analyzed the expression of glycolytic enzymes in resected GIST tissues by qRT-PCR, western blotting, and immunohistochemistry. Results of receiver operating characteristic curve analysis showed that the maximum standardized uptake value (SUVmax) cut-off value of 4.99 had a sensitivity of 89.5%, specificity was 76.2%, and accuracy of 82.5% for identifying tumors with a high risk of malignancy. We found that 18F-FDG uptake correlated positively with tumor size, risk grade, and expression levels of glucose transporter 1 (GLUT1), hexokinase 1 (HK1), and lactate dehydrogenase A (LDHA). Elevated HK and LDH activity was found in high-risk tumors. Among the isoforms of GLUT and HK, GLUT1 and HK1 expression increased with higher tumor risk grade. In addition, overexpression of glycolytic enzymes M2 isoform of pyruvate kinase (PKM2) and LDHA was observed in GISTs, especially in high-risk tumors. These results suggest that upregulation of GLUT1, HK1, PKM2, and LDHA may play an important role in GIST tumorigenesis and may be useful in the preoperative prediction of malignant potential.

Knockdown of PKM2 Suppresses Tumor Growth and Invasion in Lung Adenocarcinoma

Accumulating evidence shows that activity of the pyruvate kinase M2 (PKM2) isoform is closely related to tumorigenesis. In this study, we investigated the relationship between PKM2 expression, tumor invasion, and the prognosis of patients with lung adenocarcinoma. We retrospectively analyzed 65 cases of patients with lung adenocarcinoma who were divided into low and a high expression groups based on PKM2 immunohistochemical staining. High PKM2 expression was significantly associated with reduced patient survival. We used small interfering RNA (siRNA) technology to investigate the effect of targeted PKM2-knockout on tumor growth at the cellular level. In vitro, siRNA-mediated PKM2-knockdown significantly inhibited the proliferation, glucose uptake (25%), ATP generation (20%) and fatty acid synthesis of A549 cells, while the mitochondrial respiratory capacity of the cells increased (13%).Western blotting analysis showed that PKM2-knockout significantly inhibited the expression of the glucose transporter GLUT1 and ATP citrate lyase, which is critical for fatty acid synthesis. Further Western blotting analysis showed that PKM2-knockdown inhibited the expression of matrix metalloproteinase 2 (MMP-2) and vascular endothelial growth factor (VEGF), which are important in degradation of the extracellular matrix and angiogenesis, respectively. These observations show that PKM2 activates both glycolysis and lipid synthesis, thereby regulating cell proliferation and invasion. This information is important in elucidating the mechanisms by which PKM2 influences the growth and metastasis of lung adenocarcinoma at the cellular and molecular level, thereby providing the basic data required for the development of PKM2-targeted gene therapy.

Low Expression of LDHB Correlates With Unfavorable Survival in Hepatocellular Carcinoma: Strobe-Compliant Article

Lactate dehydrogenase B (LDHB) is widely expressed in adult somatic tissue and plays important roles in the development of human cancers. However, the association between LDHB expression and the clinicopathological characteristics of hepatocellular carcinoma (HCC) is not well understood. The study was to detect the expression of LDHB in human HCC and investigate the association between its expression and the clinicopathological characteristics of HCC. Immunohistochemistry (IHC) analysis was performed to characterize the expression of LDHB in HCC and matched noncancerous tissues. Kaplan-Meier survival and Cox regression analyses were employed to evaluate the prognosis of 75 HCC patients. The results showed that the expression of LDHB in HCC was significantly lower than that in noncancerous tissues. Moreover, the expression level of the LDHB protein in HCC was correlated with pathological grade (P = 0.037), vascular invasion (P = 0.037), lymph node metastasis (P = 0.016), and tumor-node metastasis (TNM) stage (P = 0.007). Cox regression analysis further revealed that LDHB expression is an independent prognostic factor for disease-free survival (P = 0.045) and overall survival (P = 0.019).These data are the first to indicate that LDHB expression is a valuable prognostic biomarker for HCC and that low LDHB expression suggests unfavorable survival outcomes in HCC patients.

Dichloroacetate restores drug sensitivity in paclitaxel-resistant cells by inducing citric acid accumulation

BACKGROUND

The Warburg effect describes the increased reliance of tumor cells on glycolysis for ATP generation. Mitochondrial respiratory defect is thought to be an important factor leading to the Warburg effect in some types of tumor cells. Consequently, there is growing interest in developing anti-cancer drugs that target mitochondria. One example is dichloroacetate (DCA) that stimulates mitochondria through inhibition of pyruvate dehydrogenase kinase.

METHODS

We investigated the anti-cancer activity of DCA using biochemical and isotopic tracing methods.

RESULTS

We observed that paclitaxel-resistant cells contained decreased levels of citric acid and sustained mitochondrial respiratory defect. DCA specifically acted on cells with mitochondrial respiratory defect to reverse paclitaxel resistance. DCA could not effectively activate oxidative respiration in drug-resistant cells, but induced higher levels of citrate accumulation, which led to inhibition of glycolysis and inactivation of P-glycoprotein.

CONCLUSIONS

The abilityof DCA to target cells with mitochondrial respiratory defect and restore paclitaxel sensitivity by inducing citrate accumulation supports further preclinical development.