Involvement of platelets in tumor cell metastasis

Platelet Indices in Colorectal Cancer Patients with Synchronous Liver Metastases

Aims

Liver metastases occur in approximately 25% of colorectal cancer (CRC) patients and cause more than 90% of deaths in CRC. Platelets play a crucial role in cancer progression and metastases. We aimed to investigate the relationship between platelet indices and CRC with synchronous liver metastases.

Methods

We conducted a retrospective clinical study including 206 CRC patients without metastases and 200 CRC patients with synchronous liver metastases from January 1, 2015, to December 31, 2017. Data of the patients' clinicopathological characteristics were collected.

Results

Platelet distribution width (PDW) was decreased in CRC patients with liver metastases compared with CRC patients without liver metastases. In addition, the prevalence of liver metastases reduced as PDW quartiles increased. After adjusting for other risk factors, the odds ratios (95% confidence intervals) for CRC liver metastases according to PDW quartiles were 1.000, 0.289 (0.156-0.535), 0.482 (0.271-0.860), and 0.190 (0.101-0.358).

Conclusions

Compared with CRC patients without metastases, PDW is reduced in CRC patients with liver metastases. Moreover, PDW was independently associated with the presence of CRC liver metastases.

Radiation-Induced Changes in Tumor Vessels and Microenvironment Contribute to Therapeutic Resistance in Glioblastoma

Glioblastoma (GBM) is a largely fatal and highly angiogenic malignancy with a median patient survival of just over 1 year with radiotherapy (RT). The effects of RT on GBM remain unclear, although increasing evidence suggests that RT-induced alterations in the brain microenvironment affect the recurrence and aggressiveness of GBM. Glioma stem cells (GSCs) in GBM are resistant to conventional therapies, including RT. This study aimed to investigate the effect of radiation on tumor growth and the GSC microenvironment in a mouse model of glioma. To evaluate the growth-inhibitory effects of ionizing radiation on GSCs, tumor volume was measured via anatomical magnetic resonance imaging (MRI) after the intracranial injection of 1 × 10⁴ human patient-derived GSCs (83NS cells), which exhibit marked radioresistance. When a tumor mass of ~5 mm³ was detected in each animal, 10 Gy of cranial irradiation was administered. Tumor progression was observed in the orthotopic xenografted GSC tumor (primary tumor) from a detectable tumor mass (5 mm³) to a lethal tumor mass (78 mm³) in ~7 d in the non-irradiated group. In the RT group, tumor growth was halted for almost 2 weeks after administering 10 Gy cranial irradiation, with tumor growth resuming thereafter and eventually approaching a lethal mass (56 mm³) 21 d after radiation. Radiation therapy yielded good therapeutic effects, with a 2-fold increase in GSC glioma survival; however, tumor relapse after RT resulted in higher mortality for the mice with a smaller tumor volume (p = 0.029) than the non-irradiated tumor-bearing mice. Moreover, tumor regrowth after IR resulted in different phenotypes associated with glioma aggressiveness compared with the non-irradiated mice; the apparent diffusion coefficient by diffusion MRI decreased significantly (p < 0.05, 0 Gy vs. 10 Gy) alongside decreased angiogenesis, abnormal vascular dilatation, and upregulated CD34, VWF, AQP1, and AQP4 expression in the tumor. These findings demonstrate that radiation affects GSCs in GBM, potentially resulting in therapeutic resistance by changing the tumor microenvironment. Thus, the results of this study suggest potential therapeutic targets for overcoming the resistance of GBMs to RT.

Prognostic Values of Platelet-Associated Indicators in Resectable Cervical Cancer

Background:

Cervical cancer is one of the leading causes of cancer mortality in women, which seriously threatens the health of women worldwide. Platelet (PLT)-related parameters, including PLT count, mean platelet volume (MPV), plateletcrit (PCT), and platelet distribution width (PDW), are correlated with tumor prognosis.

Methods:

In total, 110 patients with cervical carcinoma were recruited in this study. The patients were divided into 2 groups according to the receiver operating characteristic analysis cutoff values of PLT, MPV, PCT, or PDW. The post-/preradiotherapy ratios were defined as the rate of preradiotherapy PLT-related parameters counts and the corresponding ones obtained after radiotherapy.

Results:

Higher pretreatment PLT level was correlated with Higher Federation of Gynecology and Obstetrics (FIGO) stage (II). Higher pretreatment PLT level was correlated with worse progression-free survival (PFS) and overall survival (OS). Increased post-/preradiotherapy ratio of PLT was correlated with worse PFS and OS. Changes in PCT, MPV, or PDW levels had no effects on PFS or OS. Cox regression analysis model indicated that larger tumor size, higher pretreatment PLT level, and increased post-/preradiotherapy PLT ratio were independently associated with worse PFS; higher FIGO stage (II) and increased post-/preradiotherapy PLT ratio were independently associated with worse OS.

Conclusion:

Pretreatment PLT level and increased post-/preradiotherapy PLT ratio are correlated with outcomes of cervical cancer.

Alterations in platelet secretion differentially affect thrombosis and hemostasis

We genetically manipulated the major platelet vesicle-associated membrane proteins (VAMP2, VAMP3, and VAMP8) to create mice with varying degrees of disrupted platelet secretion. As previously shown, loss of VAMP8 reduced granule secretion, and this defect was exacerbated by further deletion of VAMP2 and VAMP3. VAMP2^Δ3^Δ8^-/- platelets also had reduced VAMP7. Loss of VAMP2 and VAMP3 (VAMP2^Δ3^Δ) had a minimal impact on secretion when VAMP7 and VAMP8 were present. Integrin αIIbβ3 activation and aggregation were not affected, although spreading was reduced in VAMP2^Δ3^Δ8^-/- platelets. Using these mice as tools, we asked how much secretion is needed for proper thrombosis and hemostasis in vivo. VAMP2^Δ3^Δ mice showed no deficiency, whereas VAMP8^-/- mice had attenuated formation of occlusive thrombi upon FeCl₃-induced arterial injury but no excessive bleeding upon tail transection. VAMP2^Δ3^Δ8^-/- mice bled profusely and failed to form occlusive thrombi. Plasma-coagulation factors were normal in all of the strains, but phosphatidylserine exposure was reduced in VAMP2^Δ3^Δ and VAMP2^Δ3^Δ8^-/- platelets. From our data, an ∼40% to 50% reduction in platelet secretion in vitro (dense and α granule) correlated with reduced occlusive thrombosis but no compromise in hemostasis. At a >50% reduction, thrombosis and hemostasis were defective in vivo. Our studies are the first systematic manipulation of platelet exocytic machinery to demonstrate a quantitative linkage between in vitro platelet secretion and hemostasis and thrombosis in vivo. The animals described will be invaluable tools for future investigations into how platelet secretion affects other vascular processes.

Tumor-derived exosomes, myeloid-derived suppressor cells, and tumor microenvironment

Plenty of immune cells infiltrate into the tumor microenvironment (TME) during tumor progression, in which myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of immature myeloid cells with immunosuppressive activity. Tumor cells and stromal cells facilitate the activation and expansion of MDSCs in TME via intercellular communication, and expanded MDSCs suppress anti-tumor immune responses through direct and indirect mechanisms. Currently, exosomes, which are a kind of extracellular vesicles (EVs) that can convey functional components, are demonstrated to participate in the local and distal intercellular communication between cells. Numerous studies have supposed that tumor-derived exosomes (TEXs), whose assembly and release can be modulated by TME, are capable of modulating the cell biology of MDSCs, including facilitating their activation, promoting the expansion, and enhancing the immunosuppressive function. Therefore, in this review, we mainly focus on the role of TEXs in the cell-cell communication between tumor cells and MDSCs, and discuss their clinical applications.

Platelet-secreted CCL3 and its receptor CCR5 promote invasive and migratory abilities of anaplastic thyroid carcinoma cells via MMP-1

Platelet counts have been reported to be closely related to distant metastasis of many malignant tumors. Our previous study showed that elevated peripheral blood platelet counts may be an adverse prognostic factor of anaplastic thyroid carcinoma (ATC) patients, indicating that platelets may promote ATC progression. In the present study, we aimed to identify the role of platelets in ATC cell invasion and migration and to explore the underlying mechanisms. We found that platelets can promote the invasive and migratory of ATC cells, which may be related to the interaction between activated platelet-secreted chemokine (C-C motif) ligand 3 (CCL3) and its receptor CCR5. The interaction was shown to induce the upregulation of matrix metalloproteinase (MMP)-1 via NF-κB pathway. These findings could provide a new idea for the research of targeted platelets to inhibit tumor metastasis.

Limiting tumor seeding as a therapeutic approach for metastatic disease

Here we propose that therapeutic targeting of circulating tumor cells (CTCs), which are widely understood to be the seeds of metastasis, would represent an effective strategy towards limiting numerical expansion of secondary lesions and containing overall tumor burden in cancer patients. However, the molecular mediators of tumor seeding have not been well characterized. This is in part due to the limited number of pre-clinical in vivo approaches that appropriately interrogate the mechanisms by which cancer cells home to arresting organs. It is critical that we continue to investigate the mediators of tumor seeding as it is evident that the ability of CTCs to colonize in distant sites is what drives disease progression even after the primary tumor has been ablated by local modalities. In addition to slowing disease progression, containing metastatic spread by impeding tumor cell seeding may also provide a clinical benefit by increasing the duration of the residence of CTCs in systemic circulation thereby increasing their exposure to pharmacological agents commonly used in the treatment of patients such as chemotherapy and immunotherapies. In this review we will examine the current state of knowledge about the mechanisms of tumor cells seeding as well as explore how targeting this stage of metastatic spreading may provide therapeutic benefit to patients with advanced disease.

Thrombocytopenia: A prognostic factor for hepatocellular carcinoma patients with portal vein tumor thrombus after hepatectomy

BACKGROUND AND AIM

Portal vein tumor thrombus (PVTT) predicts a poor prognosis in hepatocellular carcinoma (HCC) patients. Platelets (PLTs) play an important role in HCC progression and metastasis. However, the relationship between PLTs and PVTT remains unclear. This study aimed to evaluate the value of PLT counts in the prognosis of HCC patients with PVTT after hepatectomy.

METHODS

From January 2002 to December 2012, 694 HCC patients with PVTT after hepatectomy were evaluated. The patients were divided into the thrombocytopenia group (PLT < 100 × 10⁹ /L), the normal group, and the thrombocytosis group (PLT > 300 × 10⁹ /L) based on the preoperative PLT level. A propensity score matching (PSM) analysis was used.

RESULTS

Before the PSM, PVTT patients with thrombocytopenia exhibited longer recurrence-free survival (RFS) and overall survival (OS) compared with those with normal PLT counts (both P < 0.001) or thrombocytosis (P = 0.008 and P = 0.046). For the thrombocytopenia group and the normal group, the 1-, 2-, and 3-year RFS values were 30.0%, 17.6%, and 15.7% and were 10.8%, 6.6%, and 5.8% (P < 0.001), respectively; the 1-, 2-, and 3-year OS values were 61.9%, 37.9%, and 31.2% and were 38.3%, 23.3%, and 16.0% (P < 0.001), respectively. After the PSM, the median survival time was 16.6 versus 8.6 months (P < 0.002) in the two groups. A subgroup analysis revealed that thrombocytopenia is associated with improved OS in those with type I PVTT (P = 0.021) or type II PVTT (P = 0.029).

CONCLUSION

According to the PSM, preoperative thrombocytopenia predicts an increased RFS and OS in HCC patients with PVTT after hepatectomy.

Blocking podoplanin suppresses growth and pulmonary metastasis of human malignant melanoma

Background

Podoplanin (PDPN), a transmembrane O-glycoprotein, is up-regulated in many tumors and is involved in tumor metastasis and malignant progression. In previous studies, we generated a functional blocking monoclonal antibody (mAb, SZ168) against the extracellular domain of human PDPN. This study is aimed to investigate whether blocking PDPN by SZ168 inhibits tumor growth and metastasis.

Methods

Malignant melanoma xenograft model by inoculating subcutaneously human malignant melanoma cell line C8161 into the back of BALB/c nude mice was used. Endogenous PDPN expression in C8161 cells and nasopharyngeal cancer cell line CNE-2 was detected using western blot and flow cytometry.

Results

SZ168 significantly inhibited C8161 or CNE-2 cell-induced platelet aggregation in a dose-dependent manner with a maximal inhibition of 73.9 ± 3.0% in C8161 cells or 77.1 ± 2.7% in CNE-2 cells. Moreover, SZ168 inhibited the growth and pulmonary metastasis of C8161cells in vivo. The number of lung metastatic foci in the SZ168-treated group was significantly decreased compared with that in the control mouse IgG group (1.61 ± 0.44 vs.3.83 ± 0.60, P < 0.01). Subcutaneous tumor volume, weight, and incidence were also significantly reduced in the SZ168-treated group compared to the control group (P < 0.05). Additionally, SZ168 recognized PDPN in immunohistochemical analyses of tumor tissue sections.

Conclusions

SZ168 blocks growth and pulmonary metastasis of human malignant melanoma by inhibiting the interaction between tumor PDPN and platelet CLEC-2 and therefore is a promising antibody for therapeutic development against malignant melanoma.

Super-resolution microscopy can identify specific protein distribution patterns in platelets incubated with cancer cells

Protein contents in platelets are frequently changed upon tumor development and metastasis. However, how cancer cells can influence protein-selective redistribution and release within platelets, thereby promoting tumor development, remains largely elusive. With fluorescence-based super-resolution stimulated emission depletion (STED) imaging we reveal how specific proteins, implicated in tumor progression and metastasis, re-distribute within platelets, when subject to soluble activators (thrombin, adenosine diphosphate and thromboxane A2), and when incubated with cancer (MCF-7, MDA-MB-231, EFO21) or non-cancer cells (184A1, MCF10A). Upon cancer cell incubation, the cell-adhesion protein P-selectin was found to re-distribute into circular nano-structures, consistent with accumulation into the membrane of protein-storing alpha-granules within the platelets. These changes were to a significantly lesser extent, if at all, found in platelets incubated with normal cells, or in platelets subject to soluble platelet activators. From these patterns, we developed a classification procedure, whereby platelets exposed to cancer cells, to non-cancer cells, soluble activators, as well as non-activated platelets all could be identified in an automatic, objective manner. We demonstrate that STED imaging, in contrast to electron and confocal microscopy, has the necessary spatial resolution and labelling efficiency to identify protein distribution patterns in platelets and can resolve how they specifically change upon different activations. Combined with image analyses of specific protein distribution patterns within the platelets, STED imaging can thus have a role in future platelet-based cancer diagnostics and therapeutic monitoring. The presented approach can also bring further clarity into fundamental mechanisms for cancer cell-platelet interactions, and into non-contact cell-to-cell interactions in general.

Preoperative mean platelet volume predicts survival in breast cancer patients with type 2 diabetes

PURPOSE

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of breast cancer (BC). Furthermore, growing evidence suggests that activated platelets play a crucial role in tumor and T2DM. Mean platelet volume (MPV) is a platelet index and is altered in patients with malignancies. The aim of this study was to determine whether preoperative MPV could predict survival in BC patients with T2DM.

METHODS

The clinical data of 266 female BC patients with T2DM and 264 female BC patients without T2DM between January 2011 and December 2011 in our center were retrospectively analyzed. Survival analysis was performed using the log-rank test and Cox proportional hazards regression analysis.

RESULTS

The patients with T2DM had higher MPV levels than the patients without T2DM. Furthermore, MPV was found to be significantly associated with differentiation T2DM from non-T2DM. In addition, survival analysis revealed that the disease-specific survival and overall survival of patients with MPV ≤ 8.0 fL were significantly shorter than that of those with MPV > 8.0 fL in diabetic patients. Multivariate analysis identified MPV as an independent poor prognostic factor for survival only in patients with T2DM not in patients without T2DM.

CONCLUSIONS

Our study first established a connection between MPV and BC patients with T2DM, suggesting that MPV was an independent prognostic factor and could be the biomarker for prognosis.

Mean platelet volume predicts survival in patients with hepatocellular carcinoma and type 2 diabetes

BACKGROUND

Patients with hepatocellular carcinoma (HCC) having pre-existing type 2 diabetes (T2DM) have a poorer prognosis than those without T2DM. Moreover, accumulating evidence reveals that activated platelets play a crucial role in tumor and T2DM. The mean platelet volume (MPV) indicates platelet activation and is altered in malignancies. The present study aimed to investigate the clinical significance of MPV in patients with HCC having T2DM.

METHODS

This retrospective study performed between January 2010 and December 2013 included 331 patients with HCC (165 with T2DM and 166 without T2DM). The overall survival was compared, and the predictors of overall survival were analyzed.

RESULTS

The patients with T2DM had lower MPV levels than those without T2DM. Furthermore, the MPV levels significantly differentiated T2DM from non-T2DM. In addition, for patients with T2DM, the overall survival was significantly shorter in patients with low MPV levels than in those with high MPV levels. Multivariate analysis identified decreased MPV as an independent prognostic factor for overall survival only in patients with T2DM, but not in those without T2DM.

CONCLUSION

Reduced MPV was a prognostic factor for poor outcome in patients with HCC and T2DM.

Combination of Preoperative D-Dimer and Platelet Distribution width Predicts Postoperative Deep Venous Thrombosis in Patients with Cervical Carcinoma

Background: Deep venous thrombosis (DVT) is associated with severe morbidity and mortality in cancer. Platelet distribution width (PDW), a platelet index, indicates variation in platelet size. We aimed to investigate whether the combination of D-dimer and PDW could have a better performance in predicting DVT in patients with cervical carcinoma. Materials and Methods: In 198 consecutive cervical carcinoma patients without preoperative DVT, preoperative D-dimer and PDW levels were measured. Compression ultrasonography was performed in all cervical carcinoma patients before surgery, as well as one month, three months, six months, and 12 months. Results: During a median period of 12 months, 17 of the 198 patients (8.6 %) developed DVT. PDW levels were reduced and D-dimer levels were increased in patients with DVT events compared to those without DVT. Multivariate Cox analysis revealed that both PDW and D-dimer were independent predictors for DVT events. The area under the ROC curve was 0.628 (95% CI: 0.556 to 0.695, p=0.142) when D-dimer was used alone, whereas it increased to 0.777 (95% CI: 0.712 to 0.833, p<0.011) with the addition of PDW. Incorporation of PDW into the D-dimer model significantly improved the predictive value. Conclusions: The combination of preoperative D-dimer and PDW improves the predictive power of postoperative DVT risk in patients with cervical carcinoma.

Baseline platelet counts and derived inflammatory biomarkers: prognostic relevance in metastatic melanoma patients receiving Endostar plus dacarbazine and cisplatin

Background: The clinical efficacy and safety of Endostar combined with chemotherapy in the treatment of metastatic malignant melanoma (MM) were analyzed and the indicators capable of predicting the efficacy of the regimen were identified to guide clinical practice. Patients and methods: The clinical data of 55 patients with metastatic MM without gene mutations who were treated with Endostar combined with dacarbazine and cisplatin were retrospectively analyzed. Efficacy was assessed using RECIST 1.1, and adverse events (AEs) were graded according to NCI-CTCAE 4.0. The log-rank test was used to compare the survival curves of patients in different subgroups, and stepwise multivariate Cox regression analysis was used to determine significant prognostic factors. Differences were considered statistically significant at P<0.05. Results: Of the 55 patients, seven showed a partial response, 20 showed stable disease, and 28 showed progressive disease. The median progression-free survival was 17.9 months. AEs were controllable. Univariate analysis identified biotherapy, clinical stage, clinical classification, low baseline platelet count, platelet to albumin ratio (PAR), and platelet to globulin ratio (PGR) as factors affecting drug efficacy. Multivariate Cox regression analysis identified clinical stage and PAR as independent factors predicting the efficacy of the regimen. Conclusions: Endostar combined with chemotherapy showed a curative effect on metastatic MM without gene mutations, and AEs were controllable. The baseline platelet count and derived PAR and PGR values were associated with the efficacy of the regimen. The potential value of efficacy prediction remains to be further verified by prospective random experiments.

A novel scoring system based on hemostatic parameters predicts the prognosis of patients with advanced pancreatic cancer

OBJECTIVE

The aim of this study was to evaluate the prognostic value of pre-treatment plasma hemostatic parameters in patients with advanced pancreatic cancer.

METHODS

A total of 320 patients diagnosed with advanced pancreatic cancer between January 1, 2011 to December 31, 2015 were enrolled in this retrospective study. The prognostic significance of hemostatic parameters such as prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FBG), platelet count (PLT), mean platelet volume (MPV), plateletcrit (PCT), and platelet distribution width (PDW) was determined by univariate and multivariate Cox hazard models. Then, Kaplan-Meier methods and log-rank tests were performed to compare the survival of patients in different risk groups.

RESULT

Univariate and multivariate analyses showed that prolonged PT, high FBG, and high MPV were independent prognostic factors for poor overall survival (PT > 11.3 s, HR = 1.46, 95%CI = 1.10-1.94, p = 0.009; FBG>2.5 g/L, HR = 1.41, 95%CI = 1.08-1.84, p = 0.011; MPV>12.2 fL, HR = 1.52, 95%CI = 1.13-2.04, p = 0.005). Moreover, all the patients were stratified into three groups by a scoring system based on these three hemostatic markers. The median survival time of the three groups was 8.8 months, 6.3 months and 4.3 months (P < 0.001).

CONCLUSION

PT, FBG and MPV were independent prognostic factors in advanced pancreatic cancer. A novel scoring system based on these hemostatic parameters could be used to predict the survival of patients with advanced pancreatic cancer.

Preoperative platelet distribution width predicts breast cancer survival

BACKGROUND

Breast cancer is one of the most commonly diagnosed cancers, and the fourth leading cause of cancer deaths in females worldwide. Activated platelets play a key role in tumor growth and tumor metastasis. Platelet distribution width (PDW) is a platelet index, and is altered in patients with malignancies. The aim of this study was to explore whether PDW can effectively predict death outcome of breast cancer patients.

STUDY DESIGN

The clinical data of 271 breast cancer patients in our hospital between January 2009 and December 2009 were retrospectively analyzed. Survival analysis was performed using the log-rank test and Cox proportional hazards regression analysis.

RESULT

There were significant correlations between increased PDW and tumor size, molecular subtype, differentiation grade, and cancer stages (T, N, or TNM). Moreover, survival analysis revealed that the overall survival of patients with PDW > 16.8%, which was significantly shorter than those with PDW ⩽ 16.8%. Multivariate analysis indicated that PDW > 16.8% predicts a poor overall survival of breast cancer patients.

CONCLUSIONS

Elevated PDW may serve as a marker of adverse prognosis in breast cancer. However, these data are preliminary and should be interpreted with caution pending validation by additional clinical and molecular/genomics studies in various populations.

Critical evaluation of platelet size as a prognostic biomarker in colorectal cancer across multiple treatment settings: a retrospective cohort study

PURPOSE

The role of mean platelet volume (MPV) as a predictor of outcomes in various cancer entities including colorectal cancer (CRC) has already been analyzed. However, data on the prognostic and predictive value of MPV in CRC over multiple lines of systemic therapy are missing.

METHODS

In this retrospective single-center cohort study, 690 patients with UICC stage II, III or IV CRC receiving adjuvant and/or palliative chemotherapy were included. Primary endpoints in the adjuvant, palliative and best supportive care (BSC) setting were 3-year recurrence-free survival (RFS), 6-months progression-free survival (PFS), and 6-months overall survival (OS), respectively. Kaplan-Meier estimators, log-rank tests, and uni- and multivariable Cox models were used to analyze RFS, PFS and OS. A cut-off defining patients with low MPV was chosen empirically at the 25th percentile of the MPV distribution in the respective treatment setting.

RESULTS

Three-year RFS was 76%. Median 6-month PFS estimates in 1st, 2nd and 3rd line therapy were 59, 37 and 27%, respectively. Median 6-month OS in BSC was 31%. Small platelets as indicated by low MPV did not predict for shorter RFS. In the first 3 palliative treatment lines a consistent association between low MPV and decreased 6-month PFS was not observed. In the BSC setting, patients with low MPV had numerically but not significantly shorter OS. Higher MPV levels did not consistently predict for ORR or DCR across the first 3 palliative treatment lines.

CONCLUSION

Small platelets are not predicting CRC outcomes, and thus are hardly useful for influencing clinical decision making.

Interaction of Treponema pallidum, the syphilis spirochete, with human platelets

Extracellular bacteria that spread via the vasculature employ invasive mechanisms that mirror those of metastatic tumor cells, including intravasation into the bloodstream and survival during hematogenous dissemination, arrestation despite blood flow, and extravasation into distant tissue sites. Several invasive bacteria have been shown to exploit normal platelet function during infection. Due to their inherent ability to interact with and influence other cell types, platelets play a critical role in alteration of endothelial barrier permeability, and their role in cancer metastasis has been well established. The highly invasive bacterium and causative agent of syphilis, Treponema pallidum subspecies pallidum, readily crosses the endothelial, blood-brain and placental barriers. However, the mechanisms underlying this unusual and important aspect of T. pallidum pathogenesis are incompletely understood. In this study we use darkfield microscopy in combination with flow cytometry to establish that T. pallidum interacts with platelets. We also investigate the dynamics of this interaction and show T. pallidum is able to activate platelets and preferentially interacts with activated platelets. Platelet-interacting treponemes consistently exhibit altered kinematic (movement) parameters compared to free treponemes, and T. pallidum-platelet interactions are reversible. This study provides insight into host cell interactions at play during T. pallidum infection and suggests that T. pallidum may exploit platelet function to aid in establishment of disseminated infection.

Thrombin Generation and Cancer: Contributors and Consequences

The high occurrence of cancer-associated thrombosis is associated with elevated thrombin generation. Tumour cells increase the potential for thrombin generation both directly, through the expression and release of procoagulant factors, and indirectly, through signals that activate other cell types (including platelets, leukocytes and erythrocytes). Furthermore, cancer treatments can worsen these effects. Coagulation factors, including tissue factor, and inhibitors of coagulation are altered and extracellular vesicles (EVs), which can promote and support thrombin generation, are released by tumour and other cells. Some phosphatidylserine-expressing platelet subsets and platelet-derived EVs provide the surface required for the assembly of coagulation factors essential for thrombin generation in vivo. This review will explore the causes of increased thrombin production in cancer, and the availability and utility of tests and biomarkers. Increased thrombin production not only increases blood coagulation, but also promotes tumour growth and metastasis and as a consequence, thrombin and its contributors present opportunities for treatment of cancer-associated thrombosis and cancer itself.

Pretreatment thrombocytosis predict poor prognosis in patients with endometrial carcinoma: a systematic review and meta-analysis

BACKGROUND

Several previous studies have confirmed that thrombocytosis was related to reduced survival in many solid tumors. However, the prognostic significance of thrombocytosis in endometrial carcinoma (EC) was still controversy. Therefore, we conducted this study to assess the prognostic value of thrombocytosis in EC.

METHODS

The database including PubMed, MEDLINE, EMBASE, and Web of Science was searched to explore available literature. Above all, the hazard ratio (HR), odds ratios (OR) with 95% confidence intervals (CIs) was used to investigate the correlation between thrombocytosis and overall survival (OS) and disease-free survival (DFS). Moreover, the association between thrombocytosis and patient clinicopathological characteristics was explored. Publication bias and sensitivity analysis also were conducted in this study.

RESULTS

Overall, 11 studies involving 3439 patients were contained in this study. The results revealed that pretreatment thrombocytosis was significantly related to a decreased OS (pooled HR = 2.99; 95% CI = 2.35-3.8; P < 0.001) and DFS (pooled HR = 2.86; 95% CI = 2.27-3.6; P <  0.001) in patients with EC. Moreover, thrombocytosis was correlated with adverse clinicopathological parameters.

CONCLUSIONS

Pretreatment thrombocytosis is an adverse prognostic marker in patients with EC.

TRAIL inhibits platelet-induced colorectal cancer cell invasion

Objective

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a pro-apoptotic ligand that activates the extrinsic apoptosis pathway of cell death receptors. This study aimed to evaluate the relationship between TRAIL and platelet-induced tumor metastasis in colorectal cancer.

Methods

Platelet P-selectin (CD62P) was measured by immunohistochemistry in tumor and adjacent normal tissues from 90 patients with colorectal cancer undergoing resection. Tumor cell invasion was assessed by transwell assay in the presence of platelets with or without TRAIL. The expression of TRAIL receptors DR4 and DR5 on platelets was assessed by flow cytometry, real-time polymerase chain reaction, and western blotting.

Results

P-selectin (CD62P) expression was significantly increased in tumor tissues compared with adjacent normal tissues. High CD62P expression was significantly correlated with tumor stage and vascular invasion. Tumor cell migration was increased by coculture with platelets, but this effect was inhibited by TRAIL. Transforming growth factor (TGF)-β1 secretion was significantly reduced in TRAIL-treated platelets. The TRAIL receptor DR5 but not DR4 was expressed in platelets according to flow cytometry.

Conclusions

TRAIL could inhibit metastasis and colon cancer cell invasion by promoting platelet apoptosis and reducing the release of TGF-β1.

Is use of vitamin K antagonists associated with the risk of prostate cancer?: A meta-analysis

BACKGROUND

Vitamin K antagonists (VKAs) may have potential antitumor effects in prostate cancer. However, the findings of observational studies are inconsistent. The purpose of the present study was to estimate the quantitative association between VKAs use and prostate cancer risk by combining the results of all eligible observational studies.

METHODS

PubMed and Web of Science database were searched from inception until May, 2018. A DerSimonian random-effects model was used to combine the studies. Study heterogeneity was measured using the chi-squared and I statistics.

RESULTS

Six eligible studies were eventually included in our meta-analysis. There was an inverse but not statistically significant association between ever use of VKAs and the risk of prostate cancer (relative risk [RR] 0.84, 95% confidence interval [CI] 0.70-1.01, P = .063) with large heterogeneity across studies (P < .001 for heterogeneity, I = 94.6%). When analysis restricted to long term of VKAs user (>3 years), the pooled risk estimate was 0.83 (0.77-0.90) without obvious heterogeneity (P = .597, I = 0.0%).

CONCLUSION

This meta-analysis indicates that VKAs use may be associated with a decreased risk of prostate cancer, especially in long-term users.

Platelets enhance the ability of bone-marrow mesenchymal stem cells to promote cancer metastasis

Background

Bone marrow-derived mesenchymal stem cells (BM-MSCs) have been identified to be closely associated with cancer progression. Our previous experimental results showed that BM-MSCs promote tumor growth and metastasis of gastric cancer through paracrine-soluble cytokines or exosomes. However, the elements that affect the role of BM-MSCs in promoting tumor metastasis are not clear. It is known that thrombocytosis in cancer patients is very common. Recently, platelets are recognized to play a critical role in tumor progression.

Purpose

This study aims to observe the effect of BM-MSCs which were co-cultured with platelets on tumor cell metastasis.

Methods

Platelet aggregation rate and the expression of P-selectin of platelets co-incubated with conditioned medium of SGC-7901 cells and BM-MSCs were detected by flow cytometry and platelet aggregometer. We also analyzed the change of BM-MSCs after co-incubation with platelets or platelets which were treated with SGC-7901 cells using transwell assay and Western blot analysis. The proliferation and migration ability and expression of VEGF, c-Myc, and sall-4 in SGC-7901 cells treated with medium of BM-MSCs which were co-cultured with platelets were detected. SGC-7901 cells were injected into Balb/c nude mice and the extent of lung metastasis was observed. Both in vitro and in vivo assays were used to analyze the effect of platelets on enhancing the ability of BM-MSCs to promote cancer metastasis.

Results

Results suggested that BM-MSCs and tumor cells can promote platelet aggregation rate and the expression of P-selectin. The protein levels of α-smooth muscle actin, vimentin, and fibroblast activation protein in BM-MSCs were higher after co-incubation with platelets, and SB431542 was used to confirm the effect of TGF-β on transdifferentiation of BM-MSCs into cancer-associated fibroblasts. Medium of BM-MSCs treated with platelets enhanced the proliferation and migration ability of SGC-7901 cells. More lung metastases were found in mice which were injected with SGC-7901 cells treated with conditioned medium from BM-MSCs co-incubated with platelets.

Conclusion

Tumor cells and BM-MSCs activate platelets which can change the characteristics of BM-MSCs through secretion of TGF-β. Moreover, we found that platelets enhanced the effect of BM-MSCs on tumor metastasis, which suggested a potential target and approach for gastric cancer therapy.

Nomogram predicting extrahepatic metastasis of hepatocellular carcinoma based on commonly available clinical data

Background and Aim

Extrahepatic metastasis (EHM) of hepatocellular carcinoma (HCC) leads to a worse prognosis. We aimed to develop a nomogram based on noninvasive pretreatment clinical data to predict EHM of HCC sooner.

Methods

Three cohorts containing 1820, 479, and 988 HCC patients were enrolled from three hospitals in different regions in Taiwan and served as the training and validation cohorts. Pretreatment clinical data were analyzed by Cox regression modeling for independent risk factors of EHM.

Results

Platelet count ≥ 200 × 10³/μL, serum alfa-fetoprotein ≥ 100 ng/dL, tumor size ≥ 3 cm, tumor number > 1, and macrovascular invasion were independent risk factors for EHM and were used to develop a nomogram. This nomogram had concordance indices of 0.733 (95% confidence interval [CI]: 0.688-0.778) and 0.739 (95% CI: 0.692-0.787) for the prediction of EHM during a 5-year follow-up duration in the training and validation cohorts, respectively. A nomogram score > 61 implied a high risk of EHM (hazard ratio [HR] = 3.83; 95% CI: 2.77-5.31, P < 0.001).

Conclusion

We have developed a nomogram that could accurately predict EHM of HCC and be readily available for formulating individualized treatment for all individual HCC patients to improve therapeutic efficacy.

The prognostic value of preoperative inflammatory indexes in gallbladder carcinoma with hepatic involvement

BACKGROUND

Neutrophil-Lymphocyte Ratio (NLR) and Platelet-Lymphocyte Ratio (PLR) have been considered as indicators for prognosis in various cancers. However, the prognostic values of NLR and PLR have never been tested in gallbladder carcinoma (GBC) with hepatic involvement.

OBJECTIVE

The aim of the current study was to assess the prognostic significance of NLR, PLR, and other candidate biomarkers in GBC with liver involvement.

METHODS

Receiver operating characteristic (ROC) curve analyses were utilized to pinpoint the cut-off values for NLR, PLR, and Monocyte-Lymphocyte Ratio (MLR). Univariate analyses were employed to estimate the impact of NLR, PLR, MLR, and other inflammatory indexes on median survival. Multivariate analyses were used to verify the independent prognostic predictors.

RESULTS

Eighty four patients were enrolled from 2009 to 2017. The cut-off values for NLR, PLR, and MLR were 3.20, 117.75, and 0.25, respectively. Univariate analyses revealed that TNM stage, NLR, PLR, MLR, lactate dehydrogenase, alkaline phosphatase, and carcinoembryonic antigen were significantly associated with decreased survival in GBC with hepatic involvement. Advanced TNM stage (P< 0.001) and elevated preoperative NLR (P= 0.002) were significantly associated with lower median survival periods, as revealed by multivariate analyses.

CONCLUSIONS

These findings suggest that preoperative NLR may be an independent prognostic factor in evaluating prognosis in GBC with liver involvement.

The prognostic impact of neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio in patients with advanced colorectal cancer treated with first-line chemotherapy

Introduction

Colorectal cancer is the second most frequently diagnosed malignancy and one of the leading causes of cancer-related death in Poland. Many reports of different types of cancer have indicated that blood count parameters may serve as a source of prognostic or predictive information.

Aim

To assess the association between these parameters and clinical outcome in patients with advanced colorectal cancer.

Material and methods

We retrospectively analysed a database of 295 patients with advanced colorectal cancer treated with first-line palliative chemotherapy at our institution from January 2008 to December 2012. Blood-based parameters were measured before the first cycle of treatment.

Results

The median progression-free survival (PFS) was 6.7 months, and the median overall survival was 17.6 months. A high neutrophil-to-lymphocyte ratio (NLR) and a high platelet-to-lymphocyte ratio (PLR) were associated with a shorter survival (hazard ratio (HR): 1.88, p < 0.0001 for the NLR and HR: 1.39, p = 0.0054 for the PLR), but for the PLR, we observed only a not significant trend toward a worse PFS (HR = 1.25, p = 0.07 for the PLR and HR = 1.55, p = 0.0004 for the NLR). A high lymphocyte-to-monocyte ratio (LMR) was associated with a better prognosis (HR = 0.58, p ≤ 0.0001) and a longer PFS (HR = 0.73, p = 0.011).

Conclusions

The blood-based parameters are readily available, reliable, and low-cost biomarkers, which can be easily incorporated into routine practice to predict the prognosis in patients with advanced colorectal cancer.

Combination of preoperative D-dimer and mean platelet volume predicts postoperative deep venous thrombosis in breast cancer patients

BACKGROUND

Deep venous thrombosis (DVT) is associated with severe morbidity and mortality in cancer. Mean platelet volume (MPV) is an indicator of activated platelets.

OBJECTIVE

We aimed to investigate whether the combination of D-dimer and MPV could have a better performance in predicting deep venous thrombosis (DVT) in patients with breast cancer.

MEHTODS

In 342 consecutive breast cancer patients without preoperative DVT, we measured the preoperative D-dimer and MPV levels. Compression ultrasonography was performed in all breast cancer patients before surgery, as well as one month, three months, six months, and twelve months.

RESULTS

During a median period of twelve months, 15 of the 234 patients (6.4%) developed DVT. MPV was reduced and D-dimer was increased in patients with DVT events compared to those without DVT. Multivariate Cox analysis revealed that both MPV and D-dimer were independent predictors for DVT events. The area under the ROC curve was 0.619 (95% CI: 0.553 to 0.681) when D-dimer was used alone, whereas it increased to 0.790 (95% CI 0.732 to 0.840, p< 0.001) with the addition of MPV.

CONCLUSIONS

The combination of preoperative D-Dimer and MPV improves the predictive power of postoperative DVT risk in breast cancer patients.

Prognostic Role of Platelet-to-Lymphocyte Ratio in Hepatocellular Carcinoma with Different BCLC Stages: A Systematic Review and Meta-Analysis

The role of platelet-to-lymphocyte ratio (PLR) in the prognosis of hepatocellular carcinoma (HCC) patients with different Barcelona Clinic Liver Cancer (BCLC) stages remains controversial. This systematic review and meta-analysis aimed to determine the efficacy of PLR on HCC prognosis. Five electronic databases were searched for clinical trials focusing on the role of PLR in the prognosis of HCC. A total of 297 potential studies were initially identified, and 9 studies comprising 2449 patients were finally enrolled to evaluate the association between the pretreatment PLR and clinical outcomes of overall survival (OS), disease-free survival (DFS), and event occurrence in patients with HCC in different BCLC stages. An elevated pretreatment PLR indicated unfavorable worse OS (HR = 1.73; 95% CI: (1.46, 2.04); P < 0.00001) and DFS (HR = 1.30; 95% CI: (1.06, 1.60); P = 0.01). Subgroup analysis indicated that high PLR indicated poor OS among BCLC-B/C patients without heterogeneity, while PLR in BCLC-A patients indicated high statistical heterogeneity with I² value of 78%. As for the correlation between PLR and event occurrence, high PLR was related to poor clinical event occurrence only among BCLC-C patients, though obvious heterogeneity was observed in all different BCLC stages. In conclusion, PLR may be a significant biomarker in the prognosis of HCC in different BCLC stages.

Nitric oxide deficiency and endothelial-mesenchymal transition of pulmonary endothelium in the progression of 4T1 metastatic breast cancer in mice

Background

Mesenchymal transformation of pulmonary endothelial cells contributes to the formation of a metastatic microenvironment, but it is not known whether this precedes or follows early metastasis formation. In the present work, we characterize the development of nitric oxide (NO) deficiency and markers of endothelial–mesenchymal transition (EndMT) in the lung in relation to the progression of 4T1 metastatic breast cancer injected orthotopically in mice.

Methods

NO production, endothelial nitric oxide synthase (eNOS) phosphorylation status, markers of EndMT in the lung, pulmonary endothelium permeability, and platelet activation/reactivity were analyzed in relation to the progression of 4T1 breast cancer metastasis to the lung, as well as to lung tissue remodeling, 1–5 weeks after 4T1 cancer cell inoculation in Balb/c mice.

Results

Phosphorylation of eNOS and NO production in the lungs of 4T1 breast cancer-bearing mice was compromised prior to the development of pulmonary metastasis, and was associated with overexpression of Snail transcription factor in the pulmonary endothelium. These changes developed prior to the mesenchymal phenotypic switch in the lungs evidenced by a decrease in vascular endothelial-cadherin (VE-CAD) and CD31 expression, and the increase in pulmonary endothelial permeability, phenomena which coincided with early pulmonary metastasis. Increased activation of platelets was also detected prior to the early phase of metastasis and persisted to the late phase of metastasis, as evidenced by the higher percentage of unstimulated platelets binding fibrinogen without changes in von Willebrand factor and fibrinogen binding in response to ADP stimulation.

Conclusions

Decreased eNOS activity and phosphorylation resulting in a low NO production state featuring pulmonary endothelial dysfunction was an early event in breast cancer pulmonary metastasis, preceding the onset of its phenotypic switch toward a mesenchymal phenotype (EndMT) evidenced by a decrease in VE-CAD and CD31 expression. The latter coincided with development of the first metastatic nodules in the lungs. These findings suggest that early endothelial dysfunction featured by NO deficiency rather than EndMT, might represent a primary regulatory target to prevent early pulmonary metastasis.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-1013-z) contains supplementary material, which is available to authorized users.

Drawing a link between the thromboxane A2 pathway and the role of platelets and tumor cells in ovarian cancer

Ovarian cancer is the most lethal gynecologic malignancy among women. Due to the heterogeneity and complexity of the disease, as well as the insidious onset of symptoms, timely diagnosis remains extremely challenging. Despite recent advances in chemotherapy regimens for ovarian cancer patients, many still suffer from recurrence and ultimately succumb to the disease; thus, there is an urgent need for the identification of novel therapeutic targets. Within this rapidly evolving field, the role of platelets in the ovarian cancer tumor microenvironment has garnered increased attention. It is well-established that platelets and tumor cells exhibit bidirectional communication in which platelets enhance tumor cell invasion, extravasation, and protection from host system defenses, while tumor cells serve as platelet agonists, increasing platelet adhesion, aggregation, and degranulation. This mini-review focuses on the platelet-tumor cell relationship in ovarian cancer, specifically highlighting the essential role of bioactive lipid mediators at this interface.

RNA sequencing enables systematic identification of platelet transcriptomic alterations in NSCLC patients

Platelets are implicated as key players in the metastatic dissemination of tumor cells. Previous evidence demonstrated platelets retained cytoplasmic RNAs with physiologically activity, splicing pre-mRNA to mRNA and translating into functional proteins in response to external stimulation. Recently, platelets gene profile of healthy or diseased individuals were characterized with the help of RNA sequencing (RNA-Seq) in some studies, leading to new insights into the mechanisms underlying disease pathogenesis. In this study, we performed RNA-seq in platelets from 7 healthy individuals and 15 non-small cell lung cancer (NSCLC) patients. Our data revealed a subset of near universal differently expressed gene (DEG) profiles in platelets of metastatic NSCLC compared to healthy individuals, including 626 up-regulated RNAs (mRNAs and ncRNAs) and 1497 down-regulated genes. The significant over-expressed genes showed enrichment in focal adhesion, platelets activation, gap junction and adherens junction pathways. The DEGs also included previously reported tumor-related genes such as PDGFR, VEGF, EGF, etc., verifying the consistence and significance of platelet RNA-Seq in oncology study. We also validated several up-regulated DEGs involved in tumor cell-induced platelet aggregation (TCIPA) and tumorigenesis. Additionally, transcriptomic comparison analyses of NSCLC subgroups were conducted. Between non-metastatic and metastatic NSCLC patients, 526 platelet DEGs were identified with the most altered expression. The outcomes from subgroup analysis between lung adenocarcinoma and lung squamous cell carcinoma demonstrated the diagnostic potential of platelet RNA-Seq on distinguishing tumor histological types.

Pretreatment neutrophil-lymphocyte and platelet-lymphocyte ratio predict clinical outcome and prognosis for cervical Cancer

Variations in systemic inflammatory response biomarker levels have been associated with adverse clinical outcome in various malignancies. In this study, we aimed to evaluate the predictive and prognostic role of the pretreatment neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in cervical cancer. We retrospectively investigated 616 patients who underwent initial radical hysterectomy with pelvic lymphadenectomy for cervical cancer between July 2012 and December 2014 in China. Their clinical and histopathological markers and complete blood counts were obtained and analyzed. Then we chose the group of 339 of the total 616 patients who were not combined preoperative radiotherapy or chemotherapy for the survival analysis. Prognostic factors were assessed by univariate and multivariate analyses. The ROC curve revealed NLR and PLR had significant ability to predict parametrial involvement, and the cutoff values for NLR and PLR were 2.5 and 138.8 respectively. Clinicopathologic analysis showed that NLR was linked to age, parametrial involvement, tumor-invasion depth and histologic grade, and PLR was related to age, parametrial involvement, tumor-invasion depth and FIGO stage. Univariate analysis identified high PLR as a significant poor predictor for progression-free survival (PFS) and overall survival (OS), and NLR exhibited no predict power on OS or PFS. Multivariable analysis showed that PLR was an independent predictor of PFS, but not OS. NLR and PLR were associated with the clinical characteristics of cervical cancer. Additionally, PLR had independence prognostic value for PFS in patients with cervical cancer receiving radical hysterectomy with pelvic lymphadenectomy.

PDGF-AB rich-trombocyte lysate supplementation from breast cancer patients increased the proliferation of breast cancer stem cells

Background: Thrombocytosis in breast cancer (BC) patient was thought to play a role in the invasiveness of breast cancer stem cells (BCSCs). Modification of tumor microenvironment was proposed to increase the efficacy of anticancer therapy. This study was aimed to analyze the effect of platelet lysate (PL) as well as its PDGF-AB content as a tumor microenvironment on (CD24-/CD44+) BCSC proliferation.Methods: This was an experimental study that treated culture of BCSCs with PL from breast cancer (BC) patients or healthy donors. Venous blood from all subjects were subjected to prior hematology test and then processed to obtain platelet rich plasma  (PRP). Platelet counts in PRP were determined. PRP was processed to obtain PL. PDGF-AB contents in PL were measured. PL at concentrations of 0.01% (v/v) was supplemented into DMEM-F12 medium and used for culturing BCSCs (CD24-/CD44+ cells). After 48 hours, total cell count, population doubling time (PDT), and cell viability were calculated and their correlation with platelet count and PDGF-AB levels were analyzed.Results: BC patients (n=5) had higher platelet counts and PDGF-AB levels in PL compared to healthy donors (n=15), (p=0.02). PL from BC patients could stimulate the proliferation of BCSCs higher than healthy donors (p<0.001) and showed lower PDT value (p=0.001). Cell proliferation and PDT showed strong correlation with PDGF-AB level. This observation suggests that PDGF-AB has a role on BCSCs proliferation. PL showed no effect on BCSCs viability.Conclusion: Breast cancer patient platelet lysate stimulated BCSC proliferation.

Mean platelet volume predicts survival in pancreatic cancer patients with synchronous liver metastases

Most pancreatic cancer (PC) patients manifest multiple liver metastases at the time of diagnosis. Activated platelets play a key role in tumor growth and tumor metastases. Mean platelet volume (MPV) is a platelet index and is altered in patients with malignancies. This study aimed to evaluate whether MPV can effectively predict death in PC patients with synchronous liver metastases. The clinical data of 411 PC patients with synchronous liver metastases between January 1, 2006 and December 31, 2013 were retrospectively analyzed. Subjects were divided into two groups by MPV levels. Clinicopathological data were collected retrospectively and relationships between MPV levels and clinical parameters were evaluated. Survival analysis was performed. Increased MPV was not significantly correlated with tumor location, tumor size, and CA19.9. The Kaplan-Meier analysis showed that the overall survival of patients with MPV > 8.7 fL was significantly shorter than that of those with MPV ≤ 8.7 fL (log-rank p < 0.001). Multivariable Cox proportional hazards model identified MPV as an independent poor prognostic factor for overall survival. In conclusion, elevated MPV is associated with worse survival outcome in PC patients with synchronous liver metastases. Further studies are warranted.

Dual antiplatelet therapy with clopidogrel and aspirin increases mortality in 4T1 metastatic breast cancer-bearing mice by inducing vascular mimicry in primary tumour

Platelet inhibition has been considered an effective strategy for combating cancer metastasis and compromising disease malignancy although recent clinical data provided evidence that long-term platelet inhibition might increase incidence of cancer deaths in initially cancer-free patients. In the present study we demonstrated that dual anti-platelet therapy based on aspirin and clopidogrel (ASA+Cl), a routine regiment in cardiovascular patients, when given to cancer-bearing mice injected orthotopically with 4T1 breast cancer cells, promoted progression of the disease and reduced mice survival in association with induction of vascular mimicry (VM) in primary tumour. In contrast, treatment with ASA+Cl or platelet depletion did reduce pulmonary metastasis in mice, if 4T1 cells were injected intravenously. In conclusion, distinct platelet-dependent mechanisms inhibited by ASA+Cl treatment promoted cancer malignancy and VM in the presence of primary tumour and afforded protection against pulmonary metastasis in the absence of primary tumour. In view of our data, long-term inhibition of platelet function by dual anti-platelet therapy (ASA+Cl) might pose a hazard when applied to a patient with undiagnosed and untreated malignant cancer prone to undergo VM.

Platelet-targeted pharmacologic treatments as anti-cancer therapy

Platelets act as multifunctional cells participating in immune response, inflammation, allergy, tissue regeneration, and lymphoangiogenesis. Among the best-established aspects of a role of platelets in non-hemostatic or thrombotic disorders, there is their participation in cancer invasion and metastasis. The interaction of many different cancer cells with platelets leads to platelet activation, and on the other hand platelet activation is strongly instrumental to the pro-carcinogenic and pro-metastatic activities of platelets. It is thus obvious that over the last years a lot of interest has focused on the possible chemopreventive effect of platelet-targeted pharmacologic treatments. This article gives an overview of the platelet-targeted pharmacologic approaches that have been attempted in the prevention of cancer development, progression, and metastasis, including the application of anti-platelet drugs currently used for cardiovascular disease and of new and novel pharmacologic strategies. Despite the fact that very promising results have been obtained with some of these approaches in pre-clinical models, with the exclusion of aspirin, clinical evidence of a beneficial effect of anti-platelet agents in cancer is however still largely missing. Future studies with platelet-targeted drugs in cancer must carefully deal with design issues, and in particular with the careful selection of patients, and/or explore novel platelet targets in order to provide a solution to the critical issue of the risk/benefit profile of long-term anti-platelet therapy in the prevention of cancer progression and dissemination.

Norcantharidin, a clinical used chemotherapeutic agent, acts as a powerful inhibitor by interfering with fibrinogen-integrin αIIb β3 binding in human platelets

During platelet activation, fibrinogen binds to its specific platelet receptor, integrin α_IIb β₃ , thus completing the final common pathway for platelet aggregation. Norcantharidin (NCTD) is a promising anticancer agent in China from medicinal insect blister beetle. In this study, we provided the evidence to demonstrate NCTD (0.1-1.0 μM) possesses very powerful antiplatelet activity in human platelets; nevertheless, it had no effects on surface P-selectin expression and only slight inhibition on ATP-release reaction in activated platelets. Moreover, NCTD markedly hindered integrin α_IIb β₃ activation by interfering with the binding of FITC-labelled PAC-1. It also markedly reduced the number of adherent platelets and the single platelet spreading area on immobilized fibrinogen as well as clot retraction. Additionally, NCTD attenuated phosphorylation of proteins such as integrin β₃ , Src and FAK in platelets spreading on immobilized fibrinogen. These results indicate that NCTD restricts integrin α_IIb β₃ -mediated outside-in signalling in human platelets. Besides, NCTD substantially prolonged the closure time in human whole blood and increased the occlusion time of thrombotic platelet plug formation and prolonged the bleeding time in mice. In conclusion, NCTD has dual activities, it can be a chemotherapeutic agent for cancer treatment, and the other side it possesses powerful antiplatelet activity for treating thromboembolic disorders.

Risk of posttransplant hepatocellular carcinoma recurrence is greater in recipients with higher platelet counts in living donor liver transplantation

Platelets interact with tumor cells and promote metastasis. The importance of platelets in posttransplant hepatocellular carcinoma (HCC) recurrence is unclear. Thus, we aimed to evaluate the association between preoperative platelet count (PLT) and HCC recurrence after living donor liver transplantation. Of 359 recipients of livers from living donors for HCC, 209 of 240 patients who had preoperative PLT ≤75 × 10⁹ /L were matched with 97 of 119 patients who had preoperative PLT >75 × 10⁹ /L using propensity score matching, with an unfixed matching ratio based on factors such as tumor biology. The cutoff value of 75 × 10⁹ /L was set based on optimum stratification analysis. Survival analysis was performed with death as a competing risk event. The primary outcome was overall HCC recurrence. The median follow-up time was 59 months. Before matching, recurrence probability at 1, 2, and 5 years after transplantation was 4.7%, 9.2%, and 11.3% for the low platelet group and 14.5%, 23.0%, and 30.5% for the high platelet group. Recurrence risk was significantly greater in the high platelet group in both univariate (hazard ratio [HR] = 3.09; 95% confidence interval [CI], 1.86-5.14; P < 0.001) and multivariate analyses (HR = 2.10; 95% CI, 1.23-3.60; P =  0.007). In the matched analysis, recurrence risk was also greater in the high platelet group in both univariate (HR = 2.33; 95% CI, 1.36-4.01; P =  0.002) and multivariate analyses (HR = 1.90; 95% CI, 1.02-3.54; P =  0.04). Preoperative PLT had no interaction with the Milan criteria, alpha-fetoprotein level, Edmonson grade, microvascular invasion, or intrahepatic metastasis. Incorporation of preoperative PLT into the Milan criteria significantly improved predictive power. Inflammation-based scores including neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and the inflammation-based index did not show superiority to preoperative PLT in predicting HCC recurrence. In conclusion, preoperative PLT appears to be an important host factor affecting HCC recurrence after living donor liver transplantation. Liver Transplantation 24 44-55 2018 AASLD.

Pretreatment platelet count as a prognostic factor in patients with pancreatic cancer: a systematic review and meta-analysis

Background

The relationship between platelet counts and pancreatic cancer as a prognostic factor has been reported in many studies. We aimed to evaluate the prognostic value of platelet counts in predicting the prognosis of pancreatic cancer patients.

Methods

We searched PubMed, Medline, EMBASE, and Google Scholar for eligible studies up to May 2017. Information about the characteristics of the study and relevant outcomes was extracted. A meta-analysis was performed to analyze the prognostic value of platelet counts using the hazard ratio (HR) and 95% confidence intervals (CIs).

Results

A total of 1,756 patients in 13 retrospective studies were included. The pooled HR of 1.51 (95% CI: 1.20–1.90, P<0.001) showed that patients with elevated platelet counts were expected to have poor overall survival after treatment. Subgroup analysis showed that prognostic value of platelet levels was stronger in patients who received surgical resection (HR =1.60, 95% CI: 1.09–2.34, P=0.02), followed by patients who received palliative therapy (HR =1.46, 95% CI: 1.03–2.06, P=0.03).

Conclusion

Platelet counts could be a useful prognostic marker for pancreatic cancer. Patients with high platelet counts are expected to have poor survival.

Clinicopathological and prognostic significance of platelet count in patients with ovarian cancer

AIM

Increasing evidence indicates that platelet count is a useful biomarker of long-term outcomes in patients with ovarian cancer. However, the prognostic value of platelet count in patients with ovarian cancer remains controversial. We therefore conducted a meta-analysis aimed to investigate the prognostic role of the platelet count in patients with ovarian cancer.

METHOD

A comprehensive search was performed from the databases of PubMed, Embase and the Cochrane Library until June 20, 2017. A total of 18 studies with 6754 patients were included. Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) and odds ratios and 95% CIs from each study were pooled.

RESULTS

The results demonstrated that elevated pretreatment platelet count was significantly related to poor survival from ovarian cancer; the pooled HRs for overall, progression-free and disease-free survival were 1.81 (95% CI 1.52-2.15), 1.48 (95% CI 1.24-1.75) and 1.39 (95% CI 1.19-1.61), respectively. Subgroup analyses were divided by ethnicity, sample size, FIGO stage, cut-off value of the platelet count, analysis method and Newcastle Ottawa Scale score, but the results did not show any significant change in the main results. Increased platelet count was also significantly associated with the FIGO stage, tumor differentiation, ascites, residual tumor mass, CA125 level, recurrence and metastasis.

CONCLUSION

This meta-analysis revealed that an elevated platelet count pretreatment denotes a predictive factor of poor prognosis and unfavorable clinicopathological parameters for ovarian cancer patients.

New Therapeutic Agent against Arterial Thrombosis: An Iridium(III)-Derived Organometallic Compound

Platelet activation plays a major role in cardio and cerebrovascular diseases, and cancer progression. Disruption of platelet activation represents an attractive therapeutic target for reducing the bidirectional cross talk between platelets and tumor cells. Platinum (Pt) compounds have been used for treating cancer. Hence, replacing Pt with iridium (Ir) is considered a potential alternative. We recently developed an Ir(III)-derived complex, [Ir(Cp*)1-(2-pyridyl)-3-(2-hydroxyphenyl)imidazo[1,5-a]pyridine Cl]BF₄ (Ir-11), which exhibited strong antiplatelet activity; hence, we assessed the therapeutic potential of Ir-11 against arterial thrombosis. In collagen-activated platelets, Ir-11 inhibited platelet aggregation, adenosine triphosphate (ATP) release, intracellular Ca²⁺ mobilization, P-selectin expression, and OH· formation, as well as the phosphorylation of phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and Akt. Neither the adenylate cyclase inhibitor nor the guanylate cyclase inhibitor reversed the Ir-11-mediated antiplatelet effects. In experimental mice, Ir-11 prolonged the bleeding time and reduced mortality associated with acute pulmonary thromboembolism. Ir-11 plays a crucial role by inhibiting platelet activation through the inhibition of the PLCγ2–PKC cascade, and the subsequent suppression of Akt and MAPK activation, ultimately inhibiting platelet aggregation. Therefore, Ir-11 can be considered a new therapeutic agent against either arterial thrombosis or the bidirectional cross talk between platelets and tumor cells.

Lung as a Niche for Hematopoietic Progenitors

Platelets are released from megakaryocytes. The bone marrow has been proposed to be the major site where this process occurs. Lefrançais et al. (2017) using state-of-the-art techniques including two-photon microscopy, in vivo lineage-tracing technologies, and sophisticated lung transplants reveal that the lung is also a primary site for platelet biogenesis. Strikingly, lung megakaryocytes can completely reconstitute platelet counts in the blood in mice with thrombocytopenia. This study also shows that hematopoietic progenitors, with capacity to repopulate the bone marrow after irradiation, are present in the lungs. This work brings a novel unexpected role for the lung as a niche for hematopoiesis. The emerging knowledge from this research may be important for the treatment of several disorders.

Platelet Integrins in Tumor Metastasis: Do They Represent a Therapeutic Target?

Platelets are small anucleated cell fragments that ensure the arrest of bleeding after a vessel wall injury. They are also involved in non-hemostatic function such as development, immunity, inflammation, and in the hematogeneous phase of metastasis. While the role of platelets in tumor metastasis has been recognized for 60 years, the molecular mechanism underlying this process remains largely unclear. Platelets physically and functionally interact with various tumor cells through surface receptors including integrins. Platelets express five integrins at their surface, namely α2β1, α5β1, α6β1, αvβ3, and αIIbβ3, which bind preferentially to collagen, fibronectin, laminin, vitronectin, and fibrinogen, respectively. The main role of platelet integrins is to ensure platelet adhesion and aggregation at sites of vascular injury. Two of these, α6β1 and αIIbβ3, were proposed to participate in platelet–tumor cell interaction and in tumor metastasis. It has also been reported that pharmacological agents targeting both integrins efficiently reduce experimental metastasis, suggesting that platelet integrins may represent new anti-metastatic targets. This review focuses on the role of platelet integrins in tumor metastasis and discusses whether these receptors may represent new potential targets for novel anti-metastatic approaches.

Prognostic role of the pre-treatment platelet-lymphocyte ratio in pancreatic cancer: a meta-analysis

Background and Aims

Recently, the pre-treatment platelet-lymphocyte ratio (PLR), which is based on blood parameters, was accepted as a prognostic factor for patients with various cancers. Numerous studies have investigated the prognostic role of the PLR in pancreatic cancer; however, it remains unclear. Therefore, we conducted this meta-analysis to evaluate the relationship between the pre-treatment PLR and overall survival (OS) in pancreatic cancer.

Materials and Methods

We performed a systematic literature search of the PubMed, Embase and Web of Science databases for relevant studies that explored the prognostic role of the pre-treatment PLR in pancreatic cancer. The hazard ratios (HRs) and 95% confidence intervals (CIs) related to OS were pooled using a random effects model.

Results

Fourteen retrospective cohort studies involving 2,260 patients were included in this meta-analysis. Compared with low PLR, high PLR was a predictor of shorter OS (HR = 1.24, 95% CI: 1.10–1.39, I² = 74%).

Conclusions

In this meta-analysis, high pre-treatment PLR was a bio-predictor of short OS in patients with pancreatic cancer, suggesting that PLR could be used to predict prognosis of patients with pancreatic cancer before treatment. However, additional well-designed and large-scale studies are necessary.

The Potential Role of Senescence As a Modulator of Platelets and Tumorigenesis

In addition to thrombus formation, alterations in platelet function are frequently observed in cancer patients. Importantly, both thrombus and tumor formation are influenced by age, although the mechanisms through which physiological aging modulates these processes remain poorly understood. In this context, the potential effects of senescent cells on platelet function represent pathophysiological mechanisms that deserve further exploration. Cellular senescence has traditionally been viewed as a barrier to tumorigenesis. However, far from being passive bystanders, senescent cells are metabolically active and able to secrete a variety of soluble and insoluble factors. This feature, known as the senescence-associated secretory phenotype (SASP), may provide senescent cells with the capacity to modify the tissue environment and, paradoxically, promote proliferation and neoplastic transformation of neighboring cells. In fact, the SASP-dependent ability of senescent cells to enhance tumorigenesis has been confirmed in cellular systems involving epithelial cells and fibroblasts, leaving open the question as to whether similar interactions can be extended to other cellular contexts. In this review, we discuss the diverse functions of platelets in tumorigenesis and suggest the possibility that senescent cells might also influence tumorigenesis through their ability to modulate the functional status of platelets through the SASP.

Prognostic value of combination of preoperative platelet count and mean platelet volume in patients with resectable non-small cell lung cancer

The aim of the present study was to investigate the prognostic value of the combination of preoperative platelet count (PLT) and mean platelet volume (MPV) in patients with primary operable non-small cell lung cancer (NSCLC). We retrospectively analysed data from 546 patients with NSCLC who underwent complete resection at our institution from 2006 to 2010. Patients’ clinical characteristics and laboratory test data at initial diagnosis were collected. Both preoperative PLT and MPV (COP-MPV) were calculated on the basis of the data obtained using the recommended cut-off values of 300 × 10⁹ L⁻¹ and 11.0 fL, respectively. Patients with both an elevated PLT (≥300× 10⁹ L⁻¹) and a decreased MPV (<11.0 fL) were assigned a score of 2, and patients showing one or neither were allocated a score of 1 or 0, respectively. Multivariate analysis of the 9 clinical laboratory variables selected by univariate analysis revealed that preoperative COP-MPV was a significantly independent prognostic factor for overall survival (OS) (hazard ratio, 1.775; 95% confidence interval, 1.500–2.101; P< 0.001) and disease-free survival (DFS) (hazard ratio, 1.719; 95% confidence interval, 1.454–2.033; P< 0.001). In subgroup analyses for tumour pathological stage (I/II/IIIA) patients, we found that the level of COP-MPV was significantly associated with OS and DFS in each subgroup (P< 0.001, P< 0.001, P<0.001 for OS and P<0.001, P< 0.001, P=0.001 for DFS, respectively). In conclusion, the preoperative COP-MPV is a promising predictor of postoperative survival in patients with NSCLC and could classify these patients into three independent groups before surgery.

Coagulation and fibrinolysis in gastric cancer

Coagulation is a highly conserved process occurring after an injury to a blood vessel and resulting in hemostasis. In the thrombus microenvironment, finely orchestrated events restore vessel integrity through platelet activation, adhesion, and aggregation (primary hemostasis), followed by the coagulation cascades, thrombin generation, and fibrin clot deposition (secondary hemostasis). Several studies on cancer have provided insight into dramatic changes to coagulation-related events (i.e., fibrin clot deposition, fibrinolysis) during tumor pathogenesis, progression, and metastasis, in addition to a tumor-driven systemic activation of hemostasis and thrombosis (Trousseau's syndrome). Diverse molecular and cellular effectors participate in the cross talk between hemostasis and tumors. Here, we focus on some aspects of the interconnection between cancer biology and hemostatic components, with particular attention to some key coagulation-related proteins (e.g., tissue factor, thrombin, fibrinogen, and D-dimers) in the particular case of gastric cancer (GC). Recent advances in deciphering the complex molecular link between GC and the coagulation system are described, showing their important roles in better management of patients affected by GC.

Lower mean platelet volume predicts poor prognosis in renal cell carcinoma

Altered mean platelet volume (MPV) is found in several malignancies. Remarkably, there is little consensus on using the value of MPV in the prognostic evaluations of renal cell carcinoma (RCC). The aim of this study is to examine the feasibility of MPV value as a prognostic indicator of RCC. The retrospective study recruited 306 consecutive RCC patients between January 2009 and December 2009. The relationships between MPV and clinicopathological characteristics were analyzed. Kaplan-Meier method and Cox regression were used to evaluate the prognostic impact of MPV. Of the 306 RCC patients, low MPV levels were detected in 61 (19.9%) patients. Reduced MPV was associated with histology types, T classification, UCLA Integrated Scoring System (UISS) category, and Mayo clinic stage, size, grade, and necrosis score (SSIGN) category (P < 0.05). Patients with decreased MPV had significantly shorter survival time than patients with normal MPV (P < 0.001). Cox regression analysis revealed that reduced MPV was an independent prognostic factor for overall survival (hazard ratio, 1.758; 95% confidence interval [CI], 1.083–2.855, P = 0.023). Moreover, the prognostic accuracy of TNM stage, UISS, and SSIGN prognostic models were improved when MPV was added. In conclusion, reduced MPV is identified as an independent predictor of adverse clinical outcome in RCC.